mfd: mp2629: Add support for mps battery charger

mp2629 is a highly-integrated switching-mode battery charge management
device for single-cell Li-ion or Li-polymer battery.

Add MFD core enables chip access for ADC driver for battery readings,
and a power supply battery-charger driver

Signed-off-by: Saravanan Sekar <sravanhome@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -434,6 +434,15 @@ config MFD_MC13XXX_I2C
 	help
 	  Select this if your MC13xxx is connected via an I2C bus.
 
+config MFD_MP2629
+	tristate "Monolithic Power Systems MP2629 ADC and Battery charger"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Select this option to enable support for Monolithic Power Systems
+	  battery charger. This provides ADC, thermal and battery charger power
+	  management functions.
+
 config MFD_MXS_LRADC
 	tristate "Freescale i.MX23/i.MX28 LRADC"
 	depends on ARCH_MXS || COMPILE_TEST

drivers/mfd/Makefile

@@ -170,6 +170,8 @@ obj-$(CONFIG_MFD_MAX8925)	+= max8925.o
 obj-$(CONFIG_MFD_MAX8997)	+= max8997.o max8997-irq.o
 obj-$(CONFIG_MFD_MAX8998)	+= max8998.o max8998-irq.o
 
+obj-$(CONFIG_MFD_MP2629)	+= mp2629.o
+
 pcf50633-objs			:= pcf50633-core.o pcf50633-irq.o
 obj-$(CONFIG_MFD_PCF50633)	+= pcf50633.o
 obj-$(CONFIG_PCF50633_ADC)	+= pcf50633-adc.o

drivers/mfd/mp2629.c

@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * MP2629 parent driver for ADC and battery charger
+ *
+ * Copyright 2020 Monolithic Power Systems, Inc
+ *
+ * Author: Saravanan Sekar <sravanhome@gmail.com>
+ */
+
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/mp2629.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+static const struct mfd_cell mp2629_cell[] = {
+	{
+		.name = "mp2629_adc",
+		.of_compatible = "mps,mp2629_adc",
+	},
+	{
+		.name = "mp2629_charger",
+		.of_compatible = "mps,mp2629_charger",
+	}
+};
+
+static const struct regmap_config mp2629_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x17,
+};
+
+static int mp2629_probe(struct i2c_client *client)
+{
+	struct mp2629_data *ddata;
+	int ret;
+
+	ddata = devm_kzalloc(&client->dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	ddata->dev = &client->dev;
+	i2c_set_clientdata(client, ddata);
+
+	ddata->regmap = devm_regmap_init_i2c(client, &mp2629_regmap_config);
+	if (IS_ERR(ddata->regmap)) {
+		dev_err(ddata->dev, "Failed to allocate regmap\n");
+		return PTR_ERR(ddata->regmap);
+	}
+
+	ret = devm_mfd_add_devices(ddata->dev, PLATFORM_DEVID_AUTO, mp2629_cell,
+				   ARRAY_SIZE(mp2629_cell), NULL, 0, NULL);
+	if (ret)
+		dev_err(ddata->dev, "Failed to register sub-devices %d\n", ret);
+
+	return ret;
+}
+
+static const struct of_device_id mp2629_of_match[] = {
+	{ .compatible = "mps,mp2629"},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mp2629_of_match);
+
+static struct i2c_driver mp2629_driver = {
+	.driver = {
+		.name = "mp2629",
+		.of_match_table = mp2629_of_match,
+	},
+	.probe_new	= mp2629_probe,
+};
+module_i2c_driver(mp2629_driver);
+
+MODULE_AUTHOR("Saravanan Sekar <sravanhome@gmail.com>");
+MODULE_DESCRIPTION("MP2629 Battery charger parent driver");
+MODULE_LICENSE("GPL");

include/linux/mfd/mp2629.h

@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2020 Monolithic Power Systems, Inc
+ */
+
+#ifndef __MP2629_H__
+#define __MP2629_H__
+
+#include <linux/device.h>
+#include <linux/regmap.h>
+
+struct mp2629_data {
+	struct device *dev;
+	struct regmap *regmap;
+};
+
+#endif