linux-kernel - Re: [PATCH 01/26] ARM: OMAP: dmtimer: Remove setting of clk parent indirectly through platform hook

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Message-ID: <536AAEEC.5090508@ti.com>
Date:	Wed, 7 May 2014 17:08:44 -0500
From:	Joel Fernandes <joelf@...com>
To:	Tony Lindgren <tony@...mide.com>
CC:	Linux OMAP List <linux-omap@...r.kernel.org>,
	Linux ARM Kernel List <linux-arm-kernel@...ts.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 01/26] ARM: OMAP: dmtimer: Remove setting of clk parent
 indirectly through platform hook

On 05/07/2014 05:04 PM, Tony Lindgren wrote:
> * Joel Fernandes <joelf@...com> [140507 14:44]:
>> On 05/07/2014 10:19 AM, Tony Lindgren wrote:
>>> * Joel Fernandes <joelf@...com> [140424 14:44]:
>>>> There is a platform specific hook just for OMAP1 to set its clk parent.  Remove
>>>> this hook and have OMAP1 set its parent in omap1_dm_timer_init.  If OMAP1 is
>>>> ever migrated to clock framework, the correct way to do this would be through
>>>> clk_set_parent like other platforms.
>>>>
>>>> Signed-off-by: Joel Fernandes <joelf@...com>
>>>> ---
>>>>  arch/arm/mach-omap1/timer.c                |    8 +++++++-
>>>>  arch/arm/plat-omap/dmtimer.c               |    8 +++-----
>>>>  include/linux/platform_data/dmtimer-omap.h |    2 --
>>>>  3 files changed, 10 insertions(+), 8 deletions(-)
>>>>
>>>> diff --git a/arch/arm/mach-omap1/timer.c b/arch/arm/mach-omap1/timer.c
>>>> index bde7a35..4b9c604 100644
>>>> --- a/arch/arm/mach-omap1/timer.c
>>>> +++ b/arch/arm/mach-omap1/timer.c
>>>> @@ -140,7 +140,13 @@ static int __init omap1_dm_timer_init(void)
>>>>  			goto err_free_pdata;
>>>>  		}
>>>>  
>>>> -		pdata->set_timer_src = omap1_dm_timer_set_src;
>>>> +		/*
>>>> +		 * Since OMAP1 doesn't support clock framework, set timer clock
>>>> +		 * source to 32KHz here instead of expecting it to be set by
>>>> +		 * dmtimer code.
>>>> +		 */
>>>> +		omap1_dm_timer_set_src(pdev, 0x01);
>>>> +
>>>>  		pdata->timer_capability = OMAP_TIMER_ALWON |
>>>>  				OMAP_TIMER_NEEDS_RESET | OMAP_TIMER_HAS_DSP_IRQ;
>>>>  
>>>
>>> This does not sound right, omap1 does support clock framework just fine.
>>> It is not using the common clock framework though.
>>>
>>> This breaks omap_dm_timer_set_source() for sure. Setting the source
>>> during init is not a right solution here. Probably best to keep the
>>> pdata hook around, drivers can support pdata and DT data together
>>> just fine.
>>
>> Actually pdata hook in this case is used only in 1 place, and is OMAP1
>> specific so I felt its better to clean it up.
>>
>> Can you elaborate a bit more on why it breaks? I have no way of testing
>> OMAP1 without hardware.
>>
>> What difference is it to set MOD_CONF_CTRL_1 in omap1's
>> arch_initcall(omap1_dm_timer_init)  versus doing so later?
> 
> You're making a driver behave in a different way for omap1
> compared to omap2+ where selecting the clock source won't work
> for omap1.

Ok, I'll drop this patch and leave the hook as-is. Thanks.

Regards,
-Joel

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