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         /*
  83          * FIXME: we pulled active low/high and open drain handling into
  84          * gpiolib so it will be handled there. Delete this in the second
  85          * step when we also remove the custom inversion handling for all
  86          * legacy boardfiles.
  87          */
  88         config->enable_high = 1;
  89         config->gpio_is_open_drain = 0;
  90
  91         if (of_find_property(np, "vin-supply", NULL))
  92                 config->input_supply = "vin";
  93
  94         return config;
  95 }
  96
  97 static struct regulator_ops fixed_voltage_ops = {
  98 };
  99
 100 static int reg_fixed_voltage_probe(struct platform_device *pdev)
 101 {
 102         struct fixed_voltage_config *config;
 103         struct fixed_voltage_data *drvdata;
 104         struct regulator_config cfg = { };
 105         enum gpiod_flags gflags;
 106         int ret;
 107
 108         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 109                                GFP_KERNEL);
 110         if (!drvdata)
 111                 return -ENOMEM;
 112
 113         if (pdev->dev.of_node) {
 114                 config = of_get_fixed_voltage_config(&pdev->dev,
 115                                                      &drvdata->desc);
 116                 if (IS_ERR(config))
 117                         return PTR_ERR(config);
 118         } else {
 119                 config = dev_get_platdata(&pdev->dev);
 120         }
 121
 122         if (!config)
 123                 return -ENOMEM;
 124
 125         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 126                                           config->supply_name,
 127                                           GFP_KERNEL);
 128         if (drvdata->desc.name == NULL) {
 129                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 130                 return -ENOMEM;
 131         }
 132         drvdata->desc.type = REGULATOR_VOLTAGE;
 133         drvdata->desc.owner = THIS_MODULE;
 134         drvdata->desc.ops = &fixed_voltage_ops;
 135
 136         drvdata->desc.enable_time = config->startup_delay;
 137
 138         if (config->input_supply) {
 139                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 140                                             config->input_supply,
 141                                             GFP_KERNEL);
 142                 if (!drvdata->desc.supply_name) {
 143                         dev_err(&pdev->dev,
 144                                 "Failed to allocate input supply\n");
 145                         return -ENOMEM;
 146                 }
 147         }
 148
 149         if (config->microvolts)
 150                 drvdata->desc.n_voltages = 1;
 151
 152         drvdata->desc.fixed_uV = config->microvolts;
 153
 154         cfg.ena_gpio_invert = !config->enable_high;
 155         if (config->enabled_at_boot) {
 156                 if (config->enable_high)
 157                         gflags = GPIOD_OUT_HIGH;
 158                 else
 159                         gflags = GPIOD_OUT_LOW;
 160         } else {
 161                 if (config->enable_high)
 162                         gflags = GPIOD_OUT_LOW;
 163                 else
 164                         gflags = GPIOD_OUT_HIGH;
 165         }
 166         if (config->gpio_is_open_drain) {
 167                 if (gflags == GPIOD_OUT_HIGH)
 168                         gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
 169                 else
 170                         gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
 171         }
 172
 173         /*
 174          * Some fixed regulators share the enable line between two
 175          * regulators which makes it necessary to get a handle on the
 176          * same descriptor for two different consumers. This will get
 177          * the GPIO descriptor, but only the first call will initialize
 178          * it so any flags such as inversion or open drain will only
 179          * be set up by the first caller and assumed identical on the
 180          * next caller.
 181          *
 182          * FIXME: find a better way to deal with this.
 183          */
 184         gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 185
 186         cfg.ena_gpiod = devm_gpiod_get_optional(&pdev->dev, NULL, gflags);
 187         if (IS_ERR(cfg.ena_gpiod))
 188                 return PTR_ERR(cfg.ena_gpiod);
 189
 190         cfg.dev = &pdev->dev;
 191         cfg.init_data = config->init_data;
 192         cfg.driver_data = drvdata;
 193         cfg.of_node = pdev->dev.of_node;
 194
 195         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 196                                                &cfg);
 197         if (IS_ERR(drvdata->dev)) {
 198                 ret = PTR_ERR(drvdata->dev);
 199                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 200                 return ret;
 201         }
 202
 203         platform_set_drvdata(pdev, drvdata);
 204
 205         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 206                 drvdata->desc.fixed_uV);
 207
 208         return 0;
 209 }
 210
 211 #if defined(CONFIG_OF)
 212 static const struct of_device_id fixed_of_match[] = {
 213         { .compatible = "regulator-fixed", },
 214         {},
 215 };
 216 MODULE_DEVICE_TABLE(of, fixed_of_match);
 217 #endif
 218
 219 static struct platform_driver regulator_fixed_voltage_driver = {
 220         .probe          = reg_fixed_voltage_probe,
 221         .driver         = {
 222                 .name           = "reg-fixed-voltage",
 223                 .of_match_table = of_match_ptr(fixed_of_match),
 224         },
 225 };
 226
 227 static int __init regulator_fixed_voltage_init(void)
 228 {
 229         return platform_driver_register(&regulator_fixed_voltage_driver);
 230 }
 231 subsys_initcall(regulator_fixed_voltage_init);
 232
 233 static void __exit regulator_fixed_voltage_exit(void)
 234 {
 235         platform_driver_unregister(&regulator_fixed_voltage_driver);
 236 }
 237 module_exit(regulator_fixed_voltage_exit);
 238
 239 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 240 MODULE_DESCRIPTION("Fixed voltage regulator");
 241 MODULE_LICENSE("GPL");
 242 MODULE_ALIAS("platform:reg-fixed-voltage");