Re: [PATCH 2/6] OMAP3: GPIO: Only enable WAKEUPEN for edge detection GPIOs

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Tony Lindgren <tony@xxxxxxxxxxx> writes:

> * Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> [100503 16:28]:
>> From: Chunqiu Wang <cqwang@xxxxxxxxxxxx>
>> 
>> According to the GPIO 'Wakeup and Interrupt' section of the TRM[1],
>> wake-up requests can only be generated on edge transitions.
>> 
>> Also for OMAP3, only edge GPIOs may lose interrupts when PER enters
>> RET/OFF state, this is addressed by gpio prepare|resume idle functions
>
> There's a generic solution to this problem. The solution is to temporarily
> set the level GPIO pins into edge for the duration of idle. Then
> they need to be set back to level after the system is woken up.

Sure, but that doesn't change the need for this patch which is
a correctness fix.

Adding wakeup support for level GPIOs would be a separate fix.

Kevin


>
>  
>> [1] Section 25.5.3.1 OMAP34xx_ES3.1_TRM_V_Q
>> 
>> Signed-off-by: Chunqiu Wang <cqwang@xxxxxxxxxxxx>
>> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
>> ---
>>  arch/arm/plat-omap/gpio.c |   14 ++++++++++++--
>>  1 files changed, 12 insertions(+), 2 deletions(-)
>> 
>> diff --git a/arch/arm/plat-omap/gpio.c b/arch/arm/plat-omap/gpio.c
>> index 678fd08..4d43cda 100644
>> --- a/arch/arm/plat-omap/gpio.c
>> +++ b/arch/arm/plat-omap/gpio.c
>> @@ -724,7 +724,11 @@ static inline void set_24xx_gpio_triggering(struct gpio_bank *bank, int gpio,
>>  							 OMAP4_GPIO_IRQWAKEN0);
>>  			}
>>  		} else {
>> -			if (trigger != 0)
>> +			/*
>> +			 * GPIO wakeup request can only be generated on edge
>> +			 * transitions
>> +			 */
>> +			if (trigger & IRQ_TYPE_EDGE_BOTH)
>>  				__raw_writel(1 << gpio, bank->base
>>  					+ OMAP24XX_GPIO_SETWKUENA);
>>  			else
>> @@ -734,7 +738,13 @@ static inline void set_24xx_gpio_triggering(struct gpio_bank *bank, int gpio,
>>  	}
>>  	/* This part needs to be executed always for OMAP34xx */
>>  	if (cpu_is_omap34xx() || (bank->non_wakeup_gpios & gpio_bit)) {
>> -		if (trigger != 0)
>> +		/*
>> +		 * Log the edge gpio and manually trigger the IRQ
>> +		 * after resume if the input level changes
>> +		 * to avoid irq lost during PER RET/OFF mode
>> +		 * Applies for omap2 non-wakeup gpio and all omap3 gpios
>> +		 */
>> +		if (trigger & IRQ_TYPE_EDGE_BOTH)
>>  			bank->enabled_non_wakeup_gpios |= gpio_bit;
>>  		else
>>  			bank->enabled_non_wakeup_gpios &= ~gpio_bit;
>> -- 
>> 1.7.0.2
>> 
>> --
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