diff mbox series

[v6,04/13] iio: consumer.h: Fix raw values documentation notes

Message ID 20230623085830.749991-5-herve.codina@bootlin.com
State New
Headers
Series Add support for IIO devices in ASoC |

Commit Message

Herve Codina June 23, 2023, 8:58 a.m. UTC 
  The raw values notes mention 'ADC counts' and are not fully accurate.

Reword the notes in order to remove the 'ADC counts' and describe the
conversion needed between a raw value and a value in the standard units.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
 include/linux/iio/consumer.h | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

Comments

Christophe Leroy June 27, 2023, 9:55 a.m. UTC | #1 
Le 23/06/2023 à 10:58, Herve Codina a écrit :
> The raw values notes mention 'ADC counts' and are not fully accurate.
> 
> Reword the notes in order to remove the 'ADC counts' and describe the
> conversion needed between a raw value and a value in the standard units.
> 
> Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>

> ---
>   include/linux/iio/consumer.h | 25 +++++++++++++++----------
>   1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
> index 6802596b017c..f536820b9cf2 100644
> --- a/include/linux/iio/consumer.h
> +++ b/include/linux/iio/consumer.h
> @@ -201,8 +201,9 @@ struct iio_dev
>    * @chan:		The channel being queried.
>    * @val:		Value read back.
>    *
> - * Note raw reads from iio channels are in adc counts and hence
> - * scale will need to be applied if standard units required.
> + * 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_channel_raw(struct iio_channel *chan,
>   			 int *val);
> @@ -212,8 +213,9 @@ int iio_read_channel_raw(struct iio_channel *chan,
>    * @chan:		The channel being queried.
>    * @val:		Value read back.
>    *
> - * Note raw reads from iio channels are in adc counts and hence
> - * scale will need to be applied if standard units required.
> + * 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.
>    *
>    * In opposit to the normal iio_read_channel_raw this function
>    * returns the average of multiple reads.
> @@ -281,8 +283,9 @@ int iio_read_channel_attribute(struct iio_channel *chan, int *val,
>    * @chan:		The channel being queried.
>    * @val:		Value being written.
>    *
> - * Note raw writes to iio channels are in dac counts and hence
> - * scale will need to be applied if standard units required.
> + * Note that for raw writes to iio channels, if the value provided is
> + * in standard units, the affect of the scale and offset must be removed
> + * as (value / scale) - offset.
>    */
>   int iio_write_channel_raw(struct iio_channel *chan, int val);
>   
> @@ -292,8 +295,9 @@ int iio_write_channel_raw(struct iio_channel *chan, int val);
>    * @chan:		The channel being queried.
>    * @val:		Value read back.
>    *
> - * Note raw reads from iio channels are in adc counts and hence
> - * scale will need to be applied if standard units are required.
> + * 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_max_channel_raw(struct iio_channel *chan, int *val);
>   
> @@ -308,8 +312,9 @@ int iio_read_max_channel_raw(struct iio_channel *chan, int *val);
>    * For ranges, three vals are always returned; min, step and max.
>    * For lists, all the possible values are enumerated.
>    *
> - * Note raw available values from iio channels are in adc counts and
> - * hence scale will need to be applied if standard units are required.
> + * Note, if standard units are required, raw available values from iio
> + * channels need the offset (default 0) and scale (default 1) to be applied
> + * as (raw + offset) * scale.
>    */
>   int iio_read_avail_channel_raw(struct iio_channel *chan,
>   			       const int **vals, int *length);
diff mbox series

Patch

diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index 6802596b017c..f536820b9cf2 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -201,8 +201,9 @@  struct iio_dev
  * @chan:		The channel being queried.
  * @val:		Value read back.
  *
- * Note raw reads from iio channels are in adc counts and hence
- * scale will need to be applied if standard units required.
+ * 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_channel_raw(struct iio_channel *chan,
 			 int *val);
@@ -212,8 +213,9 @@  int iio_read_channel_raw(struct iio_channel *chan,
  * @chan:		The channel being queried.
  * @val:		Value read back.
  *
- * Note raw reads from iio channels are in adc counts and hence
- * scale will need to be applied if standard units required.
+ * 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.
  *
  * In opposit to the normal iio_read_channel_raw this function
  * returns the average of multiple reads.
@@ -281,8 +283,9 @@  int iio_read_channel_attribute(struct iio_channel *chan, int *val,
  * @chan:		The channel being queried.
  * @val:		Value being written.
  *
- * Note raw writes to iio channels are in dac counts and hence
- * scale will need to be applied if standard units required.
+ * Note that for raw writes to iio channels, if the value provided is
+ * in standard units, the affect of the scale and offset must be removed
+ * as (value / scale) - offset.
  */
 int iio_write_channel_raw(struct iio_channel *chan, int val);
 
@@ -292,8 +295,9 @@  int iio_write_channel_raw(struct iio_channel *chan, int val);
  * @chan:		The channel being queried.
  * @val:		Value read back.
  *
- * Note raw reads from iio channels are in adc counts and hence
- * scale will need to be applied if standard units are required.
+ * 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_max_channel_raw(struct iio_channel *chan, int *val);
 
@@ -308,8 +312,9 @@  int iio_read_max_channel_raw(struct iio_channel *chan, int *val);
  * For ranges, three vals are always returned; min, step and max.
  * For lists, all the possible values are enumerated.
  *
- * Note raw available values from iio channels are in adc counts and
- * hence scale will need to be applied if standard units are required.
+ * Note, if standard units are required, raw available values from iio
+ * channels need the offset (default 0) and scale (default 1) to be applied
+ * as (raw + offset) * scale.
  */
 int iio_read_avail_channel_raw(struct iio_channel *chan,
 			       const int **vals, int *length);