2 files changed, 45 insertions, 38 deletions

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
index b022dd6e6b6e..a57ca8c3bdae 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
@@ -670,13 +670,28 @@ cdns_dsi_bridge_mode_valid(struct drm_bridge *bridge,
 	return MODE_OK;
 }
 
-static void cdns_dsi_bridge_atomic_disable(struct drm_bridge *bridge,
-					   struct drm_atomic_state *state)
+static void cdns_dsi_bridge_atomic_post_disable(struct drm_bridge *bridge,
+						struct drm_atomic_state *state)
 {
 	struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
 	struct cdns_dsi *dsi = input_to_dsi(input);
 	u32 val;
 
+	/*
+	 * The cdns-dsi controller needs to be disabled after it's DPI source
+	 * has stopped streaming. If this is not followed, there is a brief
+	 * window before DPI source is disabled and after cdns-dsi controller
+	 * has been disabled where the DPI stream is still on, but the cdns-dsi
+	 * controller is not ready anymore to accept the incoming signals. This
+	 * is one of the reasons why a shift in pixel colors is observed on
+	 * displays that have cdns-dsi as one of the bridges.
+	 *
+	 * To mitigate this, disable this bridge from the bridge post_disable()
+	 * hook, instead of the bridge _disable() hook. The bridge post_disable()
+	 * hook gets called after the CRTC disable, where often many DPI sources
+	 * disable their streams.
+	 */
+
 	val = readl(dsi->regs + MCTL_MAIN_DATA_CTL);
 	val &= ~(IF_VID_SELECT_MASK | IF_VID_MODE | VID_EN | HOST_EOT_GEN |
 		 DISP_EOT_GEN);
@@ -688,15 +703,6 @@ static void cdns_dsi_bridge_atomic_disable(struct drm_bridge *bridge,
 	if (dsi->platform_ops && dsi->platform_ops->disable)
 		dsi->platform_ops->disable(dsi);
 
-	pm_runtime_put(dsi->base.dev);
-}
-
-static void cdns_dsi_bridge_atomic_post_disable(struct drm_bridge *bridge,
-						struct drm_atomic_state *state)
-{
-	struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
-	struct cdns_dsi *dsi = input_to_dsi(input);
-
 	dsi->phy_initialized = false;
 	dsi->link_initialized = false;
 	phy_power_off(dsi->dphy);
@@ -774,8 +780,8 @@ static void cdns_dsi_init_link(struct cdns_dsi *dsi)
 	dsi->link_initialized = true;
 }
 
-static void cdns_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
-					  struct drm_atomic_state *state)
+static void cdns_dsi_bridge_atomic_pre_enable(struct drm_bridge *bridge,
+					      struct drm_atomic_state *state)
 {
 	struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
 	struct cdns_dsi *dsi = input_to_dsi(input);
@@ -792,6 +798,21 @@ static void cdns_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
 	u32 tmp, reg_wakeup, div, status;
 	int nlanes;
 
+	/*
+	 * The cdns-dsi controller needs to be enabled before it's DPI source
+	 * has begun streaming. If this is not followed, there is a brief window
+	 * after DPI source enable and before cdns-dsi controller enable where
+	 * the DPI stream is on, but the cdns-dsi controller is not ready to
+	 * accept the incoming signals. This is one of the reasons why a shift
+	 * in pixel colors is observed on displays that have cdns-dsi as one of
+	 * the bridges.
+	 *
+	 * To mitigate this, enable this bridge from the bridge pre_enable()
+	 * hook, instead of the bridge _enable() hook. The bridge pre_enable()
+	 * hook gets called before the CRTC enable, where often many DPI sources
+	 * enable their streams.
+	 */
+
 	if (WARN_ON(pm_runtime_get_sync(dsi->base.dev) < 0))
 		return;
 
@@ -811,8 +832,8 @@ static void cdns_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
 	mode = &crtc_state->adjusted_mode;
 	nlanes = output->dev->lanes;
 
-	cdns_dsi_hs_init(dsi);
 	cdns_dsi_init_link(dsi);
+	cdns_dsi_hs_init(dsi);
 
 	/*
 	 * Now that the DSI Link and DSI Phy are initialized,
@@ -941,19 +962,6 @@ static void cdns_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
 	writel(tmp, dsi->regs + MCTL_MAIN_EN);
 }
 
