drm/mcde: Support DPI output

This implements support for DPI output using the port node
in the device tree to connect a DPI LCD display to the
MCDE. The block also supports TV-out but we leave that
for another day when we have a hardware using it.

We implement parsing and handling of the "port" node,
and follow that to the DPI endpoint.

The clock divider used by the MCDE to divide down the
"lcdclk" (this has been designed for TV-like frequencies)
is represented by an ordinary clock provider internally
in the MCDE. This idea was inspired by the PL111 solution
by Eric Anholt: the divider also works very similar to
the Pl111 clock divider.

We take care to clear up some errors regarding the number
of available formatters and their type. We have 6 DSI
formatters and 2 DPI formatters.

Tested on the Samsung GT-I9070 Janice mobile phone.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Stephan Gerhold <stephan@gerhold.net>
Cc: phone-devel@vger.kernel.org
Cc: upstreaming@lists.sr.ht
Link: https://patchwork.freedesktop.org/patch/msgid/20201112142925.2571179-2-linus.walleij@linaro.org

1 files changed, 270 insertions, 34 deletions

diff --git a/drivers/gpu/drm/mcde/mcde_display.c b/drivers/gpu/drm/mcde/mcde_display.c
index f461c594993c..192e11c88d72 100644
--- a/drivers/gpu/drm/mcde/mcde_display.c
+++ b/drivers/gpu/drm/mcde/mcde_display.c
@@ -8,6 +8,7 @@
 #include <linux/delay.h>
 #include <linux/dma-buf.h>
 #include <linux/regulator/consumer.h>
+#include <linux/media-bus-format.h>
 
 #include <drm/drm_device.h>
 #include <drm/drm_fb_cma_helper.h>
@@ -16,6 +17,7 @@
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_mipi_dsi.h>
 #include <drm/drm_simple_kms_helper.h>
+#include <drm/drm_bridge.h>
 #include <drm/drm_vblank.h>
 #include <video/mipi_display.h>
 
@@ -57,10 +59,15 @@ enum mcde_overlay {
 	MCDE_OVERLAY_5,
 };
 
-enum mcde_dsi_formatter {
+enum mcde_formatter {
 	MCDE_DSI_FORMATTER_0 = 0,
 	MCDE_DSI_FORMATTER_1,
 	MCDE_DSI_FORMATTER_2,
+	MCDE_DSI_FORMATTER_3,
+	MCDE_DSI_FORMATTER_4,
+	MCDE_DSI_FORMATTER_5,
+	MCDE_DPI_FORMATTER_0,
+	MCDE_DPI_FORMATTER_1,
 };
 
 void mcde_display_irq(struct mcde *mcde)
@@ -81,7 +88,7 @@ void mcde_display_irq(struct mcde *mcde)
 	 *
 	 * TODO: Currently only one DSI link is supported.
 	 */
-	if (mcde_dsi_irq(mcde->mdsi)) {
+	if (!mcde->dpi_output && mcde_dsi_irq(mcde->mdsi)) {
 		u32 val;
 
 		/*
@@ -553,6 +560,7 @@ static void mcde_configure_channel(struct mcde *mcde, enum mcde_channel ch,
 			<< MCDE_CHNLXSYNCHMOD_OUT_SYNCH_SRC_SHIFT;
 		break;
 	case MCDE_VIDEO_FORMATTER_FLOW:
+	case MCDE_DPI_FORMATTER_FLOW:
 		val = MCDE_CHNLXSYNCHMOD_SRC_SYNCH_HARDWARE
 			<< MCDE_CHNLXSYNCHMOD_SRC_SYNCH_SHIFT;
 		val |= MCDE_CHNLXSYNCHMOD_OUT_SYNCH_SRC_FORMATTER
@@ -591,10 +599,35 @@ static void mcde_configure_channel(struct mcde *mcde, enum mcde_channel ch,
 		       mcde->regs + mux);
 		break;
 	}
+
+	/*
+	 * If using DPI configure the sync event.
+	 * TODO: this is for LCD only, it does not cover TV out.
+	 */
+	if (mcde->dpi_output) {
+		u32 stripwidth;
+
+		stripwidth = 0xF000 / (mode->vdisplay * 4);
+		dev_info(mcde->dev, "stripwidth: %d\n", stripwidth);
+
+		val = MCDE_SYNCHCONF_HWREQVEVENT_ACTIVE_VIDEO |
+			(mode->hdisplay - 1 - stripwidth) << MCDE_SYNCHCONF_HWREQVCNT_SHIFT |
+			MCDE_SYNCHCONF_SWINTVEVENT_ACTIVE_VIDEO |
+			(mode->hdisplay - 1 - stripwidth) << MCDE_SYNCHCONF_SWINTVCNT_SHIFT;
+
+		switch (fifo) {
+		case MCDE_FIFO_A:
+			writel(val, mcde->regs + MCDE_SYNCHCONFA);
+			break;
+		case MCDE_FIFO_B:
+			writel(val, mcde->regs + MCDE_SYNCHCONFB);
+			break;
+		}
+	}
 }
 
