drm/bridge: lvds-codec: Add support for LVDS data mapping select

Decoder input LVDS format is a property of the decoder chip or even
its strapping. Handle data-mapping the same way lvds-panel does. In
case data-mapping is not present, do nothing, since there are still
legacy bindings which do not specify this property.
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
To: dri-devel@lists.freedesktop.org
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211010144919.38392-2-marex@denx.de

drivers/gpu/drm/bridge/lvds-codec.c

@@ -12,6 +12,7 @@
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 
+#include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_panel.h>
 
@@ -22,6 +23,7 @@ struct lvds_codec {
 	struct regulator *vcc;
 	struct gpio_desc *powerdown_gpio;
 	u32 connector_type;
+	unsigned int bus_format;
 };
 
 static inline struct lvds_codec *to_lvds_codec(struct drm_bridge *bridge)
@@ -74,12 +76,50 @@ static const struct drm_bridge_funcs funcs = {
 	.disable = lvds_codec_disable,
 };
 
+#define MAX_INPUT_SEL_FORMATS 1
+static u32 *
+lvds_codec_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
+				     struct drm_bridge_state *bridge_state,
+				     struct drm_crtc_state *crtc_state,
+				     struct drm_connector_state *conn_state,
+				     u32 output_fmt,
+				     unsigned int *num_input_fmts)
+{
+	struct lvds_codec *lvds_codec = to_lvds_codec(bridge);
+	u32 *input_fmts;
+
+	*num_input_fmts = 0;
+
+	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
+			     GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	input_fmts[0] = lvds_codec->bus_format;
+	*num_input_fmts = MAX_INPUT_SEL_FORMATS;
+
+	return input_fmts;
+}
+
+static const struct drm_bridge_funcs funcs_decoder = {
+	.attach = lvds_codec_attach,
+	.enable = lvds_codec_enable,
+	.disable = lvds_codec_disable,
+	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+	.atomic_reset = drm_atomic_helper_bridge_reset,
+	.atomic_get_input_bus_fmts = lvds_codec_atomic_get_input_bus_fmts,
+};
+
 static int lvds_codec_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *panel_node;
+	struct device_node *bus_node;
 	struct drm_panel *panel;
 	struct lvds_codec *lvds_codec;
+	const char *mapping;
+	int ret;
 
 	lvds_codec = devm_kzalloc(dev, sizeof(*lvds_codec), GFP_KERNEL);
 	if (!lvds_codec)
@@ -119,13 +159,47 @@ static int lvds_codec_probe(struct platform_device *pdev)
 	if (IS_ERR(lvds_codec->panel_bridge))
 		return PTR_ERR(lvds_codec->panel_bridge);
 
+	lvds_codec->bridge.funcs = &funcs;
+
+	/*
+	 * Decoder input LVDS format is a property of the decoder chip or even
+	 * its strapping. Handle data-mapping the same way lvds-panel does. In
+	 * case data-mapping is not present, do nothing, since there are still
+	 * legacy bindings which do not specify this property.
+	 */
+	if (lvds_codec->connector_type != DRM_MODE_CONNECTOR_LVDS) {
+		bus_node = of_graph_get_endpoint_by_regs(dev->of_node, 0, 0);
+		if (!bus_node) {
+			dev_dbg(dev, "bus DT node not found\n");
+			return -ENXIO;
+		}
+
+		ret = of_property_read_string(bus_node, "data-mapping",
+					      &mapping);
+		of_node_put(bus_node);
+		if (ret < 0) {
+			dev_warn(dev, "missing 'data-mapping' DT property\n");
+		} else {
+			if (!strcmp(mapping, "jeida-18")) {
+				lvds_codec->bus_format = MEDIA_BUS_FMT_RGB666_1X7X3_SPWG;
+			} else if (!strcmp(mapping, "jeida-24")) {
+				lvds_codec->bus_format = MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA;
+			} else if (!strcmp(mapping, "vesa-24")) {
+				lvds_codec->bus_format = MEDIA_BUS_FMT_RGB888_1X7X4_SPWG;
+			} else {
+				dev_err(dev, "invalid 'data-mapping' DT property\n");
+				return -EINVAL;
+			}
+			lvds_codec->bridge.funcs = &funcs_decoder;
+		}
+	}
+
 	/*
 	 * 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.
 	 */
 	lvds_codec->bridge.of_node = dev->of_node;
-	lvds_codec->bridge.funcs = &funcs;
 	drm_bridge_add(&lvds_codec->bridge);
 
 	platform_set_drvdata(pdev, lvds_codec);