2009/6/22 Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> > On Mon, Jun 22, 2009 at 11:08:27AM +0800, 宋宝华 wrote:>> [Please reply in-line, interspersing your new text into the message> you're replying to - it makes the discussion much easier to follow.]>> > Hi Mark,> > ***For the new DAI format> > According to I2S spec, it doesn't definite a I2S with TDM as a standard> I2S.> > http://www.nxp.com/acrobat_download/various/I2SBUS.pdf>> It's a de facto standard - several other vendors implement TDM in> exactly the same fashion. If you think about it this is a natural way> to handle TDM in I2S.>> > It looks like you are admitting this kind of timing into I2S DAI too:> > http://i3.6.cn/cvbnm/8f/3d/08/268a4560e0daa1b41d69b82419da06e1.jpg> > I think I can follow it too.>> The timing you're showing there is essentially a DSP mode with the left> and right channels alternating rather than an I2S style where the> polarity of the LRCLK signal indicates if the data transmitted at the> same time is for the left or right channel. I'd need to think about it> in slightly more detail but probably it is actually a DSP mode - with> the DSP modes only one edge of the frame sync is used so the other edge> can be anywhere else within the frame.>> > Due to my test boards, at present, the AD1938 is working in and> supporting> > TDM timing like the diagram:> > http://i3.6.cn/cvbnm/2f/e2/f2/03ae2b51c4e90749972e70bf887f926f.jpg> > It looks like DSP mode with TDM, so can I path related codes into> > SND_SOC_DAIFMT_DSP switch?>> Yes, that's DSP mode. Based on the "de facto ", I think I will merge TDM related codes intoblackfin I2S DAI directly. >>> > ***For volume controls based on stereo pairs> > Even though DAC1-DAC8 are named as DACL1,DACR1, DACL2,DACR2..., but the> > DACLx and DACRx are not always in a pair, in fact, they are independent.> As> > a codec supporting 8 channels, it can be configed into 2, 2.1, 4.1, 5.1,> > 6.1, 7.1, how to handle the pairs?>> That's fairly standard and not really a practical problem. Since> applications can address each channel of a stereo control independantly> they don't loose any control from grouping the channels together.> Having the stereo controls just makes it a bit easier when they are used> that way.> So, does it mean I need to support both single and pair since we don't knowhow users will use it? If I only create 4 pairs, how could users controlchannels not in any pair?_______________________________________________Alsa-devel mailing listAlsa-devel@xxxxxxxxxxxxxxxxxxxx://mailman.alsa-project.org/mailman/listinfo/alsa-devel
