From mboxrd@z Thu Jan  1 00:00:00 1970
From: Clemens Ladisch <clemens@ladisch.de>
Subject: Re: ASoC: Defining "signed integer" mixer controls?
Date: Thu, 03 Jun 2010 10:25:16 +0200
Message-ID: <4C0766EC.3090708@ladisch.de>
References: <hu6v9i$v43$1@dough.gmane.org>
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To: Stuart Longland <redhatter@gentoo.org>
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Stuart Longland wrote:
> /* ADC PGA gain volumes. From 0 to 59.5 dB in 0.5 dB steps */
> static DECLARE_TLV_DB_MINMAX(adc_tlv, 0, 0);

The comment is wrong, this control goes from 0 to 0 dB.

> 	SOC_DOUBLE_R_TLV("PCM Playback Volume",
> 			 AIC3204_LDACVOL, AIC3204_RDACVOL,
> 			 0, 127, 0, dac_tlv),
> 
> However; it treats the bitfield as unsigned, which is wrong in this
> case.  The bitfield is a signed integer in two's complement format.  How
> do I convince ALSA that these integers have a sign bit?

ALSA's controls use signed values, it's the SOC_ macros that assume
bitfields.  You should be able to define a control with your own
callbacks like in a non-ASoC driver.


Regards,
Clemens