[PATCH] drm/ast: Add Atomic gamma lut support for aspeed

[Jocelyn Falempe <jfalempe@xxxxxxxxxx>]

The current ast driver only supports legacy gamma interface.
This also fixes a Gnome3/Wayland error which incorrectly adds
gamma to atomic commit:
"Page flip discarded: CRTC property (GAMMA_LUT) not found"

I only tested remotely, so I wasn't able to check that it had
an effect on the VGA output. But when activating "Night Light"
in Gnome, ast_crtc_load_lut() is called.

Signed-off-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
---
 drivers/gpu/drm/ast/ast_mode.c | 35 +++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 214b10178454..0561fd7e7bb2 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -63,20 +63,23 @@ static inline void ast_load_palette_index(struct ast_private *ast,
 	ast_io_read8(ast, AST_IO_SEQ_PORT);
 }
 
-static void ast_crtc_load_lut(struct ast_private *ast, struct drm_crtc *crtc)
+static void ast_crtc_load_lut(struct ast_private *ast, struct drm_crtc_state *state)
 {
-	u16 *r, *g, *b;
 	int i;
 
-	if (!crtc->enabled)
-		return;
-
-	r = crtc->gamma_store;
-	g = r + crtc->gamma_size;
-	b = g + crtc->gamma_size;
+	if (state->gamma_lut) {
+		struct drm_color_lut *lut = (struct drm_color_lut *)state->gamma_lut->data;
 
-	for (i = 0; i < 256; i++)
-		ast_load_palette_index(ast, i, *r++ >> 8, *g++ >> 8, *b++ >> 8);
+		for (i = 0; i < 256; i++)
+			ast_load_palette_index(ast,
+				i,
+				lut[i].red >> 8,
+				lut[i].green >> 8,
+				lut[i].blue >> 8);
+	} else {
+		for (i = 0; i < 256; i++)
+			ast_load_palette_index(ast, i, i, i, i);
+	}
 }
 
 static bool ast_get_vbios_mode_info(const struct drm_format_info *format,
@@ -1019,8 +1022,7 @@ static void ast_crtc_dpms(struct drm_crtc *crtc, int mode)
 			ast_set_color_reg(ast, format);
 			ast_set_vbios_color_reg(ast, format, vbios_mode_info);
 		}
-
-		ast_crtc_load_lut(ast, crtc);
+		ast_crtc_load_lut(ast, crtc->state);
 		break;
 	case DRM_MODE_DPMS_STANDBY:
 	case DRM_MODE_DPMS_SUSPEND:
@@ -1158,20 +1160,17 @@ ast_crtc_helper_atomic_flush(struct drm_crtc *crtc,
 {
 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
 									  crtc);
-	struct drm_crtc_state *old_crtc_state = drm_atomic_get_old_crtc_state(state,
-									      crtc);
 	struct drm_device *dev = crtc->dev;
 	struct ast_private *ast = to_ast_private(dev);
 	struct ast_crtc_state *ast_crtc_state = to_ast_crtc_state(crtc_state);
-	struct ast_crtc_state *old_ast_crtc_state = to_ast_crtc_state(old_crtc_state);
 	struct ast_vbios_mode_info *vbios_mode_info = &ast_crtc_state->vbios_mode_info;
 
 	/*
 	 * The gamma LUT has to be reloaded after changing the primary
 	 * plane's color format.
 	 */
-	if (old_ast_crtc_state->format != ast_crtc_state->format)
-		ast_crtc_load_lut(ast, crtc);
+	if (crtc_state->enable && crtc_state->color_mgmt_changed)
+		ast_crtc_load_lut(ast, crtc_state);
 
 	//Set Aspeed Display-Port
 	if (ast->tx_chip_types & AST_TX_ASTDP_BIT)
@@ -1310,6 +1309,8 @@ static int ast_crtc_init(struct drm_device *dev)
 		return ret;
 
 	drm_mode_crtc_set_gamma_size(crtc, 256);
+	drm_crtc_enable_color_mgmt(crtc, 0, false, 256);
+
 	drm_crtc_helper_add(crtc, &ast_crtc_helper_funcs);
 
 	return 0;
-- 
2.37.3