On 04/04/2017 19:12, Fabio Estevam wrote:
On Tue, Apr 4, 2017 at 8:38 AM, Fabio Estevam festevam@gmail.com wrote:
I have the following SSI1 values (with the original 4.1-rc5 + pictrl patch):
# cat /sys/kernel/debug/regmap/2028000.ssi/registers 00: 00000200 04: 00000000 10: 0000105b
Bits 6-5 (I2S_MODE) of register SCR are 10 of register SCR, which means I2S slave mode.
The MX6 Reference Manual states:
"In I2S slave mode(SSI_SCR[6:5]=10), the following settings are internally overridden by the hardware:
Normal mode is selected (SSI_SCR[3]=0) Tx frame sync length set to one-bit-long-frame (SSI_STCR[1]=1) Rx frame sync length set to one-bit-long-frame (SSI_SRCR[1]=1)"
so I tried not to use the the one-bit-long-frame (since ENGcm06222 is about bit length frame sync) override and changed it to I2S normal mode instead:
--- a/sound/soc/fsl/fsl_ssi.c +++ b/sound/soc/fsl/fsl_ssi.c @@ -973,7 +973,7 @@ static int _fsl_ssi_set_dai_fmt(struct device *dev, ssi_private->i2s_mode |= CCSR_SSI_SCR_I2S_MODE_MASTER; break; case SND_SOC_DAIFMT_CBM_CFM:
ssi_private->i2s_mode |= CCSR_SSI_SCR_I2S_MODE_SLAVE;
ssi_private->i2s_mode |= CCSR_SSI_SCR_I2S_MODE_NORMAL; break; default: return -EINVAL;and I do not get the channel swap anymore.
In what cases could we safely switch to I2S normal mode?
SCR bit 3 (NET) is also set, so you should be in network mode with a long frame sync. In fact, you can entirely simulate a I2S behavior using Network mode. you should just be careful about the way everything is configured (eg. place of samples in the stream)
Also, I just read the ENGcm06222 chip errata. http://www.nxp.com/assets/documents/data/en/errata/IMX35CE.pdf
and I don't understand why it affects us in this case. - you are slave in your case and you don't send the Fsync - it talk about writing EN and TE in the same frame (so with less than 1/44100s). => Writing the register at once is simply a good way to be sure it is effective... except if it takes more than a frame to configure the whole stuff. And I also don't understand how all of this could have work so long before in "Capture, then later, playback scenario", were TE is set very long after EN...
Arnaud
Thanks