 static void mcde_configure_fifo(struct mcde *mcde, enum mcde_fifo fifo,
-				enum mcde_dsi_formatter fmt,
+				enum mcde_formatter fmt,
 				int fifo_wtrmrk)
 {
 	u32 val;
@@ -615,12 +648,49 @@ static void mcde_configure_fifo(struct mcde *mcde, enum mcde_fifo fifo,
 	}
 
 	val = fifo_wtrmrk << MCDE_CTRLX_FIFOWTRMRK_SHIFT;
-	/* We only support DSI formatting for now */
-	val |= MCDE_CTRLX_FORMTYPE_DSI <<
-		MCDE_CTRLX_FORMTYPE_SHIFT;
 
-	/* Select the formatter to use for this FIFO */
-	val |= fmt << MCDE_CTRLX_FORMID_SHIFT;
+	/*
+	 * Select the formatter to use for this FIFO
+	 *
+	 * The register definitions imply that different IDs should be used
+	 * by the DSI formatters depending on if they are in VID or CMD
+	 * mode, and the manual says they are dedicated but identical.
+	 * The vendor code uses them as it seems fit.
+	 */
+	switch (fmt) {
+	case MCDE_DSI_FORMATTER_0:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI0VID << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_1:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI0CMD << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_2:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI1VID << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_3:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI1CMD << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_4:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI2VID << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_5:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI2CMD << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DPI_FORMATTER_0:
+		val |= MCDE_CTRLX_FORMTYPE_DPITV << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DPIA << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DPI_FORMATTER_1:
+		val |= MCDE_CTRLX_FORMTYPE_DPITV << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DPIB << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	}
 	writel(val, mcde->regs + ctrl);
 
 	/* Blend source with Alpha 0xff on FIFO */
@@ -628,17 +698,54 @@ static void mcde_configure_fifo(struct mcde *mcde, enum mcde_fifo fifo,
 		0xff << MCDE_CRX0_ALPHABLEND_SHIFT;
 	writel(val, mcde->regs + cr0);
 
-	/* Set-up from mcde_fmtr_dsi.c, fmtr_dsi_enable_video() */
-
-	/* Use the MCDE clock for this FIFO */
-	val = MCDE_CRX1_CLKSEL_MCDECLK << MCDE_CRX1_CLKSEL_SHIFT;
+	spin_lock(&mcde->fifo_crx1_lock);
+	val = readl(mcde->regs + cr1);
+	/*
+	 * Set-up from mcde_fmtr_dsi.c, fmtr_dsi_enable_video()
+	 * FIXME: a different clock needs to be selected for TV out.
+	 */
+	if (mcde->dpi_output) {
+		struct drm_connector *connector = drm_panel_bridge_connector(mcde->bridge);
+		u32 bus_format;
+
+		/* Assume RGB888 24 bit if we have no further info */
+		if (!connector->display_info.num_bus_formats) {
+			dev_info(mcde->dev, "panel does not specify bus format, assume RGB888\n");
+			bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+		} else {
+			bus_format = connector->display_info.bus_formats[0];
+		}
 
