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