[alsa-devel] [PATCH 5/7] ASoC: TWL4030: Helper to check chip default registers

Liam Girdwood lrg at slimlogic.co.uk
Tue May 25 15:09:56 CEST 2010

On Tue, 2010-05-25 at 15:20 +0300, Peter Ujfalusi wrote:
> > 
> > Is this purely for information/debug purposes ?
> Yes, the driver support twl4030, twl5030, twl5031, tps*something* chips.
> If someone, who have access to those chips, and in doubt, can check it.

So it's more a debug aid.

> > Why do we need to check default vales at init(). Is there another driver
> > changing the audio codec registers ?
> This driver is going to change it.
> It is also possible that the bootloader changed them (startup tone?).

Yeah, that's what I thought. In the past I've always forced the CODEC
registers to their default values during probe(). Very handy if the
driver is a module and you are recovering from a buggy state.

> So it is not really bulletproof, but at least it helped me to find out the the 
> ARXR2_APGA_CTL register does not have the reset value, which it supposed to 
> have.
> Well, I can remove it, but I thought that it is a nice touch ;)

It's nice ;) But maybe we should reset the default values at probe() to
be sure.



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