[alsa-devel] [PATCH] ASoC: tlv320dac33: Control for line output gain

Peter Ujfalusi peter.ujfalusi at nokia.com
Wed Oct 13 10:40:26 CEST 2010

On Wednesday 13 October 2010 11:14:03 ext Mark Brown wrote:
> On Wed, Oct 13, 2010 at 11:08:18AM +0300, Peter Ujfalusi wrote:
> > +/* L/R Line Output Gain */
> > +static const char *lr_lineout_gain_texts[] = {
> > +	"Line 0.25V/V DAC 1V/V", "Line 0.5V/V DAC 2V/V",
> > +	"Line 1V/V DAC 4V/V", "Line 2V/V DAC 8V/V",
> > +};
> I'm having a hard time parsing what these actually mean so I'm guessing
> users are going to have trouble also - is there anything that could be
> done to make things clearer?

In the documentation these gains are described like that (0.25V.V / 1V/V), and I 
wanted to use the same in the enum elements, but what about:

/* L/R Line Output Gain */
static const char *lr_lineout_gain_texts[] = {
       "Line -12dB DAC 0dB", "Line -6dB DAC 6dB",
       "Line 0dB DAC 12dB", "Line 6dB DAC 18dB",

Value 0 in the registers mean:
linein-to-lineout gain 0.25V/V (-12dB)
dac-to-lineout gain 1V/V (0dB)

Value 1 in the registers mean:
linein-to-lineout gain 0.5V/V (-6dB)
dac-to-lineout gain 2V/V (6dB)

What do you think?


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