drm/ast: Inline ast_crtc_dpms() into callers

The function ast_crtc_dpms() is left over from when the ast driver
did not implement atomic modesetting. But DPMS is not supported by
atomic modesetting and the helper is only called to enable or
disable the CRTC sync pulses. Inline the function into its callers.

To disable the CRTC, ast sets (AST_DPMS_VSYNC_OFF | AST_DPMS_HSYNC_OFF)
in VGACRB6. Replace the constants with the correct register constants
for VGACRB6.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240627153638.8765-8-tzimmermann@suse.de

drivers/gpu/drm/ast/ast_mode.c

@@ -1019,29 +1019,6 @@ static int ast_cursor_plane_init(struct ast_device *ast)
  * CRTC
  */
 
-static void ast_crtc_dpms(struct drm_crtc *crtc, int mode)
-{
-	struct ast_device *ast = to_ast_device(crtc->dev);
-	u8 ch = AST_DPMS_VSYNC_OFF | AST_DPMS_HSYNC_OFF;
-
-	/* TODO: Maybe control display signal generation with
-	 *       Sync Enable (bit CR17.7).
-	 */
-	switch (mode) {
-	case DRM_MODE_DPMS_ON:
-		ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0xfc, 0);
-		ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, 0);
-		break;
-	case DRM_MODE_DPMS_STANDBY:
-	case DRM_MODE_DPMS_SUSPEND:
-	case DRM_MODE_DPMS_OFF:
-		ch = mode;
-		ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, AST_IO_VGASR1_SD);
-		ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0xfc, ch);
-		break;
-	}
-}
-
 static enum drm_mode_status
 ast_crtc_helper_mode_valid(struct drm_crtc *crtc, const struct drm_display_mode *mode)
 {
@@ -1217,14 +1194,23 @@ ast_crtc_helper_atomic_flush(struct drm_crtc *crtc,
 
 static void ast_crtc_helper_atomic_enable(struct drm_crtc *crtc, struct drm_atomic_state *state)
 {
-	ast_crtc_dpms(crtc, DRM_MODE_DPMS_ON);
+	struct ast_device *ast = to_ast_device(crtc->dev);
+
+	ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0xfc, 0x00);
+	ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, 0x00);
 }
 
 static void ast_crtc_helper_atomic_disable(struct drm_crtc *crtc, struct drm_atomic_state *state)
 {
 	struct drm_crtc_state *old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc);
+	struct ast_device *ast = to_ast_device(crtc->dev);
+	u8 vgacrb6;
+
+	ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, AST_IO_VGASR1_SD);
 
-	ast_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
+	vgacrb6 = AST_IO_VGACRB6_VSYNC_OFF |
+		  AST_IO_VGACRB6_HSYNC_OFF;
+	ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0xfc, vgacrb6);
 
 	/*
 	 * HW cursors require the underlying primary plane and CRTC to

drivers/gpu/drm/ast/ast_reg.h

@@ -32,6 +32,8 @@
 #define AST_IO_VGACR80_PASSWORD		(0xa8)
 #define AST_IO_VGACRA1_VGAIO_DISABLED	BIT(1)
 #define AST_IO_VGACRA1_MMIO_ENABLED	BIT(2)
+#define AST_IO_VGACRB6_HSYNC_OFF	BIT(0)
+#define AST_IO_VGACRB6_VSYNC_OFF	BIT(1)
 #define AST_IO_VGACRCB_HWC_16BPP	BIT(0) /* set: ARGB4444, cleared: 2bpp palette */
 #define AST_IO_VGACRCB_HWC_ENABLED	BIT(1)
 
@@ -76,13 +78,6 @@
 #define ASTDP_HOST_EDID_READ_DONE	BIT(0)
 #define ASTDP_HOST_EDID_READ_DONE_MASK	GENMASK(0, 0)
 
-/*
- * CRB8[b1]: Enable VSYNC off
- * CRB8[b0]: Enable HSYNC off
- */
-#define AST_DPMS_VSYNC_OFF		BIT(1)
-#define AST_DPMS_HSYNC_OFF		BIT(0)
-
 /*
  * CRDF[b4]: Mirror of AST_DP_VIDEO_ENABLE
  * Precondition:	A. ~AST_DP_PHY_SLEEP  &&