drivers/regulator/gpio-regulator.c

   1 /*
   2  * gpio-regulator.c
   3  *
   4  * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
   5  *
   6  * based on fixed.c
   7  *
   8  * Copyright 2008 Wolfson Microelectronics PLC.
   9  *
  10  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  11  *
  12  * Copyright (c) 2009 Nokia Corporation
  13  * Roger Quadros <ext-roger.quadros@nokia.com>
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License as
  17  * published by the Free Software Foundation; either version 2 of the
  18  * License, or (at your option) any later version.
  19  *
  20  * This is useful for systems with mixed controllable and
  21  * non-controllable regulators, as well as for allowing testing on
  22  * systems with no controllable regulators.
  23  */
  24
  25 #include <linux/err.h>
  26 #include <linux/mutex.h>
  27 #include <linux/module.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/regulator/driver.h>
  30 #include <linux/regulator/machine.h>
  31 #include <linux/regulator/gpio-regulator.h>
  32 #include <linux/gpio.h>
  33 #include <linux/slab.h>
  34
  35 struct gpio_regulator_data {
  36         struct regulator_desc desc;
  37         struct regulator_dev *dev;
  38
  39         int enable_gpio;
  40         bool enable_high;
  41         bool is_enabled;
  42         unsigned startup_delay;
  43
  44         struct gpio *gpios;
  45         int nr_gpios;
  46
  47         struct gpio_regulator_state *states;
  48         int nr_states;
  49
  50         int state;
  51 };
  52
  53 static int gpio_regulator_is_enabled(struct regulator_dev *dev)
  54 {
  55         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  56
  57         return data->is_enabled;
  58 }
  59
  60 static int gpio_regulator_enable(struct regulator_dev *dev)
  61 {
  62         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  63
  64         if (gpio_is_valid(data->enable_gpio)) {
  65                 gpio_set_value_cansleep(data->enable_gpio, data->enable_high);
  66                 data->is_enabled = true;
  67         }
  68
  69         return 0;
  70 }
  71
  72 static int gpio_regulator_disable(struct regulator_dev *dev)
  73 {
  74         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  75
  76         if (gpio_is_valid(data->enable_gpio)) {
  77                 gpio_set_value_cansleep(data->enable_gpio, !data->enable_high);
  78                 data->is_enabled = false;
  79         }
  80
  81         return 0;
  82 }
  83
  84 static int gpio_regulator_enable_time(struct regulator_dev *dev)
  85 {
  86         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  87
  88         return data->startup_delay;
  89 }
  90
  91 static int gpio_regulator_get_value(struct regulator_dev *dev)
  92 {
  93         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  94         int ptr;
  95
  96         for (ptr = 0; ptr < data->nr_states; ptr++)
  97                 if (data->states[ptr].gpios == data->state)
  98                         return data->states[ptr].value;
  99
 100         return -EINVAL;
 101 }
 102
 103 static int gpio_regulator_set_value(struct regulator_dev *dev,
 104                                         int min, int max)
 105 {
 106         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 107         int ptr, target = 0, state, best_val = INT_MAX;
 108
 109         for (ptr = 0; ptr < data->nr_states; ptr++)
 110                 if (data->states[ptr].value < best_val &&
 111                     data->states[ptr].value >= min &&
 112                     data->states[ptr].value <= max) {
 113                         target = data->states[ptr].gpios;
 114                         best_val = data->states[ptr].value;
 115                 }
 116
 117         if (best_val == INT_MAX)
 118                 return -EINVAL;
 119
 120         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 121                 state = (target & (1 << ptr)) >> ptr;
 122                 gpio_set_value(data->gpios[ptr].gpio, state);
 123         }
 124         data->state = target;
 125
 126         return 0;
 127 }
 128
 129 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
 130                                         int min_uV, int max_uV,
 131                                         unsigned *selector)
 132 {
 133         return gpio_regulator_set_value(dev, min_uV, max_uV);
 134 }
 135
 136 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
 137                                       unsigned selector)
 138 {
 139         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 140
 141         if (selector >= data->nr_states)
 142                 return -EINVAL;
 143
 144         return data->states[selector].value;
 145 }
 146
 147 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
 148                                         int min_uA, int max_uA)
 149 {
 150         return gpio_regulator_set_value(dev, min_uA, max_uA);
 151 }
 152
 153 static struct regulator_ops gpio_regulator_voltage_ops = {
 154         .is_enabled = gpio_regulator_is_enabled,
 155         .enable = gpio_regulator_enable,
 156         .disable = gpio_regulator_disable,
 157         .enable_time = gpio_regulator_enable_time,
 158         .get_voltage = gpio_regulator_get_value,
 159         .set_voltage = gpio_regulator_set_voltage,
 160         .list_voltage = gpio_regulator_list_voltage,
 161 };
 162
 163 static struct regulator_ops gpio_regulator_current_ops = {
 164         .is_enabled = gpio_regulator_is_enabled,
 165         .enable = gpio_regulator_enable,
 166         .disable = gpio_regulator_disable,
 167         .enable_time = gpio_regulator_enable_time,
 168         .get_current_limit = gpio_regulator_get_value,
 169         .set_current_limit = gpio_regulator_set_current_limit,
 170 };
 171
 172 static int __devinit gpio_regulator_probe(struct platform_device *pdev)
 173 {
 174         struct gpio_regulator_config *config = pdev->dev.platform_data;
 175         struct gpio_regulator_data *drvdata;
 176         struct regulator_config cfg = { };
 177         int ptr, ret, state;
 178
 179         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
 180                                GFP_KERNEL);
 181         if (drvdata == NULL) {
 182                 dev_err(&pdev->dev, "Failed to allocate device data\n");
 183                 return -ENOMEM;
 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
 193         drvdata->gpios = kmemdup(config->gpios,
