Re: [PATCH 13/23] gpio: mockup: pass the chip label as device property

[Andy Shevchenko]

On Fri, Sep 04, 2020 at 05:45:37PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> 
> While we do check the "chip-name" property in probe(), we never actually
> use it. Let's pass the chip label to the driver using device properties
> as we'll want to allow users to define their own once dynamically
> created chips are supported.
> 
> The property is renamed to "chip-label" to not cause any confusion with
> the actual chip name which is of the form: "gpiochipX".
> 
> If the "chip-label" property is missing, let's do what most devices in
> drivers/gpio/ do and use dev_name().

Just wondering if we have a documentation in kernel how this mockup mechanism
works and what kind of properties it uses.

Side note: moving to software nodes would make some advantages in future such
as visibility properties and their values (not yet implemented, but there is an
idea to move forward).

> Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> ---
>  drivers/gpio/gpio-mockup.c | 17 ++++++++---------
>  1 file changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
> index e8a19a28ed13..ce83f1df1933 100644
> --- a/drivers/gpio/gpio-mockup.c
> +++ b/drivers/gpio/gpio-mockup.c
> @@ -433,21 +433,14 @@ static int gpio_mockup_probe(struct platform_device *pdev)
>  	if (rv)
>  		return rv;
>  
> -	rv = device_property_read_string(dev, "chip-name", &name);
> +	rv = device_property_read_string(dev, "chip-label", &name);
>  	if (rv)
> -		name = NULL;
> +		name = dev_name(dev);
>  
>  	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
>  	if (!chip)
>  		return -ENOMEM;
>  
> -	if (!name) {
> -		name = devm_kasprintf(dev, GFP_KERNEL,
> -				      "%s-%c", pdev->name, pdev->id + 'A');
> -		if (!name)
> -			return -ENOMEM;
> -	}
> -
>  	mutex_init(&chip->lock);
>  
>  	gc = &chip->gc;
> @@ -534,6 +527,7 @@ static void gpio_mockup_unregister_devices(void)
>  static int __init gpio_mockup_init(void)
>  {
>  	struct property_entry properties[GPIO_MOCKUP_MAX_PROP];
> +	char chip_label[GPIO_MOCKUP_LABEL_SIZE];
>  	struct gpio_mockup_device *mockup_dev;
>  	int i, prop, num_chips, err = 0, base;
>  	struct platform_device_info pdevinfo;
> @@ -570,6 +564,11 @@ static int __init gpio_mockup_init(void)
>  		memset(&pdevinfo, 0, sizeof(pdevinfo));
>  		prop = 0;
>  
> +		snprintf(chip_label, sizeof(chip_label),
> +			 "gpio-mockup-%c", i + 'A');
> +		properties[prop++] = PROPERTY_ENTRY_STRING("chip-label",
> +							   chip_label);
> +
>  		base = gpio_mockup_range_base(i);
>  		if (base >= 0)
>  			properties[prop++] = PROPERTY_ENTRY_U32("gpio-base",
> -- 
> 2.26.1
> 

-- 
With Best Regards,
Andy Shevchenko