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
  34 struct 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  */
  49 static struct fixed_voltage_config *
  50 of_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
 111 static 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
 121 static 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
 132 static struct regulator_ops fixed_voltage_ops = {
 133         .get_voltage = fixed_voltage_get_voltage,
 134         .list_voltage = fixed_voltage_list_voltage,
 135 };
 136
 137 static 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 = dev_get_platdata(&pdev->dev);
 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
 229 err_input:
 230         kfree(drvdata->desc.supply_name);
 231 err_name:
 232         kfree(drvdata->desc.name);
 233 err:
 234         return ret;
 235 }
 236
 237 static 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)
 249 static const struct of_device_id fixed_of_match[] = {
 250         { .compatible = "regulator-fixed", },
 251         {},
 252 };
 253 MODULE_DEVICE_TABLE(of, fixed_of_match);
 254 #endif
 255
 256 static 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
 266 static int __init regulator_fixed_voltage_init(void)
 267 {
 268         return platform_driver_register(&regulator_fixed_voltage_driver);
 269 }
 270 subsys_initcall(regulator_fixed_voltage_init);
 271
 272 static void __exit regulator_fixed_voltage_exit(void)
 273 {
 274         platform_driver_unregister(&regulator_fixed_voltage_driver);
 275 }
 276 module_exit(regulator_fixed_voltage_exit);
 277
 278 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 279 MODULE_DESCRIPTION("Fixed voltage regulator");
 280 MODULE_LICENSE("GPL");
 281 MODULE_ALIAS("platform:reg-fixed-voltage");