Merge tag 'drm-next-2019-07-16' of git://anongit.freedesktop.org/drm/drm

Pull drm updates from Dave Airlie:
 "The biggest thing in this is the AMD Navi GPU support, this again
  contains a bunch of header files that are large. These are the new AMD
  RX5700 GPUs that just recently became available.

  New drivers:
   - ST-Ericsson MCDE driver
   - Ingenic JZ47xx SoC

  UAPI change:
   - HDR source metadata property

  Core:
   - HDR inforframes and EDID parsing
   - drm hdmi infoframe unpacking
   - remove prime sg_table caching into dma-buf
   - New gem vram helpers to reduce driver code
   - Lots of drmP.h removal
   - reservation fencing fix
   - documentation updates
   - drm_fb_helper_connector removed
   - mode name command handler rewrite

  fbcon:
   - Remove the fbcon notifiers

  ttm:
   - forward progress fixes

  dma-buf:
   - make mmap call optional
   - debugfs refcount fixes
   - dma-fence free with pending signals fix
   - each dma-buf gets an inode

  Panels:
   - Lots of additional panel bindings

  amdgpu:
   - initial navi10 support
   - avoid hw reset
   - HDR metadata support
   - new thermal sensors for vega asics
   - RAS fixes
   - use HMM rather than MMU notifier
   - xgmi topology via kfd
   - SR-IOV fixes
   - driver reload fixes
   - DC use a core bpc attribute
   - Aux fixes for DC
   - Bandwidth calc updates for DC
   - Clock handling refactor
   - kfd VEGAM support

  vmwgfx:
   - Coherent memory support changes

  i915:
   - HDR Support
   - HDMI i2c link
   - Icelake multi-segmented gamma support
   - GuC firmware update
   - Mule Creek Canyon PCH support for EHL
   - EHL platform updtes
   - move i915.alpha_support to i915.force_probe
   - runtime PM refactoring
   - VBT parsing refactoring
   - DSI fixes
   - struct mutex dependency reduction
   - GEM code reorg

  mali-dp:
   - Komeda driver features

  msm:
   - dsi vs EPROBE_DEFER fixes
   - msm8998 snapdragon 835 support
   - a540 gpu support
   - mdp5 and dpu interconnect support

  exynos:
   - drmP.h removal

  tegra:
   - misc fixes

  tda998x:
   - audio support improvements
   - pixel repeated mode support
   - quantisation range handling corrections
   - HDMI vendor info fix

  armada:
   - interlace support fix
   - overlay/video plane register handling refactor
   - add gamma support

  rockchip:
   - RX3328 support

  panfrost:
   - expose perf counters via hidden ioctls

  vkms:
   - enumerate CRC sources list

  ast:
   - rework BO handling

  mgag200:
   - rework BO handling

  dw-hdmi:
   - suspend/resume support

  rcar-du:
   - R8A774A1 Soc Support
   - LVDS dual-link mode support
   - Additional formats
   - Misc fixes

  omapdrm:
   - DSI command mode display support

  stm
   - fb modifier support
   - runtime PM support

  sun4i:
   - use vmap ops

  vc4:
   - binner bo binding rework

  v3d:
   - compute shader support
   - resync/sync fixes
   - job management refactoring

  lima:
   - NULL pointer in irq handler fix
   - scheduler default timeout

  virtio:
   - fence seqno support
   - trace events

  bochs:
   - misc fixes

  tc458767:
   - IRQ/HDP handling

  sii902x:
   - HDMI audio support

  atmel-hlcdc:
   - misc fixes

  meson:
   - zpos support"

* tag 'drm-next-2019-07-16' of git://anongit.freedesktop.org/drm/drm: (1815 commits)
  Revert "Merge branch 'vmwgfx-next' of git://people.freedesktop.org/~thomash/linux into drm-next"
  Revert "mm: adjust apply_to_pfn_range interface for dropped token."
  mm: adjust apply_to_pfn_range interface for dropped token.
  drm/amdgpu/navi10: add uclk activity sensor
  drm/amdgpu: properly guard the generic discovery code
  drm/amdgpu: add missing documentation on new module parameters
  drm/amdgpu: don't invalidate caches in RELEASE_MEM, only do the writeback
  drm/amd/display: avoid 64-bit division
  drm/amdgpu/psp11: simplify the ucode register logic
  drm/amdgpu: properly guard DC support in navi code
  drm/amd/powerplay: vega20: fix uninitialized variable use
  drm/amd/display: dcn20: include linux/delay.h
  amdgpu: make pmu support optional
  drm/amd/powerplay: Zero initialize current_rpm in vega20_get_fan_speed_percent
  drm/amd/powerplay: Zero initialize freq in smu_v11_0_get_current_clk_freq
  drm/amd/powerplay: Use memset to initialize metrics structs
  drm/amdgpu/mes10.1: Fix header guard
  drm/amd/powerplay: add temperature sensor support for navi10
  drm/amdgpu: fix scheduler timeout calc
  drm/amdgpu: Prepare for hmm_range_register API change (v2)
  ...

