Re: [PATCH v2 5/9] iio: inkern: Add a helper to query an available minimum raw value

On Tue, 23 May 2023 17:12:19 +0200 Herve Codina herve.codina@bootlin.com wrote:

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

Acked-by: Jonathan Cameron Jonathan.Cameron@huawei.com

---

drivers/iio/inkern.c | 70 ++++++++++++++++++++++++++++++++++++ include/linux/iio/consumer.h | 12 +++++++ 2 files changed, 82 insertions(+)

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c index f738db9a0c04..07b26ff8a334 100644 --- a/drivers/iio/inkern.c +++ b/drivers/iio/inkern.c @@ -915,6 +915,76 @@ int iio_read_max_channel_raw(struct iio_channel *chan, int *val) } 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)
  

+{

• int unused;
• const int *vals;
• int length;
• int ret;
• if (!val2)

• val2 = &unused;
  

• 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];
  

• 	*val2 = vals[1];
  

• }
  

• return 0;
  

• case IIO_AVAIL_LIST:

• if (length <= 0)
  

• 	return -EINVAL;
  

• switch (*type) {
  

• case IIO_VAL_INT:
  

• 	*val = vals[--length];
  

• 	while (length) {
  

• 		if (vals[--length] < *val)
  

• 			*val = vals[length];
  

• 	}
  

• 	break;
  

• default:
  

• 	/* FIXME: 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); diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h index f536820b9cf2..e9910b41d48e 100644 --- a/include/linux/iio/consumer.h +++ b/include/linux/iio/consumer.h @@ -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.