On 5/31/16, 12:10 PM, "Caleb Crome" <caleb@xxxxxxxxx> wrote: >On Tue, May 31, 2016 at 9:53 AM, Mark Brown <broonie@xxxxxxxxxx> wrote: >> >> On Tue, May 17, 2016 at 04:43:33PM -0700, Nicolin Chen wrote: >> >> > In this case, would it be more appropriate to create one single DAI >> > with channels_max = 4 over here? >> >> Yes. >> >> > Another question is for its TDM support. This chip outputs 4-channel >> > data on two data output pins (SDOUT1 and SDOUT2) as normal mode; it >> > outputs 4-channel data on one data output pin (SDOUT1) as TDM mode. >> > However, the mode selection for a 4-channel recording should depend >> > on the hardware design: whether the SDOUT2 is connected or not. So >> > I am wondering if there is a common way or existing way to indicate >> > this hardware design. Or just by simply defining a new DT property? >> >> That's a really rare thing to have as an option, most things either do >> TDM or parallel data signals but not both. > > >Interesting comment. While I'm sure that's true for the moment, >microphone arrays are changing this quickly. I fall into the oddball >category that the main chips I use are the TLV320AIC34 and CS53L30, >and both of them can switch between TDM mode or dual I2S mode for 4 >channel support. > >Since I need to get many channels on board, and SoCs (except for TI) >rarely have enough parallel I2S ports for mic arrays, I opt for TDM >mode often. > >If you're using the CS53L30, chances are high that you're building a >mic array. Then the question is, how many microphones? up to 4, you >could live with dual I2S if your chip supports it. Beyond 4, you're >almost certainly talking TDM, unless you have a TI McASP with lots of >inputs, or an XMOS part with multiple I2S interfaces. > >Of course, it's highly dependent on what the SoC supports. I would >say it's just about mandatory for the CS53L30 driver in particular to >be able to switch between TDM or I2S mode based on a DT setting >because of the huge variability of capabilities on the SoC side. A >TI McBSP could support multiple I2S busses, but a freescale SSI must >use TDM mode. > >-Caleb For this device you are using either I2S or TDM, therefore, it will depend on the capabilities of the SoC (hence the hardware design). This will not require a DT property since it is configured by the cs53l30_set_dai_fmt callback. As Calib mentioned, you will have to use TDM if you are using greater than channels up to 16 channels for a mic array. > > > >> >> >> _______________________________________________ >> Alsa-devel mailing list >> Alsa-devel@xxxxxxxxxxxxxxxx >> >>https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.alsa-2Dprojec >>t.org_mailman_listinfo_alsa-2Ddevel&d=DQIBaQ&c=O3LcjD-V2Iepl5V0N1424A&r=N >>JtNI3T_InLOY17xIGk4jdUC7XljFdoy6miaxhGHOOI&m=Qrzd24GLzVm_xD3O3sFLrdCF9bUr >>dZ_DqkhoIuAy6b0&s=szG5oWmXcuMj-OEhja5V7GMcXXMCfLn9ia0maAr8YG8&e= >> _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
