Hello Some time ago I was trying enable the A20 audio codec to work with 24bit, I think I gave one step forward, but I stopped in other point. Hope someone could help with this. Bellow is the e-mail that I sent to alsa developers list.
--- Hello, I'm working with sunxi-codec of allwinner A20 device. Currently the codec driver works only for 16bit mode, the source code can be found here: https://github.com/linux-sunxi/linux-sunxi/tree/sunxi-3.4/sound/soc/sunxi, and the A20 datasheet here: https://github.com/OLIMEX/OLINUXINO/blob/master/HARDWARE/A20-PDFs/A20%20User%20Manual%202013-03-22.pdf. Reading the allwinner A20 datasheet and doing some modifications on sunxi code I managed the codec to work in 24bit mode. However, it isn't working properly. When I play a stereo wav file using the aplay command the audio data of both channels are played mixed in only one channel and the another channel didn't plays any sound. For example, picture a wav stereo file with this samples: left right 0.5 -0.5 0.4 -0.4 0.3 -0.3 0.2 -0.2 The played sound is: left right 0.5 0.0 -0.5 0.0 0.4 0.0 -0.4 0.0 0.3 0.0 -0.3 0.0 0.2 0.0 -0.2 0.0 The A20 datasheet says: "DAC TX DATA REGISTER (TXDATA): Transmitting left, right channel sample data should be written this register one by one. The left channel sample data is first and then the right channel sample." I guess that this is related with the problem, despite the datasheet didn't notify, I think that in 16bit mode the TXDATA transmits both channels data together as the register is 32bit. I'm not familiar writing alsa driver and other alsa working concepts. I hope someone can help me with this. The diff file of sunxi-codec.c is here: http://pastebin.com/raw.php?i=SvypkVU6 I appreciate any help. Regards, Ricardo -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
