linux/drivers/regulator/gpio-regulator.c
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   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
  38struct 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
  51static 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
  63static 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
  92static 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
 103static 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
 129static 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
 135struct gpio_regulator_config *
 136of_get_gpio_regulator_config(struct device *dev, struct device_node *np)
 137{
 138        struct gpio_regulator_config *config;
 139        struct property *prop;
 140        const char *regtype;
 141        int proplen, gpio, i;
 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        for (i = 0; ; i++)
 167                if (of_get_named_gpio(np, "gpios", i) < 0)
 168                        break;
 169        config->nr_gpios = i;
 170
 171        config->gpios = devm_kzalloc(dev,
 172                                sizeof(struct gpio) * config->nr_gpios,
 173                                GFP_KERNEL);
 174        if (!config->gpios)
 175                return ERR_PTR(-ENOMEM);
 176
 177        for (i = 0; i < config->nr_gpios; i++) {
 178                gpio = of_get_named_gpio(np, "gpios", i);
 179                if (gpio < 0)
 180                        break;
 181                config->gpios[i].gpio = gpio;
 182        }
 183
 184        /* Fetch states. */
 185        prop = of_find_property(np, "states", NULL);
 186        if (!prop) {
 187                dev_err(dev, "No 'states' property found\n");
 188                return ERR_PTR(-EINVAL);
 189        }
 190
 191        proplen = prop->length / sizeof(int);
 192
 193        config->states = devm_kzalloc(dev,
 194                                sizeof(struct gpio_regulator_state)
 195                                * (proplen / 2),
 196                                GFP_KERNEL);
 197        if (!config->states)
 198                return ERR_PTR(-ENOMEM);
 199
 200        for (i = 0; i < proplen / 2; i++) {
 201                config->states[i].value =
 202                        be32_to_cpup((int *)prop->value + (i * 2));
 203                config->states[i].gpios =
 204                        be32_to_cpup((int *)prop->value + (i * 2 + 1));
 205        }
 206        config->nr_states = i;
 207
 208        of_property_read_string(np, "regulator-type", &regtype);
 209
 210        if (!strncmp("voltage", regtype, 7))
 211                config->type = REGULATOR_VOLTAGE;
 212        else if (!strncmp("current", regtype, 7))
 213                config->type = REGULATOR_CURRENT;
 214
 215        return config;
 216}
 217
 218static struct regulator_ops gpio_regulator_current_ops = {
 219        .get_current_limit = gpio_regulator_get_value,
 220        .set_current_limit = gpio_regulator_set_current_limit,
 221};
 222
 223static int gpio_regulator_probe(struct platform_device *pdev)
 224{
 225        struct gpio_regulator_config *config = pdev->dev.platform_data;
 226        struct device_node *np = pdev->dev.of_node;
 227        struct gpio_regulator_data *drvdata;
 228        struct regulator_config cfg = { };
 229        int ptr, ret, state;
 230
 231        if (np) {
 232                config = of_get_gpio_regulator_config(&pdev->dev, np);
 233                if (IS_ERR(config))
 234                        return PTR_ERR(config);
 235        }
 236
 237        drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
 238                               GFP_KERNEL);
 239        if (drvdata == NULL) {
 240                dev_err(&pdev->dev, "Failed to allocate device data\n");
 241                return -ENOMEM;
 242        }
 243
 244        drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 245        if (drvdata->desc.name == NULL) {
 246                dev_err(&pdev->dev, "Failed to allocate supply name\n");
 247                ret = -ENOMEM;
 248                goto err;
 249        }
 250
 251        drvdata->gpios = kmemdup(config->gpios,
 252                                 config->nr_gpios * sizeof(struct gpio),
 253                                 GFP_KERNEL);
 254        if (drvdata->gpios == NULL) {
 255                dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 256                ret = -ENOMEM;
 257                goto err_name;
 258        }
 259
 260        drvdata->states = kmemdup(config->states,
 261                                  config->nr_states *
 262                                         sizeof(struct gpio_regulator_state),
 263                                  GFP_KERNEL);
 264        if (drvdata->states == NULL) {
