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 <[email protected]>
---
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.
--
2.40.1
On Tue, 23 May 2023 17:12:19 +0200
Herve Codina <[email protected]> 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 <[email protected]>
Acked-by: Jonathan Cameron <[email protected]>
> ---
> 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.
Tue, May 23, 2023 at 05:12:19PM +0200, Herve Codina kirjoitti:
> 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().
...
> +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;
It's a single place, where this is used, can you move it there?
> + 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) {
while (length--) {
will do the job and at the same time...
> + if (vals[--length] < *val)
> + *val = vals[length];
...this construction becomes less confusing (easier to parse).
> + }
> + break;
> + default:
> + /* FIXME: learn about min for other iio values */
I believe in a final version this comment won't be here.
> + return -EINVAL;
> + }
> + return 0;
> +
> + default:
> + return -EINVAL;
> + }
> +}
--
With Best Regards,
Andy Shevchenko
On Sat, 3 Jun 2023 17:04:37 +0300
[email protected] wrote:
> Tue, May 23, 2023 at 05:12:19PM +0200, Herve Codina kirjoitti:
> > 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().
>
> ...
>
> > +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;
>
> It's a single place, where this is used, can you move it there?
I will do that in the next iteration.
Also, I will do the same modification in iio_channel_read_max() as it has
exactly the same code.
>
> > + 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) {
>
> while (length--) {
>
> will do the job and at the same time...
>
>
> > + if (vals[--length] < *val)
> > + *val = vals[length];
>
> ...this construction becomes less confusing (easier to parse).
Indeed, I will change in the next iteration.
>
> > + }
> > + break;
> > + default:
> > + /* FIXME: learn about min for other iio values */
>
> I believe in a final version this comment won't be here.
We have the same FIXME comment in the iio_channel_read_max() function I
copied to create this iio_channel_read_min() and, to be honest, I
don't really know how to handle these other cases.
In this series, I would prefer to keep this FIXME.
>
> > + return -EINVAL;
> > + }
> > + return 0;
> > +
> > + default:
> > + return -EINVAL;
> > + }
> > +}
>
Thanks for the review,
Hervé
On Mon, Jun 5, 2023 at 10:46 AM Herve Codina <[email protected]> wrote:
> On Sat, 3 Jun 2023 17:04:37 +0300
> [email protected] wrote:
> > Tue, May 23, 2023 at 05:12:19PM +0200, Herve Codina kirjoitti:
...
> > > + case IIO_VAL_INT:
> > > + *val = vals[--length];
> >
> > > + while (length) {
> >
> > while (length--) {
> >
> > will do the job and at the same time...
> >
> > > + if (vals[--length] < *val)
> > > + *val = vals[length];
> >
> > ...this construction becomes less confusing (easier to parse).
>
> Indeed, I will change in the next iteration.
And looking into above line, this whole construction I would prefer to
have a macro in minmax.h like
#define min_array(array, len) \
{( \
typeof(len) __len = (len); \
typeof(*(array)) __element = (array)[--__len]; \
while (__len--) \
__element = min(__element, (array)[__len]); \
__element; \
)}
(it might need more work, but you got the idea)
> > > + }
> > > + break;
...
> > > + default:
> > > + /* FIXME: learn about min for other iio values */
> >
> > I believe in a final version this comment won't be here.
>
> We have the same FIXME comment in the iio_channel_read_max() function I
> copied to create this iio_channel_read_min() and, to be honest, I
> don't really know how to handle these other cases.
>
> In this series, I would prefer to keep this FIXME.
I see, Jonathan needs to be involved here then.
> > > + return -EINVAL;
--
With Best Regards,
Andy Shevchenko
Hi Andy,
On Mon, 5 Jun 2023 12:45:24 +0300
Andy Shevchenko <[email protected]> wrote:
> On Mon, Jun 5, 2023 at 10:46 AM Herve Codina <[email protected]> wrote:
> > On Sat, 3 Jun 2023 17:04:37 +0300
> > [email protected] wrote:
> > > Tue, May 23, 2023 at 05:12:19PM +0200, Herve Codina kirjoitti:
>
> ...
>
> > > > + case IIO_VAL_INT:
> > > > + *val = vals[--length];
> > >
> > > > + while (length) {
> > >
> > > while (length--) {
> > >
> > > will do the job and at the same time...
> > >
> > > > + if (vals[--length] < *val)
> > > > + *val = vals[length];
> > >
> > > ...this construction becomes less confusing (easier to parse).
> >
> > Indeed, I will change in the next iteration.
>
> And looking into above line, this whole construction I would prefer to
> have a macro in minmax.h like
>
> #define min_array(array, len) \
> {( \
> typeof(len) __len = (len); \
> typeof(*(array)) __element = (array)[--__len]; \
> while (__len--) \
> __element = min(__element, (array)[__len]); \
> __element; \
> )}
>
> (it might need more work, but you got the idea)
I will also introduce max_array() and update both iio_channel_read_max()
and iio_channel_read_min() to use these macros.
Will be available in the next series iteration.
Thanks,
Hervé
>
> > > > + }
> > > > + break;
>
> ...
>
> > > > + default:
> > > > + /* FIXME: learn about min for other iio values */
> > >
> > > I believe in a final version this comment won't be here.
> >
> > We have the same FIXME comment in the iio_channel_read_max() function I
> > copied to create this iio_channel_read_min() and, to be honest, I
> > don't really know how to handle these other cases.
> >
> > In this series, I would prefer to keep this FIXME.
>
> I see, Jonathan needs to be involved here then.
>
> > > > + return -EINVAL;
>
Hi Jonathan, Andy,
On Mon, 5 Jun 2023 18:05:47 +0100
Jonathan Cameron <[email protected]> wrote:
> On Mon, 5 Jun 2023 12:45:24 +0300
> Andy Shevchenko <[email protected]> wrote:
>
...
> > > > > + default:
> > > > > + /* FIXME: learn about min for other iio values */
> > > >
> > > > I believe in a final version this comment won't be here.
> > >
> > > We have the same FIXME comment in the iio_channel_read_max() function I
> > > copied to create this iio_channel_read_min() and, to be honest, I
> > > don't really know how to handle these other cases.
> > >
> > > In this series, I would prefer to keep this FIXME.
> >
> > I see, Jonathan needs to be involved here then.
>
> It's really more of a TODO when someone needs it than a FIXME.
> I'm not particularly keen to see a bunch of code supporting cases
> that no one uses, but it's useful to call out where the code would
> go if other cases were to be supported.
>
> Perhaps soften it to a note that doesn't have the work FIXME in it.
>
> Jonathan
>
Right, I will change to /* TODO: learn about max for other iio values */
in the next iteration (both iio_channel_read_max() and iio_channel_read_min())
Regards,
Hervé
>
> >
> > > > > + return -EINVAL;
> >
>