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

Mark Brown
2015-06-25T15:56:12Z

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On Thu, Jun 25, 2015 at 04:44:07PM +0100, Charles Keepax wrote:
> On Thu, Jun 25, 2015 at 03:58:53PM +0100, Mark Brown wrote:
> > On Thu, Jun 25, 2015 at 02:18:23PM +0200, Christian Hartmann wrote:

> > > Name (_HID, "WM510205") // _HID: Hardware ID
> > > Name (_CID, "WM510205") // _CID: Compatible ID
> > > Name (_DDN, "Wolfson Microelectronics Audio WM5102")

> > Separately to the chip select discussion one thing to highlight here is
> > that for some reason the BIOS is listing the device as "WM510205" rather
> > than "WM5102" - do those extra numbers mean anything and does this mean
> > that WM50120[1-4] and possibly higher numbers are also valid?

> From my brief discussions with the Windows guys here on this
> basically those last two digits are being used to inform the
> Windows driver of use-case setup. So here it will set things up
> for whatever the Window's driver considers to be setup "5".

Yay for scalability and abstraction.

> I think from the Linux side we can safely ignore those last two
> digits. I expect that all systems of the same make and model
> would report the same last two digits but that it might change
> between models if the Windows driver is expected to something
> differently for that model.

Well, we might want to consider using this to set our platform data
instead of the machine ID if people have just been copying a smallish
set of reference designs, it might might make for a slightly smaller set
of ID tables than the machine ID based stuff does.

Due to the way ACPI ID matching works we'll also need to add every
suffix individually to the table, we're looking for complete matches not
substring matches here.

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