-	/* TODO: when adding DPI support add OUTBPP etc here */
+		/*
+		 * Set up the CDWIN and OUTBPP for the LCD
+		 *
+		 * FIXME: fill this in if you know the correspondance between the MIPI
+		 * DPI specification and the media bus formats.
+		 */
+		val &= ~MCDE_CRX1_CDWIN_MASK;
+		val &= ~MCDE_CRX1_OUTBPP_MASK;
+		switch (bus_format) {
+		case MEDIA_BUS_FMT_RGB888_1X24:
+			val |= MCDE_CRX1_CDWIN_24BPP << MCDE_CRX1_CDWIN_SHIFT;
+			val |= MCDE_CRX1_OUTBPP_24BPP << MCDE_CRX1_OUTBPP_SHIFT;
+			break;
+		default:
+			dev_err(mcde->dev, "unknown bus format, assume RGB888\n");
+			val |= MCDE_CRX1_CDWIN_24BPP << MCDE_CRX1_CDWIN_SHIFT;
+			val |= MCDE_CRX1_OUTBPP_24BPP << MCDE_CRX1_OUTBPP_SHIFT;
+			break;
+		}
+	} else {
+		/* Use the MCDE clock for DSI */
+		val &= ~MCDE_CRX1_CLKSEL_MASK;
+		val = MCDE_CRX1_CLKSEL_MCDECLK << MCDE_CRX1_CLKSEL_SHIFT;
+	}
 	writel(val, mcde->regs + cr1);
+	spin_unlock(&mcde->fifo_crx1_lock);
 };
 
 static void mcde_configure_dsi_formatter(struct mcde *mcde,
-					 enum mcde_dsi_formatter fmt,
+					 enum mcde_formatter fmt,
 					 u32 formatter_frame,
 					 int pkt_size)
 {
@@ -678,6 +785,9 @@ static void mcde_configure_dsi_formatter(struct mcde *mcde,
 		delay0 = MCDE_DSIVID2DELAY0;
 		delay1 = MCDE_DSIVID2DELAY1;
 		break;
+	default:
+		dev_err(mcde->dev, "tried to configure a non-DSI formatter as DSI\n");
+		return;
 	}
 
 	/*
@@ -859,6 +969,103 @@ static int mcde_dsi_get_pkt_div(int ppl, int fifo_size)
 	return 1;
 }
 
