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Linux/drivers/regulator/fixed.c

  1 /*
  2  * fixed.c
  3  *
  4  * Copyright 2008 Wolfson Microelectronics PLC.
  5  *
  6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  7  *
  8  * Copyright (c) 2009 Nokia Corporation
  9  * Roger Quadros <ext-roger.quadros@nokia.com>
 10  *
 11  * This program is free software; you can redistribute it and/or
 12  * modify it under the terms of the GNU General Public License as
 13  * published by the Free Software Foundation; either version 2 of the
 14  * License, or (at your option) any later version.
 15  *
 16  * This is useful for systems with mixed controllable and
 17  * non-controllable regulators, as well as for allowing testing on
 18  * systems with no controllable regulators.
 19  */
 20 
 21 #include <linux/err.h>
 22 #include <linux/mutex.h>
 23 #include <linux/module.h>
 24 #include <linux/platform_device.h>
 25 #include <linux/regulator/driver.h>
 26 #include <linux/regulator/fixed.h>
 27 #include <linux/gpio.h>
 28 #include <linux/slab.h>
 29 #include <linux/of.h>
 30 #include <linux/of_gpio.h>
 31 #include <linux/regulator/of_regulator.h>
 32 #include <linux/regulator/machine.h>
 33 
 34 struct fixed_voltage_data {
 35         struct regulator_desc desc;
 36         struct regulator_dev *dev;
 37 };
 38 
 39 
 40 /**
 41  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
 42  * @dev: device requesting for fixed_voltage_config
 43  * @desc: regulator description
 44  *
 45  * Populates fixed_voltage_config structure by extracting data from device
 46  * tree node, returns a pointer to the populated structure of NULL if memory
 47  * alloc fails.
 48  */
 49 static struct fixed_voltage_config *
 50 of_get_fixed_voltage_config(struct device *dev,
 51                             const struct regulator_desc *desc)
 52 {
 53         struct fixed_voltage_config *config;
 54         struct device_node *np = dev->of_node;
 55         struct regulator_init_data *init_data;
 56 
 57         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
 58                                                                  GFP_KERNEL);
 59         if (!config)
 60                 return ERR_PTR(-ENOMEM);
 61 
 62         config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
 63         if (!config->init_data)
 64                 return ERR_PTR(-EINVAL);
 65 
 66         init_data = config->init_data;
 67         init_data->constraints.apply_uV = 0;
 68 
 69         config->supply_name = init_data->constraints.name;
 70         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
 71                 config->microvolts = init_data->constraints.min_uV;
 72         } else {
 73                 dev_err(dev,
 74                          "Fixed regulator specified with variable voltages\n");
 75                 return ERR_PTR(-EINVAL);
 76         }
 77 
 78         if (init_data->constraints.boot_on)
 79                 config->enabled_at_boot = true;
 80 
 81         config->gpio = of_get_named_gpio(np, "gpio", 0);
 82         /*
 83          * of_get_named_gpio() currently returns ENODEV rather than
 84          * EPROBE_DEFER. This code attempts to be compatible with both
 85          * for now; the ENODEV check can be removed once the API is fixed.
 86          * of_get_named_gpio() doesn't differentiate between a missing
 87          * property (which would be fine here, since the GPIO is optional)
 88          * and some other error. Patches have been posted for both issues.
