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 #include <linux/acpi.h>
  34 #include <linux/property.h>
  35 #include <linux/gpio/consumer.h>
  36
  37 struct fixed_voltage_data {
  38         struct regulator_desc desc;
  39         struct regulator_dev *dev;
  40 };
  41
  42
  43 /**
  44  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
  45  * @dev: device requesting for fixed_voltage_config
  46  * @desc: regulator description
  47  *
  48  * Populates fixed_voltage_config structure by extracting data from device
  49  * tree node, returns a pointer to the populated structure of NULL if memory
  50  * alloc fails.
  51  */
  52 static struct fixed_voltage_config *
  53 of_get_fixed_voltage_config(struct device *dev,
  54                             const struct regulator_desc *desc)
  55 {
  56         struct fixed_voltage_config *config;
  57         struct device_node *np = dev->of_node;
  58         struct regulator_init_data *init_data;
  59
  60         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
  61                                                                  GFP_KERNEL);
  62         if (!config)
  63                 return ERR_PTR(-ENOMEM);
  64
  65         config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
  66         if (!config->init_data)
  67                 return ERR_PTR(-EINVAL);
  68
  69         init_data = config->init_data;
  70         init_data->constraints.apply_uV = 0;
  71
  72         config->supply_name = init_data->constraints.name;
  73         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
  74                 config->microvolts = init_data->constraints.min_uV;
  75         } else {
  76                 dev_err(dev,
  77                          "Fixed regulator specified with variable voltages\n");
  78                 return ERR_PTR(-EINVAL);
  79         }
  80
  81         if (init_data->constraints.boot_on)
  82                 config->enabled_at_boot = true;
  83
  84         config->gpio = of_get_named_gpio(np, "gpio", 0);
  85         if ((config->gpio < 0) && (config->gpio != -ENOENT))
  86                 return ERR_PTR(config->gpio);
  87
  88         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
  89
  90         config->enable_high = of_property_read_bool(np, "enable-active-high");
  91         config->gpio_is_open_drain = of_property_read_bool(np,
  92                                                            "gpio-open-drain");
  93
  94         if (of_find_property(np, "vin-supply", NULL))
  95                 config->input_supply = "vin";
  96
  97         return config;
  98 }
  99
 100 /**
 101  * acpi_get_fixed_voltage_config - extract fixed_voltage_config structure info
 102  * @dev: device requesting for fixed_voltage_config
 103  * @desc: regulator description
 104  *
 105  * Populates fixed_voltage_config structure by extracting data through ACPI
 106  * interface, returns a pointer to the populated structure of NULL if memory
 107  * alloc fails.
 108  */
 109 static struct fixed_voltage_config *
 110 acpi_get_fixed_voltage_config(struct device *dev,
 111                               const struct regulator_desc *desc)
 112 {
 113         struct fixed_voltage_config *config;
 114         const char *supply_name;
 115         struct gpio_desc *gpiod;
 116         int ret;
 117
 118         config = devm_kzalloc(dev, sizeof(*config), GFP_KERNEL);
 119         if (!config)
 120                 return ERR_PTR(-ENOMEM);
 121
 122         ret = device_property_read_string(dev, "supply-name", &supply_name);
 123         if (!ret)
 124                 config->supply_name = supply_name;
 125
 126         gpiod = gpiod_get(dev, "gpio", GPIOD_ASIS);
 127         if (IS_ERR(gpiod))
 128                 return ERR_PTR(-ENODEV);
 129
 130         config->gpio = desc_to_gpio(gpiod);
 131         config->enable_high = device_property_read_bool(dev,
 132                                                         "enable-active-high");
 133         gpiod_put(gpiod);
 134
 135         return config;
 136 }
 137
 138 static struct regulator_ops fixed_voltage_ops = {
 139 };
 140
 141 static int reg_fixed_voltage_probe(struct platform_device *pdev)
 142 {
 143         struct fixed_voltage_config *config;
 144         struct fixed_voltage_data *drvdata;
 145         struct regulator_config cfg = { };
 146         int ret;
 147
 148         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 149                                GFP_KERNEL);
 150         if (!drvdata)
 151                 return -ENOMEM;
 152
 153         if (pdev->dev.of_node) {
 154                 config = of_get_fixed_voltage_config(&pdev->dev,
