Re: [PATCH] ARM: OMAP2+: timer: remove CONFIG_OMAP_32K_TIMER

[Igor Grinberg <grinberg@compulab.co.il>]

On 11/12/12 21:05, Jon Hunter wrote:
> 
> On 11/11/2012 03:16 AM, Igor Grinberg wrote:
>> On 11/08/12 18:20, Tony Lindgren wrote:
>>> * Igor Grinberg <grinberg@compulab.co.il> [121107 23:15]:
>>>> On 11/07/12 19:33, Tony Lindgren wrote:
>>>>>
>>>>> I think this should be the default for the timers as that counter
>>>>> does not stop during deeper idle states.
>>>>
>>>> Well, it is the default as you can see from the patch.
>>>> The problem is that for boards that for some reason do not have
>>>> the 32k wired and rely on MPU/GP timer source, the default will not work
>>>> and currently there is no way for board to specify which timer source
>>>> it can use.
>>>
>>> Yes. I was just wondering if we can avoid patching all the board
>>> files by doing it the other way around by introducing a new
>>> omap_gp_timer rather than renaming all the existing ones?
>>
>> Is the renaming that bad? One line per machine_desc structure?
>> Of course we can skip the renaming, but then it will be less consistent
>> and will not reflect the actual timer source used.
>> I tried to make it flexible as much as possible and self explanatory.
>> So above are my considerations, but at this point in time I don't really
>> care if we rename them or just add a new one, but we have to get rid of
>> the ugly fall back.
> 
> I am not sure if you guys disagree, but does it make sense to start
> thinking about this with regard to device-tree? With device-tree all the
> boards files will become obsolete and so we need to be able to handle
> this during boot time and not compile time.

This is understood completely, but I personally think that we should not
neglect the "still not converted to DT boards", because the conversion
takes time and involves much more effort. Also taking into account that
there are subsystems that are still not converted to DT.

Also, removing the CONFIG_OMAP_32K_TIMER _does_ get us closer to handle
the timers init during boot time.

> 
>>>
>>>> We have discussed this in San Diego (remember?) and you actually proposed
>>>> this way as a solution. Well, may be I took it a bit further than you
>>>> thought, but this is because the board code cannot know which timer source
>>>> should be used at runtime and the fall back described below, does not work.
>>>
>>> Yes thanks I agree we should get rid of that Kconfig option for sure. 
>>>
>>>>>> --- a/arch/arm/mach-omap2/board-2430sdp.c
>>>>>> +++ b/arch/arm/mach-omap2/board-2430sdp.c
>>>>>> @@ -284,6 +284,6 @@ MACHINE_START(OMAP_2430SDP, "OMAP2430 sdp2430 board")
>>>>>>  	.handle_irq	= omap2_intc_handle_irq,
>>>>>>  	.init_machine	= omap_2430sdp_init,
>>>>>>  	.init_late	= omap2430_init_late,
>>>>>> -	.timer		= &omap2_timer,
>>>>>> +	.timer		= &omap2_sync32k_timer,
>>>>>>  	.restart	= omap_prcm_restart,
>>>>>>  MACHINE_END
>>>>>> --- a/arch/arm/mach-omap2/board-3430sdp.c
>>>>>> +++ b/arch/arm/mach-omap2/board-3430sdp.c
>>>>>> @@ -596,6 +596,6 @@ MACHINE_START(OMAP_3430SDP, "OMAP3430 3430SDP board")
>>>>>>  	.handle_irq	= omap3_intc_handle_irq,
>>>>>>  	.init_machine	= omap_3430sdp_init,
>>>>>>  	.init_late	= omap3430_init_late,
>>>>>> -	.timer		= &omap3_timer,
>>>>>> +	.timer		= &omap3_sync32k_timer,
>>>>>>  	.restart	= omap_prcm_restart,
>>>>>>  MACHINE_END
>>>>> ...
>>>>>
>>>>> Can't we assume that the default timer is omap[234]_sync32k_timer to
>>>>> avoid renaming the timer entries in all the board files?
>>>>
>>>> Hmmm...
>>>> How will this work with the macros defining the sys_timer structure?
>>>> I would also not want to hide the exact timer used under the default name.
>>>
>>> Can't you just add a new sys_timer (or a new macro) for GP only setups? 
>>
>> Of course I can... but I tried to create a flexible generic code, so
>> no meter how a board will be wired, you just need to specify which timer source
>> it uses and be done with it.
> 
> If you are concerned about how a board is wired up (if the 32k is
> present), then I think that that is best handled via device-tree and we
> should query device-tree on boot to see what our options are.
> 
> What do you guys think?

Yes, but again, you can't neglect the non-DT case... at least
until you have everything converted to DT.


-- 
Regards,
Igor.