power: reset: Add as3722 power-off driver

ams AS3722 supports the power off functionality to turn off system.

This commit adds power off driver for ams AS3722.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Anton Vorontsov <anton@enomsg.org>

drivers/power/reset/Kconfig

@@ -6,6 +6,12 @@ menuconfig POWER_RESET
 
 	  Say Y here to enable board reset and power off
 
+config POWER_RESET_AS3722
+	bool "ams AS3722 power-off driver"
+	depends on MFD_AS3722 && POWER_RESET
+	help
+	  This driver supports turning off board via a ams AS3722 power-off.
+
 config POWER_RESET_GPIO
 	bool "GPIO power-off driver"
 	depends on OF_GPIO && POWER_RESET

drivers/power/reset/Makefile

@@ -1,3 +1,4 @@
+obj-$(CONFIG_POWER_RESET_AS3722) += as3722-poweroff.o
 obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
 obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
 obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o

drivers/power/reset/as3722-poweroff.c

@@ -0,0 +1,96 @@
+/*
+ * Power off driver for ams AS3722 device.
+ *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Author: Laxman Dewangan <ldewangan@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/mfd/as3722.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+struct as3722_poweroff {
+	struct device *dev;
+	struct as3722 *as3722;
+};
+
+static struct as3722_poweroff *as3722_pm_poweroff;
+
+static void as3722_pm_power_off(void)
+{
+	int ret;
+
+	if (!as3722_pm_poweroff) {
+		pr_err("AS3722 poweroff is not initialised\n");
+		return;
+	}
+
+	ret = as3722_update_bits(as3722_pm_poweroff->as3722,
+		AS3722_RESET_CONTROL_REG, AS3722_POWER_OFF, AS3722_POWER_OFF);
+	if (ret < 0)
+		dev_err(as3722_pm_poweroff->dev,
+			"RESET_CONTROL_REG update failed, %d\n", ret);
+}
+
+static int as3722_poweroff_probe(struct platform_device *pdev)
+{
+	struct as3722_poweroff *as3722_poweroff;
+	struct device_node *np = pdev->dev.parent->of_node;
+
+	if (!np)
+		return -EINVAL;
+
+	if (!of_property_read_bool(np, "ams,system-power-controller"))
+		return 0;
+
+	as3722_poweroff = devm_kzalloc(&pdev->dev, sizeof(*as3722_poweroff),
+				GFP_KERNEL);
+	if (!as3722_poweroff)
+		return -ENOMEM;
+
+	as3722_poweroff->as3722 = dev_get_drvdata(pdev->dev.parent);
+	as3722_poweroff->dev = &pdev->dev;
+	as3722_pm_poweroff = as3722_poweroff;
+	if (!pm_power_off)
+		pm_power_off = as3722_pm_power_off;
+
+	return 0;
+}
+
+static int as3722_poweroff_remove(struct platform_device *pdev)
+{
+	if (pm_power_off == as3722_pm_power_off)
+		pm_power_off = NULL;
+	as3722_pm_poweroff = NULL;
+
+	return 0;
+}
+
+static struct platform_driver as3722_poweroff_driver = {
+	.driver = {
+		.name = "as3722-power-off",
+		.owner = THIS_MODULE,
+	},
+	.probe = as3722_poweroff_probe,
+	.remove = as3722_poweroff_remove,
+};
+
+module_platform_driver(as3722_poweroff_driver);
+
+MODULE_DESCRIPTION("Power off driver for ams AS3722 PMIC Device");
+MODULE_ALIAS("platform:as3722-power-off");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");