Felipe Balbi <balbi@xxxxxx> writes:
> Hi,
>
> On Tue, Oct 23, 2012 at 11:09:31AM -0700, Kevin Hilman wrote:
>> From: Kevin Hilman <khilman@xxxxxx>
>>
>> When debounce clocks are disabled, ensure that the banks
>> dbck_enable_mask is cleared also. Otherwise, context restore on
>> subsequent off-mode transition will restore previous value from the
>> shadow copies (bank->context.debounce*) leading to mismatch state
>> between driver state and hardware state.
>>
>> This was discovered when board code was doing
>>
>> gpio_request_one()
>> gpio_set_debounce()
>> gpio_free()
>>
>> which was leaving the GPIO debounce settings in a confused state.
>> Then, enabling off mode causing bogus state to be restored, leaving
>> GPIO debounce enabled which then prevented the CORE powerdomain from
>> transitioning.
>>
>> Reported-by: Paul Walmsley <paul@xxxxxxxxx>
>> Cc: Igor Grinberg <grinberg@xxxxxxxxxxxxxx>
>> Signed-off-by: Kevin Hilman <khilman@xxxxxx>
>
> looks like this deserves a Cc: stable@xxxxxxxxxxxxxxx tag.
>
Agreed. I think this goes all the way back to v3.5, but would've only
been seen on boards using a request/gpio_set_debounce/free sequence
combined with off-mode.
Linus, feel free to add the Cc: stable when commiting. Thanks.
>> ---
>> Applies on v3.7-rc2, targetted for v3.7.
>>
>> drivers/gpio/gpio-omap.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
>> index 94cbc84..dee2856 100644
>> --- a/drivers/gpio/gpio-omap.c
>> +++ b/drivers/gpio/gpio-omap.c
>> @@ -187,6 +187,7 @@ static inline void _gpio_dbck_disable(struct gpio_bank *bank)
>> * to detect events and generate interrupts at least on OMAP3.
>> */
>> __raw_writel(0, bank->base + bank->regs->debounce_en);
>> + bank->dbck_enable_mask = 0;
>
> shouldn't omap_gpio_restore_context() check for dbck_enabled instead of
> the mask ? I mean:
>
> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
> index 94cbc84..b3a39a7 100644
> --- a/drivers/gpio/gpio-omap.c
> +++ b/drivers/gpio/gpio-omap.c
> @@ -1371,7 +1371,7 @@ static void omap_gpio_restore_context(struct gpio_bank *bank)
> bank->base + bank->regs->dataout);
> __raw_writel(bank->context.oe, bank->base + bank->regs->direction);
>
> - if (bank->dbck_enable_mask) {
> + if (bank->dbck_enabled) {
> __raw_writel(bank->context.debounce, bank->base +
> bank->regs->debounce);
> __raw_writel(bank->context.debounce_en,
>
> the outcome would be the same, so it doesn't really matter. Just that,
> at least to me, it would look better.
I tried your version, and unfortunately, the outcome is not the same,
but don't plan to look into why. $SUBJECT version is targetted and
tested. If you want to cleanup the cosmetics here, please do in a
subsequent patch. This driver could certainly benefit from more
readability cleanups.
> No strong feelings though.
Good. I'll take that as an Ack. :)
Kevin
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