Subject: Re: i2c-mpc clocking scheme

From: Andre Schwarz <[email-masked]>
Date: Thu, 27 Nov 2008 16:43:45 +0100

Timur Tabi schrieb:
> On Thu, Nov 27, 2008 at 9:00 AM, Andre Schwarz
> <[email-masked]> wrote:
>   
>> All,
>>
>> is anybody working on some improvements regarding configurable I2C
>> frequency inside the i2c-mpc driver ?
>>
>> If not - would anybody be intersted in getting this done, i.e.
>> configurable via device tree ?
>>     
>
> Maybe I'm missing something, but U-Boot configures the I2C bus speed.
> It does this because the algorithm is specific to the SOC itself.  For
> example, the 8544 is different from the 8548.  It would be a mess to
> duplicate this code in the kernel.
>
>   
You're right regarding U-Boot, but the i2c-mpc driver overwrites the
"frequency divider register" on all chips.

I'm not happy with a fixed 0x3f @ MPC5200 which results in 65kHz ... :-(

Have a look at line 163 in drivers/i2c/busses/i2c-mpc.c

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