Re: [PATCH v2 4/6] drm: convert drivers to use of_graph_get_remote_node

[Archit Taneja]

On 02/10/2017 12:35 AM, Rob Herring wrote:
> 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.

For the msm and adv75xx driver:

Tested by: Archit Taneja <architt@xxxxxxxxxxxxxx>

> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
> Acked-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> Acked-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> Tested-by: Liviu Dudau <liviu.dudau@xxxxxxx>
> Tested-by: Eric Anholt <eric@xxxxxxxxxx>
> ---
> v2:
> - tilcdc fix (Jyri Sarha)
> - Dropped an incomplete meson change.
>
>  drivers/gpu/drm/arm/hdlcd_drv.c                 | 22 ++------
>  drivers/gpu/drm/arm/malidp_drv.c                | 28 ++--------
>  drivers/gpu/drm/bridge/adv7511/adv7533.c        | 12 +----
>  drivers/gpu/drm/bridge/dumb-vga-dac.c           | 15 ++----
>  drivers/gpu/drm/bridge/ti-tfp410.c              | 15 ++----
>  drivers/gpu/drm/exynos/exynos_drm_dpi.c         | 16 +-----
>  drivers/gpu/drm/exynos/exynos_drm_dsi.c         | 13 ++---
>  drivers/gpu/drm/exynos/exynos_drm_mic.c         | 27 +---------
>  drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 30 +----------
>  drivers/gpu/drm/mediatek/mtk_dpi.c              | 12 ++---
>  drivers/gpu/drm/mediatek/mtk_hdmi.c             | 26 ++--------
>  drivers/gpu/drm/meson/meson_venc_cvbs.c         | 19 ++-----
>  drivers/gpu/drm/msm/dsi/dsi_host.c              |  3 +-
>  drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c         | 28 +---------
>  drivers/gpu/drm/rockchip/rockchip_drm_drv.c     | 18 +++----
>  drivers/gpu/drm/tilcdc/tilcdc_crtc.c            | 12 +----
>  drivers/gpu/drm/tilcdc/tilcdc_external.c        | 68 +++----------------------
>  drivers/gpu/drm/vc4/vc4_dpi.c                   | 15 ++----
>  18 files changed, 55 insertions(+), 324 deletions(-)
>
> diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
> index e5f4f4a6546d..0f70f5fe9970 100644
> --- a/drivers/gpu/drm/arm/hdlcd_drv.c
> +++ b/drivers/gpu/drm/arm/hdlcd_drv.c
> @@ -430,29 +430,13 @@ static int compare_dev(struct device *dev, void *data)
>
>  static int hdlcd_probe(struct platform_device *pdev)
>  {
> -	struct device_node *port, *ep;
> +	struct device_node *port;
>  	struct component_match *match = NULL;
>
> -	if (!pdev->dev.of_node)
> -		return -ENODEV;
> -
>  	/* there is only one output port inside each device, find it */
> -	ep = of_graph_get_next_endpoint(pdev->dev.of_node, NULL);
> -	if (!ep)
> -		return -ENODEV;
> -
> -	if (!of_device_is_available(ep)) {
> -		of_node_put(ep);
> +	port = of_graph_get_remote_node(pdev->dev.of_node, 0, 0);
> +	if (!port)
>  		return -ENODEV;
> -	}
> -
> -	/* add the remote encoder port as component */
> -	port = of_graph_get_remote_port_parent(ep);
> -	of_node_put(ep);
> -	if (!port || !of_device_is_available(port)) {
> -		of_node_put(port);
> -		return -EAGAIN;
> -	}
>
>  	drm_of_component_match_add(&pdev->dev, &match, compare_dev, port);
>  	of_node_put(port);
> diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
> index 32f746e31379..47b552f1337c 100644
> --- a/drivers/gpu/drm/arm/malidp_drv.c
> +++ b/drivers/gpu/drm/arm/malidp_drv.c
> @@ -262,7 +262,6 @@ static int malidp_bind(struct device *dev)
>  {
>  	struct resource *res;
>  	struct drm_device *drm;
> -	struct device_node *ep;
>  	struct malidp_drm *malidp;
>  	struct malidp_hw_device *hwdev;
>  	struct platform_device *pdev = to_platform_device(dev);
> @@ -360,12 +359,7 @@ static int malidp_bind(struct device *dev)
>  		goto init_fail;
>
>  	/* Set the CRTC's port so that the encoder component can find it */
> -	ep = of_graph_get_next_endpoint(dev->of_node, NULL);
> -	if (!ep) {
> -		ret = -EINVAL;
> -		goto port_fail;
> -	}
> -	malidp->crtc.port = of_get_next_parent(ep);
> +	malidp->crtc.port = of_graph_get_port_by_id(dev->of_node, 0);
>
