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Date:   Mon, 29 Jun 2020 17:12:11 -0600
From:   Rob Herring <robh@kernel.org>
To:     Dmitry Osipenko <digetx@gmail.com>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Frank Rowand <frowand.list@gmail.com>,
        dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 1/7] of_graph: add of_graph_presents()
Message-ID: <20200629231211.GA3142766@bogus>
References: <20200617222703.17080-1-digetx@gmail.com>
 <20200617222703.17080-2-digetx@gmail.com>
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On Thu, Jun 18, 2020 at 01:26:57AM +0300, Dmitry Osipenko wrote:
> In some case, like a DRM display code for example, it's useful to silently
> check whether port node exists at all in a device-tree before proceeding
> with parsing of the graph.
> 
> This patch adds of_graph_presents() that returns true if given device-tree
> node contains OF graph port.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/of/property.c    | 52 +++++++++++++++++++++++++++++++++-------
>  include/linux/of_graph.h |  6 +++++
>  2 files changed, 49 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index 1f2086f4e7ce..b84ed6a7cf50 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -29,6 +29,48 @@
>  
>  #include "of_private.h"
>  
> +/**
> + * of_graph_get_first_local_port() - get first local port node
> + * @node: pointer to a local endpoint device_node
> + *
> + * Return: First local port node associated with local endpoint node linked
> + *	   to @node. Use of_node_put() on it when done.
> + */
> +static struct device_node *
> +of_graph_get_first_local_port(const struct device_node *node)
> +{
> +	struct device_node *ports, *port;
> +
> +	ports = of_get_child_by_name(node, "ports");
> +	if (ports)
> +		node = ports;
> +
> +	port = of_get_child_by_name(node, "port");
> +	of_node_put(ports);
> +
> +	return port;
> +}
> +
> +/**
> + * of_graph_presents() - check graph's presence
> + * @node: pointer to a device_node checked for the graph's presence
> + *
> + * Return: True if @node has a port or ports sub-node, false otherwise.
> + */
> +bool of_graph_presents(const struct device_node *node)

of_graph_is_present

Otherwise,

Reviewed-by: Rob Herring <robh@kernel.org>