power: reset: Add generic SYSCON register mapped poweroff.

Add a generic SYSCON register mapped poweroff mechanism.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

3 files changed, 110 insertions, 0 deletions

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 6f791fbb1c96..aad9c3318c02 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -151,6 +151,13 @@ config POWER_RESET_SYSCON
         help
           Reboot support for generic SYSCON mapped register reset.
 
+config POWER_RESET_SYSCON_POWEROFF
+        bool "Generic SYSCON regmap poweroff driver"
+        depends on OF
+        select MFD_SYSCON
+        help
+          Poweroff support for generic SYSCON mapped register poweroff.
+
 config POWER_RESET_RMOBILE
         tristate "Renesas R-Mobile reset driver"
         depends on ARCH_RMOBILE || COMPILE_TEST
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index 11de15bae52e..dbe06c368743 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -17,4 +17,5 @@ obj-$(CONFIG_POWER_RESET_VEXPRESS) += vexpress-poweroff.o
 obj-$(CONFIG_POWER_RESET_XGENE) += xgene-reboot.o
 obj-$(CONFIG_POWER_RESET_KEYSTONE) += keystone-reset.o
 obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o
+obj-$(CONFIG_POWER_RESET_SYSCON_POWEROFF) += syscon-poweroff.o
 obj-$(CONFIG_POWER_RESET_RMOBILE) += rmobile-reset.o
diff --git a/drivers/power/reset/syscon-poweroff.c b/drivers/power/reset/syscon-poweroff.c
new file mode 100644
index 000000000000..5560b0dbc180
--- /dev/null
+++ b/drivers/power/reset/syscon-poweroff.c
@@ -0,0 +1,102 @@
+/*
+ * Generic Syscon Poweroff Driver
+ *
+ * Copyright (c) 2015, National Instruments Corp.
+ * Author: Moritz Fischer <moritz.fischer@ettus.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kallsyms.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/notifier.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/regmap.h>
+
+static struct regmap *map;
+static u32 offset;
+static u32 mask;
+
+void syscon_poweroff(void)
+{
+        /* Issue the poweroff */
+        regmap_write(map, offset, mask);
+
+        mdelay(1000);
+
+        pr_emerg("Unable to poweroff system\n");
+}
+
+static int syscon_poweroff_probe(struct platform_device *pdev)
+{
+        char symname[KSYM_NAME_LEN];
+
+        map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap");
+        if (IS_ERR(map)) {
+                dev_err(&pdev->dev, "unable to get syscon");
+                return PTR_ERR(map);
+        }
+
+        if (of_property_read_u32(pdev->dev.of_node, "offset", &offset)) {
+                dev_err(&pdev->dev, "unable to read 'offset'");
+                return -EINVAL;
+        }
+
+        if (of_property_read_u32(pdev->dev.of_node, "mask", &mask)) {
+                dev_err(&pdev->dev, "unable to read 'mask'");
+                return -EINVAL;
+        }
+
+        if (pm_power_off) {
+                lookup_symbol_name((ulong)pm_power_off, symname);
+                dev_err(&pdev->dev,
+                "pm_power_off already claimed %p %s",
+                pm_power_off, symname);
+                return -EBUSY;
+        }
+
+        pm_power_off = syscon_poweroff;
+
+        return 0;
+}
+
+static int syscon_poweroff_remove(struct platform_device *pdev)
+{
+        if (pm_power_off == syscon_poweroff)
+                pm_power_off = NULL;
+
+        return 0;
+}
+
+static const struct of_device_id syscon_poweroff_of_match[] = {
+        { .compatible = "syscon-poweroff" },
+        {}
+};
+
+static struct platform_driver syscon_poweroff_driver = {
+        .probe = syscon_poweroff_probe,
+        .remove = syscon_poweroff_remove,
+        .driver = {
+                .name = "syscon-poweroff",
+                .of_match_table = syscon_poweroff_of_match,
+        },
+};
+
+static int __init syscon_poweroff_register(void)
+{
+        return platform_driver_register(&syscon_poweroff_driver);
+}
+device_initcall(syscon_poweroff_register);