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/delay.h>
  34 #include <linux/slab.h>
  35
  36 struct gpio_regulator_data {
  37         struct regulator_desc desc;
  38         struct regulator_dev *dev;
  39
  40         int enable_gpio;
  41         bool enable_high;
  42         bool is_enabled;
  43         unsigned startup_delay;
  44
  45         struct gpio *gpios;
  46         int nr_gpios;
  47
  48         struct gpio_regulator_state *states;
  49         int nr_states;
  50
  51         int state;
  52 };
  53
  54 static int gpio_regulator_is_enabled(struct regulator_dev *dev)
  55 {
  56         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  57
  58         return data->is_enabled;
  59 }
  60
  61 static int gpio_regulator_enable(struct regulator_dev *dev)
  62 {
  63         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  64
  65         if (gpio_is_valid(data->enable_gpio)) {
  66                 gpio_set_value_cansleep(data->enable_gpio, data->enable_high);
  67                 data->is_enabled = true;
  68         }
  69
  70         return 0;
  71 }
  72
  73 static int gpio_regulator_disable(struct regulator_dev *dev)
  74 {
  75         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  76
  77         if (gpio_is_valid(data->enable_gpio)) {
  78                 gpio_set_value_cansleep(data->enable_gpio, !data->enable_high);
  79                 data->is_enabled = false;
  80         }
  81
  82         return 0;
  83 }
  84
  85 static int gpio_regulator_enable_time(struct regulator_dev *dev)
  86 {
  87         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  88
  89         return data->startup_delay;
  90 }
  91
  92 static int gpio_regulator_get_value(struct regulator_dev *dev)
  93 {
  94         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  95         int ptr;
  96
  97         for (ptr = 0; ptr < data->nr_states; ptr++)
  98                 if (data->states[ptr].gpios == data->state)
  99                         return data->states[ptr].value;
 100
 101         return -EINVAL;
 102 }
 103
 104 static int gpio_regulator_set_value(struct regulator_dev *dev,
 105                                         int min, int max)
 106 {
 107         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 108         int ptr, target, state;
 109
 110         target = -1;
 111         for (ptr = 0; ptr < data->nr_states; ptr++)
 112                 if (data->states[ptr].value >= min &&
 113                     data->states[ptr].value <= max)
 114                         target = data->states[ptr].gpios;
 115
 116         if (target < 0)
 117                 return -EINVAL;
 118
 119         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 120                 state = (target & (1 << ptr)) >> ptr;
 121                 gpio_set_value(data->gpios[ptr].gpio, state);
 122         }
 123         data->state = target;
 124
 125         return 0;
 126 }
 127
 128 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
 129                                         int min_uV, int max_uV,
 130                                         unsigned *selector)
 131 {
 132         return gpio_regulator_set_value(dev, min_uV, max_uV);
 133 }
 134
 135 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
 136                                       unsigned selector)
 137 {
 138         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 139
 140         if (selector >= data->nr_states)
 141                 return -EINVAL;
 142
 143         return data->states[selector].value;
 144 }
 145
 146 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
 147                                         int min_uA, int max_uA)
 148 {
 149         return gpio_regulator_set_value(dev, min_uA, max_uA);
 150 }
 151
 152 static struct regulator_ops gpio_regulator_voltage_ops = {
 153         .is_enabled = gpio_regulator_is_enabled,
 154         .enable = gpio_regulator_enable,
 155         .disable = gpio_regulator_disable,
 156         .enable_time = gpio_regulator_enable_time,
 157         .get_voltage = gpio_regulator_get_value,
 158         .set_voltage = gpio_regulator_set_voltage,
 159         .list_voltage = gpio_regulator_list_voltage,
 160 };
 161
 162 static struct regulator_ops gpio_regulator_current_ops = {
 163         .is_enabled = gpio_regulator_is_enabled,
 164         .enable = gpio_regulator_enable,
 165         .disable = gpio_regulator_disable,
 166         .enable_time = gpio_regulator_enable_time,
 167         .get_current_limit = gpio_regulator_get_value,
 168         .set_current_limit = gpio_regulator_set_current_limit,
 169 };
 170
 171 static int __devinit gpio_regulator_probe(struct platform_device *pdev)
 172 {
 173         struct gpio_regulator_config *config = pdev->dev.platform_data;
 174         struct gpio_regulator_data *drvdata;
 175         int ptr, ret, state;
 176
 177         drvdata = kzalloc(sizeof(struct gpio_regulator_data), GFP_KERNEL);
 178         if (drvdata == NULL) {
 179                 dev_err(&pdev->dev, "Failed to allocate device data\n");
 180                 return -ENOMEM;
 181         }
 182
 183         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 184         if (drvdata->desc.name == NULL) {
 185                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 186                 ret = -ENOMEM;
 187                 goto err;
 188         }
 189
 190         drvdata->gpios = kmemdup(config->gpios,
 191                                  config->nr_gpios * sizeof(struct gpio),
 192                                  GFP_KERNEL);
 193         if (drvdata->gpios == NULL) {
 194                 dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 195                 ret = -ENOMEM;
 196                 goto err_name;
 197         }
 198
 199         drvdata->states = kmemdup(config->states,
 200                                   config->nr_states *
 201                                          sizeof(struct gpio_regulator_state),
