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)
 134                 return -ENOMEM;
 135
 136         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 137                                           config->supply_name,
 138                                           GFP_KERNEL);
 139         if (drvdata->desc.name == NULL) {
 140                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 141                 return -ENOMEM;
 142         }
 143         drvdata->desc.type = REGULATOR_VOLTAGE;
 144         drvdata->desc.owner = THIS_MODULE;
 145         drvdata->desc.ops = &fixed_voltage_ops;
 146
 147         drvdata->desc.enable_time = config->startup_delay;
 148
 149         if (config->input_supply) {
 150                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 151                                             config->input_supply,
 152                                             GFP_KERNEL);
 153                 if (!drvdata->desc.supply_name) {
 154                         dev_err(&pdev->dev,
 155                                 "Failed to allocate input supply\n");
 156                         return -ENOMEM;
 157                 }
 158         }
 159
 160         if (config->microvolts)
 161                 drvdata->desc.n_voltages = 1;
 162
 163         drvdata->desc.fixed_uV = config->microvolts;
 164
 165         if (config->gpio >= 0)
 166                 cfg.ena_gpio = config->gpio;
 167         cfg.ena_gpio_invert = !config->enable_high;
 168         if (config->enabled_at_boot) {
 169                 if (config->enable_high)
 170                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 171                 else
 172                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 173         } else {
 174                 if (config->enable_high)
 175                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 176                 else
 177                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 178         }
 179         if (config->gpio_is_open_drain)
 180                 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
 181
 182         cfg.dev = &pdev->dev;
 183         cfg.init_data = config->init_data;
 184         cfg.driver_data = drvdata;
 185         cfg.of_node = pdev->dev.of_node;
 186
 187         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 188                                                &cfg);
 189         if (IS_ERR(drvdata->dev)) {
 190                 ret = PTR_ERR(drvdata->dev);
 191                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 192                 return ret;
 193         }
 194
 195         platform_set_drvdata(pdev, drvdata);
 196
 197         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 198                 drvdata->desc.fixed_uV);
 199
 200         return 0;
 201 }
 202
 203 #if defined(CONFIG_OF)
 204 static const struct of_device_id fixed_of_match[] = {
 205         { .compatible = "regulator-fixed", },
 206         {},
 207 };
 208 MODULE_DEVICE_TABLE(of, fixed_of_match);
 209 #endif
 210
 211 static struct platform_driver regulator_fixed_voltage_driver = {
 212         .probe          = reg_fixed_voltage_probe,
 213         .driver         = {
 214                 .name           = "reg-fixed-voltage",
 215                 .owner          = THIS_MODULE,
 216                 .of_match_table = of_match_ptr(fixed_of_match),
 217         },
 218 };
 219
 220 static int __init regulator_fixed_voltage_init(void)
 221 {
 222         return platform_driver_register(&regulator_fixed_voltage_driver);
 223 }
 224 subsys_initcall(regulator_fixed_voltage_init);
 225
 226 static void __exit regulator_fixed_voltage_exit(void)
 227 {
 228         platform_driver_unregister(&regulator_fixed_voltage_driver);
 229 }
 230 module_exit(regulator_fixed_voltage_exit);
 231
 232 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 233 MODULE_DESCRIPTION("Fixed voltage regulator");
 234 MODULE_LICENSE("GPL");
 235 MODULE_ALIAS("platform:reg-fixed-voltage");