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/consumer.h>
  34 #include <linux/slab.h>
  35 #include <linux/of.h>
  36
  37 struct gpio_regulator_data {
  38         struct regulator_desc desc;
  39         struct regulator_dev *dev;
  40
  41         struct gpio_desc **gpiods;
  42         int nr_gpios;
  43
  44         struct gpio_regulator_state *states;
  45         int nr_states;
  46
  47         int state;
  48 };
  49
  50 static int gpio_regulator_get_value(struct regulator_dev *dev)
  51 {
  52         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  53         int ptr;
  54
  55         for (ptr = 0; ptr < data->nr_states; ptr++)
  56                 if (data->states[ptr].gpios == data->state)
  57                         return data->states[ptr].value;
  58
  59         return -EINVAL;
  60 }
  61
  62 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
  63                                         int min_uV, int max_uV,
  64                                         unsigned *selector)
  65 {
  66         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  67         int ptr, target = 0, state, best_val = INT_MAX;
  68
  69         for (ptr = 0; ptr < data->nr_states; ptr++)
  70                 if (data->states[ptr].value < best_val &&
  71                     data->states[ptr].value >= min_uV &&
  72                     data->states[ptr].value <= max_uV) {
  73                         target = data->states[ptr].gpios;
  74                         best_val = data->states[ptr].value;
  75                         if (selector)
  76                                 *selector = ptr;
  77                 }
  78
  79         if (best_val == INT_MAX)
  80                 return -EINVAL;
  81
  82         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
  83                 state = (target & (1 << ptr)) >> ptr;
  84                 gpiod_set_value_cansleep(data->gpiods[ptr], state);
  85         }
  86         data->state = target;
  87
  88         return 0;
  89 }
  90
  91 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
  92                                       unsigned selector)
  93 {
  94         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  95
  96         if (selector >= data->nr_states)
  97                 return -EINVAL;
  98
  99         return data->states[selector].value;
 100 }
 101
 102 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
 103                                         int min_uA, int max_uA)
 104 {
 105         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 106         int ptr, target = 0, state, best_val = 0;
 107
 108         for (ptr = 0; ptr < data->nr_states; ptr++)
 109                 if (data->states[ptr].value > best_val &&
 110                     data->states[ptr].value >= min_uA &&
 111                     data->states[ptr].value <= max_uA) {
 112                         target = data->states[ptr].gpios;
 113                         best_val = data->states[ptr].value;
 114                 }
 115
 116         if (best_val == 0)
 117                 return -EINVAL;
 118
 119         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 120                 state = (target & (1 << ptr)) >> ptr;
 121                 gpiod_set_value_cansleep(data->gpiods[ptr], state);
 122         }
 123         data->state = target;
 124
 125         return 0;
 126 }
 127
 128 static struct regulator_ops gpio_regulator_voltage_ops = {
 129         .get_voltage = gpio_regulator_get_value,
 130         .set_voltage = gpio_regulator_set_voltage,
 131         .list_voltage = gpio_regulator_list_voltage,
 132 };
 133
 134 static struct gpio_regulator_config *
 135 of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
 136                              const struct regulator_desc *desc)
 137 {
 138         struct gpio_regulator_config *config;
 139         const char *regtype;
 140         int proplen, i;
 141         int ngpios;
 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-at-boot"))
 157                 config->enabled_at_boot = true;
 158
 159         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 160
 161         /* Fetch GPIO init levels */
 162         ngpios = gpiod_count(dev, NULL);
 163         if (ngpios > 0) {
 164                 config->gflags = devm_kzalloc(dev,
 165                                               sizeof(enum gpiod_flags)
 166                                               * ngpios,
 167                                               GFP_KERNEL);
 168                 if (!config->gflags)
 169                         return ERR_PTR(-ENOMEM);
 170
 171                 for (i = 0; i < ngpios; i++) {
 172                         u32 val;
 173
 174                         ret = of_property_read_u32_index(np, "gpios-states", i,
 175                                                          &val);
 176
 177                         /* Default to high per specification */
 178                         if (ret)
 179                                 config->gflags[i] = GPIOD_OUT_HIGH;
 180                         else
 181                                 config->gflags[i] =
 182                                         val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
 183                 }
 184         }
 185         config->ngpios = ngpios;
 186
 187         /* Fetch states. */
 188         proplen = of_property_count_u32_elems(np, "states");
 189         if (proplen < 0) {
 190                 dev_err(dev, "No 'states' property found\n");
 191                 return ERR_PTR(-EINVAL);
 192         }
 193
 194         config->states = devm_kcalloc(dev,
 195                                 proplen / 2,
 196                                 sizeof(struct gpio_regulator_state),
 197                                 GFP_KERNEL);
 198         if (!config->states)
 199                 return ERR_PTR(-ENOMEM);
 200
 201         for (i = 0; i < proplen / 2; i++) {
 202                 of_property_read_u32_index(np, "states", i * 2,
 203                                            &config->states[i].value);
 204                 of_property_read_u32_index(np, "states", i * 2 + 1,
 205                                            &config->states[i].gpios);
