Re: [PATCH 2/2] iio: dac: ltc2688: use the auto lock API

["Nuno Sá" <noname.nuno@gmail.com>]

On Sat, 2025-09-27 at 18:56 +0100, Jonathan Cameron wrote:
> On Tue, 23 Sep 2025 09:41:48 +0100
> Nuno Sá via B4 Relay <devnull+nuno.sa.analog.com@kernel.org> wrote:
> 
> > From: Nuno Sá <nuno.sa@analog.com>
> > 
> > Make use of the cleanup API so that we can simplify some code paths.
> > 
> > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> > ---
> >  drivers/iio/dac/ltc2688.c | 24 ++++++++++--------------
> 
> This enables a few related simplifications that should be in this patch as well.

Yes, both make sense.

- Nuno Sá
> 
> >  static int ltc2688_dac_code_read(struct ltc2688_state *st, u32 chan, u32 input,
> > @@ -236,15 +234,15 @@ static int ltc2688_dac_code_read(struct ltc2688_state *st,
> > u32 chan, u32 input,
> >  	struct ltc2688_chan *c = &st->channels[chan];
> >  	int ret;
> >  
> > -	mutex_lock(&st->lock);
> > +	guard(mutex)(&st->lock);
> >  	ret = regmap_update_bits(st->regmap, LTC2688_CMD_A_B_SELECT, BIT(chan),
> >  				 input << chan);
> >  	if (ret)
> > -		goto out_unlock;
> > +		return ret;
> >  
> >  	ret = regmap_read(st->regmap, LTC2688_CMD_CH_CODE(chan), code);
> > -out_unlock:
> > -	mutex_unlock(&st->lock);
> > +	if (ret)
> > +		return ret;
> >  
> >  	if (!c->toggle_chan && input == LTC2688_INPUT_B)
> >  		*code = FIELD_GET(LTC2688_DITHER_RAW_MASK, *code);
> 
> There is a return ret later in this function that can be return 0;
> 
> > @@ -359,15 +357,13 @@ static ssize_t ltc2688_dither_toggle_set(struct iio_dev
> > *indio_dev,
> >  	if (ret)
> >  		return ret;
> >  
> > -	mutex_lock(&st->lock);
> > +	guard(mutex)(&st->lock);
> >  	ret = regmap_update_bits(st->regmap, LTC2688_CMD_TOGGLE_DITHER_EN,
> >  				 BIT(chan->channel), en << chan->channel);
> >  	if (ret)
> > -		goto out_unlock;
> > +		return ret;
> >  
> >  	c->mode = en ? LTC2688_MODE_DITHER_TOGGLE : LTC2688_MODE_DEFAULT;
> > -out_unlock:
> > -	mutex_unlock(&st->lock);
> >  
> >  	return ret ?: len;
> return len; as can't get here with non zero ret.
> 
> >  }
> > 
>