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 error code 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, returns a pointer to the populated structure of NULL if memory
 162  * alloc fails.
 163  */
 164 static struct fixed_voltage_config *
 165 of_get_fixed_voltage_config(struct device *dev,
 166                             const struct regulator_desc *desc)
 167 {
 168         struct fixed_voltage_config *config;
 169         struct device_node *np = dev->of_node;
 170         struct regulator_init_data *init_data;
 171
 172         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
 173                                                                  GFP_KERNEL);
 174         if (!config)
 175                 return ERR_PTR(-ENOMEM);
 176
 177         config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
 178         if (!config->init_data)
 179                 return ERR_PTR(-EINVAL);
 180
 181         init_data = config->init_data;
 182         init_data->constraints.apply_uV = 0;
 183
 184         config->supply_name = init_data->constraints.name;
 185         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
 186                 config->microvolts = init_data->constraints.min_uV;
 187         } else {
 188                 dev_err(dev,
 189                          "Fixed regulator specified with variable voltages\n");
 190                 return ERR_PTR(-EINVAL);
 191         }
 192
 193         if (init_data->constraints.boot_on)
 194                 config->enabled_at_boot = true;
 195
 196         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 197         of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
 198
 199         if (of_property_present(np, "vin-supply"))
 200                 config->input_supply = "vin";
 201
 202         return config;
 203 }
 204
 205 static const struct regulator_ops fixed_voltage_ops = {
 206 };
 207
 208 static const struct regulator_ops fixed_voltage_clkenabled_ops = {
 209         .enable = reg_clock_enable,
 210         .disable = reg_clock_disable,
 211         .is_enabled = reg_is_enabled,
 212 };
 213
 214 static const struct regulator_ops fixed_voltage_domain_ops = {
 215         .enable = reg_domain_enable,
 216         .disable = reg_domain_disable,
 217         .is_enabled = reg_is_enabled,
 218 };
 219
 220 static int reg_fixed_voltage_probe(struct platform_device *pdev)
 221 {
 222         struct device *dev = &pdev->dev;
 223         struct fixed_voltage_config *config;
 224         struct fixed_voltage_data *drvdata;
 225         const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
 226         struct regulator_config cfg = { };
 227         enum gpiod_flags gflags;
 228         int ret;
 229
 230         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
 231                                GFP_KERNEL);
 232         if (!drvdata)
 233                 return -ENOMEM;
 234
 235         if (pdev->dev.of_node) {
 236                 config = of_get_fixed_voltage_config(&pdev->dev,
 237                                                      &drvdata->desc);
 238                 if (IS_ERR(config))
 239                         return PTR_ERR(config);
 240         } else {
 241                 config = dev_get_platdata(&pdev->dev);
 242         }
 243
 244         if (!config)
 245                 return -ENOMEM;
 246
 247         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 248                                           config->supply_name,
 249                                           GFP_KERNEL);
 250         if (drvdata->desc.name == NULL) {
 251                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 252                 return -ENOMEM;
 253         }
 254         drvdata->desc.type = REGULATOR_VOLTAGE;
 255         drvdata->desc.owner = THIS_MODULE;
 256
 257         if (drvtype && drvtype->has_enable_clock) {
 258                 drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
 259
 260                 drvdata->enable_clock = devm_clk_get(dev, NULL);
 261                 if (IS_ERR(drvdata->enable_clock)) {
 262                         dev_err(dev, "Can't get enable-clock from devicetree\n");
 263                         return PTR_ERR(drvdata->enable_clock);
 264                 }
 265         } else if (drvtype && drvtype->has_performance_state) {
 266                 drvdata->desc.ops = &fixed_voltage_domain_ops;
 267
 268                 drvdata->performance_state = of_get_required_opp_performance_state(dev->of_node, 0);
 269                 if (drvdata->performance_state < 0) {
 270                         dev_err(dev, "Can't get performance state from devicetree\n");
 271                         return drvdata->performance_state;
 272                 }
 273         } else {
 274                 drvdata->desc.ops = &fixed_voltage_ops;
 275         }
 276
 277         drvdata->desc.enable_time = config->startup_delay;
 278         drvdata->desc.off_on_delay = config->off_on_delay;
 279
 280         if (config->input_supply) {
 281                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 282                                             config->input_supply,
 283                                             GFP_KERNEL);
 284                 if (!drvdata->desc.supply_name)
 285                         return -ENOMEM;
 286         }
 287
 288         if (config->microvolts)
 289                 drvdata->desc.n_voltages = 1;
 290
 291         drvdata->desc.fixed_uV = config->microvolts;
 292
 293         /*
 294          * The signal will be inverted by the GPIO core if flagged so in the
 295          * descriptor.
