Re: [PATCH 7/7] staging:iio:ad7291: Rework regulator handling

[Jonathan Cameron <jic23@kernel.org>]

On 06/14/2013 04:58 PM, Lars-Peter Clausen wrote:
> Add platform_data for the driver which allows to specify whether an external
> reference voltage is used or not. It is not possible to use the return value of
> regulator_get() for this since the regulator framework is able to return a dummy
> regulator in case no regulator has been specified. In this case the driver will
> always get a valid regulator, no matter if it has been specified or not.  Also
> make the regulator non-optional if platform_data states that an external
> reference voltage should be used.
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Applied to the togreg branch of iio.git
> ---
>  drivers/staging/iio/adc/ad7291.c | 38 +++++++++++++++++++++++---------------
>  drivers/staging/iio/adc/ad7291.h | 12 ++++++++++++
>  2 files changed, 35 insertions(+), 15 deletions(-)
>  create mode 100644 drivers/staging/iio/adc/ad7291.h
> 
> diff --git a/drivers/staging/iio/adc/ad7291.c b/drivers/staging/iio/adc/ad7291.c
> index c2709d6..3fc79e5 100644
> --- a/drivers/staging/iio/adc/ad7291.c
> +++ b/drivers/staging/iio/adc/ad7291.c
> @@ -21,6 +21,8 @@
>  #include <linux/iio/sysfs.h>
>  #include <linux/iio/events.h>
>  
> +#include "ad7291.h"
> +
>  /*
>   * Simplified handling
>   *
> @@ -76,7 +78,6 @@
>  struct ad7291_chip_info {
>  	struct i2c_client	*client;
>  	struct regulator	*reg;
> -	u16			int_vref_mv;
>  	u16			command;
>  	u16			c_mask;	/* Active voltage channels for events */
>  	struct mutex		state_lock;
> @@ -445,7 +446,15 @@ static int ad7291_read_raw(struct iio_dev *indio_dev,
>  	case IIO_CHAN_INFO_SCALE:
>  		switch (chan->type) {
>  		case IIO_VOLTAGE:
> -			*val = chip->int_vref_mv;
> +			if (chip->reg) {
> +				int vref;
> +				vref = regulator_get_voltage(chip->reg);
> +				if (vref < 0)
> +					return vref;
> +				*val = vref / 1000;
> +			} else {
> +				*val = 2500;
> +			}
>  			*val2 = AD7291_BITS;
>  			return IIO_VAL_FRACTIONAL_LOG2;
>  		case IIO_TEMP:
> @@ -513,9 +522,10 @@ static const struct iio_info ad7291_info = {
>  static int ad7291_probe(struct i2c_client *client,
>  		const struct i2c_device_id *id)
>  {
> +	struct ad7291_platform_data *pdata = client->dev.platform_data;
>  	struct ad7291_chip_info *chip;
>  	struct iio_dev *indio_dev;
> -	int ret = 0, voltage_uv = 0;
> +	int ret = 0;
>  
>  	indio_dev = iio_device_alloc(sizeof(*chip));
>  	if (indio_dev == NULL) {
> @@ -524,12 +534,14 @@ static int ad7291_probe(struct i2c_client *client,
>  	}
>  	chip = iio_priv(indio_dev);
>  
> -	chip->reg = regulator_get(&client->dev, "vcc");
> -	if (!IS_ERR(chip->reg)) {
> +	if (pdata && pdata->use_external_ref) {
> +		chip->reg = regulator_get(&client->dev, "vref");
> +		if (IS_ERR(chip->reg))
> +			goto error_free;
> +
>  		ret = regulator_enable(chip->reg);
>  		if (ret)
>  			goto error_put_reg;
> -		voltage_uv = regulator_get_voltage(chip->reg);
>  	}
>  
>  	mutex_init(&chip->state_lock);
> @@ -542,12 +554,8 @@ static int ad7291_probe(struct i2c_client *client,
>  			AD7291_T_SENSE_MASK | /* Tsense always enabled */
>  			AD7291_ALERT_POLARITY; /* set irq polarity low level */
>  
> -	if (voltage_uv) {
> -		chip->int_vref_mv = voltage_uv / 1000;
> +	if (pdata && pdata->use_external_ref)
>  		chip->command |= AD7291_EXT_REF;
> -	} else {
> -		chip->int_vref_mv = 2500; /* Build-in ref */
> -	}
>  
>  	indio_dev->name = id->name;
>  	indio_dev->channels = ad7291_channels;
> @@ -590,12 +598,12 @@ error_unreg_irq:
>  	if (client->irq)
>  		free_irq(client->irq, indio_dev);
>  error_disable_reg:
> -	if (!IS_ERR(chip->reg))
> +	if (chip->reg)
>  		regulator_disable(chip->reg);
>  error_put_reg:
> -	if (!IS_ERR(chip->reg))
> +	if (chip->reg)
>  		regulator_put(chip->reg);
> -
> +error_free:
>  	iio_device_free(indio_dev);
>  error_ret:
>  	return ret;
> @@ -611,7 +619,7 @@ static int ad7291_remove(struct i2c_client *client)
>  	if (client->irq)
>  		free_irq(client->irq, indio_dev);
>  
> -	if (!IS_ERR(chip->reg)) {
> +	if (chip->reg) {
>  		regulator_disable(chip->reg);
>  		regulator_put(chip->reg);
>  	}
> diff --git a/drivers/staging/iio/adc/ad7291.h b/drivers/staging/iio/adc/ad7291.h
> new file mode 100644
> index 0000000..bbd89fa
> --- /dev/null
> +++ b/drivers/staging/iio/adc/ad7291.h
> @@ -0,0 +1,12 @@
> +#ifndef __IIO_AD7291_H__
> +#define __IIO_AD7291_H__
> +
> +/**
> + * struct ad7291_platform_data - AD7291 platform data
> + * @use_external_ref: Whether to use an external or internal reference voltage
> + */
> +struct ad7291_platform_data {
> +	bool use_external_ref;
> +};
> +
> +#endif
>