>  	ret = component_bind_all(dev, drm);
>  	if (ret) {
> @@ -420,7 +414,6 @@ static int malidp_bind(struct device *dev)
>  bind_fail:
>  	of_node_put(malidp->crtc.port);
>  	malidp->crtc.port = NULL;
> -port_fail:
>  	malidp_fini(drm);
>  init_fail:
>  	drm->dev_private = NULL;
> @@ -478,29 +471,16 @@ static int malidp_compare_dev(struct device *dev, void *data)
>
>  static int malidp_platform_probe(struct platform_device *pdev)
>  {
> -	struct device_node *port, *ep;
> +	struct device_node *port;
>  	struct component_match *match = NULL;
>
>  	if (!pdev->dev.of_node)
>  		return -ENODEV;
>
>  	/* there is only one output port inside each device, find it */
> -	ep = of_graph_get_next_endpoint(pdev->dev.of_node, NULL);
> -	if (!ep)
> -		return -ENODEV;
> -
> -	if (!of_device_is_available(ep)) {
> -		of_node_put(ep);
> +	port = of_graph_get_remote_node(pdev->dev.of_node, 0, 0);
> +	if (!port)
>  		return -ENODEV;
> -	}
> -
> -	/* add the remote encoder port as component */
> -	port = of_graph_get_remote_port_parent(ep);
> -	of_node_put(ep);
> -	if (!port || !of_device_is_available(port)) {
> -		of_node_put(port);
> -		return -EAGAIN;
> -	}
>
>  	drm_of_component_match_add(&pdev->dev, &match, malidp_compare_dev,
>  				   port);
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7533.c b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> index 8b210373cfa2..ac804f81e2f6 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7533.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> @@ -232,7 +232,6 @@ void adv7533_detach_dsi(struct adv7511 *adv)
>  int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
>  {
>  	u32 num_lanes;
> -	struct device_node *endpoint;
>
>  	of_property_read_u32(np, "adi,dsi-lanes", &num_lanes);
>
> @@ -241,17 +240,10 @@ int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
>
>  	adv->num_dsi_lanes = num_lanes;
>
> -	endpoint = of_graph_get_next_endpoint(np, NULL);
> -	if (!endpoint)
> +	adv->host_node = of_graph_get_remote_node(np, 0, 0);
> +	if (!adv->host_node)
>  		return -ENODEV;
>
> -	adv->host_node = of_graph_get_remote_port_parent(endpoint);
> -	if (!adv->host_node) {
> -		of_node_put(endpoint);
> -		return -ENODEV;
> -	}
> -
> -	of_node_put(endpoint);
>  	of_node_put(adv->host_node);
>
>  	adv->use_timing_gen = !of_property_read_bool(np,
> diff --git a/drivers/gpu/drm/bridge/dumb-vga-dac.c b/drivers/gpu/drm/bridge/dumb-vga-dac.c
> index e5706981c934..47b4c99162ad 100644
> --- a/drivers/gpu/drm/bridge/dumb-vga-dac.c
> +++ b/drivers/gpu/drm/bridge/dumb-vga-dac.c
> @@ -154,21 +154,12 @@ static const struct drm_bridge_funcs dumb_vga_bridge_funcs = {
>
>  static struct i2c_adapter *dumb_vga_retrieve_ddc(struct device *dev)
>  {
> -	struct device_node *end_node, *phandle, *remote;
> +	struct device_node *phandle, *remote;
>  	struct i2c_adapter *ddc;
>
> -	end_node = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1);
> -	if (!end_node) {
> -		dev_err(dev, "Missing connector endpoint\n");
> -		return ERR_PTR(-ENODEV);
> -	}
> -
> -	remote = of_graph_get_remote_port_parent(end_node);
> -	of_node_put(end_node);
> -	if (!remote) {
> -		dev_err(dev, "Enable to parse remote node\n");
> +	remote = of_graph_get_remote_node(dev->of_node, 1, -1);
> +	if (!remote)
>  		return ERR_PTR(-EINVAL);
> -	}
>
>  	phandle = of_parse_phandle(remote, "ddc-i2c-bus", 0);
>  	of_node_put(remote);
> diff --git a/drivers/gpu/drm/bridge/ti-tfp410.c b/drivers/gpu/drm/bridge/ti-tfp410.c
> index b054ea349952..82a6bdbf6ad0 100644
> --- a/drivers/gpu/drm/bridge/ti-tfp410.c
> +++ b/drivers/gpu/drm/bridge/ti-tfp410.c
> @@ -127,18 +127,13 @@ static const struct drm_bridge_funcs tfp410_bridge_funcs = {
>
>  static int tfp410_get_connector_ddc(struct tfp410 *dvi)
>  {
> -	struct device_node *ep = NULL, *connector_node = NULL;
> -	struct device_node *ddc_phandle = NULL;
> +	struct device_node *connector_node, *ddc_phandle;
