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         int gpio;
  39         unsigned startup_delay;
  40         bool enable_high;
  41         bool is_enabled;
  42 };
  43
  44
  45 /**
  46  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
  47  * @dev: device requesting for fixed_voltage_config
  48  *
  49  * Populates fixed_voltage_config structure by extracting data from device
  50  * tree node, returns a pointer to the populated structure of NULL if memory
  51  * alloc fails.
  52  */
  53 static struct fixed_voltage_config *
  54 of_get_fixed_voltage_config(struct device *dev)
  55 {
  56         struct fixed_voltage_config *config;
  57         struct device_node *np = dev->of_node;
  58         const __be32 *delay;
  59         struct regulator_init_data *init_data;
  60
  61         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
  62                                                                  GFP_KERNEL);
  63         if (!config)
  64                 return NULL;
  65
  66         config->init_data = of_get_regulator_init_data(dev, dev->of_node);
  67         if (!config->init_data)
  68                 return NULL;
  69
  70         init_data = config->init_data;
  71         init_data->constraints.apply_uV = 0;
  72
  73         config->supply_name = init_data->constraints.name;
  74         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
  75                 config->microvolts = init_data->constraints.min_uV;
  76         } else {
  77                 dev_err(dev,
  78                          "Fixed regulator specified with variable voltages\n");
  79                 return NULL;
  80         }
  81
  82         if (init_data->constraints.boot_on)
  83                 config->enabled_at_boot = true;
  84
  85         config->gpio = of_get_named_gpio(np, "gpio", 0);
  86         delay = of_get_property(np, "startup-delay-us", NULL);
  87         if (delay)
  88                 config->startup_delay = be32_to_cpu(*delay);
  89
  90         if (of_find_property(np, "enable-active-high", NULL))
  91                 config->enable_high = true;
  92
  93         if (of_find_property(np, "gpio-open-drain", NULL))
  94                 config->gpio_is_open_drain = true;
  95
  96         return config;
  97 }
  98
  99 static int fixed_voltage_is_enabled(struct regulator_dev *dev)
 100 {
 101         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 102
 103         return data->is_enabled;
 104 }
 105
 106 static int fixed_voltage_enable(struct regulator_dev *dev)
 107 {
 108         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 109
 110         gpio_set_value_cansleep(data->gpio, data->enable_high);
 111         data->is_enabled = true;
 112
 113         return 0;
 114 }
 115
 116 static int fixed_voltage_disable(struct regulator_dev *dev)
 117 {
 118         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 119
 120         gpio_set_value_cansleep(data->gpio, !data->enable_high);
 121         data->is_enabled = false;
 122
 123         return 0;
 124 }
 125
 126 static int fixed_voltage_enable_time(struct regulator_dev *dev)
 127 {
 128         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 129
 130         return data->startup_delay;
 131 }
 132
 133 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
 134 {
 135         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 136
 137         if (data->microvolts)
 138                 return data->microvolts;
 139         else
 140                 return -EINVAL;
 141 }
 142
 143 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
 144                                       unsigned selector)
 145 {
 146         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 147
 148         if (selector != 0)
 149                 return -EINVAL;
 150
 151         return data->microvolts;
 152 }
 153
 154 static struct regulator_ops fixed_voltage_gpio_ops = {
 155         .is_enabled = fixed_voltage_is_enabled,
 156         .enable = fixed_voltage_enable,
 157         .disable = fixed_voltage_disable,
 158         .enable_time = fixed_voltage_enable_time,
 159         .get_voltage = fixed_voltage_get_voltage,
 160         .list_voltage = fixed_voltage_list_voltage,
 161 };
 162
 163 static struct regulator_ops fixed_voltage_ops = {
 164         .get_voltage = fixed_voltage_get_voltage,
 165         .list_voltage = fixed_voltage_list_voltage,
 166 };
 167
 168 static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
 169 {
 170         struct fixed_voltage_config *config;
 171         struct fixed_voltage_data *drvdata;
 172         struct regulator_config cfg = { };
 173         int ret;
 174
 175         if (pdev->dev.of_node)
 176                 config = of_get_fixed_voltage_config(&pdev->dev);
 177         else
 178                 config = pdev->dev.platform_data;
 179
 180         if (!config)
 181                 return -ENOMEM;
 182
 183         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 184                                GFP_KERNEL);
 185         if (drvdata == NULL) {
 186                 dev_err(&pdev->dev, "Failed to allocate device data\n");
 187                 ret = -ENOMEM;
 188                 goto err;
 189         }
 190
 191         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 192         if (drvdata->desc.name == NULL) {
 193                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 194                 ret = -ENOMEM;
 195                 goto err;
 196         }
 197         drvdata->desc.type = REGULATOR_VOLTAGE;
 198         drvdata->desc.owner = THIS_MODULE;
 199
 200         if (config->microvolts)
 201                 drvdata->desc.n_voltages = 1;
 202
 203         drvdata->microvolts = config->microvolts;
 204         drvdata->gpio = config->gpio;
 205         drvdata->startup_delay = config->startup_delay;
 206
 207         if (gpio_is_valid(config->gpio)) {
 208                 int gpio_flag;
 209                 drvdata->enable_high = config->enable_high;
 210
 211                 /* FIXME: Remove below print warning
 212                  *
 213                  * config->gpio must be set to -EINVAL by platform code if
 214                  * GPIO control is not required. However, early adopters
 215                  * not requiring GPIO control may forget to initialize
 216                  * config->gpio to -EINVAL. This will cause GPIO 0 to be used
 217                  * for GPIO control.
