[U-Boot] [PATCH] ARMv7: OMAP: Add init function for TWL4030 GBPR1 register

[Jonathan Solnit]

Hi Igor.

On Thu, Mar 1, 2012 at 12:41 AM, Igor Grinberg <grinberg at compulab.co.il>wrote:

> Hi Jonathan,
>
> On 02/29/12 22:52, Jonathan Solnit wrote:
> > The OMAP ROM code modifies the GBPR1 register, which can cause
>
> s/GBPR1/GPBR1/
>
> > unintended consequences.
>
> What do you mean by this?
> Can you please elaborate, what issues do you see?
> Also, why does the OMAP ROM code needs to touch the GPBR1?
>
>
For my board, when booting the OMAP3 from MMC1, GPBR1 comes up as 0x00
instead of 0x90.  The improper clock configuration causes timeouts whenever
I try to use the MADC.  In Linux, the error looks like this:

user.err kernel: twl4030_madc twl4030_madc: conversion timeout!

As for why ROM touches GPBR1, only TI can answer that.  What I've found is
that this is a known issue and re-initializing the register at start-up is
the recommended solution:

http://e2e.ti.com/support/power_management/pmu/f/43/t/762.aspx

Thanks,
Jonathan