[v3 1/7] drm: Add gamma mode property

[Uma Shankar <uma.shankar@intel.com>]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Add a gamma mode property to enable various kind of
gamma modes supported by platforms like: Interpolated, Split,
Multi Segmented etc. Userspace can get this property and
should be able to get the platform capabilties wrt various
gamma modes possible and the possible ranges.

It can select one of the modes exposed as blob_id as an
enum and set the respective mode.

It can then create the LUT and send it to driver using
already available GAMMA_LUT property as blob.

v2: Addressed Sam Ravnborg's review comments. Implemented
gamma mode with just one property and renamed the current
one to GAMMA_MODE property as recommended by Ville.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
---
 drivers/gpu/drm/drm_atomic_uapi.c |  5 +++
 drivers/gpu/drm/drm_color_mgmt.c  | 77 +++++++++++++++++++++++++++++++++++++++
 include/drm/drm_color_mgmt.h      |  8 ++++
 include/drm/drm_crtc.h            |  7 ++++
 include/drm/drm_mode_config.h     |  6 +++
 include/uapi/drm/drm_mode.h       | 38 +++++++++++++++++++
 6 files changed, 141 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index ea797d4..d85e0c9 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -459,6 +459,9 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 					&replaced);
 		state->color_mgmt_changed |= replaced;
 		return ret;
+	} else if (property == config->gamma_mode_property) {
+		state->gamma_mode = val;
+		state->color_mgmt_changed |= replaced;
 	} else if (property == config->prop_out_fence_ptr) {
 		s32 __user *fence_ptr = u64_to_user_ptr(val);
 
@@ -495,6 +498,8 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 		*val = (state->mode_blob) ? state->mode_blob->base.id : 0;
 	else if (property == config->prop_vrr_enabled)
 		*val = state->vrr_enabled;
+	else if (property == config->gamma_mode_property)
+		*val = state->gamma_mode;
 	else if (property == config->degamma_lut_property)
 		*val = (state->degamma_lut) ? state->degamma_lut->base.id : 0;
 	else if (property == config->ctm_property)
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index d5d34d0..4d6792d 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -176,6 +176,83 @@ void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
 }
 EXPORT_SYMBOL(drm_crtc_enable_color_mgmt);
 
+void drm_crtc_attach_gamma_mode_property(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_mode_config *config = &dev->mode_config;
+
+	if (!config->gamma_mode_property)
+		return;
+
+	drm_object_attach_property(&crtc->base,
+				   config->gamma_mode_property, 0);
+}
+EXPORT_SYMBOL(drm_crtc_attach_gamma_mode_property);
+
+int drm_color_create_gamma_mode_property(struct drm_device *dev,
+					 int num_values)
+{
+	struct drm_mode_config *config = &dev->mode_config;
+	struct drm_property *prop;
+
+	prop = drm_property_create(dev,
+				   DRM_MODE_PROP_ENUM,
+				   "GAMMA_MODE", num_values);
+	if (!prop)
+		return -ENOMEM;
+
+	config->gamma_mode_property = prop;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_color_create_gamma_mode_property);
+
+int drm_color_add_gamma_mode_range(struct drm_device *dev,
+				   const char *name,
+				   const struct drm_color_lut_range *ranges,
+				   size_t length)
+{
+	struct drm_mode_config *config = &dev->mode_config;
+	struct drm_property_blob *blob;
+	struct drm_property *prop;
+	int num_ranges = length / sizeof(ranges[0]);
+	int i, ret, num_types_0;
+
+	if (WARN_ON(length == 0 || length % sizeof(ranges[0]) != 0))
+		return -EINVAL;
+
+	num_types_0 = hweight8(ranges[0].flags & (DRM_MODE_LUT_GAMMA |
+						  DRM_MODE_LUT_DEGAMMA));
+	if (num_types_0 == 0)
+		return -EINVAL;
+
+	for (i = 1; i < num_ranges; i++) {
+		int num_types = hweight8(ranges[i].flags & (DRM_MODE_LUT_GAMMA |
+							    DRM_MODE_LUT_DEGAMMA));
+
+		/* either all ranges have DEGAMMA|GAMMA or none have it */
+		if (num_types_0 != num_types)
+			return -EINVAL;
+	}
+
+	prop = config->gamma_mode_property;
+	if (!prop)
+		return -EINVAL;
+
+	blob = drm_property_create_blob(dev, length, ranges);
+	if (IS_ERR(blob))
+		return PTR_ERR(blob);
+
+	ret = drm_property_add_enum(prop, blob->base.id, name);
+	if (ret) {
+		drm_property_blob_put(blob);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_color_add_gamma_mode_range);
+
 /**
  * drm_mode_crtc_set_gamma_size - set the gamma table size
  * @crtc: CRTC to set the gamma table size for
diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
index d1c662d..f18e9b8 100644
--- a/include/drm/drm_color_mgmt.h
+++ b/include/drm/drm_color_mgmt.h
@@ -51,6 +51,14 @@ static inline int drm_color_lut_size(const struct drm_property_blob *blob)
 	return blob->length / sizeof(struct drm_color_lut);
 }
 
