RE: [PATCH] OMAP3: USBHOST: Fix prcm interrupt handler

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>-----Original Message-----
>From: Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx]
>Sent: Friday, July 17, 2009 6:32 PM
>To: Pandita, Vikram
>Cc: linux-omap@xxxxxxxxxxxxxxx
>Subject: Re: [PATCH] OMAP3: USBHOST: Fix prcm interrupt handler
>
>Vikram Pandita <vikram.pandita@xxxxxx> writes:
>
>> For clearing the PM_WKST of USBHOST domain, two fclocks need
>> to be enabled: HOST1 and HOST2
>>
>> Current code just enables HOST1 fclock and thus not clearing the
>> Wake status of usbhost domain correctly
>
>I think the changelog needs a little more detail.  Something like:
>
>USBHOST module has 2 fclocks (for HOST1 and HOST2), only one iclock
>and only a single bit in the WKST register to indicate a wakeup event.
>
>Because of the single WKST bit, we cannot know whether a wakeup event
>was on HOST1 or HOST2, so enable both fclocks before clearing the
>wakeup event to ensure both hosts can properly clear the event.
>
>And shortlog (subject) should be:
>
>OMAP3: PM: USBHOST: clear wakeup events on both hosts

Ok will send v2 patch with this short log and comments.

>
>> Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
>> ---
>>  arch/arm/mach-omap2/pm34xx.c |    6 ++++--
>>  1 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
>> index e80d59f..4cbeff1 100644
>> --- a/arch/arm/mach-omap2/pm34xx.c
>> +++ b/arch/arm/mach-omap2/pm34xx.c
>> @@ -264,8 +264,10 @@ static irqreturn_t prcm_interrupt_handler (int irq, void *dev_id)
>>  					       CM_FCLKEN);
>>  			cm_set_mod_reg_bits(wkst, OMAP3430ES2_USBHOST_MOD,
>>  					    CM_ICLKEN);
>> -			cm_set_mod_reg_bits(wkst, OMAP3430ES2_USBHOST_MOD,
>> -					    CM_FCLKEN);
>> +			cm_set_mod_reg_bits((1<<OMAP3430ES2_EN_USBHOST2_SHIFT)|
>> +					(1<<OMAP3430ES2_EN_USBHOST1_SHIFT),
>> +					OMAP3430ES2_USBHOST_MOD,
>> +					CM_FCLKEN);
>
>Instead how about keeping original code, but just add something like:
>
>        /* We don't know whether HOST1 or HOST2 woke us up, so
>         * enable both clocks. */
>        clken = wkst | (1 << OMAP3430ES2_EN_USBHOST2_SHIFT);

Ok looks cleaner. Will have this in v2 patch.

>
>Then write 'clken' to the FCLKEN reg and original 'wkst' to the WKST
>reg...
>
>>  			prm_write_mod_reg(wkst, OMAP3430ES2_USBHOST_MOD,
>>  					  PM_WKST);
>
>otherwise you're writing undefined bits here.

No. Original patch does not write any undefined bits. 
Wkst is 0x1 always.

>
>Kevin
>

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