Linux "gpio-poweroff" won't load

[allard]

I'm trying to add the linux "gpio-poweroff" function to the distribution package. I've added the following to my device tree:

gpio-poweroff {
	compatible = "gpio-poweroff";
	gpios = <&gpioe 1 GPIO_ACTIVE_HIGH>;
	timeout-ms = <3000>;
};

The kernel/device tree compiles OK, but the poweroff function does not work. The logs give the following lines about the poweroff:

[    1.482136] poweroff-gpio gpio-poweroff: gpio_poweroff_probe: pm_power_off function already registered
[    1.482174] poweroff-gpio: probe of gpio-poweroff failed with error -16

So I guess openSTLinux already has some handler attached? How do I disable this?

[Christophe Guibout]

Hi @allard​ ,

gpio-poweroff is not loadable because STM32MP supports power domains.

pm_power_off is already registered in stm32_pm_domain_add function (drivers/soc/st/stm32_pm_domain.c) :

domain->genpd.power_off = stm32_pd_power_off;

This feature is under CONFIG_STM32_PM_DOMAINS switch, but I don't recommand to disable it as it's part of SoC.

BR,

Christophe

[Emma · Accepted solution]

Hi @allard​ ,

gpio-poweroff is registered to psci_sys_poweroff in firmware/psci.c which invokes a PSCI (Power State Coordination Interface

) function which is implemented in TF-A.

I added code to set my poweroff gpio in TF-A. Not sure if this is the correct way to do it. If you do this, also note that the system_off_mode is defined to STM32_PM_CSTOP_ALLOW_STANDBY_DDR_OFF in the CubeMX-generated device tree for TF-A; I changed it to STM32_PM_SHUTDOWN.

[allard]

@Emma​ @Christophe Guibout​ 

This should be enough info to get me going, thanks both.

[SMich.1]

hi, can you sow me some example of how to add gpio in tf-a to power off my board?

[Emma]

In file plat/st/stm32mp1/stm32mp1_low_power.c, function enter_shutdown(void) I put the following code after the DDR has been set in self-refresh:

/* Activate the poweroff GPIO (active low) */

uint32_t poweroff_gpio_clk = GPIOB;

uintptr_t poweroff_gpio_port = GPIOB_BASE;

uint32_t poweroff_gpio_pin = 10;

stm32mp_clk_enable(poweroff_gpio_clk);

/* Bit Reset Register (BRR): Set bit to set low output value */

mmio_setbits_32(poweroff_gpio_port + 0x28, 1 << poweroff_gpio_pin);

/* Output Type Register (OTYPER): Clear bit to configure push-pull */

mmio_clrbits_32(poweroff_gpio_port + 0x04, 1 << poweroff_gpio_pin);

/* Mode Register (MODER): 01 for GPIO output */

mmio_clrsetbits_32(poweroff_gpio_port, 1 << (poweroff_gpio_pin*2 +1),

                  1 << (poweroff_gpio_pin*2));

udelay(100);

/* If that didn't work, switch off the PMIC */

If your GPIO is active high, use BSRR (offset 0x18) instead of BRR.

Also set system_off_soc_mode to <STM32_PM_SHUTDOWN> in your device tree.

[SMich.1]

Tnx Emma, it power off the pmic immediately ? there is a way to make some delay of couple of seconds you think?

[SScar.2]

Hi there, 

I know that this reply was posted 3 years ago, but I'm facing the same problem right now. 

Your solution seems the best around the internet, but I have a question: I can't see the enter_shutdown() function in my distribution! In stm32mp1_low_power.c file, I Have enter_cstop() and enter_csleep() functions...    

I also can see these pretty interesting lines: 

void stm32_enter_low_power(uint32_t mode, uint32_t nsec_addr)
{
	switch (mode) {
	case STM32_PM_SHUTDOWN:
		break;

	case STM32_PM_CSLEEP_RUN:
		enter_csleep();
		break;

	default:
		enter_cstop(mode, nsec_addr);
		break;
	}
}

Did you create the function yourself?  If yes, how did you write that? 
I think that is a pretty big feature setting a gpio-poweroff for a Linux-embedded board, I don't know why ST doesn't give any documentation about that... 
Thanks a lot!