linux-kernel - Re: [PATCH V2] iio: light: isl29018: add optional vcc regulator operation support

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Message-ID: <20181208120907.4cd1a755@archlinux>
Date:   Sat, 8 Dec 2018 12:09:07 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Anson Huang <anson.huang@....com>
Cc:     "knaack.h@....de" <knaack.h@....de>,
        "lars@...afoo.de" <lars@...afoo.de>,
        "pmeerw@...erw.net" <pmeerw@...erw.net>,
        "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>
Subject: Re: [PATCH V2] iio: light: isl29018: add optional vcc regulator
 operation support

On Thu, 6 Dec 2018 03:33:16 +0000
Anson Huang <anson.huang@....com> wrote:

> The light sensor's power supply could be controlled by regulator
> on some platforms, such as i.MX6Q-SABRESD board, the light sensor
> isl29023's power supply is controlled by a GPIO fixed regulator,
> need to make sure the regulator is enabled before any operation of
> sensor, this patch adds optional vcc regulator operation support.
> 
> Signed-off-by: Anson Huang <Anson.Huang@....com>
> ---
> ChangeLog:
> 	replace "VDD" with "VCC" since the regulator name is vcc_reg.
Fabio has raised naming concerns so I'll assume we'll see a v3 with that.

One other comment inline.

Jonathan

> ---
>  drivers/iio/light/isl29018.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/iio/light/isl29018.c b/drivers/iio/light/isl29018.c
> index b45400f..87dcbce 100644
> --- a/drivers/iio/light/isl29018.c
> +++ b/drivers/iio/light/isl29018.c
> @@ -23,6 +23,7 @@
>  #include <linux/mutex.h>
>  #include <linux/delay.h>
>  #include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/slab.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> @@ -95,6 +96,7 @@ struct isl29018_chip {
>  	struct isl29018_scale	scale;
>  	int			prox_scheme;
>  	bool			suspended;
> +	struct regulator	*vcc_reg;
>  };
>  
>  static int isl29018_set_integration_time(struct isl29018_chip *chip,
> @@ -735,6 +737,15 @@ static int isl29018_probe(struct i2c_client *client,
>  
>  	mutex_init(&chip->lock);
>  
> +	chip->vcc_reg = devm_regulator_get_optional(&client->dev, "vcc");
> +	if (!IS_ERR(chip->vcc_reg)) {

We should probably handle the case of deferred explicitly rather than
assuming all errors mean the regulator hasn't been provided.

> +		err = regulator_enable(chip->vcc_reg);
> +		if (err) {
> +			dev_err(&client->dev, "failed to enable VCC regulator\n");
> +			return err;
> +		}
> +	}
> +
>  	chip->type = dev_id;
>  	chip->calibscale = 1;
>  	chip->ucalibscale = 0;
> @@ -768,6 +779,7 @@ static int isl29018_probe(struct i2c_client *client,
>  static int isl29018_suspend(struct device *dev)
>  {
>  	struct isl29018_chip *chip = iio_priv(dev_get_drvdata(dev));
> +	int ret;
>  
>  	mutex_lock(&chip->lock);
>  
> @@ -777,6 +789,14 @@ static int isl29018_suspend(struct device *dev)
>  	 * So we do not have much to do here.
>  	 */
>  	chip->suspended = true;
> +	if (!IS_ERR(chip->vcc_reg)) {
> +		ret = regulator_disable(chip->vcc_reg);
> +		if (ret) {
> +			dev_err(dev, "failed to disable VCC regulator\n");
> +			mutex_unlock(&chip->lock);
> +			return ret;
> +		}
> +	}
>  
>  	mutex_unlock(&chip->lock);
>  
> @@ -790,6 +810,15 @@ static int isl29018_resume(struct device *dev)
>  
>  	mutex_lock(&chip->lock);
>  
> +	if (!IS_ERR(chip->vcc_reg)) {
> +		err = regulator_enable(chip->vcc_reg);
> +		if (err) {
> +			dev_err(dev, "failed to enable VCC regulator\n");
> +			mutex_unlock(&chip->lock);
> +			return err;
> +		}
> +	}
> +
>  	err = isl29018_chip_init(chip);
>  	if (!err)
>  		chip->suspended = false;