[PATCH V2] drm/bridge: lvds-codec: Add support for pixel data sampling edge select

* [PATCH V2] drm/bridge: lvds-codec: Add support for pixel data sampling edge select
@ 2020-12-24  6:18 ` Marek Vasut
  0 siblings, 0 replies; 18+ messages in thread
From: Marek Vasut @ 2020-12-24  6:18 UTC (permalink / raw)
  To: dri-devel
  Cc: Marek Vasut, Benjamin Gaignard, Antonio Borneo, Vincent Abriou,
	Philippe Cornu, Yannick Fertre, Andrzej Hajda, Laurent Pinchart,
	Maxime Coquelin, Biju Das, Sam Ravnborg, linux-stm32,
	linux-arm-kernel, Alexandre Torgue

The OnSemi FIN3385 Parallel-to-LVDS encoder has a dedicated input line to
select input pixel data sampling edge. Add DT property "pixelclk-active",
same as the one used by display timings, and configure bus flags based on
this DT property.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Antonio Borneo <antonio.borneo@st.com>
Cc: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Philippe Cornu <philippe.cornu@st.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Vincent Abriou <vincent.abriou@st.com>
Cc: Yannick Fertre <yannick.fertre@st.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-stm32@st-md-mailman.stormreply.com
To: dri-devel@lists.freedesktop.org
---
V2: - Limit the pixelclk-active to encoders only
    - Update DT binding document
---
 .../bindings/display/bridge/lvds-codec.yaml   |  7 +++
 drivers/gpu/drm/bridge/lvds-codec.c           | 52 +++++++++++++------
 2 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml b/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml
index e5e3c72630cf..399a6528780a 100644
--- a/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml
@@ -74,6 +74,13 @@ properties:
 
     additionalProperties: false
 
+  pixelclk-active:
+    description: |
+      Data sampling on rising or falling edge.
+      Use 0 to sample pixel data on rising edge and
+      Use 1 to sample pixel data on falling edge and
+    enum: [0, 1]
+
   powerdown-gpios:
     description:
       The GPIO used to control the power down line of this device.
diff --git a/drivers/gpu/drm/bridge/lvds-codec.c b/drivers/gpu/drm/bridge/lvds-codec.c
index dcf579a4cf83..cab81ccd895d 100644
--- a/drivers/gpu/drm/bridge/lvds-codec.c
+++ b/drivers/gpu/drm/bridge/lvds-codec.c
@@ -15,13 +15,18 @@
 #include <drm/drm_bridge.h>
 #include <drm/drm_panel.h>
 
+struct lvds_codec_data {
+	u32 connector_type;
+	bool is_encoder;
+};
+
 struct lvds_codec {
 	struct device *dev;
 	struct drm_bridge bridge;
 	struct drm_bridge *panel_bridge;
+	struct drm_bridge_timings timings;
 	struct regulator *vcc;
 	struct gpio_desc *powerdown_gpio;
-	u32 connector_type;
 };
 
 static inline struct lvds_codec *to_lvds_codec(struct drm_bridge *bridge)
@@ -76,17 +81,20 @@ static const struct drm_bridge_funcs funcs = {
 
 static int lvds_codec_probe(struct platform_device *pdev)
 {
+	const struct lvds_codec_data *data;
 	struct device *dev = &pdev->dev;
 	struct device_node *panel_node;
 	struct drm_panel *panel;
 	struct lvds_codec *lvds_codec;
+	u32 val;
 
 	lvds_codec = devm_kzalloc(dev, sizeof(*lvds_codec), GFP_KERNEL);
 	if (!lvds_codec)
 		return -ENOMEM;
 
+	data = of_device_get_match_data(dev);
+
 	lvds_codec->dev = &pdev->dev;
-	lvds_codec->connector_type = (uintptr_t)of_device_get_match_data(dev);
 
 	lvds_codec->vcc = devm_regulator_get(lvds_codec->dev, "power");
 	if (IS_ERR(lvds_codec->vcc))
@@ -115,10 +123,22 @@ static int lvds_codec_probe(struct platform_device *pdev)
 
 	lvds_codec->panel_bridge =
 		devm_drm_panel_bridge_add_typed(dev, panel,
-						lvds_codec->connector_type);
+						data->connector_type);
 	if (IS_ERR(lvds_codec->panel_bridge))
 		return PTR_ERR(lvds_codec->panel_bridge);
 
+	/*
+	 * Encoder might sample data on different clock edge than the display,
+	 * for example OnSemi FIN3385 has a dedicated strapping pin to select
+	 * the sampling edge.
+	 */
+	if (data->is_encoder &&
+	    !of_property_read_u32(dev->of_node, "pixelclk-active", &val)) {
+		lvds_codec->timings.input_bus_flags = val ?
+			DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE :
+			DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE;
+	}
+
 	/*
 	 * 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
@@ -126,6 +146,7 @@ static int lvds_codec_probe(struct platform_device *pdev)
 	 */
 	lvds_codec->bridge.of_node = dev->of_node;
 	lvds_codec->bridge.funcs = &funcs;
+	lvds_codec->bridge.timings = &lvds_codec->timings;
 	drm_bridge_add(&lvds_codec->bridge);
 
 	platform_set_drvdata(pdev, lvds_codec);
@@ -142,19 +163,20 @@ static int lvds_codec_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct lvds_codec_data decoder_data = {
+	.connector_type = DRM_MODE_CONNECTOR_DPI,
+	.is_encoder = false,
+};
+
+static const struct lvds_codec_data encoder_data = {
+	.connector_type = DRM_MODE_CONNECTOR_LVDS,
+	.is_encoder = true,
+};
+
 static const struct of_device_id lvds_codec_match[] = {
-	{
-		.compatible = "lvds-decoder",
-		.data = (void *)DRM_MODE_CONNECTOR_DPI,
-	},
-	{
-		.compatible = "lvds-encoder",
-		.data = (void *)DRM_MODE_CONNECTOR_LVDS,
-	},
-	{
-		.compatible = "thine,thc63lvdm83d",
-		.data = (void *)DRM_MODE_CONNECTOR_LVDS,
-	},
+	{ .compatible = "lvds-decoder", .data = &decoder_data, },
+	{ .compatible = "lvds-encoder", .data = &encoder_data, },
+	{ .compatible = "thine,thc63lvdm83d", .data = &encoder_data, },
 	{},
 };
 MODULE_DEVICE_TABLE(of, lvds_codec_match);
-- 
2.29.2


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