 194                                  config->nr_gpios * sizeof(struct gpio),
 195                                  GFP_KERNEL);
 196         if (drvdata->gpios == NULL) {
 197                 dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 198                 ret = -ENOMEM;
 199                 goto err_name;
 200         }
 201
 202         drvdata->states = kmemdup(config->states,
 203                                   config->nr_states *
 204                                          sizeof(struct gpio_regulator_state),
 205                                   GFP_KERNEL);
 206         if (drvdata->states == NULL) {
 207                 dev_err(&pdev->dev, "Failed to allocate state data\n");
 208                 ret = -ENOMEM;
 209                 goto err_memgpio;
 210         }
 211         drvdata->nr_states = config->nr_states;
 212
 213         drvdata->desc.owner = THIS_MODULE;
 214
 215         /* handle regulator type*/
 216         switch (config->type) {
 217         case REGULATOR_VOLTAGE:
 218                 drvdata->desc.type = REGULATOR_VOLTAGE;
 219                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
 220                 drvdata->desc.n_voltages = config->nr_states;
 221                 break;
 222         case REGULATOR_CURRENT:
 223                 drvdata->desc.type = REGULATOR_CURRENT;
 224                 drvdata->desc.ops = &gpio_regulator_current_ops;
 225                 break;
 226         default:
 227                 dev_err(&pdev->dev, "No regulator type set\n");
 228                 ret = -EINVAL;
 229                 goto err_memgpio;
 230                 break;
 231         }
 232
 233         drvdata->enable_gpio = config->enable_gpio;
 234         drvdata->startup_delay = config->startup_delay;
 235
 236         if (gpio_is_valid(config->enable_gpio)) {
 237                 drvdata->enable_high = config->enable_high;
 238
 239                 ret = gpio_request(config->enable_gpio, config->supply_name);
 240                 if (ret) {
 241                         dev_err(&pdev->dev,
 242                            "Could not obtain regulator enable GPIO %d: %d\n",
 243                                                 config->enable_gpio, ret);
 244                         goto err_memstate;
 245                 }
 246
 247                 /* set output direction without changing state
 248                  * to prevent glitch
 249                  */
 250                 if (config->enabled_at_boot) {
 251                         drvdata->is_enabled = true;
 252                         ret = gpio_direction_output(config->enable_gpio,
 253                                                     config->enable_high);
 254                 } else {
 255                         drvdata->is_enabled = false;
 256                         ret = gpio_direction_output(config->enable_gpio,
 257                                                     !config->enable_high);
 258                 }
 259
 260                 if (ret) {
 261                         dev_err(&pdev->dev,
 262                            "Could not configure regulator enable GPIO %d direction: %d\n",
 263                                                 config->enable_gpio, ret);
 264                         goto err_enablegpio;
 265                 }
 266         } else {
 267                 /* Regulator without GPIO control is considered
 268                  * always enabled
 269                  */
 270                 drvdata->is_enabled = true;
 271         }
 272
 273         drvdata->nr_gpios = config->nr_gpios;
 274         ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 275         if (ret) {
 276                 dev_err(&pdev->dev,
 277                    "Could not obtain regulator setting GPIOs: %d\n", ret);
 278                 goto err_enablegpio;
 279         }
 280
 281         /* build initial state from gpio init data. */
 282         state = 0;
 283         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 284                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 285                         state |= (1 << ptr);
 286         }
 287         drvdata->state = state;
 288
 289         cfg.dev = &pdev->dev;
 290         cfg.init_data = config->init_data;
 291         cfg.driver_data = drvdata;
 292
 293         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 294         if (IS_ERR(drvdata->dev)) {
 295                 ret = PTR_ERR(drvdata->dev);
 296                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 297                 goto err_stategpio;
 298         }
 299
 300         platform_set_drvdata(pdev, drvdata);
 301
 302         return 0;
 303
 304 err_stategpio:
 305         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 306 err_enablegpio:
 307         if (gpio_is_valid(config->enable_gpio))
 308                 gpio_free(config->enable_gpio);
 309 err_memstate:
 310         kfree(drvdata->states);
 311 err_memgpio:
 312         kfree(drvdata->gpios);
 313 err_name:
 314         kfree(drvdata->desc.name);
 315 err:
 316         return ret;
 317 }
 318
 319 static int __devexit gpio_regulator_remove(struct platform_device *pdev)
 320 {
 321         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 322
 323         regulator_unregister(drvdata->dev);
 324
 325         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 326
 327         kfree(drvdata->states);
 328         kfree(drvdata->gpios);
 329
 330         if (gpio_is_valid(drvdata->enable_gpio))
 331                 gpio_free(drvdata->enable_gpio);
 332
 333         kfree(drvdata->desc.name);
 334
 335         return 0;
 336 }
 337
 338 static struct platform_driver gpio_regulator_driver = {
 339         .probe          = gpio_regulator_probe,
 340         .remove         = __devexit_p(gpio_regulator_remove),
 341         .driver         = {
 342                 .name           = "gpio-regulator",
 343                 .owner          = THIS_MODULE,
 344         },
 345 };
 346
 347 static int __init gpio_regulator_init(void)
 348 {
 349         return platform_driver_register(&gpio_regulator_driver);
 350 }
 351 subsys_initcall(gpio_regulator_init);
 352
 353 static void __exit gpio_regulator_exit(void)
 354 {
 355         platform_driver_unregister(&gpio_regulator_driver);
 356 }
 357 module_exit(gpio_regulator_exit);
 358
 359 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 360 MODULE_DESCRIPTION("gpio voltage regulator");
 361 MODULE_LICENSE("GPL");
 362 MODULE_ALIAS("platform:gpio-regulator");