drm: convert drivers to use of_graph_get_remote_node

Convert drivers to use the new of_graph_get_remote_node() helper
instead of parsing the endpoint node and then getting the remote device
node. Now drivers can just specify the device node and which
port/endpoint and get back the connected remote device node. The details
of the graph binding are nicely abstracted into the core OF graph code.

This changes some error messages to debug messages (in the graph core).
Graph connections are often "no connects" depending on the particular
board, so we want to avoid spurious messages. Plus the kernel is not a
DT validator.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Liviu Dudau <liviu.dudau@arm.com>
Tested-by: Eric Anholt <eric@anholt.net>
Tested-by: Jyri Sarha <jsarha@ti.com>
Tested by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>

3 files changed, 5 insertions, 49 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dpi.c b/drivers/gpu/drm/exynos/exynos_drm_dpi.c
index 3aab71a485ba..63abcd280fa0 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dpi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dpi.c
@@ -163,27 +163,13 @@ enum {
 	FIMD_PORT_WRB,
 };
 
-static struct device_node *exynos_dpi_of_find_panel_node(struct device *dev)
-{
-	struct device_node *np, *ep;
-
-	ep = of_graph_get_endpoint_by_regs(dev->of_node, FIMD_PORT_RGB, 0);
-	if (!ep)
-		return NULL;
-
-	np = of_graph_get_remote_port_parent(ep);
-	of_node_put(ep);
-
-	return np;
-}
-
 static int exynos_dpi_parse_dt(struct exynos_dpi *ctx)
 {
 	struct device *dev = ctx->dev;
 	struct device_node *dn = dev->of_node;
 	struct device_node *np;
 
-	ctx->panel_node = exynos_dpi_of_find_panel_node(dev);
+	ctx->panel_node = of_graph_get_remote_node(dn, FIMD_PORT_RGB, 0);
 
 	np = of_get_child_by_name(dn, "display-timings");
 	if (np) {
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index 6d4da2f0932d..fc4fda738906 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -1659,17 +1659,10 @@ static int exynos_dsi_parse_dt(struct exynos_dsi *dsi)
 
 	of_node_put(ep);
 
-	ep = of_graph_get_next_endpoint(node, NULL);
-	if (!ep) {
-		ret = -EINVAL;
-		goto end;
-	}
+	dsi->bridge_node = of_graph_get_remote_node(node, DSI_PORT_OUT, 0);
+	if (!dsi->bridge_node)
+		return -EINVAL;
 
-	dsi->bridge_node = of_graph_get_remote_port_parent(ep);
-	if (!dsi->bridge_node) {
-		ret = -EINVAL;
-		goto end;
-	}
 end:
 	of_node_put(ep);
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_mic.c b/drivers/gpu/drm/exynos/exynos_drm_mic.c
index 2ef43d403eaa..e45720543a45 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_mic.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_mic.c
@@ -229,29 +229,6 @@ static void mic_set_reg_on(struct exynos_mic *mic, bool enable)
 	writel(reg, mic->reg + MIC_OP);
 }
 
-static struct device_node *get_remote_node(struct device_node *from, int reg)
-{
-	struct device_node *endpoint = NULL, *remote_node = NULL;
-
-	endpoint = of_graph_get_endpoint_by_regs(from, reg, -1);
-	if (!endpoint) {
-		DRM_ERROR("mic: Failed to find remote port from %s",
-				from->full_name);
-		goto exit;
-	}
-
-	remote_node = of_graph_get_remote_port_parent(endpoint);
-	if (!remote_node) {
-		DRM_ERROR("mic: Failed to find remote port parent from %s",
-							from->full_name);
-		goto exit;
-	}
-
-exit:
-	of_node_put(endpoint);
-	return remote_node;
-}
-
 static int parse_dt(struct exynos_mic *mic)
 {
 	int ret = 0, i, j;
@@ -263,7 +240,7 @@ static int parse_dt(struct exynos_mic *mic)
 	 * The first node must be for decon and the second one must be for dsi.
 	 */
 	for (i = 0, j = 0; i < NUM_ENDPOINTS; i++) {
-		remote_node = get_remote_node(mic->dev->of_node, i);
+		remote_node = of_graph_get_remote_node(mic->dev->of_node, i, 0);
 		if (!remote_node) {
 			ret = -EPIPE;
 			goto exit;