drm/bridge: ti-sn65dsi83: Add vcc supply regulator support

VCC needs to be enabled before releasing the enable GPIO.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211213133626.2498056-5-alexander.stein@ew.tq-group.com

drivers/gpu/drm/bridge/ti-sn65dsi83.c

@@ -33,6 +33,7 @@
 #include <linux/of_device.h>
 #include <linux/of_graph.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
@@ -143,6 +144,7 @@ struct sn65dsi83 {
 	struct mipi_dsi_device		*dsi;
 	struct drm_bridge		*panel_bridge;
 	struct gpio_desc		*enable_gpio;
+	struct regulator		*vcc;
 	int				dsi_lanes;
 	bool				lvds_dual_link;
 	bool				lvds_dual_link_even_odd_swap;
@@ -337,6 +339,12 @@ static void sn65dsi83_atomic_enable(struct drm_bridge *bridge,
 	u16 val;
 	int ret;
 
+	ret = regulator_enable(ctx->vcc);
+	if (ret) {
+		dev_err(ctx->dev, "Failed to enable vcc: %d\n", ret);
+		return;
+	}
+
 	/* Deassert reset */
 	gpiod_set_value(ctx->enable_gpio, 1);
 	usleep_range(1000, 1100);
@@ -486,11 +494,16 @@ static void sn65dsi83_atomic_disable(struct drm_bridge *bridge,
 				     struct drm_bridge_state *old_bridge_state)
 {
 	struct sn65dsi83 *ctx = bridge_to_sn65dsi83(bridge);
+	int ret;
 
 	/* Put the chip in reset, pull EN line low, and assure 10ms reset low timing. */
 	gpiod_set_value(ctx->enable_gpio, 0);
 	usleep_range(10000, 11000);
 
+	ret = regulator_disable(ctx->vcc);
+	if (ret)
+		dev_err(ctx->dev, "Failed to disable vcc: %d\n", ret);
+
 	regcache_mark_dirty(ctx->regmap);
 }
 
@@ -599,6 +612,11 @@ static int sn65dsi83_parse_dt(struct sn65dsi83 *ctx, enum sn65dsi83_model model)
 
 	ctx->panel_bridge = panel_bridge;
 
+	ctx->vcc = devm_regulator_get(dev, "vcc");
+	if (IS_ERR(ctx->vcc))
+		return dev_err_probe(dev, PTR_ERR(ctx->vcc),
+				     "Failed to get supply 'vcc'\n");
+
 	return 0;
 }