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