On Thu, 20 Jun 2024 17:13:08 -0400
Sean Anderson <sean.anderson@xxxxxxxxx> wrote:
> It can be convenient for other in-kernel drivers to reuse IIO channel
> labels. Export the iio_read_channel_label function to allow this. The
> signature is different depending on where we are calling it from, so
> the meat is moved to do_iio_read_channel_label.
>
> Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxxx>
Seems like a useful addition to me. I'm not 100% what path this will
take so if it goes via HWMON.
Acked-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
It may be messy and need an immutable branch however. I haven't
checked for churn in this code yet.
> ---
>
> drivers/iio/iio_core.h | 4 ++++
> drivers/iio/industrialio-core.c | 23 ++++++++++++++---------
> drivers/iio/inkern.c | 6 ++++++
> include/linux/iio/consumer.h | 10 ++++++++++
> 4 files changed, 34 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
> index 1a38b1915e7a..b7d5f4f0fada 100644
> --- a/drivers/iio/iio_core.h
> +++ b/drivers/iio/iio_core.h
> @@ -34,6 +34,10 @@ void iio_device_ioctl_handler_register(struct iio_dev *indio_dev,
> struct iio_ioctl_handler *h);
> void iio_device_ioctl_handler_unregister(struct iio_ioctl_handler *h);
>
> +ssize_t do_iio_read_channel_label(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *c,
> + char *buf);
> +
> int __iio_add_chan_devattr(const char *postfix,
> struct iio_chan_spec const *chan,
> ssize_t (*func)(struct device *dev,
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 2f185b386949..0f6cda7ffe45 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -727,22 +727,27 @@ 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)
> +ssize_t do_iio_read_channel_label(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *c,
> + 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);
> + return indio_dev->info->read_label(indio_dev, c, buf);
>
> - if (this_attr->c->extend_name)
> - return sysfs_emit(buf, "%s\n", this_attr->c->extend_name);
> + if (c->extend_name)
> + return sysfs_emit(buf, "%s\n", c->extend_name);
>
> return -EINVAL;
> }
>
> +static ssize_t iio_read_channel_label(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + return do_iio_read_channel_label(dev_to_iio_dev(dev),
> + to_iio_dev_attr(attr)->c, buf);
> +}
> +
> static ssize_t iio_read_channel_info(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
> index 39cf26d69d17..9f484c94bc6e 100644
> --- a/drivers/iio/inkern.c
> +++ b/drivers/iio/inkern.c
> @@ -1010,3 +1010,9 @@ ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
> chan->channel, buf, len);
> }
> EXPORT_SYMBOL_GPL(iio_write_channel_ext_info);
> +
> +ssize_t iio_read_channel_label(struct iio_channel *chan, char *buf)
> +{
> + return do_iio_read_channel_label(chan->indio_dev, chan->channel, buf);
> +}
> +EXPORT_SYMBOL_GPL(iio_read_channel_label);
> diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
> index e9910b41d48e..333d1d8ccb37 100644
> --- a/include/linux/iio/consumer.h
> +++ b/include/linux/iio/consumer.h
> @@ -441,4 +441,14 @@ ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
> ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
> const char *buf, size_t len);
>
> +/**
> + * iio_read_channel_label() - read label for a given channel
> + * @chan: The channel being queried.
> + * @buf: Where to store the attribute value. Assumed to hold
> + * at least PAGE_SIZE bytes.
> + *
> + * Returns the number of bytes written to buf, or an error code.
> + */
> +ssize_t iio_read_channel_label(struct iio_channel *chan, char *buf);
> +
> #endif
