[PATCH v4 08/11] drm/mipi-dsi: Add helper to find input format

[Aradhya Bhatia]

Add a helper API that can be used by the DSI hosts to find the required
input bus format for the given output dsi pixel format.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
Signed-off-by: Aradhya Bhatia <a-bhatia1 at ti.com>
---
 drivers/gpu/drm/drm_mipi_dsi.c | 37 ++++++++++++++++++++++++++++++++++
 include/drm/drm_mipi_dsi.h     |  1 +
 2 files changed, 38 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index a471c46f5ca6..937aa16dfcf6 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -36,6 +36,8 @@
 #include <drm/drm_mipi_dsi.h>
 #include <drm/drm_print.h>
 
+#include <linux/media-bus-format.h>
+
 #include <video/mipi_display.h>
 
 /**
@@ -866,6 +868,41 @@ ssize_t mipi_dsi_generic_read(struct mipi_dsi_device *dsi, const void *params,
 }
 EXPORT_SYMBOL(mipi_dsi_generic_read);
 
+/**
+ * drm_mipi_dsi_get_input_bus_fmt() - Get the required MEDIA_BUS_FMT_* based
+ *				      input pixel format for a given DSI output
+ *				      pixel format
+ * @dsi_format: pixel format that a DSI host needs to output
+ *
+ * Various DSI hosts can use this function during their
+ * &drm_bridge_funcs.atomic_get_input_bus_fmts operation to ascertain
+ * the MEDIA_BUS_FMT_* pixel format required as input.
+ *
+ * RETURNS:
+ * a 32-bit MEDIA_BUS_FMT_* value on success or 0 in case of failure.
+ */
+u32 drm_mipi_dsi_get_input_bus_fmt(enum mipi_dsi_pixel_format dsi_format)
+{
+	switch (dsi_format) {
+	case MIPI_DSI_FMT_RGB888:
+		return MEDIA_BUS_FMT_RGB888_1X24;
+
+	case MIPI_DSI_FMT_RGB666:
+		return MEDIA_BUS_FMT_RGB666_1X24_CPADHI;
+
+	case MIPI_DSI_FMT_RGB666_PACKED:
+		return MEDIA_BUS_FMT_RGB666_1X18;
+
+	case MIPI_DSI_FMT_RGB565:
+		return MEDIA_BUS_FMT_RGB565_1X16;
+
+	default:
+		/* Unsupported DSI Format */
+		return 0;
+	}
+}
+EXPORT_SYMBOL(drm_mipi_dsi_get_input_bus_fmt);
+
 /**
  * mipi_dsi_dcs_write_buffer() - transmit a DCS command with payload
  * @dsi: DSI peripheral device
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 71d121aeef24..78a2c7d9eefb 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -290,6 +290,7 @@ void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
 				  const void *payload, size_t size);
 ssize_t mipi_dsi_generic_read(struct mipi_dsi_device *dsi, const void *params,
 			      size_t num_params, void *data, size_t size);
+u32 drm_mipi_dsi_get_input_bus_fmt(enum mipi_dsi_pixel_format dsi_format);
 
 #define mipi_dsi_msleep(ctx, delay)	\
 	do {				\
-- 
2.34.1