 206         }
 207         config->nr_states = i;
 208
 209         config->type = REGULATOR_VOLTAGE;
 210         ret = of_property_read_string(np, "regulator-type", &regtype);
 211         if (ret >= 0) {
 212                 if (!strncmp("voltage", regtype, 7))
 213                         config->type = REGULATOR_VOLTAGE;
 214                 else if (!strncmp("current", regtype, 7))
 215                         config->type = REGULATOR_CURRENT;
 216                 else
 217                         dev_warn(dev, "Unknown regulator-type '%s'\n",
 218                                  regtype);
 219         }
 220
 221         return config;
 222 }
 223
 224 static struct regulator_ops gpio_regulator_current_ops = {
 225         .get_current_limit = gpio_regulator_get_value,
 226         .set_current_limit = gpio_regulator_set_current_limit,
 227 };
 228
 229 static int gpio_regulator_probe(struct platform_device *pdev)
 230 {
 231         struct device *dev = &pdev->dev;
 232         struct gpio_regulator_config *config = dev_get_platdata(dev);
 233         struct device_node *np = dev->of_node;
 234         struct gpio_regulator_data *drvdata;
 235         struct regulator_config cfg = { };
 236         enum gpiod_flags gflags;
 237         int ptr, ret, state, i;
 238
 239         drvdata = devm_kzalloc(dev, sizeof(struct gpio_regulator_data),
 240                                GFP_KERNEL);
 241         if (drvdata == NULL)
 242                 return -ENOMEM;
 243
 244         if (np) {
 245                 config = of_get_gpio_regulator_config(dev, np,
 246                                                       &drvdata->desc);
 247                 if (IS_ERR(config))
 248                         return PTR_ERR(config);
 249         }
 250
 251         drvdata->desc.name = devm_kstrdup(dev, config->supply_name, GFP_KERNEL);
 252         if (drvdata->desc.name == NULL) {
 253                 dev_err(dev, "Failed to allocate supply name\n");
 254                 return -ENOMEM;
 255         }
 256
 257         drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
 258                                        GFP_KERNEL);
 259         if (!drvdata->gpiods)
 260                 return -ENOMEM;
 261         for (i = 0; i < config->ngpios; i++) {
 262                 drvdata->gpiods[i] = devm_gpiod_get_index(dev,
 263                                                           NULL,
 264                                                           i,
 265                                                           config->gflags[i]);
 266                 if (IS_ERR(drvdata->gpiods[i]))
 267                         return PTR_ERR(drvdata->gpiods[i]);
 268                 /* This is good to know */
 269                 gpiod_set_consumer_name(drvdata->gpiods[i], drvdata->desc.name);
 270         }
 271         drvdata->nr_gpios = config->ngpios;
 272
 273         drvdata->states = devm_kmemdup(dev,
 274                                        config->states,
 275                                        config->nr_states *
 276                                        sizeof(struct gpio_regulator_state),
 277                                        GFP_KERNEL);
 278         if (drvdata->states == NULL) {
 279                 dev_err(dev, "Failed to allocate state data\n");
 280                 return -ENOMEM;
 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(dev, "No regulator type set\n");
 300                 return -EINVAL;
 301         }
 302
 303         /* build initial state from gpio init data. */
 304         state = 0;
 305         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 306                 if (config->gflags[ptr] == GPIOD_OUT_HIGH)
 307                         state |= (1 << ptr);
 308         }
 309         drvdata->state = state;
 310
 311         cfg.dev = dev;
 312         cfg.init_data = config->init_data;
 313         cfg.driver_data = drvdata;
 314         cfg.of_node = np;
 315
 316         /*
 317          * The signal will be inverted by the GPIO core if flagged so in the
 318          * decriptor.
 319          */
 320         if (config->enabled_at_boot)
 321                 gflags = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 322         else
 323                 gflags = GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 324
 325         cfg.ena_gpiod = gpiod_get_optional(dev, "enable", gflags);
 326         if (IS_ERR(cfg.ena_gpiod))
 327                 return PTR_ERR(cfg.ena_gpiod);
 328
 329         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 330         if (IS_ERR(drvdata->dev)) {
 331                 ret = PTR_ERR(drvdata->dev);
 332                 dev_err(dev, "Failed to register regulator: %d\n", ret);
 333                 return ret;
 334         }
 335
 336         platform_set_drvdata(pdev, drvdata);
 337
 338         return 0;
 339 }
 340
 341 static int gpio_regulator_remove(struct platform_device *pdev)
 342 {
 343         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 344
 345         regulator_unregister(drvdata->dev);
 346
 347         return 0;
 348 }
 349
 350 #if defined(CONFIG_OF)
 351 static const struct of_device_id regulator_gpio_of_match[] = {
 352         { .compatible = "regulator-gpio", },
 353         {},
 354 };
 355 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
 356 #endif
 357
 358 static struct platform_driver gpio_regulator_driver = {
 359         .probe          = gpio_regulator_probe,
 360         .remove         = gpio_regulator_remove,
 361         .driver         = {
 362                 .name           = "gpio-regulator",
 363                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
 364         },
 365 };
 366
 367 static int __init gpio_regulator_init(void)
 368 {
 369         return platform_driver_register(&gpio_regulator_driver);
 370 }
 371 subsys_initcall(gpio_regulator_init);
 372
 373 static void __exit gpio_regulator_exit(void)
 374 {
 375         platform_driver_unregister(&gpio_regulator_driver);
 376 }
 377 module_exit(gpio_regulator_exit);
 378
 379 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 380 MODULE_DESCRIPTION("gpio voltage regulator");
 381 MODULE_LICENSE("GPL");
 382 MODULE_ALIAS("platform:gpio-regulator");