drivers/regulator/gpio-regulator.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * gpio-regulator.c
   4  *
   5  * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
   6  *
   7  * based on fixed.c
   8  *
   9  * Copyright 2008 Wolfson Microelectronics PLC.
  10  *
  11  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  12  *
  13  * Copyright (c) 2009 Nokia Corporation
  14  * Roger Quadros <ext-roger.quadros@nokia.com>
  15  *
  16  * This is useful for systems with mixed controllable and
  17  * non-controllable regulators, as well as for allowing testing on
  18  * systems with no controllable regulators.
  19  */
  20
  21 #include <linux/err.h>
  22 #include <linux/mutex.h>
  23 #include <linux/module.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/regulator/driver.h>
  26 #include <linux/regulator/machine.h>
  27 #include <linux/regulator/of_regulator.h>
  28 #include <linux/regulator/gpio-regulator.h>
  29 #include <linux/gpio/consumer.h>
  30 #include <linux/slab.h>
  31 #include <linux/of.h>
  32
  33 struct gpio_regulator_data {
  34         struct regulator_desc desc;
  35
  36         struct gpio_desc **gpiods;
  37         int nr_gpios;
  38
  39         struct gpio_regulator_state *states;
  40         int nr_states;
  41
  42         int state;
  43 };
  44
  45 static int gpio_regulator_get_value(struct regulator_dev *dev)
  46 {
  47         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  48         int ptr;
  49
  50         for (ptr = 0; ptr < data->nr_states; ptr++)
  51                 if (data->states[ptr].gpios == data->state)
  52                         return data->states[ptr].value;
  53
  54         return -EINVAL;
  55 }
  56
  57 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
  58                                         int min_uV, int max_uV,
  59                                         unsigned *selector)
  60 {
  61         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  62         int ptr, target = 0, state, best_val = INT_MAX;
  63
  64         for (ptr = 0; ptr < data->nr_states; ptr++)
  65                 if (data->states[ptr].value < best_val &&
  66                     data->states[ptr].value >= min_uV &&
  67                     data->states[ptr].value <= max_uV) {
  68                         target = data->states[ptr].gpios;
  69                         best_val = data->states[ptr].value;
  70                         if (selector)
  71                                 *selector = ptr;
  72                 }
  73
  74         if (best_val == INT_MAX)
  75                 return -EINVAL;
  76
  77         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
  78                 state = (target & (1 << ptr)) >> ptr;
  79                 gpiod_set_value_cansleep(data->gpiods[ptr], state);
  80         }
  81         data->state = target;
  82
  83         return 0;
  84 }
  85
  86 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
  87                                       unsigned selector)
  88 {
  89         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  90
  91         if (selector >= data->nr_states)
  92                 return -EINVAL;
  93
  94         return data->states[selector].value;
  95 }
  96
  97 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
  98                                         int min_uA, int max_uA)
  99 {
 100         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 101         int ptr, target = 0, state, best_val = 0;
 102
 103         for (ptr = 0; ptr < data->nr_states; ptr++)
 104                 if (data->states[ptr].value > best_val &&
 105                     data->states[ptr].value >= min_uA &&
 106                     data->states[ptr].value <= max_uA) {
 107                         target = data->states[ptr].gpios;
 108                         best_val = data->states[ptr].value;
 109                 }
 110
 111         if (best_val == 0)
 112                 return -EINVAL;
 113
 114         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 115                 state = (target & (1 << ptr)) >> ptr;
 116                 gpiod_set_value_cansleep(data->gpiods[ptr], state);
 117         }
 118         data->state = target;
 119
 120         return 0;
 121 }
 122
 123 static const struct regulator_ops gpio_regulator_voltage_ops = {
 124         .get_voltage = gpio_regulator_get_value,
 125         .set_voltage = gpio_regulator_set_voltage,
 126         .list_voltage = gpio_regulator_list_voltage,
 127 };
 128
 129 static struct gpio_regulator_config *
 130 of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
 131                              const struct regulator_desc *desc)
 132 {
 133         struct gpio_regulator_config *config;
 134         const char *regtype;
 135         int proplen, i;
 136         int ngpios;
 137         int ret;
 138
 139         config = devm_kzalloc(dev,
 140                         sizeof(struct gpio_regulator_config),
 141                         GFP_KERNEL);
 142         if (!config)
 143                 return ERR_PTR(-ENOMEM);
 144
 145         config->init_data = of_get_regulator_init_data(dev, np, desc);
 146         if (!config->init_data)
 147                 return ERR_PTR(-EINVAL);
 148
 149         config->supply_name = config->init_data->constraints.name;
 150
 151         if (config->init_data->constraints.boot_on)
 152                 config->enabled_at_boot = true;
 153
 154         /*
 155          * Do not use: undocumented device tree property.
