drivers/regulator/fixed.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * fixed.c
   4  *
   5  * Copyright 2008 Wolfson Microelectronics PLC.
   6  *
   7  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   8  *
   9  * Copyright (c) 2009 Nokia Corporation
  10  * Roger Quadros <ext-roger.quadros@nokia.com>
  11  *
  12  * This is useful for systems with mixed controllable and
  13  * non-controllable regulators, as well as for allowing testing on
  14  * systems with no controllable regulators.
  15  */
  16
  17 #include <linux/err.h>
  18 #include <linux/mutex.h>
  19 #include <linux/module.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/regulator/driver.h>
  22 #include <linux/regulator/fixed.h>
  23 #include <linux/gpio/consumer.h>
  24 #include <linux/slab.h>
  25 #include <linux/of.h>
  26 #include <linux/of_device.h>
  27 #include <linux/regulator/of_regulator.h>
  28 #include <linux/regulator/machine.h>
  29 #include <linux/clk.h>
  30
  31
  32 struct fixed_voltage_data {
  33         struct regulator_desc desc;
  34         struct regulator_dev *dev;
  35
  36         struct clk *enable_clock;
  37         unsigned int clk_enable_counter;
  38 };
  39
  40 struct fixed_dev_type {
  41         bool has_enable_clock;
  42 };
  43
  44 static int reg_clock_enable(struct regulator_dev *rdev)
  45 {
  46         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  47         int ret = 0;
  48
  49         ret = clk_prepare_enable(priv->enable_clock);
  50         if (ret)
  51                 return ret;
  52
  53         priv->clk_enable_counter++;
  54
  55         return ret;
  56 }
  57
  58 static int reg_clock_disable(struct regulator_dev *rdev)
  59 {
  60         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  61
  62         clk_disable_unprepare(priv->enable_clock);
  63         priv->clk_enable_counter--;
  64
  65         return 0;
  66 }
  67
  68 static int reg_clock_is_enabled(struct regulator_dev *rdev)
  69 {
  70         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  71
  72         return priv->clk_enable_counter > 0;
  73 }
  74
  75
  76 /**
  77  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
  78  * @dev: device requesting for fixed_voltage_config
  79  * @desc: regulator description
  80  *
  81  * Populates fixed_voltage_config structure by extracting data from device
  82  * tree node, returns a pointer to the populated structure of NULL if memory
  83  * alloc fails.
  84  */
  85 static struct fixed_voltage_config *
  86 of_get_fixed_voltage_config(struct device *dev,
  87                             const struct regulator_desc *desc)
  88 {
  89         struct fixed_voltage_config *config;
  90         struct device_node *np = dev->of_node;
  91         struct regulator_init_data *init_data;
  92
  93         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
  94                                                                  GFP_KERNEL);
  95         if (!config)
  96                 return ERR_PTR(-ENOMEM);
  97
  98         config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
  99         if (!config->init_data)
 100                 return ERR_PTR(-EINVAL);
 101
 102         init_data = config->init_data;
 103         init_data->constraints.apply_uV = 0;
 104
 105         config->supply_name = init_data->constraints.name;
 106         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
 107                 config->microvolts = init_data->constraints.min_uV;
 108         } else {
 109                 dev_err(dev,
 110                          "Fixed regulator specified with variable voltages\n");
 111                 return ERR_PTR(-EINVAL);
 112         }
 113
 114         if (init_data->constraints.boot_on)
 115                 config->enabled_at_boot = true;
 116
 117         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 118         of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
 119
 120         if (of_find_property(np, "vin-supply", NULL))
 121                 config->input_supply = "vin";
 122
 123         return config;
 124 }
 125
 126 static const struct regulator_ops fixed_voltage_ops = {
 127 };
 128
 129 static const struct regulator_ops fixed_voltage_clkenabled_ops = {
 130         .enable = reg_clock_enable,
 131         .disable = reg_clock_disable,
 132         .is_enabled = reg_clock_is_enabled,
 133 };
 134
 135 static int reg_fixed_voltage_probe(struct platform_device *pdev)
 136 {
 137         struct device *dev = &pdev->dev;
 138         struct fixed_voltage_config *config;
 139         struct fixed_voltage_data *drvdata;
 140         const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
 141         struct regulator_config cfg = { };
 142         enum gpiod_flags gflags;
 143         int ret;
 144
 145         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 146                                GFP_KERNEL);
 147         if (!drvdata)
 148                 return -ENOMEM;
 149
 150         if (pdev->dev.of_node) {
 151                 config = of_get_fixed_voltage_config(&pdev->dev,
 152                                                      &drvdata->desc);
 153                 if (IS_ERR(config))
 154                         return PTR_ERR(config);
 155         } else {
 156                 config = dev_get_platdata(&pdev->dev);
 157         }
 158
 159         if (!config)
 160                 return -ENOMEM;
