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/delay.h>
  29 #include <linux/slab.h>
  30 #include <linux/of.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/regulator/of_regulator.h>
  33 #include <linux/regulator/machine.h>
  34
  35 struct fixed_voltage_data {
  36         struct regulator_desc desc;
  37         struct regulator_dev *dev;
  38         int microvolts;
  39         int gpio;
  40         unsigned startup_delay;
  41         bool enable_high;
  42         bool is_enabled;
  43 };
  44
  45
  46 /**
  47  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
  48  * @dev: device requesting for fixed_voltage_config
  49  *
  50  * Populates fixed_voltage_config structure by extracting data from device
  51  * tree node, returns a pointer to the populated structure of NULL if memory
  52  * alloc fails.
  53  */
  54 static struct fixed_voltage_config *
  55 of_get_fixed_voltage_config(struct device *dev)
  56 {
  57         struct fixed_voltage_config *config;
  58         struct device_node *np = dev->of_node;
  59         const __be32 *delay;
  60         struct regulator_init_data *init_data;
  61
  62         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
  63                                                                  GFP_KERNEL);
  64         if (!config)
  65                 return NULL;
  66
  67         config->init_data = of_get_regulator_init_data(dev, dev->of_node);
  68         if (!config->init_data)
  69                 return NULL;
  70
  71         init_data = config->init_data;
  72         init_data->constraints.apply_uV = 0;
  73
  74         config->supply_name = init_data->constraints.name;
  75         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
  76                 config->microvolts = init_data->constraints.min_uV;
  77         } else {
  78                 dev_err(dev,
  79                          "Fixed regulator specified with variable voltages\n");
  80                 return NULL;
  81         }
  82
  83         if (init_data->constraints.boot_on)
  84                 config->enabled_at_boot = true;
  85
  86         config->gpio = of_get_named_gpio(np, "gpio", 0);
  87         delay = of_get_property(np, "startup-delay-us", NULL);
  88         if (delay)
  89                 config->startup_delay = be32_to_cpu(*delay);
  90
  91         if (of_find_property(np, "enable-active-high", NULL))
  92                 config->enable_high = true;
  93
  94         return config;
  95 }
  96
  97 static int fixed_voltage_is_enabled(struct regulator_dev *dev)
  98 {
  99         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 100
 101         return data->is_enabled;
 102 }
 103
 104 static int fixed_voltage_enable(struct regulator_dev *dev)
 105 {
 106         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 107
 108         if (gpio_is_valid(data->gpio)) {
 109                 gpio_set_value_cansleep(data->gpio, data->enable_high);
 110                 data->is_enabled = true;
 111         }
 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         if (gpio_is_valid(data->gpio)) {
 121                 gpio_set_value_cansleep(data->gpio, !data->enable_high);
 122                 data->is_enabled = false;
 123         }
 124
 125         return 0;
 126 }
 127
 128 static int fixed_voltage_enable_time(struct regulator_dev *dev)
 129 {
 130         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 131
 132         return data->startup_delay;
 133 }
 134
 135 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
 136 {
 137         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 138
 139         if (data->microvolts)
 140                 return data->microvolts;
 141         else
 142                 return -EINVAL;
 143 }
 144
 145 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
 146                                       unsigned selector)
 147 {
 148         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 149
 150         if (selector != 0)
 151                 return -EINVAL;
 152
 153         return data->microvolts;
 154 }
 155
 156 static struct regulator_ops fixed_voltage_ops = {
 157         .is_enabled = fixed_voltage_is_enabled,
 158         .enable = fixed_voltage_enable,
 159         .disable = fixed_voltage_disable,
 160         .enable_time = fixed_voltage_enable_time,
 161         .get_voltage = fixed_voltage_get_voltage,
 162         .list_voltage = fixed_voltage_list_voltage,
 163 };
 164
 165 static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
 166 {
 167         struct fixed_voltage_config *config;
 168         struct fixed_voltage_data *drvdata;
 169         int ret;
 170
 171         if (pdev->dev.of_node)
 172                 config = of_get_fixed_voltage_config(&pdev->dev);
 173         else
 174                 config = pdev->dev.platform_data;
 175
 176         if (!config)
 177                 return -ENOMEM;
 178
 179         drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
 180         if (drvdata == NULL) {
 181                 dev_err(&pdev->dev, "Failed to allocate device data\n");
 182                 ret = -ENOMEM;
 183                 goto err;
 184         }
 185
 186         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 187         if (drvdata->desc.name == NULL) {
 188                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 189                 ret = -ENOMEM;
 190                 goto err;
 191         }
 192         drvdata->desc.type = REGULATOR_VOLTAGE;
 193         drvdata->desc.owner = THIS_MODULE;
 194         drvdata->desc.ops = &fixed_voltage_ops;
 195         drvdata->desc.n_voltages = 1;
 196
 197         drvdata->microvolts = config->microvolts;
 198         drvdata->gpio = config->gpio;
 199         drvdata->startup_delay = config->startup_delay;
 200
 201         if (gpio_is_valid(config->gpio)) {
 202                 drvdata->enable_high = config->enable_high;
 203
 204                 /* FIXME: Remove below print warning
 205                  *
 206                  * config->gpio must be set to -EINVAL by platform code if
 207                  * GPIO control is not required. However, early adopters
 208                  * not requiring GPIO control may forget to initialize
 209                  * config->gpio to -EINVAL. This will cause GPIO 0 to be used
 210                  * for GPIO control.
