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