[U-Boot] [PATCH] mxs: i2c: Implement algorithm to set up arbitrary i2c speed

[Wolfgang Denk <wd@denx.de>]

Dear Marek Vasut,

In message <1354280910-17539-1-git-send-email-marex@denx.de> you wrote:
> This algorithm computes the values of TIMING{0,1,2} registers for the
> MX28 I2C block. This algorithm was derived by using a scope, but the
> result seems correct.

Thanks!  I like that!

...
> +	uint32_t base = ((24000000 / speed) - 38) / 2;
...
> +	return 24000000 / ((((timing0 >> 16) - 3) * 2) + 38);

But we should get rid of this magic constant.  On other i.MX systems
that would probably be MXC_HCLK ?

For iMX28, we have CONFIG_PL011_CLOCK in the board config files
instead.

Hm... grepping the source tree for 24000000 I get the feeling that
this really needs some cleanup....

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Vulcans worship peace above all.
	-- McCoy, "Return to Tomorrow", stardate 4768.3