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         if (config->enable_gpio < 0 && config->enable_gpio != -ENOENT)
 166                 return ERR_PTR(config->enable_gpio);
 167
 168         /* Fetch GPIOs. - optional property*/
 169         ret = of_gpio_count(np);
 170         if ((ret < 0) && (ret != -ENOENT))
 171                 return ERR_PTR(ret);
 172
 173         if (ret > 0) {
 174                 config->nr_gpios = ret;
 175                 config->gpios = devm_kzalloc(dev,
 176                                         sizeof(struct gpio) * config->nr_gpios,
 177                                         GFP_KERNEL);
 178                 if (!config->gpios)
 179                         return ERR_PTR(-ENOMEM);
 180
 181                 proplen = of_property_count_u32_elems(np, "gpios-states");
 182                 /* optional property */
 183                 if (proplen < 0)
 184                         proplen = 0;
 185
 186                 if (proplen > 0 && proplen != config->nr_gpios) {
 187                         dev_warn(dev, "gpios <-> gpios-states mismatch\n");
 188                         proplen = 0;
 189                 }
 190
 191                 for (i = 0; i < config->nr_gpios; i++) {
 192                         gpio = of_get_named_gpio(np, "gpios", i);
 193                         if (gpio < 0) {
 194                                 if (gpio != -ENOENT)
 195                                         return ERR_PTR(gpio);
 196                                 break;
 197                         }
 198                         config->gpios[i].gpio = gpio;
 199                         if (proplen > 0) {
 200                                 of_property_read_u32_index(np, "gpios-states",
 201                                                            i, &ret);
 202                                 if (ret)
 203                                         config->gpios[i].flags =
 204                                                            GPIOF_OUT_INIT_HIGH;
 205                         }
 206                 }
 207         }
 208
 209         /* Fetch states. */
 210         proplen = of_property_count_u32_elems(np, "states");
 211         if (proplen < 0) {
 212                 dev_err(dev, "No 'states' property found\n");
 213                 return ERR_PTR(-EINVAL);
 214         }
 215
 216         config->states = devm_kzalloc(dev,
 217                                 sizeof(struct gpio_regulator_state)
 218                                 * (proplen / 2),
 219                                 GFP_KERNEL);
 220         if (!config->states)
 221                 return ERR_PTR(-ENOMEM);
 222
 223         for (i = 0; i < proplen / 2; i++) {
 224                 of_property_read_u32_index(np, "states", i * 2,
 225                                            &config->states[i].value);
 226                 of_property_read_u32_index(np, "states", i * 2 + 1,
 227                                            &config->states[i].gpios);
 228         }
 229         config->nr_states = i;
 230
 231         config->type = REGULATOR_VOLTAGE;
 232         ret = of_property_read_string(np, "regulator-type", &regtype);
 233         if (ret >= 0) {
 234                 if (!strncmp("voltage", regtype, 7))
 235                         config->type = REGULATOR_VOLTAGE;
 236                 else if (!strncmp("current", regtype, 7))
 237                         config->type = REGULATOR_CURRENT;
 238                 else
 239                         dev_warn(dev, "Unknown regulator-type '%s'\n",
 240                                  regtype);
 241         }
 242
 243         return config;
 244 }
 245
 246 static struct regulator_ops gpio_regulator_current_ops = {
 247         .get_current_limit = gpio_regulator_get_value,
 248         .set_current_limit = gpio_regulator_set_current_limit,
 249 };
 250
 251 static int gpio_regulator_probe(struct platform_device *pdev)
 252 {
 253         struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
 254         struct device_node *np = pdev->dev.of_node;
 255         struct gpio_regulator_data *drvdata;
 256         struct regulator_config cfg = { };
 257         int ptr, ret, state;
 258
 259         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
 260                                GFP_KERNEL);
 261         if (drvdata == NULL)
 262                 return -ENOMEM;
 263
 264         if (np) {
 265                 config = of_get_gpio_regulator_config(&pdev->dev, np,
 266                                                       &drvdata->desc);
 267                 if (IS_ERR(config))
 268                         return PTR_ERR(config);
 269         }
 270
 271         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 272         if (drvdata->desc.name == NULL) {
 273                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 274                 return -ENOMEM;
 275         }
 276
 277         if (config->nr_gpios != 0) {
 278                 drvdata->gpios = kmemdup(config->gpios,
 279                                          config->nr_gpios * sizeof(struct gpio),
 280                                          GFP_KERNEL);
 281                 if (drvdata->gpios == NULL) {
 282                         dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 283                         ret = -ENOMEM;
 284                         goto err_name;
