drm/vc4: hdmi: Add reset callback

The BCM2711 and BCM283x HDMI controllers use a slightly different reset
sequence, so let's add a callback to reset the controller.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/a34bcb493da07eae58ed704f65e72ce0748e8952.1599120059.git-series.maxime@cerno.tech

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -69,6 +69,21 @@ static int vc4_hdmi_debugfs_regs(struct seq_file *m, void *unused)
 	return 0;
 }
 
+static void vc4_hdmi_reset(struct vc4_hdmi *vc4_hdmi)
+{
+	HDMI_WRITE(HDMI_M_CTL, VC4_HD_M_SW_RST);
+	udelay(1);
+	HDMI_WRITE(HDMI_M_CTL, 0);
+
+	HDMI_WRITE(HDMI_M_CTL, VC4_HD_M_ENABLE);
+
+	HDMI_WRITE(HDMI_SW_RESET_CONTROL,
+		   VC4_HDMI_SW_RESET_HDMI |
+		   VC4_HDMI_SW_RESET_FORMAT_DETECT);
+
+	HDMI_WRITE(HDMI_SW_RESET_CONTROL, 0);
+}
+
 static enum drm_connector_status
 vc4_hdmi_connector_detect(struct drm_connector *connector, bool force)
 {
@@ -363,11 +378,8 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder)
 		return;
 	}
 
-	HDMI_WRITE(HDMI_SW_RESET_CONTROL,
-		   VC4_HDMI_SW_RESET_HDMI |
-		   VC4_HDMI_SW_RESET_FORMAT_DETECT);
-
-	HDMI_WRITE(HDMI_SW_RESET_CONTROL, 0);
+	if (vc4_hdmi->variant->reset)
+		vc4_hdmi->variant->reset(vc4_hdmi);
 
 	/* PHY should be in reset, like
 	 * vc4_hdmi_encoder_disable() does.
@@ -1291,14 +1303,6 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 		vc4_hdmi->hpd_active_low = hpd_gpio_flags & OF_GPIO_ACTIVE_LOW;
 	}
 
-	/* HDMI core must be enabled. */
-	if (!(HDMI_READ(HDMI_M_CTL) & VC4_HD_M_ENABLE)) {
-		HDMI_WRITE(HDMI_M_CTL, VC4_HD_M_SW_RST);
-		udelay(1);
-		HDMI_WRITE(HDMI_M_CTL, 0);
-
-		HDMI_WRITE(HDMI_M_CTL, VC4_HD_M_ENABLE);
-	}
 	pm_runtime_enable(dev);
 
 	drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_TMDS);
@@ -1427,6 +1431,7 @@ static const struct vc4_hdmi_variant bcm2835_variant = {
 	.num_registers		= ARRAY_SIZE(vc4_hdmi_fields),
 
 	.init_resources		= vc4_hdmi_init_resources,
+	.reset			= vc4_hdmi_reset,
 };
 
 static const struct of_device_id vc4_hdmi_dt_match[] = {

drivers/gpu/drm/vc4/vc4_hdmi.h

@@ -35,6 +35,9 @@ struct vc4_hdmi_variant {
 	 * clocks, etc) for that variant.
 	 */
 	int (*init_resources)(struct vc4_hdmi *vc4_hdmi);
+
+	/* Callback to reset the HDMI block */
+	void (*reset)(struct vc4_hdmi *vc4_hdmi);
 };
 
 /* HDMI audio information */