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/gpio/consumer.h>
  35 #include <linux/slab.h>
  36 #include <linux/of.h>
  37 #include <linux/of_gpio.h>
  38
  39 struct gpio_regulator_data {
  40         struct regulator_desc desc;
  41         struct regulator_dev *dev;
  42
  43         struct gpio *gpios;
  44         int nr_gpios;
  45
  46         struct gpio_regulator_state *states;
  47         int nr_states;
  48
  49         int state;
  50 };
  51
  52 static int gpio_regulator_get_value(struct regulator_dev *dev)
  53 {
  54         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  55         int ptr;
  56
  57         for (ptr = 0; ptr < data->nr_states; ptr++)
  58                 if (data->states[ptr].gpios == data->state)
  59                         return data->states[ptr].value;
  60
  61         return -EINVAL;
  62 }
  63
  64 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
  65                                         int min_uV, int max_uV,
  66                                         unsigned *selector)
  67 {
  68         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  69         int ptr, target = 0, state, best_val = INT_MAX;
  70
  71         for (ptr = 0; ptr < data->nr_states; ptr++)
  72                 if (data->states[ptr].value < best_val &&
  73                     data->states[ptr].value >= min_uV &&
  74                     data->states[ptr].value <= max_uV) {
  75                         target = data->states[ptr].gpios;
  76                         best_val = data->states[ptr].value;
  77                         if (selector)
  78                                 *selector = ptr;
  79                 }
  80
  81         if (best_val == INT_MAX)
  82                 return -EINVAL;
  83
  84         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
  85                 state = (target & (1 << ptr)) >> ptr;
  86                 gpio_set_value_cansleep(data->gpios[ptr].gpio, state);
  87         }
  88         data->state = target;
  89
  90         return 0;
  91 }
  92
  93 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
  94                                       unsigned selector)
  95 {
  96         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  97
  98         if (selector >= data->nr_states)
  99                 return -EINVAL;
 100
 101         return data->states[selector].value;
 102 }
 103
 104 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
 105                                         int min_uA, int max_uA)
 106 {
 107         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 108         int ptr, target = 0, state, best_val = 0;
 109
 110         for (ptr = 0; ptr < data->nr_states; ptr++)
 111                 if (data->states[ptr].value > best_val &&
 112                     data->states[ptr].value >= min_uA &&
 113                     data->states[ptr].value <= max_uA) {
 114                         target = data->states[ptr].gpios;
 115                         best_val = data->states[ptr].value;
 116                 }
 117
 118         if (best_val == 0)
 119                 return -EINVAL;
 120
 121         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 122                 state = (target & (1 << ptr)) >> ptr;
 123                 gpio_set_value_cansleep(data->gpios[ptr].gpio, state);
 124         }
 125         data->state = target;
 126
 127         return 0;
 128 }
 129
 130 static struct regulator_ops gpio_regulator_voltage_ops = {
 131         .get_voltage = gpio_regulator_get_value,
 132         .set_voltage = gpio_regulator_set_voltage,
 133         .list_voltage = gpio_regulator_list_voltage,
 134 };
 135
 136 static struct gpio_regulator_config *
 137 of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
 138                              const struct regulator_desc *desc)
 139 {
 140         struct gpio_regulator_config *config;
 141         const char *regtype;
 142         int proplen, gpio, i;
 143         int ret;
 144
 145         config = devm_kzalloc(dev,
 146                         sizeof(struct gpio_regulator_config),
 147                         GFP_KERNEL);
 148         if (!config)
 149                 return ERR_PTR(-ENOMEM);
 150
 151         config->init_data = of_get_regulator_init_data(dev, np, desc);
 152         if (!config->init_data)
 153                 return ERR_PTR(-EINVAL);
 154
 155         config->supply_name = config->init_data->constraints.name;
 156
 157         if (of_property_read_bool(np, "enable-active-high"))
 158                 config->enable_high = true;
 159
 160         if (of_property_read_bool(np, "enable-at-boot"))
 161                 config->enabled_at_boot = true;
 162
 163         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 164
 165         /* Fetch GPIOs. - optional property*/
 166         ret = of_gpio_count(np);
 167         if ((ret < 0) && (ret != -ENOENT))
 168                 return ERR_PTR(ret);
 169
 170         if (ret > 0) {
 171                 config->nr_gpios = ret;
 172                 config->gpios = devm_kzalloc(dev,
 173                                         sizeof(struct gpio) * config->nr_gpios,
 174                                         GFP_KERNEL);
 175                 if (!config->gpios)
 176                         return ERR_PTR(-ENOMEM);
 177
 178                 proplen = of_property_count_u32_elems(np, "gpios-states");
 179                 /* optional property */
 180                 if (proplen < 0)
 181                         proplen = 0;
 182
 183                 if (proplen > 0 && proplen != config->nr_gpios) {
 184                         dev_warn(dev, "gpios <-> gpios-states mismatch\n");
 185                         proplen = 0;
 186                 }
 187
 188                 for (i = 0; i < config->nr_gpios; i++) {
 189                         gpio = of_get_named_gpio(np, "gpios", i);
 190                         if (gpio < 0) {
 191                                 if (gpio != -ENOENT)
 192                                         return ERR_PTR(gpio);
 193                                 break;
 194                         }
 195                         config->gpios[i].gpio = gpio;
 196                         config->gpios[i].label = config->supply_name;
 197                         if (proplen > 0) {
 198                                 of_property_read_u32_index(np, "gpios-states",
 199                                                            i, &ret);
 200                                 if (ret)
 201                                         config->gpios[i].flags =
