[PATCH v14 01/17] counter: 104-quad-8: Return error when invalid mode during ceiling_write

[Jonathan Cameron]

On Tue,  3 Aug 2021 21:06:11 +0900
William Breathitt Gray <vilhelm.gray at gmail.com> wrote:

> The 104-QUAD-8 only has two count modes where a ceiling value makes
> sense: Range Limit and Modulo-N. Outside of these two modes, setting a
> ceiling value is an invalid operation -- so let's report it as such by
> returning -EINVAL.
> 
> Fixes: fc069262261c ("counter: 104-quad-8: Add lock guards - generic interface")
> Acked-by: Syed Nayyar Waris <syednwaris at gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray at gmail.com>
Applied to the togreg branch of iio.git and pushed out as testing for 0-day to have
fun.

As an aside, I got the warning:
  CHECK   drivers/counter/104-quad-8.c
drivers/counter/104-quad-8.c:58: warning: Function parameter or member 'lock' not described in 'quad8'

Which might be nice to clean up, but has nothing much to do with this patch.

J

> ---
>  drivers/counter/104-quad-8.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 09a9a77cce06..81f9642777fb 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -715,12 +715,13 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
>  	case 1:
>  	case 3:
>  		quad8_preset_register_set(priv, count->id, ceiling);
> -		break;
> +		mutex_unlock(&priv->lock);
> +		return len;
>  	}
>  
>  	mutex_unlock(&priv->lock);
>  
> -	return len;
> +	return -EINVAL;
>  }
>  
>  static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,