mfd: act8945a: Add Active-semi ACT8945A PMIC MFD driver

This patch adds support for the Active-semi ACT8945A PMIC.
It is a Multi Function Device with the following subdevices:
 - Regulator
 - Charger

It is interfaced to the host controller using I2C interface,
ACT8945A is a child device of the I2C.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -18,6 +18,17 @@ config MFD_CS5535
 	  This is the core driver for CS5535/CS5536 MFD functions.  This is
           necessary for using the board's GPIO and MFGPT functionality.
 
+config MFD_ACT8945A
+	tristate "Active-semi ACT8945A"
+	select MFD_CORE
+	select REGMAP_I2C
+	depends on I2C && OF
+	help
+	  Support for the ACT8945A PMIC from Active-semi. This device
+	  features three step-down DC/DC converters and four low-dropout
+	  linear regulators, along with a complete ActivePath battery
+	  charger.
+
 config MFD_AS3711
 	bool "AMS AS3711"
 	select MFD_CORE

drivers/mfd/Makefile

@@ -6,6 +6,7 @@
 obj-$(CONFIG_MFD_88PM860X)	+= 88pm860x.o
 obj-$(CONFIG_MFD_88PM800)	+= 88pm800.o 88pm80x.o
 obj-$(CONFIG_MFD_88PM805)	+= 88pm805.o 88pm80x.o
+obj-$(CONFIG_MFD_ACT8945A)	+= act8945a.o
 obj-$(CONFIG_MFD_SM501)		+= sm501.o
 obj-$(CONFIG_MFD_ASIC3)		+= asic3.o tmio_core.o
 obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o

drivers/mfd/act8945a.c

@@ -0,0 +1,102 @@
+/*
+ * MFD driver for Active-semi ACT8945a PMIC
+ *
+ * Copyright (C) 2015 Atmel Corporation.
+ *
+ * Author: Wenyou Yang <wenyou.yang@atmel.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.
+ */
+
+#include <linux/i2c.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+static const struct mfd_cell act8945a_devs[] = {
+	{
+		.name = "act8945a-regulator",
+	},
+	{
+		.name = "act8945a-charger",
+	},
+};
+
+static const struct regmap_config act8945a_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int act8945a_i2c_probe(struct i2c_client *i2c,
+			      const struct i2c_device_id *id)
+{
+	int ret;
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_i2c(i2c, &act8945a_regmap_config);
+	if (IS_ERR(regmap)) {
+		ret = PTR_ERR(regmap);
+		dev_err(&i2c->dev, "regmap init failed: %d\n", ret);
+		return ret;
+	}
+
+	i2c_set_clientdata(i2c, regmap);
+
+	ret = mfd_add_devices(&i2c->dev, PLATFORM_DEVID_NONE, act8945a_devs,
+			      ARRAY_SIZE(act8945a_devs), NULL, 0, NULL);
+	if (ret) {
+		dev_err(&i2c->dev, "Failed to add sub devices\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int act8945a_i2c_remove(struct i2c_client *i2c)
+{
+	mfd_remove_devices(&i2c->dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id act8945a_i2c_id[] = {
+	{ "act8945a", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, act8945a_i2c_id);
+
+static const struct of_device_id act8945a_of_match[] = {
+	{ .compatible = "active-semi,act8945a", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, act8945a_of_match);
+
+static struct i2c_driver act8945a_i2c_driver = {
+	.driver = {
+		   .name = "act8945a",
+		   .of_match_table = of_match_ptr(act8945a_of_match),
+	},
+	.probe = act8945a_i2c_probe,
+	.remove = act8945a_i2c_remove,
+	.id_table = act8945a_i2c_id,
+};
+
+static int __init act8945a_i2c_init(void)
+{
+	return i2c_add_driver(&act8945a_i2c_driver);
+}
+subsys_initcall(act8945a_i2c_init);
+
+static void __exit act8945a_i2c_exit(void)
+{
+	i2c_del_driver(&act8945a_i2c_driver);
+}
+module_exit(act8945a_i2c_exit);
+
+MODULE_DESCRIPTION("ACT8945A PMIC multi-function driver");
+MODULE_AUTHOR("Wenyou Yang <wenyou.yang@atmel.com>");
+MODULE_LICENSE("GPL");