linux/drivers/regulator/fixed.c
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   1/*
   2 * fixed.c
   3 *
   4 * Copyright 2008 Wolfson Microelectronics PLC.
   5 *
   6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7 *
   8 * Copyright (c) 2009 Nokia Corporation
   9 * Roger Quadros <ext-roger.quadros@nokia.com>
  10 *
  11 * This program is free software; you can redistribute it and/or
  12 * modify it under the terms of the GNU General Public License as
  13 * published by the Free Software Foundation; either version 2 of the
  14 * License, or (at your option) any later version.
  15 *
  16 * This is useful for systems with mixed controllable and
  17 * non-controllable regulators, as well as for allowing testing on
  18 * systems with no controllable regulators.
  19 */
  20
  21#include <linux/err.h>
  22#include <linux/mutex.h>
  23#include <linux/module.h>
  24#include <linux/platform_device.h>
  25#include <linux/regulator/driver.h>
  26#include <linux/regulator/fixed.h>
  27#include <linux/gpio.h>
  28#include <linux/slab.h>
  29#include <linux/of.h>
  30#include <linux/of_gpio.h>
  31#include <linux/regulator/of_regulator.h>
  32#include <linux/regulator/machine.h>
  33
  34struct fixed_voltage_data {
  35        struct regulator_desc desc;
  36        struct regulator_dev *dev;
  37        int microvolts;
  38};
  39
  40
  41/**
  42 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
  43 * @dev: device requesting for fixed_voltage_config
  44 *
  45 * Populates fixed_voltage_config structure by extracting data from device
  46 * tree node, returns a pointer to the populated structure of NULL if memory
  47 * alloc fails.
  48 */
  49static struct fixed_voltage_config *
  50of_get_fixed_voltage_config(struct device *dev)
  51{
  52        struct fixed_voltage_config *config;
  53        struct device_node *np = dev->of_node;
  54        const __be32 *delay;
  55        struct regulator_init_data *init_data;
  56
  57        config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
  58                                                                 GFP_KERNEL);
  59        if (!config)
  60                return ERR_PTR(-ENOMEM);
  61
  62        config->init_data = of_get_regulator_init_data(dev, dev->of_node);
  63        if (!config->init_data)
  64                return ERR_PTR(-EINVAL);
  65
  66        init_data = config->init_data;
  67        init_data->constraints.apply_uV = 0;
  68
  69        config->supply_name = init_data->constraints.name;
  70        if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
  71                config->microvolts = init_data->constraints.min_uV;
  72        } else {
  73                dev_err(dev,
  74                         "Fixed regulator specified with variable voltages\n");
  75                return ERR_PTR(-EINVAL);
  76        }
  77
  78        if (init_data->constraints.boot_on)
  79                config->enabled_at_boot = true;
  80
  81        config->gpio = of_get_named_gpio(np, "gpio", 0);
  82        /*
  83         * of_get_named_gpio() currently returns ENODEV rather than
  84         * EPROBE_DEFER. This code attempts to be compatible with both
  85         * for now; the ENODEV check can be removed once the API is fixed.
  86         * of_get_named_gpio() doesn't differentiate between a missing
  87         * property (which would be fine here, since the GPIO is optional)
  88         * and some other error. Patches have been posted for both issues.
  89         * Once they are check in, we should replace this with:
  90         * if (config->gpio < 0 && config->gpio != -ENOENT)
  91         */
  92        if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER))
  93                return ERR_PTR(-EPROBE_DEFER);
  94
  95        delay = of_get_property(np, "startup-delay-us", NULL);
  96        if (delay)
  97                config->startup_delay = be32_to_cpu(*delay);
  98
  99        if (of_find_property(np, "enable-active-high", NULL))
 100                config->enable_high = true;
 101
 102        if (of_find_property(np, "gpio-open-drain", NULL))
 103                config->gpio_is_open_drain = true;
 104
 105        if (of_find_property(np, "vin-supply", NULL))
 106                config->input_supply = "vin";
 107
 108        return config;
 109}
 110
 111static int fixed_voltage_get_voltage(struct regulator_dev *dev)
 112{
 113        struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 114
 115        if (data->microvolts)
 116                return data->microvolts;
 117        else
 118                return -EINVAL;
 119}
 120
 121static int fixed_voltage_list_voltage(struct regulator_dev *dev,
 122                                      unsigned selector)
 123{
 124        struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 125
 126        if (selector != 0)
 127                return -EINVAL;
 128
 129        return data->microvolts;
 130}
 131
 132static struct regulator_ops fixed_voltage_ops = {
 133        .get_voltage = fixed_voltage_get_voltage,
 134        .list_voltage = fixed_voltage_list_voltage,
 135};
 136
 137static int reg_fixed_voltage_probe(struct platform_device *pdev)
 138{
