linux-kernel - Re: [PATCH v1 2/4] gpio: add parameter to allow the use named gpios

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Date:	Wed, 7 Jan 2015 16:15:37 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Olliver Schinagl <oliver+list@...inagl.nl>
Cc:	Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Alexandre Courbot <gnurou@...il.com>,
	Bryan Wu <cooloney@...il.com>,
	Richard Purdie <rpurdie@...ys.net>,
	Olliver Schinagl <oliver@...inagl.nl>,
	Robin Gong <b38343@...escale.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Aaron Lu <aaron.lu@...el.com>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Grant Likely <grant.likely@...aro.org>,
	Wolfram Sang <wsa@...-dreams.de>,
	Alexander Shiyan <shc_work@...l.ru>,
	Jingoo Han <jg1.han@...sung.com>, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
	linux-input@...r.kernel.org, linux-leds@...r.kernel.org
Subject: Re: [PATCH v1 2/4] gpio: add parameter to allow the use named gpios

On Wed, Jan 07, 2015 at 10:08:40AM +0100, Olliver Schinagl wrote:
> From: Olliver Schinagl <oliver@...inagl.nl>
> 
> The gpio binding document says that new code should always use named
> gpios. Patch 40b73183 added support to parse a list of gpios from child
> nodes, but does not make it possible to use named gpios. This patch adds
> the con_id property and implements it is done in gpiolib.c, where the
> old-style of using unnamed gpios still works.
> 
> Signed-off-by: Olliver Schinagl <oliver@...inagl.nl>
> ---
>  drivers/gpio/devres.c                     | 16 +++++++++++++++-
>  drivers/input/keyboard/gpio_keys_polled.c |  2 +-
>  drivers/leds/leds-gpio.c                  |  2 +-
>  include/linux/gpio/consumer.h             |  1 +
>  4 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c
> index 13dbd3d..b7fbe1c 100644
> --- a/drivers/gpio/devres.c
> +++ b/drivers/gpio/devres.c
> @@ -111,23 +111,37 @@ EXPORT_SYMBOL(__devm_gpiod_get_index);
>  /**
>   * devm_get_gpiod_from_child - get a GPIO descriptor from a device's child node
>   * @dev:	GPIO consumer
> + * @con_id:	function within the GPIO consumer
>   * @child:	firmware node (child of @dev)
>   *
>   * GPIO descriptors returned from this function are automatically disposed on
>   * driver detach.
>   */
>  struct gpio_desc *devm_get_gpiod_from_child(struct device *dev,
> +					    const char *con_id,
>  					    struct fwnode_handle *child)
>  {
> +	static const char const *suffixes[] = { "gpios", "gpio" };
> +	char prop_name[32]; /* 32 is max size of property name */
>  	struct gpio_desc **dr;
>  	struct gpio_desc *desc;
> +	unsigned int i;
>  
>  	dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
>  			  GFP_KERNEL);
>  	if (!dr)
>  		return ERR_PTR(-ENOMEM);
>  
> -	desc = fwnode_get_named_gpiod(child, "gpios");
> +	for (i = 0; i < ARRAY_SIZE(suffixes); i++) {
> +		if (con_id)
> +			snprintf(prop_name, 32, "%s-%s", con_id, suffixes[i]);

sizeof(prop_name) instead of hard-coding 32 would be better.

> +		else
> +			snprintf(prop_name, 32, "%s", suffixes[i]);
> +
> +		desc = fwnode_get_named_gpiod(child, prop_name);
> +		if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
> +			break;
> +	}
>  	if (IS_ERR(desc)) {
>  		devres_free(dr);
>  		return desc;
> diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c
> index 90df4df..097d721 100644
> --- a/drivers/input/keyboard/gpio_keys_polled.c
> +++ b/drivers/input/keyboard/gpio_keys_polled.c
> @@ -125,7 +125,7 @@ static struct gpio_keys_platform_data *gpio_keys_polled_get_devtree_pdata(struct
>  	device_for_each_child_node(dev, child) {
>  		struct gpio_desc *desc;
>  
> -		desc = devm_get_gpiod_from_child(dev, child);
> +		desc = devm_get_gpiod_from_child(dev, NULL, child);

I guess the number of users is small enough that we can do this API
change in one step if gpio overlords are happy with it.

>  		if (IS_ERR(desc)) {
>  			error = PTR_ERR(desc);
>  			if (error != -EPROBE_DEFER)
> diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c
> index 7ea1ea42..8e5af69 100644
> --- a/drivers/leds/leds-gpio.c
> +++ b/drivers/leds/leds-gpio.c
> @@ -184,7 +184,7 @@ static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
>  		struct gpio_led led = {};
>  		const char *state = NULL;
>  
> -		led.gpiod = devm_get_gpiod_from_child(dev, child);
> +		led.gpiod = devm_get_gpiod_from_child(dev, NULL, child);
>  		if (IS_ERR(led.gpiod)) {
>  			fwnode_handle_put(child);
>  			goto err;
> diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
> index 45afc2d..ed20759 100644
> --- a/include/linux/gpio/consumer.h
> +++ b/include/linux/gpio/consumer.h
> @@ -110,6 +110,7 @@ struct fwnode_handle;
>  struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
>  					 const char *propname);
>  struct gpio_desc *devm_get_gpiod_from_child(struct device *dev,
> +					    const char *con_id,
>  					    struct fwnode_handle *child);
>  #else /* CONFIG_GPIOLIB */
>  
> -- 
> 2.1.4
> 

Thanks.

-- 
Dmitry
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