drm: introduce pipe color correction properties

Patch based on a previous series by Shashank Sharma.

This introduces optional properties to enable color correction at the
pipe level. It relies on 3 transformations applied to every pixels
displayed. First a lookup into a degamma table, then a multiplication
of the rgb components by a 3x3 matrix and finally another lookup into
a gamma table.

The following properties can be added to a pipe :
  - DEGAMMA_LUT : blob containing degamma LUT
  - DEGAMMA_LUT_SIZE : number of elements in DEGAMMA_LUT
  - CTM : transformation matrix applied after the degamma LUT
  - GAMMA_LUT : blob containing gamma LUT
  - GAMMA_LUT_SIZE : number of elements in GAMMA_LUT

DEGAMMA_LUT_SIZE and GAMMA_LUT_SIZE are read only properties, set by
the driver to tell userspace applications what sizes should be the
lookup tables in DEGAMMA_LUT and GAMMA_LUT.

A helper is also provided so legacy gamma correction is redirected
through these new properties.

v2: Register LUT size properties as range

v3: Fix round in drm_color_lut_get_value() helper
    More docs on how degamma/gamma properties are used

v4: Update contributors

v5: Rename CTM_MATRIX property to CTM (Doh!)
    Add legacy gamma_set atomic helper
    Describe CTM/LUT acronyms in the kernel doc

v6: Fix missing blob unref in drm_atomic_helper_crtc_reset

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Kumar, Kiran S <kiran.s.kumar@intel.com>
Signed-off-by: Kausal Malladi <kausalmalladi@gmail.com>
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Acked-by: Rob Bradford <robert.bradford@intel.com>
[danvet: CrOS maintainers are also happy with the userspacde side:
https://codereview.chromium.org/1182063002/ ]
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1456506302-640-4-git-send-email-lionel.g.landwerlin@intel.com

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 7539eea4ccbc..79555d2b1b87 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -1075,3 +1075,36 @@ int drm_helper_crtc_mode_set_base(struct drm_crtc *crtc, int x, int y,
 	return drm_plane_helper_commit(plane, plane_state, old_fb);
 }
 EXPORT_SYMBOL(drm_helper_crtc_mode_set_base);
+
+/**
+ * drm_helper_crtc_enable_color_mgmt - enable color management properties
+ * @crtc: DRM CRTC
+ * @degamma_lut_size: the size of the degamma lut (before CSC)
+ * @gamma_lut_size: the size of the gamma lut (after CSC)
+ *
+ * This function lets the driver enable the color correction properties on a
+ * CRTC. This includes 3 degamma, csc and gamma properties that userspace can
+ * set and 2 size properties to inform the userspace of the lut sizes.
+ */
+void drm_helper_crtc_enable_color_mgmt(struct drm_crtc *crtc,
+				       int degamma_lut_size,
+				       int gamma_lut_size)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_mode_config *config = &dev->mode_config;
+
+	drm_object_attach_property(&crtc->base,
+				   config->degamma_lut_property, 0);
+	drm_object_attach_property(&crtc->base,
+				   config->ctm_property, 0);
+	drm_object_attach_property(&crtc->base,
+				   config->gamma_lut_property, 0);
+
+	drm_object_attach_property(&crtc->base,
+				   config->degamma_lut_size_property,
+				   degamma_lut_size);
+	drm_object_attach_property(&crtc->base,
+				   config->gamma_lut_size_property,
+				   gamma_lut_size);
+}
+EXPORT_SYMBOL(drm_helper_crtc_enable_color_mgmt);