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

From: Jonathan Cameron <jic23@kernel.org>
To: Alexandru Ardelean <ardeleanalex@gmail.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
	Alexandru Ardelean <alexandru.ardelean@analog.com>,
	linux-iio <linux-iio@vger.kernel.org>
Subject: Re: [PATCH] iio: ad5504: Fix setting power-down state
Date: Tue, 29 Dec 2020 18:28:43 +0000	[thread overview]
Message-ID: <20201229182843.0086fc88@archlinux> (raw)
In-Reply-To: <CA+U=DspaoNjJGei+kyV4L+MzvYqJy08LdsGnf0y6uHr85PbD5g@mail.gmail.com>

On Mon, 14 Dec 2020 09:23:20 +0200
Alexandru Ardelean <ardeleanalex@gmail.com> wrote:

> On Sun, Dec 13, 2020 at 8:59 PM Jonathan Cameron <jic23@kernel.org> wrote:
> >
> > 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.  
> 
> Oh.
> I see why the initial confusion existed.
> Was confused a bit myself.
> The thermal shutdown follows the initial/unchanged logic.
> While the actual powerdown channel bits are inverted.
> 
> Acked-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Applied to the fixes-togreg branch of iio.git and marked for
stable.

Thanks,

Jonathan

> 
> 
> >
> > 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) |  
> >