+int drm_color_create_gamma_mode_property(struct drm_device *dev,
+					 int num_values);
+void drm_crtc_attach_gamma_mode_property(struct drm_crtc *crtc);
+int drm_color_add_gamma_mode_range(struct drm_device *dev,
+				   const char *name,
+				   const struct drm_color_lut_range *ranges,
+				   size_t length);
+
 enum drm_color_encoding {
 	DRM_COLOR_YCBCR_BT601,
 	DRM_COLOR_YCBCR_BT709,
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 58ad983..f2e60bd 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -249,6 +249,13 @@ struct drm_crtc_state {
 	struct drm_property_blob *mode_blob;
 
 	/**
+	 * @gamma_mode: This is a blob_id and exposes the platform capabilties
+	 * wrt to various gamma modes and the respective lut ranges. This also
+	 * helps user select a gamma mode amongst the supported ones.
+	 */
+	u32 gamma_mode;
+
+	/**
 	 * @degamma_lut:
 	 *
 	 * Lookup table for converting framebuffer pixel data before apply the
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 7f60e8e..8f961c5b 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -761,6 +761,12 @@ struct drm_mode_config {
 	 */
 	struct drm_property *content_type_property;
 	/**
+	 * @gamma_mode_property: Optional CRTC property to enumerate and
+	 * select the mode of the crtc gamma/degmama LUTs. This also exposes
+	 * the lut ranges of the various supported gamma modes to userspace.
+	 */
+	struct drm_property *gamma_mode_property;
+	/**
 	 * @degamma_lut_property: Optional CRTC property to set the LUT used to
 	 * convert the framebuffer's colors to linear gamma.
 	 */
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 83cd163..e70b7f8 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -630,6 +630,44 @@ struct drm_color_lut {
 	__u16 reserved;
 };
 
+/*
+ * DRM_MODE_LUT_GAMMA|DRM_MODE_LUT_DEGAMMA is legal and means the LUT
+ * can be used for either purpose, but not simultaneously. To expose
+ * modes that support gamma and degamma simultaneously the gamma mode
+ * must declare distinct DRM_MODE_LUT_GAMMA and DRM_MODE_LUT_DEGAMMA
+ * ranges.
+ */
+/* LUT is for gamma (after CTM) */
+#define DRM_MODE_LUT_GAMMA BIT(0)
+/* LUT is for degamma (before CTM) */
+#define DRM_MODE_LUT_DEGAMMA BIT(1)
+/* linearly interpolate between the points */
+#define DRM_MODE_LUT_INTERPOLATE BIT(2)
+/*
+ * the last value of the previous range is the
+ * first value of the current range.
+ */
+#define DRM_MODE_LUT_REUSE_LAST BIT(3)
+/* the curve must be non-decreasing */
+#define DRM_MODE_LUT_NON_DECREASING BIT(4)
+/* the curve is reflected across origin for negative inputs */
+#define DRM_MODE_LUT_REFLECT_NEGATIVE BIT(5)
+/* the same curve (red) is used for blue and green channels as well */
+#define DRM_MODE_LUT_SINGLE_CHANNEL BIT(6)
+
+struct drm_color_lut_range {
+	/* DRM_MODE_LUT_* */
+	__u32 flags;
+	/* number of points on the curve */
+	__u16 count;
+	/* input/output bits per component */
+	__u8 input_bpc, output_bpc;
+	/* input start/end values */
+	__s32 start, end;
+	/* output min/max values */
+	__s32 min, max;
+};
+
 #define DRM_MODE_PAGE_FLIP_EVENT 0x01
 #define DRM_MODE_PAGE_FLIP_ASYNC 0x02
 #define DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE 0x4
-- 
1.9.1

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