If mx6sx is a spi slave, is it possible to use SS pin as wake up source when it's suspend to ram state?

[alex_park]

Hello, I'm currently using imx6sx as a slave spi. (kernel 3.10.53 + patch spi slave (see attachment) )

while imx6sx is in suspend to ram state, I want to wake it up by QSPI1B_SSO_B from some external spi master device.

Is anybody who knows how to do it ?

[igorpadykov]

Hi MINKYU

ecspi module has not wake capabilities as for example uart, so

one can configure ss pin as gpio for wake, after resuming return it as ss function.

One can look at example "wakeup-gpios" in imx6sx-sabreauto.dts

linux-2.6-imx.git - Freescale i.MX Linux Tree 

Best regards
igor
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[alex_park]

Hello igorpadykov‌

is pin below available for wakeup source?

My engineer tried to do with that pin and it seems it doesn't work.

Please help me.

<MX6SX_PAD_QSPI1B_SS0_B__GPIO4_IO_30>

.

.

.

&ecspi3 {
fsl,spi-num-chipselects = <1>;
cs-gpios = <&gpio4 30 0>;
pinctrl-names = "default";
wakeup-gpios = <&gpio4 30 0>;

.

.

.

[igorpadykov]

Hi MINKYU

I do not think that spi driver supports SS pin as wake up.

Please try to use it as separate (not as part of spi) gpio wake source.

Best regards
igor

[alex_park]

Hello igorpadykov‌ Thanx for quick response.

My attempt was to switch the ss pin to gpio when imx6 is in suspend to ram (echo mem> / sys / power / state), and switch to ss pin when resume.
Is not it the same context to use as a separate gpio you said?

[igorpadykov]

Hi MINKYU

I think you are right, but these codes are not implemented in existing driver,

you can try to debug it. In general, nxp has special service for helping with porting drivers

NXP Professional Services|NXP 

Best regards
igor