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iio/adc: (max1363) Add support for external reference voltage 

Implement external reference voltage as regulator named "vref".

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
hifive-unleashed-5.1
Guenter Roeck 2013-02-03 00:59:00 +00:00 committed by Jonathan Cameron
parent 7c3e8675f3
commit a405b00e44
1 changed files with 39 additions and 13 deletions
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52
drivers/iio/adc/max1363.c
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@ -163,6 +163,8 @@ struct max1363_chip_info {
* @mask_low: bitmask for enabled low thresholds
* @thresh_high: high threshold values
* @thresh_low: low threshold values
* @vref: Reference voltage regulator
* @vref_uv: Actual (external or internal) reference voltage
*/
struct max1363_state {
struct i2c_client *client;
@ -182,6 +184,8 @@ struct max1363_state {
/* 4x unipolar first then the fours bipolar ones */
s16 thresh_high[8];
s16 thresh_low[8];
struct regulator *vref;
u32 vref_uv;
};
#define MAX1363_MODE_SINGLE(_num, _mask) { \
@ -393,6 +397,8 @@ static int max1363_read_raw(struct iio_dev *indio_dev,
{
struct max1363_state *st = iio_priv(indio_dev);
int ret;
unsigned long scale_uv;
switch (m) {
case IIO_CHAN_INFO_RAW:
ret = max1363_read_single_chan(indio_dev, chan, val, m);
@ -400,16 +406,10 @@ static int max1363_read_raw(struct iio_dev *indio_dev,
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
if ((1 << (st->chip_info->bits + 1)) >
st->chip_info->int_vref_mv) {
*val = 0;
*val2 = 500000;
return IIO_VAL_INT_PLUS_MICRO;
} else {
*val = (st->chip_info->int_vref_mv)
>> st->chip_info->bits;
return IIO_VAL_INT;
}
scale_uv = st->vref_uv >> st->chip_info->bits;
*val = scale_uv / 1000;
*val2 = (scale_uv % 1000) * 1000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
@ -1390,12 +1390,16 @@ static const struct max1363_chip_info max1363_chip_info_tbl[] = {
static int max1363_initial_setup(struct max1363_state *st)
{
st->setupbyte = MAX1363_SETUP_AIN3_IS_AIN3_REF_IS_VDD
| MAX1363_SETUP_POWER_UP_INT_REF
| MAX1363_SETUP_INT_CLOCK
st->setupbyte = MAX1363_SETUP_INT_CLOCK
| MAX1363_SETUP_UNIPOLAR
| MAX1363_SETUP_NORESET;
if (st->vref)
st->setupbyte |= MAX1363_SETUP_AIN3_IS_REF_EXT_TO_REF;
else
st->setupbyte |= MAX1363_SETUP_POWER_UP_INT_REF
| MAX1363_SETUP_AIN3_IS_AIN3_REF_IS_INT;
/* Set scan mode writes the config anyway so wait until then */
st->setupbyte = MAX1363_SETUP_BYTE(st->setupbyte);
st->current_mode = &max1363_mode_table[st->chip_info->default_mode];
@ -1491,6 +1495,7 @@ static int max1363_probe(struct i2c_client *client,
int ret;
struct max1363_state *st;
struct iio_dev *indio_dev;
struct regulator *vref;
indio_dev = iio_device_alloc(sizeof(struct max1363_state));
if (indio_dev == NULL) {
@ -1521,6 +1526,23 @@ static int max1363_probe(struct i2c_client *client,
st->chip_info = &max1363_chip_info_tbl[id->driver_data];
st->client = client;
st->vref_uv = st->chip_info->int_vref_mv * 1000;
vref = devm_regulator_get(&client->dev, "vref");
if (!IS_ERR(vref)) {
int vref_uv;
ret = regulator_enable(vref);
if (ret)
goto error_disable_reg;
st->vref = vref;
vref_uv = regulator_get_voltage(vref);
if (vref_uv <= 0) {
ret = -EINVAL;
goto error_disable_reg;
}
st->vref_uv = vref_uv;
}
ret = max1363_alloc_scan_masks(indio_dev);
if (ret)
goto error_disable_reg;
@ -1562,6 +1584,8 @@ static int max1363_probe(struct i2c_client *client,
error_uninit_buffer:
iio_triggered_buffer_cleanup(indio_dev);
error_disable_reg:
if (st->vref)
regulator_disable(st->vref);
regulator_disable(st->reg);
error_unregister_map:
iio_map_array_unregister(indio_dev);
@ -1578,6 +1602,8 @@ static int max1363_remove(struct i2c_client *client)
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
if (st->vref)
regulator_disable(st->vref);
regulator_disable(st->reg);
iio_map_array_unregister(indio_dev);
iio_device_free(indio_dev);