Re: [PATCH v2 5/6] staging: iio: ad9832: convert to iio channels and ext_info attrs

[Tomas Borquez]

On Wed, Dec 31, 2025 at 12:55:50AM +0200, Andy Shevchenko wrote:
> On Tue, Dec 30, 2025 at 10:35 PM Tomas Borquez <tomasborquez13@xxxxxxxxx> wrote:
> >
> > Convert ad9832 from sysfs attributes to standard channel interface
> > using a single IIO_ALTCURRENT channel with ext_info attributes, as this
> > device is a current source DAC with one output.

...

> > -static int ad9832_write_frequency(struct ad9832_state *st,
> > -                                 unsigned int addr, unsigned long fout)
> > +static ssize_t ad9832_write_frequency(struct iio_dev *indio_dev,
> > +                                     uintptr_t private,
> 
> Torvalds said that uintptr_t shouldn't be used in the Linux kernel,
> the unsigned long suffice and enough. Why do we need it here?

Copied it from the definition of iio_chan_spec_ext_info:

struct iio_chan_spec_ext_info {
	const char *name;
	enum iio_shared_by shared;
	ssize_t (*read)(struct iio_dev *, uintptr_t private,
			struct iio_chan_spec const *, char *buf);
	ssize_t (*write)(struct iio_dev *, uintptr_t private,
			 struct iio_chan_spec const *, const char *buf,
			 size_t len);
	uintptr_t private;
};

But can change it

> 
> > +static IIO_DEVICE_ATTR(out_altcurrent0_frequency_symbol, 0644,
> > +                      ad9832_show, ad9832_store, AD9832_FREQ_SYM);
> > +static IIO_DEVICE_ATTR(out_altcurrent0_phase_symbol, 0644,
> > +                      ad9832_show, ad9832_store, AD9832_PHASE_SYM);
> > +static IIO_DEVICE_ATTR(out_altcurrent0_enable, 0644,
> > +                      ad9832_show, ad9832_store, AD9832_OUTPUT_EN);
> 
> Why not IIO_DEVICE_ATTR_RW()?

Not any good reason just didn't know it existed.

> ...
> 
> > +       &iio_dev_attr_out_altcurrent0_frequency_symbol.dev_attr.attr,
> > +       &iio_dev_attr_out_altcurrent0_phase_symbol.dev_attr.attr,
> > +       &iio_dev_attr_out_altcurrent0_enable.dev_attr.attr,
> > +       &iio_dev_attr_out_altcurrent0_pincontrol_en.dev_attr.attr,
> >         NULL,
> 
> At some point we may also drop the comma in the terminator entry.

Will remove it as part of V3

> -- 
> With Best Regards,
> Andy Shevchenko