[PATCH] drm: rockchip: Don't require MIPI DSI device when it's used for ISP

[Ondřej Jirman]

From: Ondrej Jirman <megi at xff.cz>

On RK3399 one MIPI DSI device can be alternatively used with the ISP1,
to provide RX DPHY. When this is the case (ISP1 is enabled in device
tree), probe success of DRM is tied to probe success of ISP1 connected
camera sensor. This can fail if the user is able to killswitch the camera
power, like on Pinephone Pro.

Detect use of MIPI DSI controller by ISP, and don't include it in
component match list in that case.

Signed-off-by: Ondrej Jirman <megi at xff.cz>
---
 drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 47 +++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
index ab55d7132550..f47de94ad576 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
@@ -354,6 +354,43 @@ static void rockchip_drm_match_remove(struct device *dev)
 		device_link_del(link);
 }
 
+/*
+ * Check if ISP block linked to a mipi-dsi device via phys phandle is
+ * enabled in device tree.
+ */
+static bool rockchip_drm_is_mipi1_and_used_by_isp(struct device *dev)
+{
+	struct device_node *np = NULL, *phy_np;
+
+	if (!of_device_is_compatible(dev->of_node, "rockchip,rk3399-mipi-dsi"))
+		return false;
+
+	while (true) {
+		np = of_find_compatible_node(np, NULL, "rockchip,rk3399-cif-isp");
+		if (!np)
+			break;
+
+		if (!of_device_is_available(np)) {
+			of_node_put(np);
+			continue;
+		}
+
+		phy_np = of_parse_phandle(np, "phys", 0);
+		if (!phy_np) {
+			of_node_put(np);
+			continue;
+		}
+
+		of_node_put(phy_np);
+		of_node_put(np);
+
+		if (phy_np == dev->of_node)
+			return true;
+	}
+
+	return false;
+}
+
 static struct component_match *rockchip_drm_match_add(struct device *dev)
 {
 	struct component_match *match = NULL;
@@ -371,6 +408,16 @@ static struct component_match *rockchip_drm_match_add(struct device *dev)
 			if (!d)
 				break;
 
+			/*
+			 * If mipi1 is connected to ISP, we don't want to wait for mipi1 component,
+			 * because it will not be used by DRM anyway, to not tie success of camera
+			 * driver probe to display pipeline initialization.
+			 */
+			if (rockchip_drm_is_mipi1_and_used_by_isp(d)) {
+				dev_info(d, "used by ISP1, skipping from DRM\n");
+				continue;
+			}
+
 			device_link_add(dev, d, DL_FLAG_STATELESS);
 			component_match_add(dev, &match, component_compare_dev, d);
 		} while (true);
-- 
2.43.0