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/reboot.h>
  24 #include <linux/regulator/driver.h>
  25 #include <linux/regulator/fixed.h>
  26 #include <linux/gpio/consumer.h>
  27 #include <linux/slab.h>
  28 #include <linux/of.h>
  29 #include <linux/regulator/of_regulator.h>
  30 #include <linux/regulator/machine.h>
  31 #include <linux/clk.h>
  32
  33 /* Default time in millisecond to wait for emergency shutdown */
  34 #define FV_DEF_EMERG_SHUTDWN_TMO        10
  35
  36 struct fixed_voltage_data {
  37         struct regulator_desc desc;
  38         struct regulator_dev *dev;
  39
  40         struct clk *enable_clock;
  41         unsigned int enable_counter;
  42         int performance_state;
  43 };
  44
  45 struct fixed_dev_type {
  46         bool has_enable_clock;
  47         bool has_performance_state;
  48 };
  49
  50 static int reg_clock_enable(struct regulator_dev *rdev)
  51 {
  52         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  53         int ret = 0;
  54
  55         ret = clk_prepare_enable(priv->enable_clock);
  56         if (ret)
  57                 return ret;
  58
  59         priv->enable_counter++;
  60
  61         return ret;
  62 }
  63
  64 static int reg_clock_disable(struct regulator_dev *rdev)
  65 {
  66         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  67
  68         clk_disable_unprepare(priv->enable_clock);
  69         priv->enable_counter--;
  70
  71         return 0;
  72 }
  73
  74 static int reg_domain_enable(struct regulator_dev *rdev)
  75 {
  76         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  77         struct device *dev = rdev->dev.parent;
  78         int ret;
  79
  80         ret = dev_pm_genpd_set_performance_state(dev, priv->performance_state);
  81         if (ret)
  82                 return ret;
  83
  84         priv->enable_counter++;
  85
  86         return ret;
  87 }
  88
  89 static int reg_domain_disable(struct regulator_dev *rdev)
  90 {
  91         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
  92         struct device *dev = rdev->dev.parent;
  93         int ret;
  94
  95         ret = dev_pm_genpd_set_performance_state(dev, 0);
  96         if (ret)
  97                 return ret;
  98
  99         priv->enable_counter--;
 100
 101         return 0;
 102 }
 103
 104 static int reg_is_enabled(struct regulator_dev *rdev)
 105 {
 106         struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
 107
 108         return priv->enable_counter > 0;
 109 }
 110
 111 static irqreturn_t reg_fixed_under_voltage_irq_handler(int irq, void *data)
 112 {
 113         struct fixed_voltage_data *priv = data;
 114         struct regulator_dev *rdev = priv->dev;
 115
 116         regulator_notifier_call_chain(rdev, REGULATOR_EVENT_UNDER_VOLTAGE,
 117                                       NULL);
 118
 119         return IRQ_HANDLED;
 120 }
 121
 122 /**
 123  * reg_fixed_get_irqs - Get and register the optional IRQ for fixed voltage
 124  *                      regulator.
 125  * @dev: Pointer to the device structure.
 126  * @priv: Pointer to fixed_voltage_data structure containing private data.
 127  *
 128  * This function tries to get the IRQ from the device firmware node.
 129  * If it's an optional IRQ and not found, it returns 0.
 130  * Otherwise, it attempts to request the threaded IRQ.
 131  *
 132  * Return: 0 on success, or a negative error number on failure.
 133  */
 134 static int reg_fixed_get_irqs(struct device *dev,
 135                               struct fixed_voltage_data *priv)
 136 {
 137         int ret;
 138
 139         ret = fwnode_irq_get(dev_fwnode(dev), 0);
 140         /* This is optional IRQ. If not found we will get -EINVAL */
 141         if (ret == -EINVAL)
 142                 return 0;
 143         if (ret < 0)
 144                 return dev_err_probe(dev, ret, "Failed to get IRQ\n");
 145
 146         ret = devm_request_threaded_irq(dev, ret, NULL,
 147                                         reg_fixed_under_voltage_irq_handler,
 148                                         IRQF_ONESHOT, "under-voltage", priv);
 149         if (ret)
 150                 return dev_err_probe(dev, ret, "Failed to request IRQ\n");
 151
 152         return 0;
 153 }
 154
 155 /**
 156  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
 157  * @dev: device requesting for fixed_voltage_config
 158  * @desc: regulator description
 159  *
 160  * Populates fixed_voltage_config structure by extracting data from device
 161  * tree node.
