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         const __be32 *delay;
  54         struct regulator_init_data *init_data;
  55
  56         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
  57                                                                  GFP_KERNEL);
  58         if (!config)
  59                 return ERR_PTR(-ENOMEM);
  60
  61         config->init_data = of_get_regulator_init_data(dev, dev->of_node);
  62         if (!config->init_data)
  63                 return ERR_PTR(-EINVAL);
  64
  65         init_data = config->init_data;
  66         init_data->constraints.apply_uV = 0;
  67
  68         config->supply_name = init_data->constraints.name;
  69         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
  70                 config->microvolts = init_data->constraints.min_uV;
  71         } else {
  72                 dev_err(dev,
  73                          "Fixed regulator specified with variable voltages\n");
  74                 return ERR_PTR(-EINVAL);
  75         }
  76
  77         if (init_data->constraints.boot_on)
  78                 config->enabled_at_boot = true;
  79
  80         config->gpio = of_get_named_gpio(np, "gpio", 0);
  81         /*
  82          * of_get_named_gpio() currently returns ENODEV rather than
  83          * EPROBE_DEFER. This code attempts to be compatible with both
  84          * for now; the ENODEV check can be removed once the API is fixed.
  85          * of_get_named_gpio() doesn't differentiate between a missing
  86          * property (which would be fine here, since the GPIO is optional)
  87          * and some other error. Patches have been posted for both issues.
  88          * Once they are check in, we should replace this with:
  89          * if (config->gpio < 0 && config->gpio != -ENOENT)
  90          */
  91         if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER))
  92                 return ERR_PTR(-EPROBE_DEFER);
  93
  94         delay = of_get_property(np, "startup-delay-us", NULL);
  95         if (delay)
  96                 config->startup_delay = be32_to_cpu(*delay);
  97
  98         if (of_find_property(np, "enable-active-high", NULL))
  99                 config->enable_high = true;
 100
 101         if (of_find_property(np, "gpio-open-drain", NULL))
 102                 config->gpio_is_open_drain = true;
 103
 104         if (of_find_property(np, "vin-supply", NULL))
 105                 config->input_supply = "vin";
 106
 107         return config;
 108 }
 109
 110 static struct regulator_ops fixed_voltage_ops = {
 111 };
 112
 113 static int reg_fixed_voltage_probe(struct platform_device *pdev)
 114 {
 115         struct fixed_voltage_config *config;
 116         struct fixed_voltage_data *drvdata;
 117         struct regulator_config cfg = { };
 118         int ret;
 119
 120         if (pdev->dev.of_node) {
 121                 config = of_get_fixed_voltage_config(&pdev->dev);
 122                 if (IS_ERR(config))
 123                         return PTR_ERR(config);
 124         } else {
 125                 config = dev_get_platdata(&pdev->dev);
 126         }
 127
 128         if (!config)
 129                 return -ENOMEM;
 130
 131         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 132                                GFP_KERNEL);
 133         if (drvdata == NULL) {
 134                 dev_err(&pdev->dev, "Failed to allocate device data\n");
 135                 ret = -ENOMEM;
 136                 goto err;
 137         }
 138
 139         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 140         if (drvdata->desc.name == NULL) {
 141                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 142                 ret = -ENOMEM;
 143                 goto err;
 144         }
 145         drvdata->desc.type = REGULATOR_VOLTAGE;
 146         drvdata->desc.owner = THIS_MODULE;
 147         drvdata->desc.ops = &fixed_voltage_ops;
 148
 149         drvdata->desc.enable_time = config->startup_delay;
 150
 151         if (config->input_supply) {
 152                 drvdata->desc.supply_name = kstrdup(config->input_supply,
 153                                                         GFP_KERNEL);
 154                 if (!drvdata->desc.supply_name) {
 155                         dev_err(&pdev->dev,
 156                                 "Failed to allocate input supply\n");
 157                         ret = -ENOMEM;
 158                         goto err_name;
 159                 }
 160         }
 161
 162         if (config->microvolts)
 163                 drvdata->desc.n_voltages = 1;
 164
 165         drvdata->desc.fixed_uV = config->microvolts;
 166
 167         if (config->gpio >= 0)
 168                 cfg.ena_gpio = config->gpio;
 169         cfg.ena_gpio_invert = !config->enable_high;
 170         if (config->enabled_at_boot) {
 171                 if (config->enable_high)
 172                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 173                 else
 174                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 175         } else {
 176                 if (config->enable_high)
 177                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 178                 else
 179                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 180         }
 181         if (config->gpio_is_open_drain)
 182                 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
 183
 184         cfg.dev = &pdev->dev;
 185         cfg.init_data = config->init_data;
 186         cfg.driver_data = drvdata;
 187         cfg.of_node = pdev->dev.of_node;
 188
 189         drvdata->dev = regulator_register(&drvdata->desc, &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                 goto err_input;
 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 err_input:
 204         kfree(drvdata->desc.supply_name);
 205 err_name:
 206         kfree(drvdata->desc.name);
 207 err:
 208         return ret;
 209 }
 210
 211 static int reg_fixed_voltage_remove(struct platform_device *pdev)
 212 {
 213         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
 214
 215         regulator_unregister(drvdata->dev);
 216         kfree(drvdata->desc.supply_name);
 217         kfree(drvdata->desc.name);
 218
 219         return 0;
 220 }
 221
 222 #if defined(CONFIG_OF)
 223 static const struct of_device_id fixed_of_match[] = {
 224         { .compatible = "regulator-fixed", },
 225         {},
 226 };
 227 MODULE_DEVICE_TABLE(of, fixed_of_match);
 228 #endif
 229
 230 static struct platform_driver regulator_fixed_voltage_driver = {
 231         .probe          = reg_fixed_voltage_probe,
 232         .remove         = reg_fixed_voltage_remove,
 233         .driver         = {
 234                 .name           = "reg-fixed-voltage",
 235                 .owner          = THIS_MODULE,
 236                 .of_match_table = of_match_ptr(fixed_of_match),
 237         },
 238 };
 239
 240 static int __init regulator_fixed_voltage_init(void)
 241 {
 242         return platform_driver_register(&regulator_fixed_voltage_driver);
 243 }
 244 subsys_initcall(regulator_fixed_voltage_init);
 245
 246 static void __exit regulator_fixed_voltage_exit(void)
 247 {
 248         platform_driver_unregister(&regulator_fixed_voltage_driver);
 249 }
 250 module_exit(regulator_fixed_voltage_exit);
 251
 252 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 253 MODULE_DESCRIPTION("Fixed voltage regulator");
 254 MODULE_LICENSE("GPL");
 255 MODULE_ALIAS("platform:reg-fixed-voltage");