[RFC PATCH 1/6] drm: Add support for extracting sync signal drive edge from videomode

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

From: Peter Ujfalusi <peter.ujfalusi@ti.com>

The sync in some panels needs to be driven by different edge of the pixel
clock compared to data. This is reflected by the
DISPLAY_FLAGS_SYNC_(POS|NEG)EDGE in videmode flags.
Add similar similar definitions for bus_flags and convert the sync drive
edge via drm_bus_flags_from_videomode().

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Jyri Sarha <jsarha@ti.com>
---
 drivers/gpu/drm/drm_modes.c | 15 +++++++++++----
 include/drm/drm_connector.h |  4 ++++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index e82b61e08f8c..1661bfc55687 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -659,10 +659,12 @@ EXPORT_SYMBOL_GPL(drm_display_mode_to_videomode);
  * drm_bus_flags_from_videomode - extract information about pixelclk and
  * DE polarity from videomode and store it in a separate variable
  * @vm: videomode structure to use
- * @bus_flags: information about pixelclk and DE polarity will be stored here
+ * @bus_flags: information about pixelclk, sync and DE polarity will be stored
+ * here
  *
- * Sets DRM_BUS_FLAG_DE_(LOW|HIGH) and DRM_BUS_FLAG_PIXDATA_(POS|NEG)EDGE
- * in @bus_flags according to DISPLAY_FLAGS found in @vm
+ * Sets DRM_BUS_FLAG_DE_(LOW|HIGH),  DRM_BUS_FLAG_PIXDATA_(POS|NEG)EDGE and
+ * DISPLAY_FLAGS_SYNC_(POS|NEG)EDGE in @bus_flags according to DISPLAY_FLAGS
+ * found in @vm
  */
 void drm_bus_flags_from_videomode(const struct videomode *vm, u32 *bus_flags)
 {
@@ -672,6 +674,11 @@ void drm_bus_flags_from_videomode(const struct videomode *vm, u32 *bus_flags)
 	if (vm->flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
 		*bus_flags |= DRM_BUS_FLAG_PIXDATA_NEGEDGE;
 
+	if (vm->flags & DISPLAY_FLAGS_SYNC_POSEDGE)
+		*bus_flags |= DRM_BUS_FLAG_SYNC_POSEDGE;
+	if (vm->flags & DISPLAY_FLAGS_SYNC_NEGEDGE)
+		*bus_flags |= DRM_BUS_FLAG_SYNC_NEGEDGE;
+
 	if (vm->flags & DISPLAY_FLAGS_DE_LOW)
 		*bus_flags |= DRM_BUS_FLAG_DE_LOW;
 	if (vm->flags & DISPLAY_FLAGS_DE_HIGH)
@@ -684,7 +691,7 @@ EXPORT_SYMBOL_GPL(drm_bus_flags_from_videomode);
  * of_get_drm_display_mode - get a drm_display_mode from devicetree
  * @np: device_node with the timing specification
  * @dmode: will be set to the return value
- * @bus_flags: information about pixelclk and DE polarity
+ * @bus_flags: information about pixelclk, sync and DE polarity
  * @index: index into the list of display timings in devicetree
  *
  * This function is expensive and should only be used, if only one mode is to be
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 675cc3f8cf85..8fa901637f00 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -290,6 +290,10 @@ struct drm_display_info {
 #define DRM_BUS_FLAG_DATA_MSB_TO_LSB	(1<<4)
 /* data is transmitted LSB to MSB on the bus */
 #define DRM_BUS_FLAG_DATA_LSB_TO_MSB	(1<<5)
+/* drive sync on pos. edge */
+#define DRM_BUS_FLAG_SYNC_POSEDGE	(1<<6)
+/* drive sync on neg. edge */
+#define DRM_BUS_FLAG_SYNC_NEGEDGE	(1<<7)
 
 	/**
 	 * @bus_flags: Additional information (like pixel signal polarity) for
-- 
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