1 files changed, 2051 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
new file mode 100644
index 000000000000..39d742094065
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_panel.c
@@ -0,0 +1,2051 @@
+/*
+ * Copyright © 2006-2010 Intel Corporation
+ * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *	Eric Anholt <eric@anholt.net>
+ *      Dave Airlie <airlied@linux.ie>
+ *      Jesse Barnes <jesse.barnes@intel.com>
+ *      Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include <linux/pwm.h>
+
+#include "intel_connector.h"
+#include "intel_dp_aux_backlight.h"
+#include "intel_drv.h"
+#include "intel_dsi_dcs_backlight.h"
+#include "intel_panel.h"
+
+#define CRC_PMIC_PWM_PERIOD_NS	21333
+
+void
+intel_fixed_panel_mode(const struct drm_display_mode *fixed_mode,
+		       struct drm_display_mode *adjusted_mode)
+{
+	drm_mode_copy(adjusted_mode, fixed_mode);
+
+	drm_mode_set_crtcinfo(adjusted_mode, 0);
+}
+
+static bool is_downclock_mode(const struct drm_display_mode *downclock_mode,
+			      const struct drm_display_mode *fixed_mode)
+{
+	return drm_mode_match(downclock_mode, fixed_mode,
+			      DRM_MODE_MATCH_TIMINGS |
+			      DRM_MODE_MATCH_FLAGS |
+			      DRM_MODE_MATCH_3D_FLAGS) &&
+		downclock_mode->clock < fixed_mode->clock;
+}
+
+struct drm_display_mode *
+intel_panel_edid_downclock_mode(struct intel_connector *connector,
+				const struct drm_display_mode *fixed_mode)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	const struct drm_display_mode *scan, *best_mode = NULL;
+	struct drm_display_mode *downclock_mode;
+	int best_clock = fixed_mode->clock;
+
+	list_for_each_entry(scan, &connector->base.probed_modes, head) {
+		/*
+		 * If one mode has the same resolution with the fixed_panel
+		 * mode while they have the different refresh rate, it means
+		 * that the reduced downclock is found. In such
+		 * case we can set the different FPx0/1 to dynamically select
+		 * between low and high frequency.
+		 */
+		if (is_downclock_mode(scan, fixed_mode) &&
+		    scan->clock < best_clock) {
+			/*
+			 * The downclock is already found. But we
+			 * expect to find the lower downclock.
+			 */
+			best_clock = scan->clock;
+			best_mode = scan;
+		}
+	}
+
+	if (!best_mode)
+		return NULL;
+
+	downclock_mode = drm_mode_duplicate(&dev_priv->drm, best_mode);
+	if (!downclock_mode)
+		return NULL;
+
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] using downclock mode from EDID: ",
+		      connector->base.base.id, connector->base.name);
+	drm_mode_debug_printmodeline(downclock_mode);
+
+	return downclock_mode;
+}
+
+struct drm_display_mode *
+intel_panel_edid_fixed_mode(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	const struct drm_display_mode *scan;
+	struct drm_display_mode *fixed_mode;
+
+	if (list_empty(&connector->base.probed_modes))
+		return NULL;
+
+	/* prefer fixed mode from EDID if available */
+	list_for_each_entry(scan, &connector->base.probed_modes, head) {
+		if ((scan->type & DRM_MODE_TYPE_PREFERRED) == 0)
+			continue;
+
+		fixed_mode = drm_mode_duplicate(&dev_priv->drm, scan);
+		if (!fixed_mode)
+			return NULL;
+
+		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] using preferred mode from EDID: ",
+			      connector->base.base.id, connector->base.name);
+		drm_mode_debug_printmodeline(fixed_mode);
+
+		return fixed_mode;
+	}
+
+	scan = list_first_entry(&connector->base.probed_modes,
+				typeof(*scan), head);
+
+	fixed_mode = drm_mode_duplicate(&dev_priv->drm, scan);
+	if (!fixed_mode)
+		return NULL;
+
+	fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
+
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] using first mode from EDID: ",
+		      connector->base.base.id, connector->base.name);
+	drm_mode_debug_printmodeline(fixed_mode);
+
+	return fixed_mode;
+}
+
+struct drm_display_mode *
+intel_panel_vbt_fixed_mode(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct drm_display_info *info = &connector->base.display_info;
+	struct drm_display_mode *fixed_mode;
+
+	if (!dev_priv->vbt.lfp_lvds_vbt_mode)
+		return NULL;
+
+	fixed_mode = drm_mode_duplicate(&dev_priv->drm,
+					dev_priv->vbt.lfp_lvds_vbt_mode);
+	if (!fixed_mode)
+		return NULL;
+
+	fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
+
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] using mode from VBT: ",
+		      connector->base.base.id, connector->base.name);
+	drm_mode_debug_printmodeline(fixed_mode);
+
+	info->width_mm = fixed_mode->width_mm;
+	info->height_mm = fixed_mode->height_mm;
+
+	return fixed_mode;
+}
+
+/* adjusted_mode has been preset to be the panel's fixed mode */
+void
+intel_pch_panel_fitting(struct intel_crtc *intel_crtc,
+			struct intel_crtc_state *pipe_config,
+			int fitting_mode)
+{
+	const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
+	int x = 0, y = 0, width = 0, height = 0;
+
+	/* Native modes don't need fitting */
+	if (adjusted_mode->crtc_hdisplay == pipe_config->pipe_src_w &&
+	    adjusted_mode->crtc_vdisplay == pipe_config->pipe_src_h &&
+	    pipe_config->output_format != INTEL_OUTPUT_FORMAT_YCBCR420)
+		goto done;
+
+	switch (fitting_mode) {
+	case DRM_MODE_SCALE_CENTER:
+		width = pipe_config->pipe_src_w;
+		height = pipe_config->pipe_src_h;
+		x = (adjusted_mode->crtc_hdisplay - width + 1)/2;
+		y = (adjusted_mode->crtc_vdisplay - height + 1)/2;
+		break;
+
+	case DRM_MODE_SCALE_ASPECT:
+		/* Scale but preserve the aspect ratio */
+		{
+			u32 scaled_width = adjusted_mode->crtc_hdisplay
+				* pipe_config->pipe_src_h;
+			u32 scaled_height = pipe_config->pipe_src_w
+				* adjusted_mode->crtc_vdisplay;
+			if (scaled_width > scaled_height) { /* pillar */
+				width = scaled_height / pipe_config->pipe_src_h;
+				if (width & 1)
+					width++;
+				x = (adjusted_mode->crtc_hdisplay - width + 1) / 2;
+				y = 0;
+				height = adjusted_mode->crtc_vdisplay;
+			} else if (scaled_width < scaled_height) { /* letter */
+				height = scaled_width / pipe_config->pipe_src_w;
+				if (height & 1)
+				    height++;
+				y = (adjusted_mode->crtc_vdisplay - height + 1) / 2;
+				x = 0;
+				width = adjusted_mode->crtc_hdisplay;
+			} else {
+				x = y = 0;
+				width = adjusted_mode->crtc_hdisplay;
+				height = adjusted_mode->crtc_vdisplay;
+			}
+		}
+		break;
+
+	case DRM_MODE_SCALE_FULLSCREEN:
+		x = y = 0;
+		width = adjusted_mode->crtc_hdisplay;
+		height = adjusted_mode->crtc_vdisplay;
+		break;
+
+	default:
+		WARN(1, "bad panel fit mode: %d\n", fitting_mode);
+		return;
+	}
+
+done:
+	pipe_config->pch_pfit.pos = (x << 16) | y;
+	pipe_config->pch_pfit.size = (width << 16) | height;
+	pipe_config->pch_pfit.enabled = pipe_config->pch_pfit.size != 0;
+}
+
+static void
+centre_horizontally(struct drm_display_mode *adjusted_mode,
+		    int width)
+{
+	u32 border, sync_pos, blank_width, sync_width;
+
+	/* keep the hsync and hblank widths constant */
+	sync_width = adjusted_mode->crtc_hsync_end - adjusted_mode->crtc_hsync_start;
+	blank_width = adjusted_mode->crtc_hblank_end - adjusted_mode->crtc_hblank_start;
+	sync_pos = (blank_width - sync_width + 1) / 2;
+
+	border = (adjusted_mode->crtc_hdisplay - width + 1) / 2;
+	border += border & 1; /* make the border even */
+
+	adjusted_mode->crtc_hdisplay = width;
+	adjusted_mode->crtc_hblank_start = width + border;
+	adjusted_mode->crtc_hblank_end = adjusted_mode->crtc_hblank_start + blank_width;
+
+	adjusted_mode->crtc_hsync_start = adjusted_mode->crtc_hblank_start + sync_pos;
+	adjusted_mode->crtc_hsync_end = adjusted_mode->crtc_hsync_start + sync_width;
+}
+
+static void
+centre_vertically(struct drm_display_mode *adjusted_mode,
+		  int height)
+{
+	u32 border, sync_pos, blank_width, sync_width;
+
+	/* keep the vsync and vblank widths constant */
+	sync_width = adjusted_mode->crtc_vsync_end - adjusted_mode->crtc_vsync_start;
+	blank_width = adjusted_mode->crtc_vblank_end - adjusted_mode->crtc_vblank_start;
+	sync_pos = (blank_width - sync_width + 1) / 2;
+
+	border = (adjusted_mode->crtc_vdisplay - height + 1) / 2;
+