 285                 }
 286
 287                 drvdata->nr_gpios = config->nr_gpios;
 288                 ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 289                 if (ret) {
 290                         if (ret != -EPROBE_DEFER)
 291                                 dev_err(&pdev->dev,
 292                                         "Could not obtain regulator setting GPIOs: %d\n",
 293                                         ret);
 294                         goto err_memgpio;
 295                 }
 296         }
 297
 298         drvdata->states = kmemdup(config->states,
 299                                   config->nr_states *
 300                                          sizeof(struct gpio_regulator_state),
 301                                   GFP_KERNEL);
 302         if (drvdata->states == NULL) {
 303                 dev_err(&pdev->dev, "Failed to allocate state data\n");
 304                 ret = -ENOMEM;
 305                 goto err_stategpio;
 306         }
 307         drvdata->nr_states = config->nr_states;
 308
 309         drvdata->desc.owner = THIS_MODULE;
 310         drvdata->desc.enable_time = config->startup_delay;
 311
 312         /* handle regulator type*/
 313         switch (config->type) {
 314         case REGULATOR_VOLTAGE:
 315                 drvdata->desc.type = REGULATOR_VOLTAGE;
 316                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
 317                 drvdata->desc.n_voltages = config->nr_states;
 318                 break;
 319         case REGULATOR_CURRENT:
 320                 drvdata->desc.type = REGULATOR_CURRENT;
 321                 drvdata->desc.ops = &gpio_regulator_current_ops;
 322                 break;
 323         default:
 324                 dev_err(&pdev->dev, "No regulator type set\n");
 325                 ret = -EINVAL;
 326                 goto err_memstate;
 327         }
 328
 329         /* build initial state from gpio init data. */
 330         state = 0;
 331         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 332                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 333                         state |= (1 << ptr);
 334         }
 335         drvdata->state = state;
 336
 337         cfg.dev = &pdev->dev;
 338         cfg.init_data = config->init_data;
 339         cfg.driver_data = drvdata;
 340         cfg.of_node = np;
 341
 342         if (gpio_is_valid(config->enable_gpio)) {
 343                 cfg.ena_gpio = config->enable_gpio;
 344                 cfg.ena_gpio_initialized = true;
 345         }
 346         cfg.ena_gpio_invert = !config->enable_high;
 347         if (config->enabled_at_boot) {
 348                 if (config->enable_high)
 349                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 350                 else
 351                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 352         } else {
 353                 if (config->enable_high)
 354                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 355                 else
 356                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 357         }
 358
 359         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 360         if (IS_ERR(drvdata->dev)) {
 361                 ret = PTR_ERR(drvdata->dev);
 362                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 363                 goto err_memstate;
 364         }
 365
 366         platform_set_drvdata(pdev, drvdata);
 367
 368         return 0;
 369
 370 err_memstate:
 371         kfree(drvdata->states);
 372 err_stategpio:
 373         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 374 err_memgpio:
 375         kfree(drvdata->gpios);
 376 err_name:
 377         kfree(drvdata->desc.name);
 378         return ret;
 379 }
 380
 381 static int gpio_regulator_remove(struct platform_device *pdev)
 382 {
 383         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 384
 385         regulator_unregister(drvdata->dev);
 386
 387         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 388
 389         kfree(drvdata->states);
 390         kfree(drvdata->gpios);
 391
 392         kfree(drvdata->desc.name);
 393
 394         return 0;
 395 }
 396
 397 #if defined(CONFIG_OF)
 398 static const struct of_device_id regulator_gpio_of_match[] = {
 399         { .compatible = "regulator-gpio", },
 400         {},
 401 };
 402 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
 403 #endif
 404
 405 static struct platform_driver gpio_regulator_driver = {
 406         .probe          = gpio_regulator_probe,
 407         .remove         = gpio_regulator_remove,
 408         .driver         = {
 409                 .name           = "gpio-regulator",
 410                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
 411         },
 412 };
 413
 414 static int __init gpio_regulator_init(void)
 415 {
 416         return platform_driver_register(&gpio_regulator_driver);
 417 }
 418 subsys_initcall(gpio_regulator_init);
 419
 420 static void __exit gpio_regulator_exit(void)
 421 {
 422         platform_driver_unregister(&gpio_regulator_driver);
 423 }
 424 module_exit(gpio_regulator_exit);
 425
 426 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 427 MODULE_DESCRIPTION("gpio voltage regulator");
 428 MODULE_LICENSE("GPL");
 429 MODULE_ALIAS("platform:gpio-regulator");