drm/omap: dss: Extend omapdss_of_find_source_for_first_ep() to sinks

The omapdss_of_find_source_for_first_ep() function locates the source
corresponding to the first endpoint of the first port of a device node.
We can easily extend it to locate sinks as well by passing the port
number as a parameter. This will be useful to find sinks in encoders
drivers.

Extend the function and rename it to omapdss_of_find_connected_device()
to reflect its new extended purpose.

Additionally, it is useful to differentiate between failures to return
the connected device because no link exists in the device tree for the
requested port, or because the connected device as described in the
device tree is invalid or not probed yet. Return NULL in the first case
and an error code in the second case, and update the callers
accordingly.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/displays/connector-analog-tv.c

@@ -47,10 +47,10 @@ static int tvc_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(ddata->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(ddata->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(ddata->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/connector-dvi.c

@@ -61,10 +61,10 @@ static int dvic_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/connector-hdmi.c

@@ -57,10 +57,10 @@ static int hdmic_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(ddata->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(ddata->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(ddata->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/encoder-opa362.c

@@ -37,7 +37,7 @@ static int opa362_connect(struct omap_dss_device *dssdev,
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
 	if (IS_ERR(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
 		return PTR_ERR(src);

drivers/gpu/drm/omapdrm/displays/encoder-tfp410.c

@@ -33,7 +33,7 @@ static int tfp410_connect(struct omap_dss_device *dssdev,
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
 	if (IS_ERR(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
 		return PTR_ERR(src);

drivers/gpu/drm/omapdrm/displays/encoder-tpd12s015.c

@@ -42,7 +42,7 @@ static int tpd_connect(struct omap_dss_device *dssdev,
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
 	if (IS_ERR(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
 		return PTR_ERR(src);

drivers/gpu/drm/omapdrm/displays/panel-dpi.c

@@ -39,10 +39,10 @@ static int panel_dpi_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c

@@ -763,10 +763,10 @@ static int dsicm_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/panel-lgphilips-lb035q02.c

@@ -121,10 +121,10 @@ static int lb035q02_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/panel-nec-nl8048hl11.c

@@ -116,10 +116,10 @@ static int nec_8048_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/panel-sharp-ls037v7dw01.c

@@ -62,10 +62,10 @@ static int sharp_ls_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/panel-sony-acx565akm.c

@@ -511,10 +511,10 @@ static int acx565akm_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c

@@ -170,10 +170,10 @@ static int td028ttec1_panel_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/displays/panel-tpo-td043mtea1.c

@@ -341,10 +341,10 @@ static int tpo_td043_connect(struct omap_dss_device *dssdev)
 	struct omap_dss_device *src;
 	int r;
 
-	src = omapdss_of_find_source_for_first_ep(dssdev->dev->of_node);
-	if (IS_ERR(src)) {
+	src = omapdss_of_find_connected_device(dssdev->dev->of_node, 0);
+	if (IS_ERR_OR_NULL(src)) {
 		dev_err(dssdev->dev, "failed to find video source\n");
-		return PTR_ERR(src);
+		return src ? PTR_ERR(src) : -EINVAL;
 	}
 
 	r = omapdss_device_connect(dssdev->dss, src, dssdev);

drivers/gpu/drm/omapdrm/dss/dss-of.c

@@ -47,7 +47,7 @@ dss_of_port_get_parent_device(struct device_node *port)
 }
 
 struct omap_dss_device *
-omapdss_of_find_source_for_first_ep(struct device_node *node)
+omapdss_of_find_connected_device(struct device_node *node, unsigned int port)
 {
 	struct device_node *src_node;
 	struct device_node *src_port;
@@ -56,27 +56,27 @@ omapdss_of_find_source_for_first_ep(struct device_node *node)
 	u32 port_number = 0;
 
 	/* Get the endpoint... */
-	ep = of_graph_get_endpoint_by_regs(node, 0, 0);
+	ep = of_graph_get_endpoint_by_regs(node, port, 0);
 	if (!ep)
-		return ERR_PTR(-EINVAL);
+		return NULL;
 
 	/* ... and its remote port... */
 	src_port = of_graph_get_remote_port(ep);
 	of_node_put(ep);
 	if (!src_port)
-		return ERR_PTR(-EINVAL);
+		return NULL;
 
 	/* ... and the remote port's number and parent... */
 	of_property_read_u32(src_port, "reg", &port_number);
 	src_node = dss_of_port_get_parent_device(src_port);
 	of_node_put(src_port);
 	if (!src_node)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
-	/* ... and finally the source. */
+	/* ... and finally the connected device. */
 	src = omapdss_find_device_by_port(src_node, port_number);
 	of_node_put(src_node);
 
 	return src ? src : ERR_PTR(-EPROBE_DEFER);
 }
-EXPORT_SYMBOL_GPL(omapdss_of_find_source_for_first_ep);
+EXPORT_SYMBOL_GPL(omapdss_of_find_connected_device);

drivers/gpu/drm/omapdrm/dss/omapdss.h

@@ -532,7 +532,7 @@ static inline bool omapdss_device_is_enabled(struct omap_dss_device *dssdev)
 }
 
 struct omap_dss_device *
-omapdss_of_find_source_for_first_ep(struct device_node *node);
+omapdss_of_find_connected_device(struct device_node *node, unsigned int port);
 
 enum dss_writeback_channel {
 	DSS_WB_LCD1_MGR =	0,