[alsa-devel] Fwd: [PATCH 1/1] SPI : spi-pxa2xx : fix spi init of WM510205 codec via ACPI (resend)

[Charles Keepax]

On Fri, Sep 04, 2015 at 03:32:03PM +0200, Christian Hartmann wrote:
> Hi,
> 
> 
> 2015-09-02 10:13 GMT+02:00 Charles Keepax <ckeepax at opensource.wolfsonmicro.com>:
> > On Tue, Sep 01, 2015 at 11:45:31AM +0200, Christian Hartmann wrote:
> >> hi
> >>
> >> 2015-08-28 11:50 GMT+02:00 Christian Hartmann <cornogle at googlemail.com>:
> >> >
> > The chip select being wrong could well be the issue, perhaps the
> > Windows driver supports multiple chipselects where as the Linux
> > one doesn't? Do you have access to any datasheets for the SPI on
> > the AP? Alternatively you could try hacking it to use chip select
> > 0 and see if that makes the system work, seems like a long shot
> > but perhaps worth a quick go.
> >
> > Thanks,
> > Charles
> 
> ok, that was a one-shot, in effect nothing changed .
> I did set the num_chipsselect = 1 (as in vanilla kernels, so its more
> a revert) and
> changed the cs value from 1 to 0 (as a testpatch).
> as soon as the SPI device WM510205:00 is allocated,
> it tries to add the acpi_resource and in the case of the wrong SPI
> chip_select with the value 1 from the DSDT ACPI table entry, but here
> I set it again to 0.
> 
> expected : chip id register can be read, but
> nothing changed. the logs are the same in the end.
> I saw also that acpi_add_resource tries to add an irq (init with -1), but fails

Not entirely unexpected I guess, but certainly my gut feel here
is that this is a problem with the chip selects. I guess really
trying to find any available documentation on the AP/SPI and
tearing apart the SPI driver are the next steps from here. But
afraid I don't really have any great ideas for diving much
deeper. I will try to chase the Windows guys here again and see
if I can gain any clues from them but I don't really know at what
level these things are abstracted in Windows and thus if they can
really help us much.

Thanks,
Charles