 202                                                            GPIOF_OUT_INIT_HIGH;
 203                         }
 204                 }
 205         }
 206
 207         /* Fetch states. */
 208         proplen = of_property_count_u32_elems(np, "states");
 209         if (proplen < 0) {
 210                 dev_err(dev, "No 'states' property found\n");
 211                 return ERR_PTR(-EINVAL);
 212         }
 213
 214         config->states = devm_kzalloc(dev,
 215                                 sizeof(struct gpio_regulator_state)
 216                                 * (proplen / 2),
 217                                 GFP_KERNEL);
 218         if (!config->states)
 219                 return ERR_PTR(-ENOMEM);
 220
 221         for (i = 0; i < proplen / 2; i++) {
 222                 of_property_read_u32_index(np, "states", i * 2,
 223                                            &config->states[i].value);
 224                 of_property_read_u32_index(np, "states", i * 2 + 1,
 225                                            &config->states[i].gpios);
 226         }
 227         config->nr_states = i;
 228
 229         config->type = REGULATOR_VOLTAGE;
 230         ret = of_property_read_string(np, "regulator-type", &regtype);
 231         if (ret >= 0) {
 232                 if (!strncmp("voltage", regtype, 7))
 233                         config->type = REGULATOR_VOLTAGE;
 234                 else if (!strncmp("current", regtype, 7))
 235                         config->type = REGULATOR_CURRENT;
 236                 else
 237                         dev_warn(dev, "Unknown regulator-type '%s'\n",
 238                                  regtype);
 239         }
 240
 241         return config;
 242 }
 243
 244 static struct regulator_ops gpio_regulator_current_ops = {
 245         .get_current_limit = gpio_regulator_get_value,
 246         .set_current_limit = gpio_regulator_set_current_limit,
 247 };
 248
 249 static int gpio_regulator_probe(struct platform_device *pdev)
 250 {
 251         struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
 252         struct device_node *np = pdev->dev.of_node;
 253         struct gpio_regulator_data *drvdata;
 254         struct regulator_config cfg = { };
 255         enum gpiod_flags gflags;
 256         int ptr, ret, state;
 257
 258         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
 259                                GFP_KERNEL);
 260         if (drvdata == NULL)
 261                 return -ENOMEM;
 262
 263         if (np) {
 264                 config = of_get_gpio_regulator_config(&pdev->dev, np,
 265                                                       &drvdata->desc);
 266                 if (IS_ERR(config))
 267                         return PTR_ERR(config);
 268         }
 269
 270         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 271         if (drvdata->desc.name == NULL) {
 272                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 273                 return -ENOMEM;
 274         }
 275
 276         if (config->nr_gpios != 0) {
 277                 drvdata->gpios = kmemdup(config->gpios,
 278                                          config->nr_gpios * sizeof(struct gpio),
 279                                          GFP_KERNEL);
 280                 if (drvdata->gpios == NULL) {
 281                         dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 282                         ret = -ENOMEM;
 283                         goto err_name;
 284                 }
 285
 286                 drvdata->nr_gpios = config->nr_gpios;
 287                 ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 288                 if (ret) {
 289                         if (ret != -EPROBE_DEFER)
 290                                 dev_err(&pdev->dev,
 291                                         "Could not obtain regulator setting GPIOs: %d\n",
 292                                         ret);
 293                         goto err_memgpio;
 294                 }
 295         }
 296
 297         drvdata->states = kmemdup(config->states,
 298                                   config->nr_states *
 299                                          sizeof(struct gpio_regulator_state),
 300                                   GFP_KERNEL);
 301         if (drvdata->states == NULL) {
 302                 dev_err(&pdev->dev, "Failed to allocate state data\n");
 303                 ret = -ENOMEM;
 304                 goto err_stategpio;
 305         }
 306         drvdata->nr_states = config->nr_states;
 307
 308         drvdata->desc.owner = THIS_MODULE;
 309         drvdata->desc.enable_time = config->startup_delay;
 310
 311         /* handle regulator type*/
 312         switch (config->type) {
 313         case REGULATOR_VOLTAGE:
 314                 drvdata->desc.type = REGULATOR_VOLTAGE;
 315                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
 316                 drvdata->desc.n_voltages = config->nr_states;
 317                 break;
 318         case REGULATOR_CURRENT:
 319                 drvdata->desc.type = REGULATOR_CURRENT;
 320                 drvdata->desc.ops = &gpio_regulator_current_ops;
 321                 break;
 322         default:
 323                 dev_err(&pdev->dev, "No regulator type set\n");
 324                 ret = -EINVAL;
 325                 goto err_memstate;
 326         }
 327
 328         /* build initial state from gpio init data. */
 329         state = 0;
 330         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 331                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 332                         state |= (1 << ptr);
 333         }
 334         drvdata->state = state;
 335
 336         cfg.dev = &pdev->dev;
 337         cfg.init_data = config->init_data;
 338         cfg.driver_data = drvdata;
 339         cfg.of_node = np;
 340
 341         cfg.ena_gpio_invert = !config->enable_high;
 342         if (config->enabled_at_boot) {
 343                 if (config->enable_high)
 344                         gflags = GPIOD_OUT_HIGH;
 345                 else
 346                         gflags = GPIOD_OUT_LOW;
 347         } else {
 348                 if (config->enable_high)
 349                         gflags = GPIOD_OUT_LOW;
 350                 else
 351                         gflags = GPIOD_OUT_HIGH;
 352         }
 353         cfg.ena_gpiod = devm_gpiod_get_optional(&pdev->dev, "enable", gflags);
 354         if (IS_ERR(cfg.ena_gpiod)) {
 355                 ret = PTR_ERR(cfg.ena_gpiod);
 356                 goto err_stategpio;
 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");