drm: rcar-du: Refactor DEFR8 feature

Rename the feature from RCAR_DU_FEATURE_DEFR8 to
RCAR_DU_FEATURE_EXT_CTRL_REGS to cover all extended control registers in
addition to the DEFR8 register.

Usage of the feature is refactored to optimize runtime operation and
prepare for external clock support.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/rcar_du_crtc.c

@@ -139,9 +139,10 @@ void rcar_du_crtc_route_output(struct drm_crtc *crtc,
 	 */
 	rcrtc->outputs |= BIT(output);
 
-	/* Store RGB routing to DPAD0 for R8A7790. */
-	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_DEFR8) &&
-	    output == RCAR_DU_OUTPUT_DPAD0)
+	/* Store RGB routing to DPAD0, the hardware will be configured when
+	 * starting the CRTC.
+	 */
+	if (output == RCAR_DU_OUTPUT_DPAD0)
 		rcdu->dpad0_source = rcrtc->index;
 }
 

drivers/gpu/drm/rcar-du/rcar_du_drv.c

@@ -56,7 +56,8 @@ static const struct rcar_du_device_info rcar_du_r8a7779_info = {
 };
 
 static const struct rcar_du_device_info rcar_du_r8a7790_info = {
-	.features = RCAR_DU_FEATURE_CRTC_IRQ_CLOCK | RCAR_DU_FEATURE_DEFR8,
+	.features = RCAR_DU_FEATURE_CRTC_IRQ_CLOCK
+		  | RCAR_DU_FEATURE_EXT_CTRL_REGS,
 	.quirks = RCAR_DU_QUIRK_ALIGN_128B | RCAR_DU_QUIRK_LVDS_LANES,
 	.num_crtcs = 3,
 	.routes = {
@@ -83,7 +84,8 @@ static const struct rcar_du_device_info rcar_du_r8a7790_info = {
 };
 
 static const struct rcar_du_device_info rcar_du_r8a7791_info = {
-	.features = RCAR_DU_FEATURE_CRTC_IRQ_CLOCK | RCAR_DU_FEATURE_DEFR8,
+	.features = RCAR_DU_FEATURE_CRTC_IRQ_CLOCK
+		  | RCAR_DU_FEATURE_EXT_CTRL_REGS,
 	.num_crtcs = 2,
 	.routes = {
 		/* R8A7791 has one RGB output, one LVDS output and one

drivers/gpu/drm/rcar-du/rcar_du_drv.h

@@ -27,7 +27,7 @@ struct rcar_du_device;
 struct rcar_du_lvdsenc;
 
 #define RCAR_DU_FEATURE_CRTC_IRQ_CLOCK	(1 << 0)	/* Per-CRTC IRQ and clock */
-#define RCAR_DU_FEATURE_DEFR8		(1 << 1)	/* Has DEFR8 register */
+#define RCAR_DU_FEATURE_EXT_CTRL_REGS	(1 << 1)	/* Has extended control registers */
 
 #define RCAR_DU_QUIRK_ALIGN_128B	(1 << 0)	/* Align pitches to 128 bytes */
 #define RCAR_DU_QUIRK_LVDS_LANES	(1 << 1)	/* LVDS lanes 1 and 3 inverted */

drivers/gpu/drm/rcar-du/rcar_du_group.c

@@ -48,9 +48,6 @@ static void rcar_du_group_setup_defr8(struct rcar_du_group *rgrp)
 {
 	u32 defr8 = DEFR8_CODE | DEFR8_DEFE8;
 
-	if (!rcar_du_has(rgrp->dev, RCAR_DU_FEATURE_DEFR8))
-		return;
-
 	/* The DEFR8 register for the first group also controls RGB output
 	 * routing to DPAD0
 	 */
@@ -69,7 +66,8 @@ static void rcar_du_group_setup(struct rcar_du_group *rgrp)
 	rcar_du_group_write(rgrp, DEFR4, DEFR4_CODE);
 	rcar_du_group_write(rgrp, DEFR5, DEFR5_CODE | DEFR5_DEFE5);
 
-	rcar_du_group_setup_defr8(rgrp);
+	if (rcar_du_has(rgrp->dev, RCAR_DU_FEATURE_EXT_CTRL_REGS))
+		rcar_du_group_setup_defr8(rgrp);
 
 	/* Use DS1PR and DS2PR to configure planes priorities and connects the
 	 * superposition 0 to DU0 pins. DU1 pins will be configured dynamically.
@@ -149,6 +147,9 @@ static int rcar_du_set_dpad0_routing(struct rcar_du_device *rcdu)
 {
 	int ret;
 
+	if (!rcar_du_has(rcdu, RCAR_DU_FEATURE_EXT_CTRL_REGS))
+		return 0;
+
 	/* RGB output routing to DPAD0 is configured in the DEFR8 register of
 	 * the first group. As this function can be called with the DU0 and DU1
 	 * CRTCs disabled, we need to enable the first group clock before