Merge tag 'dt' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

[can-eth-gw-linux.git] / drivers / power / reset / gpio-poweroff.c

diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c
new file mode 100644 (file)
index 0000000..0491e53
--- /dev/null
+++ b/drivers/power/reset/gpio-poweroff.c
@@ -0,0 +1,129 @@
+/*
+ * 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_num == -1);
+
+       /* drive it active */
+       gpio_direction_output(gpio_num, !gpio_active_low);
+       mdelay(100);
+       /* rising edge or drive inactive */
+       gpio_set_value(gpio_num, gpio_active_low);
+       mdelay(100);
+       /* falling edge */
+       gpio_set_value(gpio_num, !gpio_active_low);
+
+       /* give it some time */
+       mdelay(3000);
+
+       WARN_ON(1);
+}
+
+static int __devinit gpio_poweroff_probe(struct platform_device *pdev)
+{
+       enum of_gpio_flags flags;
+       bool input = false;
+       int ret;
+
+       /* 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 = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
+       if (gpio_num < 0) {
+               pr_err("%s: Could not get GPIO configuration: %d",
+                      __func__, gpio_num);
+               return -ENODEV;
+       }
+       gpio_active_low = flags & OF_GPIO_ACTIVE_LOW;
+
+       if (of_get_property(pdev->dev.of_node, "input", NULL))
+               input = true;
+
+       ret = gpio_request(gpio_num, "poweroff-gpio");
+       if (ret) {
+               pr_err("%s: Could not get GPIO %d", __func__, gpio_num);
+               return ret;
+       }
+       if (input) {
+               if (gpio_direction_input(gpio_num)) {
+                       pr_err("Could not set direction of GPIO %d to input",
+                              gpio_num);
+                       goto err;
+               }
+       } else {
+               if (gpio_direction_output(gpio_num, gpio_active_low)) {
+                       pr_err("Could not set direction of GPIO %d", gpio_num);
+                       goto err;
+               }
+       }
+
+       pm_power_off = &gpio_poweroff_do_poweroff;
+       return 0;
+
+err:
+       gpio_free(gpio_num);
+       return -ENODEV;
+}
+
+static int __devexit gpio_poweroff_remove(struct platform_device *pdev)
+{
+       if (gpio_num != -1)
+               gpio_free(gpio_num);
+       if (pm_power_off == &gpio_poweroff_do_poweroff)
+               pm_power_off = NULL;
+
+       return 0;
+}
+
+static const struct of_device_id of_gpio_poweroff_match[] = {
+       { .compatible = "gpio-poweroff", },
+       {},
+};
+
+static struct platform_driver gpio_poweroff_driver = {
+       .probe = gpio_poweroff_probe,
+       .remove = __devexit_p(gpio_poweroff_remove),
+       .driver = {
+                  .name = "poweroff-gpio",
+                  .owner = THIS_MODULE,
+                  .of_match_table = of_gpio_poweroff_match,
+                  },
+};
+
+module_platform_driver(gpio_poweroff_driver);
+
+MODULE_AUTHOR("Jamie Lentin <jm@lentin.co.uk>");
+MODULE_DESCRIPTION("GPIO poweroff driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:poweroff-gpio");