Re: [PATCH] Adds dB gain to alsa-driver, alsa-lib.

[Liam Girdwood <liam.girdwood@wolfsonmicro.com>]

On Fri, 2005-12-16 at 11:27 +0100, Takashi Iwai wrote:

> 
> Err, then it's a misunderstanding.  I'm also against inclusion of
> unnecessary code in the kernel.  That is, if the dB information for
> each control is static and unchanged, it shouldn't be embedded in the
> driver.
> 

I also agree that some dB information shouldn't be in the kernel (e.g.
lookup tables), however I think it makes sense for simple controls with
a linear dB step size to be within the driver. 

I'd like to be able to do something like:-

SOC_SINGLE("Left ADC Capture Volume", WM8753_LADC, 0, 63, 0, DB(-17.25,
0.75),

This describes a control with a dB gain starting at -17.25 and in
increments of 0.75dB. The dB info could be represented in hex as
follows:-

0.75db = 0xC
1.00 db = 0x10 
-1.00 dB = 0x8010 (assuming we are using a short)

With a little extra effort the dB code could be extended to pass ALC
timeout information.

Liam



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