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/of_regulator.h>
  32 #include <linux/regulator/gpio-regulator.h>
  33 #include <linux/gpio.h>
  34 #include <linux/slab.h>
  35 #include <linux/of.h>
  36 #include <linux/of_gpio.h>
  37
  38 struct gpio_regulator_data {
  39         struct regulator_desc desc;
  40         struct regulator_dev *dev;
  41
  42         struct gpio *gpios;
  43         int nr_gpios;
  44
  45         struct gpio_regulator_state *states;
  46         int nr_states;
  47
  48         int state;
  49 };
  50
  51 static int gpio_regulator_get_value(struct regulator_dev *dev)
  52 {
  53         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  54         int ptr;
  55
  56         for (ptr = 0; ptr < data->nr_states; ptr++)
  57                 if (data->states[ptr].gpios == data->state)
  58                         return data->states[ptr].value;
  59
  60         return -EINVAL;
  61 }
  62
  63 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
  64                                         int min_uV, int max_uV,
  65                                         unsigned *selector)
  66 {
  67         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  68         int ptr, target = 0, state, best_val = INT_MAX;
  69
  70         for (ptr = 0; ptr < data->nr_states; ptr++)
  71                 if (data->states[ptr].value < best_val &&
  72                     data->states[ptr].value >= min_uV &&
  73                     data->states[ptr].value <= max_uV) {
  74                         target = data->states[ptr].gpios;
  75                         best_val = data->states[ptr].value;
  76                         if (selector)
  77                                 *selector = ptr;
  78                 }
  79
  80         if (best_val == INT_MAX)
  81                 return -EINVAL;
  82
  83         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
  84                 state = (target & (1 << ptr)) >> ptr;
  85                 gpio_set_value_cansleep(data->gpios[ptr].gpio, state);
  86         }
  87         data->state = target;
  88
  89         return 0;
  90 }
  91
  92 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
  93                                       unsigned selector)
  94 {
  95         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  96
  97         if (selector >= data->nr_states)
  98                 return -EINVAL;
  99
 100         return data->states[selector].value;
 101 }
 102
 103 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
 104                                         int min_uA, int max_uA)
 105 {
 106         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 107         int ptr, target = 0, state, best_val = 0;
 108
 109         for (ptr = 0; ptr < data->nr_states; ptr++)
 110                 if (data->states[ptr].value > best_val &&
 111                     data->states[ptr].value >= min_uA &&
 112                     data->states[ptr].value <= max_uA) {
 113                         target = data->states[ptr].gpios;
 114                         best_val = data->states[ptr].value;
 115                 }
 116
 117         if (best_val == 0)
 118                 return -EINVAL;
 119
 120         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 121                 state = (target & (1 << ptr)) >> ptr;
 122                 gpio_set_value_cansleep(data->gpios[ptr].gpio, state);
 123         }
 124         data->state = target;
 125
 126         return 0;
 127 }
 128
 129 static struct regulator_ops gpio_regulator_voltage_ops = {
 130         .get_voltage = gpio_regulator_get_value,
 131         .set_voltage = gpio_regulator_set_voltage,
 132         .list_voltage = gpio_regulator_list_voltage,
 133 };
 134
 135 static struct gpio_regulator_config *
 136 of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
 137                              const struct regulator_desc *desc)
 138 {
 139         struct gpio_regulator_config *config;
 140         const char *regtype;
 141         int proplen, gpio, i;
 142         int ret;
 143
 144         config = devm_kzalloc(dev,
 145                         sizeof(struct gpio_regulator_config),
 146                         GFP_KERNEL);
 147         if (!config)
 148                 return ERR_PTR(-ENOMEM);
 149
 150         config->init_data = of_get_regulator_init_data(dev, np, desc);
 151         if (!config->init_data)
 152                 return ERR_PTR(-EINVAL);
 153
 154         config->supply_name = config->init_data->constraints.name;
 155
 156         if (of_property_read_bool(np, "enable-active-high"))
 157                 config->enable_high = true;
 158
 159         if (of_property_read_bool(np, "enable-at-boot"))
 160                 config->enabled_at_boot = true;
 161
 162         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 163
 164         config->enable_gpio = of_get_named_gpio(np, "enable-gpio", 0);
 165
 166         /* Fetch GPIOs. - optional property*/
 167         ret = of_gpio_count(np);
 168         if ((ret < 0) && (ret != -ENOENT))