 296          */
 297         if (config->enabled_at_boot)
 298                 gflags = GPIOD_OUT_HIGH;
 299         else
 300                 gflags = GPIOD_OUT_LOW;
 301
 302         /*
 303          * Some fixed regulators share the enable line between two
 304          * regulators which makes it necessary to get a handle on the
 305          * same descriptor for two different consumers. This will get
 306          * the GPIO descriptor, but only the first call will initialize
 307          * it so any flags such as inversion or open drain will only
 308          * be set up by the first caller and assumed identical on the
 309          * next caller.
 310          *
 311          * FIXME: find a better way to deal with this.
 312          */
 313         gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 314
 315         /*
 316          * Do not use devm* here: the regulator core takes over the
 317          * lifecycle management of the GPIO descriptor.
 318          */
 319         cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
 320         if (IS_ERR(cfg.ena_gpiod))
 321                 return dev_err_probe(&pdev->dev, PTR_ERR(cfg.ena_gpiod),
 322                                      "can't get GPIO\n");
 323
 324         cfg.dev = &pdev->dev;
 325         cfg.init_data = config->init_data;
 326         cfg.driver_data = drvdata;
 327         cfg.of_node = pdev->dev.of_node;
 328
 329         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 330                                                &cfg);
 331         if (IS_ERR(drvdata->dev)) {
 332                 ret = dev_err_probe(&pdev->dev, PTR_ERR(drvdata->dev),
 333                                     "Failed to register regulator: %ld\n",
 334                                     PTR_ERR(drvdata->dev));
 335                 return ret;
 336         }
 337
 338         platform_set_drvdata(pdev, drvdata);
 339
 340         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 341                 drvdata->desc.fixed_uV);
 342
 343         ret = reg_fixed_get_irqs(dev, drvdata);
 344         if (ret)
 345                 return ret;
 346
 347         return 0;
 348 }
 349
 350 #if defined(CONFIG_OF)
 351 static const struct fixed_dev_type fixed_voltage_data = {
 352         .has_enable_clock = false,
 353 };
 354
 355 static const struct fixed_dev_type fixed_clkenable_data = {
 356         .has_enable_clock = true,
 357 };
 358
 359 static const struct fixed_dev_type fixed_domain_data = {
 360         .has_performance_state = true,
 361 };
 362
 363 static const struct of_device_id fixed_of_match[] = {
 364         {
 365                 .compatible = "regulator-fixed",
 366                 .data = &fixed_voltage_data,
 367         },
 368         {
 369                 .compatible = "regulator-fixed-clock",
 370                 .data = &fixed_clkenable_data,
 371         },
 372         {
 373                 .compatible = "regulator-fixed-domain",
 374                 .data = &fixed_domain_data,
 375         },
 376         {
 377         },
 378 };
 379 MODULE_DEVICE_TABLE(of, fixed_of_match);
 380 #endif
 381
 382 static struct platform_driver regulator_fixed_voltage_driver = {
 383         .probe          = reg_fixed_voltage_probe,
 384         .driver         = {
 385                 .name           = "reg-fixed-voltage",
 386                 .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
 387                 .of_match_table = of_match_ptr(fixed_of_match),
 388         },
 389 };
 390
 391 static int __init regulator_fixed_voltage_init(void)
 392 {
 393         return platform_driver_register(&regulator_fixed_voltage_driver);
 394 }
 395 subsys_initcall(regulator_fixed_voltage_init);
 396
 397 static void __exit regulator_fixed_voltage_exit(void)
 398 {
 399         platform_driver_unregister(&regulator_fixed_voltage_driver);
 400 }
 401 module_exit(regulator_fixed_voltage_exit);
 402
 403 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 404 MODULE_DESCRIPTION("Fixed voltage regulator");
 405 MODULE_LICENSE("GPL");
 406 MODULE_ALIAS("platform:reg-fixed-voltage");