Re: [PATCH v5 09/10] iio: dac: add mcf54415 DAC

Hi Jonathan,

On Thu, Jun 11, 2026 at 11:48:00AM +0100, Jonathan Cameron wrote:
> On Wed, 10 Jun 2026 22:35:14 +0200
> Angelo Dureghello <[email protected]> wrote:
>
> > From: Angelo Dureghello <[email protected]>
> >
> > Add basic version of mcf54415 DAC driver. DAC is embedded in the SoC and
> > DAC configuration registers are mapped in the internal IO address space.
> >
> > The DAC accepts a 12-bit digital signal and creates a monotonic 12-bit
> > analog output varying from DAC_VREFL to DAC_VREFH. The DAC module
> > consists of a conversion unit, an output amplifier, and the associated
> > digital control blocks. Default register values for DAC_VREFL and DAC_VREFH
> > are respectively 0 and 0xfff, left untouched in this initial version.
> >
> > This initial version of the driver is minimalistic, "output raw" only, to
> > be extended in the future. DMA and external sync are disabled, default mode
> > is high speed, default format is right-justified 12-bit on 16-bit word.
> >
> > Signed-off-by: Angelo Dureghello <[email protected]>
> I'm lazy so didn't check earlier versions but assume the two bits
> of feedback from Sashiko are false positives:
> https://sashiko.dev/#/patchset/20260610-wip-stmark2-dac-v5-0-b76b83366d5c%40baylibre.com
>
> The one about clock underflow if resume fails, and then devm cleanup happens later
> is a bit nasty.
>
> I did a bit of digging and maybe it is better to just leave the clock on?
> The status dev.power.is_suspended is set to false whether or not resume succeeded
> and I believe a following suspend will not take into account that resume failed.
>
> I'm not set up to poke the combinations but it might be worth trying that.
> +CC common clk people who may immediately know what the right answer is.
>

was about testing this, there are no bus faults on read/write of registers
with clock disabled, nor warnings in dmesg on double disable.

Anyway, i see now from arch Kconfig that is not possible to have CONFIG_PM
for this specifig CPU (with MMU, PM is force-disabled), so would remove pm_ops.
Ok ?

Will fix all other things you pointyed out in v6.

> Otherwise just a few minor style comments inline.
>
> Thanks,
>
> Jonathan
>

thanks,
regards,
angelo