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/consumer.h>
  28 #include <linux/slab.h>
  29 #include <linux/of.h>
  30 #include <linux/regulator/of_regulator.h>
  31 #include <linux/regulator/machine.h>
  32
  33 struct fixed_voltage_data {
  34         struct regulator_desc desc;
  35         struct regulator_dev *dev;
  36 };
  37
  38
  39 /**
  40  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
  41  * @dev: device requesting for fixed_voltage_config
  42  * @desc: regulator description
  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                             const struct regulator_desc *desc)
  51 {
  52         struct fixed_voltage_config *config;
  53         struct device_node *np = dev->of_node;
  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, desc);
  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         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
  81
  82         if (of_find_property(np, "vin-supply", NULL))
  83                 config->input_supply = "vin";
  84
  85         return config;
  86 }
  87
  88 static struct regulator_ops fixed_voltage_ops = {
  89 };
  90
  91 static int reg_fixed_voltage_probe(struct platform_device *pdev)
  92 {
  93         struct fixed_voltage_config *config;
  94         struct fixed_voltage_data *drvdata;
  95         struct regulator_config cfg = { };
  96         enum gpiod_flags gflags;
  97         int ret;
  98
  99         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 100                                GFP_KERNEL);
 101         if (!drvdata)
 102                 return -ENOMEM;
 103
 104         if (pdev->dev.of_node) {
 105                 config = of_get_fixed_voltage_config(&pdev->dev,
 106                                                      &drvdata->desc);
 107                 if (IS_ERR(config))
 108                         return PTR_ERR(config);
 109         } else {
 110                 config = dev_get_platdata(&pdev->dev);
 111         }
 112
 113         if (!config)
 114                 return -ENOMEM;
 115
 116         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 117                                           config->supply_name,
 118                                           GFP_KERNEL);
 119         if (drvdata->desc.name == NULL) {
 120                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 121                 return -ENOMEM;
 122         }
 123         drvdata->desc.type = REGULATOR_VOLTAGE;
 124         drvdata->desc.owner = THIS_MODULE;
 125         drvdata->desc.ops = &fixed_voltage_ops;
 126
 127         drvdata->desc.enable_time = config->startup_delay;
 128
 129         if (config->input_supply) {
 130                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 131                                             config->input_supply,
 132                                             GFP_KERNEL);
 133                 if (!drvdata->desc.supply_name) {
 134                         dev_err(&pdev->dev,
 135                                 "Failed to allocate input supply\n");
 136                         return -ENOMEM;
 137                 }
 138         }
 139
 140         if (config->microvolts)
 141                 drvdata->desc.n_voltages = 1;
 142
 143         drvdata->desc.fixed_uV = config->microvolts;
 144
 145         /*
 146          * The signal will be inverted by the GPIO core if flagged so in the
 147          * decriptor.
 148          */
 149         if (config->enabled_at_boot)
 150                 gflags = GPIOD_OUT_HIGH;
 151         else
 152                 gflags = GPIOD_OUT_LOW;
 153
 154         /*
 155          * Some fixed regulators share the enable line between two
 156          * regulators which makes it necessary to get a handle on the
 157          * same descriptor for two different consumers. This will get
 158          * the GPIO descriptor, but only the first call will initialize
 159          * it so any flags such as inversion or open drain will only
 160          * be set up by the first caller and assumed identical on the
 161          * next caller.
 162          *
 163          * FIXME: find a better way to deal with this.
 164          */
 165         gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 166
 167         /*
 168          * Do not use devm* here: the regulator core takes over the
 169          * lifecycle management of the GPIO descriptor.
 170          */
 171         cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
 172         if (IS_ERR(cfg.ena_gpiod))
 173                 return PTR_ERR(cfg.ena_gpiod);
 174
 175         cfg.dev = &pdev->dev;
 176         cfg.init_data = config->init_data;
 177         cfg.driver_data = drvdata;
 178         cfg.of_node = pdev->dev.of_node;
 179
 180         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 181                                                &cfg);
 182         if (IS_ERR(drvdata->dev)) {
 183                 ret = PTR_ERR(drvdata->dev);
 184                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 185                 return ret;
 186         }
 187
 188         platform_set_drvdata(pdev, drvdata);
 189
 190         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 191                 drvdata->desc.fixed_uV);
 192
 193         return 0;
 194 }
 195
 196 #if defined(CONFIG_OF)
 197 static const struct of_device_id fixed_of_match[] = {
 198         { .compatible = "regulator-fixed", },
 199         {},
 200 };
 201 MODULE_DEVICE_TABLE(of, fixed_of_match);
 202 #endif
 203
 204 static struct platform_driver regulator_fixed_voltage_driver = {
 205         .probe          = reg_fixed_voltage_probe,
 206         .driver         = {
 207                 .name           = "reg-fixed-voltage",
 208                 .of_match_table = of_match_ptr(fixed_of_match),
 209         },
 210 };
 211
 212 static int __init regulator_fixed_voltage_init(void)
 213 {
 214         return platform_driver_register(&regulator_fixed_voltage_driver);
 215 }
 216 subsys_initcall(regulator_fixed_voltage_init);
 217
 218 static void __exit regulator_fixed_voltage_exit(void)
 219 {
 220         platform_driver_unregister(&regulator_fixed_voltage_driver);
 221 }
 222 module_exit(regulator_fixed_voltage_exit);
 223
 224 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 225 MODULE_DESCRIPTION("Fixed voltage regulator");
 226 MODULE_LICENSE("GPL");
 227 MODULE_ALIAS("platform:reg-fixed-voltage");