The point of this new change is to make the IIO tree actually parsable. Before, given this attribute as a filename: in_voltage0_aux_sample_rate Userspace had no way to know if the attribute name was "aux_sample_rate" with no extended name, or "sample_rate" with "aux" as the extended name, or just "rate" with "aux_sample" as the extended name. This was somewhat possible to deduce when there was more than one attribute present for a given channel, e.g: in_voltage0_aux_sample_rate in_voltage0_aux_frequency There, it was possible to deduce that "aux" was the extended name. But even with more than one attribute, this wasn't very robust, as two attributes starting with the same prefix (e.g. "sample_rate" and "sample_size") would result in the first part of the prefix being interpreted as being part of the extended name. To address the issue, knowing that channels will never have both a label and an extended name, set the channel's label to the extended name. In this case, the label's attribute will also have the extended name in its filename, but we can live with that - userspace can open in_voltage0_<prefix>_label and verify that it returns <prefix> to obtain the extended name. Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx> --- Notes: v3: Refactor code to make it look better drivers/iio/industrialio-core.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index 81f40dab778a..a19938b0c3a6 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -717,10 +717,13 @@ static ssize_t iio_read_channel_label(struct device *dev, 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 -EINVAL; + if (indio_dev->info->read_label) + return indio_dev->info->read_label(indio_dev, this_attr->c, buf); + + if (this_attr->c->extend_name) + return sprintf(buf, "%s\n", this_attr->c->extend_name); - return indio_dev->info->read_label(indio_dev, this_attr->c, buf); + return -EINVAL; } static ssize_t iio_read_channel_info(struct device *dev, @@ -1160,7 +1163,7 @@ static int iio_device_add_channel_label(struct iio_dev *indio_dev, struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); int ret; - if (!indio_dev->info->read_label) + if (!indio_dev->info->read_label && !chan->extend_name) return 0; ret = __iio_add_chan_devattr("label", -- 2.30.2