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

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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: Marc Titinger <mtitinger@baylibre.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Marc Titinger 2015-12-11 17:49:15 +01:00 committed by Jonathan Cameron
parent f9993c0771
commit b17dc40155
1 changed files with 46 additions and 6 deletions
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52
drivers/iio/adc/ina2xx-adc.c
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@ -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);