Re: [PATCH 1/2] ASoC: tlv320adcx140: Avoid accessing invalid gpio_reset

[Peter Ujfalusi <peter.ujfalusi@ti.com>]

On 08/09/2020 11.35, Camel Guo wrote:
> From: Camel Guo <camelg@axis.com>
> 
> When gpio_reset is not well defined in devicetree, the
> adcx140->gpio_reset is an error code instead of NULL. In this case,
> adcx140->gpio_reset should not be used by adcx140_reset. This commit
> sets it NULL to avoid accessing an invalid variable.
> 
> Signed-off-by: Camel Guo <camelg@axis.com>
> ---
>  sound/soc/codecs/tlv320adcx140.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/tlv320adcx140.c b/sound/soc/codecs/tlv320adcx140.c
> index 7ae6ec374be3..597dd1062943 100644
> --- a/sound/soc/codecs/tlv320adcx140.c
> +++ b/sound/soc/codecs/tlv320adcx140.c
> @@ -984,8 +984,10 @@ static int adcx140_i2c_probe(struct i2c_client *i2c,
>  
>  	adcx140->gpio_reset = devm_gpiod_get_optional(adcx140->dev,
>  						      "reset", GPIOD_OUT_LOW);
> -	if (IS_ERR(adcx140->gpio_reset))
> +	if (IS_ERR(adcx140->gpio_reset) || adcx140->gpio_reset == NULL) {
>  		dev_info(&i2c->dev, "Reset GPIO not defined\n");
> +		adcx140->gpio_reset = NULL;

the correct fix is to:
	dev_err(&i2c->dev, "Reset GPIO not defined\n");
	return PTR_ERR(adcx140->gpio_reset);

If the reset GPIO is specified and you get error when requesting it as
optional, there is a reason for that.
For example deferred probing.

> +	}
>  
>  	adcx140->supply_areg = devm_regulator_get_optional(adcx140->dev,
>  							   "areg");
> 

- Péter

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