Re: [PATCH] iio: 104-quad-8: Fix active level mismatch for the preset enable option

[Jonathan Cameron <jic23@kernel.org>]

On 29/11/16 15:51, William Breathitt Gray wrote:
> The set_to_preset_on_index sysfs attribute provides a boolean
> configuration option to enable a preset operation on the respective
> channel's counter when Index occurs. However, the corresponding
> configuration bit on the Input/Output Control register must be set low
> to enable the preset operation.
> 
> This patch inverts the internal driver boolean logic exposed via the
> set_to_preset_on_index attribute in order to correctly configure the
> device which expects an active low bit.
> 
> Fixes: 28e5d3bb0325 ("iio: 104-quad-8: Add IIO support for the ACCES 104-QUAD-8")
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied to the fixes-togreg-post-rc1 branch and marked for stable.

Thanks,

Jonathan
> ---
>  drivers/iio/counter/104-quad-8.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/counter/104-quad-8.c b/drivers/iio/counter/104-quad-8.c
> index 2d2ee35..9847221 100644
> --- a/drivers/iio/counter/104-quad-8.c
> +++ b/drivers/iio/counter/104-quad-8.c
> @@ -233,7 +233,7 @@ static ssize_t quad8_read_set_to_preset_on_index(struct iio_dev *indio_dev,
>  	const struct quad8_iio *const priv = iio_priv(indio_dev);
>  
>  	return snprintf(buf, PAGE_SIZE, "%u\n",
> -		priv->preset_enable[chan->channel]);
> +		!priv->preset_enable[chan->channel]);
>  }
>  
>  static ssize_t quad8_write_set_to_preset_on_index(struct iio_dev *indio_dev,
> @@ -250,6 +250,9 @@ static ssize_t quad8_write_set_to_preset_on_index(struct iio_dev *indio_dev,
>  	if (ret)
>  		return ret;
>  
> +	/* Preset enable is active low in Input/Output Control register */
> +	preset_enable = !preset_enable;
> +
>  	priv->preset_enable[chan->channel] = preset_enable;
>  
>  	ior_cfg = priv->ab_enable[chan->channel] |
>