>  	int ret = 0;
>
>  	/* port@1 is the connector node */
> -	ep = of_graph_get_endpoint_by_regs(dvi->dev->of_node, 1, -1);
> -	if (!ep)
> -		goto fail;
> -
> -	connector_node = of_graph_get_remote_port_parent(ep);
> +	connector_node = of_graph_get_remote_node(dvi->dev->of_node, 1, -1);
>  	if (!connector_node)
> -		goto fail;
> +		return -ENODEV;
>
>  	ddc_phandle = of_parse_phandle(connector_node, "ddc-i2c-bus", 0);
>  	if (!ddc_phandle)
> @@ -150,10 +145,10 @@ static int tfp410_get_connector_ddc(struct tfp410 *dvi)
>  	else
>  		ret = -EPROBE_DEFER;
>
> +	of_node_put(ddc_phandle);
> +
>  fail:
> -	of_node_put(ep);
>  	of_node_put(connector_node);
> -	of_node_put(ddc_phandle);
>  	return ret;
>  }
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dpi.c b/drivers/gpu/drm/exynos/exynos_drm_dpi.c
> index ad6b73c7fc59..eea529cea19a 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dpi.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dpi.c
> @@ -164,27 +164,13 @@ 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 e07cb1fe4860..04528f512c91 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> @@ -1670,17 +1670,10 @@ 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 a0def0be6d65..93ebb12133e1 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_mic.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_mic.c
> @@ -228,29 +228,6 @@ 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;
> @@ -262,7 +239,7 @@ 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;
> @@ -279,7 +256,7 @@ static int parse_dt(struct exynos_mic *mic)
>  			break;
>  		case ENDPOINT_DSI_NODE:
>  			/* panel node */
> -			remote_node = get_remote_node(remote_node, 1);
> +			remote_node = of_graph_get_remote_node(remote_node, 1, 0);
>  			if (!remote_node) {
>  				ret = -EPIPE;
>  				goto exit;
> diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
> index ebd5f4fe4c23..18d6570e057d 100644
> --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
> +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
> @@ -247,34 +247,6 @@ static const struct component_master_ops kirin_drm_ops = {
>  	.unbind = kirin_drm_unbind,
>  };
>
> -static struct device_node *kirin_get_remote_node(struct device_node *np)
> -{
> -	struct device_node *endpoint, *remote;
> -
> -	/* get the first endpoint, in our case only one remote node
> -	 * is connected to display controller.
> -	 */
> -	endpoint = of_graph_get_next_endpoint(np, NULL);
> -	if (!endpoint) {
> -		DRM_ERROR("no valid endpoint node\n");
> -		return ERR_PTR(-ENODEV);
> -	}
> -
> -	remote = of_graph_get_remote_port_parent(endpoint);
> -	of_node_put(endpoint);
> -	if (!remote) {
> -		DRM_ERROR("no valid remote node\n");
> -		return ERR_PTR(-ENODEV);
> -	}
> -
> -	if (!of_device_is_available(remote)) {
> -		DRM_ERROR("not available for remote node\n");
> -		return ERR_PTR(-ENODEV);
> -	}
> -
> -	return remote;
> -}
> -
>  static int kirin_drm_platform_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -288,7 +260,7 @@ static int kirin_drm_platform_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>
> -	remote = kirin_get_remote_node(np);
> +	remote = of_graph_get_remote_node(np, 0, 0);
>  	if (IS_ERR(remote))
>  		return PTR_ERR(remote);
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 90fb831ef031..dbd554c09a39 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -661,7 +661,7 @@ static int mtk_dpi_probe(struct platform_device *pdev)
>  	struct device *dev = &pdev->dev;
>  	struct mtk_dpi *dpi;
>  	struct resource *mem;
> -	struct device_node *ep, *bridge_node = NULL;
> +	struct device_node *bridge_node;
>  	int comp_id;
>  	int ret;
>
> @@ -706,15 +706,9 @@ static int mtk_dpi_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>
> -	ep = of_graph_get_next_endpoint(dev->of_node, NULL);
> -	if (ep) {
> -		bridge_node = of_graph_get_remote_port_parent(ep);
