[alsa-devel] [RFC PATCH 14/14] ASoC: qcom: document apq8016 machine driver bindings

[Kenneth Westfield]

On Sat, May 02, 2015 at 05:03:07PM -0700, Kenneth Westfield wrote:
> On Thu, Apr 30, 2015 at 06:18:26PM +0100, Srinivas Kandagatla wrote:
> > This patch adds bindings for apq8016 machine driver.
> > On APQ8016 4 MI2S can be configured to different sinks like internal
> > codec/external codec, this connection is controlled via 2 iomux
> > registers.
> > 
> > +sound: sound {
> > +	compatible = "qcom,apq8016-sndcard";
> > +	reg = <0x07702000 0x4>, <0x07702004 0x4>;
> > +	reg-names = "mic-iomux", "spkr-iomux";
> > +	qcom,model = "DB410c";
> > +
> > +	/* I2S - Internal codec */
> > +	internal-dai-link at 0 {
> > +		cpu { /* PRIMARY */
> > +			sound-dai = <&lpass MI2S_PRIMARY>;
> > +		};
> > +		codec {
> > +			sound-dai = <&wcd_codec 0>;
> > +		};
> > +	};
> > +
> > +	/* External Primary or External Secondary -ADV7533 HDMI */
> > +	external-dai-link at 0 {
> > +		external;
> > +		cpu { /* QUAT */
> > +			sound-dai = <&lpass MI2S_QUATERNARY>;
> > +		};
> > +		codec {
> > +			sound-dai = <&adv_bridge 0>;
> > +		};
> > +	};
> > +};
> 
> OK, although I will need to double-check this with the spec, it seems
> (from the patches) that there are 4 I2S ports, 2 of which are being
> used.  Usually, multi-channel audio is sent to the primary dai (which
> is MI2S), which then gets sent to the other ports by HW.  If that holds
> true for this SOC, then the external cpu dai should be labelled I2S,
> not MI2S.  If not, then both should be labelled as I2S (and the DAI
> channel constraints should be reduced to 1-2).
> 
> Looking at patch 12, the internal DAI is labelled Headset and the
> external DAI is labelled HDMI.  I will check the spec to see if the QUAT
> I2S port can handle multi-channel.

Are you planning on supporting multi-channel audio playback on HDMI, or
just stereo/mono?

-- 
Kenneth Westfield
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, 
a Linux Foundation Collaborative Project