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Commit b17dc401 authored by Marc Titinger's avatar Marc Titinger Committed by Jonathan Cameron
Browse files

iio: ina2xx: re-instate a sysfs show/store for the shunt resistor value 



Different probe modules use different resistor values. The front-end
application may read a probe ID (from eeprom) and set the shunt value
accordingly.

Signed-off-by: default avatarMarc Titinger <mtitinger@baylibre.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent f9993c07

drivers/iio/adc/ina2xx-adc.c

+46 −6
Original line number Diff line number Diff line
@@ -111,7 +111,7 @@ struct ina2xx_chip_info { 
	struct task_struct *task;

	const struct ina2xx_config *config;

	struct mutex state_lock;

	long rshunt;

	unsigned int shunt_resistor;

	int avg;

	s64 prev_ns;	/* track buffer capture time, check for underruns*/

	int int_time_vbus; /* Bus voltage integration time uS */
@@ -349,6 +349,42 @@ static ssize_t ina2xx_allow_async_readout_store(struct device *dev, 
	return len;

}



static int set_shunt_resistor(struct ina2xx_chip_info *chip, unsigned int val)

{

	if (val <= 0 || val > chip->config->calibration_factor)

		return -EINVAL;



	chip->shunt_resistor = val;

	return 0;

}



static ssize_t ina2xx_shunt_resistor_show(struct device *dev,

					  struct device_attribute *attr,

					  char *buf)

{

	struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));



	return sprintf(buf, "%d\n", chip->shunt_resistor);

}



static ssize_t ina2xx_shunt_resistor_store(struct device *dev,

					   struct device_attribute *attr,

					   const char *buf, size_t len)

{

	struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));

	unsigned long val;

	int ret;



	ret = kstrtoul((const char *) buf, 10, &val);

	if (ret)

		return ret;



	ret = set_shunt_resistor(chip, val);

	if (ret)

		return ret;



	return len;

}



#define INA2XX_CHAN(_type, _index, _address) { \

	.type = (_type), \
@@ -545,9 +581,14 @@ static IIO_DEVICE_ATTR(in_allow_async_readout, S_IRUGO | S_IWUSR, 
		       ina2xx_allow_async_readout_show,

		       ina2xx_allow_async_readout_store, 0);



static IIO_DEVICE_ATTR(in_shunt_resistor, S_IRUGO | S_IWUSR,

		       ina2xx_shunt_resistor_show,

		       ina2xx_shunt_resistor_store, 0);



static struct attribute *ina2xx_attributes[] = {

	&iio_dev_attr_in_allow_async_readout.dev_attr.attr,

	&iio_const_attr_integration_time_available.dev_attr.attr,

	&iio_dev_attr_in_shunt_resistor.dev_attr.attr,

	NULL,

};
@@ -579,7 +620,7 @@ static int ina2xx_init(struct ina2xx_chip_info *chip, unsigned int config) 
	 * to the user for now.

	 */

	regval = DIV_ROUND_CLOSEST(chip->config->calibration_factor,

			    chip->rshunt);

			    chip->shunt_resistor);



	return regmap_write(chip->regmap, INA2XX_CALIBRATION, regval);

}
@@ -612,10 +653,9 @@ static int ina2xx_probe(struct i2c_client *client, 
			val = INA2XX_RSHUNT_DEFAULT;

	}



	if (val <= 0 || val > chip->config->calibration_factor)

		return -ENODEV;



	chip->rshunt = val;

	ret = set_shunt_resistor(chip, val);

	if (ret)

		return ret;



	mutex_init(&chip->state_lock);