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  * 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/module.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/regulator/driver.h>
  26 #include <linux/regulator/fixed.h>
  27 #include <linux/gpio.h>
  28 #include <linux/slab.h>
  29 #include <linux/of.h>
  30 #include <linux/of_gpio.h>
  31 #include <linux/regulator/of_regulator.h>
  32 #include <linux/regulator/machine.h>
  33
  34 struct fixed_voltage_data {
  35         struct regulator_desc desc;
  36         struct regulator_dev *dev;
  37 };
  38
  39
  40 /**
  41  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
  42  * @dev: device requesting for fixed_voltage_config
  43  * @desc: regulator description
  44  *
  45  * Populates fixed_voltage_config structure by extracting data from device
  46  * tree node, returns a pointer to the populated structure of NULL if memory
  47  * alloc fails.
  48  */
  49 static struct fixed_voltage_config *
  50 of_get_fixed_voltage_config(struct device *dev,
  51                             const struct regulator_desc *desc)
  52 {
  53         struct fixed_voltage_config *config;
  54         struct device_node *np = dev->of_node;
  55         struct regulator_init_data *init_data;
  56
  57         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
  58                                                                  GFP_KERNEL);
  59         if (!config)
  60                 return ERR_PTR(-ENOMEM);
  61
  62         config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
  63         if (!config->init_data)
  64                 return ERR_PTR(-EINVAL);
  65
  66         init_data = config->init_data;
  67         init_data->constraints.apply_uV = 0;
  68
  69         config->supply_name = init_data->constraints.name;
  70         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
  71                 config->microvolts = init_data->constraints.min_uV;
  72         } else {
  73                 dev_err(dev,
  74                          "Fixed regulator specified with variable voltages\n");
  75                 return ERR_PTR(-EINVAL);
  76         }
  77
  78         if (init_data->constraints.boot_on)
  79                 config->enabled_at_boot = true;
  80
  81         config->gpio = of_get_named_gpio(np, "gpio", 0);
  82         /*
  83          * of_get_named_gpio() currently returns ENODEV rather than
  84          * EPROBE_DEFER. This code attempts to be compatible with both
  85          * for now; the ENODEV check can be removed once the API is fixed.
  86          * of_get_named_gpio() doesn't differentiate between a missing
  87          * property (which would be fine here, since the GPIO is optional)
  88          * and some other error. Patches have been posted for both issues.
  89          * Once they are check in, we should replace this with:
  90          * if (config->gpio < 0 && config->gpio != -ENOENT)
  91          */
  92         if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER))
  93                 return ERR_PTR(-EPROBE_DEFER);
  94
  95         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
  96
  97         config->enable_high = of_property_read_bool(np, "enable-active-high");
  98         config->gpio_is_open_drain = of_property_read_bool(np,
  99                                                            "gpio-open-drain");
 100
 101         if (of_find_property(np, "vin-supply", NULL))
 102                 config->input_supply = "vin";
 103
 104         return config;
 105 }
 106
 107 static struct regulator_ops fixed_voltage_ops = {
 108 };
 109
 110 static int reg_fixed_voltage_probe(struct platform_device *pdev)
 111 {
 112         struct fixed_voltage_config *config;
 113         struct fixed_voltage_data *drvdata;
 114         struct regulator_config cfg = { };
 115         int ret;
 116
 117         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 118                                GFP_KERNEL);
 119         if (!drvdata)
 120                 return -ENOMEM;
 121
 122         if (pdev->dev.of_node) {
 123                 config = of_get_fixed_voltage_config(&pdev->dev,
 124                                                      &drvdata->desc);
 125                 if (IS_ERR(config))
 126                         return PTR_ERR(config);
 127         } else {
 128                 config = dev_get_platdata(&pdev->dev);
 129         }
 130
 131         if (!config)
 132                 return -ENOMEM;
 133
 134         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 135                                           config->supply_name,
 136                                           GFP_KERNEL);
 137         if (drvdata->desc.name == NULL) {
 138                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 139                 return -ENOMEM;
 140         }
 141         drvdata->desc.type = REGULATOR_VOLTAGE;
 142         drvdata->desc.owner = THIS_MODULE;
 143         drvdata->desc.ops = &fixed_voltage_ops;
 144
 145         drvdata->desc.enable_time = config->startup_delay;
 146
 147         if (config->input_supply) {
 148                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 149                                             config->input_supply,
 150                                             GFP_KERNEL);
 151                 if (!drvdata->desc.supply_name) {
 152                         dev_err(&pdev->dev,
 153                                 "Failed to allocate input supply\n");
 154                         return -ENOMEM;
 155                 }
 156         }
 157
 158         if (config->microvolts)
 159                 drvdata->desc.n_voltages = 1;
 160
 161         drvdata->desc.fixed_uV = config->microvolts;
 162
 163         if (gpio_is_valid(config->gpio)) {
 164                 cfg.ena_gpio = config->gpio;
 165                 if (pdev->dev.of_node)
 166                         cfg.ena_gpio_initialized = true;
 167         }
 168         cfg.ena_gpio_invert = !config->enable_high;
 169         if (config->enabled_at_boot) {
 170                 if (config->enable_high)
 171                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 172                 else
 173                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 174         } else {
 175                 if (config->enable_high)
 176                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 177                 else
 178                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 179         }
 180         if (config->gpio_is_open_drain)
 181                 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
 182
 183         cfg.dev = &pdev->dev;
 184         cfg.init_data = config->init_data;
 185         cfg.driver_data = drvdata;
 186         cfg.of_node = pdev->dev.of_node;
 187
 188         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 189                                                &cfg);
 190         if (IS_ERR(drvdata->dev)) {
 191                 ret = PTR_ERR(drvdata->dev);
 192                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 193                 return ret;
 194         }
 195
 196         platform_set_drvdata(pdev, drvdata);
 197
 198         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 199                 drvdata->desc.fixed_uV);
 200
 201         return 0;
 202 }
 203
 204 #if defined(CONFIG_OF)
 205 static const struct of_device_id fixed_of_match[] = {
 206         { .compatible = "regulator-fixed", },
 207         {},
 208 };
 209 MODULE_DEVICE_TABLE(of, fixed_of_match);
 210 #endif
 211
 212 static struct platform_driver regulator_fixed_voltage_driver = {
 213         .probe          = reg_fixed_voltage_probe,
 214         .driver         = {
 215                 .name           = "reg-fixed-voltage",
 216                 .owner          = THIS_MODULE,
 217                 .of_match_table = of_match_ptr(fixed_of_match),
 218         },
 219 };
 220
 221 static int __init regulator_fixed_voltage_init(void)
 222 {
 223         return platform_driver_register(&regulator_fixed_voltage_driver);
 224 }
 225 subsys_initcall(regulator_fixed_voltage_init);
 226
 227 static void __exit regulator_fixed_voltage_exit(void)
 228 {
 229         platform_driver_unregister(&regulator_fixed_voltage_driver);
 230 }
 231 module_exit(regulator_fixed_voltage_exit);
 232
 233 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 234 MODULE_DESCRIPTION("Fixed voltage regulator");
 235 MODULE_LICENSE("GPL");
 236 MODULE_ALIAS("platform:reg-fixed-voltage");