[PATCH 31/36] drm: xlnx: zynqmp_dpsub: Parse DT to find connected ports

[Laurent Pinchart]

To prepare for live video input support, parse the device tree to find
the connected ports. Warn about unsupported configurations, and error
out when invalid.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 drivers/gpu/drm/xlnx/zynqmp_dpsub.c | 54 +++++++++++++++++++++++++++++
 drivers/gpu/drm/xlnx/zynqmp_dpsub.h | 13 +++++++
 2 files changed, 67 insertions(+)

diff --git a/drivers/gpu/drm/xlnx/zynqmp_dpsub.c b/drivers/gpu/drm/xlnx/zynqmp_dpsub.c
index e6532a13fb78..bc2b3ab3001d 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dpsub.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dpsub.c
@@ -12,6 +12,7 @@
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
 #include <linux/module.h>
+#include <linux/of_graph.h>
 #include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
@@ -141,6 +142,55 @@ static int zynqmp_dpsub_init_clocks(struct zynqmp_dpsub *dpsub)
 	return 0;
 }
 
+static int zynqmp_dpsub_parse_dt(struct zynqmp_dpsub *dpsub)
+{
+	struct device_node *np;
+	unsigned int i;
+
+	/*
+	 * For backward compatibility with old device trees that don't contain
+	 * ports, consider that only the DP output port is connected if no
+	 * ports child no exists.
+	 */
+	np = of_get_child_by_name(dpsub->dev->of_node, "ports");
+	of_node_put(np);
+	if (!np) {
+		dev_warn(dpsub->dev, "missing ports, update DT bindings\n");
+		dpsub->connected_ports = BIT(ZYNQMP_DPSUB_PORT_OUT_DP);
+		return 0;
+	}
+
+	/* Check which ports are connected. */
+	for (i = 0; i < ZYNQMP_DPSUB_NUM_PORTS; ++i) {
+		struct device_node *np;
+
+		np = of_graph_get_remote_node(dpsub->dev->of_node, i, -1);
+		if (np) {
+			dpsub->connected_ports |= BIT(i);
+			of_node_put(np);
+		}
+	}
+
+	/* Sanity checks. */
+	if ((dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_VIDEO)) ||
+	    (dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_GFX)))
+		dev_warn(dpsub->dev, "live video unsupported, ignoring\n");
+
+	if (dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_AUDIO))
+		dev_warn(dpsub->dev, "live audio unsupported, ignoring\n");
+
+	if ((dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_OUT_VIDEO)) ||
+	    (dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_OUT_AUDIO)))
+		dev_warn(dpsub->dev, "output to PL unsupported, ignoring\n");
+
+	if (!(dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_OUT_DP))) {
+		dev_err(dpsub->dev, "DP output port not connected\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 void zynqmp_dpsub_release(struct zynqmp_dpsub *dpsub)
 {
 	kfree(dpsub->disp);
@@ -170,6 +220,10 @@ static int zynqmp_dpsub_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto err_mem;
 
+	ret = zynqmp_dpsub_parse_dt(dpsub);
+	if (ret < 0)
+		goto err_mem;
+
 	pm_runtime_enable(&pdev->dev);
 
 	/*
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dpsub.h b/drivers/gpu/drm/xlnx/zynqmp_dpsub.h
index 6c6029ad9bc5..6ded6e45ac0a 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dpsub.h
+++ b/drivers/gpu/drm/xlnx/zynqmp_dpsub.h
@@ -22,6 +22,16 @@ struct zynqmp_dpsub_drm;
 
 #define ZYNQMP_DPSUB_NUM_LAYERS				2
 
+enum zynqmp_dpsub_port {
+	ZYNQMP_DPSUB_PORT_LIVE_VIDEO,
+	ZYNQMP_DPSUB_PORT_LIVE_GFX,
+	ZYNQMP_DPSUB_PORT_LIVE_AUDIO,
+	ZYNQMP_DPSUB_PORT_OUT_VIDEO,
+	ZYNQMP_DPSUB_PORT_OUT_AUDIO,
+	ZYNQMP_DPSUB_PORT_OUT_DP,
+	ZYNQMP_DPSUB_NUM_PORTS,
+};
+
 enum zynqmp_dpsub_format {
 	ZYNQMP_DPSUB_FORMAT_RGB,
 	ZYNQMP_DPSUB_FORMAT_YCRCB444,
@@ -37,6 +47,7 @@ enum zynqmp_dpsub_format {
  * @vid_clk_from_ps: True of the video clock comes from PS, false from PL
  * @aud_clk: Audio clock
  * @aud_clk_from_ps: True of the audio clock comes from PS, false from PL
+ * @connected_ports: Bitmask of connected ports in the device tree
  * @drm: The DRM/KMS device data
  * @bridge: The DP encoder bridge
  * @disp: The display controller
@@ -52,6 +63,8 @@ struct zynqmp_dpsub {
 	struct clk *aud_clk;
 	bool aud_clk_from_ps;
 
+	unsigned int connected_ports;
+
 	struct zynqmp_dpsub_drm *drm;
 	struct drm_bridge *bridge;
 
-- 
Regards,

Laurent Pinchart