linux-kernel - Re: [PATCH v3 12/14] iio: max1241: simplify using devm_regulator_get

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Date:   Fri, 19 Aug 2022 22:58:45 +0300
From:   Alexandru Lazar <alazar@...rtmail.com>
To:     Matti Vaittinen <mazziesaccount@...il.com>,
        Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 12/14] iio: max1241: simplify using
 devm_regulator_get_enable()

Heya,

I don't have the hardware at hand (long story, lots of smoke), so all I 
can do for this patch at the moment is:

Acked-by: Alexandru Lazar <alazar@...rtmail.com>

That being said, IIRC the MAX1241 has no special requirements in this 
regard, so if other SPI devices work, this one ought to work as well. If 
anyone's concerned, I can test it, but probably not sooner than a week 
or so :-(.

FWIW I really like this, the straightforward regulator boilerplate 
always felt a tad wrong.

All the best,
Alex

On 8/19/2022 10:20 PM, Matti Vaittinen wrote:
> Drop open-coded pattern: 'devm_regulator_get(), regulator_enable(),
> add_action_or_reset(regulator_disable)' and use the
> devm_regulator_get_enable() and drop the pointer to the regulator.
> This simplifies code and makes it less tempting to add manual control
> for the regulator which is also controlled by devm.
> 
> Signed-off-by: Matti Vaittinen <mazziesaccount@...il.com>
> 
> ---
> v2 => v3:
> New patch
> ---
>   drivers/iio/adc/max1241.c | 28 +++-------------------------
>   1 file changed, 3 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/iio/adc/max1241.c b/drivers/iio/adc/max1241.c
> index a815ad1f6913..500bb09ab19b 100644
> --- a/drivers/iio/adc/max1241.c
> +++ b/drivers/iio/adc/max1241.c
> @@ -22,7 +22,6 @@ enum max1241_id {
>   struct max1241 {
>   	struct spi_device *spi;
>   	struct mutex lock;
> -	struct regulator *vdd;
>   	struct regulator *vref;
>   	struct gpio_desc *shutdown;
>   
> @@ -110,17 +109,6 @@ static const struct iio_info max1241_info = {
>   	.read_raw = max1241_read_raw,
>   };
>   
> -static void max1241_disable_vdd_action(void *data)
> -{
> -	struct max1241 *adc = data;
> -	struct device *dev = &adc->spi->dev;
> -	int err;
> -
> -	err = regulator_disable(adc->vdd);
> -	if (err)
> -		dev_err(dev, "could not disable vdd regulator.\n");
> -}
> -
>   static void max1241_disable_vref_action(void *data)
>   {
>   	struct max1241 *adc = data;
> @@ -147,20 +135,10 @@ static int max1241_probe(struct spi_device *spi)
>   	adc->spi = spi;
>   	mutex_init(&adc->lock);
>   
> -	adc->vdd = devm_regulator_get(dev, "vdd");
> -	if (IS_ERR(adc->vdd))
> -		return dev_err_probe(dev, PTR_ERR(adc->vdd),
> -				     "failed to get vdd regulator\n");
> -
> -	ret = regulator_enable(adc->vdd);
> +	ret = devm_regulator_get_enable(dev, "vdd");
>   	if (ret)
> -		return ret;
> -
> -	ret = devm_add_action_or_reset(dev, max1241_disable_vdd_action, adc);
> -	if (ret) {
> -		dev_err(dev, "could not set up vdd regulator cleanup action\n");
> -		return ret;
> -	}
> +		return dev_err_probe(dev, ret,
> +				     "failed to get/enable vdd regulator\n");
>   
>   	adc->vref = devm_regulator_get(dev, "vref");
>   	if (IS_ERR(adc->vref))