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/gpio-regulator.h>
  32 #include <linux/gpio.h>
  33 #include <linux/slab.h>
  34
  35 struct 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
  48 static 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
  60 static 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
  89 static 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
 100 static 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
 126 static 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
 132 static 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
 137 static 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
 245 err_stategpio:
 246         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 247 err_memstate:
 248         kfree(drvdata->states);
 249 err_memgpio:
 250         kfree(drvdata->gpios);
 251 err_name:
 252         kfree(drvdata->desc.name);
 253 err:
 254         return ret;
 255 }
 256
 257 static 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
 273 static 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
 282 static int __init gpio_regulator_init(void)
 283 {
 284         return platform_driver_register(&gpio_regulator_driver);
 285 }
 286 subsys_initcall(gpio_regulator_init);
 287
 288 static void __exit gpio_regulator_exit(void)
 289 {
 290         platform_driver_unregister(&gpio_regulator_driver);
 291 }
 292 module_exit(gpio_regulator_exit);
 293
 294 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 295 MODULE_DESCRIPTION("gpio voltage regulator");
 296 MODULE_LICENSE("GPL");
 297 MODULE_ALIAS("platform:gpio-regulator");