 162  *
 163  * Return: Pointer to a populated &struct fixed_voltage_config or %NULL if
 164  *         memory allocation fails.
 165  */
 166 static struct fixed_voltage_config *
 167 of_get_fixed_voltage_config(struct device *dev,
 168                             const struct regulator_desc *desc)
 169 {
 170         struct fixed_voltage_config *config;
 171         struct device_node *np = dev->of_node;
 172         struct regulator_init_data *init_data;
 173
 174         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
 175                                                                  GFP_KERNEL);
 176         if (!config)
 177                 return ERR_PTR(-ENOMEM);
 178
 179         config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
 180         if (!config->init_data)
 181                 return ERR_PTR(-EINVAL);
 182
 183         init_data = config->init_data;
 184         init_data->constraints.apply_uV = 0;
 185
 186         config->supply_name = init_data->constraints.name;
 187         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
 188                 config->microvolts = init_data->constraints.min_uV;
 189         } else {
 190                 dev_err(dev,
 191                          "Fixed regulator specified with variable voltages\n");
 192                 return ERR_PTR(-EINVAL);
 193         }
 194
 195         if (init_data->constraints.boot_on)
 196                 config->enabled_at_boot = true;
 197
 198         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 199         of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
 200
 201         if (of_property_present(np, "vin-supply"))
 202                 config->input_supply = "vin";
 203
 204         return config;
 205 }
 206
 207 static const struct regulator_ops fixed_voltage_ops = {
 208 };
 209
 210 static const struct regulator_ops fixed_voltage_clkenabled_ops = {
 211         .enable = reg_clock_enable,
 212         .disable = reg_clock_disable,
 213         .is_enabled = reg_is_enabled,
 214 };
 215
 216 static const struct regulator_ops fixed_voltage_domain_ops = {
 217         .enable = reg_domain_enable,
 218         .disable = reg_domain_disable,
 219         .is_enabled = reg_is_enabled,
 220 };
 221
 222 static int reg_fixed_voltage_probe(struct platform_device *pdev)
 223 {
 224         struct device *dev = &pdev->dev;
 225         struct fixed_voltage_config *config;
 226         struct fixed_voltage_data *drvdata;
 227         const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
 228         struct regulator_config cfg = { };
 229         enum gpiod_flags gflags;
 230         int ret;
 231
 232         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 233                                GFP_KERNEL);
 234         if (!drvdata)
 235                 return -ENOMEM;
 236
 237         if (pdev->dev.of_node) {
 238                 config = of_get_fixed_voltage_config(&pdev->dev,
 239                                                      &drvdata->desc);
 240                 if (IS_ERR(config))
 241                         return PTR_ERR(config);
 242         } else {
 243                 config = dev_get_platdata(&pdev->dev);
 244         }
 245
 246         if (!config)
 247                 return -ENOMEM;
 248
 249         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 250                                           config->supply_name,
 251                                           GFP_KERNEL);
 252         if (drvdata->desc.name == NULL) {
 253                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 254                 return -ENOMEM;
 255         }
 256         drvdata->desc.type = REGULATOR_VOLTAGE;
 257         drvdata->desc.owner = THIS_MODULE;
 258
 259         if (drvtype && drvtype->has_enable_clock) {
 260                 drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
 261
 262                 drvdata->enable_clock = devm_clk_get(dev, NULL);
 263                 if (IS_ERR(drvdata->enable_clock)) {
 264                         dev_err(dev, "Can't get enable-clock from devicetree\n");
 265                         return PTR_ERR(drvdata->enable_clock);
 266                 }
 267         } else if (drvtype && drvtype->has_performance_state) {
 268                 drvdata->desc.ops = &fixed_voltage_domain_ops;
 269
 270                 drvdata->performance_state = of_get_required_opp_performance_state(dev->of_node, 0);
 271                 if (drvdata->performance_state < 0) {
 272                         dev_err(dev, "Can't get performance state from devicetree\n");
 273                         return drvdata->performance_state;
 274                 }
 275         } else {
 276                 drvdata->desc.ops = &fixed_voltage_ops;
 277         }
 278
 279         drvdata->desc.enable_time = config->startup_delay;
 280         drvdata->desc.off_on_delay = config->off_on_delay;
 281
 282         if (config->input_supply) {
 283                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 284                                             config->input_supply,
 285                                             GFP_KERNEL);
 286                 if (!drvdata->desc.supply_name)
 287                         return -ENOMEM;
 288         }
 289
 290         if (config->microvolts)
 291                 drvdata->desc.n_voltages = 1;
 292
 293         drvdata->desc.fixed_uV = config->microvolts;
 294
 295         /*
 296          * The signal will be inverted by the GPIO core if flagged so in the
 297          * descriptor.