+	adjusted_mode->crtc_vdisplay = height;
+	adjusted_mode->crtc_vblank_start = height + border;
+	adjusted_mode->crtc_vblank_end = adjusted_mode->crtc_vblank_start + blank_width;
+
+	adjusted_mode->crtc_vsync_start = adjusted_mode->crtc_vblank_start + sync_pos;
+	adjusted_mode->crtc_vsync_end = adjusted_mode->crtc_vsync_start + sync_width;
+}
+
+static inline u32 panel_fitter_scaling(u32 source, u32 target)
+{
+	/*
+	 * Floating point operation is not supported. So the FACTOR
+	 * is defined, which can avoid the floating point computation
+	 * when calculating the panel ratio.
+	 */
+#define ACCURACY 12
+#define FACTOR (1 << ACCURACY)
+	u32 ratio = source * FACTOR / target;
+	return (FACTOR * ratio + FACTOR/2) / FACTOR;
+}
+
+static void i965_scale_aspect(struct intel_crtc_state *pipe_config,
+			      u32 *pfit_control)
+{
+	const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
+	u32 scaled_width = adjusted_mode->crtc_hdisplay *
+		pipe_config->pipe_src_h;
+	u32 scaled_height = pipe_config->pipe_src_w *
+		adjusted_mode->crtc_vdisplay;
+
+	/* 965+ is easy, it does everything in hw */
+	if (scaled_width > scaled_height)
+		*pfit_control |= PFIT_ENABLE |
+			PFIT_SCALING_PILLAR;
+	else if (scaled_width < scaled_height)
+		*pfit_control |= PFIT_ENABLE |
+			PFIT_SCALING_LETTER;
+	else if (adjusted_mode->crtc_hdisplay != pipe_config->pipe_src_w)
+		*pfit_control |= PFIT_ENABLE | PFIT_SCALING_AUTO;
+}
+
+static void i9xx_scale_aspect(struct intel_crtc_state *pipe_config,
+			      u32 *pfit_control, u32 *pfit_pgm_ratios,
+			      u32 *border)
+{
+	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
+	u32 scaled_width = adjusted_mode->crtc_hdisplay *
+		pipe_config->pipe_src_h;
+	u32 scaled_height = pipe_config->pipe_src_w *
+		adjusted_mode->crtc_vdisplay;
+	u32 bits;
+
+	/*
+	 * For earlier chips we have to calculate the scaling
+	 * ratio by hand and program it into the
+	 * PFIT_PGM_RATIO register
+	 */
+	if (scaled_width > scaled_height) { /* pillar */
+		centre_horizontally(adjusted_mode,
+				    scaled_height /
+				    pipe_config->pipe_src_h);
+
+		*border = LVDS_BORDER_ENABLE;
+		if (pipe_config->pipe_src_h != adjusted_mode->crtc_vdisplay) {
+			bits = panel_fitter_scaling(pipe_config->pipe_src_h,
+						    adjusted_mode->crtc_vdisplay);
+
+			*pfit_pgm_ratios |= (bits << PFIT_HORIZ_SCALE_SHIFT |
+					     bits << PFIT_VERT_SCALE_SHIFT);
+			*pfit_control |= (PFIT_ENABLE |
+					  VERT_INTERP_BILINEAR |
+					  HORIZ_INTERP_BILINEAR);
+		}
+	} else if (scaled_width < scaled_height) { /* letter */
+		centre_vertically(adjusted_mode,
+				  scaled_width /
+				  pipe_config->pipe_src_w);
+
+		*border = LVDS_BORDER_ENABLE;
+		if (pipe_config->pipe_src_w != adjusted_mode->crtc_hdisplay) {
+			bits = panel_fitter_scaling(pipe_config->pipe_src_w,
+						    adjusted_mode->crtc_hdisplay);
+
+			*pfit_pgm_ratios |= (bits << PFIT_HORIZ_SCALE_SHIFT |
+					     bits << PFIT_VERT_SCALE_SHIFT);
+			*pfit_control |= (PFIT_ENABLE |
+					  VERT_INTERP_BILINEAR |
+					  HORIZ_INTERP_BILINEAR);
+		}
+	} else {
+		/* Aspects match, Let hw scale both directions */
+		*pfit_control |= (PFIT_ENABLE |
+				  VERT_AUTO_SCALE | HORIZ_AUTO_SCALE |
+				  VERT_INTERP_BILINEAR |
+				  HORIZ_INTERP_BILINEAR);
+	}
+}
+
+void intel_gmch_panel_fitting(struct intel_crtc *intel_crtc,
+			      struct intel_crtc_state *pipe_config,
+			      int fitting_mode)
+{
+	struct drm_i915_private *dev_priv = to_i915(intel_crtc->base.dev);
+	u32 pfit_control = 0, pfit_pgm_ratios = 0, border = 0;
+	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
+
+	/* Native modes don't need fitting */
+	if (adjusted_mode->crtc_hdisplay == pipe_config->pipe_src_w &&
+	    adjusted_mode->crtc_vdisplay == pipe_config->pipe_src_h)
+		goto out;
+
+	switch (fitting_mode) {
+	case DRM_MODE_SCALE_CENTER:
+		/*
+		 * For centered modes, we have to calculate border widths &
+		 * heights and modify the values programmed into the CRTC.
+		 */
+		centre_horizontally(adjusted_mode, pipe_config->pipe_src_w);
+		centre_vertically(adjusted_mode, pipe_config->pipe_src_h);
+		border = LVDS_BORDER_ENABLE;
+		break;
+	case DRM_MODE_SCALE_ASPECT:
+		/* Scale but preserve the aspect ratio */
+		if (INTEL_GEN(dev_priv) >= 4)
+			i965_scale_aspect(pipe_config, &pfit_control);
+		else
+			i9xx_scale_aspect(pipe_config, &pfit_control,
+					  &pfit_pgm_ratios, &border);
+		break;
+	case DRM_MODE_SCALE_FULLSCREEN:
+		/*
+		 * Full scaling, even if it changes the aspect ratio.
+		 * Fortunately this is all done for us in hw.
+		 */
+		if (pipe_config->pipe_src_h != adjusted_mode->crtc_vdisplay ||
+		    pipe_config->pipe_src_w != adjusted_mode->crtc_hdisplay) {
+			pfit_control |= PFIT_ENABLE;
+			if (INTEL_GEN(dev_priv) >= 4)
+				pfit_control |= PFIT_SCALING_AUTO;
+			else
+				pfit_control |= (VERT_AUTO_SCALE |
+						 VERT_INTERP_BILINEAR |
+						 HORIZ_AUTO_SCALE |
+						 HORIZ_INTERP_BILINEAR);
+		}
+		break;
+	default:
+		WARN(1, "bad panel fit mode: %d\n", fitting_mode);
+		return;
+	}
+
+	/* 965+ wants fuzzy fitting */
+	/* FIXME: handle multiple panels by failing gracefully */
+	if (INTEL_GEN(dev_priv) >= 4)
+		pfit_control |= ((intel_crtc->pipe << PFIT_PIPE_SHIFT) |
+				 PFIT_FILTER_FUZZY);
+
+out:
+	if ((pfit_control & PFIT_ENABLE) == 0) {
+		pfit_control = 0;
+		pfit_pgm_ratios = 0;
+	}
+
+	/* Make sure pre-965 set dither correctly for 18bpp panels. */
+	if (INTEL_GEN(dev_priv) < 4 && pipe_config->pipe_bpp == 18)
+		pfit_control |= PANEL_8TO6_DITHER_ENABLE;
+
+	pipe_config->gmch_pfit.control = pfit_control;
+	pipe_config->gmch_pfit.pgm_ratios = pfit_pgm_ratios;
+	pipe_config->gmch_pfit.lvds_border_bits = border;
+}
+
+/**
+ * scale - scale values from one range to another
+ * @source_val: value in range [@source_min..@source_max]
+ * @source_min: minimum legal value for @source_val
+ * @source_max: maximum legal value for @source_val
+ * @target_min: corresponding target value for @source_min
+ * @target_max: corresponding target value for @source_max
+ *
+ * Return @source_val in range [@source_min..@source_max] scaled to range
+ * [@target_min..@target_max].
+ */
+static u32 scale(u32 source_val,
+		 u32 source_min, u32 source_max,
+		 u32 target_min, u32 target_max)
+{
+	u64 target_val;
+
+	WARN_ON(source_min > source_max);
+	WARN_ON(target_min > target_max);
+
+	/* defensive */
+	source_val = clamp(source_val, source_min, source_max);
+
+	/* avoid overflows */
+	target_val = mul_u32_u32(source_val - source_min,
+				 target_max - target_min);
+	target_val = DIV_ROUND_CLOSEST_ULL(target_val, source_max - source_min);
+	target_val += target_min;
+
+	return target_val;
+}
+
+/* Scale user_level in range [0..user_max] to [hw_min..hw_max]. */
+static inline u32 scale_user_to_hw(struct intel_connector *connector,
+				   u32 user_level, u32 user_max)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	return scale(user_level, 0, user_max,
+		     panel->backlight.min, panel->backlight.max);
+}
+
+/* Scale user_level in range [0..user_max] to [0..hw_max], clamping the result
+ * to [hw_min..hw_max]. */
+static inline u32 clamp_user_to_hw(struct intel_connector *connector,
+				   u32 user_level, u32 user_max)
+{
+	struct intel_panel *panel = &connector->panel;
+	u32 hw_level;
+
+	hw_level = scale(user_level, 0, user_max, 0, panel->backlight.max);
+	hw_level = clamp(hw_level, panel->backlight.min, panel->backlight.max);
+
+	return hw_level;
+}
+
+/* Scale hw_level in range [hw_min..hw_max] to [0..user_max]. */
+static inline u32 scale_hw_to_user(struct intel_connector *connector,
+				   u32 hw_level, u32 user_max)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	return scale(hw_level, panel->backlight.min, panel->backlight.max,
+		     0, user_max);
+}
+
+static u32 intel_panel_compute_brightness(struct intel_connector *connector,
+					  u32 val)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	WARN_ON(panel->backlight.max == 0);
+
+	if (i915_modparams.invert_brightness < 0)
+		return val;
+
