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/pm_domain.h>
  22 #include <linux/pm_opp.h>
  23 #include <linux/regulator/driver.h>
  24 #include <linux/regulator/fixed.h>
  25 #include <linux/gpio/consumer.h>
  26 #include <linux/slab.h>
  27 #include <linux/of.h>
  28 #include <linux/of_device.h>
  29 #include <linux/regulator/of_regulator.h>
  30 #include <linux/regulator/machine.h>
  31 #include <linux/clk.h>
  32
  33
  34 struct fixed_voltage_data {
  35         struct regulator_desc desc;
  36         struct regulator_dev *dev;
  37
  38         struct clk *enable_clock;
  39         unsigned int enable_counter;
  40         int performance_state;
  41 };
  42
  43 struct fixed_dev_type {
  44         bool has_enable_clock;
  45         bool has_performance_state;
  46 };
  47
  48 static int reg_clock_enable(struct regulator_dev *rdev)
  49 {
  50         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  51         int ret = 0;
  52
  53         ret = clk_prepare_enable(priv->enable_clock);
  54         if (ret)
  55                 return ret;
  56
  57         priv->enable_counter++;
  58
  59         return ret;
  60 }
  61
  62 static int reg_clock_disable(struct regulator_dev *rdev)
  63 {
  64         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  65
  66         clk_disable_unprepare(priv->enable_clock);
  67         priv->enable_counter--;
  68
  69         return 0;
  70 }
  71
  72 static int reg_domain_enable(struct regulator_dev *rdev)
  73 {
  74         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  75         struct device *dev = rdev->dev.parent;
  76         int ret;
  77
  78         ret = dev_pm_genpd_set_performance_state(dev, priv->performance_state);
  79         if (ret)
  80                 return ret;
  81
  82         priv->enable_counter++;
  83
  84         return ret;
  85 }
  86
  87 static int reg_domain_disable(struct regulator_dev *rdev)
  88 {
  89         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  90         struct device *dev = rdev->dev.parent;
  91         int ret;
  92
  93         ret = dev_pm_genpd_set_performance_state(dev, 0);
  94         if (ret)
  95                 return ret;
  96
  97         priv->enable_counter--;
  98
  99         return 0;
 100 }
 101
 102 static int reg_is_enabled(struct regulator_dev *rdev)
 103 {
 104         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
 105
 106         return priv->enable_counter > 0;
 107 }
 108
 109
 110 /**
 111  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
 112  * @dev: device requesting for fixed_voltage_config
 113  * @desc: regulator description
 114  *
 115  * Populates fixed_voltage_config structure by extracting data from device
 116  * tree node, returns a pointer to the populated structure of NULL if memory
 117  * alloc fails.
 118  */
 119 static struct fixed_voltage_config *
 120 of_get_fixed_voltage_config(struct device *dev,
 121                             const struct regulator_desc *desc)
 122 {
 123         struct fixed_voltage_config *config;
 124         struct device_node *np = dev->of_node;
 125         struct regulator_init_data *init_data;
 126
 127         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
 128                                                                  GFP_KERNEL);
 129         if (!config)
 130                 return ERR_PTR(-ENOMEM);
 131
 132         config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
 133         if (!config->init_data)
 134                 return ERR_PTR(-EINVAL);
 135
 136         init_data = config->init_data;
 137         init_data->constraints.apply_uV = 0;
 138
 139         config->supply_name = init_data->constraints.name;
 140         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
 141                 config->microvolts = init_data->constraints.min_uV;
 142         } else {
 143                 dev_err(dev,
 144                          "Fixed regulator specified with variable voltages\n");
 145                 return ERR_PTR(-EINVAL);
 146         }
 147
 148         if (init_data->constraints.boot_on)
 149                 config->enabled_at_boot = true;
 150
 151         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 152         of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
 153
 154         if (of_find_property(np, "vin-supply", NULL))
 155                 config->input_supply = "vin";
 156
 157         return config;
 158 }
 159
 160 static const struct regulator_ops fixed_voltage_ops = {
 161 };
 162
 163 static const struct regulator_ops fixed_voltage_clkenabled_ops = {
 164         .enable = reg_clock_enable,
 165         .disable = reg_clock_disable,
 166         .is_enabled = reg_is_enabled,
 167 };
 168
 169 static const struct regulator_ops fixed_voltage_domain_ops = {
 170         .enable = reg_domain_enable,
 171         .disable = reg_domain_disable,
 172         .is_enabled = reg_is_enabled,
 173 };
 174
 175 static int reg_fixed_voltage_probe(struct platform_device *pdev)
 176 {
 177         struct device *dev = &pdev->dev;
 178         struct fixed_voltage_config *config;
 179         struct fixed_voltage_data *drvdata;
 180         const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
 181         struct regulator_config cfg = { };
 182         enum gpiod_flags gflags;
 183         int ret;
 184
 185         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 186                                GFP_KERNEL);
 187         if (!drvdata)
 188                 return -ENOMEM;
 189
 190         if (pdev->dev.of_node) {
 191                 config = of_get_fixed_voltage_config(&pdev->dev,
 192                                                      &drvdata->desc);
 193                 if (IS_ERR(config))
 194                         return PTR_ERR(config);
 195         } else {
 196                 config = dev_get_platdata(&pdev->dev);
 197         }
 198
 199         if (!config)
 200                 return -ENOMEM;
 201
 202         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 203                                           config->supply_name,
