Re: [PATCH v2 2/7] hwmon: (adc128d818) Use devm_regulator_get_enable_read_voltage()

[Guenter Roeck <linux@roeck-us.net>]

On 4/29/24 16:40, David Lechner wrote:
> We can reduce boilerplate code and eliminate the driver remove()
> function by using devm_regulator_get_enable_read_voltage().
> 
> A new external_vref flag is added since we no longer have the handle
> to the regulator to check if it is present.
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: David Lechner <dlechner@baylibre.com>

Nit below in case you resend, otherwise

Acked-by: Guenter Roeck <linux@roeck-us.net>

> ---
> 
> v2 changes:
> * rename to devm_regulator_get_enable_read_voltage()
> * use vref instead of err for return value
> * simplify last error check to return PTR_ERR directly
> ---
>   drivers/hwmon/adc128d818.c | 57 ++++++++++++++--------------------------------
>   1 file changed, 17 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/hwmon/adc128d818.c b/drivers/hwmon/adc128d818.c
> index 46e3c8c50765..2a35acb011eb 100644
> --- a/drivers/hwmon/adc128d818.c
> +++ b/drivers/hwmon/adc128d818.c
> @@ -58,7 +58,6 @@ static const u8 num_inputs[] = { 7, 8, 4, 6 };
>   
>   struct adc128_data {
>   	struct i2c_client *client;
> -	struct regulator *regulator;
>   	int vref;		/* Reference voltage in mV */
>   	struct mutex update_lock;
>   	u8 mode;		/* Operation mode */
> @@ -389,7 +388,7 @@ static int adc128_detect(struct i2c_client *client, struct i2c_board_info *info)
>   	return 0;
>   }
>   
> -static int adc128_init_client(struct adc128_data *data)
> +static int adc128_init_client(struct adc128_data *data, bool external_vref)
>   {
>   	struct i2c_client *client = data->client;
>   	int err;
> @@ -408,7 +407,7 @@ static int adc128_init_client(struct adc128_data *data)
>   		regval |= data->mode << 1;
>   
>   	/* If external vref is selected, configure the chip to use it */
> -	if (data->regulator)
> +	if (external_vref)
>   		regval |= 0x01;
>   
>   	/* Write advanced configuration register */
> @@ -430,9 +429,9 @@ static int adc128_init_client(struct adc128_data *data)
>   static int adc128_probe(struct i2c_client *client)
>   {
>   	struct device *dev = &client->dev;
> -	struct regulator *regulator;
>   	struct device *hwmon_dev;
>   	struct adc128_data *data;
> +	bool external_vref;
>   	int err, vref;
>   
>   	data = devm_kzalloc(dev, sizeof(struct adc128_data), GFP_KERNEL);
> @@ -440,20 +439,15 @@ static int adc128_probe(struct i2c_client *client)
>   		return -ENOMEM;
>   
>   	/* vref is optional. If specified, is used as chip reference voltage */
> -	regulator = devm_regulator_get_optional(dev, "vref");
> -	if (!IS_ERR(regulator)) {
> -		data->regulator = regulator;
> -		err = regulator_enable(regulator);
> -		if (err < 0)
> -			return err;
> -		vref = regulator_get_voltage(regulator);
> -		if (vref < 0) {
> -			err = vref;
> -			goto error;
> -		}
> -		data->vref = DIV_ROUND_CLOSEST(vref, 1000);
> -	} else {
> +	vref = devm_regulator_get_enable_read_voltage(dev, "vref");
> +	if (vref == -ENODEV) {
> +		external_vref = false;
>   		data->vref = 2560;	/* 2.56V, in mV */
> +	} else if (vref < 0) {
> +		return vref;
> +	} else {
> +		external_vref = true;
> +		data->vref = DIV_ROUND_CLOSEST(vref, 1000);
>   	}
>   
>   	/* Operation mode is optional. If unspecified, keep current mode */
> @@ -461,13 +455,12 @@ static int adc128_probe(struct i2c_client *client)
>   		if (data->mode > 3) {
>   			dev_err(dev, "invalid operation mode %d\n",
>   				data->mode);
> -			err = -EINVAL;
> -			goto error;
> +			return -EINVAL;
>   		}
>   	} else {
>   		err = i2c_smbus_read_byte_data(client, ADC128_REG_CONFIG_ADV);
>   		if (err < 0)
> -			goto error;
> +			return err;
>   		data->mode = (err >> 1) & ADC128_REG_MASK;
>   	}
>   
> @@ -476,31 +469,16 @@ static int adc128_probe(struct i2c_client *client)
>   	mutex_init(&data->update_lock);
>   
>   	/* Initialize the chip */
> -	err = adc128_init_client(data);
> +	err = adc128_init_client(data, external_vref);
>   	if (err < 0)
> -		goto error;
> +		return err;
>   
>   	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
>   							   data, adc128_groups);
> -	if (IS_ERR(hwmon_dev)) {
> -		err = PTR_ERR(hwmon_dev);
> -		goto error;
> -	}
> +	if (IS_ERR(hwmon_dev))
> +		return PTR_ERR(hwmon_dev);
>   
>   	return 0;

	return PTR_ERR_OR_ZERO(hwmon_dev);

> -
> -error:
> -	if (data->regulator)
> -		regulator_disable(data->regulator);
> -	return err;
> -}
> -
> -static void adc128_remove(struct i2c_client *client)
> -{
> -	struct adc128_data *data = i2c_get_clientdata(client);
> -
> -	if (data->regulator)
> -		regulator_disable(data->regulator);
>   }
>   
>   static const struct i2c_device_id adc128_id[] = {
> @@ -522,7 +500,6 @@ static struct i2c_driver adc128_driver = {
>   		.of_match_table = of_match_ptr(adc128_of_match),
>   	},
>   	.probe		= adc128_probe,
> -	.remove		= adc128_remove,
>   	.id_table	= adc128_id,
>   	.detect		= adc128_detect,
>   	.address_list	= normal_i2c,
>