 298          */
 299         if (config->enabled_at_boot)
 300                 gflags = GPIOD_OUT_HIGH;
 301         else
 302                 gflags = GPIOD_OUT_LOW;
 303
 304         /*
 305          * Some fixed regulators share the enable line between two
 306          * regulators which makes it necessary to get a handle on the
 307          * same descriptor for two different consumers. This will get
 308          * the GPIO descriptor, but only the first call will initialize
 309          * it so any flags such as inversion or open drain will only
 310          * be set up by the first caller and assumed identical on the
 311          * next caller.
 312          *
 313          * FIXME: find a better way to deal with this.
 314          */
 315         gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 316
 317         /*
 318          * Do not use devm* here: the regulator core takes over the
 319          * lifecycle management of the GPIO descriptor.
 320          */
 321         cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
 322         if (IS_ERR(cfg.ena_gpiod))
 323                 return dev_err_probe(&pdev->dev, PTR_ERR(cfg.ena_gpiod),
 324                                      "can't get GPIO\n");
 325
 326         cfg.dev = &pdev->dev;
 327         cfg.init_data = config->init_data;
 328         cfg.driver_data = drvdata;
 329         cfg.of_node = pdev->dev.of_node;
 330
 331         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 332                                                &cfg);
 333         if (IS_ERR(drvdata->dev)) {
 334                 ret = dev_err_probe(&pdev->dev, PTR_ERR(drvdata->dev),
 335                                     "Failed to register regulator: %ld\n",
 336                                     PTR_ERR(drvdata->dev));
 337                 return ret;
 338         }
 339
 340         platform_set_drvdata(pdev, drvdata);
 341
 342         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 343                 drvdata->desc.fixed_uV);
 344
 345         ret = reg_fixed_get_irqs(dev, drvdata);
 346         if (ret)
 347                 return ret;
 348
 349         return 0;
 350 }
 351
 352 #if defined(CONFIG_OF)
 353 static const struct fixed_dev_type fixed_voltage_data = {
 354         .has_enable_clock = false,
 355 };
 356
 357 static const struct fixed_dev_type fixed_clkenable_data = {
 358         .has_enable_clock = true,
 359 };
 360
 361 static const struct fixed_dev_type fixed_domain_data = {
 362         .has_performance_state = true,
 363 };
 364
 365 static const struct of_device_id fixed_of_match[] = {
 366         {
 367                 .compatible = "regulator-fixed",
 368                 .data = &fixed_voltage_data,
 369         },
 370         {
 371                 .compatible = "regulator-fixed-clock",
 372                 .data = &fixed_clkenable_data,
 373         },
 374         {
 375                 .compatible = "regulator-fixed-domain",
 376                 .data = &fixed_domain_data,
 377         },
 378         {
 379         },
 380 };
 381 MODULE_DEVICE_TABLE(of, fixed_of_match);
 382 #endif
 383
 384 static struct platform_driver regulator_fixed_voltage_driver = {
 385         .probe          = reg_fixed_voltage_probe,
 386         .driver         = {
 387                 .name           = "reg-fixed-voltage",
 388                 .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
 389                 .of_match_table = of_match_ptr(fixed_of_match),
 390         },
 391 };
 392
 393 static int __init regulator_fixed_voltage_init(void)
 394 {
 395         return platform_driver_register(&regulator_fixed_voltage_driver);
 396 }
 397 subsys_initcall(regulator_fixed_voltage_init);
 398
 399 static void __exit regulator_fixed_voltage_exit(void)
 400 {
 401         platform_driver_unregister(&regulator_fixed_voltage_driver);
 402 }
 403 module_exit(regulator_fixed_voltage_exit);
 404
 405 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 406 MODULE_DESCRIPTION("Fixed voltage regulator");
 407 MODULE_LICENSE("GPL");
 408 MODULE_ALIAS("platform:reg-fixed-voltage");