[alsa-devel] [PATCH] ASoC: TWL4030: PM fix for output amplifiers

[Peter Ujfalusi]

On Tuesday 23 March 2010 09:05:39 Ujfalusi Peter (Nokia-D/Tampere) wrote:
> In any ways the output gains has to be handled with custom code no matter
> if the core has support for binding the volume controls to DAPM widget or
> not. The root of the problem is how the amplifiers are working:
> bit 4-5: Gain
> 0x0 - power down (mute)
> 0x1 - 6dB
> 0x2 - 0dB
> 0x3 - -6dB
> 
> I don't have separate power bit.
> I can not just invert the range.
> I need to do the following:
> If 0 is coming, than I write that (mute, power down)
> If 2, than write two
> For 1 I write 3
> For 3 I write 1
> This gives nice gain range for the user space.
> 0x0 - power down (mute)
> 0x1 - -6dB
> 0x2 - 0dB
> 0x3 - 6dB

I just wonder, would something like this work:

Instead of the custom SOC_DOUBLE_R_TLV_TWL4030, which handles the output gains:

/*
 * Gain controls tied to outputs
 * -6 dB to 6 dB in 6 dB steps (mute instead of -12)
 */
static const unsigned int output_tlv[] = {
	TLV_DB_RANGE_HEAD(4),
	0, 0, TLV_DB_SCALE_ITEM(-1200, 0,  1),
	3, 3, TLV_DB_SCALE_ITEM(-600, 0, 0),
	2, 2, TLV_DB_SCALE_ITEM(0, 0, 0),
	1, 1, TLV_DB_SCALE_ITEM(600, 0, 0),
};

SOC_DOUBLE_R_TLV("PreDriv Playback Volume",
	TWL4030_REG_PREDL_CTL, TWL4030_REG_PREDR_CTL,
	4, 3, 0, output_tvl),

I'm not sure about the tlv declaration, but is there a way to actually map the 
gain/power control in the TWL in a standard way?

-- 
Péter