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>

4 files changed, 82 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/power_supply/restart-poweroff.txt b/Documentation/devicetree/bindings/power_supply/restart-poweroff.txt
new file mode 100644
index 000000000000..5776e684afda
--- /dev/null
+++ b/Documentation/devicetree/bindings/power_supply/restart-poweroff.txt
@@ -0,0 +1,8 @@
+* Restart Power Off
+
+Buffalo Linkstation LS-XHL and LS-CHLv2, and other devices power off
+by restarting and letting u-boot keep hold of the machine until the
+user presses a button.
+
+Required Properties:
+- compatible: Should be "restart-poweroff"
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 6453aac701c0..1ae65b822864 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -22,3 +22,11 @@ config POWER_RESET_QNAP
           commands to the microcontroller which controls the main power.
 
           Say Y if you have a QNAP NAS.
+
+config POWER_RESET_RESTART
+        bool "Restart power-off driver"
+        depends on ARM
+        help
+          Some boards don't actually have the ability to power off.
+          Instead they restart, and u-boot holds the SoC until the
+          user presses a key. u-boot then boots into Linux.
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index c4d3b2d11b9e..0f317f50c56f 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
 obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
+obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
\ No newline at end of file
diff --git a/drivers/power/reset/restart-poweroff.c b/drivers/power/reset/restart-poweroff.c
new file mode 100644
index 000000000000..b11b9e887174
--- /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");