 218                  *
 219                  * This warning will be removed once there are a couple of users
 220                  * for this driver.
 221                  */
 222                 if (!config->gpio)
 223                         dev_warn(&pdev->dev,
 224                                 "using GPIO 0 for regulator enable control\n");
 225
 226                 /*
 227                  * set output direction without changing state
 228                  * to prevent glitch
 229                  */
 230                 drvdata->is_enabled = config->enabled_at_boot;
 231                 ret = drvdata->is_enabled ?
 232                                 config->enable_high : !config->enable_high;
 233                 gpio_flag = ret ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
 234
 235                 if (config->gpio_is_open_drain)
 236                         gpio_flag |= GPIOF_OPEN_DRAIN;
 237
 238                 ret = gpio_request_one(config->gpio, gpio_flag,
 239                                                 config->supply_name);
 240                 if (ret) {
 241                         dev_err(&pdev->dev,
 242                            "Could not obtain regulator enable GPIO %d: %d\n",
 243                                                         config->gpio, ret);
 244                         goto err_name;
 245                 }
 246
 247                 drvdata->desc.ops = &fixed_voltage_gpio_ops;
 248
 249         } else {
 250                 drvdata->desc.ops = &fixed_voltage_ops;
 251         }
 252
 253         cfg.dev = &pdev->dev;
 254         cfg.init_data = config->init_data;
 255         cfg.driver_data = drvdata;
 256         cfg.of_node = pdev->dev.of_node;
 257
 258         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 259         if (IS_ERR(drvdata->dev)) {
 260                 ret = PTR_ERR(drvdata->dev);
 261                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 262                 goto err_gpio;
 263         }
 264
 265         platform_set_drvdata(pdev, drvdata);
 266
 267         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 268                 drvdata->microvolts);
 269
 270         return 0;
 271
 272 err_gpio:
 273         if (gpio_is_valid(config->gpio))
 274                 gpio_free(config->gpio);
 275 err_name:
 276         kfree(drvdata->desc.name);
 277 err:
 278         return ret;
 279 }
 280
 281 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
 282 {
 283         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
 284
 285         regulator_unregister(drvdata->dev);
 286         if (gpio_is_valid(drvdata->gpio))
 287                 gpio_free(drvdata->gpio);
 288         kfree(drvdata->desc.name);
 289
 290         return 0;
 291 }
 292
 293 #if defined(CONFIG_OF)
 294 static const struct of_device_id fixed_of_match[] __devinitconst = {
 295         { .compatible = "regulator-fixed", },
 296         {},
 297 };
 298 MODULE_DEVICE_TABLE(of, fixed_of_match);
 299 #else
 300 #define fixed_of_match NULL
 301 #endif
 302
 303 static struct platform_driver regulator_fixed_voltage_driver = {
 304         .probe          = reg_fixed_voltage_probe,
 305         .remove         = __devexit_p(reg_fixed_voltage_remove),
 306         .driver         = {
 307                 .name           = "reg-fixed-voltage",
 308                 .owner          = THIS_MODULE,
 309                 .of_match_table = fixed_of_match,
 310         },
 311 };
 312
 313 static int __init regulator_fixed_voltage_init(void)
 314 {
 315         return platform_driver_register(&regulator_fixed_voltage_driver);
 316 }
 317 subsys_initcall(regulator_fixed_voltage_init);
 318
 319 static void __exit regulator_fixed_voltage_exit(void)
 320 {
 321         platform_driver_unregister(&regulator_fixed_voltage_driver);
 322 }
 323 module_exit(regulator_fixed_voltage_exit);
 324
 325 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 326 MODULE_DESCRIPTION("Fixed voltage regulator");
 327 MODULE_LICENSE("GPL");
 328 MODULE_ALIAS("platform:reg-fixed-voltage");