nitpicking ahead
> There are times when a trigger consumer shouldn't be allowed to change
> triggers after intialization.
> This is useful with use of callback buffers pushing ADC data back to the
> trigger providers iio device.
not clear, grammar
>
> Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
> ---
>
> Changes from v1:
> * use bool instead of int for trig_readonly property
>
> drivers/iio/industrialio-trigger.c | 20 ++++++++++++++++++++
> include/linux/iio/iio.h | 2 ++
> include/linux/iio/trigger.h | 9 +++++++++
> 3 files changed, 31 insertions(+)
>
> diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
> index 7ad82fdd3e5b..a3ae3873f998 100644
> --- a/drivers/iio/industrialio-trigger.c
> +++ b/drivers/iio/industrialio-trigger.c
> @@ -119,6 +119,22 @@ void iio_trigger_unregister(struct iio_trigger *trig_info)
> }
> EXPORT_SYMBOL(iio_trigger_unregister);
>
> +int iio_trigger_set_immutable(struct iio_dev *dst, struct iio_trigger *trig)
dst is not an obvious choice for the iio_dev variable, how about
indio_dev?
> +{
> + if (!dst || !trig)
> + return -EINVAL;
> +
> + mutex_lock(&dst->mlock);
> + WARN_ON(dst->trig_readonly);
> +
> + dst->trig = iio_trigger_get(trig);
> + dst->trig_readonly = true;
> + mutex_unlock(&dst->mlock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(iio_trigger_set_immutable);
> +
> /* Search for trigger by name, assuming iio_trigger_list_lock held */
> static struct iio_trigger *__iio_trigger_find_by_name(const char *name)
> {
> @@ -384,6 +400,10 @@ static ssize_t iio_trigger_write_current(struct device *dev,
> mutex_unlock(&indio_dev->mlock);
> return -EBUSY;
> }
> + if (indio_dev->trig_readonly) {
> + mutex_unlock(&indio_dev->mlock);
> + return -EPERM;
> + }
> mutex_unlock(&indio_dev->mlock);
>
> trig = iio_trigger_find_by_name(buf, len);
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index 854e2dad1e0d..786952cd509f 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -483,6 +483,7 @@ struct iio_buffer_setup_ops {
> * @scan_timestamp: [INTERN] set if any buffers have requested timestamp
> * @scan_index_timestamp:[INTERN] cache of the index to the timestamp
> * @trig: [INTERN] current device trigger (buffer modes)
> + * @trig_readonly [INTERN] mark the current trigger immutable
> * @pollfunc: [DRIVER] function run on trigger being received
> * @pollfunc_event: [DRIVER] function run on events trigger being received
> * @channels: [DRIVER] channel specification structure table
> @@ -523,6 +524,7 @@ struct iio_dev {
> bool scan_timestamp;
> unsigned scan_index_timestamp;
> struct iio_trigger *trig;
> + bool trig_readonly;
> struct iio_poll_func *pollfunc;
> struct iio_poll_func *pollfunc_event;
>
> diff --git a/include/linux/iio/trigger.h b/include/linux/iio/trigger.h
> index 1c9e028e0d4a..9e22284a4122 100644
> --- a/include/linux/iio/trigger.h
> +++ b/include/linux/iio/trigger.h
> @@ -132,6 +132,15 @@ int iio_trigger_register(struct iio_trigger *trig_info);
> void iio_trigger_unregister(struct iio_trigger *trig_info);
>
> /**
> + * iio_trigger_set_immutable() - set an immutable trigger on destination
> + *
> + * @dst - destination device for trigger
> + * @trig - trigger to assign to destination
> + *
> + **/
> +int iio_trigger_set_immutable(struct iio_dev *dst, struct iio_trigger *trig);
> +
> +/**
> * iio_trigger_poll() - called on a trigger occurring
> * @trig: trigger which occurred
> *
>
--
Peter Meerwald-Stadler
+43-664-2444418 (mobile)
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