[Letux-kernel] mcbsp 4

H. Nikolaus Schaller hns at goldelico.com
Fri Apr 28 08:44:04 CEST 2017


Hi,

> Am 28.04.2017 um 07:30 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> Hi,
> 
> here are some diffs between mcbsp4 between kernel 3.7 and 4.10:
> 
> arecord -Dhw:1,0 -fS16_LE -r8000 >/dev//null &
> 
> 
> --- mcbsp-record-3.7	2017-04-27 23:43:15.482272917 +0200
> +++ mcbsp-record-4.10	2017-04-27 23:43:15.490272917 +0200
> @@ -1,4 +1,4 @@
> -0x00: 0x00010222
> +0x00: 0xff693a7a
> 0x04: 0x00000000
> 0x08: 0x00000000
> 0x0c: 0x00000000
> @@ -16,7 +16,7 @@
> 0x3c: 0x00000000
> 0x40: 0x00000000
> 0x44: 0x00000000
> -0x48: 0x00000000
> +0x48: 0x0000000f
> 0x4c: 0x00000000
> 0x50: 0x00000000
> 0x54: 0x00000000
> @@ -38,8 +38,8 @@
> 0x94: 0x00000000
> 0x98: 0x00000000
> 0x9c: 0x00000000
> -0xa0: 0x00000010
> -0xa4: 0x00000081
> +0xa0: 0x00000000
> +0xa4: 0x000018b1
> 0xa8: 0x00000408
> 0xac: 0x00001009
> 0xb0: 0x00000808
> 
> 
> aplay -Dhw:1,0 -fS16_LE -r8000 /dev/zero  &
> 
> --- mcbsp-play-3.7	2017-04-27 23:43:15.474272916 +0200
> +++ mcbsp-play-4.10	2017-04-27 23:43:15.478272917 +0200
> @@ -1,4 +1,4 @@
> -0x00: 0x00010222
> +0x00: 0xff693a7a
> 0x04: 0x00000000
> 0x08: 0x00000000
> 0x0c: 0x00000000
> @@ -16,7 +16,7 @@
> 0x3c: 0x00000000
> 0x40: 0x00000000
> 0x44: 0x00000000
> -0x48: 0x00000000
> +0x48: 0x0000000f
> 0x4c: 0x00000000
> 0x50: 0x00000000
> 0x54: 0x00000000
> @@ -38,8 +38,8 @@
> 0x94: 0x00000000
> 0x98: 0x00000000
> 0x9c: 0x00000000
> -0xa0: 0x00000410
> -0xa4: 0x00000081
> +0xa0: 0x00000000
> +0xa4: 0x000018b1
> 0xa8: 0x00000408
> 0xac: 0x00001008
> 0xb0: 0x00000809
> 
> 
> Maybe that is an interesting starting point why mcbsp4.10 produces
> strange noises in 4.10.

That is interesting!

Maybe we have to set some (different) DT properties?

Essentially the same task could be to find out why the Si4721 is not working any more.

It responds a little to I2C commands but not reliably. Maybe, it is missing the McBSP1
clock for some operations.

And while writing this, I think there are potentially some subtle dependencies between
some McBSPs to consider.

BR,
Nikolaus

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