Re: [PATCH] iio: ad5504: Fix setting power-down state

[Jonathan Cameron <jic23@kernel.org>]

On Wed,  9 Dec 2020 11:46:49 +0100
Lars-Peter Clausen <lars@metafoo.de> wrote:

> The power-down mask of the ad5504 is actually a power-up mask. Meaning if
> a bit is set the corresponding channel is powered up and if it is not set
> the channel is powered down.
> 
> The driver currently has this the wrong way around, resulting in the
> channel being powered up when requested to be powered down and vice versa.
> 
> Fixes: 3bbbf150ffde ("staging:iio:dac:ad5504: Use strtobool for boolean values")
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> ---
> Stumbled upon this while looking at something else. It is untested, but I
> think it should be right. Alex can you double check?

I read the datasheet as saying this fix is right but will wait for
a confirmation from Alex.

Thanks,

Jonathan

> ---
>  drivers/iio/dac/ad5504.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/dac/ad5504.c b/drivers/iio/dac/ad5504.c
> index 28921b62e642..e9297c25d4ef 100644
> --- a/drivers/iio/dac/ad5504.c
> +++ b/drivers/iio/dac/ad5504.c
> @@ -187,9 +187,9 @@ static ssize_t ad5504_write_dac_powerdown(struct iio_dev *indio_dev,
>  		return ret;
>  
>  	if (pwr_down)
> -		st->pwr_down_mask |= (1 << chan->channel);
> -	else
>  		st->pwr_down_mask &= ~(1 << chan->channel);
> +	else
> +		st->pwr_down_mask |= (1 << chan->channel);
>  
>  	ret = ad5504_spi_write(st, AD5504_ADDR_CTRL,
>  				AD5504_DAC_PWRDWN_MODE(st->pwr_down_mode) |