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iio: inkern: Add a helper to query an available minimum raw value 

A helper, iio_read_max_channel_raw() exists to read the available
maximum raw value of a channel but nothing similar exists to read the
available minimum raw value.

This new helper, iio_read_min_channel_raw(), fills the hole and can be
used for reading the available minimum raw value of a channel.
It is fully based on the existing iio_read_max_channel_raw().

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20230623085830.749991-11-herve.codina@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Herve Codina 2023-06-23 10:58:27 +02:00 committed by Mark Brown
parent 4dc6037358
commit 7560418078
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GPG Key ID: 24D68B725D5487D0
2 changed files with 75 additions and 0 deletions
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63
drivers/iio/inkern.c
View File

@ -909,6 +909,69 @@ err_unlock:
}
EXPORT_SYMBOL_GPL(iio_read_max_channel_raw);
static int iio_channel_read_min(struct iio_channel *chan,
int *val, int *val2, int *type,
enum iio_chan_info_enum info)
{
const int *vals;
int length;
int ret;
ret = iio_channel_read_avail(chan, &vals, type, &length, info);
if (ret < 0)
return ret;
switch (ret) {
case IIO_AVAIL_RANGE:
switch (*type) {
case IIO_VAL_INT:
*val = vals[0];
break;
default:
*val = vals[0];
if (val2)
*val2 = vals[1];
}
return 0;
case IIO_AVAIL_LIST:
if (length <= 0)
return -EINVAL;
switch (*type) {
case IIO_VAL_INT:
*val = min_array(vals, length);
break;
default:
/* TODO: learn about min for other iio values */
return -EINVAL;
}
return 0;
default:
return -EINVAL;
}
}
int iio_read_min_channel_raw(struct iio_channel *chan, int *val)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(chan->indio_dev);
int ret;
int type;
mutex_lock(&iio_dev_opaque->info_exist_lock);
if (!chan->indio_dev->info) {
ret = -ENODEV;
goto err_unlock;
}
ret = iio_channel_read_min(chan, val, NULL, &type, IIO_CHAN_INFO_RAW);
err_unlock:
mutex_unlock(&iio_dev_opaque->info_exist_lock);
return ret;
}
EXPORT_SYMBOL_GPL(iio_read_min_channel_raw);
int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(chan->indio_dev);

12
include/linux/iio/consumer.h
View File

@ -301,6 +301,18 @@ int iio_write_channel_raw(struct iio_channel *chan, int val);
*/
int iio_read_max_channel_raw(struct iio_channel *chan, int *val);
/**
* iio_read_min_channel_raw() - read minimum available raw value from a given
* channel, i.e. the minimum possible value.
* @chan: The channel being queried.
* @val: Value read back.
*
* Note, if standard units are required, raw reads from iio channels
* need the offset (default 0) and scale (default 1) to be applied
* as (raw + offset) * scale.
*/
int iio_read_min_channel_raw(struct iio_channel *chan, int *val);
/**
* iio_read_avail_channel_raw() - read available raw values from a given channel
* @chan: The channel being queried.