-static void cdns_dsi_bridge_atomic_pre_enable(struct drm_bridge *bridge,
-					      struct drm_atomic_state *state)
-{
-	struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
-	struct cdns_dsi *dsi = input_to_dsi(input);
-
-	if (WARN_ON(pm_runtime_get_sync(dsi->base.dev) < 0))
-		return;
-
-	cdns_dsi_init_link(dsi);
-	cdns_dsi_hs_init(dsi);
-}
-
 static u32 *cdns_dsi_bridge_get_input_bus_fmts(struct drm_bridge *bridge,
 					       struct drm_bridge_state *bridge_state,
 					       struct drm_crtc_state *crtc_state,
@@ -1048,9 +1056,7 @@ cdns_dsi_bridge_atomic_reset(struct drm_bridge *bridge)
 static const struct drm_bridge_funcs cdns_dsi_bridge_funcs = {
 	.attach = cdns_dsi_bridge_attach,
 	.mode_valid = cdns_dsi_bridge_mode_valid,
-	.atomic_disable = cdns_dsi_bridge_atomic_disable,
 	.atomic_pre_enable = cdns_dsi_bridge_atomic_pre_enable,
-	.atomic_enable = cdns_dsi_bridge_atomic_enable,
 	.atomic_post_disable = cdns_dsi_bridge_atomic_post_disable,
 	.atomic_check = cdns_dsi_bridge_atomic_check,
 	.atomic_reset = cdns_dsi_bridge_atomic_reset,
@@ -1289,9 +1295,10 @@ static int cdns_dsi_drm_probe(struct platform_device *pdev)
 	int ret, irq;
 	u32 val;
 
-	dsi = devm_kzalloc(&pdev->dev, sizeof(*dsi), GFP_KERNEL);
-	if (!dsi)
-		return -ENOMEM;
+	dsi = devm_drm_bridge_alloc(&pdev->dev, struct cdns_dsi, input.bridge,
+				    &cdns_dsi_bridge_funcs);
+	if (IS_ERR(dsi))
+		return PTR_ERR(dsi);
 
 	platform_set_drvdata(pdev, dsi);
 
@@ -1349,7 +1356,6 @@ static int cdns_dsi_drm_probe(struct platform_device *pdev)
 	 * CDNS_DPI_INPUT.
 	 */
 	input->id = CDNS_DPI_INPUT;
-	input->bridge.funcs = &cdns_dsi_bridge_funcs;
 	input->bridge.of_node = pdev->dev.of_node;
 
 	/* Mask all interrupts before registering the IRQ handler. */
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index b431e7efd1f0..a614d1384f71 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -2143,7 +2143,8 @@ static int cdns_mhdp_atomic_check(struct drm_bridge *bridge,
 	return 0;
 }
 
-static enum drm_connector_status cdns_mhdp_bridge_detect(struct drm_bridge *bridge)
+static enum drm_connector_status
+cdns_mhdp_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)
 {
 	struct cdns_mhdp_device *mhdp = bridge_to_mhdp(bridge);
 
@@ -2389,9 +2390,10 @@ static int cdns_mhdp_probe(struct platform_device *pdev)
 	int ret;
 	int irq;
 
-	mhdp = devm_kzalloc(dev, sizeof(*mhdp), GFP_KERNEL);
-	if (!mhdp)
-		return -ENOMEM;
+	mhdp = devm_drm_bridge_alloc(dev, struct cdns_mhdp_device, bridge,
+				     &cdns_mhdp_bridge_funcs);
+	if (IS_ERR(mhdp))
+		return PTR_ERR(mhdp);
 
 	clk = devm_clk_get_enabled(dev, NULL);
 	if (IS_ERR(clk)) {
@@ -2481,7 +2483,6 @@ static int cdns_mhdp_probe(struct platform_device *pdev)
 	mhdp->display_fmt.bpc = 8;
 
 	mhdp->bridge.of_node = pdev->dev.of_node;
-	mhdp->bridge.funcs = &cdns_mhdp_bridge_funcs;
 	mhdp->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID |
 			   DRM_BRIDGE_OP_HPD;
 	mhdp->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;