LXR linux/drivers/regulator/fixed.c

   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};
  38
  39
  40/**
  41 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
  42 * @dev: device requesting for fixed_voltage_config
  43 * @desc: regulator description
  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                            const struct regulator_desc *desc)
  52{
  53        struct fixed_voltage_config *config;
  54        struct device_node *np = dev->of_node;
  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, desc);
  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        of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
  96
  97        config->enable_high = of_property_read_bool(np, "enable-active-high");
  98        config->gpio_is_open_drain = of_property_read_bool(np,
  99                                                           "gpio-open-drain");
 100
 101        if (of_find_property(np, "vin-supply", NULL))
 102                config->input_supply = "vin";
 103
 104        return config;
 105}
 106
 107static struct regulator_ops fixed_voltage_ops = {
 108};
 109
 110static int reg_fixed_voltage_probe(struct platform_device *pdev)
 111{
 112        struct fixed_voltage_config *config;
 113        struct fixed_voltage_data *drvdata;
 114        struct regulator_config cfg = { };
 115        int ret;
 116
 117        drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 118                               GFP_KERNEL);
 119        if (!drvdata)
 120                return -ENOMEM;
 121
 122        if (pdev->dev.of_node) {
 123                config = of_get_fixed_voltage_config(&pdev->dev,
 124                                                     &drvdata->desc);
 125                if (IS_ERR(config))
 126                        return PTR_ERR(config);
 127        } else {
 128                config = dev_get_platdata(&pdev->dev);
 129        }
 130
 131        if (!config)
 132                return -ENOMEM;
 133
 134        drvdata->desc.name = devm_kstrdup(&pdev->dev,
 135                                          config->supply_name,
 136                                          GFP_KERNEL);
 137        if (drvdata->desc.name == NULL) {
 138                dev_err(&pdev->dev, "Failed to allocate supply name\n");
 139                return -ENOMEM;
 140        }
 141        drvdata->desc.type = REGULATOR_VOLTAGE;
 142        drvdata->desc.owner = THIS_MODULE;
 143        drvdata->desc.ops = &fixed_voltage_ops;
 144
 145        drvdata->desc.enable_time = config->startup_delay;
 146
 147        if (config->input_supply) {
 148                drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 149                                            config->input_supply,
 150                                            GFP_KERNEL);
 151                if (!drvdata->desc.supply_name) {
 152                        dev_err(&pdev->dev,
 153                                "Failed to allocate input supply\n");
 154                        return -ENOMEM;
 155                }
 156        }
 157
 158        if (config->microvolts)
 159                drvdata->desc.n_voltages = 1;
 160
 161        drvdata->desc.fixed_uV = config->microvolts;
 162
 163        if (gpio_is_valid(config->gpio)) {
 164                cfg.ena_gpio = config->gpio;
 165                if (pdev->dev.of_node)
 166                        cfg.ena_gpio_initialized = true;
 167        }
 168        cfg.ena_gpio_invert = !config->enable_high;
 169        if (config->enabled_at_boot) {
 170                if (config->enable_high)
 171                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 172                else
 173                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 174        } else {
 175                if (config->enable_high)
 176                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 177                else
 178                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 179        }
 180        if (config->gpio_is_open_drain)
 181                cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
 182
 183        cfg.dev = &pdev->dev;
 184        cfg.init_data = config->init_data;
 185        cfg.driver_data = drvdata;
 186        cfg.of_node = pdev->dev.of_node;
 187
 188        drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 189                                               &cfg);
 190        if (IS_ERR(drvdata->dev)) {
 191                ret = PTR_ERR(drvdata->dev);
 192                dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 193                return ret;
 194        }
 195
 196        platform_set_drvdata(pdev, drvdata);
 197
 198        dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 199                drvdata->desc.fixed_uV);
 200
 201        return 0;
 202}
 203
 204#if defined(CONFIG_OF)
 205static const struct of_device_id fixed_of_match[] = {
 206        { .compatible = "regulator-fixed", },
 207        {},
 208};
 209MODULE_DEVICE_TABLE(of, fixed_of_match);
 210#endif
 211
 212static struct platform_driver regulator_fixed_voltage_driver = {
 213        .probe          = reg_fixed_voltage_probe,
 214        .driver         = {
 215                .name           = "reg-fixed-voltage",
 216                .of_match_table = of_match_ptr(fixed_of_match),
 217        },
 218};
 219
 220static int __init regulator_fixed_voltage_init(void)
 221{
 222        return platform_driver_register(&regulator_fixed_voltage_driver);
 223}
 224subsys_initcall(regulator_fixed_voltage_init);
 225
 226static void __exit regulator_fixed_voltage_exit(void)
 227{
 228        platform_driver_unregister(&regulator_fixed_voltage_driver);
 229}
 230module_exit(regulator_fixed_voltage_exit);
 231
 232MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 233MODULE_DESCRIPTION("Fixed voltage regulator");
 234MODULE_LICENSE("GPL");
 235MODULE_ALIAS("platform:reg-fixed-voltage");
 236