drivers/regulator/fixed.c

   1 /*
   2  * fixed.c
   3  *
   4  * Copyright 2008 Wolfson Microelectronics PLC.
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of the
  11  * License, or (at your option) any later version.
  12  *
  13  * This is useful for systems with mixed controllable and
  14  * non-controllable regulators, as well as for allowing testing on
  15  * systems with no controllable regulators.
  16  */
  17
  18 #include <linux/err.h>
  19 #include <linux/mutex.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/regulator/driver.h>
  22 #include <linux/regulator/fixed.h>
  23
  24 struct fixed_voltage_data {
  25         struct regulator_desc desc;
  26         struct regulator_dev *dev;
  27         int microvolts;
  28 };
  29
  30 static int fixed_voltage_is_enabled(struct regulator_dev *dev)
  31 {
  32         return 1;
  33 }
  34
  35 static int fixed_voltage_enable(struct regulator_dev *dev)
  36 {
  37         return 0;
  38 }
  39
  40 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
  41 {
  42         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
  43
  44         return data->microvolts;
  45 }
  46
  47 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
  48                                       unsigned selector)
  49 {
  50         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
  51
  52         if (selector != 0)
  53                 return -EINVAL;
  54
  55         return data->microvolts;
  56 }
  57
  58 static struct regulator_ops fixed_voltage_ops = {
  59         .is_enabled = fixed_voltage_is_enabled,
  60         .enable = fixed_voltage_enable,
  61         .get_voltage = fixed_voltage_get_voltage,
  62         .list_voltage = fixed_voltage_list_voltage,
  63 };
  64
  65 static int regulator_fixed_voltage_probe(struct platform_device *pdev)
  66 {
  67         struct fixed_voltage_config *config = pdev->dev.platform_data;
  68         struct fixed_voltage_data *drvdata;
  69         int ret;
  70
  71         drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
  72         if (drvdata == NULL) {
  73                 ret = -ENOMEM;
  74                 goto err;
  75         }
  76
  77         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
  78         if (drvdata->desc.name == NULL) {
  79                 ret = -ENOMEM;
  80                 goto err;
  81         }
  82         drvdata->desc.type = REGULATOR_VOLTAGE;
  83         drvdata->desc.owner = THIS_MODULE;
  84         drvdata->desc.ops = &fixed_voltage_ops;
  85         drvdata->desc.n_voltages = 1;
  86
  87         drvdata->microvolts = config->microvolts;
  88
  89         drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
  90                                           config->init_data, drvdata);
  91         if (IS_ERR(drvdata->dev)) {
  92                 ret = PTR_ERR(drvdata->dev);
  93                 goto err_name;
  94         }
  95
  96         platform_set_drvdata(pdev, drvdata);
  97
  98         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
  99                 drvdata->microvolts);
 100
 101         return 0;
 102
 103 err_name:
 104         kfree(drvdata->desc.name);
 105 err:
 106         kfree(drvdata);
 107         return ret;
 108 }
 109
 110 static int regulator_fixed_voltage_remove(struct platform_device *pdev)
 111 {
 112         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
 113
 114         regulator_unregister(drvdata->dev);
 115         kfree(drvdata->desc.name);
 116         kfree(drvdata);
 117
 118         return 0;
 119 }
 120
 121 static struct platform_driver regulator_fixed_voltage_driver = {
 122         .probe          = regulator_fixed_voltage_probe,
 123         .remove         = regulator_fixed_voltage_remove,
 124         .driver         = {
 125                 .name           = "reg-fixed-voltage",
 126         },
 127 };
 128
 129 static int __init regulator_fixed_voltage_init(void)
 130 {
 131         return platform_driver_register(&regulator_fixed_voltage_driver);
 132 }
 133 subsys_initcall(regulator_fixed_voltage_init);
 134
 135 static void __exit regulator_fixed_voltage_exit(void)
 136 {
 137         platform_driver_unregister(&regulator_fixed_voltage_driver);
 138 }
 139 module_exit(regulator_fixed_voltage_exit);
 140
 141 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 142 MODULE_DESCRIPTION("Fixed voltage regulator");
 143 MODULE_LICENSE("GPL");
 144 MODULE_ALIAS("platform:reg-fixed-voltage");