 89          * Once they are check in, we should replace this with:
 90          * if (config->gpio < 0 && config->gpio != -ENOENT)
 91          */
 92         if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER))
 93                 return ERR_PTR(-EPROBE_DEFER);
 94 
 95         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 96 
 97         config->enable_high = of_property_read_bool(np, "enable-active-high");
 98         config->gpio_is_open_drain = of_property_read_bool(np,
 99                                                            "gpio-open-drain");
100 
101         if (of_find_property(np, "vin-supply", NULL))
102                 config->input_supply = "vin";
103 
104         return config;
105 }
106 
107 static struct regulator_ops fixed_voltage_ops = {
108 };
109 
110 static int reg_fixed_voltage_probe(struct platform_device *pdev)
111 {
112         struct fixed_voltage_config *config;
113         struct fixed_voltage_data *drvdata;
114         struct regulator_config cfg = { };
115         int ret;
116 
117         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
118                                GFP_KERNEL);
119         if (!drvdata)
120                 return -ENOMEM;
121 
122         if (pdev->dev.of_node) {
123                 config = of_get_fixed_voltage_config(&pdev->dev,
124                                                      &drvdata->desc);
125                 if (IS_ERR(config))
126                         return PTR_ERR(config);
127         } else {
128                 config = dev_get_platdata(&pdev->dev);
129         }
130 
131         if (!config)
132                 return -ENOMEM;
133 
134         drvdata->desc.name = devm_kstrdup(&pdev->dev,
135                                           config->supply_name,
136                                           GFP_KERNEL);
137         if (drvdata->desc.name == NULL) {
138                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
139                 return -ENOMEM;
140         }
141         drvdata->desc.type = REGULATOR_VOLTAGE;
142         drvdata->desc.owner = THIS_MODULE;
143         drvdata->desc.ops = &fixed_voltage_ops;
144 
145         drvdata->desc.enable_time = config->startup_delay;
146 
147         if (config->input_supply) {
148                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
149                                             config->input_supply,
150                                             GFP_KERNEL);
151                 if (!drvdata->desc.supply_name) {
152                         dev_err(&pdev->dev,
153                                 "Failed to allocate input supply\n");
154                         return -ENOMEM;
155                 }
156         }
157 
158         if (config->microvolts)
159                 drvdata->desc.n_voltages = 1;
160 
161         drvdata->desc.fixed_uV = config->microvolts;
162 
163         if (gpio_is_valid(config->gpio)) {
164                 cfg.ena_gpio = config->gpio;
165                 if (pdev->dev.of_node)
166                         cfg.ena_gpio_initialized = true;
167         }
168         cfg.ena_gpio_invert = !config->enable_high;
169         if (config->enabled_at_boot) {
170                 if (config->enable_high)
171                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
172                 else
173                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
174         } else {
175                 if (config->enable_high)
176                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
177                 else
178                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
179         }
180         if (config->gpio_is_open_drain)
181                 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
182 
183         cfg.dev = &pdev->dev;
184         cfg.init_data = config->init_data;
185         cfg.driver_data = drvdata;
186         cfg.of_node = pdev->dev.of_node;
187 
188         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
189                                                &cfg);
190         if (IS_ERR(drvdata->dev)) {
191                 ret = PTR_ERR(drvdata->dev);
192                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
193                 return ret;
194         }
195 
196         platform_set_drvdata(pdev, drvdata);
197 
198         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
199                 drvdata->desc.fixed_uV);
200 
201         return 0;
202 }
203 
204 #if defined(CONFIG_OF)
205 static const struct of_device_id fixed_of_match[] = {
206         { .compatible = "regulator-fixed", },
207         {},
208 };
209 MODULE_DEVICE_TABLE(of, fixed_of_match);
210 #endif
211 
212 static struct platform_driver regulator_fixed_voltage_driver = {
213         .probe          = reg_fixed_voltage_probe,
214         .driver         = {
215                 .name           = "reg-fixed-voltage",
216                 .of_match_table = of_match_ptr(fixed_of_match),
217         },
218 };
219 
220 static int __init regulator_fixed_voltage_init(void)
221 {
222         return platform_driver_register(&regulator_fixed_voltage_driver);
223 }
224 subsys_initcall(regulator_fixed_voltage_init);
225 
226 static void __exit regulator_fixed_voltage_exit(void)
227 {
228         platform_driver_unregister(&regulator_fixed_voltage_driver);
229 }
230 module_exit(regulator_fixed_voltage_exit);
231 
232 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
233 MODULE_DESCRIPTION("Fixed voltage regulator");
234 MODULE_LICENSE("GPL");
235 MODULE_ALIAS("platform:reg-fixed-voltage");
236 

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