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drm/ast: Use helpers for programming gamma ramps and palettes

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Replace ast's code for programming the hardware gamma/palette LUT
with DRM helpers. Either load provided data or program a default.
Set the individual entries with a callback.

Each gamma/palette value is given as 3 individual 16-bit values
for red, green and blue. The driver reduces them to 8 bit to make
them fit into hardware registers.

v3:
- fix tags (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20250520094203.30545-3-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann 2025-05-20 11:40:04 +02:00
parent e64693248f
commit 067ae3a705
1 changed files with 42 additions and 27 deletions
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69
drivers/gpu/drm/ast/ast_mode.c
View File

@ -34,6 +34,7 @@
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_color_mgmt.h>
#include <drm/drm_crtc.h>
#include <drm/drm_damage_helper.h>
#include <drm/drm_format_helper.h>
@ -71,31 +72,44 @@ static unsigned long ast_fb_vram_size(struct ast_device *ast)
return cursor_offset - offset;
}
static inline void ast_load_palette_index(struct ast_device *ast,
u8 index, u8 red, u8 green,
u8 blue)
static void ast_set_gamma_lut(struct drm_crtc *crtc, unsigned int index,
u16 red, u16 green, u16 blue)
{
ast_io_write8(ast, AST_IO_VGADWR, index);
struct drm_device *dev = crtc->dev;
struct ast_device *ast = to_ast_device(dev);
u8 i8 = index & 0xff;
u8 r8 = red >> 8;
u8 g8 = green >> 8;
u8 b8 = blue >> 8;
if (drm_WARN_ON_ONCE(dev, index != i8))
return; /* driver bug */
ast_io_write8(ast, AST_IO_VGADWR, i8);
ast_io_read8(ast, AST_IO_VGASRI);
ast_io_write8(ast, AST_IO_VGAPDR, red);
ast_io_write8(ast, AST_IO_VGAPDR, r8);
ast_io_read8(ast, AST_IO_VGASRI);
ast_io_write8(ast, AST_IO_VGAPDR, green);
ast_io_write8(ast, AST_IO_VGAPDR, g8);
ast_io_read8(ast, AST_IO_VGASRI);
ast_io_write8(ast, AST_IO_VGAPDR, blue);
ast_io_write8(ast, AST_IO_VGAPDR, b8);
ast_io_read8(ast, AST_IO_VGASRI);
}
static void ast_crtc_set_gamma_linear(struct ast_device *ast,
const struct drm_format_info *format)
static void ast_crtc_fill_gamma(struct ast_device *ast,
const struct drm_format_info *format)
{
int i;
struct drm_crtc *crtc = &ast->crtc;
switch (format->format) {
case DRM_FORMAT_C8: /* In this case, gamma table is used as color palette */
case DRM_FORMAT_C8:
/* gamma table is used as color palette */
drm_crtc_fill_palette_8(crtc, ast_set_gamma_lut);
break;
case DRM_FORMAT_RGB565:
/* also uses 8-bit gamma ramp on low-color modes */
fallthrough;
case DRM_FORMAT_XRGB8888:
for (i = 0; i < AST_LUT_SIZE; i++)
ast_load_palette_index(ast, i, i, i, i);
drm_crtc_fill_gamma_888(crtc, ast_set_gamma_lut);
break;
default:
drm_warn_once(&ast->base, "Unsupported format %p4cc for gamma correction\n",
@ -104,21 +118,22 @@ static void ast_crtc_set_gamma_linear(struct ast_device *ast,
}
}
static void ast_crtc_set_gamma(struct ast_device *ast,
const struct drm_format_info *format,
struct drm_color_lut *lut)
static void ast_crtc_load_gamma(struct ast_device *ast,
const struct drm_format_info *format,
struct drm_color_lut *lut)
{
int i;
struct drm_crtc *crtc = &ast->crtc;
switch (format->format) {
case DRM_FORMAT_C8: /* In this case, gamma table is used as color palette */
case DRM_FORMAT_C8:
/* gamma table is used as color palette */
drm_crtc_load_palette_8(crtc, lut, ast_set_gamma_lut);
break;
case DRM_FORMAT_RGB565:
/* also uses 8-bit gamma ramp on low-color modes */
fallthrough;
case DRM_FORMAT_XRGB8888:
for (i = 0; i < AST_LUT_SIZE; i++)
ast_load_palette_index(ast, i,
lut[i].red >> 8,
lut[i].green >> 8,
lut[i].blue >> 8);
drm_crtc_load_gamma_888(crtc, lut, ast_set_gamma_lut);
break;
default:
drm_warn_once(&ast->base, "Unsupported format %p4cc for gamma correction\n",
@ -811,11 +826,11 @@ ast_crtc_helper_atomic_flush(struct drm_crtc *crtc,
*/
if (crtc_state->enable && crtc_state->color_mgmt_changed) {
if (crtc_state->gamma_lut)
ast_crtc_set_gamma(ast,
ast_crtc_state->format,
crtc_state->gamma_lut->data);
ast_crtc_load_gamma(ast,
ast_crtc_state->format,
crtc_state->gamma_lut->data);
else
ast_crtc_set_gamma_linear(ast, ast_crtc_state->format);
ast_crtc_fill_gamma(ast, ast_crtc_state->format);
}
}