On Fri, 9 Jan 2015 12:13:04 +0200 Jyri Sarha jsarha@ti.com wrote:
On 01/08/2015 06:42 PM, Jean-Francois Moine wrote:
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.
There are 2 possible S/PDIF pins in the tda998x, and there may be many audio chips with S/PDIF outputs.
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.
In my original version, the audio-ports are a bitmap of the pins, the bit 0 being the WS used for I2S. A fully wired tda998x would have been as:
audio-ports = <0x03>, <0x04>, <0x09>, <0x11>; audio-port-names = "i2s", "spdif", "i2s", "i2s";
With the new version, it would simply become:
audio-inputs = "i2s", "spdif", "i2s", "i2s";