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