+	if (i915_modparams.invert_brightness > 0 ||
+	    dev_priv->quirks & QUIRK_INVERT_BRIGHTNESS) {
+		return panel->backlight.max - val + panel->backlight.min;
+	}
+
+	return val;
+}
+
+static u32 lpt_get_backlight(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	return I915_READ(BLC_PWM_PCH_CTL2) & BACKLIGHT_DUTY_CYCLE_MASK;
+}
+
+static u32 pch_get_backlight(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	return I915_READ(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
+}
+
+static u32 i9xx_get_backlight(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 val;
+
+	val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
+	if (INTEL_GEN(dev_priv) < 4)
+		val >>= 1;
+
+	if (panel->backlight.combination_mode) {
+		u8 lbpc;
+
+		pci_read_config_byte(dev_priv->drm.pdev, LBPC, &lbpc);
+		val *= lbpc;
+	}
+
+	return val;
+}
+
+static u32 _vlv_get_backlight(struct drm_i915_private *dev_priv, enum pipe pipe)
+{
+	if (WARN_ON(pipe != PIPE_A && pipe != PIPE_B))
+		return 0;
+
+	return I915_READ(VLV_BLC_PWM_CTL(pipe)) & BACKLIGHT_DUTY_CYCLE_MASK;
+}
+
+static u32 vlv_get_backlight(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	enum pipe pipe = intel_connector_get_pipe(connector);
+
+	return _vlv_get_backlight(dev_priv, pipe);
+}
+
+static u32 bxt_get_backlight(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	return I915_READ(BXT_BLC_PWM_DUTY(panel->backlight.controller));
+}
+
+static u32 pwm_get_backlight(struct intel_connector *connector)
+{
+	struct intel_panel *panel = &connector->panel;
+	int duty_ns;
+
+	duty_ns = pwm_get_duty_cycle(panel->backlight.pwm);
+	return DIV_ROUND_UP(duty_ns * 100, CRC_PMIC_PWM_PERIOD_NS);
+}
+
+static void lpt_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	u32 val = I915_READ(BLC_PWM_PCH_CTL2) & ~BACKLIGHT_DUTY_CYCLE_MASK;
+	I915_WRITE(BLC_PWM_PCH_CTL2, val | level);
+}
+
+static void pch_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	u32 tmp;
+
+	tmp = I915_READ(BLC_PWM_CPU_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
+	I915_WRITE(BLC_PWM_CPU_CTL, tmp | level);
+}
+
+static void i9xx_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 tmp, mask;
+
+	WARN_ON(panel->backlight.max == 0);
+
+	if (panel->backlight.combination_mode) {
+		u8 lbpc;
+
+		lbpc = level * 0xfe / panel->backlight.max + 1;
+		level /= lbpc;
+		pci_write_config_byte(dev_priv->drm.pdev, LBPC, lbpc);
+	}
+
+	if (IS_GEN(dev_priv, 4)) {
+		mask = BACKLIGHT_DUTY_CYCLE_MASK;
+	} else {
+		level <<= 1;
+		mask = BACKLIGHT_DUTY_CYCLE_MASK_PNV;
+	}
+
+	tmp = I915_READ(BLC_PWM_CTL) & ~mask;
+	I915_WRITE(BLC_PWM_CTL, tmp | level);
+}
+
+static void vlv_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	enum pipe pipe = to_intel_crtc(conn_state->crtc)->pipe;
+	u32 tmp;
+
+	tmp = I915_READ(VLV_BLC_PWM_CTL(pipe)) & ~BACKLIGHT_DUTY_CYCLE_MASK;
+	I915_WRITE(VLV_BLC_PWM_CTL(pipe), tmp | level);
+}
+
+static void bxt_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	I915_WRITE(BXT_BLC_PWM_DUTY(panel->backlight.controller), level);
+}
+
+static void pwm_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_panel *panel = &to_intel_connector(conn_state->connector)->panel;
+	int duty_ns = DIV_ROUND_UP(level * CRC_PMIC_PWM_PERIOD_NS, 100);
+
+	pwm_config(panel->backlight.pwm, duty_ns, CRC_PMIC_PWM_PERIOD_NS);
+}
+
+static void
+intel_panel_actually_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	DRM_DEBUG_DRIVER("set backlight PWM = %d\n", level);
+
+	level = intel_panel_compute_brightness(connector, level);
+	panel->backlight.set(conn_state, level);
+}
+
+/* set backlight brightness to level in range [0..max], assuming hw min is
+ * respected.
+ */
+void intel_panel_set_backlight_acpi(const struct drm_connector_state *conn_state,
+				    u32 user_level, u32 user_max)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 hw_level;
+
+	/*
+	 * Lack of crtc may occur during driver init because
+	 * connection_mutex isn't held across the entire backlight
+	 * setup + modeset readout, and the BIOS can issue the
+	 * requests at any time.
+	 */
+	if (!panel->backlight.present || !conn_state->crtc)
+		return;
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	WARN_ON(panel->backlight.max == 0);
+
+	hw_level = clamp_user_to_hw(connector, user_level, user_max);
+	panel->backlight.level = hw_level;
+
+	if (panel->backlight.device)
+		panel->backlight.device->props.brightness =
+			scale_hw_to_user(connector,
+					 panel->backlight.level,
+					 panel->backlight.device->props.max_brightness);
+
+	if (panel->backlight.enabled)
+		intel_panel_actually_set_backlight(conn_state, hw_level);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+static void lpt_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	u32 tmp;
+
+	intel_panel_actually_set_backlight(old_conn_state, 0);
+
+	/*
+	 * Although we don't support or enable CPU PWM with LPT/SPT based
+	 * systems, it may have been enabled prior to loading the
+	 * driver. Disable to avoid warnings on LCPLL disable.
+	 *
+	 * This needs rework if we need to add support for CPU PWM on PCH split
+	 * platforms.
+	 */
+	tmp = I915_READ(BLC_PWM_CPU_CTL2);
+	if (tmp & BLM_PWM_ENABLE) {
+		DRM_DEBUG_KMS("cpu backlight was enabled, disabling\n");
+		I915_WRITE(BLC_PWM_CPU_CTL2, tmp & ~BLM_PWM_ENABLE);
+	}
+
+	tmp = I915_READ(BLC_PWM_PCH_CTL1);
+	I915_WRITE(BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE);
+}
+
+static void pch_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	u32 tmp;
+
+	intel_panel_actually_set_backlight(old_conn_state, 0);
+
+	tmp = I915_READ(BLC_PWM_CPU_CTL2);
+	I915_WRITE(BLC_PWM_CPU_CTL2, tmp & ~BLM_PWM_ENABLE);
+
+	tmp = I915_READ(BLC_PWM_PCH_CTL1);
+	I915_WRITE(BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE);
+}
+
+static void i9xx_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	intel_panel_actually_set_backlight(old_conn_state, 0);
+}
+
+static void i965_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	struct drm_i915_private *dev_priv = to_i915(old_conn_state->connector->dev);
+	u32 tmp;
+
+	intel_panel_actually_set_backlight(old_conn_state, 0);
+
+	tmp = I915_READ(BLC_PWM_CTL2);
+	I915_WRITE(BLC_PWM_CTL2, tmp & ~BLM_PWM_ENABLE);
+}
+
+static void vlv_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	enum pipe pipe = to_intel_crtc(old_conn_state->crtc)->pipe;
+	u32 tmp;
+
+	intel_panel_actually_set_backlight(old_conn_state, 0);
+
+	tmp = I915_READ(VLV_BLC_PWM_CTL2(pipe));
+	I915_WRITE(VLV_BLC_PWM_CTL2(pipe), tmp & ~BLM_PWM_ENABLE);
+}
+
+static void bxt_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 tmp, val;
+
+	intel_panel_actually_set_backlight(old_conn_state, 0);
+
+	tmp = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+	I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller),
+			tmp & ~BXT_BLC_PWM_ENABLE);
+
+	if (panel->backlight.controller == 1) {
+		val = I915_READ(UTIL_PIN_CTL);
+		val &= ~UTIL_PIN_ENABLE;
+		I915_WRITE(UTIL_PIN_CTL, val);
+	}
+}
+
+static void cnp_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 tmp;
+
+	intel_panel_actually_set_backlight(old_conn_state, 0);
+
+	tmp = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+	I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller),
+		   tmp & ~BXT_BLC_PWM_ENABLE);
+}
+
+static void pwm_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	/* Disable the backlight */
+	intel_panel_actually_set_backlight(old_conn_state, 0);
+	usleep_range(2000, 3000);
+	pwm_disable(panel->backlight.pwm);
+}
+
+void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	if (!panel->backlight.present)
+		return;
+
+	/*
+	 * Do not disable backlight on the vga_switcheroo path. When switching
+	 * away from i915, the other client may depend on i915 to handle the
+	 * backlight. This will leave the backlight on unnecessarily when
+	 * another client is not activated.
+	 */
+	if (dev_priv->drm.switch_power_state == DRM_SWITCH_POWER_CHANGING) {
+		DRM_DEBUG_DRIVER("Skipping backlight disable on vga switch\n");
+		return;
+	}
