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/gpio-regulator.h>
  32#include <linux/gpio.h>
  33#include <linux/slab.h>
  34
  35struct gpio_regulator_data {
  36        struct regulator_desc desc;
  37        struct regulator_dev *dev;
  38
  39        struct gpio *gpios;
  40        int nr_gpios;
  41
  42        struct gpio_regulator_state *states;
  43        int nr_states;
  44
  45        int state;
  46};
  47
  48static int gpio_regulator_get_value(struct regulator_dev *dev)
  49{
  50        struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  51        int ptr;
  52
  53        for (ptr = 0; ptr < data->nr_states; ptr++)
  54                if (data->states[ptr].gpios == data->state)
  55                        return data->states[ptr].value;
  56
  57        return -EINVAL;
  58}
  59
  60static int gpio_regulator_set_voltage(struct regulator_dev *dev,
  61                                        int min_uV, int max_uV,
  62                                        unsigned *selector)
  63{
  64        struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  65        int ptr, target = 0, state, best_val = INT_MAX;
  66
  67        for (ptr = 0; ptr < data->nr_states; ptr++)
  68                if (data->states[ptr].value < best_val &&
  69                    data->states[ptr].value >= min_uV &&
  70                    data->states[ptr].value <= max_uV) {
  71                        target = data->states[ptr].gpios;
  72                        best_val = data->states[ptr].value;
  73                        if (selector)
  74                                *selector = ptr;
  75                }
  76
  77        if (best_val == INT_MAX)
  78                return -EINVAL;
  79
  80        for (ptr = 0; ptr < data->nr_gpios; ptr++) {
  81                state = (target & (1 << ptr)) >> ptr;
  82                gpio_set_value(data->gpios[ptr].gpio, state);
  83        }
  84        data->state = target;
  85
  86        return 0;
  87}
  88
  89static int gpio_regulator_list_voltage(struct regulator_dev *dev,
  90                                      unsigned selector)
  91{
  92        struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  93
  94        if (selector >= data->nr_states)
  95                return -EINVAL;
  96
  97        return data->states[selector].value;
  98}
  99
 100static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
 101                                        int min_uA, int max_uA)
 102{
 103        struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 104        int ptr, target = 0, state, best_val = 0;
 105
 106        for (ptr = 0; ptr < data->nr_states; ptr++)
 107                if (data->states[ptr].value > best_val &&
 108                    data->states[ptr].value >= min_uA &&
 109                    data->states[ptr].value <= max_uA) {
 110                        target = data->states[ptr].gpios;
 111                        best_val = data->states[ptr].value;
 112                }
 113
 114        if (best_val == 0)
 115                return -EINVAL;
 116
 117        for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 118                state = (target & (1 << ptr)) >> ptr;
 119                gpio_set_value(data->gpios[ptr].gpio, state);
 120        }
 121        data->state = target;
 122
 123        return 0;
 124}
 125
 126static struct regulator_ops gpio_regulator_voltage_ops = {
 127        .get_voltage = gpio_regulator_get_value,
 128        .set_voltage = gpio_regulator_set_voltage,
 129        .list_voltage = gpio_regulator_list_voltage,
 130};
 131
 132static struct regulator_ops gpio_regulator_current_ops = {
 133        .get_current_limit = gpio_regulator_get_value,
 134        .set_current_limit = gpio_regulator_set_current_limit,
 135};
 136
 137static int __devinit gpio_regulator_probe(struct platform_device *pdev)
 138{
 139        struct gpio_regulator_config *config = pdev->dev.platform_data;
 140        struct gpio_regulator_data *drvdata;
 141        struct regulator_config cfg = { };
 142        int ptr, ret, state;
 143
 144        drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
 145                               GFP_KERNEL);
 146        if (drvdata == NULL) {
 147                dev_err(&pdev->dev, "Failed to allocate device data\n");
 148                return -ENOMEM;
 149        }
 150
 151        drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 152        if (drvdata->desc.name == NULL) {
 153                dev_err(&pdev->dev, "Failed to allocate supply name\n");
 154                ret = -ENOMEM;
 155                goto err;
 156        }
 157
 158        drvdata->gpios = kmemdup(config->gpios,
 159                                 config->nr_gpios * sizeof(struct gpio),
 160                                 GFP_KERNEL);
 161        if (drvdata->gpios == NULL) {
 162                dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 163                ret = -ENOMEM;