 169                 return ERR_PTR(ret);
 170
 171         if (ret > 0) {
 172                 config->nr_gpios = ret;
 173                 config->gpios = devm_kzalloc(dev,
 174                                         sizeof(struct gpio) * config->nr_gpios,
 175                                         GFP_KERNEL);
 176                 if (!config->gpios)
 177                         return ERR_PTR(-ENOMEM);
 178
 179                 proplen = of_property_count_u32_elems(np, "gpios-states");
 180                 /* optional property */
 181                 if (proplen < 0)
 182                         proplen = 0;
 183
 184                 if (proplen > 0 && proplen != config->nr_gpios) {
 185                         dev_warn(dev, "gpios <-> gpios-states mismatch\n");
 186                         proplen = 0;
 187                 }
 188
 189                 for (i = 0; i < config->nr_gpios; i++) {
 190                         gpio = of_get_named_gpio(np, "gpios", i);
 191                         if (gpio < 0)
 192                                 break;
 193                         config->gpios[i].gpio = gpio;
 194                         if (proplen > 0) {
 195                                 of_property_read_u32_index(np, "gpios-states",
 196                                                            i, &ret);
 197                                 if (ret)
 198                                         config->gpios[i].flags =
 199                                                            GPIOF_OUT_INIT_HIGH;
 200                         }
 201                 }
 202         }
 203
 204         /* Fetch states. */
 205         proplen = of_property_count_u32_elems(np, "states");
 206         if (proplen < 0) {
 207                 dev_err(dev, "No 'states' property found\n");
 208                 return ERR_PTR(-EINVAL);
 209         }
 210
 211         config->states = devm_kzalloc(dev,
 212                                 sizeof(struct gpio_regulator_state)
 213                                 * (proplen / 2),
 214                                 GFP_KERNEL);
 215         if (!config->states)
 216                 return ERR_PTR(-ENOMEM);
 217
 218         for (i = 0; i < proplen / 2; i++) {
 219                 of_property_read_u32_index(np, "states", i * 2,
 220                                            &config->states[i].value);
 221                 of_property_read_u32_index(np, "states", i * 2 + 1,
 222                                            &config->states[i].gpios);
 223         }
 224         config->nr_states = i;
 225
 226         config->type = REGULATOR_VOLTAGE;
 227         ret = of_property_read_string(np, "regulator-type", &regtype);
 228         if (ret >= 0) {
 229                 if (!strncmp("voltage", regtype, 7))
 230                         config->type = REGULATOR_VOLTAGE;
 231                 else if (!strncmp("current", regtype, 7))
 232                         config->type = REGULATOR_CURRENT;
 233                 else
 234                         dev_warn(dev, "Unknown regulator-type '%s'\n",
 235                                  regtype);
 236         }
 237
 238         return config;
 239 }
 240
 241 static struct regulator_ops gpio_regulator_current_ops = {
 242         .get_current_limit = gpio_regulator_get_value,
 243         .set_current_limit = gpio_regulator_set_current_limit,
 244 };
 245
 246 static int gpio_regulator_probe(struct platform_device *pdev)
 247 {
 248         struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
 249         struct device_node *np = pdev->dev.of_node;
 250         struct gpio_regulator_data *drvdata;
 251         struct regulator_config cfg = { };
 252         int ptr, ret, state;
 253
 254         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
 255                                GFP_KERNEL);
 256         if (drvdata == NULL)
 257                 return -ENOMEM;
 258
 259         if (np) {
 260                 config = of_get_gpio_regulator_config(&pdev->dev, np,
 261                                                       &drvdata->desc);
 262                 if (IS_ERR(config))
 263                         return PTR_ERR(config);
 264         }
 265
 266         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 267         if (drvdata->desc.name == NULL) {
 268                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 269                 ret = -ENOMEM;
 270                 goto err;
 271         }
 272
 273         if (config->nr_gpios != 0) {
 274                 drvdata->gpios = kmemdup(config->gpios,
 275                                          config->nr_gpios * sizeof(struct gpio),
 276                                          GFP_KERNEL);
 277                 if (drvdata->gpios == NULL) {
 278                         dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 279                         ret = -ENOMEM;
 280                         goto err_name;
 281                 }
 282
 283                 drvdata->nr_gpios = config->nr_gpios;
 284                 ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 285                 if (ret) {
