[PATCH v2 4/5] drm: bridge: lvds-encoder: allow specifying the input bus format

[Peter Rosin]

If the bridge changes the bus format, allow this to be described in
the bridge, instead of providing false information about the bus
format of the connector or panel.

Signed-off-by: Peter Rosin <peda at axentia.se>
---
 .../bindings/display/bridge/lvds-transmitter.txt   |  6 ++++++
 drivers/gpu/drm/bridge/lvds-encoder.c              | 25 ++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt b/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt
index 50220190c203..8d40a2069252 100644
--- a/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt
+++ b/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt
@@ -30,6 +30,12 @@ Required properties:
   device-specific version corresponding to the device first
   followed by the generic version.
 
+Optional properties:
+
+- interface-pix-fmt:
+  List of valid input bus formats of the encoder. Recognized bus formats
+  are listed in ../bus-format.txt
+
 Required nodes:
 
 This device has two video ports. Their connections are modeled using the OF
diff --git a/drivers/gpu/drm/bridge/lvds-encoder.c b/drivers/gpu/drm/bridge/lvds-encoder.c
index 75b0d3f6e4de..b78619b5560a 100644
--- a/drivers/gpu/drm/bridge/lvds-encoder.c
+++ b/drivers/gpu/drm/bridge/lvds-encoder.c
@@ -9,6 +9,7 @@
 
 #include <drm/drmP.h>
 #include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 
 #include <linux/of_graph.h>
@@ -16,6 +17,8 @@
 struct lvds_encoder {
 	struct drm_bridge bridge;
 	struct drm_bridge *panel_bridge;
+	int num_bus_formats;
+	u32 *bus_formats;
 };
 
 static int lvds_encoder_attach(struct drm_bridge *bridge)
@@ -28,8 +31,22 @@ static int lvds_encoder_attach(struct drm_bridge *bridge)
 				 bridge);
 }
 
+static int lvds_encoder_input_formats(struct drm_bridge *bridge,
+				      const u32 **bus_formats)
+{
+	struct lvds_encoder *lvds_encoder = container_of(bridge,
+							 struct lvds_encoder,
+							 bridge);
+
+	if (lvds_encoder->num_bus_formats)
+		*bus_formats = lvds_encoder->bus_formats;
+
+	return lvds_encoder->num_bus_formats;
+}
+
 static struct drm_bridge_funcs funcs = {
 	.attach = lvds_encoder_attach,
+	.input_formats = lvds_encoder_input_formats,
 };
 
 static int lvds_encoder_probe(struct platform_device *pdev)
@@ -39,6 +56,7 @@ static int lvds_encoder_probe(struct platform_device *pdev)
 	struct device_node *panel_node;
 	struct drm_panel *panel;
 	struct lvds_encoder *lvds_encoder;
+	int ret;
 
 	lvds_encoder = devm_kzalloc(&pdev->dev, sizeof(*lvds_encoder),
 				    GFP_KERNEL);
@@ -79,6 +97,12 @@ static int lvds_encoder_probe(struct platform_device *pdev)
 	if (IS_ERR(lvds_encoder->panel_bridge))
 		return PTR_ERR(lvds_encoder->panel_bridge);
 
+	ret = drm_of_bus_formats(pdev->dev.of_node, "interface-pix-fmt",
+				 &lvds_encoder->bus_formats);
+	if (ret < 0)
+		return ret;
+	lvds_encoder->num_bus_formats = ret;
+
 	/* The panel_bridge bridge is attached to the panel's of_node,
 	 * but we need a bridge attached to our of_node for our user
 	 * to look up.
@@ -96,6 +120,7 @@ static int lvds_encoder_remove(struct platform_device *pdev)
 {
 	struct lvds_encoder *lvds_encoder = platform_get_drvdata(pdev);
 
+	kfree(lvds_encoder->bus_formats);
 	drm_bridge_remove(&lvds_encoder->bridge);
 
 	return 0;
-- 
2.11.0