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 {
 138         struct gpio_regulator_config *config;
 139         const char *regtype;
 140         int proplen, gpio, i;
 141         int ret;
 142
 143         config = devm_kzalloc(dev,
 144                         sizeof(struct gpio_regulator_config),
 145                         GFP_KERNEL);
 146         if (!config)
 147                 return ERR_PTR(-ENOMEM);
 148
 149         config->init_data = of_get_regulator_init_data(dev, np);
 150         if (!config->init_data)
 151                 return ERR_PTR(-EINVAL);
 152
 153         config->supply_name = config->init_data->constraints.name;
 154
 155         if (of_property_read_bool(np, "enable-active-high"))
 156                 config->enable_high = true;
 157
 158         if (of_property_read_bool(np, "enable-at-boot"))
 159                 config->enabled_at_boot = true;
 160
 161         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 162
 163         config->enable_gpio = of_get_named_gpio(np, "enable-gpio", 0);
 164
 165         /* Fetch GPIOs. */
 166         config->nr_gpios = of_gpio_count(np);
 167
 168         config->gpios = devm_kzalloc(dev,
 169                                 sizeof(struct gpio) * config->nr_gpios,
 170                                 GFP_KERNEL);
 171         if (!config->gpios)
 172                 return ERR_PTR(-ENOMEM);
 173
 174         proplen = of_property_count_u32_elems(np, "gpios-states");
 175         /* optional property */
 176         if (proplen < 0)
 177                 proplen = 0;
 178
 179         if (proplen > 0 && proplen != config->nr_gpios) {
 180                 dev_warn(dev, "gpios <-> gpios-states mismatch\n");
 181                 proplen = 0;
 182         }
 183
 184         for (i = 0; i < config->nr_gpios; i++) {
 185                 gpio = of_get_named_gpio(np, "gpios", i);
 186                 if (gpio < 0)
 187                         break;
 188                 config->gpios[i].gpio = gpio;
 189                 if (proplen > 0) {
 190                         of_property_read_u32_index(np, "gpios-states", i, &ret);
 191                         if (ret)
 192                                 config->gpios[i].flags = GPIOF_OUT_INIT_HIGH;
 193                 }
 194         }
 195
 196         /* Fetch states. */
 197         proplen = of_property_count_u32_elems(np, "states");
 198         if (proplen < 0) {
 199                 dev_err(dev, "No 'states' property found\n");
 200                 return ERR_PTR(-EINVAL);
 201         }
 202
 203         config->states = devm_kzalloc(dev,
 204                                 sizeof(struct gpio_regulator_state)
 205                                 * (proplen / 2),
 206                                 GFP_KERNEL);
 207         if (!config->states)
 208                 return ERR_PTR(-ENOMEM);
 209
 210         for (i = 0; i < proplen / 2; i++) {
 211                 of_property_read_u32_index(np, "states", i * 2,
 212                                            &config->states[i].value);
 213                 of_property_read_u32_index(np, "states", i * 2 + 1,
 214                                            &config->states[i].gpios);
 215         }
 216         config->nr_states = i;
 217
 218         config->type = REGULATOR_VOLTAGE;
 219         ret = of_property_read_string(np, "regulator-type", &regtype);
 220         if (ret >= 0) {
 221                 if (!strncmp("voltage", regtype, 7))
 222                         config->type = REGULATOR_VOLTAGE;
 223                 else if (!strncmp("current", regtype, 7))
 224                         config->type = REGULATOR_CURRENT;
 225                 else
 226                         dev_warn(dev, "Unknown regulator-type '%s'\n",
 227                                  regtype);
 228         }
 229
 230         return config;
 231 }
 232
 233 static struct regulator_ops gpio_regulator_current_ops = {
 234         .get_current_limit = gpio_regulator_get_value,
 235         .set_current_limit = gpio_regulator_set_current_limit,
 236 };
 237
 238 static int gpio_regulator_probe(struct platform_device *pdev)
 239 {
 240         struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
 241         struct device_node *np = pdev->dev.of_node;
 242         struct gpio_regulator_data *drvdata;
 243         struct regulator_config cfg = { };
 244         int ptr, ret, state;
 245
 246         if (np) {
 247                 config = of_get_gpio_regulator_config(&pdev->dev, np);
 248                 if (IS_ERR(config))
 249                         return PTR_ERR(config);
 250         }
 251
 252         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
 253                                GFP_KERNEL);
 254         if (drvdata == NULL)
 255                 return -ENOMEM;
 256
 257         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 258         if (drvdata->desc.name == NULL) {
 259                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 260                 ret = -ENOMEM;
 261                 goto err;
 262         }
 263
 264         drvdata->gpios = kmemdup(config->gpios,
 265                                  config->nr_gpios * sizeof(struct gpio),
 266                                  GFP_KERNEL);