 139        struct fixed_voltage_config *config;
 140        struct fixed_voltage_data *drvdata;
 141        struct regulator_config cfg = { };
 142        int ret;
 143
 144        if (pdev->dev.of_node) {
 145                config = of_get_fixed_voltage_config(&pdev->dev);
 146                if (IS_ERR(config))
 147                        return PTR_ERR(config);
 148        } else {
 149                config = pdev->dev.platform_data;
 150        }
 151
 152        if (!config)
 153                return -ENOMEM;
 154
 155        drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 156                               GFP_KERNEL);
 157        if (drvdata == NULL) {
 158                dev_err(&pdev->dev, "Failed to allocate device data\n");
 159                ret = -ENOMEM;
 160                goto err;
 161        }
 162
 163        drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 164        if (drvdata->desc.name == NULL) {
 165                dev_err(&pdev->dev, "Failed to allocate supply name\n");
 166                ret = -ENOMEM;
 167                goto err;
 168        }
 169        drvdata->desc.type = REGULATOR_VOLTAGE;
 170        drvdata->desc.owner = THIS_MODULE;
 171        drvdata->desc.ops = &fixed_voltage_ops;
 172
 173        drvdata->desc.enable_time = config->startup_delay;
 174
 175        if (config->input_supply) {
 176                drvdata->desc.supply_name = kstrdup(config->input_supply,
 177                                                        GFP_KERNEL);
 178                if (!drvdata->desc.supply_name) {
 179                        dev_err(&pdev->dev,
 180                                "Failed to allocate input supply\n");
 181                        ret = -ENOMEM;
 182                        goto err_name;
 183                }
 184        }
 185
 186        if (config->microvolts)
 187                drvdata->desc.n_voltages = 1;
 188
 189        drvdata->microvolts = config->microvolts;
 190
 191        if (config->gpio >= 0)
 192                cfg.ena_gpio = config->gpio;
 193        cfg.ena_gpio_invert = !config->enable_high;
 194        if (config->enabled_at_boot) {
 195                if (config->enable_high) {
 196                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 197                } else {
 198                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 199                }
 200        } else {
 201                if (config->enable_high) {
 202                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 203                } else {
 204                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 205                }
 206        }
 207        if (config->gpio_is_open_drain)
 208                cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
 209
 210        cfg.dev = &pdev->dev;
 211        cfg.init_data = config->init_data;
 212        cfg.driver_data = drvdata;
 213        cfg.of_node = pdev->dev.of_node;
 214
 215        drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 216        if (IS_ERR(drvdata->dev)) {
 217                ret = PTR_ERR(drvdata->dev);
 218                dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 219                goto err_input;
 220        }
 221
 222        platform_set_drvdata(pdev, drvdata);
 223
 224        dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 225                drvdata->microvolts);
 226
 227        return 0;
 228
 229err_input:
 230        kfree(drvdata->desc.supply_name);
 231err_name:
 232        kfree(drvdata->desc.name);
 233err:
 234        return ret;
 235}
 236
 237static int reg_fixed_voltage_remove(struct platform_device *pdev)
 238{
 239        struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
 240
 241        regulator_unregister(drvdata->dev);
 242        kfree(drvdata->desc.supply_name);
 243        kfree(drvdata->desc.name);
 244
 245        return 0;
 246}
 247
 248#if defined(CONFIG_OF)
 249static const struct of_device_id fixed_of_match[] = {
 250        { .compatible = "regulator-fixed", },
 251        {},
 252};
 253MODULE_DEVICE_TABLE(of, fixed_of_match);
 254#endif
 255
 256static struct platform_driver regulator_fixed_voltage_driver = {
 257        .probe          = reg_fixed_voltage_probe,
 258        .remove         = reg_fixed_voltage_remove,
 259        .driver         = {
 260                .name           = "reg-fixed-voltage",
 261                .owner          = THIS_MODULE,
 262                .of_match_table = of_match_ptr(fixed_of_match),
 263        },
 264};
 265
 266static int __init regulator_fixed_voltage_init(void)
 267{
 268        return platform_driver_register(&regulator_fixed_voltage_driver);
 269}
 270subsys_initcall(regulator_fixed_voltage_init);
 271
 272static void __exit regulator_fixed_voltage_exit(void)
 273{
 274        platform_driver_unregister(&regulator_fixed_voltage_driver);
 275}
 276module_exit(regulator_fixed_voltage_exit);
 277
 278MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 279MODULE_DESCRIPTION("Fixed voltage regulator");
 280MODULE_LICENSE("GPL");
 281MODULE_ALIAS("platform:reg-fixed-voltage");
 282
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