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	if (panel->backlight.device)
+		panel->backlight.device->props.power = FB_BLANK_POWERDOWN;
+	panel->backlight.enabled = false;
+	panel->backlight.disable(old_conn_state);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+static void lpt_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 pch_ctl1, pch_ctl2, schicken;
+
+	pch_ctl1 = I915_READ(BLC_PWM_PCH_CTL1);
+	if (pch_ctl1 & BLM_PCH_PWM_ENABLE) {
+		DRM_DEBUG_KMS("pch backlight already enabled\n");
+		pch_ctl1 &= ~BLM_PCH_PWM_ENABLE;
+		I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1);
+	}
+
+	if (HAS_PCH_LPT(dev_priv)) {
+		schicken = I915_READ(SOUTH_CHICKEN2);
+		if (panel->backlight.alternate_pwm_increment)
+			schicken |= LPT_PWM_GRANULARITY;
+		else
+			schicken &= ~LPT_PWM_GRANULARITY;
+		I915_WRITE(SOUTH_CHICKEN2, schicken);
+	} else {
+		schicken = I915_READ(SOUTH_CHICKEN1);
+		if (panel->backlight.alternate_pwm_increment)
+			schicken |= SPT_PWM_GRANULARITY;
+		else
+			schicken &= ~SPT_PWM_GRANULARITY;
+		I915_WRITE(SOUTH_CHICKEN1, schicken);
+	}
+
+	pch_ctl2 = panel->backlight.max << 16;
+	I915_WRITE(BLC_PWM_PCH_CTL2, pch_ctl2);
+
+	pch_ctl1 = 0;
+	if (panel->backlight.active_low_pwm)
+		pch_ctl1 |= BLM_PCH_POLARITY;
+
+	/* After LPT, override is the default. */
+	if (HAS_PCH_LPT(dev_priv))
+		pch_ctl1 |= BLM_PCH_OVERRIDE_ENABLE;
+
+	I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1);
+	POSTING_READ(BLC_PWM_PCH_CTL1);
+	I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1 | BLM_PCH_PWM_ENABLE);
+
+	/* This won't stick until the above enable. */
+	intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
+}
+
+static void pch_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
+	u32 cpu_ctl2, pch_ctl1, pch_ctl2;
+
+	cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
+	if (cpu_ctl2 & BLM_PWM_ENABLE) {
+		DRM_DEBUG_KMS("cpu backlight already enabled\n");
+		cpu_ctl2 &= ~BLM_PWM_ENABLE;
+		I915_WRITE(BLC_PWM_CPU_CTL2, cpu_ctl2);
+	}
+
+	pch_ctl1 = I915_READ(BLC_PWM_PCH_CTL1);
+	if (pch_ctl1 & BLM_PCH_PWM_ENABLE) {
+		DRM_DEBUG_KMS("pch backlight already enabled\n");
+		pch_ctl1 &= ~BLM_PCH_PWM_ENABLE;
+		I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1);
+	}
+
+	if (cpu_transcoder == TRANSCODER_EDP)
+		cpu_ctl2 = BLM_TRANSCODER_EDP;
+	else
+		cpu_ctl2 = BLM_PIPE(cpu_transcoder);
+	I915_WRITE(BLC_PWM_CPU_CTL2, cpu_ctl2);
+	POSTING_READ(BLC_PWM_CPU_CTL2);
+	I915_WRITE(BLC_PWM_CPU_CTL2, cpu_ctl2 | BLM_PWM_ENABLE);
+
+	/* This won't stick until the above enable. */
+	intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
+
+	pch_ctl2 = panel->backlight.max << 16;
+	I915_WRITE(BLC_PWM_PCH_CTL2, pch_ctl2);
+
+	pch_ctl1 = 0;
+	if (panel->backlight.active_low_pwm)
+		pch_ctl1 |= BLM_PCH_POLARITY;
+
+	I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1);
+	POSTING_READ(BLC_PWM_PCH_CTL1);
+	I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1 | BLM_PCH_PWM_ENABLE);
+}
+
+static void i9xx_enable_backlight(const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 ctl, freq;
+
+	ctl = I915_READ(BLC_PWM_CTL);
+	if (ctl & BACKLIGHT_DUTY_CYCLE_MASK_PNV) {
+		DRM_DEBUG_KMS("backlight already enabled\n");
+		I915_WRITE(BLC_PWM_CTL, 0);
+	}
+
+	freq = panel->backlight.max;
+	if (panel->backlight.combination_mode)
+		freq /= 0xff;
+
+	ctl = freq << 17;
+	if (panel->backlight.combination_mode)
+		ctl |= BLM_LEGACY_MODE;
+	if (IS_PINEVIEW(dev_priv) && panel->backlight.active_low_pwm)
+		ctl |= BLM_POLARITY_PNV;
+
+	I915_WRITE(BLC_PWM_CTL, ctl);
+	POSTING_READ(BLC_PWM_CTL);
+
+	/* XXX: combine this into above write? */
+	intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
+
+	/*
+	 * Needed to enable backlight on some 855gm models. BLC_HIST_CTL is
+	 * 855gm only, but checking for gen2 is safe, as 855gm is the only gen2
+	 * that has backlight.
+	 */
+	if (IS_GEN(dev_priv, 2))
+		I915_WRITE(BLC_HIST_CTL, BLM_HISTOGRAM_ENABLE);
+}
+
+static void i965_enable_backlight(const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = to_intel_crtc(conn_state->crtc)->pipe;
+	u32 ctl, ctl2, freq;
+
+	ctl2 = I915_READ(BLC_PWM_CTL2);
+	if (ctl2 & BLM_PWM_ENABLE) {
+		DRM_DEBUG_KMS("backlight already enabled\n");
+		ctl2 &= ~BLM_PWM_ENABLE;
+		I915_WRITE(BLC_PWM_CTL2, ctl2);
+	}
+
+	freq = panel->backlight.max;
+	if (panel->backlight.combination_mode)
+		freq /= 0xff;
+
+	ctl = freq << 16;
+	I915_WRITE(BLC_PWM_CTL, ctl);
+
+	ctl2 = BLM_PIPE(pipe);
+	if (panel->backlight.combination_mode)
+		ctl2 |= BLM_COMBINATION_MODE;
+	if (panel->backlight.active_low_pwm)
+		ctl2 |= BLM_POLARITY_I965;
+	I915_WRITE(BLC_PWM_CTL2, ctl2);
+	POSTING_READ(BLC_PWM_CTL2);
+	I915_WRITE(BLC_PWM_CTL2, ctl2 | BLM_PWM_ENABLE);
+
+	intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
+}
+
+static void vlv_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = to_intel_crtc(crtc_state->base.crtc)->pipe;
+	u32 ctl, ctl2;
+
+	ctl2 = I915_READ(VLV_BLC_PWM_CTL2(pipe));
+	if (ctl2 & BLM_PWM_ENABLE) {
+		DRM_DEBUG_KMS("backlight already enabled\n");
+		ctl2 &= ~BLM_PWM_ENABLE;
+		I915_WRITE(VLV_BLC_PWM_CTL2(pipe), ctl2);
+	}
+
+	ctl = panel->backlight.max << 16;
+	I915_WRITE(VLV_BLC_PWM_CTL(pipe), ctl);
+
+	/* XXX: combine this into above write? */
+	intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
+
+	ctl2 = 0;
+	if (panel->backlight.active_low_pwm)
+		ctl2 |= BLM_POLARITY_I965;
+	I915_WRITE(VLV_BLC_PWM_CTL2(pipe), ctl2);
+	POSTING_READ(VLV_BLC_PWM_CTL2(pipe));
+	I915_WRITE(VLV_BLC_PWM_CTL2(pipe), ctl2 | BLM_PWM_ENABLE);
+}
+
+static void bxt_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = to_intel_crtc(crtc_state->base.crtc)->pipe;
+	u32 pwm_ctl, val;
+
+	/* Controller 1 uses the utility pin. */
+	if (panel->backlight.controller == 1) {
+		val = I915_READ(UTIL_PIN_CTL);
+		if (val & UTIL_PIN_ENABLE) {
+			DRM_DEBUG_KMS("util pin already enabled\n");
+			val &= ~UTIL_PIN_ENABLE;
+			I915_WRITE(UTIL_PIN_CTL, val);
+		}
+
+		val = 0;
+		if (panel->backlight.util_pin_active_low)
+			val |= UTIL_PIN_POLARITY;
+		I915_WRITE(UTIL_PIN_CTL, val | UTIL_PIN_PIPE(pipe) |
+				UTIL_PIN_MODE_PWM | UTIL_PIN_ENABLE);
+	}
+
+	pwm_ctl = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+	if (pwm_ctl & BXT_BLC_PWM_ENABLE) {
+		DRM_DEBUG_KMS("backlight already enabled\n");
+		pwm_ctl &= ~BXT_BLC_PWM_ENABLE;
+		I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller),
+				pwm_ctl);
+	}
+
+	I915_WRITE(BXT_BLC_PWM_FREQ(panel->backlight.controller),
+			panel->backlight.max);
+
+	intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
+
+	pwm_ctl = 0;
+	if (panel->backlight.active_low_pwm)
+		pwm_ctl |= BXT_BLC_PWM_POLARITY;
+
+	I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller), pwm_ctl);
+	POSTING_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+	I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller),
+			pwm_ctl | BXT_BLC_PWM_ENABLE);
+}
+
+static void cnp_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 pwm_ctl;
+
+	pwm_ctl = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+	if (pwm_ctl & BXT_BLC_PWM_ENABLE) {
+		DRM_DEBUG_KMS("backlight already enabled\n");
+		pwm_ctl &= ~BXT_BLC_PWM_ENABLE;
+		I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller),
+			   pwm_ctl);
+	}
+
+	I915_WRITE(BXT_BLC_PWM_FREQ(panel->backlight.controller),
+		   panel->backlight.max);
+
+	intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
+
+	pwm_ctl = 0;
+	if (panel->backlight.active_low_pwm)
+		pwm_ctl |= BXT_BLC_PWM_POLARITY;
+
+	I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller), pwm_ctl);
+	POSTING_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+	I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller),
+		   pwm_ctl | BXT_BLC_PWM_ENABLE);
+}
+
+static void pwm_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	pwm_enable(panel->backlight.pwm);
+	intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
+}
+
+static void __intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
+					   const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	WARN_ON(panel->backlight.max == 0);
