drm/sysfb: Find screen_info format with helpers

Convert drm_sysfb_get_format_si() to lookup the screen_info color
format as struct pixel_format with screen_info_pixel_format(). Then
search the list of given formats for the screen_info format with
pixel_format_equal().

Replaces custom code with helpers. The pixel-compare helper
pixel_format_equal() also handles indexed color formats. Prepares
for sysfb drivers to support color palettes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250714151513.309475-4-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c b/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c
index 0b3fb874a51f2038671de8aba61fc3e17338bb45..885864168c54fa3f0c8d115001fe3e0406663312 100644 (file)
--- a/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c
+++ b/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c
@@ -79,22 +79,19 @@ const struct drm_format_info *drm_sysfb_get_format_si(struct drm_device *dev,
                                                      const struct screen_info *si)
 {
        const struct drm_format_info *format = NULL;
-       u32 bits_per_pixel;
+       struct pixel_format pixel;
        size_t i;
+       int ret;
 
-       bits_per_pixel = __screen_info_lfb_bits_per_pixel(si);
+       ret = screen_info_pixel_format(si, &pixel);
+       if (ret)
+               return NULL;
 
        for (i = 0; i < nformats; ++i) {
-               const struct pixel_format *f = &formats[i].pixel;
-
-               if (bits_per_pixel == f->bits_per_pixel &&
-                   si->red_size == f->red.length &&
-                   si->red_pos == f->red.offset &&
-                   si->green_size == f->green.length &&
-                   si->green_pos == f->green.offset &&
-                   si->blue_size == f->blue.length &&
-                   si->blue_pos == f->blue.offset) {
-                       format = drm_format_info(formats[i].fourcc);
+               const struct drm_sysfb_format *f = &formats[i];
+
+               if (pixel_format_equal(&pixel, &f->pixel)) {
+                       format = drm_format_info(f->fourcc);
                        break;
                }
        }