power/reset: Add a new driver implementing 'power off by restarting'

Some devices, Buffalo Linkstation LS-XHL and LS-CHLv2 for example,
power-off by restarting to letting u-boot hold the SoC until the user
presses a key. Add a generic driver to implement this. It binds a function
to pm_power_off, which calls arm_pm_restart.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Anton Vorontsov <anton@enomsg.org>

1 files changed, 65 insertions, 0 deletions

diff --git a/drivers/power/reset/restart-poweroff.c b/drivers/power/reset/restart-poweroff.c
new file mode 100644
index 00000000000..b11b9e88717
--- /dev/null
+++ b/drivers/power/reset/restart-poweroff.c
@@ -0,0 +1,65 @@
+/*
+ * Power off by restarting and let u-boot keep hold of the machine
+ * until the user presses a button for example.
+ *
+ * Andrew Lunn <andrew@lunn.ch>
+ *
+ * Copyright (C) 2012 Andrew Lunn
+ *
+ * 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/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/module.h>
+#include <asm/system_misc.h>
+
+static void restart_poweroff_do_poweroff(void)
+{
+	arm_pm_restart('h', NULL);
+}
+
+static int __devinit restart_poweroff_probe(struct platform_device *pdev)
+{
+	/* If a pm_power_off function has already been added, leave it alone */
+	if (pm_power_off != NULL) {
+		dev_err(&pdev->dev,
+			"pm_power_off function already registered");
+		return -EBUSY;
+	}
+
+	pm_power_off = &restart_poweroff_do_poweroff;
+	return 0;
+}
+
+static int __devexit restart_poweroff_remove(struct platform_device *pdev)
+{
+	if (pm_power_off == &restart_poweroff_do_poweroff)
+		pm_power_off = NULL;
+
+	return 0;
+}
+
+static const struct of_device_id of_restart_poweroff_match[] = {
+	{ .compatible = "restart-poweroff", },
+	{},
+};
+
+static struct platform_driver restart_poweroff_driver = {
+	.probe = restart_poweroff_probe,
+	.remove = __devexit_p(restart_poweroff_remove),
+	.driver = {
+		.name = "poweroff-restart",
+		.owner = THIS_MODULE,
+		.of_match_table = of_restart_poweroff_match,
+	},
+};
+module_platform_driver(restart_poweroff_driver);
+
+MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
+MODULE_DESCRIPTION("restart poweroff driver");
+MODULE_LICENSE("GPLv2");
+MODULE_ALIAS("platform:poweroff-restart");