Add helper drm_crtc_fill_palette_332(), which fills palettes with
RGB332 color data. Each color in RGB332 format serves as an index
into an 8-bit palette that stores the corresponding component-based
colors.
Vesadrm will use the new helper to emulate RGB formats on top of
framebuffers in C8 format.
v2:
- add comments on bit operations (Javier)
Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
Reviewed-by: Javier Martinez Canillas <javi...@redhat.com>
---
drivers/gpu/drm/drm_color_mgmt.c | 34 ++++++++++++++++++++++++++++++++
include/drm/drm_color_mgmt.h | 1 +
2 files changed, 35 insertions(+)
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index 37a3270bc3c2..131c1c9ae92f 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -817,6 +817,40 @@ void drm_crtc_load_palette_8(struct drm_crtc *crtc, const
struct drm_color_lut *
}
EXPORT_SYMBOL(drm_crtc_load_palette_8);
+static void fill_palette_332(struct drm_crtc *crtc, u16 r, u16 g, u16 b,
+ drm_crtc_set_lut_func set_palette)
+{
+ unsigned int i = (r << 5) | (g << 2) | b; /* 8-bit palette index */
+
+ /* Expand R (3-bit) G (3-bit) and B (2-bit) values to 16-bit values */
+ r = (r << 13) | (r << 10) | (r << 7) | (r << 4) | (r << 1) | (r >> 2);
+ g = (g << 13) | (g << 10) | (g << 7) | (g << 4) | (g << 1) | (g >> 2);
+ b = (b << 14) | (b << 12) | (b << 10) | (b << 8) | (b << 6) | (b << 4)
| (b << 2) | b;
+
+ set_palette(crtc, i, r, g, b);
+}
+
+/**
+ * drm_crtc_fill_palette_332 - Programs a default palette for R332-like formats
+ * @crtc: The displaying CRTC
+ * @set_palette: Callback for programming the hardware gamma LUT
+ *
+ * Programs an RGB332 palette to hardware.
+ */
+void drm_crtc_fill_palette_332(struct drm_crtc *crtc, drm_crtc_set_lut_func
set_palette)
+{
+ unsigned int r, g, b;
+
+ /* Limits of 8-8-4 are the maximum number of values for each channel. */
+ for (r = 0; r < 8; ++r) {
+ for (g = 0; g < 8; ++g) {
+ for (b = 0; b < 4; ++b)
+ fill_palette_332(crtc, r, g, b, set_palette);
+ }
+ }
+}
+EXPORT_SYMBOL(drm_crtc_fill_palette_332);
+
static void fill_palette_8(struct drm_crtc *crtc, unsigned int i,
drm_crtc_set_lut_func set_palette)
{
diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
index 6cb577f6dba6..eccb71ab335a 100644
--- a/include/drm/drm_color_mgmt.h
+++ b/include/drm/drm_color_mgmt.h
@@ -143,6 +143,7 @@ void drm_crtc_fill_gamma_555(struct drm_crtc *crtc,
drm_crtc_set_lut_func set_ga
void drm_crtc_load_palette_8(struct drm_crtc *crtc, const struct drm_color_lut
*lut,
drm_crtc_set_lut_func set_palette);
+void drm_crtc_fill_palette_332(struct drm_crtc *crtc, drm_crtc_set_lut_func
set_palette);
void drm_crtc_fill_palette_8(struct drm_crtc *crtc, drm_crtc_set_lut_func
set_palette);
#endif
--
2.50.0
