From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jyri Sarha Subject: Re: [PATCH v9 1/4] drm/i2c: tda998x: Add DT support for audio Date: Fri, 9 Jan 2015 12:13:04 +0200 Message-ID: <54AFA9B0.6040405@ti.com> References: <0084acea5a3475a77531d6a77483f36d3469111a.1420628786.git.moinejf@free.fr> <54AE99F5.1010404@ti.com> <20150108174257.557f7ea5@armhf> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150108174257.557f7ea5@armhf> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jean-Francois Moine Cc: Mark Brown , Russell King - ARM Linux , Dave Airlie , Andrew Jackson , alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On 01/08/2015 06:42 PM, Jean-Francois Moine wrote: > On Thu, 8 Jan 2015 16:53:41 +0200 > Jyri Sarha wrote: > >>> + - audio-ports: must contain one or two values selecting the source >>> + in the audio port. >>> + The source type is given by the corresponding entry in >>> + the audio-port-names property. >>> + >> >> This binding does not allow multi channel i2s setups with multiple i2s >> pins. It would be nice to support that in the DT binding, even if the >> code is not yet ready for it. >> >> How about having these two optional properties instead of audio-ports >> and audio-port-names: >> >> audio-port-i2s: Upto 4 values for selecting pins for i2s port >> audio-port-spdif: Value for selecting input pin for spdif port >> >> Presence of one of the properties would be mandatory and both are allowed. >> >> Sorry to notice this only now, but I have not yet looked the drm side >> changes too closely. > > From Andrew's datasheet, the TDA998x's which are handled by the tda998x > driver have only 4 input audio pins, the first two ones being either > S/PDIF or I2s, the last ones being I2S only. > AFAIK, SPDIF is always a single pin connection so only one pin needs to be selected. But i2s need for pins for full 8 channel output. > So, the DT description could be reduced to a simple list indexed by > the pin number (= DAI number) and defining the protocol type. > > Examples: > > - for the Cubox: > > audio-inputs = "i2s", "spdif"; > > - for some other board with I2S on the pins 3 and 4 only: > > audio-inputs = "none", "none", "i2s", "i2s"; > > - for a fully wired TDA9983B (no driver yet): > > audio-inputs = "i2s", "i2s", "i2s", "i2s", "spdif"; > If you want to go closer to the original paradigm, then how about defining following audio-port-names: i2s0, i2s1, i2s2, i2s3, and spdif. With this approach we could go with your original binding with only minor changes. A binding in your stereo i2s or spdif case would look like this: audio-ports = <0x04>, <0x03>; audio-port-names = "spdif", "i2s0"; A full 8 channel i2s or spdif output would look like this: audio-ports = <0x04>, <0x03>, <0x02>, <0x01>, <0x00>; audio-port-names = "spdif", "i2s0", "i2s1", "i2s2", "i2s3"; This would also indicate the channel mapping to the audio pins (i2s0 for first two channels, i2s1 for 3-4, etc.) The code could for now just look for "i2s0" and the port names for channels 3-8 could be ignored until they are needed. Best regards, Jyri -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html