> -		of_node_put(ep);
> -	}
> -	if (!bridge_node) {
> -		dev_err(dev, "Failed to find bridge node\n");
> +	bridge_node = of_graph_get_remote_node(dev->of_node, 0, 0);
> +	if (!bridge_node)
>  		return -ENODEV;
> -	}
>
>  	dev_info(dev, "Found bridge node: %s\n", bridge_node->full_name);
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c
> index 0e8c4d9af340..f14e472812ce 100644
> --- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
> @@ -1433,7 +1433,7 @@ static int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi,
>  {
>  	struct device *dev = &pdev->dev;
>  	struct device_node *np = dev->of_node;
> -	struct device_node *cec_np, *port, *ep, *remote, *i2c_np;
> +	struct device_node *cec_np, *remote, *i2c_np;
>  	struct platform_device *cec_pdev;
>  	struct regmap *regmap;
>  	struct resource *mem;
> @@ -1485,29 +1485,9 @@ static int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi,
>  	if (IS_ERR(hdmi->regs))
>  		return PTR_ERR(hdmi->regs);
>
> -	port = of_graph_get_port_by_id(np, 1);
> -	if (!port) {
> -		dev_err(dev, "Missing output port node\n");
> +	remote = of_graph_get_remote_node(np, 1, 0);
> +	if (!remote)
>  		return -EINVAL;
> -	}
> -
> -	ep = of_get_child_by_name(port, "endpoint");
> -	if (!ep) {
> -		dev_err(dev, "Missing endpoint node in port %s\n",
> -			port->full_name);
> -		of_node_put(port);
> -		return -EINVAL;
> -	}
> -	of_node_put(port);
> -
> -	remote = of_graph_get_remote_port_parent(ep);
> -	if (!remote) {
> -		dev_err(dev, "Missing connector/bridge node for endpoint %s\n",
> -			ep->full_name);
> -		of_node_put(ep);
> -		return -EINVAL;
> -	}
> -	of_node_put(ep);
>
>  	if (!of_device_is_compatible(remote, "hdmi-connector")) {
>  		hdmi->bridge.next = of_drm_find_bridge(remote);
> diff --git a/drivers/gpu/drm/meson/meson_venc_cvbs.c b/drivers/gpu/drm/meson/meson_venc_cvbs.c
> index a2bcc70a03ef..8566de2edb62 100644
> --- a/drivers/gpu/drm/meson/meson_venc_cvbs.c
> +++ b/drivers/gpu/drm/meson/meson_venc_cvbs.c
> @@ -217,25 +217,14 @@ static const struct drm_encoder_helper_funcs
>
>  static bool meson_venc_cvbs_connector_is_available(struct meson_drm *priv)
>  {
> -	struct device_node *ep, *remote;
> +	struct device_node *remote;
>
> -	/* CVBS VDAC output is on the first port, first endpoint */
> -	ep = of_graph_get_endpoint_by_regs(priv->dev->of_node, 0, 0);
> -	if (!ep)
> +	remote = of_graph_get_remote_node(priv->dev->of_node, 0, 0);
> +	if (!remote)
>  		return false;
>
> -
> -	/* If the endpoint node exists, consider it enabled */
> -	remote = of_graph_get_remote_port(ep);
> -	if (remote) {
> -		of_node_put(ep);
> -		return true;
> -	}
> -
> -	of_node_put(ep);
>  	of_node_put(remote);
> -
> -	return false;
> +	return true;
>  }
>
>  int meson_venc_cvbs_create(struct meson_drm *priv)
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 3819fdefcae2..da8619f9eb2e 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -1637,9 +1637,8 @@ static int dsi_host_parse_dt(struct msm_dsi_host *msm_host)
>  	}
>
>  	/* Get panel node from the output port's endpoint data */
> -	device_node = of_graph_get_remote_port_parent(endpoint);
> +	device_node = of_graph_get_remote_node(np, 1, 0);
>  	if (!device_node) {
> -		dev_err(dev, "%s: no valid device\n", __func__);
>  		ret = -ENODEV;
>  		goto err;
>  	}
> diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c
> index b782efd4b95f..9f36fad1915e 100644
> --- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c
> +++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c
> @@ -225,32 +225,6 @@ int mdp4_enable(struct mdp4_kms *mdp4_kms)
>  	return 0;
>  }
>
> -static struct device_node *mdp4_detect_lcdc_panel(struct drm_device *dev)
> -{
> -	struct device_node *endpoint, *panel_node;
> -	struct device_node *np = dev->dev->of_node;
> -
> -	/*
> -	 * LVDS/LCDC is the first port described in the list of ports in the
> -	 * MDP4 DT node.
