Re: [PATCH 3/8] device property: Helper to match multiple connections

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

+Andy, Dan and Sakari

On Mon, Dec 27, 2021 at 09:21:11PM -0800, Bjorn Andersson wrote:
> In some cases multiple connections with the same connection id
> needs to be resolved from a fwnode graph.
> 
> One such example is when separate hardware is used for performing muxing and/or
> orientation switching of the SuperSpeed and SBU lines in a USB-C
> connector. In this case the connector needs to belong to a graph with
> multiple matching remote endpoints, and the TypeC controller needs to be
> able to resolve them both.
> 
> Add a new API that allows this kind of lookup.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  drivers/base/property.c  | 94 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/property.h |  5 +++
>  2 files changed, 99 insertions(+)
> 
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index cbe4fa298413..0aa0296fd991 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -1180,6 +1180,36 @@ fwnode_graph_devcon_match(struct fwnode_handle *fwnode, const char *con_id,
>  	return NULL;
>  }
>  
> +static unsigned int fwnode_graph_devcon_matches(struct fwnode_handle *fwnode,
> +						const char *con_id, void *data,
> +						devcon_match_fn_t match,
> +						void **matches,
> +						unsigned int matches_len)
> +{
> +	struct fwnode_handle *node;
> +	struct fwnode_handle *ep;
> +	unsigned int count = 0;
> +	void *ret;
> +
> +	fwnode_graph_for_each_endpoint(fwnode, ep) {
> +		if (count >= matches_len) {
> +			fwnode_handle_put(ep);
> +			return count;
> +		}
> +
> +		node = fwnode_graph_get_remote_port_parent(ep);
> +		if (!fwnode_device_is_available(node))
> +			continue;
> +
> +		ret = match(node, con_id, data);
> +		fwnode_handle_put(node);
> +
> +		if (ret)
> +			matches[count++] = ret;
> +	}
> +	return count;
> +}
> +
>  static void *
>  fwnode_devcon_match(struct fwnode_handle *fwnode, const char *con_id,
>  		    void *data, devcon_match_fn_t match)
> @@ -1202,6 +1232,35 @@ fwnode_devcon_match(struct fwnode_handle *fwnode, const char *con_id,
>  	return NULL;
>  }
>  
> +static unsigned int fwnode_devcon_matches(struct fwnode_handle *fwnode,
> +					  const char *con_id, void *data,
> +					  devcon_match_fn_t match,
> +					  void **matches,
> +					  unsigned int matches_len)
> +{
> +	struct fwnode_handle *node;
> +	unsigned int count = 0;
> +	void *ret;
> +	int i;
> +
> +	for (i = 0; ; i++) {
> +		if (count >= matches_len)
> +			return count;
> +
> +		node = fwnode_find_reference(fwnode, con_id, i);
> +		if (IS_ERR(node))
> +			break;
> +
> +		ret = match(node, NULL, data);
> +		fwnode_handle_put(node);
> +
> +		if (ret)
> +			matches[count++] = ret;
> +	}
> +
> +	return count;
> +}
> +
>  /**
>   * fwnode_connection_find_match - Find connection from a device node
>   * @fwnode: Device node with the connection
> @@ -1229,3 +1288,38 @@ void *fwnode_connection_find_match(struct fwnode_handle *fwnode,
>  	return fwnode_devcon_match(fwnode, con_id, data, match);
>  }
>  EXPORT_SYMBOL_GPL(fwnode_connection_find_match);
> +
> +/**
> + * fwnode_connection_find_matches - Find connections from a device node
> + * @fwnode: Device node with the connection
> + * @con_id: Identifier for the connection
> + * @data: Data for the match function
> + * @match: Function to check and convert the connection description
> + * @matches: Array of pointers to fill with matches
> + * @matches_len: Length of @matches
> + *
> + * Find up to @matches_len connections with unique identifier @con_id between
> + * @fwnode and other device nodes. @match will be used to convert the
> + * connection description to data the caller is expecting to be returned
> + * through the @matches array.
> + *
> + * Return: Number of matches resolved, of negative errno.
> + */
> +int fwnode_connection_find_matches(struct fwnode_handle *fwnode,
> +				   const char *con_id, void *data,
> +				   devcon_match_fn_t match,
> +				   void **matches, unsigned int matches_len)
> +{
> +	unsigned int count;
> +
> +	if (!fwnode || !match || !matches)
> +		return -EINVAL;
> +
> +	count = fwnode_graph_devcon_matches(fwnode, con_id, data, match,
> +					    matches, matches_len);
> +
> +	return count + fwnode_devcon_matches(fwnode, con_id, data, match,
> +					     matches + count,
> +					     matches_len - count);
> +}
> +EXPORT_SYMBOL_GPL(fwnode_connection_find_matches);
> diff --git a/include/linux/property.h b/include/linux/property.h
> index 16f736c698a2..59484ccb260e 100644
> --- a/include/linux/property.h
> +++ b/include/linux/property.h
> @@ -444,6 +444,11 @@ static inline void *device_connection_find_match(struct device *dev,
>  	return fwnode_connection_find_match(dev_fwnode(dev), con_id, data, match);
>  }
>  
> +int fwnode_connection_find_matches(struct fwnode_handle *fwnode,
> +				   const char *con_id, void *data,
> +				   devcon_match_fn_t match,
> +				   void **matches, unsigned int matches_len);
> +
>  /* -------------------------------------------------------------------------- */
>  /* Software fwnode support - when HW description is incomplete or missing */
>  
> -- 
> 2.33.1

-- 
heikki