[PATCH v4 1/3] drm: add bus_formats and num_bus_formats fields to drm_display_info

[Boris Brezillon]

Add bus_formats and num_bus_formats fields and
drm_display_info_set_bus_formats helper function to specify the bus
formats supported by a given display.

This information can be used by display controller drivers to configure
the output interface appropriately (i.e. RGB565, RGB666 or RGB888 on raw
RGB or LVDS busses).

Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
---
 drivers/gpu/drm/drm_crtc.c | 32 ++++++++++++++++++++++++++++++++
 include/drm/drm_crtc.h     |  7 +++++++
 2 files changed, 39 insertions(+)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index e79c8d3..d3b7ed0 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -763,6 +763,38 @@ static void drm_mode_remove(struct drm_connector 
*connector,
        drm_mode_destroy(connector->dev, mode);
 }

+/*
+ * drm_display_info_set_bus_formats - set the supported bus formats
+ * @info: display info to store bus formats in
+ * @fmts: array containing the supported bus formats
+ * @nfmts: the number of entries in the fmts array
+ *
+ * Store the suppported bus formats in display info structure.
+ * See MEDIA_BUS_FMT_* definitions in include/uapi/linux/media-bus-format.h for
+ * a full list of available formats.
+ */
+int drm_display_info_set_bus_formats(struct drm_display_info *info, const u32 
*fmts,
+                                    unsigned int num_fmts)
+{
+       u32 *formats = NULL;
+
+       if (!fmts && num_fmts)
+               return -EINVAL;
+
+       if (fmts && num_fmts) {
+               formats = kmemdup(fmts, sizeof(*fmts) * num_fmts, GFP_KERNEL);
+               if (!formats)
+                       return -ENOMEM;
+       }
+
+       kfree(info->bus_formats);
+       info->bus_formats = formats;
+       info->num_bus_formats = num_fmts;
+
+       return 0;
+}
+EXPORT_SYMBOL(drm_display_info_set_bus_formats);
+
 /**
  * drm_connector_get_cmdline_mode - reads the user's cmdline mode
  * @connector: connector to quwery
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index c40070a..a35844f 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -31,6 +31,7 @@
 #include <linux/idr.h>
 #include <linux/fb.h>
 #include <linux/hdmi.h>
+#include <linux/media-bus-format.h>
 #include <uapi/drm/drm_mode.h>
 #include <uapi/drm/drm_fourcc.h>
 #include <drm/drm_modeset_lock.h>
@@ -130,6 +131,9 @@ struct drm_display_info {
        enum subpixel_order subpixel_order;
        u32 color_formats;

+       const u32 *bus_formats;
+       unsigned int num_bus_formats;
+
        /* Mask of supported hdmi deep color modes */
        u8 edid_hdmi_dc_modes;

@@ -982,6 +986,9 @@ extern int drm_mode_connector_set_path_property(struct 
drm_connector *connector,
 extern int drm_mode_connector_update_edid_property(struct drm_connector 
*connector,
                                                struct edid *edid);

+extern int drm_display_info_set_bus_formats(struct drm_display_info *info,
+                                           const u32 *fmts, unsigned int 
nfmts);
+
 static inline bool drm_property_type_is(struct drm_property *property,
                uint32_t type)
 {
-- 
1.9.1