[PATCH 2/5] drm/of: Add drm_of_dpi_get_color_coding()

Liu Ying
2025-03-04T10:14:45Z

Add helper function drm_of_dpi_get_color_coding() to get media bus format
value from MIPI DPI color coding string.

Signed-off-by: Liu Ying <victor.liu@nxp.com>
---
drivers/gpu/drm/drm_of.c | 43 ++++++++++++++++++++++++++++++++++++++++
include/drm/drm_of.h | 7 +++++++
2 files changed, 50 insertions(+)

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
index d0183dea7703..6e2e19275b99 100644
--- a/drivers/gpu/drm/drm_of.c
+++ b/drivers/gpu/drm/drm_of.c
@@ -285,6 +285,49 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
}
EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);

+/**
+ * drm_of_dpi_get_color_coding - Get DPI color coding
+ * @endpoint: DT endpoint node of the DPI source or sink
+ *
+ * Convert DT "dpi-color-coding" property string value into media bus format
+ * value.
+ *
+ * Return:
+ * * MEDIA_BUS_FMT_RGB565_1X16 - dpi-color-coding is "16bit-configuration1"
+ * * MEDIA_BUS_FMT_RGB565_1X24_CPADHI - dpi-color-coding is
+ * "16bit-configuration2"
+ * * MEDIA_BUS_FMT_RGB666_1X18 - dpi-color-coding is "18bit-configuration1"
+ * * MEDIA_BUS_FMT_BGR666_1X24_CPADHI - dpi-color-coding is
+ * "18bit-configuration2"
+ * * MEDIA_BUS_FMT_RGB888_1X24 - dpi-color-coding is "24bit"
+ * * -EINVAL - the "dpi-color-coding" property is unsupported
+ * * -ENODEV - the "dpi-color-coding" property is missing
+ */
+int drm_of_dpi_get_color_coding(const struct device_node *endpoint)
+{
+ const char *coding;
+ int ret;
+
+ ret = of_property_read_string(endpoint, "dpi-color-coding", &coding);
+ if (ret < 0)
+ return -ENODEV;
+
+ /* TODO: Add 16bit-configuration3 support. */
+ if (!strcmp(coding, "16bit-configuration1"))
+ return MEDIA_BUS_FMT_RGB565_1X16;
+ if (!strcmp(coding, "16bit-configuration2"))
+ return MEDIA_BUS_FMT_RGB565_1X24_CPADHI;
+ if (!strcmp(coding, "18bit-configuration1"))
+ return MEDIA_BUS_FMT_RGB666_1X18;
+ if (!strcmp(coding, "18bit-configuration2"))
+ return MEDIA_BUS_FMT_BGR666_1X24_CPADHI;
+ if (!strcmp(coding, "24bit"))
+ return MEDIA_BUS_FMT_RGB888_1X24;
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(drm_of_dpi_get_color_coding);
+
enum drm_of_lvds_pixels {
DRM_OF_LVDS_EVEN = BIT(0),
DRM_OF_LVDS_ODD = BIT(1),
diff --git a/include/drm/drm_of.h b/include/drm/drm_of.h
index 7f0256dae3f1..0a827f3b3a55 100644
--- a/include/drm/drm_of.h
+++ b/include/drm/drm_of.h
@@ -50,6 +50,7 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
int port, int endpoint,
struct drm_panel **panel,
struct drm_bridge **bridge);
+int drm_of_dpi_get_color_coding(const struct device_node *endpoint);
int drm_of_lvds_get_dual_link_pixel_order(const struct device_node *port1,
const struct device_node *port2);
int drm_of_lvds_get_dual_link_pixel_order_sink(struct device_node *port1,
@@ -104,6 +105,12 @@ static inline int drm_of_find_panel_or_bridge(const struct device_node *np,
return -EINVAL;
}

+static inline int
+drm_of_dpi_get_color_coding(const struct device_node *endpoint)
+{
+ return -EINVAL;
+}
+
static inline int
drm_of_lvds_get_dual_link_pixel_order(const struct device_node *port1,
const struct device_node *port2)
--
2.34.1