[PATCH 1/2] I2C: Set I2C timing registers for mxs-i2c

Wolfram Sang w.sang at pengutronix.de
Mon Apr 30 16:27:42 EDT 2012


> > > > > This sets the bus to run at 400kHz, prior to this,
> > > > > the bus frequency was undefined.
> > > > 
> > > > Not exactly. The default values let it run at 100kHz.
> > > 
> > > Have you tried dumping the default values and comparing it with the
> > > values for 100kHz in the manual?
> > 
> > Yes, sure. Doesn't it work for you? I just rechecked and the values are
> > okay. That being said, if you make it configurable for 400kHz, it would
> > in deed be better to rewrite the values for 100kHz, too.
> 
> They were different for me ... did you configure the i2c bus in your bootloader 
> possibly? Those values might have been written there since then ... I didn't run 
> i2c in u-boot before booting linux.

Nope, no I2C involved in the bootloader at all. Do you get the correct
values after soft-resetting the device?

It doesn't really matter, though. Just reinit them to the proper values
depending on the user setting.

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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