drm/fbdev-helper: Move color-mode lookup into 4CC format helper

The color mode as specified on the kernel command line gives the user's
preferred color depth and number of bits per pixel. Move the
color-mode-to-format conversion from fbdev helpers into a 4CC helper,
so that it can be shared among DRM clients.

v2:
- fix grammar in commit message (Laurent)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240924071734.98201-2-tzimmermann@suse.de

1 files changed, 15 insertions, 55 deletions

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 29c53f9f449c..af1fe79c701d 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1441,67 +1441,27 @@ unlock:
 EXPORT_SYMBOL(drm_fb_helper_pan_display);
 
 static uint32_t drm_fb_helper_find_format(struct drm_fb_helper *fb_helper, const uint32_t *formats,
-					  size_t format_count, uint32_t bpp, uint32_t depth)
+					  size_t format_count, unsigned int color_mode)
 {
 	struct drm_device *dev = fb_helper->dev;
 	uint32_t format;
 	size_t i;
 
-	/*
-	 * Do not consider YUV or other complicated formats
-	 * for framebuffers. This means only legacy formats
-	 * are supported (fmt->depth is a legacy field), but
-	 * the framebuffer emulation can only deal with such
-	 * formats, specifically RGB/BGA formats.
-	 */
-	format = drm_mode_legacy_fb_format(bpp, depth);
-	if (!format)
-		goto err;
+	format = drm_driver_color_mode_format(dev, color_mode);
+	if (!format) {
+		drm_info(dev, "unsupported color mode of %d\n", color_mode);
+		return DRM_FORMAT_INVALID;
+	}
 
 	for (i = 0; i < format_count; ++i) {
 		if (formats[i] == format)
 			return format;
 	}
-
-err:
-	/* We found nothing. */
-	drm_warn(dev, "bpp/depth value of %u/%u not supported\n", bpp, depth);
+	drm_warn(dev, "format %p4cc not supported\n", &format);
 
 	return DRM_FORMAT_INVALID;
 }
 
-static uint32_t drm_fb_helper_find_color_mode_format(struct drm_fb_helper *fb_helper,
-						     const uint32_t *formats, size_t format_count,
-						     unsigned int color_mode)
-{
-	struct drm_device *dev = fb_helper->dev;
-	uint32_t bpp, depth;
-
-	switch (color_mode) {
-	case 1:
-	case 2:
-	case 4:
-	case 8:
-	case 16:
-	case 24:
-		bpp = depth = color_mode;
-		break;
-	case 15:
-		bpp = 16;
-		depth = 15;
-		break;
-	case 32:
-		bpp = 32;
-		depth = 24;
-		break;
-	default:
-		drm_info(dev, "unsupported color mode of %d\n", color_mode);
-		return DRM_FORMAT_INVALID;
-	}
-
-	return drm_fb_helper_find_format(fb_helper, formats, format_count, bpp, depth);
-}
-
 static int __drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
 				      struct drm_fb_helper_surface_size *sizes)
 {
@@ -1531,10 +1491,10 @@ static int __drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
 			if (!cmdline_mode->bpp_specified)
 				continue;
 
-			surface_format = drm_fb_helper_find_color_mode_format(fb_helper,
-									      plane->format_types,
-									      plane->format_count,
-									      cmdline_mode->bpp);
+			surface_format = drm_fb_helper_find_format(fb_helper,
+								   plane->format_types,
+								   plane->format_count,
+								   cmdline_mode->bpp);
 			if (surface_format != DRM_FORMAT_INVALID)
 				break; /* found supported format */
 		}
@@ -1544,10 +1504,10 @@ static int __drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
 			break; /* found supported format */
 
 		/* try preferred color mode */
-		surface_format = drm_fb_helper_find_color_mode_format(fb_helper,
-								      plane->format_types,
-								      plane->format_count,
-								      fb_helper->preferred_bpp);
+		surface_format = drm_fb_helper_find_format(fb_helper,
+							   plane->format_types,
+							   plane->format_count,
+							   fb_helper->preferred_bpp);
 		if (surface_format != DRM_FORMAT_INVALID)
 			break; /* found supported format */
 	}