Hi Eric,
On Wed, May 26, 2010 at 11:34:08AM +0200, Eric Bénard wrote:
Hi Sascha,
while trying to get a TI TLV320AIC23B codec configured as I2S master to work with an i.MX27 using the latest git kernel, I noticed there may be a problem in the slave I2S setting in imx-ssi.c
Please find two captures of the I2S bus signals :
- http://eukrea.com/tmp/initial_i2s.png : this is not an I2S signal,
both left & right are sent while Frame Sync is high (so I only get mono output)
- http://eukrea.com/tmp/i2s_slave.png : when I set I2S_MODE to 0x2 in
SCR register (scr |= SSI_SCR_NET | 0x40; at line 101 of imx-ssi.c), thus setting the SSI in "I2S slave mode", I get a real I2S signal as shown on this capture.
I understand the actual I2S configuration may work with the Freescale's PMIC but this chipset may not be fully I2S compliant and I think that the actual setting prevent real I2S codecs from being used with the i.MX.
Am I wrong here ? Shouldn't we use the I2S slave mode of the SSI instead of what is done actually ?
I just had a look at the oscilloscope. For me it seems to make no difference whether I use I2S mode or what is done in current driver. Both look like your second picture. So we can change it if there are no other objections.
Sascha