Re: [PATCH v3 2/2] iio: adc: Add TI ADS1100 and ADS1000

[Lars-Peter Clausen]

On 3/2/23 05:16, Lars-Peter Clausen wrote:
> On 3/1/23 23:49, Mike Looijmans wrote:
> > > ...
> > > ...
> > >
> > > > +static int ads1100_runtime_suspend(struct device *dev)
> > > > +{
> > > > +    struct iio_dev *indio_dev = 
> > > > i2c_get_clientdata(to_i2c_client(dev));
> > > > +    struct ads1100_data *data = iio_priv(indio_dev);
> > > > +
> > > > +    ads1100_set_config_bits(data, ADS1100_CFG_SC, 
> > > > ADS1100_SINGLESHOT);
> > > > +    regulator_disable(data->reg_vdd);
> > > Wrong devm / non-devm ordering.
> >
> > Don't understand your remark, can you explain further please?
> >
> > devm / non-devm ordering would be related to the "probe" function. As 
> > far as I can tell, I'm not allocating resources after the devm calls. 
> > And the "remove" is empty.
>
> Strictly speaking we need to unregister the IIO device before 
> disabling the regulator, otherwise there is a small window where the 
> IIO device still exists, but doesn't work anymore. This is a very 
> theoretical scenario though.
>
> You are lucky :) There is a new function 
> `devm_regulator_get_enable()`[1], which will manage the 
> regulator_disable() for you. Using that will also reduce the 
> boilerplate in `probe()` a bit
>
> - Lars
>
> [1] https://lwn.net/Articles/904383/
Sorry, just saw that Andy's comment was on the suspend() function, not 
remove(). In that case there is of course no need for any devm things. 
But still a good idea to use `devm_regulator_get_enable()` in probe for 
the boiler plate.