[U-Boot] TI:OMAP:[PATCH 4/7] Add support for 720Mhz

Tom Tom.Rix at windriver.com
Mon Jan 25 16:03:39 CET 2010


Khasim Syed Mohammed wrote:
> On Sun, Jan 24, 2010 at 5:39 AM, Tom <Tom.Rix at windriver.com> wrote:
>> Khasim Syed Mohammed wrote:
>>> From 977856ac122e451a8de195d9f22253196572157a Mon Sep 17 00:00:00 2001
>>> From: Syed Mohammed Khasim <khasim at ti.com>
>>> Date: Tue, 12 Jan 2010 16:32:42 +0530
>>> Subject: [PATCH] Add support for 720Mhz
>>>
>>> A New API to allow setting M value to support 720Mhz
>>>
>>> Signed-off-by: Syed Mohammed Khasim <khasim at ti.com>
>>> ---
>>>  cpu/arm_cortexa8/omap3/clock.c |   21 +++++++++++++++++++++
>>>  1 files changed, 21 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/cpu/arm_cortexa8/omap3/clock.c
>>> b/cpu/arm_cortexa8/omap3/clock.c
>>> index 174c453..d67517a 100644
>>> --- a/cpu/arm_cortexa8/omap3/clock.c
>>> +++ b/cpu/arm_cortexa8/omap3/clock.c
>>> @@ -402,3 +402,24 @@ void per_clocks_enable(void)
>>>
>>>        sdelay(1000);
>>>  }
>>> +
>>> +/*
>>> + * Configure PRCM registers to get 720 Mhz
>>> + *
>>> + * NOTE: N value doesn't change, only M gets affected
>>> + */
>>> +void prcm_config_720mhz(void)
>>> +{
>> Generalize this
> Can be
>> Change the name prcm_config.
> It is not actually PRCM config, this is specific to M value for 720Mhz
> 
>> Possiblly pass in an enum for supported clk.
>>
>> Setting the omap clk is not this simple.
>> It is dependent on at least the input frequency.
> Please see the entire file, the clocks are already set for 500 Mhz
> based on all the other relevant parameters, this patch will push the
> frequency to 720 Mhz.
> 
>> I do not see where this is checked here.
>> You should rethink how this is being done.
> I think, I gave multiple tries and have also posted on this list. This
> should be the simplest and most correct way.
> 
>> Move this to the beagle board dir.
>>
> No, the register definitions and structures are not available there,
> why do you want to move this to board specific, this is generic and
> any other board can all the API to set the m value for 720 Mhz.

This change may work for Beagle revC but it will not work in general.
The cpu level is for general omap changes.  What i don't want is every
board adding there own special functions here to tweak clock parameters.
Functions like this should go in the board files.

Tom

> 
> Regards
> 
> Khasim



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