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/regulator/driver.h>
  22 #include <linux/regulator/fixed.h>
  23 #include <linux/gpio/consumer.h>
  24 #include <linux/slab.h>
  25 #include <linux/of.h>
  26 #include <linux/regulator/of_regulator.h>
  27 #include <linux/regulator/machine.h>
  28
  29 struct fixed_voltage_data {
  30         struct regulator_desc desc;
  31         struct regulator_dev *dev;
  32 };
  33
  34
  35 /**
  36  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
  37  * @dev: device requesting for fixed_voltage_config
  38  * @desc: regulator description
  39  *
  40  * Populates fixed_voltage_config structure by extracting data from device
  41  * tree node, returns a pointer to the populated structure of NULL if memory
  42  * alloc fails.
  43  */
  44 static struct fixed_voltage_config *
  45 of_get_fixed_voltage_config(struct device *dev,
  46                             const struct regulator_desc *desc)
  47 {
  48         struct fixed_voltage_config *config;
  49         struct device_node *np = dev->of_node;
  50         struct regulator_init_data *init_data;
  51
  52         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
  53                                                                  GFP_KERNEL);
  54         if (!config)
  55                 return ERR_PTR(-ENOMEM);
  56
  57         config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
  58         if (!config->init_data)
  59                 return ERR_PTR(-EINVAL);
  60
  61         init_data = config->init_data;
  62         init_data->constraints.apply_uV = 0;
  63
  64         config->supply_name = init_data->constraints.name;
  65         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
  66                 config->microvolts = init_data->constraints.min_uV;
  67         } else {
  68                 dev_err(dev,
  69                          "Fixed regulator specified with variable voltages\n");
  70                 return ERR_PTR(-EINVAL);
  71         }
  72
  73         if (init_data->constraints.boot_on)
  74                 config->enabled_at_boot = true;
  75
  76         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
  77
  78         if (of_find_property(np, "vin-supply", NULL))
  79                 config->input_supply = "vin";
  80
  81         return config;
  82 }
  83
  84 static struct regulator_ops fixed_voltage_ops = {
  85 };
  86
  87 static int reg_fixed_voltage_probe(struct platform_device *pdev)
  88 {
  89         struct fixed_voltage_config *config;
  90         struct fixed_voltage_data *drvdata;
  91         struct regulator_config cfg = { };
  92         enum gpiod_flags gflags;
  93         int ret;
  94
  95         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
  96                                GFP_KERNEL);
  97         if (!drvdata)
  98                 return -ENOMEM;
  99
 100         if (pdev->dev.of_node) {
 101                 config = of_get_fixed_voltage_config(&pdev->dev,
 102                                                      &drvdata->desc);
 103                 if (IS_ERR(config))
 104                         return PTR_ERR(config);
 105         } else {
 106                 config = dev_get_platdata(&pdev->dev);
 107         }
 108
 109         if (!config)
 110                 return -ENOMEM;
 111
 112         drvdata->desc.name = devm_kstrdup(&pdev->dev,
 113                                           config->supply_name,
 114                                           GFP_KERNEL);
 115         if (drvdata->desc.name == NULL) {
 116                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 117                 return -ENOMEM;
 118         }
 119         drvdata->desc.type = REGULATOR_VOLTAGE;
 120         drvdata->desc.owner = THIS_MODULE;
 121         drvdata->desc.ops = &fixed_voltage_ops;
 122
 123         drvdata->desc.enable_time = config->startup_delay;
 124
 125         if (config->input_supply) {
 126                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
 127                                             config->input_supply,
 128                                             GFP_KERNEL);
 129                 if (!drvdata->desc.supply_name) {
 130                         dev_err(&pdev->dev,
 131                                 "Failed to allocate input supply\n");
 132                         return -ENOMEM;
 133                 }
 134         }
 135
 136         if (config->microvolts)
 137                 drvdata->desc.n_voltages = 1;
 138
 139         drvdata->desc.fixed_uV = config->microvolts;
 140
 141         /*
 142          * The signal will be inverted by the GPIO core if flagged so in the
 143          * decriptor.
 144          */
 145         if (config->enabled_at_boot)
 146                 gflags = GPIOD_OUT_HIGH;
 147         else
 148                 gflags = GPIOD_OUT_LOW;
 149
 150         /*
 151          * Some fixed regulators share the enable line between two
 152          * regulators which makes it necessary to get a handle on the
 153          * same descriptor for two different consumers. This will get
 154          * the GPIO descriptor, but only the first call will initialize
 155          * it so any flags such as inversion or open drain will only
 156          * be set up by the first caller and assumed identical on the
 157          * next caller.
 158          *
 159          * FIXME: find a better way to deal with this.
 160          */
 161         gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 162
 163         /*
 164          * Do not use devm* here: the regulator core takes over the
 165          * lifecycle management of the GPIO descriptor.
 166          */
 167         cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
 168         if (IS_ERR(cfg.ena_gpiod))
 169                 return PTR_ERR(cfg.ena_gpiod);
 170
 171         cfg.dev = &pdev->dev;
 172         cfg.init_data = config->init_data;
 173         cfg.driver_data = drvdata;
 174         cfg.of_node = pdev->dev.of_node;
 175
 176         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
 177                                                &cfg);
 178         if (IS_ERR(drvdata->dev)) {
 179                 ret = PTR_ERR(drvdata->dev);
 180                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 181                 return ret;
 182         }
 183
 184         platform_set_drvdata(pdev, drvdata);
 185
 186         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 187                 drvdata->desc.fixed_uV);
 188
 189         return 0;
 190 }
 191
 192 #if defined(CONFIG_OF)
 193 static const struct of_device_id fixed_of_match[] = {
 194         { .compatible = "regulator-fixed", },
 195         {},
 196 };
 197 MODULE_DEVICE_TABLE(of, fixed_of_match);
 198 #endif
 199
 200 static struct platform_driver regulator_fixed_voltage_driver = {
 201         .probe          = reg_fixed_voltage_probe,
 202         .driver         = {
 203                 .name           = "reg-fixed-voltage",
 204                 .of_match_table = of_match_ptr(fixed_of_match),
 205         },
 206 };
 207
 208 static int __init regulator_fixed_voltage_init(void)
 209 {
 210         return platform_driver_register(&regulator_fixed_voltage_driver);
 211 }
 212 subsys_initcall(regulator_fixed_voltage_init);
 213
 214 static void __exit regulator_fixed_voltage_exit(void)
 215 {
 216         platform_driver_unregister(&regulator_fixed_voltage_driver);
 217 }
 218 module_exit(regulator_fixed_voltage_exit);
 219
 220 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 221 MODULE_DESCRIPTION("Fixed voltage regulator");
 222 MODULE_LICENSE("GPL");
 223 MODULE_ALIAS("platform:reg-fixed-voltage");