On Fri, 18 Sep 2020 12:33:02 +0300
Cristian Pop <cristian.pop@xxxxxxxxxx> wrote:
> If a label is defined in the device tree for this channel add that
> to the channel specific attributes. This is useful for userspace to
> be able to identify an individual channel.
>
> Signed-off-by: Cristian Pop <cristian.pop@xxxxxxxxxx>
> ---
> Changes in V5:
> Create patch for single commits.
Patch is fine, but should be in a series with the other two rather than
one patch per commit?
> drivers/iio/industrialio-core.c | 41 +++++++++++++++++++++++++++++++++
> include/linux/iio/iio.h | 6 +++++
> 2 files changed, 47 insertions(+)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 1527f01a44f1..49868e080840 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -643,6 +643,21 @@ ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
> }
> EXPORT_SYMBOL_GPL(iio_format_value);
>
> +static ssize_t iio_read_channel_label(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +
> + if (indio_dev->info->read_label)
> + return indio_dev->info->read_label(indio_dev,
> + this_attr->c,
> + buf);
> + else
> + return -EINVAL;
> +}
> +
> static ssize_t iio_read_channel_info(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> @@ -1111,6 +1126,25 @@ int __iio_add_chan_devattr(const char *postfix,
> return ret;
> }
>
> +static int iio_device_add_channel_label(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan)
> +{
> + int ret;
> +
> + ret = __iio_add_chan_devattr("label",
> + chan,
> + &iio_read_channel_label,
> + NULL,
> + 0,
> + IIO_SEPARATE,
> + &indio_dev->dev,
> + &indio_dev->channel_attr_list);
> + if (ret < 0)
> + return ret;
> +
> + return 1;
> +}
> +
> static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan,
> enum iio_shared_by shared_by,
> @@ -1241,6 +1275,13 @@ static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
> return ret;
> attrcount += ret;
>
> + if (indio_dev->info->read_label) {
> + ret = iio_device_add_channel_label(indio_dev, chan);
> + if (ret < 0)
> + return ret;
> + attrcount += ret;
> + }
> +
> if (chan->ext_info) {
> unsigned int i = 0;
> for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index a1be82e74c93..58b151f5321d 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -362,6 +362,8 @@ struct iio_trigger; /* forward declaration */
> * and max. For lists, all possible values are enumerated.
> * @write_raw: function to write a value to the device.
> * Parameters are the same as for read_raw.
> + * @read_label: function to request label name for a specified label,
> + * for better channel identification.
> * @write_raw_get_fmt: callback function to query the expected
> * format/precision. If not set by the driver, write_raw
> * returns IIO_VAL_INT_PLUS_MICRO.
> @@ -420,6 +422,10 @@ struct iio_info {
> int val2,
> long mask);
>
> + int (*read_label)(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + char *label);
> +
> int (*write_raw_get_fmt)(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan,
> long mask);
