[PATCH 1/2 V3] MXS: Set I2C timing registers for mxs-i2c

Marek Vasut marex at denx.de
Mon Jun 11 06:53:17 EDT 2012


Dear Shawn Guo,

> On Sun, Jun 10, 2012 at 01:53:05PM +0200, Marek Vasut wrote:
> > > +struct mxs_i2c_speed_config {
> > > +	uint32_t	timing0;
> > > +	uint32_t	timing1;
> > > +	uint32_t	timing2;
> > > +};
> > > +
> > > +/* Timing values for the default 24MHz clock supplied into the i2c
> > > block.
> > 
> > Thinking about these further -- does anyone have any idea how these
> > numbers were derived? And possibly even formula for that?
> > 
> > And maybe we should somehow make sure the source runs on 24MHz (how?).
> 
> There is nothing about I2C clock mentioned in CLKCTRL chapter.  I just
> contacted design team and was told that I2C clock sources from APBX
> (xbus) clock and always runs at the same frequency there.

Ok, then can you please try asking them how to exactly compute the values in 
timing0-timing2 registers? So we don't have to hardcode them like it's done now?

Best regards,
Marek Vasut



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