Re: Nokia N900 - audio TPA6130A2 problems

[Ivaylo Dimitrov]

Hi,

On 17.03.2016 02:49, Sebastian Reichel wrote:
> mh both, the power gpio is turned off in tpa6130a2_power(0). I guess
> if you don't see the problem during probe() everything works?
>
> I have another idea though: In opposit to the gpio, the regulator
> may also be referenced by something else/already enabled. I guess
> adding a sleep after the regulator_enable() is worth a try.
>
> Also I wonder if the same happens, if you avoid having the module
> available during boot and instead load it once everything has
> settled. That would rule out any side-effects of other modules
> being probed on the same i2c bus.


Well, I think I've figured it out - input pullups are not enabled
on i2c bus pins, in stock kernel we have:

./devmem2 0x480021BC
Value at address 0x480021BC (0x4001f1bc): 0x1180118

./devmem2 0x480021C0
Value at address 0x480021C0 (0x4001f1c0): 0x1180118

in mainline

./devmem2 0x480021BC
Value at address 0x480021BC (0xb6ff01bc): 0x1000100

./devmem2 0x480021C0
Value at address 0x480021C0 (0xb6f6d1c0): 0x1000100

I wonder how i2c devices work at all :)

Will fix the board DTS file later on an will report

Regards,
Ivo