+static void mcde_setup_dpi(struct mcde *mcde, const struct drm_display_mode *mode,
+			   int *fifo_wtrmrk_lvl)
+{
+	struct drm_connector *connector = drm_panel_bridge_connector(mcde->bridge);
+	u32 hsw, hfp, hbp;
+	u32 vsw, vfp, vbp;
+	u32 val;
+
+	/* FIXME: we only support LCD, implement TV out */
+	hsw = mode->hsync_end - mode->hsync_start;
+	hfp = mode->hsync_start - mode->hdisplay;
+	hbp = mode->htotal - mode->hsync_end;
+	vsw = mode->vsync_end - mode->vsync_start;
+	vfp = mode->vsync_start - mode->vdisplay;
+	vbp = mode->vtotal - mode->vsync_end;
+
+	dev_info(mcde->dev, "output on DPI LCD from channel A\n");
+	/* Display actual values */
+	dev_info(mcde->dev, "HSW: %d, HFP: %d, HBP: %d, VSW: %d, VFP: %d, VBP: %d\n",
+		 hsw, hfp, hbp, vsw, vfp, vbp);
+
+	/*
+	 * The pixel fetcher is 128 64-bit words deep = 1024 bytes.
+	 * One overlay of 32bpp (4 cpp) assumed, fetch 160 pixels.
+	 * 160 * 4 = 640 bytes.
+	 */
+	*fifo_wtrmrk_lvl = 640;
+
+	/* Set up the main control, watermark level at 7 */
+	val = 7 << MCDE_CONF0_IFIFOCTRLWTRMRKLVL_SHIFT;
+
+	/*
+	 * This sets up the internal silicon muxing of the DPI
+	 * lines. This is how the silicon connects out to the
+	 * external pins, then the pins need to be further
+	 * configured into "alternate functions" using pin control
+	 * to actually get the signals out.
+	 *
+	 * FIXME: this is hardcoded to the only setting found in
+	 * the wild. If we need to use different settings for
+	 * different DPI displays, make this parameterizable from
+	 * the device tree.
+	 */
+	/* 24 bits DPI: connect Ch A LSB to D[0:7] */
+	val |= 0 << MCDE_CONF0_OUTMUX0_SHIFT;
+	/* 24 bits DPI: connect Ch A MID to D[8:15] */
+	val |= 1 << MCDE_CONF0_OUTMUX1_SHIFT;
+	/* Don't care about this muxing */
+	val |= 0 << MCDE_CONF0_OUTMUX2_SHIFT;
+	/* Don't care about this muxing */
+	val |= 0 << MCDE_CONF0_OUTMUX3_SHIFT;
+	/* 24 bits DPI: connect Ch A MSB to D[32:39] */
+	val |= 2 << MCDE_CONF0_OUTMUX4_SHIFT;
+	/* Syncmux bits zero: DPI channel A */
+	writel(val, mcde->regs + MCDE_CONF0);
+
+	/* This hammers us into LCD mode */
+	writel(0, mcde->regs + MCDE_TVCRA);
+
+	/* Front porch and sync width */
+	val = (vsw << MCDE_TVBL1_BEL1_SHIFT);
+	val |= (vfp << MCDE_TVBL1_BSL1_SHIFT);
+	writel(val, mcde->regs + MCDE_TVBL1A);
+	/* The vendor driver sets the same value into TVBL2A */
+	writel(val, mcde->regs + MCDE_TVBL2A);
+
+	/* Vertical back porch */
+	val = (vbp << MCDE_TVDVO_DVO1_SHIFT);
+	/* The vendor drivers sets the same value into TVDVOA */
+	val |= (vbp << MCDE_TVDVO_DVO2_SHIFT);
+	writel(val, mcde->regs + MCDE_TVDVOA);
+
+	/* Horizontal back porch, as 0 = 1 cycle we need to subtract 1 */
+	writel((hbp - 1), mcde->regs + MCDE_TVTIM1A);
+
+	/* Horizongal sync width and horizonal front porch, 0 = 1 cycle */
+	val = ((hsw - 1) << MCDE_TVLBALW_LBW_SHIFT);
+	val |= ((hfp - 1) << MCDE_TVLBALW_ALW_SHIFT);
+	writel(val, mcde->regs + MCDE_TVLBALWA);
+
+	/* Blank some TV registers we don't use */
+	writel(0, mcde->regs + MCDE_TVISLA);
+	writel(0, mcde->regs + MCDE_TVBLUA);
+
+	/* Set up sync inversion etc */
+	val = 0;
+	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+		val |= MCDE_LCDTIM1B_IHS;
+	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+		val |= MCDE_LCDTIM1B_IVS;
+	if (connector->display_info.bus_flags & DRM_BUS_FLAG_DE_LOW)
+		val |= MCDE_LCDTIM1B_IOE;
+	if (connector->display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
+		val |= MCDE_LCDTIM1B_IPC;
+	writel(val, mcde->regs + MCDE_LCDTIM1A);
+}
+
 static void mcde_setup_dsi(struct mcde *mcde, const struct drm_display_mode *mode,
 			   int cpp, int *fifo_wtrmrk_lvl, int *dsi_formatter_frame,
 			   int *dsi_pkt_size)
@@ -976,8 +1183,11 @@ static void mcde_display_enable(struct drm_simple_display_pipe *pipe,
 	writel(0, mcde->regs + MCDE_IMSCERR);
 	writel(0xFFFFFFFF, mcde->regs + MCDE_RISERR);
 
-	mcde_setup_dsi(mcde, mode, cpp, &fifo_wtrmrk,
-		       &dsi_formatter_frame, &dsi_pkt_size);
+	if (mcde->dpi_output)
+		mcde_setup_dpi(mcde, mode, &fifo_wtrmrk);
+	else
+		mcde_setup_dsi(mcde, mode, cpp, &fifo_wtrmrk,
+			       &dsi_formatter_frame, &dsi_pkt_size);
 
 	mcde->stride = mode->hdisplay * cpp;
 	dev_dbg(drm->dev, "Overlay line stride: %u bytes\n",
@@ -1009,29 +1219,47 @@ static void mcde_display_enable(struct drm_simple_display_pipe *pipe,
 	 */
 	mcde_configure_channel(mcde, MCDE_CHANNEL_0, MCDE_FIFO_A, mode);
 