> -	 */
> -	endpoint = of_graph_get_endpoint_by_regs(np, 0, -1);
> -	if (!endpoint) {
> -		DBG("no LVDS remote endpoint\n");
> -		return NULL;
> -	}
> -
> -	panel_node = of_graph_get_remote_port_parent(endpoint);
> -	if (!panel_node) {
> -		DBG("no valid panel node in LVDS endpoint\n");
> -		of_node_put(endpoint);
> -		return NULL;
> -	}
> -
> -	of_node_put(endpoint);
> -
> -	return panel_node;
> -}
>
>  static int mdp4_modeset_init_intf(struct mdp4_kms *mdp4_kms,
>  				  int intf_type)
> @@ -270,7 +244,7 @@ static int mdp4_modeset_init_intf(struct mdp4_kms *mdp4_kms,
>  		 * bail out early if there is no panel node (no need to
>  		 * initialize LCDC encoder and LVDS connector)
>  		 */
> -		panel_node = mdp4_detect_lcdc_panel(dev);
> +		panel_node = of_graph_get_remote_node(dev->dev->of_node, 0, 0);
>  		if (!panel_node)
>  			return 0;
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
> index 2390c8577617..5e7ccd04ada6 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
> @@ -373,19 +373,13 @@ static void rockchip_add_endpoints(struct device *dev,
>  				   struct component_match **match,
>  				   struct device_node *port)
>  {
> -	struct device_node *ep, *remote;
> +	struct device_node *remote;
> +	int i;
>
> -	for_each_child_of_node(port, ep) {
> -		remote = of_graph_get_remote_port_parent(ep);
> -		if (!remote || !of_device_is_available(remote)) {
> -			of_node_put(remote);
> -			continue;
> -		} else if (!of_device_is_available(remote->parent)) {
> -			dev_warn(dev, "parent device of %s is not available\n",
> -				 remote->full_name);
> -			of_node_put(remote);
> +	for (i = 0; i < 3; i++) {
> +		remote = of_graph_get_remote_node(port, 0, i);
> +		if (!remote)
>  			continue;
> -		}
>
>  		drm_of_component_match_add(dev, match, compare_of, remote);
>  		of_node_put(remote);
> @@ -464,7 +458,7 @@ static int rockchip_drm_platform_probe(struct platform_device *pdev)
>  			continue;
>  		}
>
> -		rockchip_add_endpoints(dev, &match, port);
> +		rockchip_add_endpoints(dev, &match, port->parent);
>  		of_node_put(port);
>  	}
>
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> index 6dfdb145f3bb..d67f39e850a8 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> @@ -23,6 +23,7 @@
>  #include <linux/workqueue.h>
>  #include <linux/completion.h>
>  #include <linux/dma-mapping.h>
> +#include <linux/of_graph.h>
>
>  #include "tilcdc_drv.h"
>  #include "tilcdc_regs.h"
> @@ -1013,16 +1014,7 @@ int tilcdc_crtc_create(struct drm_device *dev)
>  	drm_crtc_helper_add(crtc, &tilcdc_crtc_helper_funcs);
>
>  	if (priv->is_componentized) {
> -		struct device_node *ports =
> -			of_get_child_by_name(dev->dev->of_node, "ports");
> -
> -		if (ports) {
> -			crtc->port = of_get_child_by_name(ports, "port");
> -			of_node_put(ports);
> -		} else {
> -			crtc->port =
> -				of_get_child_by_name(dev->dev->of_node, "port");
> -		}
> +		crtc->port = of_graph_get_port_by_id(dev->dev->of_node, 0);
>  		if (!crtc->port) { /* This should never happen */
>  			dev_err(dev->dev, "Port node not found in %s\n",
>  				dev->dev->of_node->full_name);
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_external.c b/drivers/gpu/drm/tilcdc/tilcdc_external.c
> index c67d7cd7d57e..19cf57a6ec76 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_external.c
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_external.c
> @@ -187,39 +187,6 @@ int tilcdc_attach_bridge(struct drm_device *ddev, struct drm_bridge *bridge)
