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   1 /*
   2  * fixed.c
   3  *
   4  * Copyright 2008 Wolfson Microelectronics PLC.
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  * Copyright (c) 2009 Nokia Corporation
   9  * Roger Quadros <ext-roger.quadros@nokia.com>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of the
  14  * License, or (at your option) any later version.
  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/platform_device.h>
  24 #include <linux/regulator/driver.h>
  25 #include <linux/regulator/fixed.h>
  26 #include <linux/gpio.h>
  27 #include <linux/delay.h>
  28 #include <linux/slab.h>
  29
  30 struct fixed_voltage_data {
  31         struct regulator_desc desc;
  32         struct regulator_dev *dev;
  33         int microvolts;
  34         int gpio;
  35         unsigned startup_delay;
  36         bool enable_high;
  37         bool is_enabled;
  38 };
  39
  40 static int fixed_voltage_is_enabled(struct regulator_dev *dev)
  41 {
  42         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
  43
  44         return data->is_enabled;
  45 }
  46
  47 static int fixed_voltage_enable(struct regulator_dev *dev)
  48 {
  49         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
  50
  51         if (gpio_is_valid(data->gpio)) {
  52                 gpio_set_value_cansleep(data->gpio, data->enable_high);
  53                 data->is_enabled = true;
  54         }
  55
  56         return 0;
  57 }
  58
  59 static int fixed_voltage_disable(struct regulator_dev *dev)
  60 {
  61         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
  62
  63         if (gpio_is_valid(data->gpio)) {
  64                 gpio_set_value_cansleep(data->gpio, !data->enable_high);
  65                 data->is_enabled = false;
  66         }
  67
  68         return 0;
  69 }
  70
  71 static int fixed_voltage_enable_time(struct regulator_dev *dev)
  72 {
  73         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
  74
  75         return data->startup_delay;
  76 }
  77
  78 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
  79 {
  80         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
  81
  82         return data->microvolts;
  83 }
  84
  85 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
  86                                       unsigned selector)
  87 {
  88         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
  89
  90         if (selector != 0)
  91                 return -EINVAL;
  92
  93         return data->microvolts;
  94 }
  95
  96 static struct regulator_ops fixed_voltage_ops = {
  97         .is_enabled = fixed_voltage_is_enabled,
  98         .enable = fixed_voltage_enable,
  99         .disable = fixed_voltage_disable,
 100         .enable_time = fixed_voltage_enable_time,
 101         .get_voltage = fixed_voltage_get_voltage,
 102         .list_voltage = fixed_voltage_list_voltage,
 103 };
 104
 105 static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
 106 {
 107         struct fixed_voltage_config *config = pdev->dev.platform_data;
 108         struct fixed_voltage_data *drvdata;
 109         int ret;
 110
 111         drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
 112         if (drvdata == NULL) {
 113                 dev_err(&pdev->dev, "Failed to allocate device data\n");
 114                 ret = -ENOMEM;
 115                 goto err;
 116         }
 117
 118         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 119         if (drvdata->desc.name == NULL) {
 120                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 121                 ret = -ENOMEM;
 122                 goto err;
 123         }
 124         drvdata->desc.type = REGULATOR_VOLTAGE;
 125         drvdata->desc.owner = THIS_MODULE;
 126         drvdata->desc.ops = &fixed_voltage_ops;
 127         drvdata->desc.n_voltages = 1;
 128
 129         drvdata->microvolts = config->microvolts;
 130         drvdata->gpio = config->gpio;
 131         drvdata->startup_delay = config->startup_delay;
 132
 133         if (gpio_is_valid(config->gpio)) {
 134                 drvdata->enable_high = config->enable_high;
 135
 136                 /* FIXME: Remove below print warning
 137                  *
 138                  * config->gpio must be set to -EINVAL by platform code if
 139                  * GPIO control is not required. However, early adopters
 140                  * not requiring GPIO control may forget to initialize
 141                  * config->gpio to -EINVAL. This will cause GPIO 0 to be used
 142                  * for GPIO control.
 143                  *
 144                  * This warning will be removed once there are a couple of users
 145                  * for this driver.
 146                  */
 147                 if (!config->gpio)
 148                         dev_warn(&pdev->dev,
 149                                 "using GPIO 0 for regulator enable control\n");
 150
 151                 ret = gpio_request(config->gpio, config->supply_name);
 152                 if (ret) {
 153                         dev_err(&pdev->dev,
 154                            "Could not obtain regulator enable GPIO %d: %d\n",
 155                                                         config->gpio, ret);
 156                         goto err_name;
 157                 }
 158
 159                 /* set output direction without changing state
 160                  * to prevent glitch
 161                  */
 162                 drvdata->is_enabled = config->enabled_at_boot;
 163                 ret = drvdata->is_enabled ?
 164                                 config->enable_high : !config->enable_high;
 165
 166                 ret = gpio_direction_output(config->gpio, ret);
 167                 if (ret) {
 168                         dev_err(&pdev->dev,
 169                            "Could not configure regulator enable GPIO %d direction: %d\n",
 170                                                         config->gpio, ret);
 171                         goto err_gpio;
 172                 }
 173
 174         } else {
 175                 /* Regulator without GPIO control is considered
 176                  * always enabled
 177                  */
 178                 drvdata->is_enabled = true;
 179         }
 180
 181         drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
 182                                           config->init_data, drvdata);
 183         if (IS_ERR(drvdata->dev)) {
 184                 ret = PTR_ERR(drvdata->dev);
 185                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 186                 goto err_gpio;
 187         }
 188
 189         platform_set_drvdata(pdev, drvdata);
 190
 191         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 192                 drvdata->microvolts);
 193
 194         return 0;
 195
 196 err_gpio:
 197         if (gpio_is_valid(config->gpio))
 198                 gpio_free(config->gpio);
 199 err_name:
 200         kfree(drvdata->desc.name);
 201 err:
 202         kfree(drvdata);
 203         return ret;
 204 }
 205
 206 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
 207 {
 208         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
 209
 210         regulator_unregister(drvdata->dev);
 211         if (gpio_is_valid(drvdata->gpio))
 212                 gpio_free(drvdata->gpio);
 213         kfree(drvdata->desc.name);
 214         kfree(drvdata);
 215
 216         return 0;
 217 }
 218
 219 static struct platform_driver regulator_fixed_voltage_driver = {
 220         .probe          = reg_fixed_voltage_probe,
 221         .remove         = __devexit_p(reg_fixed_voltage_remove),
 222         .driver         = {
 223                 .name           = "reg-fixed-voltage",
 224                 .owner          = THIS_MODULE,
 225         },
 226 };
 227
 228 static int __init regulator_fixed_voltage_init(void)
 229 {
 230         return platform_driver_register(&regulator_fixed_voltage_driver);
 231 }
 232 subsys_initcall(regulator_fixed_voltage_init);
 233
 234 static void __exit regulator_fixed_voltage_exit(void)
 235 {
 236         platform_driver_unregister(&regulator_fixed_voltage_driver);
 237 }
 238 module_exit(regulator_fixed_voltage_exit);
 239
 240 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 241 MODULE_DESCRIPTION("Fixed voltage regulator");
 242 MODULE_LICENSE("GPL");
 243 MODULE_ALIAS("platform:reg-fixed-voltage");