regulator: Versatile Express regulator driver

Versatile Express voltage regulators

------------------------------------

Requires node properties:

- "compatible" value: "arm,vexpress-volt"

- "arm,vexpress-sysreg,func" when controlled via vexpress-sysreg

  (see Documentation/devicetree/bindings/arm/vexpress-sysreg.txt

  for more details)

Required regulator properties:

- "regulator-name"

- "regulator-always-on"

Optional regulator properties:

- "regulator-min-microvolt"

- "regulator-max-microvolt"

See Documentation/devicetree/bindings/regulator/regulator.txt

for more details about the regulator properties.

When no "regulator-[min|max]-microvolt" properties are defined,

the device is treated as fixed (or rather "read-only") regulator.

Example:

	volt@0 {

		compatible = "arm,vexpress-volt";

		arm,vexpress-sysreg,func = <2 0>;

		regulator-name = "Cores";

		regulator-min-microvolt = <800000>;

		regulator-max-microvolt = <1050000>;

		regulator-always-on;

	};

	  This driver supports the voltage regulators provided by

	  this family of companion chips.

config REGULATOR_VEXPRESS

	tristate "Versatile Express regulators"

	depends on VEXPRESS_CONFIG

	help

	  This driver provides support for voltage regulators available

	  on the ARM Ltd's Versatile Express platform.

config REGULATOR_WM831X

	tristate "Wolfson Microelectronics WM831x PMIC regulators"

	depends on MFD_WM831X

obj-$(CONFIG_REGULATOR_TPS65910) += tps65910-regulator.o

obj-$(CONFIG_REGULATOR_TPS65912) += tps65912-regulator.o

obj-$(CONFIG_REGULATOR_TWL4030) += twl-regulator.o

obj-$(CONFIG_REGULATOR_VEXPRESS) += vexpress.o

obj-$(CONFIG_REGULATOR_WM831X) += wm831x-dcdc.o

obj-$(CONFIG_REGULATOR_WM831X) += wm831x-isink.o

obj-$(CONFIG_REGULATOR_WM831X) += wm831x-ldo.o

/*

 * 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.

 *

 * 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.

 *

 * Copyright (C) 2012 ARM Limited

 */

#define DRVNAME "vexpress-regulator"

#define pr_fmt(fmt) DRVNAME ": " fmt

#include <linux/device.h>

#include <linux/err.h>

#include <linux/module.h>

#include <linux/of_device.h>

#include <linux/regulator/driver.h>

#include <linux/regulator/machine.h>

#include <linux/regulator/of_regulator.h>

#include <linux/vexpress.h>

struct vexpress_regulator {

	struct regulator_desc desc;

	struct regulator_dev *regdev;

	struct vexpress_config_func *func;

};

static int vexpress_regulator_get_voltage(struct regulator_dev *regdev)

{

	struct vexpress_regulator *reg = rdev_get_drvdata(regdev);

	u32 uV;

	int err = vexpress_config_read(reg->func, 0, &uV);

	return err ? err : uV;

}

static int vexpress_regulator_set_voltage(struct regulator_dev *regdev,

		int min_uV, int max_uV, unsigned *selector)

{

	struct vexpress_regulator *reg = rdev_get_drvdata(regdev);

	return vexpress_config_write(reg->func, 0, min_uV);

}

static struct regulator_ops vexpress_regulator_ops_ro = {

	.get_voltage = vexpress_regulator_get_voltage,

};

static struct regulator_ops vexpress_regulator_ops = {

	.get_voltage = vexpress_regulator_get_voltage,

	.set_voltage = vexpress_regulator_set_voltage,

};

static int vexpress_regulator_probe(struct platform_device *pdev)

{

	int err;

	struct vexpress_regulator *reg;

	struct regulator_init_data *init_data;

	struct regulator_config config = { };

	reg = devm_kzalloc(&pdev->dev, sizeof(*reg), GFP_KERNEL);

	if (!reg) {

		err = -ENOMEM;

		goto error_kzalloc;

	}

	reg->func = vexpress_config_func_get_by_dev(&pdev->dev);

	if (!reg->func) {

		err = -ENXIO;

		goto error_get_func;

	}

	reg->desc.name = dev_name(&pdev->dev);

	reg->desc.type = REGULATOR_VOLTAGE;

	reg->desc.owner = THIS_MODULE;

	reg->desc.continuous_voltage_range = true;

	init_data = of_get_regulator_init_data(&pdev->dev, pdev->dev.of_node);

	if (!init_data) {

		err = -EINVAL;

		goto error_get_regulator_init_data;

	}

	init_data->constraints.apply_uV = 0;

	if (init_data->constraints.min_uV && init_data->constraints.max_uV)

		reg->desc.ops = &vexpress_regulator_ops;

	else

		reg->desc.ops = &vexpress_regulator_ops_ro;

	config.dev = &pdev->dev;

	config.init_data = init_data;

	config.driver_data = reg;

	config.of_node = pdev->dev.of_node;

	reg->regdev = regulator_register(&reg->desc, &config);

	if (IS_ERR(reg->regdev)) {

		err = PTR_ERR(reg->regdev);

		goto error_regulator_register;

	}

	platform_set_drvdata(pdev, reg);

	return 0;

error_regulator_register:

error_get_regulator_init_data:

	vexpress_config_func_put(reg->func);

error_get_func:

error_kzalloc:

	return err;

}

static int __devexit vexpress_regulator_remove(struct platform_device *pdev)

{

	struct vexpress_regulator *reg = platform_get_drvdata(pdev);

	vexpress_config_func_put(reg->func);

	regulator_unregister(reg->regdev);

	return 0;

}

static struct of_device_id vexpress_regulator_of_match[] = {

	{ .compatible = "arm,vexpress-volt", },

};

static struct platform_driver vexpress_regulator_driver = {

	.probe = vexpress_regulator_probe,

	.remove = __devexit_p(vexpress_regulator_remove),

	.driver	= {

		.name = DRVNAME,

		.owner = THIS_MODULE,

		.of_match_table = vexpress_regulator_of_match,

	},

};

module_platform_driver(vexpress_regulator_driver);

MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");

MODULE_DESCRIPTION("Versatile Express regulator");

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:vexpress-regulator");