Re: [PATCH v6 0/2] add mcf54415 DAC driver

[Angelo Dureghello]

Hi Andy,
On Wed, Jun 24, 2026 at 12:18:38AM +0300, Andy Shevchenko wrote:
> On Thu, Jun 18, 2026 at 11:04:14PM +0200, Angelo Dureghello wrote:
> > This patchset adds a minimalistic DAC driver for the NXP mcf54415/6/7/8
> > builtin DACs.
> >
> > Currently the driver enables the raw write only. Feature as dma, sync, or
> > format are not supoprted for this version.
> >
> > Additional options suppoerted by the DAC module will be added to the driver
> > later on, as needed.
> >
> > The same patchset prepares the m68k/coldfire architecture to support
> > the driver.
> >
> > Below some basic tests done on stmark2 mcf54415-based board, voltage check
> > on DAC0 and DAC1:
> >
> > ~ # cd /sys/bus/iio/devices/iio:device0/
> > /sys/bus/iio/devices/iio:device0 # ls
> > name               out_voltage_scale  uevent
> > out_voltage_raw    subsystem
> > /sys/bus/iio/devices/iio:device0 # cat name
> > mcf54415
> > /sys/bus/iio/devices/iio:device0 # echo 4095 > out_voltage_raw
> > /sys/bus/iio/devices/iio:device0 # echo 2048 > out_voltage_raw
> > /sys/bus/iio/devices/iio:device0 # echo 4096 > out_voltage_raw
> > sh: write error: Invalid argument
> > /sys/bus/iio/devices/iio:device0 # cat out_voltage_raw
> > 2048
> > /sys/bus/iio/devices/iio:device0 #
> >
> > Same behavior for /sys/bus/iio/devices/iio:device1.
> >
> > Generated a sine wave by shell script, sine shape is good.
>
> Heard a presentation (Embedded Recipes IIRC) where one tried sine and real
> sound (it was about sound DAC) was really awful. So, Can you try a bit more
> sophisticated signal?
>

sure can try some sound with this 12-bit, but don't think is possible now
with only raw output. My idea is with further patches, once ColdFire DMA
is fixed, to extend the driver and be able to sample higher frequencies.

> --
> With Best Regards,
> Andy Shevchenko
>
>
Regards,
angelo