Re: [PATCH 6/9] gpiolib-of: Reuse 'line-name' from DT as gpio descriptor name

[Johan Hovold <johan@xxxxxxxxxx>]

On Fri, Jul 17, 2015 at 11:32:47AM +0200, Markus Pargmann wrote:
> The DT describes gpios with subnodes. These subnodes can contain a
> property 'line-name'. This information can be useful in other areas
> where we want to identify a GPIO by its name.
> 
> This patch stores the line-name in the gpio descriptor.
> 
> Signed-off-by: Markus Pargmann <mpa@xxxxxxxxxxxxxx>
> ---
>  drivers/gpio/gpiolib-of.c | 29 ++++++++++++++++++++---------
>  1 file changed, 20 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
> index 64950591a764..cefc665a558c 100644
> --- a/drivers/gpio/gpiolib-of.c
> +++ b/drivers/gpio/gpiolib-of.c
> @@ -184,11 +184,6 @@ static struct gpio_desc *of_parse_gpio(struct device_node *np,
>  		*dflags |= GPIOD_OUT_LOW;
>  	else if (of_property_read_bool(np, "output-high"))
>  		*dflags |= GPIOD_OUT_HIGH;
> -	else {
> -		pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
> -			desc_to_gpio(gg_data.out_gpio), np->name);
> -		return ERR_PTR(-EINVAL);
> -	}
>
>  	if (name && of_property_read_string(np, "line-name", name))
>  		*name = np->name;
> @@ -214,15 +209,31 @@ static void of_gpiochip_scan_gpios(struct gpio_chip *chip)
>  
>  	for_each_child_of_node(chip->of_node, np) {
>  		const char *name = NULL;
> -		if (!of_property_read_bool(np, "gpio-hog"))
> -			continue;
> +		struct gpio_desc *name_desc;
>  
>  		desc = of_parse_gpio(np, &name, &lflags, &dflags);
>  		if (IS_ERR(desc))
>  			continue;
>  
> -		if (gpiod_hog(desc, name, lflags, dflags))
> -			continue;
> +		if (name) {
> +			name_desc = gpio_name_to_desc(name);
> +			if (name_desc)
> +				pr_err("GPIO name collision for '%s' detected at GPIO line %d (%s)\n",
> +				       name, desc_to_gpio(desc), np->name);
> +			else
> +				desc->name = name;

This will introduce a regression. As I mentioned in a comment on an
earlier patch, of_get_gpio_hog falls back to using the node name and
those need not be unique.

Johan
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