On Wed, Aug 13, 2014 at 01:16:37PM +0100, Charles Keepax wrote: > On Wed, Aug 13, 2014 at 12:38:41PM +0100, Mark Brown wrote: > > On Wed, Aug 13, 2014 at 12:08:44PM +0100, Charles Keepax wrote:
> > > Also I think the situation is more complex for example on version > > > 4.4 of the datasheet for wm8994 the WR_VAL fields appear to be in > > > register 59h. Which is not consistent with this. > > There was a change in the DC servo between revisions of the WM8994 (at > > revision E from the look of the code). This isn't documented in the > > datasheets as they only document current silicon. > Indeed, but this patch sets all revs of wm8994 to use register 57h. > The lastest version of the datasheet has this register at 59h > although some of the older versions of the datasheet (which likely > match some older revs of the chip although no way to tell which one > just from the datasheet) have it at 57h. Yes, I'm agreeing with you - I'm pointing out what Nikesh has missed (you can see this from the changelogs as well). The patch will break anything using older devices. > I think basically we need to get some clarity from hardware here > on which revs use which address and update this patch to match, > but either way it looks likely that this patch doesn't address > the whole picture. This code got rather a lot of attention...
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