[PATCH v4 04/12] gpio/omap: remove saved_wakeup field from struct gpio_bank

[tarun.kanti@ti.com (DebBarma, Tarun Kanti)]

Hi Roger,

On Mon, Jul 9, 2012 at 3:13 PM, Roger Quadros <rogerq@ti.com> wrote:
> Hi,
>
> Just bumped across this patch and have a query.
>
> On 03/16/2012 04:05 PM, Tarun Kanti DebBarma wrote:
>> There is no more need to have saved_wakeup because bank->context.wake_en
>> already holds that value. So getting rid of read/write operation associated
>> with this field.
>>
>> Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@ti.com>
>> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
>> Acked-by: Felipe Balbi <balbi@ti.com>
>> ---
>>  drivers/gpio/gpio-omap.c |   12 +++---------
>>  1 files changed, 3 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
>> index 3a4f151..3b91ade 100644
>> --- a/drivers/gpio/gpio-omap.c
>> +++ b/drivers/gpio/gpio-omap.c
>> @@ -57,7 +57,6 @@ struct gpio_bank {
>>       u16 irq;
>>       int irq_base;
>>       struct irq_domain *domain;
>> -     u32 saved_wakeup;
>>       u32 non_wakeup_gpios;
>>       u32 enabled_non_wakeup_gpios;
>>       struct gpio_regs context;
>> @@ -777,7 +776,6 @@ static int omap_mpuio_suspend_noirq(struct device *dev)
>>       unsigned long           flags;
>>
>>       spin_lock_irqsave(&bank->lock, flags);
>> -     bank->saved_wakeup = __raw_readl(mask_reg);
>>       __raw_writel(0xffff & ~bank->context.wake_en, mask_reg);
>
> OK, here you are overwriting the mask_reg with the wakeup bitmask
> without saving the mask_reg's original content.
This is based upon understanding that set_gpio_trigger() is the common
function where update of wake_en register takes place. Unless, mask_reg
in this case refers to something else, effectively we would be saving the
same value to saved_wakeup what is already present in wake_en.
I will verify this specific to this function.

>
>>       spin_unlock_irqrestore(&bank->lock, flags);
>>
>> @@ -793,7 +791,7 @@ static int omap_mpuio_resume_noirq(struct device *dev)
>>       unsigned long           flags;
>>
>>       spin_lock_irqsave(&bank->lock, flags);
>> -     __raw_writel(bank->saved_wakeup, mask_reg);
>> +     __raw_writel(bank->context.wake_en, mask_reg);
>
> Now you are restoring nothing but the same content that you stored
> during suspend. This will cause the non-wakeup gpio interrupts to get
> masked between a suspend/resume. So isn't this a bug?
That's right, the same value is restored back which was last updated in
set_gpio_trigger() that got stored in wake_en register. Let me know if
I am missing your points here.

>
> Proper solution would be to save the mask_reg context into another
> register than context.wake_en during suspend.
As I said, this would make sense if mask_reg is referring to different
register than what is used in set_gpio_trigger(). I will have a look.

BTW, did you observe anything unusual during some testing?

Thanks.
--
Tarun
>
>>       spin_unlock_irqrestore(&bank->lock, flags);
>>
>>       return 0;
>
>
> cheers,
> -roger