-	/* Configure FIFO A to use DSI formatter 0 */
-	mcde_configure_fifo(mcde, MCDE_FIFO_A, MCDE_DSI_FORMATTER_0,
-			    fifo_wtrmrk);
+	if (mcde->dpi_output) {
+		unsigned long lcd_freq;
+
+		/* Configure FIFO A to use DPI formatter 0 */
+		mcde_configure_fifo(mcde, MCDE_FIFO_A, MCDE_DPI_FORMATTER_0,
+				    fifo_wtrmrk);
+
+		/* Set up and enable the LCD clock */
+		lcd_freq = clk_round_rate(mcde->fifoa_clk, mode->clock * 1000);
+		ret = clk_set_rate(mcde->fifoa_clk, lcd_freq);
+		if (ret)
+			dev_err(mcde->dev, "failed to set LCD clock rate %lu Hz\n",
+				lcd_freq);
+		ret = clk_prepare_enable(mcde->fifoa_clk);
+		if (ret) {
+			dev_err(mcde->dev, "failed to enable FIFO A DPI clock\n");
+			return;
+		}
+		dev_info(mcde->dev, "LCD FIFO A clk rate %lu Hz\n",
+			 clk_get_rate(mcde->fifoa_clk));
+	} else {
+		/* Configure FIFO A to use DSI formatter 0 */
+		mcde_configure_fifo(mcde, MCDE_FIFO_A, MCDE_DSI_FORMATTER_0,
+				    fifo_wtrmrk);
 
-	/*
-	 * This brings up the DSI bridge which is tightly connected
-	 * to the MCDE DSI formatter.
-	 *
-	 * FIXME: if we want to use another formatter, such as DPI,
-	 * we need to be more elaborate here and select the appropriate
-	 * bridge.
-	 */
-	mcde_dsi_enable(mcde->bridge);
+		/*
+		 * This brings up the DSI bridge which is tightly connected
+		 * to the MCDE DSI formatter.
+		 */
+		mcde_dsi_enable(mcde->bridge);
 
-	/* Configure the DSI formatter 0 for the DSI panel output */
-	mcde_configure_dsi_formatter(mcde, MCDE_DSI_FORMATTER_0,
-				     dsi_formatter_frame, dsi_pkt_size);
+		/* Configure the DSI formatter 0 for the DSI panel output */
+		mcde_configure_dsi_formatter(mcde, MCDE_DSI_FORMATTER_0,
+					     dsi_formatter_frame, dsi_pkt_size);
+	}
 
 	switch (mcde->flow_mode) {
 	case MCDE_COMMAND_TE_FLOW:
 	case MCDE_COMMAND_BTA_TE_FLOW:
 	case MCDE_VIDEO_TE_FLOW:
-		/* We are using TE in some comination */
+		/* We are using TE in some combination */
 		if (mode->flags & DRM_MODE_FLAG_NVSYNC)
 			val = MCDE_VSCRC_VSPOL;
 		else
@@ -1083,8 +1311,12 @@ static void mcde_display_disable(struct drm_simple_display_pipe *pipe)
 	/* Disable FIFO A flow */
 	mcde_disable_fifo(mcde, MCDE_FIFO_A, true);
 
-	/* This disables the DSI bridge */
-	mcde_dsi_disable(mcde->bridge);
+	if (mcde->dpi_output) {
+		clk_disable_unprepare(mcde->fifoa_clk);
+	} else {
+		/* This disables the DSI bridge */
+		mcde_dsi_disable(mcde->bridge);
+	}
 
 	event = crtc->state->event;
 	if (event) {
@@ -1275,6 +1507,10 @@ int mcde_display_init(struct drm_device *drm)
 		DRM_FORMAT_YUV422,
 	};
 
+	ret = mcde_init_clock_divider(mcde);
+	if (ret)
+		return ret;
+
 	ret = drm_simple_display_pipe_init(drm, &mcde->pipe,
 					   &mcde_display_funcs,
 					   formats, ARRAY_SIZE(formats),