 202                                   GFP_KERNEL);
 203         if (drvdata->states == NULL) {
 204                 dev_err(&pdev->dev, "Failed to allocate state data\n");
 205                 ret = -ENOMEM;
 206                 goto err_memgpio;
 207         }
 208         drvdata->nr_states = config->nr_states;
 209
 210         drvdata->desc.owner = THIS_MODULE;
 211
 212         /* handle regulator type*/
 213         switch (config->type) {
 214         case REGULATOR_VOLTAGE:
 215                 drvdata->desc.type = REGULATOR_VOLTAGE;
 216                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
 217                 drvdata->desc.n_voltages = config->nr_states;
 218                 break;
 219         case REGULATOR_CURRENT:
 220                 drvdata->desc.type = REGULATOR_CURRENT;
 221                 drvdata->desc.ops = &gpio_regulator_current_ops;
 222                 break;
 223         default:
 224                 dev_err(&pdev->dev, "No regulator type set\n");
 225                 ret = -EINVAL;
 226                 goto err_memgpio;
 227                 break;
 228         }
 229
 230         drvdata->enable_gpio = config->enable_gpio;
 231         drvdata->startup_delay = config->startup_delay;
 232
 233         if (gpio_is_valid(config->enable_gpio)) {
 234                 drvdata->enable_high = config->enable_high;
 235
 236                 ret = gpio_request(config->enable_gpio, config->supply_name);
 237                 if (ret) {
 238                         dev_err(&pdev->dev,
 239                            "Could not obtain regulator enable GPIO %d: %d\n",
 240                                                 config->enable_gpio, ret);
 241                         goto err_memstate;
 242                 }
 243
 244                 /* set output direction without changing state
 245                  * to prevent glitch
 246                  */
 247                 if (config->enabled_at_boot) {
 248                         drvdata->is_enabled = true;
 249                         ret = gpio_direction_output(config->enable_gpio,
 250                                                     config->enable_high);
 251                 } else {
 252                         drvdata->is_enabled = false;
 253                         ret = gpio_direction_output(config->enable_gpio,
 254                                                     !config->enable_high);
 255                 }
 256
 257                 if (ret) {
 258                         dev_err(&pdev->dev,
 259                            "Could not configure regulator enable GPIO %d direction: %d\n",
 260                                                 config->enable_gpio, ret);
 261                         goto err_enablegpio;
 262                 }
 263         } else {
 264                 /* Regulator without GPIO control is considered
 265                  * always enabled
 266                  */
 267                 drvdata->is_enabled = true;
 268         }
 269
 270         drvdata->nr_gpios = config->nr_gpios;
 271         ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 272         if (ret) {
 273                 dev_err(&pdev->dev,
 274                    "Could not obtain regulator setting GPIOs: %d\n", ret);
 275                 goto err_enablegpio;
 276         }
 277
 278         /* build initial state from gpio init data. */
 279         state = 0;
 280         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 281                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 282                         state |= (1 << ptr);
 283         }
 284         drvdata->state = state;
 285
 286         drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
 287                                           config->init_data, drvdata);
 288         if (IS_ERR(drvdata->dev)) {
 289                 ret = PTR_ERR(drvdata->dev);
 290                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 291                 goto err_stategpio;
 292         }
 293
 294         platform_set_drvdata(pdev, drvdata);
 295
 296         return 0;
 297
 298 err_stategpio:
 299         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 300 err_enablegpio:
 301         if (gpio_is_valid(config->enable_gpio))
 302                 gpio_free(config->enable_gpio);
 303 err_memstate:
 304         kfree(drvdata->states);
 305 err_memgpio:
 306         kfree(drvdata->gpios);
 307 err_name:
 308         kfree(drvdata->desc.name);
 309 err:
 310         kfree(drvdata);
 311         return ret;
 312 }
 313
 314 static int __devexit gpio_regulator_remove(struct platform_device *pdev)
 315 {
 316         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 317
 318         regulator_unregister(drvdata->dev);
 319
 320         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 321
 322         kfree(drvdata->states);
 323         kfree(drvdata->gpios);
 324
 325         if (gpio_is_valid(drvdata->enable_gpio))
 326                 gpio_free(drvdata->enable_gpio);
 327
 328         kfree(drvdata->desc.name);
 329         kfree(drvdata);
 330
 331         return 0;
 332 }
 333
 334 static struct platform_driver gpio_regulator_driver = {
 335         .probe          = gpio_regulator_probe,
 336         .remove         = __devexit_p(gpio_regulator_remove),
 337         .driver         = {
 338                 .name           = "gpio-regulator",
 339                 .owner          = THIS_MODULE,
 340         },
 341 };
 342
 343 static int __init gpio_regulator_init(void)
 344 {
 345         return platform_driver_register(&gpio_regulator_driver);
 346 }
 347 subsys_initcall(gpio_regulator_init);
 348
 349 static void __exit gpio_regulator_exit(void)
 350 {
 351         platform_driver_unregister(&gpio_regulator_driver);
 352 }
 353 module_exit(gpio_regulator_exit);
 354
 355 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 356 MODULE_DESCRIPTION("gpio voltage regulator");
 357 MODULE_LICENSE("GPL");
 358 MODULE_ALIAS("platform:gpio-regulator");