[U-Boot] [PATCH] arm: mvebu: move i2c slave disable to generic SPL code

[Baruch Siach]

Hi Stefan,

On Mon, May 28, 2018 at 12:05:43PM +0200, Stefan Roese wrote:
> On 28.05.2018 11:56, Baruch Siach wrote:
> > On Mon, May 28, 2018 at 10:20:01AM +0200, Stefan Roese wrote:
> > > On 28.05.2018 10:11, Chris Packham wrote:
> > > > On Mon, May 28, 2018 at 3:27 AM Baruch Siach <baruch at tkos.co.il> wrote:
> > > > 
> > > > > The hidden i2c slave that interferes the i2c bus is not board specific.
> > > > > All Armada 38x SoCs are affected. Move the code disabling this slave to
> > > > > generic code to make it work on all affected hardware.
> > > > 
> > > > I can't find a definition of this but the register seems to work for
> > > > kirkwood as well (not surprising since it's probably a common IP block). Is
> > > > there any chance we can find a home for this that's available to boards
> > > > that don't use SPL?
> > > 
> > > Yes, please. Can't we move this into the I2C driver instead (mvtwsi.c)?
> > > No need to use MVEBU_TWSI_BASE then.
> > 
> > The trouble is that the Turris Omnia board needs the i2c in SPL to read the
> > RAM configuration from EEPROM. But I could not get the __twsi_i2c_init()
> > routine (runs in both DM and non-DM) to be called from SPL.
> 
> Are you sure? How can you use the I2C functions of this driver, if the
> init / probe function is not called?

__twsi_i2c_init() is called from the main U-Boot image, but not from SPL as 
far as my testing shows. Clearfog doesn't use i2c from SPL, but the Turris 
board does.

baruch

> > I'm testing on (currently non-DM) 388 Clearfog Base.
> > 
> > In my testing here the hidden i2c slave interferes bus communication that runs
> > at any speed other than 100KHz. If that is not a problem for Turris Omnia I
> > can move the slave disable code to __twsi_i2c_init().
> > 
> > baruch

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