 156          * This is kept around solely for device tree ABI stability.
 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         /* Fetch GPIO init levels */
 164         ngpios = gpiod_count(dev, NULL);
 165         if (ngpios > 0) {
 166                 config->gflags = devm_kzalloc(dev,
 167                                               sizeof(enum gpiod_flags)
 168                                               * ngpios,
 169                                               GFP_KERNEL);
 170                 if (!config->gflags)
 171                         return ERR_PTR(-ENOMEM);
 172
 173                 for (i = 0; i < ngpios; i++) {
 174                         u32 val;
 175
 176                         ret = of_property_read_u32_index(np, "gpios-states", i,
 177                                                          &val);
 178
 179                         /* Default to high per specification */
 180                         if (ret)
 181                                 config->gflags[i] = GPIOD_OUT_HIGH;
 182                         else
 183                                 config->gflags[i] =
 184                                         val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
 185                 }
 186         }
 187         config->ngpios = ngpios;
 188
 189         /* Fetch states. */
 190         proplen = of_property_count_u32_elems(np, "states");
 191         if (proplen < 0) {
 192                 dev_err(dev, "No 'states' property found\n");
 193                 return ERR_PTR(-EINVAL);
 194         }
 195
 196         config->states = devm_kcalloc(dev,
 197                                 proplen / 2,
 198                                 sizeof(struct gpio_regulator_state),
 199                                 GFP_KERNEL);
 200         if (!config->states)
 201                 return ERR_PTR(-ENOMEM);
 202
 203         for (i = 0; i < proplen / 2; i++) {
 204                 of_property_read_u32_index(np, "states", i * 2,
 205                                            &config->states[i].value);
 206                 of_property_read_u32_index(np, "states", i * 2 + 1,
 207                                            &config->states[i].gpios);
 208         }
 209         config->nr_states = i;
 210
 211         config->type = REGULATOR_VOLTAGE;
 212         ret = of_property_read_string(np, "regulator-type", &regtype);
 213         if (ret >= 0) {
 214                 if (!strncmp("voltage", regtype, 7))
 215                         config->type = REGULATOR_VOLTAGE;
 216                 else if (!strncmp("current", regtype, 7))
 217                         config->type = REGULATOR_CURRENT;
 218                 else
 219                         dev_warn(dev, "Unknown regulator-type '%s'\n",
 220                                  regtype);
 221         }
 222
 223         if (of_property_present(np, "vin-supply"))
 224                 config->input_supply = "vin";
 225
 226         return config;
 227 }
 228
 229 static const struct regulator_ops gpio_regulator_current_ops = {
 230         .get_current_limit = gpio_regulator_get_value,
 231         .set_current_limit = gpio_regulator_set_current_limit,
 232 };
 233
 234 static int gpio_regulator_probe(struct platform_device *pdev)
 235 {
 236         struct device *dev = &pdev->dev;
 237         struct gpio_regulator_config *config = dev_get_platdata(dev);
 238         struct device_node *np = dev->of_node;
 239         struct gpio_regulator_data *drvdata;
 240         struct regulator_config cfg = { };
 241         struct regulator_dev *rdev;
 242         enum gpiod_flags gflags;
 243         int ptr, ret, state, i;
 244
 245         drvdata = devm_kzalloc(dev, sizeof(struct gpio_regulator_data),
 246                                GFP_KERNEL);
 247         if (drvdata == NULL)
 248                 return -ENOMEM;
 249
 250         if (np) {
 251                 config = of_get_gpio_regulator_config(dev, np,
 252                                                       &drvdata->desc);
 253                 if (IS_ERR(config))
 254                         return PTR_ERR(config);
 255         }
 256
 257         drvdata->desc.name = devm_kstrdup(dev, config->supply_name, GFP_KERNEL);
 258         if (drvdata->desc.name == NULL) {
 259                 dev_err(dev, "Failed to allocate supply name\n");
 260                 return -ENOMEM;
 261         }
 262
 263         drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
 264                                        GFP_KERNEL);
 265
 266         if (config->input_supply) {
 267                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 268                                                          config->input_supply,
 269                                                          GFP_KERNEL);
 270                 if (!drvdata->desc.supply_name) {
