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
  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         return config;
  94 }
  95
  96 static int fixed_voltage_is_enabled(struct regulator_dev *dev)
  97 {
  98         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
  99
 100         return data->is_enabled;
 101 }
 102
 103 static int fixed_voltage_enable(struct regulator_dev *dev)
 104 {
 105         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 106
 107         if (gpio_is_valid(data->gpio)) {
 108                 gpio_set_value_cansleep(data->gpio, data->enable_high);
 109                 data->is_enabled = true;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static int fixed_voltage_disable(struct regulator_dev *dev)
 116 {
 117         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 118
 119         if (gpio_is_valid(data->gpio)) {
 120                 gpio_set_value_cansleep(data->gpio, !data->enable_high);
 121                 data->is_enabled = false;
 122         }
 123
 124         return 0;
 125 }
 126
 127 static int fixed_voltage_enable_time(struct regulator_dev *dev)
 128 {
 129         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 130
 131         return data->startup_delay;
 132 }
 133
 134 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
 135 {
 136         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 137
 138         return data->microvolts;
 139 }
 140
 141 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
 142                                       unsigned selector)
 143 {
 144         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
 145
 146         if (selector != 0)
 147                 return -EINVAL;
 148
 149         return data->microvolts;
 150 }
 151
 152 static struct regulator_ops fixed_voltage_ops = {
 153         .is_enabled = fixed_voltage_is_enabled,
 154         .enable = fixed_voltage_enable,
 155         .disable = fixed_voltage_disable,
 156         .enable_time = fixed_voltage_enable_time,
 157         .get_voltage = fixed_voltage_get_voltage,
 158         .list_voltage = fixed_voltage_list_voltage,
 159 };
 160
 161 static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
 162 {
 163         struct fixed_voltage_config *config;
 164         struct fixed_voltage_data *drvdata;
 165         int ret;
 166
 167         if (pdev->dev.of_node)
 168                 config = of_get_fixed_voltage_config(&pdev->dev);
 169         else
 170                 config = pdev->dev.platform_data;
 171
 172         if (!config)
 173                 return -ENOMEM;
 174
 175         drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
 176         if (drvdata == NULL) {
 177                 dev_err(&pdev->dev, "Failed to allocate device data\n");
 178                 ret = -ENOMEM;
 179                 goto err;
 180         }
 181
 182         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 183         if (drvdata->desc.name == NULL) {
 184                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 185                 ret = -ENOMEM;
 186                 goto err;
 187         }
 188         drvdata->desc.type = REGULATOR_VOLTAGE;
 189         drvdata->desc.owner = THIS_MODULE;
 190         drvdata->desc.ops = &fixed_voltage_ops;
 191         drvdata->desc.n_voltages = 1;
 192
 193         drvdata->microvolts = config->microvolts;
 194         drvdata->gpio = config->gpio;
 195         drvdata->startup_delay = config->startup_delay;
 196
 197         if (gpio_is_valid(config->gpio)) {
 198                 drvdata->enable_high = config->enable_high;
 199
 200                 /* FIXME: Remove below print warning
 201                  *
 202                  * config->gpio must be set to -EINVAL by platform code if
 203                  * GPIO control is not required. However, early adopters
 204                  * not requiring GPIO control may forget to initialize
 205                  * config->gpio to -EINVAL. This will cause GPIO 0 to be used
 206                  * for GPIO control.
 207                  *
 208                  * This warning will be removed once there are a couple of users
 209                  * for this driver.
 210                  */
 211                 if (!config->gpio)
 212                         dev_warn(&pdev->dev,
 213                                 "using GPIO 0 for regulator enable control\n");
 214
 215                 ret = gpio_request(config->gpio, config->supply_name);
 216                 if (ret) {
 217                         dev_err(&pdev->dev,
 218                            "Could not obtain regulator enable GPIO %d: %d\n",
 219                                                         config->gpio, ret);
 220                         goto err_name;
 221                 }
 222
 223                 /* set output direction without changing state
 224                  * to prevent glitch
 225                  */
 226                 drvdata->is_enabled = config->enabled_at_boot;
 227                 ret = drvdata->is_enabled ?
 228                                 config->enable_high : !config->enable_high;
 229
 230                 ret = gpio_direction_output(config->gpio, ret);
 231                 if (ret) {
 232                         dev_err(&pdev->dev,
 233                            "Could not configure regulator enable GPIO %d direction: %d\n",
 234                                                         config->gpio, ret);
 235                         goto err_gpio;
 236                 }
 237
 238         } else {
 239                 /* Regulator without GPIO control is considered
 240                  * always enabled
 241                  */
 242                 drvdata->is_enabled = true;
 243         }
 244
 245         drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
 246                                           config->init_data, drvdata, NULL);
 247         if (IS_ERR(drvdata->dev)) {
 248                 ret = PTR_ERR(drvdata->dev);
 249                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 250                 goto err_gpio;
 251         }
 252
 253         platform_set_drvdata(pdev, drvdata);
 254
 255         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 256                 drvdata->microvolts);
 257
 258         return 0;
 259
 260 err_gpio:
 261         if (gpio_is_valid(config->gpio))
 262                 gpio_free(config->gpio);
 263 err_name:
 264         kfree(drvdata->desc.name);
 265 err:
 266         kfree(drvdata);
 267         return ret;
 268 }
 269
 270 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
 271 {
 272         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
 273
 274         regulator_unregister(drvdata->dev);
 275         if (gpio_is_valid(drvdata->gpio))
 276                 gpio_free(drvdata->gpio);
 277         kfree(drvdata->desc.name);
 278         kfree(drvdata);
 279
 280         return 0;
 281 }
 282
 283 #if defined(CONFIG_OF)
 284 static const struct of_device_id fixed_of_match[] __devinitconst = {
 285         { .compatible = "regulator-fixed", },
 286         {},
 287 };
 288 MODULE_DEVICE_TABLE(of, fixed_of_match);
 289 #else
 290 #define fixed_of_match NULL
 291 #endif
 292
 293 static struct platform_driver regulator_fixed_voltage_driver = {
 294         .probe          = reg_fixed_voltage_probe,
 295         .remove         = __devexit_p(reg_fixed_voltage_remove),
 296         .driver         = {
 297                 .name           = "reg-fixed-voltage",
 298                 .owner          = THIS_MODULE,
 299                 .of_match_table = fixed_of_match,
 300         },
 301 };
 302
 303 static int __init regulator_fixed_voltage_init(void)
 304 {
 305         return platform_driver_register(&regulator_fixed_voltage_driver);
 306 }
 307 subsys_initcall(regulator_fixed_voltage_init);
 308
 309 static void __exit regulator_fixed_voltage_exit(void)
 310 {
 311         platform_driver_unregister(&regulator_fixed_voltage_driver);
 312 }
 313 module_exit(regulator_fixed_voltage_exit);
 314
 315 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 316 MODULE_DESCRIPTION("Fixed voltage regulator");
 317 MODULE_LICENSE("GPL");
 318 MODULE_ALIAS("platform:reg-fixed-voltage");