Re: [PATCH 2/2] iio: adc: ti-ads112c14: add continuous mode support

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 27 Jul 2026 08:45:57 -0500
David Lechner <dlechner@baylibre.com> wrote:

> On 7/26/26 8:45 PM, Jonathan Cameron wrote:
> > On Fri, 24 Jul 2026 15:13:11 -0500
> > "David Lechner (TI)" <dlechner@baylibre.com> wrote:
> >   
> >> Add support for continuous mode in the TI ADS112C14 ADC driver. In this
> >> mode the ADC itself is starting each conversion, so we add a trigger
> >> based on the DRDY interrupt to read each sample. This mode is also
> >> limited in that only one channel can be enabled at a time since the
> >> chip does not have a sequencer or simultaneous sampling capability.
> >> Continuous mode will only be used when this new trigger is the current
> >> trigger.
> >>  
> 
> ...
> 
> >> +static int ads112c14_buffer_predisable(struct iio_dev *indio_dev)
> >> +{
> >> +	struct ads112c14_data *data = iio_priv(indio_dev);
> >> +	int ret, ret2;
> >> +
> >> +	if (!ads112c14_using_drdy_trigger(indio_dev))
> >> +		return 0;
> >> +
> >> +	guard(mutex)(&data->lock);
> >> +
> >> +	ret = regmap_write(data->regmap, ADS112C14_REG_CONVERSION_CTRL,
> >> +			   ADS112C14_CONVERSION_CTRL_STOP);
> >> +	ret2 = regmap_assign_bits(data->regmap, ADS112C14_REG_DEVICE_CFG,
> >> +				  ADS112C14_DEVICE_CFG_CONV_MODE,
> >> +				  ADS112C14_DEVICE_CFG_CONV_MODE_SINGLE_SHOT);  
> > 
> > This is odd looking code. Needs comments on why we should prefer returning
> > the error for the second call over that for the first.  
> 
> It is arbitrary, I just went with first error wins.

?  Looks like second error wins to me!

> 
> Other option would be to return early since the hardware is going to
> be in a broken state anyway.
I'd go for that.

> 
> >   
> >> +	if (ret2)
> >> +		return ret2;
> >> +
> >> +	return ret;
> >> +}  
> > 
> >