 267         if (drvdata->gpios == NULL) {
 268                 dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 269                 ret = -ENOMEM;
 270                 goto err_name;
 271         }
 272
 273         drvdata->states = kmemdup(config->states,
 274                                   config->nr_states *
 275                                          sizeof(struct gpio_regulator_state),
 276                                   GFP_KERNEL);
 277         if (drvdata->states == NULL) {
 278                 dev_err(&pdev->dev, "Failed to allocate state data\n");
 279                 ret = -ENOMEM;
 280                 goto err_memgpio;
 281         }
 282         drvdata->nr_states = config->nr_states;
 283
 284         drvdata->desc.owner = THIS_MODULE;
 285         drvdata->desc.enable_time = config->startup_delay;
 286
 287         /* handle regulator type*/
 288         switch (config->type) {
 289         case REGULATOR_VOLTAGE:
 290                 drvdata->desc.type = REGULATOR_VOLTAGE;
 291                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
 292                 drvdata->desc.n_voltages = config->nr_states;
 293                 break;
 294         case REGULATOR_CURRENT:
 295                 drvdata->desc.type = REGULATOR_CURRENT;
 296                 drvdata->desc.ops = &gpio_regulator_current_ops;
 297                 break;
 298         default:
 299                 dev_err(&pdev->dev, "No regulator type set\n");
 300                 ret = -EINVAL;
 301                 goto err_memgpio;
 302         }
 303
 304         drvdata->nr_gpios = config->nr_gpios;
 305         ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 306         if (ret) {
 307                 dev_err(&pdev->dev,
 308                    "Could not obtain regulator setting GPIOs: %d\n", ret);
 309                 goto err_memstate;
 310         }
 311
 312         /* build initial state from gpio init data. */
 313         state = 0;
 314         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 315                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 316                         state |= (1 << ptr);
 317         }
 318         drvdata->state = state;
 319
 320         cfg.dev = &pdev->dev;
 321         cfg.init_data = config->init_data;
 322         cfg.driver_data = drvdata;
 323         cfg.of_node = np;
 324
 325         if (config->enable_gpio >= 0)
 326                 cfg.ena_gpio = config->enable_gpio;
 327         cfg.ena_gpio_invert = !config->enable_high;
 328         if (config->enabled_at_boot) {
 329                 if (config->enable_high)
 330                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 331                 else
 332                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 333         } else {
 334                 if (config->enable_high)
 335                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 336                 else
 337                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 338         }
 339
 340         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 341         if (IS_ERR(drvdata->dev)) {
 342                 ret = PTR_ERR(drvdata->dev);
 343                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 344                 goto err_stategpio;
 345         }
 346
 347         platform_set_drvdata(pdev, drvdata);
 348
 349         return 0;
 350
 351 err_stategpio:
 352         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 353 err_memstate:
 354         kfree(drvdata->states);
 355 err_memgpio:
 356         kfree(drvdata->gpios);
 357 err_name:
 358         kfree(drvdata->desc.name);
 359 err:
 360         return ret;
 361 }
 362
 363 static int gpio_regulator_remove(struct platform_device *pdev)
 364 {
 365         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 366
 367         regulator_unregister(drvdata->dev);
 368
 369         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 370
 371         kfree(drvdata->states);
 372         kfree(drvdata->gpios);
 373
 374         kfree(drvdata->desc.name);
 375
 376         return 0;
 377 }
 378
 379 #if defined(CONFIG_OF)
 380 static const struct of_device_id regulator_gpio_of_match[] = {
 381         { .compatible = "regulator-gpio", },
 382         {},
 383 };
 384 #endif
 385
 386 static struct platform_driver gpio_regulator_driver = {
 387         .probe          = gpio_regulator_probe,
 388         .remove         = gpio_regulator_remove,
 389         .driver         = {
 390                 .name           = "gpio-regulator",
 391                 .owner          = THIS_MODULE,
 392                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
 393         },
 394 };
 395
 396 static int __init gpio_regulator_init(void)
 397 {
 398         return platform_driver_register(&gpio_regulator_driver);
 399 }
 400 subsys_initcall(gpio_regulator_init);
 401
 402 static void __exit gpio_regulator_exit(void)
 403 {
 404         platform_driver_unregister(&gpio_regulator_driver);
 405 }
 406 module_exit(gpio_regulator_exit);
 407
 408 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 409 MODULE_DESCRIPTION("gpio voltage regulator");
 410 MODULE_LICENSE("GPL");
 411 MODULE_ALIAS("platform:gpio-regulator");