can add feature for gpio-poweroff if kernal without device tree option

[junwushi]

the file ./drivers/power/reset/gpio-poweroff.c i check that is only support device tree kennel for define power off GPIO pin,but i am not use device tree to build kernel, i want define it in dev.c. can add this feature?

[junwushi]

other question,please help me check.i want read wake up source register value in user application. but always read value is zero. why?

#define SYS_BA 0xb0000000
#define REG_WKUPSSR 0x5c
unsigned int getwakupsource(void) {
unsigned int value;
int mem_fd = open("/dev/mem", O_RDWR | O_SYNC);
if (mem_fd == -1) {
printf("open /dev/mem fail\n");
return 0;
}
unsigned char virt_regaddr = (unsigned char) mmap(0, 0x1000,
PROT_READ | PROT_WRITE, MAP_SHARED, mem_fd, SYS_BA);
if (virt_regaddr == NULL) {
close(mem_fd);
printf("mmap mem fail\n");
return 0;
}
value = ((unsigned int) (virt_regaddr));
printf("PID:0x%x\n", value);
value = *((unsigned int *) (virt_regaddr + REG_WKUPSSR));
munmap(virt_regaddr, 0x1000);
close(mem_fd);
return value;
}

[yachen]

Hi,

Because the wake up source is cleared in arch/arm/mach-nuc970/pm.c after resume. Please csearch following line in pm.c
__raw_writel(__raw_readl(REG_WKUPSER), REG_WKUPSSR); // clear wake source flag

Sincerely,

Yi-An Chen

[junwushi]

i think that put it at fisrt line is better in the funcation of pm.c?

[yachen]

Yup, updated. Relocate the clear wakeup flag code.

[yachen]

Following code works fine here. Not sure what goes wrong at your environment.

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/mman.h>

#define DEV 	"/dev/mem"
#define BA	0xB0000000
int main(int argc, char **argv)
{
	int offset, fd;
	unsigned char *va;

	if(argc == 1) {
		printf("Usage: mem <offset>\n");
		return 0;
	}

	offset = atol(argv[1]);
	
	fd = open(DEV, O_RDWR | O_SYNC);
	if(fd < 0) {
		printf("Open /dev/mem failed\n");
		return 0;
	}

	va = mmap(0, 0x1000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, BA);
	if(va == NULL) {
		printf("mmap failed\n");
		return 0;
	}

	printf("=>%08x\n", *(unsigned int volatile *)(va + offset));

	munmap(va, 0x1000);
	close(fd);
}

[junwushi]

thanks

[yachen]

If you simply want to use GPIO to detect power off event, you can put it in NUC970 GPIO driver.

[junwushi]

no,i want after system shutdown to cut main power of device.so need override pm_power_0ff() funtion.it is lke below

/*

• Toggles a GPIO pin to power down a device
• Jamie Lentin jm@lentin.co.uk
• Andrew Lunn andrew@lunn.ch
• Copyright (C) 2012 Jamie Lentin
• This program is free software; you can redistribute it and/or modify
• it under the terms of the GNU General Public License version 2 as
• published by the Free Software Foundation.

*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>
#include <linux/module.h>

/*

• Hold configuration here, cannot be more than one instance of the driver
• since pm_power_off itself is global.
  */
  static int gpio_num = -1;
  //static int gpio_active_low;

static void gpio_poweroff_do_poweroff(void) {
//BUG_ON(!gpio_is_valid(gpio_num));

/* drive it active, also inactive->active edge */
//gpio_direction_output(gpio_num, !gpio_active_low);
//mdelay(100);
/* drive inactive, also active->inactive edge */
//gpio_set_value(gpio_num, gpio_active_low);
//mdelay(100);
/* drive it active, also inactive->active edge */
gpio_direction_output(gpio_num, 1);
//printk("power down now\n");
/* give it some time */

// mdelay(3000);
//WARN_ON(1);
}

static int gpio_poweroff_probe(struct platform_device pdev) {
// enum of_gpio_flags flags;
//bool input = false;
int ret;
//printk("%s:probe1\n",func);
/ If a pm_power_off function has already been added, leave it alone */
if (pm_power_off != NULL) {
pr_err("%s: pm_power_off function already registered", func);
return -EBUSY;
}
gpio_num = NUC970_PE4;
//gpio_num = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
if (!gpio_is_valid(gpio_num))
{
pr_err("%s: gpio num is not valid", func);
return gpio_num;
}
//gpio_active_low = flags & OF_GPIO_ACTIVE_LOW;

//input = of_property_read_bool(pdev->dev.of_node, "input");

ret = gpio_request(gpio_num, NULL);
if (ret) {
	pr_err("%s: Could not get GPIO %d", __func__, gpio_num);
	return ret;
}

if (gpio_direction_output(gpio_num, 0)) {
	pr_err("Could not set direction of GPIO %d", gpio_num);
	goto err;
}

pm_power_off = &gpio_poweroff_do_poweroff;
//printk("%s:probe2\n",__func__);
return 0;

err: gpio_free(gpio_num);
return -ENODEV;

}

static int gpio_poweroff_remove(struct platform_device *pdev) {
gpio_free(gpio_num);
if (pm_power_off == &gpio_poweroff_do_poweroff)
pm_power_off = NULL;

return 0;

}

#if defined(CONFIG_OF)
static const struct of_device_id of_gpio_poweroff_match[] = {
{ .compatible = "poweroff-gpio"},
{ },
};
MODULE_DEVICE_TABLE(of, of_gpio_poweroff_match);
#endif

static struct platform_driver gpio_poweroff_driver = {
.probe = gpio_poweroff_probe,
.remove = gpio_poweroff_remove,
.driver = {
.name = "poweroff-gpio",
.owner = THIS_MODULE,
#if defined(CONFIG_OF)
.of_match_table = of_match_ptr(of_gpio_poweroff_match),
#endif
},
};

module_platform_driver(gpio_poweroff_driver);

MODULE_DESCRIPTION("GPIO poweroff driver");
MODULE_LICENSE("GPL v2");