 211                  *
 212                  * This warning will be removed once there are a couple of users
 213                  * for this driver.
 214                  */
 215                 if (!config->gpio)
 216                         dev_warn(&pdev->dev,
 217                                 "using GPIO 0 for regulator enable control\n");
 218
 219                 ret = gpio_request(config->gpio, config->supply_name);
 220                 if (ret) {
 221                         dev_err(&pdev->dev,
 222                            "Could not obtain regulator enable GPIO %d: %d\n",
 223                                                         config->gpio, ret);
 224                         goto err_name;
 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
 234                 ret = gpio_direction_output(config->gpio, ret);
 235                 if (ret) {
 236                         dev_err(&pdev->dev,
 237                            "Could not configure regulator enable GPIO %d direction: %d\n",
 238                                                         config->gpio, ret);
 239                         goto err_gpio;
 240                 }
 241
 242         } else {
 243                 /* Regulator without GPIO control is considered
 244                  * always enabled
 245                  */
 246                 drvdata->is_enabled = true;
 247         }
 248
 249         drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
 250                                           config->init_data, drvdata,
 251                                           pdev->dev.of_node);
 252         if (IS_ERR(drvdata->dev)) {
 253                 ret = PTR_ERR(drvdata->dev);
 254                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 255                 goto err_gpio;
 256         }
 257
 258         platform_set_drvdata(pdev, drvdata);
 259
 260         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 261                 drvdata->microvolts);
 262
 263         return 0;
 264
 265 err_gpio:
 266         if (gpio_is_valid(config->gpio))
 267                 gpio_free(config->gpio);
 268 err_name:
 269         kfree(drvdata->desc.name);
 270 err:
 271         kfree(drvdata);
 272         return ret;
 273 }
 274
 275 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
 276 {
 277         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
 278
 279         regulator_unregister(drvdata->dev);
 280         if (gpio_is_valid(drvdata->gpio))
 281                 gpio_free(drvdata->gpio);
 282         kfree(drvdata->desc.name);
 283         kfree(drvdata);
 284
 285         return 0;
 286 }
 287
 288 #if defined(CONFIG_OF)
 289 static const struct of_device_id fixed_of_match[] __devinitconst = {
 290         { .compatible = "regulator-fixed", },
 291         {},
 292 };
 293 MODULE_DEVICE_TABLE(of, fixed_of_match);
 294 #else
 295 #define fixed_of_match NULL
 296 #endif
 297
 298 static struct platform_driver regulator_fixed_voltage_driver = {
 299         .probe          = reg_fixed_voltage_probe,
 300         .remove         = __devexit_p(reg_fixed_voltage_remove),
 301         .driver         = {
 302                 .name           = "reg-fixed-voltage",
 303                 .owner          = THIS_MODULE,
 304                 .of_match_table = fixed_of_match,
 305         },
 306 };
 307
 308 static int __init regulator_fixed_voltage_init(void)
 309 {
 310         return platform_driver_register(&regulator_fixed_voltage_driver);
 311 }
 312 subsys_initcall(regulator_fixed_voltage_init);
 313
 314 static void __exit regulator_fixed_voltage_exit(void)
 315 {
 316         platform_driver_unregister(&regulator_fixed_voltage_driver);
 317 }
 318 module_exit(regulator_fixed_voltage_exit);
 319
 320 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 321 MODULE_DESCRIPTION("Fixed voltage regulator");
 322 MODULE_LICENSE("GPL");
 323 MODULE_ALIAS("platform:reg-fixed-voltage");