 265                dev_err(&pdev->dev, "Failed to allocate state data\n");
 266                ret = -ENOMEM;
 267                goto err_memgpio;
 268        }
 269        drvdata->nr_states = config->nr_states;
 270
 271        drvdata->desc.owner = THIS_MODULE;
 272        drvdata->desc.enable_time = config->startup_delay;
 273
 274        /* handle regulator type*/
 275        switch (config->type) {
 276        case REGULATOR_VOLTAGE:
 277                drvdata->desc.type = REGULATOR_VOLTAGE;
 278                drvdata->desc.ops = &gpio_regulator_voltage_ops;
 279                drvdata->desc.n_voltages = config->nr_states;
 280                break;
 281        case REGULATOR_CURRENT:
 282                drvdata->desc.type = REGULATOR_CURRENT;
 283                drvdata->desc.ops = &gpio_regulator_current_ops;
 284                break;
 285        default:
 286                dev_err(&pdev->dev, "No regulator type set\n");
 287                ret = -EINVAL;
 288                goto err_memgpio;
 289                break;
 290        }
 291
 292        drvdata->nr_gpios = config->nr_gpios;
 293        ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 294        if (ret) {
 295                dev_err(&pdev->dev,
 296                   "Could not obtain regulator setting GPIOs: %d\n", ret);
 297                goto err_memstate;
 298        }
 299
 300        /* build initial state from gpio init data. */
 301        state = 0;
 302        for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 303                if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 304                        state |= (1 << ptr);
 305        }
 306        drvdata->state = state;
 307
 308        cfg.dev = &pdev->dev;
 309        cfg.init_data = config->init_data;
 310        cfg.driver_data = drvdata;
 311        cfg.of_node = np;
 312
 313        if (config->enable_gpio >= 0)
 314                cfg.ena_gpio = config->enable_gpio;
 315        cfg.ena_gpio_invert = !config->enable_high;
 316        if (config->enabled_at_boot) {
 317                if (config->enable_high)
 318                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 319                else
 320                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 321        } else {
 322                if (config->enable_high)
 323                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 324                else
 325                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 326        }
 327
 328        drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 329        if (IS_ERR(drvdata->dev)) {
 330                ret = PTR_ERR(drvdata->dev);
 331                dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 332                goto err_stategpio;
 333        }
 334
 335        platform_set_drvdata(pdev, drvdata);
 336
 337        return 0;
 338
 339err_stategpio:
 340        gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 341err_memstate:
 342        kfree(drvdata->states);
 343err_memgpio:
 344        kfree(drvdata->gpios);
 345err_name:
 346        kfree(drvdata->desc.name);
 347err:
 348        return ret;
 349}
 350
 351static int gpio_regulator_remove(struct platform_device *pdev)
 352{
 353        struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 354
 355        regulator_unregister(drvdata->dev);
 356
 357        gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 358
 359        kfree(drvdata->states);
 360        kfree(drvdata->gpios);
 361
 362        kfree(drvdata->desc.name);
 363
 364        return 0;
 365}
 366
 367#if defined(CONFIG_OF)
 368static const struct of_device_id regulator_gpio_of_match[] = {
 369        { .compatible = "regulator-gpio", },
 370        {},
 371};
 372#endif
 373
 374static struct platform_driver gpio_regulator_driver = {
 375        .probe          = gpio_regulator_probe,
 376        .remove         = gpio_regulator_remove,
 377        .driver         = {
 378                .name           = "gpio-regulator",
 379                .owner          = THIS_MODULE,
 380                .of_match_table = of_match_ptr(regulator_gpio_of_match),
 381        },
 382};
 383
 384static int __init gpio_regulator_init(void)
 385{
 386        return platform_driver_register(&gpio_regulator_driver);
 387}
 388subsys_initcall(gpio_regulator_init);
 389
 390static void __exit gpio_regulator_exit(void)
 391{
 392        platform_driver_unregister(&gpio_regulator_driver);
 393}
 394module_exit(gpio_regulator_exit);
 395
 396MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 397MODULE_DESCRIPTION("gpio voltage regulator");
 398MODULE_LICENSE("GPL");
 399MODULE_ALIAS("platform:gpio-regulator");
 400
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