drm/sysfb: Generalize pixel-format matching

Provide drm_sysfb_get_format(), a helper that finds a specific DRM
format from a list of pixel formats. The new function builds upon
drm_sysfb_get_format_si(), which finds the DRM format from a given
instance of struct screen_info. Now get the screen_info's pixel format
in the caller. Allows for matching pixel formats in drivers without
screen_info.

Convert the callers in efidrm and vesadrm to the new interface.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Julius Werner <jwerner@chromium.org>
Link: https://patch.msgid.link/20260217155836.96267-11-tzimmermann@suse.de

1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/gpu/drm/sysfb/drm_sysfb.c b/drivers/gpu/drm/sysfb/drm_sysfb.c
index 308f82153b15..fbfb37d0fae1 100644
--- a/drivers/gpu/drm/sysfb/drm_sysfb.c
+++ b/drivers/gpu/drm/sysfb/drm_sysfb.c
@@ -31,5 +31,29 @@ int drm_sysfb_get_validated_int0(struct drm_device *dev, const char *name,
 }
 EXPORT_SYMBOL(drm_sysfb_get_validated_int0);
 
+const struct drm_format_info *drm_sysfb_get_format(struct drm_device *dev,
+						   const struct drm_sysfb_format *formats,
+						   size_t nformats,
+						   const struct pixel_format *pixel)
+{
+	const struct drm_format_info *format = NULL;
+	size_t i;
+
+	for (i = 0; i < nformats; ++i) {
+		const struct drm_sysfb_format *f = &formats[i];
+
+		if (pixel_format_equal(pixel, &f->pixel)) {
+			format = drm_format_info(f->fourcc);
+			break;
+		}
+	}
+
+	if (!format)
+		drm_warn(dev, "No compatible color format found\n");
+
+	return format;
+}
+EXPORT_SYMBOL(drm_sysfb_get_format);
+
 MODULE_DESCRIPTION("Helpers for DRM sysfb drivers");
 MODULE_LICENSE("GPL");