 164                goto err_name;
 165        }
 166
 167        drvdata->states = kmemdup(config->states,
 168                                  config->nr_states *
 169                                         sizeof(struct gpio_regulator_state),
 170                                  GFP_KERNEL);
 171        if (drvdata->states == NULL) {
 172                dev_err(&pdev->dev, "Failed to allocate state data\n");
 173                ret = -ENOMEM;
 174                goto err_memgpio;
 175        }
 176        drvdata->nr_states = config->nr_states;
 177
 178        drvdata->desc.owner = THIS_MODULE;
 179        drvdata->desc.enable_time = config->startup_delay;
 180
 181        /* handle regulator type*/
 182        switch (config->type) {
 183        case REGULATOR_VOLTAGE:
 184                drvdata->desc.type = REGULATOR_VOLTAGE;
 185                drvdata->desc.ops = &gpio_regulator_voltage_ops;
 186                drvdata->desc.n_voltages = config->nr_states;
 187                break;
 188        case REGULATOR_CURRENT:
 189                drvdata->desc.type = REGULATOR_CURRENT;
 190                drvdata->desc.ops = &gpio_regulator_current_ops;
 191                break;
 192        default:
 193                dev_err(&pdev->dev, "No regulator type set\n");
 194                ret = -EINVAL;
 195                goto err_memgpio;
 196                break;
 197        }
 198
 199        drvdata->nr_gpios = config->nr_gpios;
 200        ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 201        if (ret) {
 202                dev_err(&pdev->dev,
 203                   "Could not obtain regulator setting GPIOs: %d\n", ret);
 204                goto err_memstate;
 205        }
 206
 207        /* build initial state from gpio init data. */
 208        state = 0;
 209        for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 210                if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 211                        state |= (1 << ptr);
 212        }
 213        drvdata->state = state;
 214
 215        cfg.dev = &pdev->dev;
 216        cfg.init_data = config->init_data;
 217        cfg.driver_data = drvdata;
 218
 219        if (config->enable_gpio >= 0)
 220                cfg.ena_gpio = config->enable_gpio;
 221        cfg.ena_gpio_invert = !config->enable_high;
 222        if (config->enabled_at_boot) {
 223                if (config->enable_high)
 224                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 225                else
 226                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 227        } else {
 228                if (config->enable_high)
 229                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 230                else
 231                        cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 232        }
 233
 234        drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 235        if (IS_ERR(drvdata->dev)) {
 236                ret = PTR_ERR(drvdata->dev);
 237                dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 238                goto err_stategpio;
 239        }
 240
 241        platform_set_drvdata(pdev, drvdata);
 242
 243        return 0;
 244
 245err_stategpio:
 246        gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 247err_memstate:
 248        kfree(drvdata->states);
 249err_memgpio:
 250        kfree(drvdata->gpios);
 251err_name:
 252        kfree(drvdata->desc.name);
 253err:
 254        return ret;
 255}
 256
 257static int __devexit gpio_regulator_remove(struct platform_device *pdev)
 258{
 259        struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 260
 261        regulator_unregister(drvdata->dev);
 262
 263        gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 264
 265        kfree(drvdata->states);
 266        kfree(drvdata->gpios);
 267
 268        kfree(drvdata->desc.name);
 269
 270        return 0;
 271}
 272
 273static struct platform_driver gpio_regulator_driver = {
 274        .probe          = gpio_regulator_probe,
 275        .remove         = __devexit_p(gpio_regulator_remove),
 276        .driver         = {
 277                .name           = "gpio-regulator",
 278                .owner          = THIS_MODULE,
 279        },
 280};
 281
 282static int __init gpio_regulator_init(void)
 283{
 284        return platform_driver_register(&gpio_regulator_driver);
 285}
 286subsys_initcall(gpio_regulator_init);
 287
 288static void __exit gpio_regulator_exit(void)
 289{
 290        platform_driver_unregister(&gpio_regulator_driver);
 291}
 292module_exit(gpio_regulator_exit);
 293
 294MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 295MODULE_DESCRIPTION("gpio voltage regulator");
 296MODULE_LICENSE("GPL");
 297MODULE_ALIAS("platform:gpio-regulator");
 298
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