imx233 2.6.31 GPIO as wakeup source

[whitewool]

Dear all,

we are completing the hw design of a new mobile device based on imx233 and SW developed on L2.631 SDK,

This device is intended to massively use linux standby and suspend to ram to optimize power consumption.

We decided to use a GPIO driven by a micro controller to wake up the OS., but we can test this function only later, when HW has been developed

Please can you let me know if L2.6.31_10.05 BSP support the possibility to set GPIOs as wakeup sources (for example using echo enabled > /sys/class/gpio/gpio<n>/power/wakeup)

really Thanks for any hint

Alberto

[alejandrolozan1 · Accepted solution]

Hi,

Sorry for the delay.

It is possible to wake up from suspend by GPIO.Actually suspend mode is wait-for-interrupt.  Before enter suspend, you enable the interrupt.And then trigger the interrupt in suspend, system will wake up.You can check function avic_init_irq of arch/arm/plat-mxs/ icoll.c what irq is registered and whether gpio_to_irq() is registered.If not registered,  enable_irq_wake will fail.

Best Regards,

Alejandro

[whitewool]

Thanks so much, Alejandro

Best regards

Alberto

[whitewool]

Thanks again for you help Alejandro.

I just catch this occasion for another question.

As you said imx233 bsp currently support only standby (WFI).

Just in the last month our custimers are asking are asking more and more standby time for the device without battery discharge (battery is 2600mAh).

This is hard with WFI only. 20mA normal consumption of the device during "application standby" only reduce at 18mA with Linux standby.

Do you know if and where a suspend to ram implementation for imx233 can be found, can yoy give me a suggestion abaut that?

Thanks

Alberto

[gusarambula]

alejandrolozano, would you please comment on this?