 286                         dev_err(&pdev->dev,
 287                         "Could not obtain regulator setting GPIOs: %d\n", ret);
 288                         goto err_memstate;
 289                 }
 290         }
 291
 292         drvdata->states = kmemdup(config->states,
 293                                   config->nr_states *
 294                                          sizeof(struct gpio_regulator_state),
 295                                   GFP_KERNEL);
 296         if (drvdata->states == NULL) {
 297                 dev_err(&pdev->dev, "Failed to allocate state data\n");
 298                 ret = -ENOMEM;
 299                 goto err_memgpio;
 300         }
 301         drvdata->nr_states = config->nr_states;
 302
 303         drvdata->desc.owner = THIS_MODULE;
 304         drvdata->desc.enable_time = config->startup_delay;
 305
 306         /* handle regulator type*/
 307         switch (config->type) {
 308         case REGULATOR_VOLTAGE:
 309                 drvdata->desc.type = REGULATOR_VOLTAGE;
 310                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
 311                 drvdata->desc.n_voltages = config->nr_states;
 312                 break;
 313         case REGULATOR_CURRENT:
 314                 drvdata->desc.type = REGULATOR_CURRENT;
 315                 drvdata->desc.ops = &gpio_regulator_current_ops;
 316                 break;
 317         default:
 318                 dev_err(&pdev->dev, "No regulator type set\n");
 319                 ret = -EINVAL;
 320                 goto err_memgpio;
 321         }
 322
 323         /* build initial state from gpio init data. */
 324         state = 0;
 325         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 326                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 327                         state |= (1 << ptr);
 328         }
 329         drvdata->state = state;
 330
 331         cfg.dev = &pdev->dev;
 332         cfg.init_data = config->init_data;
 333         cfg.driver_data = drvdata;
 334         cfg.of_node = np;
 335
 336         if (gpio_is_valid(config->enable_gpio)) {
 337                 cfg.ena_gpio = config->enable_gpio;
 338                 cfg.ena_gpio_initialized = true;
 339         }
 340         cfg.ena_gpio_invert = !config->enable_high;
 341         if (config->enabled_at_boot) {
 342                 if (config->enable_high)
 343                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 344                 else
 345                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 346         } else {
 347                 if (config->enable_high)
 348                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 349                 else
 350                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 351         }
 352
 353         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 354         if (IS_ERR(drvdata->dev)) {
 355                 ret = PTR_ERR(drvdata->dev);
 356                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 357                 goto err_stategpio;
 358         }
 359
 360         platform_set_drvdata(pdev, drvdata);
 361
 362         return 0;
 363
 364 err_stategpio:
 365         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 366 err_memstate:
 367         kfree(drvdata->states);
 368 err_memgpio:
 369         kfree(drvdata->gpios);
 370 err_name:
 371         kfree(drvdata->desc.name);
 372 err:
 373         return ret;
 374 }
 375
 376 static int gpio_regulator_remove(struct platform_device *pdev)
 377 {
 378         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 379
 380         regulator_unregister(drvdata->dev);
 381
 382         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 383
 384         kfree(drvdata->states);
 385         kfree(drvdata->gpios);
 386
 387         kfree(drvdata->desc.name);
 388
 389         return 0;
 390 }
 391
 392 #if defined(CONFIG_OF)
 393 static const struct of_device_id regulator_gpio_of_match[] = {
 394         { .compatible = "regulator-gpio", },
 395         {},
 396 };
 397 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
 398 #endif
 399
 400 static struct platform_driver gpio_regulator_driver = {
 401         .probe          = gpio_regulator_probe,
 402         .remove         = gpio_regulator_remove,
 403         .driver         = {
 404                 .name           = "gpio-regulator",
 405                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
 406         },
 407 };
 408
 409 static int __init gpio_regulator_init(void)
 410 {
 411         return platform_driver_register(&gpio_regulator_driver);
 412 }
 413 subsys_initcall(gpio_regulator_init);
 414
 415 static void __exit gpio_regulator_exit(void)
 416 {
 417         platform_driver_unregister(&gpio_regulator_driver);
 418 }
 419 module_exit(gpio_regulator_exit);
 420
 421 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 422 MODULE_DESCRIPTION("gpio voltage regulator");
 423 MODULE_LICENSE("GPL");
 424 MODULE_ALIAS("platform:gpio-regulator");