1 files changed, 111 insertions, 0 deletions
diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c
new file mode 100644
index 000000000..e5332f1db
--- /dev/null
+++ b/drivers/power/reset/gpio-poweroff.c
@@ -0,0 +1,111 @@
+/*
+ * 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/consumer.h>
+#include <linux/of_platform.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 struct gpio_desc *reset_gpio;
+
+static void gpio_poweroff_do_poweroff(void)
+{
+	BUG_ON(!reset_gpio);
+
+	/* drive it active, also inactive->active edge */
+	gpiod_direction_output(reset_gpio, 1);
+	mdelay(100);
+	/* drive inactive, also active->inactive edge */
+	gpiod_set_value(reset_gpio, 0);
+	mdelay(100);
+
+	/* drive it active, also inactive->active edge */
+	gpiod_set_value(reset_gpio, 1);
+
+	/* give it some time */
+	mdelay(3000);
+
+	WARN_ON(1);
+}
+
+static int gpio_poweroff_probe(struct platform_device *pdev)
+{
+	bool input = false;
+
+	/* If a pm_power_off function has already been added, leave it alone */
+	if (pm_power_off != NULL) {
+		dev_err(&pdev->dev,
+			"%s: pm_power_off function already registered",
+		       __func__);
+		return -EBUSY;
+	}
+
+	reset_gpio = devm_gpiod_get(&pdev->dev, NULL);
+	if (IS_ERR(reset_gpio))
+		return PTR_ERR(reset_gpio);
+
+	input = of_property_read_bool(pdev->dev.of_node, "input");
+
+	if (input) {
+		if (gpiod_direction_input(reset_gpio)) {
+			dev_err(&pdev->dev,
+				"Could not set direction of reset GPIO to input\n");
+			return -ENODEV;
+		}
+	} else {
+		if (gpiod_direction_output(reset_gpio, 0)) {
+			dev_err(&pdev->dev,
+				"Could not set direction of reset GPIO\n");
+			return -ENODEV;
+		}
+	}
+
+	pm_power_off = &gpio_poweroff_do_poweroff;
+	return 0;
+}
+
+static int gpio_poweroff_remove(struct platform_device *pdev)
+{
+	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 = gpio_poweroff_remove,
+	.driver = {
+		.name = "poweroff-gpio",
+		.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 v2");
+MODULE_ALIAS("platform:poweroff-gpio");