>  	return ret;
>  }
>
> -static int tilcdc_node_has_port(struct device_node *dev_node)
> -{
> -	struct device_node *node;
> -
> -	node = of_get_child_by_name(dev_node, "ports");
> -	if (!node)
> -		node = of_get_child_by_name(dev_node, "port");
> -	if (!node)
> -		return 0;
> -	of_node_put(node);
> -
> -	return 1;
> -}
> -
> -static
> -struct device_node *tilcdc_get_remote_node(struct device_node *node)
> -{
> -	struct device_node *ep;
> -	struct device_node *parent;
> -
> -	if (!tilcdc_node_has_port(node))
> -		return NULL;
> -
> -	ep = of_graph_get_next_endpoint(node, NULL);
> -	if (!ep)
> -		return NULL;
> -
> -	parent = of_graph_get_remote_port_parent(ep);
> -	of_node_put(ep);
> -
> -	return parent;
> -}
> -
>  int tilcdc_attach_external_device(struct drm_device *ddev)
>  {
>  	struct tilcdc_drm_private *priv = ddev->dev_private;
> @@ -227,7 +194,7 @@ int tilcdc_attach_external_device(struct drm_device *ddev)
>  	struct drm_bridge *bridge;
>  	int ret;
>
> -	remote_node = tilcdc_get_remote_node(ddev->dev->of_node);
> +	remote_node = of_graph_get_remote_node(ddev->dev->of_node, 0, 0);
>  	if (!remote_node)
>  		return 0;
>
> @@ -266,35 +233,16 @@ int tilcdc_get_external_components(struct device *dev,
>  				   struct component_match **match)
>  {
>  	struct device_node *node;
> -	struct device_node *ep = NULL;
> -	int count = 0;
> -	int ret = 0;
> -
> -	if (!tilcdc_node_has_port(dev->of_node))
> -		return 0;
>
> -	while ((ep = of_graph_get_next_endpoint(dev->of_node, ep))) {
> -		node = of_graph_get_remote_port_parent(ep);
> -		if (!node || !of_device_is_available(node)) {
> -			of_node_put(node);
> -			continue;
> -		}
> -
> -		dev_dbg(dev, "Subdevice node '%s' found\n", node->name);
> -
> -		if (of_device_is_compatible(node, "nxp,tda998x")) {
> -			if (match)
> -				drm_of_component_match_add(dev, match,
> -							   dev_match_of, node);
> -			ret = 1;
> -		}
> +	node = of_graph_get_remote_node(dev->of_node, 0, 0);
>
> +	if (!of_device_is_compatible(node, "nxp,tda998x")) {
>  		of_node_put(node);
> -		if (count++ > 1) {
> -			dev_err(dev, "Only one port is supported\n");
> -			return -EINVAL;
> -		}
> +		return 0;
>  	}
>
> -	return ret;
> +	if (match)
> +		drm_of_component_match_add(dev, match, dev_match_of, node);
> +	of_node_put(node);
> +	return 1;
>  }
> diff --git a/drivers/gpu/drm/vc4/vc4_dpi.c b/drivers/gpu/drm/vc4/vc4_dpi.c
> index 1e1f6b8184d0..ac9655451b25 100644
> --- a/drivers/gpu/drm/vc4/vc4_dpi.c
> +++ b/drivers/gpu/drm/vc4/vc4_dpi.c
> @@ -366,23 +366,14 @@ static const struct of_device_id vc4_dpi_dt_match[] = {
>   */
>  static struct drm_panel *vc4_dpi_get_panel(struct device *dev)
>  {
> -	struct device_node *endpoint, *panel_node;
> +	struct device_node *panel_node;
>  	struct device_node *np = dev->of_node;
>  	struct drm_panel *panel;
>
> -	endpoint = of_graph_get_next_endpoint(np, NULL);
> -	if (!endpoint) {
> -		dev_err(dev, "no endpoint to fetch DPI panel\n");
> -		return NULL;
> -	}
> -
>  	/* don't proceed if we have an endpoint but no panel_node tied to it */
> -	panel_node = of_graph_get_remote_port_parent(endpoint);
> -	of_node_put(endpoint);
> -	if (!panel_node) {
> -		dev_err(dev, "no valid panel node\n");
> +	panel_node = of_graph_get_remote_node(np, 0, 0);
> +	if (!panel_node)
>  		return NULL;
> -	}
>
>  	panel = of_drm_find_panel(panel_node);
>  	of_node_put(panel_node);
> --
> 2.10.1

--
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