Commit 067ae3a7 authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

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



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: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarJocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20250520094203.30545-3-tzimmermann@suse.de
parent e6469324

drivers/gpu/drm/ast/ast_mode.c

+42 −27
Original line number Diff line number Diff line
@@ -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,

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,

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_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);

	}

}