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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  *
 44  * Populates fixed_voltage_config structure by extracting data from device
 45  * tree node, returns a pointer to the populated structure of NULL if memory
 46  * alloc fails.
 47  */
 48 static struct fixed_voltage_config *
 49 of_get_fixed_voltage_config(struct device *dev)
 50 {
 51         struct fixed_voltage_config *config;
 52         struct device_node *np = dev->of_node;
 53         struct regulator_init_data *init_data;
 54 
 55         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
 56                                                                  GFP_KERNEL);
 57         if (!config)
 58                 return ERR_PTR(-ENOMEM);
 59 
 60         config->init_data = of_get_regulator_init_data(dev, dev->of_node);
 61         if (!config->init_data)
 62                 return ERR_PTR(-EINVAL);
 63 
 64         init_data = config->init_data;
 65         init_data->constraints.apply_uV = 0;
 66 
 67         config->supply_name = init_data->constraints.name;
 68         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
 69                 config->microvolts = init_data->constraints.min_uV;
 70         } else {
 71                 dev_err(dev,
 72                          "Fixed regulator specified with variable voltages\n");
 73                 return ERR_PTR(-EINVAL);
 74         }
 75 
 76         if (init_data->constraints.boot_on)
 77                 config->enabled_at_boot = true;
 78 
 79         config->gpio = of_get_named_gpio(np, "gpio", 0);
 80         /*
 81          * of_get_named_gpio() currently returns ENODEV rather than
 82          * EPROBE_DEFER. This code attempts to be compatible with both
 83          * for now; the ENODEV check can be removed once the API is fixed.
 84          * of_get_named_gpio() doesn't differentiate between a missing
 85          * property (which would be fine here, since the GPIO is optional)
 86          * and some other error. Patches have been posted for both issues.
 87          * Once they are check in, we should replace this with:
 88          * if (config->gpio < 0 && config->gpio != -ENOENT)
 89          */
 90         if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER))
 91                 return ERR_PTR(-EPROBE_DEFER);
 92 
 93         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 94 
 95         config->enable_high = of_property_read_bool(np, "enable-active-high");
 96         config->gpio_is_open_drain = of_property_read_bool(np,
 97                                                            "gpio-open-drain");
 98 
 99         if (of_find_property(np, "vin-supply", NULL))
100                 config->input_supply = "vin";
101 
102         return config;
103 }
104 
105 static struct regulator_ops fixed_voltage_ops = {
106 };
107 
108 static int reg_fixed_voltage_probe(struct platform_device *pdev)
109 {
110         struct fixed_voltage_config *config;
111         struct fixed_voltage_data *drvdata;
112         struct regulator_config cfg = { };
113         int ret;
114 
115         if (pdev->dev.of_node) {
116                 config = of_get_fixed_voltage_config(&pdev->dev);
117                 if (IS_ERR(config))
118                         return PTR_ERR(config);
119         } else {
120                 config = dev_get_platdata(&pdev->dev);
121         }
122 
123         if (!config)
124                 return -ENOMEM;
125 
126         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
127                                GFP_KERNEL);
128         if (!drvdata)
129                 return -ENOMEM;
130 
131         drvdata->desc.name = devm_kstrdup(&pdev->dev,
132                                           config->supply_name,
133                                           GFP_KERNEL);
134         if (drvdata->desc.name == NULL) {
135                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
136                 return -ENOMEM;
137         }
138         drvdata->desc.type = REGULATOR_VOLTAGE;
139         drvdata->desc.owner = THIS_MODULE;
140         drvdata->desc.ops = &fixed_voltage_ops;
141 
142         drvdata->desc.enable_time = config->startup_delay;
143 
144         if (config->input_supply) {
145                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
146                                             config->input_supply,
147                                             GFP_KERNEL);
148                 if (!drvdata->desc.supply_name) {
149                         dev_err(&pdev->dev,
150                                 "Failed to allocate input supply\n");
151                         return -ENOMEM;
152                 }
153         }
154 
155         if (config->microvolts)
156                 drvdata->desc.n_voltages = 1;
157 
158         drvdata->desc.fixed_uV = config->microvolts;
159 
160         if (config->gpio >= 0)
161                 cfg.ena_gpio = config->gpio;
162         cfg.ena_gpio_invert = !config->enable_high;
163         if (config->enabled_at_boot) {
164                 if (config->enable_high)
165                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
166                 else
167                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
168         } else {
169                 if (config->enable_high)
170                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
171                 else
172                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
173         }
174         if (config->gpio_is_open_drain)
175                 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
176 
177         cfg.dev = &pdev->dev;
178         cfg.init_data = config->init_data;
179         cfg.driver_data = drvdata;
180         cfg.of_node = pdev->dev.of_node;
181 
182         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
183                                                &cfg);
184         if (IS_ERR(drvdata->dev)) {
185                 ret = PTR_ERR(drvdata->dev);
186                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
187                 return ret;
188         }
189 
190         platform_set_drvdata(pdev, drvdata);
191 
192         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
193                 drvdata->desc.fixed_uV);
194 
195         return 0;
196 }
197 
198 #if defined(CONFIG_OF)
199 static const struct of_device_id fixed_of_match[] = {
200         { .compatible = "regulator-fixed", },
201         {},
202 };
203 MODULE_DEVICE_TABLE(of, fixed_of_match);
204 #endif
205 
206 static struct platform_driver regulator_fixed_voltage_driver = {
207         .probe          = reg_fixed_voltage_probe,
208         .driver         = {
209                 .name           = "reg-fixed-voltage",
210                 .owner          = THIS_MODULE,
211                 .of_match_table = of_match_ptr(fixed_of_match),
212         },
213 };
214 
215 static int __init regulator_fixed_voltage_init(void)
216 {
217         return platform_driver_register(&regulator_fixed_voltage_driver);
218 }
219 subsys_initcall(regulator_fixed_voltage_init);
220 
221 static void __exit regulator_fixed_voltage_exit(void)
222 {
223         platform_driver_unregister(&regulator_fixed_voltage_driver);
224 }
225 module_exit(regulator_fixed_voltage_exit);
226 
227 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
228 MODULE_DESCRIPTION("Fixed voltage regulator");
229 MODULE_LICENSE("GPL");
230 MODULE_ALIAS("platform:reg-fixed-voltage");
231 

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