+
+	if (panel->backlight.level <= panel->backlight.min) {
+		panel->backlight.level = panel->backlight.max;
+		if (panel->backlight.device)
+			panel->backlight.device->props.brightness =
+				scale_hw_to_user(connector,
+						 panel->backlight.level,
+						 panel->backlight.device->props.max_brightness);
+	}
+
+	panel->backlight.enable(crtc_state, conn_state);
+	panel->backlight.enabled = true;
+	if (panel->backlight.device)
+		panel->backlight.device->props.power = FB_BLANK_UNBLANK;
+}
+
+void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = to_intel_crtc(crtc_state->base.crtc)->pipe;
+
+	if (!panel->backlight.present)
+		return;
+
+	DRM_DEBUG_KMS("pipe %c\n", pipe_name(pipe));
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	__intel_panel_enable_backlight(crtc_state, conn_state);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+static u32 intel_panel_get_backlight(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 val = 0;
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	if (panel->backlight.enabled) {
+		val = panel->backlight.get(connector);
+		val = intel_panel_compute_brightness(connector, val);
+	}
+
+	mutex_unlock(&dev_priv->backlight_lock);
+
+	DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val);
+	return val;
+}
+
+/* set backlight brightness to level in range [0..max], scaling wrt hw min */
+static void intel_panel_set_backlight(const struct drm_connector_state *conn_state,
+				      u32 user_level, u32 user_max)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 hw_level;
+
+	if (!panel->backlight.present)
+		return;
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	WARN_ON(panel->backlight.max == 0);
+
+	hw_level = scale_user_to_hw(connector, user_level, user_max);
+	panel->backlight.level = hw_level;
+
+	if (panel->backlight.enabled)
+		intel_panel_actually_set_backlight(conn_state, hw_level);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+static int intel_backlight_device_update_status(struct backlight_device *bd)
+{
+	struct intel_connector *connector = bl_get_data(bd);
+	struct intel_panel *panel = &connector->panel;
+	struct drm_device *dev = connector->base.dev;
+
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+	DRM_DEBUG_KMS("updating intel_backlight, brightness=%d/%d\n",
+		      bd->props.brightness, bd->props.max_brightness);
+	intel_panel_set_backlight(connector->base.state, bd->props.brightness,
+				  bd->props.max_brightness);
+
+	/*
+	 * Allow flipping bl_power as a sub-state of enabled. Sadly the
+	 * backlight class device does not make it easy to to differentiate
+	 * between callbacks for brightness and bl_power, so our backlight_power
+	 * callback needs to take this into account.
+	 */
+	if (panel->backlight.enabled) {
+		if (panel->backlight.power) {
+			bool enable = bd->props.power == FB_BLANK_UNBLANK &&
+				bd->props.brightness != 0;
+			panel->backlight.power(connector, enable);
+		}
+	} else {
+		bd->props.power = FB_BLANK_POWERDOWN;
+	}
+
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
+	return 0;
+}
+
+static int intel_backlight_device_get_brightness(struct backlight_device *bd)
+{
+	struct intel_connector *connector = bl_get_data(bd);
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	intel_wakeref_t wakeref;
+	int ret = 0;
+
+	with_intel_runtime_pm(&dev_priv->runtime_pm, wakeref) {
+		u32 hw_level;
+
+		drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+
+		hw_level = intel_panel_get_backlight(connector);
+		ret = scale_hw_to_user(connector,
+				       hw_level, bd->props.max_brightness);
+
+		drm_modeset_unlock(&dev->mode_config.connection_mutex);
+	}
+
+	return ret;
+}
+
+static const struct backlight_ops intel_backlight_device_ops = {
+	.update_status = intel_backlight_device_update_status,
+	.get_brightness = intel_backlight_device_get_brightness,
+};
+
+int intel_backlight_device_register(struct intel_connector *connector)
+{
+	struct intel_panel *panel = &connector->panel;
+	struct backlight_properties props;
+
+	if (WARN_ON(panel->backlight.device))
+		return -ENODEV;
+
+	if (!panel->backlight.present)
+		return 0;
+
+	WARN_ON(panel->backlight.max == 0);
+
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_RAW;
+
+	/*
+	 * Note: Everything should work even if the backlight device max
+	 * presented to the userspace is arbitrarily chosen.
+	 */
+	props.max_brightness = panel->backlight.max;
+	props.brightness = scale_hw_to_user(connector,
+					    panel->backlight.level,
+					    props.max_brightness);
+
+	if (panel->backlight.enabled)
+		props.power = FB_BLANK_UNBLANK;
+	else
+		props.power = FB_BLANK_POWERDOWN;
+
+	/*
+	 * Note: using the same name independent of the connector prevents
+	 * registration of multiple backlight devices in the driver.
+	 */
+	panel->backlight.device =
+		backlight_device_register("intel_backlight",
+					  connector->base.kdev,
+					  connector,
+					  &intel_backlight_device_ops, &props);
+
+	if (IS_ERR(panel->backlight.device)) {
+		DRM_ERROR("Failed to register backlight: %ld\n",
+			  PTR_ERR(panel->backlight.device));
+		panel->backlight.device = NULL;
+		return -ENODEV;
+	}
+
+	DRM_DEBUG_KMS("Connector %s backlight sysfs interface registered\n",
+		      connector->base.name);
+
+	return 0;
+}
+
+void intel_backlight_device_unregister(struct intel_connector *connector)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	if (panel->backlight.device) {
+		backlight_device_unregister(panel->backlight.device);
+		panel->backlight.device = NULL;
+	}
+}
+#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
+
+/*
+ * CNP: PWM clock frequency is 19.2 MHz or 24 MHz.
+ *      PWM increment = 1
+ */
+static u32 cnp_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	return DIV_ROUND_CLOSEST(KHz(dev_priv->rawclk_freq), pwm_freq_hz);
+}
+
+/*
+ * BXT: PWM clock frequency = 19.2 MHz.
+ */
+static u32 bxt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	return DIV_ROUND_CLOSEST(KHz(19200), pwm_freq_hz);
+}
+
+/*
+ * SPT: This value represents the period of the PWM stream in clock periods
+ * multiplied by 16 (default increment) or 128 (alternate increment selected in
+ * SCHICKEN_1 bit 0). PWM clock is 24 MHz.
+ */
+static u32 spt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct intel_panel *panel = &connector->panel;
+	u32 mul;
+
+	if (panel->backlight.alternate_pwm_increment)
+		mul = 128;
+	else
+		mul = 16;
+
+	return DIV_ROUND_CLOSEST(MHz(24), pwm_freq_hz * mul);
+}
+
+/*
+ * LPT: This value represents the period of the PWM stream in clock periods
+ * multiplied by 128 (default increment) or 16 (alternate increment, selected in
+ * LPT SOUTH_CHICKEN2 register bit 5).
+ */
+static u32 lpt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 mul, clock;
+
+	if (panel->backlight.alternate_pwm_increment)
+		mul = 16;
+	else
+		mul = 128;
+
+	if (HAS_PCH_LPT_H(dev_priv))
+		clock = MHz(135); /* LPT:H */
+	else
+		clock = MHz(24); /* LPT:LP */
+
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);
+}
+
+/*
+ * ILK/SNB/IVB: This value represents the period of the PWM stream in PCH
+ * display raw clocks multiplied by 128.
+ */
+static u32 pch_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	return DIV_ROUND_CLOSEST(KHz(dev_priv->rawclk_freq), pwm_freq_hz * 128);
+}
+
+/*
+ * Gen2: This field determines the number of time base events (display core
+ * clock frequency/32) in total for a complete cycle of modulated backlight
+ * control.
+ *
+ * Gen3: A time base event equals the display core clock ([DevPNV] HRAW clock)
+ * divided by 32.
+ */
+static u32 i9xx_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	int clock;
+
+	if (IS_PINEVIEW(dev_priv))
+		clock = KHz(dev_priv->rawclk_freq);
+	else
+		clock = KHz(dev_priv->cdclk.hw.cdclk);
+
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 32);
+}
+
+/*
+ * Gen4: This value represents the period of the PWM stream in display core
+ * clocks ([DevCTG] HRAW clocks) multiplied by 128.
+ *
+ */
