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SubjectRe: [PATCH V7] iio: light: isl29018: add vcc regulator operation support
On Mon, 17 Dec 2018 03:25:17 +0000
Anson Huang <anson.huang@nxp.com> wrote:

> The light sensor's power supply could be controllable 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 vcc regulator operation support.
>
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Hi Anson

See below.

> ---
> ChangeLog since V6
> - using devm_regulator_get() instead of devm_regulator_get_optional() since the regulator is
> there anyway, if dtb does NOT specify one, regulator framework will assign dummy regulator for it;
> - Setup devm action for cleaning up regulator resource for error handling.
> ---
> drivers/iio/light/isl29018.c | 58 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 58 insertions(+)
>
> diff --git a/drivers/iio/light/isl29018.c b/drivers/iio/light/isl29018.c
> index b45400f..63f7b9d 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,
> @@ -708,6 +710,17 @@ static const char *isl29018_match_acpi_device(struct device *dev, int *data)
> return dev_name(dev);
> }
>
> +static void isl29018_disable_regulator_action(void *_data)
> +{
> + struct isl29018_chip *chip = _data;
> + int err;
> +
> + err = regulator_disable(chip->vcc_reg);
> + if (err)
> + dev_err(regmap_get_device(chip->regmap),
> + "failed to disable VCC regulator!\n");
> +}
> +
> static int isl29018_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> @@ -742,6 +755,37 @@ static int isl29018_probe(struct i2c_client *client,
> chip->scale = isl29018_scales[chip->int_time][0];
> chip->suspended = false;
>
> + chip->vcc_reg = devm_regulator_get(&client->dev, "vcc");
> + if (IS_ERR(chip->vcc_reg)) {
> + err = PTR_ERR(chip->vcc_reg);
> + if (err != -EPROBE_DEFER)
> + dev_err(&client->dev, "failed to get VCC regulator!\n");
> + return err;
> + }
> +
> + err = regulator_enable(chip->vcc_reg);
> + if (err) {
> + dev_err(&client->dev, "failed to enable VCC regulator!\n");
> + return err;
> + }
> +
> + chip->regmap = devm_regmap_init_i2c(client,
> + isl29018_chip_info_tbl[dev_id].regmap_cfg);
> + if (IS_ERR(chip->regmap)) {
> + err = PTR_ERR(chip->regmap);
> + dev_err(&client->dev, "regmap initialization fails: %d\n", err);
> + regulator_disable(chip->vcc_reg);
> + return err;
> + }
> +
> + err = devm_add_action(&client->dev, isl29018_disable_regulator_action,
> + chip);
> + if (err) {

I'm a little confused, why not do this before devm_regmap_init_i2c.
That way you won't have to disable the regulator in that one error path.
Also, devm_add_action_or_reset will call isl29018_disable_regulator_action for
you on error.

> + isl29018_disable_regulator_action(chip);
> + dev_err(&client->dev, "failed to setup regulator cleanup action!\n");
> + return err;
> + }
> +
> chip->regmap = devm_regmap_init_i2c(client,
> isl29018_chip_info_tbl[dev_id].regmap_cfg);
> if (IS_ERR(chip->regmap)) {
> @@ -768,6 +812,7 @@ 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 +822,12 @@ static int isl29018_suspend(struct device *dev)
> * So we do not have much to do here.
> */
> chip->suspended = true;
> + ret = regulator_disable(chip->vcc_reg);
> + if (ret) {
> + dev_err(dev, "failed to disable VCC regulator\n");
> + mutex_unlock(&chip->lock);
> + return ret;

Given you are about to unlock anyway a common pattern is to not
check ret until after the unlock, thus simplifying the code.

> + }
>
> mutex_unlock(&chip->lock);
>
> @@ -790,6 +841,13 @@ static int isl29018_resume(struct device *dev)
>
> mutex_lock(&chip->lock);
>
> + 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;

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