[PATCH v4 4/7] drm/rcar-du: dsi: Support DSC in the pipeline

[Tomi Valkeinen]

Enabling DSI clocks on rcar-du needs some tricks as the DU dot clock is
provided by the DSI. Thus, we call rcar_mipi_dsi_pclk_enable() from the
crtc, when enabling the crtc.

With DSC (added in upcoming patch) in the pipeline, between the DU and
the DSI, the above call path is broken as the crtc tries to call
rcar_mipi_dsi_pclk_enable() on the DSC.

To solve this problem, add checks to rcar_du_crtc_atomic_enable() and
rcar_du_crtc_atomic_disable() to detect the DSC via the bridge type, and
skip the DCS bridge when needed.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/renesas/rcar-du/rcar_du_crtc.c  | 18 ++++++++++++++++++
 drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c |  1 +
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/renesas/rcar-du/rcar_du_crtc.c
index 6c07c406f725..f14fd89f9104 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_crtc.c
@@ -754,6 +754,15 @@ static void rcar_du_crtc_atomic_enable(struct drm_crtc *crtc,
 	     (BIT(RCAR_DU_OUTPUT_DSI0) | BIT(RCAR_DU_OUTPUT_DSI1)))) {
 		struct drm_bridge *bridge = rcdu->dsi[rcrtc->index];
 
+		/*
+		 * When we have a DSC block between the DU and the DSI,
+		 * the "bridge" points to the DSC. Detect the DSC by looking
+		 * at the bridge type, and skip the DSC if the bridge is not
+		 * the DSI bridge.
+		 */
+		if (bridge->type != DRM_MODE_CONNECTOR_DSI)
+			bridge = bridge->next_bridge;
+
 		rcar_mipi_dsi_pclk_enable(bridge, state);
 	}
 
@@ -796,6 +805,15 @@ static void rcar_du_crtc_atomic_disable(struct drm_crtc *crtc,
 	     (BIT(RCAR_DU_OUTPUT_DSI0) | BIT(RCAR_DU_OUTPUT_DSI1)))) {
 		struct drm_bridge *bridge = rcdu->dsi[rcrtc->index];
 
+		/*
+		 * When we have a DSC block between the DU and the DSI,
+		 * the "bridge" points to the DSC. Detect the DSC by looking
+		 * at the bridge type, and skip the DSC if the bridge is not
+		 * the DSI bridge.
+		 */
+		if (bridge->type != DRM_MODE_CONNECTOR_DSI)
+			bridge = bridge->next_bridge;
+
 		/*
 		 * Disable the DSI clock output, see
 		 * rcar_du_crtc_atomic_enable().
diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
index aaafee1c060b..f429f03a380c 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
@@ -957,6 +957,7 @@ static int rcar_mipi_dsi_host_attach(struct mipi_dsi_host *host,
 
 	/* Initialize the DRM bridge. */
 	dsi->bridge.of_node = dsi->dev->of_node;
+	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
 	drm_bridge_add(&dsi->bridge);
 
 	return 0;

-- 
2.43.0