+static u32 i965_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	int clock;
+
+	if (IS_G4X(dev_priv))
+		clock = KHz(dev_priv->rawclk_freq);
+	else
+		clock = KHz(dev_priv->cdclk.hw.cdclk);
+
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 128);
+}
+
+/*
+ * VLV: This value represents the period of the PWM stream in display core
+ * clocks ([DevCTG] 200MHz HRAW clocks) multiplied by 128 or 25MHz S0IX clocks
+ * multiplied by 16. CHV uses a 19.2MHz S0IX clock.
+ */
+static u32 vlv_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	int mul, clock;
+
+	if ((I915_READ(CBR1_VLV) & CBR_PWM_CLOCK_MUX_SELECT) == 0) {
+		if (IS_CHERRYVIEW(dev_priv))
+			clock = KHz(19200);
+		else
+			clock = MHz(25);
+		mul = 16;
+	} else {
+		clock = KHz(dev_priv->rawclk_freq);
+		mul = 128;
+	}
+
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);
+}
+
+static u32 get_backlight_max_vbt(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u16 pwm_freq_hz = dev_priv->vbt.backlight.pwm_freq_hz;
+	u32 pwm;
+
+	if (!panel->backlight.hz_to_pwm) {
+		DRM_DEBUG_KMS("backlight frequency conversion not supported\n");
+		return 0;
+	}
+
+	if (pwm_freq_hz) {
+		DRM_DEBUG_KMS("VBT defined backlight frequency %u Hz\n",
+			      pwm_freq_hz);
+	} else {
+		pwm_freq_hz = 200;
+		DRM_DEBUG_KMS("default backlight frequency %u Hz\n",
+			      pwm_freq_hz);
+	}
+
+	pwm = panel->backlight.hz_to_pwm(connector, pwm_freq_hz);
+	if (!pwm) {
+		DRM_DEBUG_KMS("backlight frequency conversion failed\n");
+		return 0;
+	}
+
+	return pwm;
+}
+
+/*
+ * Note: The setup hooks can't assume pipe is set!
+ */
+static u32 get_backlight_min_vbt(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	int min;
+
+	WARN_ON(panel->backlight.max == 0);
+
+	/*
+	 * XXX: If the vbt value is 255, it makes min equal to max, which leads
+	 * to problems. There are such machines out there. Either our
+	 * interpretation is wrong or the vbt has bogus data. Or both. Safeguard
+	 * against this by letting the minimum be at most (arbitrarily chosen)
+	 * 25% of the max.
+	 */
+	min = clamp_t(int, dev_priv->vbt.backlight.min_brightness, 0, 64);
+	if (min != dev_priv->vbt.backlight.min_brightness) {
+		DRM_DEBUG_KMS("clamping VBT min backlight %d/255 to %d/255\n",
+			      dev_priv->vbt.backlight.min_brightness, min);
+	}
+
+	/* vbt value is a coefficient in range [0..255] */
+	return scale(min, 0, 255, 0, panel->backlight.max);
+}
+
+static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 cpu_ctl2, pch_ctl1, pch_ctl2, val;
+	bool alt, cpu_mode;
+
+	if (HAS_PCH_LPT(dev_priv))
+		alt = I915_READ(SOUTH_CHICKEN2) & LPT_PWM_GRANULARITY;
+	else
+		alt = I915_READ(SOUTH_CHICKEN1) & SPT_PWM_GRANULARITY;
+	panel->backlight.alternate_pwm_increment = alt;
+
+	pch_ctl1 = I915_READ(BLC_PWM_PCH_CTL1);
+	panel->backlight.active_low_pwm = pch_ctl1 & BLM_PCH_POLARITY;
+
+	pch_ctl2 = I915_READ(BLC_PWM_PCH_CTL2);
+	panel->backlight.max = pch_ctl2 >> 16;
+
+	cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.max)
+		return -ENODEV;
+
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
+	panel->backlight.enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE;
+
+	cpu_mode = panel->backlight.enabled && HAS_PCH_LPT(dev_priv) &&
+		   !(pch_ctl1 & BLM_PCH_OVERRIDE_ENABLE) &&
+		   (cpu_ctl2 & BLM_PWM_ENABLE);
+	if (cpu_mode)
+		val = pch_get_backlight(connector);
+	else
+		val = lpt_get_backlight(connector);
+	val = intel_panel_compute_brightness(connector, val);
+	panel->backlight.level = clamp(val, panel->backlight.min,
+				       panel->backlight.max);
+
+	if (cpu_mode) {
+		DRM_DEBUG_KMS("CPU backlight register was enabled, switching to PCH override\n");
+
+		/* Write converted CPU PWM value to PCH override register */
+		lpt_set_backlight(connector->base.state, panel->backlight.level);
+		I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1 | BLM_PCH_OVERRIDE_ENABLE);
+
+		I915_WRITE(BLC_PWM_CPU_CTL2, cpu_ctl2 & ~BLM_PWM_ENABLE);
+	}
+
+	return 0;
+}
+
+static int pch_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 cpu_ctl2, pch_ctl1, pch_ctl2, val;
+
+	pch_ctl1 = I915_READ(BLC_PWM_PCH_CTL1);
+	panel->backlight.active_low_pwm = pch_ctl1 & BLM_PCH_POLARITY;
+
+	pch_ctl2 = I915_READ(BLC_PWM_PCH_CTL2);
+	panel->backlight.max = pch_ctl2 >> 16;
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.max)
+		return -ENODEV;
+
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
+	val = pch_get_backlight(connector);
+	val = intel_panel_compute_brightness(connector, val);
+	panel->backlight.level = clamp(val, panel->backlight.min,
+				       panel->backlight.max);
+
+	cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
+	panel->backlight.enabled = (cpu_ctl2 & BLM_PWM_ENABLE) &&
+		(pch_ctl1 & BLM_PCH_PWM_ENABLE);
+
+	return 0;
+}
+
+static int i9xx_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 ctl, val;
+
+	ctl = I915_READ(BLC_PWM_CTL);
+
+	if (IS_GEN(dev_priv, 2) || IS_I915GM(dev_priv) || IS_I945GM(dev_priv))
+		panel->backlight.combination_mode = ctl & BLM_LEGACY_MODE;
+
+	if (IS_PINEVIEW(dev_priv))
+		panel->backlight.active_low_pwm = ctl & BLM_POLARITY_PNV;
+
+	panel->backlight.max = ctl >> 17;
+
+	if (!panel->backlight.max) {
+		panel->backlight.max = get_backlight_max_vbt(connector);
+		panel->backlight.max >>= 1;
+	}
+
+	if (!panel->backlight.max)
+		return -ENODEV;
+
+	if (panel->backlight.combination_mode)
+		panel->backlight.max *= 0xff;
+
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
+	val = i9xx_get_backlight(connector);
+	val = intel_panel_compute_brightness(connector, val);
+	panel->backlight.level = clamp(val, panel->backlight.min,
+				       panel->backlight.max);
+
+	panel->backlight.enabled = val != 0;
+
+	return 0;
+}
+
+static int i965_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 ctl, ctl2, val;
+
+	ctl2 = I915_READ(BLC_PWM_CTL2);
+	panel->backlight.combination_mode = ctl2 & BLM_COMBINATION_MODE;
+	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
+
+	ctl = I915_READ(BLC_PWM_CTL);
+	panel->backlight.max = ctl >> 16;
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.max)
+		return -ENODEV;
+
+	if (panel->backlight.combination_mode)
+		panel->backlight.max *= 0xff;
+
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
+	val = i9xx_get_backlight(connector);
+	val = intel_panel_compute_brightness(connector, val);
+	panel->backlight.level = clamp(val, panel->backlight.min,
+				       panel->backlight.max);
+
+	panel->backlight.enabled = ctl2 & BLM_PWM_ENABLE;
+
+	return 0;
+}
+
+static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 ctl, ctl2, val;
+
+	if (WARN_ON(pipe != PIPE_A && pipe != PIPE_B))
+		return -ENODEV;
+
+	ctl2 = I915_READ(VLV_BLC_PWM_CTL2(pipe));
+	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
+
+	ctl = I915_READ(VLV_BLC_PWM_CTL(pipe));
+	panel->backlight.max = ctl >> 16;
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.max)
+		return -ENODEV;
+
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
+	val = _vlv_get_backlight(dev_priv, pipe);
+	val = intel_panel_compute_brightness(connector, val);
+	panel->backlight.level = clamp(val, panel->backlight.min,
+				       panel->backlight.max);
+
+	panel->backlight.enabled = ctl2 & BLM_PWM_ENABLE;
+
+	return 0;
+}
+
+static int
+bxt_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 pwm_ctl, val;
+
+	panel->backlight.controller = dev_priv->vbt.backlight.controller;
+
+	pwm_ctl = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+
+	/* Controller 1 uses the utility pin. */
+	if (panel->backlight.controller == 1) {
+		val = I915_READ(UTIL_PIN_CTL);
+		panel->backlight.util_pin_active_low =
+					val & UTIL_PIN_POLARITY;
+	}
+
+	panel->backlight.active_low_pwm = pwm_ctl & BXT_BLC_PWM_POLARITY;
+	panel->backlight.max =
+		I915_READ(BXT_BLC_PWM_FREQ(panel->backlight.controller));
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.max)
+		return -ENODEV;
+
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
+	val = bxt_get_backlight(connector);
+	val = intel_panel_compute_brightness(connector, val);
