linux/drivers/regulator/vexpress.c
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   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 = regulator_register(&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        regulator_unregister(reg->regdev);
 123
 124        return 0;
 125}
 126
 127static struct of_device_id vexpress_regulator_of_match[] = {
 128        { .compatible = "arm,vexpress-volt", },
 129        { }
 130};
 131
 132static struct platform_driver vexpress_regulator_driver = {
 133        .probe = vexpress_regulator_probe,
 134        .remove = vexpress_regulator_remove,
 135        .driver = {
 136                .name = DRVNAME,
 137                .owner = THIS_MODULE,
 138                .of_match_table = vexpress_regulator_of_match,
 139        },
 140};
 141
 142module_platform_driver(vexpress_regulator_driver);
 143
 144MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
 145MODULE_DESCRIPTION("Versatile Express regulator");
 146MODULE_LICENSE("GPL");
 147MODULE_ALIAS("platform:vexpress-regulator");
 148
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