 155                                                      &drvdata->desc);
 156                 if (IS_ERR(config))
 157                         return PTR_ERR(config);
 158         } else if (ACPI_HANDLE(&pdev->dev)) {
 159                 config = acpi_get_fixed_voltage_config(&pdev->dev,
 160                                                        &drvdata->desc);
 161                 if (IS_ERR(config))
 162                         return PTR_ERR(config);
 163         } else {
 164                 config = dev_get_platdata(&pdev->dev);
 165         }
 166
 167         if (!config)
 168                 return -ENOMEM;
 169
 170         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 171                                           config->supply_name,
 172                                           GFP_KERNEL);
 173         if (drvdata->desc.name == NULL) {
 174                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 175                 return -ENOMEM;
 176         }
 177         drvdata->desc.type = REGULATOR_VOLTAGE;
 178         drvdata->desc.owner = THIS_MODULE;
 179         drvdata->desc.ops = &fixed_voltage_ops;
 180
 181         drvdata->desc.enable_time = config->startup_delay;
 182
 183         if (config->input_supply) {
 184                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 185                                             config->input_supply,
 186                                             GFP_KERNEL);
 187                 if (!drvdata->desc.supply_name) {
 188                         dev_err(&pdev->dev,
 189                                 "Failed to allocate input supply\n");
 190                         return -ENOMEM;
 191                 }
 192         }
 193
 194         if (config->microvolts)
 195                 drvdata->desc.n_voltages = 1;
 196
 197         drvdata->desc.fixed_uV = config->microvolts;
 198
 199         if (gpio_is_valid(config->gpio)) {
 200                 cfg.ena_gpio = config->gpio;
 201                 if (pdev->dev.of_node)
 202                         cfg.ena_gpio_initialized = true;
 203         }
 204         cfg.ena_gpio_invert = !config->enable_high;
 205         if (config->enabled_at_boot) {
 206                 if (config->enable_high)
 207                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 208                 else
 209                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 210         } else {
 211                 if (config->enable_high)
 212                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 213                 else
 214                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 215         }
 216         if (config->gpio_is_open_drain)
 217                 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
 218
 219         cfg.dev = &pdev->dev;
 220         cfg.init_data = config->init_data;
 221         cfg.driver_data = drvdata;
 222         cfg.of_node = pdev->dev.of_node;
 223
 224         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 225                                                &cfg);
 226         if (IS_ERR(drvdata->dev)) {
 227                 ret = PTR_ERR(drvdata->dev);
 228                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 229                 return ret;
 230         }
 231
 232         platform_set_drvdata(pdev, drvdata);
 233
 234         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 235                 drvdata->desc.fixed_uV);
 236
 237         return 0;
 238 }
 239
 240 #if defined(CONFIG_OF)
 241 static const struct of_device_id fixed_of_match[] = {
 242         { .compatible = "regulator-fixed", },
 243         {},
 244 };
 245 MODULE_DEVICE_TABLE(of, fixed_of_match);
 246 #endif
 247
 248 static struct platform_driver regulator_fixed_voltage_driver = {
 249         .probe          = reg_fixed_voltage_probe,
 250         .driver         = {
 251                 .name           = "reg-fixed-voltage",
 252                 .of_match_table = of_match_ptr(fixed_of_match),
 253         },
 254 };
 255
 256 static int __init regulator_fixed_voltage_init(void)
 257 {
 258         return platform_driver_register(&regulator_fixed_voltage_driver);
 259 }
 260 subsys_initcall(regulator_fixed_voltage_init);
 261
 262 static void __exit regulator_fixed_voltage_exit(void)
 263 {
 264         platform_driver_unregister(&regulator_fixed_voltage_driver);
 265 }
 266 module_exit(regulator_fixed_voltage_exit);
 267
 268 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 269 MODULE_DESCRIPTION("Fixed voltage regulator");
 270 MODULE_LICENSE("GPL");
 271 MODULE_ALIAS("platform:reg-fixed-voltage");