 161
 162         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 163                                           config->supply_name,
 164                                           GFP_KERNEL);
 165         if (drvdata->desc.name == NULL) {
 166                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 167                 return -ENOMEM;
 168         }
 169         drvdata->desc.type = REGULATOR_VOLTAGE;
 170         drvdata->desc.owner = THIS_MODULE;
 171
 172         if (drvtype && drvtype->has_enable_clock) {
 173                 drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
 174
 175                 drvdata->enable_clock = devm_clk_get(dev, NULL);
 176                 if (IS_ERR(drvdata->enable_clock)) {
 177                         dev_err(dev, "Can't get enable-clock from devicetree\n");
 178                         return -ENOENT;
 179                 }
 180         } else {
 181                 drvdata->desc.ops = &fixed_voltage_ops;
 182         }
 183
 184         drvdata->desc.enable_time = config->startup_delay;
 185         drvdata->desc.off_on_delay = config->off_on_delay;
 186
 187         if (config->input_supply) {
 188                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 189                                             config->input_supply,
 190                                             GFP_KERNEL);
 191                 if (!drvdata->desc.supply_name) {
 192                         dev_err(&pdev->dev,
 193                                 "Failed to allocate input supply\n");
 194                         return -ENOMEM;
 195                 }
 196         }
 197
 198         if (config->microvolts)
 199                 drvdata->desc.n_voltages = 1;
 200
 201         drvdata->desc.fixed_uV = config->microvolts;
 202
 203         /*
 204          * The signal will be inverted by the GPIO core if flagged so in the
 205          * descriptor.
 206          */
 207         if (config->enabled_at_boot)
 208                 gflags = GPIOD_OUT_HIGH;
 209         else
 210                 gflags = GPIOD_OUT_LOW;
 211
 212         /*
 213          * Some fixed regulators share the enable line between two
 214          * regulators which makes it necessary to get a handle on the
 215          * same descriptor for two different consumers. This will get
 216          * the GPIO descriptor, but only the first call will initialize
 217          * it so any flags such as inversion or open drain will only
 218          * be set up by the first caller and assumed identical on the
 219          * next caller.
 220          *
 221          * FIXME: find a better way to deal with this.
 222          */
 223         gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 224
 225         /*
 226          * Do not use devm* here: the regulator core takes over the
 227          * lifecycle management of the GPIO descriptor.
 228          */
 229         cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
 230         if (IS_ERR(cfg.ena_gpiod))
 231                 return PTR_ERR(cfg.ena_gpiod);
 232
 233         cfg.dev = &pdev->dev;
 234         cfg.init_data = config->init_data;
 235         cfg.driver_data = drvdata;
 236         cfg.of_node = pdev->dev.of_node;
 237
 238         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 239                                                &cfg);
 240         if (IS_ERR(drvdata->dev)) {
 241                 ret = PTR_ERR(drvdata->dev);
 242                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 243                 return ret;
 244         }
 245
 246         platform_set_drvdata(pdev, drvdata);
 247
 248         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 249                 drvdata->desc.fixed_uV);
 250
 251         return 0;
 252 }
 253
 254 #if defined(CONFIG_OF)
 255 static const struct fixed_dev_type fixed_voltage_data = {
 256         .has_enable_clock = false,
 257 };
 258
 259 static const struct fixed_dev_type fixed_clkenable_data = {
 260         .has_enable_clock = true,
 261 };
 262
 263 static const struct of_device_id fixed_of_match[] = {
 264         {
 265                 .compatible = "regulator-fixed",
 266                 .data = &fixed_voltage_data,
 267         },
 268         {
 269                 .compatible = "regulator-fixed-clock",
 270                 .data = &fixed_clkenable_data,
 271         },
 272         {
 273         },
 274 };
 275 MODULE_DEVICE_TABLE(of, fixed_of_match);
 276 #endif
 277
 278 static struct platform_driver regulator_fixed_voltage_driver = {
 279         .probe          = reg_fixed_voltage_probe,
 280         .driver         = {
 281                 .name           = "reg-fixed-voltage",
 282                 .of_match_table = of_match_ptr(fixed_of_match),
 283         },
 284 };
 285
 286 static int __init regulator_fixed_voltage_init(void)
 287 {
 288         return platform_driver_register(&regulator_fixed_voltage_driver);
 289 }
 290 subsys_initcall(regulator_fixed_voltage_init);
 291
 292 static void __exit regulator_fixed_voltage_exit(void)
 293 {
 294         platform_driver_unregister(&regulator_fixed_voltage_driver);
 295 }
 296 module_exit(regulator_fixed_voltage_exit);
 297
 298 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 299 MODULE_DESCRIPTION("Fixed voltage regulator");
 300 MODULE_LICENSE("GPL");
 301 MODULE_ALIAS("platform:reg-fixed-voltage");