1/*
  2 * This program is free software; you can redistribute it and/or modify
  3 * it under the terms of the GNU General Public License version 2 as
  4 * published by the Free Software Foundation.
  5 *
  6 * This program is distributed in the hope that it will be useful,
  7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  9 * GNU General Public License for more details.
 10 *
 11 * Copyright (C) 2012 ARM Limited
 12 */
 13
 14#define DRVNAME "vexpress-regulator"
 15#define pr_fmt(fmt) DRVNAME ": " fmt
 16
 17#include <linux/device.h>
 18#include <linux/err.h>
 19#include <linux/module.h>
 20#include <linux/of_device.h>
 21#include <linux/regulator/driver.h>
 22#include <linux/regulator/machine.h>
 23#include <linux/regulator/of_regulator.h>
 24#include <linux/vexpress.h>
 25
 26struct vexpress_regulator {
 27	struct regulator_desc desc;
 28	struct regulator_dev *regdev;
 29	struct vexpress_config_func *func;
 30};
 31
 32static int vexpress_regulator_get_voltage(struct regulator_dev *regdev)
 33{
 34	struct vexpress_regulator *reg = rdev_get_drvdata(regdev);
 35	u32 uV;
 36	int err = vexpress_config_read(reg->func, 0, &uV);
 37
 38	return err ? err : uV;
 39}
 40
 41static int vexpress_regulator_set_voltage(struct regulator_dev *regdev,
 42		int min_uV, int max_uV, unsigned *selector)
 43{
 44	struct vexpress_regulator *reg = rdev_get_drvdata(regdev);
 45
 46	return vexpress_config_write(reg->func, 0, min_uV);
 47}
 48
 49static struct regulator_ops vexpress_regulator_ops_ro = {
 50	.get_voltage = vexpress_regulator_get_voltage,
 51};
 52
 53static struct regulator_ops vexpress_regulator_ops = {
 54	.get_voltage = vexpress_regulator_get_voltage,
 55	.set_voltage = vexpress_regulator_set_voltage,
 56};
 57
 58static int vexpress_regulator_probe(struct platform_device *pdev)
 59{
 60	int err;
 61	struct vexpress_regulator *reg;
 62	struct regulator_init_data *init_data;
 63	struct regulator_config config = { };
 64
 65	reg = devm_kzalloc(&pdev->dev, sizeof(*reg), GFP_KERNEL);
 66	if (!reg) {
 67		err = -ENOMEM;
 68		goto error_kzalloc;
 69	}
 70
 71	reg->func = vexpress_config_func_get_by_dev(&pdev->dev);
 72	if (!reg->func) {
 73		err = -ENXIO;
 74		goto error_get_func;
 75	}
 76
 77	reg->desc.name = dev_name(&pdev->dev);
 78	reg->desc.type = REGULATOR_VOLTAGE;
 79	reg->desc.owner = THIS_MODULE;
 80	reg->desc.continuous_voltage_range = true;
 81
 82	init_data = of_get_regulator_init_data(&pdev->dev, pdev->dev.of_node);
 83	if (!init_data) {
 84		err = -EINVAL;
 85		goto error_get_regulator_init_data;
 86	}
 87
 88	init_data->constraints.apply_uV = 0;
 89	if (init_data->constraints.min_uV && init_data->constraints.max_uV)
 90		reg->desc.ops = &vexpress_regulator_ops;
 91	else
 92		reg->desc.ops = &vexpress_regulator_ops_ro;
 93
 94	config.dev = &pdev->dev;
 95	config.init_data = init_data;
 96	config.driver_data = reg;
 97	config.of_node = pdev->dev.of_node;
 98
 99	reg->regdev = devm_regulator_register(&pdev->dev, &reg->desc, &config);
100	if (IS_ERR(reg->regdev)) {
101		err = PTR_ERR(reg->regdev);
102		goto error_regulator_register;
103	}
104
105	platform_set_drvdata(pdev, reg);
106
107	return 0;
108
109error_regulator_register:
110error_get_regulator_init_data:
111	vexpress_config_func_put(reg->func);
112error_get_func:
113error_kzalloc:
114	return err;
115}
116
117static int vexpress_regulator_remove(struct platform_device *pdev)
118{
119	struct vexpress_regulator *reg = platform_get_drvdata(pdev);
120
121	vexpress_config_func_put(reg->func);
122
123	return 0;
124}
125
126static struct of_device_id vexpress_regulator_of_match[] = {
127	{ .compatible = "arm,vexpress-volt", },
128	{ }
129};
130
131static struct platform_driver vexpress_regulator_driver = {
132	.probe = vexpress_regulator_probe,
133	.remove = vexpress_regulator_remove,
134	.driver	= {
135		.name = DRVNAME,
136		.owner = THIS_MODULE,
137		.of_match_table = vexpress_regulator_of_match,
138	},
139};
140
141module_platform_driver(vexpress_regulator_driver);
142
143MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
144MODULE_DESCRIPTION("Versatile Express regulator");
145MODULE_LICENSE("GPL");
146MODULE_ALIAS("platform:vexpress-regulator");