Re: [PATCH 2/2] iio: dac: mcp47a1: add support for new device

From: Joshua Crofts

Date: Sat Jul 25 2026 - 06:22:21 EST


On Sat, 25 Jul 2026 00:14:17 +0100
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> Given the really small number of registers, regmap does seem like
> it might be overkill

My thought was that regmap is preferred over i2c_smbus_* functions,
but that is a simple enough move.

...

> > + /*
> > + * This is a volatile DAC which doesn't have an ID register, instead
> > + * the value register is set to 0x20 every Power-on-Reset (table 4-1).
> > + * Any other read value at startup could indicate that the device is
> > + * damaged etc.
>
> or some earlier software wrote it and the all the regulators are stubs
> provided as they can't be turned off by software.
>
> I'd drop this test - it is a bit too flakey as a way to tell the chip
> is there and working.

Yeah, fair enough, there's a reason why it just reports it as dev_info().

--
Kind regards,
Joshua Crofts