+	panel->backlight.level = clamp(val, panel->backlight.min,
+				       panel->backlight.max);
+
+	panel->backlight.enabled = pwm_ctl & BXT_BLC_PWM_ENABLE;
+
+	return 0;
+}
+
+static int
+cnp_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 pwm_ctl, val;
+
+	/*
+	 * CNP has the BXT implementation of backlight, but with only one
+	 * controller. TODO: ICP has multiple controllers but we only use
+	 * controller 0 for now.
+	 */
+	panel->backlight.controller = 0;
+
+	pwm_ctl = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+
+	panel->backlight.active_low_pwm = pwm_ctl & BXT_BLC_PWM_POLARITY;
+	panel->backlight.max =
+		I915_READ(BXT_BLC_PWM_FREQ(panel->backlight.controller));
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.max)
+		return -ENODEV;
+
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
+	val = bxt_get_backlight(connector);
+	val = intel_panel_compute_brightness(connector, val);
+	panel->backlight.level = clamp(val, panel->backlight.min,
+				       panel->backlight.max);
+
+	panel->backlight.enabled = pwm_ctl & BXT_BLC_PWM_ENABLE;
+
+	return 0;
+}
+
+static int pwm_setup_backlight(struct intel_connector *connector,
+			       enum pipe pipe)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct intel_panel *panel = &connector->panel;
+	int retval;
+
+	/* Get the PWM chip for backlight control */
+	panel->backlight.pwm = pwm_get(dev->dev, "pwm_backlight");
+	if (IS_ERR(panel->backlight.pwm)) {
+		DRM_ERROR("Failed to own the pwm chip\n");
+		panel->backlight.pwm = NULL;
+		return -ENODEV;
+	}
+
+	/*
+	 * FIXME: pwm_apply_args() should be removed when switching to
+	 * the atomic PWM API.
+	 */
+	pwm_apply_args(panel->backlight.pwm);
+
+	retval = pwm_config(panel->backlight.pwm, CRC_PMIC_PWM_PERIOD_NS,
+			    CRC_PMIC_PWM_PERIOD_NS);
+	if (retval < 0) {
+		DRM_ERROR("Failed to configure the pwm chip\n");
+		pwm_put(panel->backlight.pwm);
+		panel->backlight.pwm = NULL;
+		return retval;
+	}
+
+	panel->backlight.min = 0; /* 0% */
+	panel->backlight.max = 100; /* 100% */
+	panel->backlight.level = DIV_ROUND_UP(
+				 pwm_get_duty_cycle(panel->backlight.pwm) * 100,
+				 CRC_PMIC_PWM_PERIOD_NS);
+	panel->backlight.enabled = panel->backlight.level != 0;
+
+	return 0;
+}
+
+void intel_panel_update_backlight(struct intel_encoder *encoder,
+				  const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	if (!panel->backlight.present)
+		return;
+
+	mutex_lock(&dev_priv->backlight_lock);
+	if (!panel->backlight.enabled)
+		__intel_panel_enable_backlight(crtc_state, conn_state);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+int intel_panel_setup_backlight(struct drm_connector *connector, enum pipe pipe)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->dev);
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct intel_panel *panel = &intel_connector->panel;
+	int ret;
+
+	if (!dev_priv->vbt.backlight.present) {
+		if (dev_priv->quirks & QUIRK_BACKLIGHT_PRESENT) {
+			DRM_DEBUG_KMS("no backlight present per VBT, but present per quirk\n");
+		} else {
+			DRM_DEBUG_KMS("no backlight present per VBT\n");
+			return 0;
+		}
+	}
+
+	/* ensure intel_panel has been initialized first */
+	if (WARN_ON(!panel->backlight.setup))
+		return -ENODEV;
+
+	/* set level and max in panel struct */
+	mutex_lock(&dev_priv->backlight_lock);
+	ret = panel->backlight.setup(intel_connector, pipe);
+	mutex_unlock(&dev_priv->backlight_lock);
+
+	if (ret) {
+		DRM_DEBUG_KMS("failed to setup backlight for connector %s\n",
+			      connector->name);
+		return ret;
+	}
+
+	panel->backlight.present = true;
+
+	DRM_DEBUG_KMS("Connector %s backlight initialized, %s, brightness %u/%u\n",
+		      connector->name,
+		      enableddisabled(panel->backlight.enabled),
+		      panel->backlight.level, panel->backlight.max);
+
+	return 0;
+}
+
+static void intel_panel_destroy_backlight(struct intel_panel *panel)
+{
+	/* dispose of the pwm */
+	if (panel->backlight.pwm)
+		pwm_put(panel->backlight.pwm);
+
+	panel->backlight.present = false;
+}
+
+/* Set up chip specific backlight functions */
+static void
+intel_panel_init_backlight_funcs(struct intel_panel *panel)
+{
+	struct intel_connector *connector =
+		container_of(panel, struct intel_connector, panel);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	if (connector->base.connector_type == DRM_MODE_CONNECTOR_eDP &&
+	    intel_dp_aux_init_backlight_funcs(connector) == 0)
+		return;
+
+	if (connector->base.connector_type == DRM_MODE_CONNECTOR_DSI &&
+	    intel_dsi_dcs_init_backlight_funcs(connector) == 0)
+		return;
+
+	if (IS_GEN9_LP(dev_priv)) {
+		panel->backlight.setup = bxt_setup_backlight;
+		panel->backlight.enable = bxt_enable_backlight;
+		panel->backlight.disable = bxt_disable_backlight;
+		panel->backlight.set = bxt_set_backlight;
+		panel->backlight.get = bxt_get_backlight;
+		panel->backlight.hz_to_pwm = bxt_hz_to_pwm;
+	} else if (INTEL_PCH_TYPE(dev_priv) >= PCH_CNP) {
+		panel->backlight.setup = cnp_setup_backlight;
+		panel->backlight.enable = cnp_enable_backlight;
+		panel->backlight.disable = cnp_disable_backlight;
+		panel->backlight.set = bxt_set_backlight;
+		panel->backlight.get = bxt_get_backlight;
+		panel->backlight.hz_to_pwm = cnp_hz_to_pwm;
+	} else if (INTEL_PCH_TYPE(dev_priv) >= PCH_LPT) {
+		panel->backlight.setup = lpt_setup_backlight;
+		panel->backlight.enable = lpt_enable_backlight;
+		panel->backlight.disable = lpt_disable_backlight;
+		panel->backlight.set = lpt_set_backlight;
+		panel->backlight.get = lpt_get_backlight;
+		if (HAS_PCH_LPT(dev_priv))
+			panel->backlight.hz_to_pwm = lpt_hz_to_pwm;
+		else
+			panel->backlight.hz_to_pwm = spt_hz_to_pwm;
+	} else if (HAS_PCH_SPLIT(dev_priv)) {
+		panel->backlight.setup = pch_setup_backlight;
+		panel->backlight.enable = pch_enable_backlight;
+		panel->backlight.disable = pch_disable_backlight;
+		panel->backlight.set = pch_set_backlight;
+		panel->backlight.get = pch_get_backlight;
+		panel->backlight.hz_to_pwm = pch_hz_to_pwm;
+	} else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
+		if (connector->base.connector_type == DRM_MODE_CONNECTOR_DSI) {
+			panel->backlight.setup = pwm_setup_backlight;
+			panel->backlight.enable = pwm_enable_backlight;
+			panel->backlight.disable = pwm_disable_backlight;
+			panel->backlight.set = pwm_set_backlight;
+			panel->backlight.get = pwm_get_backlight;
+		} else {
+			panel->backlight.setup = vlv_setup_backlight;
+			panel->backlight.enable = vlv_enable_backlight;
+			panel->backlight.disable = vlv_disable_backlight;
+			panel->backlight.set = vlv_set_backlight;
+			panel->backlight.get = vlv_get_backlight;
+			panel->backlight.hz_to_pwm = vlv_hz_to_pwm;
+		}
+	} else if (IS_GEN(dev_priv, 4)) {
+		panel->backlight.setup = i965_setup_backlight;
+		panel->backlight.enable = i965_enable_backlight;
+		panel->backlight.disable = i965_disable_backlight;
+		panel->backlight.set = i9xx_set_backlight;
+		panel->backlight.get = i9xx_get_backlight;
+		panel->backlight.hz_to_pwm = i965_hz_to_pwm;
+	} else {
+		panel->backlight.setup = i9xx_setup_backlight;
+		panel->backlight.enable = i9xx_enable_backlight;
+		panel->backlight.disable = i9xx_disable_backlight;
+		panel->backlight.set = i9xx_set_backlight;
+		panel->backlight.get = i9xx_get_backlight;
+		panel->backlight.hz_to_pwm = i9xx_hz_to_pwm;
+	}
+}
+
+int intel_panel_init(struct intel_panel *panel,
+		     struct drm_display_mode *fixed_mode,
+		     struct drm_display_mode *downclock_mode)
+{
+	intel_panel_init_backlight_funcs(panel);
+
+	panel->fixed_mode = fixed_mode;
+	panel->downclock_mode = downclock_mode;
+
+	return 0;
+}
+
+void intel_panel_fini(struct intel_panel *panel)
+{
+	struct intel_connector *intel_connector =
+		container_of(panel, struct intel_connector, panel);
+
+	intel_panel_destroy_backlight(panel);
+
+	if (panel->fixed_mode)
+		drm_mode_destroy(intel_connector->base.dev, panel->fixed_mode);
+
+	if (panel->downclock_mode)
+		drm_mode_destroy(intel_connector->base.dev,
+				panel->downclock_mode);
+}