[PATCH 2/3] dm: button: add support for linux_code in button-gpio.c driver

[Quentin Schulz]

Hi Dzmitry,

On 1/11/23 11:19, Dzmitry Sankouski wrote:
> Linux event code may be used in input devices, using buttons.
> 
> Signed-off-by: Dzmitry Sankouski <dsankouski at gmail.com>
> ---
>   drivers/button/button-gpio.c   | 20 ++++++++++++++++++++
>   drivers/button/button-uclass.c | 10 ++++++++++
>   include/button.h               | 16 ++++++++++++++++
>   3 files changed, 46 insertions(+)
> 
> diff --git a/drivers/button/button-gpio.c b/drivers/button/button-gpio.c
> index dbb000622c..e6eff5c1da 100644
> --- a/drivers/button/button-gpio.c
> +++ b/drivers/button/button-gpio.c
> @@ -13,6 +13,7 @@
>   
>   struct button_gpio_priv {
>   	struct gpio_desc gpio;
> +	u32 linux_code;
>   };
>   
>   static enum button_state_t button_gpio_get_state(struct udevice *dev)
> @@ -29,10 +30,22 @@ static enum button_state_t button_gpio_get_state(struct udevice *dev)
>   	return ret ? BUTTON_ON : BUTTON_OFF;
>   }
>   
> +static u32 button_gpio_get_code(struct udevice *dev)
> +{
> +	struct button_gpio_priv *priv = dev_get_priv(dev);
> +	u32 code = priv->linux_code;
> +
> +	if (!code)
> +		return 0;
> +
> +	return code;
> +}
> +
>   static int button_gpio_probe(struct udevice *dev)
>   {
>   	struct button_uc_plat *uc_plat = dev_get_uclass_plat(dev);
>   	struct button_gpio_priv *priv = dev_get_priv(dev);
> +	u32 linux_code;
>   	int ret;
>   
>   	/* Ignore the top-level button node */
> @@ -43,6 +56,12 @@ static int button_gpio_probe(struct udevice *dev)
>   	if (ret)
>   		return ret;
>   
> +	linux_code = dev_read_u32_default(dev, "linux,code", -ENODATA);
> +	debug("linux code value: %d, ret: %d", linux_code, ret);
> +	if (ret)
> +		return ret;

ret is not modified here so it'll always pass even if it fails to parse 
dev_read_u32_default.

I believe dev_read_u32_default incorrectly requests an int as last 
argument while it's going to fill it with u32 data on success. 
dev_read_u8/u16 get this correctly so that might just be an oversight.

Please use dev_read_u32 instead:

ret = dev_read_u32(dev, "linux,code", &priv->linux_code);
debug("linux code value: %d, ret: %d", linux_code, ret);
return ret;

(no need to check the value of ret since it's the same as
if (ret)
     return ret;

return 0;
)

Cheers,
Quentin