 204                                           GFP_KERNEL);
 205         if (drvdata->desc.name == NULL) {
 206                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 207                 return -ENOMEM;
 208         }
 209         drvdata->desc.type = REGULATOR_VOLTAGE;
 210         drvdata->desc.owner = THIS_MODULE;
 211
 212         if (drvtype && drvtype->has_enable_clock) {
 213                 drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
 214
 215                 drvdata->enable_clock = devm_clk_get(dev, NULL);
 216                 if (IS_ERR(drvdata->enable_clock)) {
 217                         dev_err(dev, "Can't get enable-clock from devicetree\n");
 218                         return -ENOENT;
 219                 }
 220         } else if (drvtype && drvtype->has_performance_state) {
 221                 drvdata->desc.ops = &fixed_voltage_domain_ops;
 222
 223                 drvdata->performance_state = of_get_required_opp_performance_state(dev->of_node, 0);
 224                 if (drvdata->performance_state < 0) {
 225                         dev_err(dev, "Can't get performance state from devicetree\n");
 226                         return drvdata->performance_state;
 227                 }
 228         } else {
 229                 drvdata->desc.ops = &fixed_voltage_ops;
 230         }
 231
 232         drvdata->desc.enable_time = config->startup_delay;
 233         drvdata->desc.off_on_delay = config->off_on_delay;
 234
 235         if (config->input_supply) {
 236                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 237                                             config->input_supply,
 238                                             GFP_KERNEL);
 239                 if (!drvdata->desc.supply_name)
 240                         return -ENOMEM;
 241         }
 242
 243         if (config->microvolts)
 244                 drvdata->desc.n_voltages = 1;
 245
 246         drvdata->desc.fixed_uV = config->microvolts;
 247
 248         /*
 249          * The signal will be inverted by the GPIO core if flagged so in the
 250          * descriptor.
 251          */
 252         if (config->enabled_at_boot)
 253                 gflags = GPIOD_OUT_HIGH;
 254         else
 255                 gflags = GPIOD_OUT_LOW;
 256
 257         /*
 258          * Some fixed regulators share the enable line between two
 259          * regulators which makes it necessary to get a handle on the
 260          * same descriptor for two different consumers. This will get
 261          * the GPIO descriptor, but only the first call will initialize
 262          * it so any flags such as inversion or open drain will only
 263          * be set up by the first caller and assumed identical on the
 264          * next caller.
 265          *
 266          * FIXME: find a better way to deal with this.
 267          */
 268         gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 269
 270         /*
 271          * Do not use devm* here: the regulator core takes over the
 272          * lifecycle management of the GPIO descriptor.
 273          */
 274         cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
 275         if (IS_ERR(cfg.ena_gpiod))
 276                 return dev_err_probe(&pdev->dev, PTR_ERR(cfg.ena_gpiod),
 277                                      "can't get GPIO\n");
 278
 279         cfg.dev = &pdev->dev;
 280         cfg.init_data = config->init_data;
 281         cfg.driver_data = drvdata;
 282         cfg.of_node = pdev->dev.of_node;
 283
 284         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 285                                                &cfg);
 286         if (IS_ERR(drvdata->dev)) {
 287                 ret = dev_err_probe(&pdev->dev, PTR_ERR(drvdata->dev),
 288                                     "Failed to register regulator: %ld\n",
 289                                     PTR_ERR(drvdata->dev));
 290                 return ret;
 291         }
 292
 293         platform_set_drvdata(pdev, drvdata);
 294
 295         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 296                 drvdata->desc.fixed_uV);
 297
 298         return 0;
 299 }
 300
 301 #if defined(CONFIG_OF)
 302 static const struct fixed_dev_type fixed_voltage_data = {
 303         .has_enable_clock = false,
 304 };
 305
 306 static const struct fixed_dev_type fixed_clkenable_data = {
 307         .has_enable_clock = true,
 308 };
 309
 310 static const struct fixed_dev_type fixed_domain_data = {
 311         .has_performance_state = true,
 312 };
 313
 314 static const struct of_device_id fixed_of_match[] = {
 315         {
 316                 .compatible = "regulator-fixed",
 317                 .data = &fixed_voltage_data,
 318         },
 319         {
 320                 .compatible = "regulator-fixed-clock",
 321                 .data = &fixed_clkenable_data,
 322         },
 323         {
 324                 .compatible = "regulator-fixed-domain",
 325                 .data = &fixed_domain_data,
 326         },
 327         {
 328         },
 329 };
 330 MODULE_DEVICE_TABLE(of, fixed_of_match);
 331 #endif
 332
 333 static struct platform_driver regulator_fixed_voltage_driver = {
 334         .probe          = reg_fixed_voltage_probe,
 335         .driver         = {
 336                 .name           = "reg-fixed-voltage",
 337                 .of_match_table = of_match_ptr(fixed_of_match),
 338         },
 339 };
 340
 341 static int __init regulator_fixed_voltage_init(void)
 342 {
 343         return platform_driver_register(&regulator_fixed_voltage_driver);
 344 }
 345 subsys_initcall(regulator_fixed_voltage_init);
 346
 347 static void __exit regulator_fixed_voltage_exit(void)
 348 {
 349         platform_driver_unregister(&regulator_fixed_voltage_driver);
 350 }
 351 module_exit(regulator_fixed_voltage_exit);
 352
 353 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 354 MODULE_DESCRIPTION("Fixed voltage regulator");
 355 MODULE_LICENSE("GPL");
 356 MODULE_ALIAS("platform:reg-fixed-voltage");