 271                         dev_err(&pdev->dev,
 272                                 "Failed to allocate input supply\n");
 273                         return -ENOMEM;
 274                 }
 275         }
 276
 277         if (!drvdata->gpiods)
 278                 return -ENOMEM;
 279         for (i = 0; i < config->ngpios; i++) {
 280                 drvdata->gpiods[i] = devm_gpiod_get_index(dev,
 281                                                           NULL,
 282                                                           i,
 283                                                           config->gflags[i]);
 284                 if (IS_ERR(drvdata->gpiods[i]))
 285                         return PTR_ERR(drvdata->gpiods[i]);
 286                 /* This is good to know */
 287                 gpiod_set_consumer_name(drvdata->gpiods[i], drvdata->desc.name);
 288         }
 289         drvdata->nr_gpios = config->ngpios;
 290
 291         drvdata->states = devm_kmemdup(dev,
 292                                        config->states,
 293                                        config->nr_states *
 294                                        sizeof(struct gpio_regulator_state),
 295                                        GFP_KERNEL);
 296         if (drvdata->states == NULL) {
 297                 dev_err(dev, "Failed to allocate state data\n");
 298                 return -ENOMEM;
 299         }
 300         drvdata->nr_states = config->nr_states;
 301
 302         drvdata->desc.owner = THIS_MODULE;
 303         drvdata->desc.enable_time = config->startup_delay;
 304
 305         /* handle regulator type*/
 306         switch (config->type) {
 307         case REGULATOR_VOLTAGE:
 308                 drvdata->desc.type = REGULATOR_VOLTAGE;
 309                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
 310                 drvdata->desc.n_voltages = config->nr_states;
 311                 break;
 312         case REGULATOR_CURRENT:
 313                 drvdata->desc.type = REGULATOR_CURRENT;
 314                 drvdata->desc.ops = &gpio_regulator_current_ops;
 315                 break;
 316         default:
 317                 dev_err(dev, "No regulator type set\n");
 318                 return -EINVAL;
 319         }
 320
 321         /* build initial state from gpio init data. */
 322         state = 0;
 323         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 324                 if (config->gflags[ptr] == GPIOD_OUT_HIGH)
 325                         state |= (1 << ptr);
 326         }
 327         drvdata->state = state;
 328
 329         cfg.dev = dev;
 330         cfg.init_data = config->init_data;
 331         cfg.driver_data = drvdata;
 332         cfg.of_node = np;
 333
 334         /*
 335          * The signal will be inverted by the GPIO core if flagged so in the
 336          * descriptor.
 337          */
 338         if (config->enabled_at_boot)
 339                 gflags = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 340         else
 341                 gflags = GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 342
 343         cfg.ena_gpiod = gpiod_get_optional(dev, "enable", gflags);
 344         if (IS_ERR(cfg.ena_gpiod))
 345                 return PTR_ERR(cfg.ena_gpiod);
 346
 347         rdev = devm_regulator_register(dev, &drvdata->desc, &cfg);
 348         if (IS_ERR(rdev)) {
 349                 ret = PTR_ERR(rdev);
 350                 dev_err(dev, "Failed to register regulator: %d\n", ret);
 351                 return ret;
 352         }
 353
 354         platform_set_drvdata(pdev, drvdata);
 355
 356         return 0;
 357 }
 358
 359 #if defined(CONFIG_OF)
 360 static const struct of_device_id regulator_gpio_of_match[] = {
 361         { .compatible = "regulator-gpio", },
 362         {},
 363 };
 364 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
 365 #endif
 366
 367 static struct platform_driver gpio_regulator_driver = {
 368         .probe          = gpio_regulator_probe,
 369         .driver         = {
 370                 .name           = "gpio-regulator",
 371                 .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
 372                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
 373         },
 374 };
 375
 376 static int __init gpio_regulator_init(void)
 377 {
 378         return platform_driver_register(&gpio_regulator_driver);
 379 }
 380 subsys_initcall(gpio_regulator_init);
 381
 382 static void __exit gpio_regulator_exit(void)
 383 {
 384         platform_driver_unregister(&gpio_regulator_driver);
 385 }
 386 module_exit(gpio_regulator_exit);
 387
 388 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 389 MODULE_DESCRIPTION("gpio voltage regulator");
 390 MODULE_LICENSE("GPL");
 391 MODULE_ALIAS("platform:gpio-regulator");