Re: [PATCH 1/2] staging:iio: Make write_event_value callback optional

[Jonathan Cameron <jic23@cam.ac.uk>]

On 10/26/11 13:01, Lars-Peter Clausen wrote:
> Some devices have fixed thresholds which can not be modified so make the
> write_event_value callback optional, so the drivers for these devices do not
> have to implement a boilerplate no-op callback.
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
> ---
>  drivers/staging/iio/industrialio-core.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/staging/iio/industrialio-core.c b/drivers/staging/iio/industrialio-core.c
> index cfa4fcb..d2eea07 100644
> --- a/drivers/staging/iio/industrialio-core.c
> +++ b/drivers/staging/iio/industrialio-core.c
> @@ -782,6 +782,9 @@ static ssize_t iio_ev_value_store(struct device *dev,
>  	unsigned long val;
>  	int ret;
>  
> +	if (!indio_dev->info->write_event_value)
> +		return -EINVAL;
> +
>  	ret = strict_strtoul(buf, 10, &val);
>  	if (ret)
>  		return ret;