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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         const __be32 *delay;
 54         struct regulator_init_data *init_data;
 55 
 56         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
 57                                                                  GFP_KERNEL);
 58         if (!config)
 59                 return ERR_PTR(-ENOMEM);
 60 
 61         config->init_data = of_get_regulator_init_data(dev, dev->of_node);
 62         if (!config->init_data)
 63                 return ERR_PTR(-EINVAL);
 64 
 65         init_data = config->init_data;
 66         init_data->constraints.apply_uV = 0;
 67 
 68         config->supply_name = init_data->constraints.name;
 69         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
 70                 config->microvolts = init_data->constraints.min_uV;
 71         } else {
 72                 dev_err(dev,
 73                          "Fixed regulator specified with variable voltages\n");
 74                 return ERR_PTR(-EINVAL);
 75         }
 76 
 77         if (init_data->constraints.boot_on)
 78                 config->enabled_at_boot = true;
 79 
 80         config->gpio = of_get_named_gpio(np, "gpio", 0);
 81         /*
 82          * of_get_named_gpio() currently returns ENODEV rather than
 83          * EPROBE_DEFER. This code attempts to be compatible with both
 84          * for now; the ENODEV check can be removed once the API is fixed.
 85          * of_get_named_gpio() doesn't differentiate between a missing
 86          * property (which would be fine here, since the GPIO is optional)
 87          * and some other error. Patches have been posted for both issues.
 88          * Once they are check in, we should replace this with:
 89          * if (config->gpio < 0 && config->gpio != -ENOENT)
 90          */
 91         if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER))
 92                 return ERR_PTR(-EPROBE_DEFER);
 93 
 94         delay = of_get_property(np, "startup-delay-us", NULL);
 95         if (delay)
 96                 config->startup_delay = be32_to_cpu(*delay);
 97 
 98         if (of_find_property(np, "enable-active-high", NULL))
 99                 config->enable_high = true;
100 
101         if (of_find_property(np, "gpio-open-drain", NULL))
102                 config->gpio_is_open_drain = true;
103 
104         if (of_find_property(np, "vin-supply", NULL))
105                 config->input_supply = "vin";
106 
107         return config;
108 }
109 
110 static struct regulator_ops fixed_voltage_ops = {
111 };
112 
113 static int reg_fixed_voltage_probe(struct platform_device *pdev)
114 {
115         struct fixed_voltage_config *config;
116         struct fixed_voltage_data *drvdata;
117         struct regulator_config cfg = { };
118         int ret;
119 
120         if (pdev->dev.of_node) {
121                 config = of_get_fixed_voltage_config(&pdev->dev);
122                 if (IS_ERR(config))
123                         return PTR_ERR(config);
124         } else {
125                 config = dev_get_platdata(&pdev->dev);
126         }
127 
128         if (!config)
129                 return -ENOMEM;
130 
131         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
132                                GFP_KERNEL);
133         if (!drvdata)
134                 return -ENOMEM;
135 
136         drvdata->desc.name = devm_kstrdup(&pdev->dev,
137                                           config->supply_name,
138                                           GFP_KERNEL);
139         if (drvdata->desc.name == NULL) {
140                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
141                 return -ENOMEM;
142         }
143         drvdata->desc.type = REGULATOR_VOLTAGE;
144         drvdata->desc.owner = THIS_MODULE;
145         drvdata->desc.ops = &fixed_voltage_ops;
146 
147         drvdata->desc.enable_time = config->startup_delay;
148 
149         if (config->input_supply) {
150                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
151                                             config->input_supply,
152                                             GFP_KERNEL);
153                 if (!drvdata->desc.supply_name) {
154                         dev_err(&pdev->dev,
155                                 "Failed to allocate input supply\n");
156                         return -ENOMEM;
157                 }
158         }
159 
160         if (config->microvolts)
161                 drvdata->desc.n_voltages = 1;
162 
163         drvdata->desc.fixed_uV = config->microvolts;
164 
165         if (config->gpio >= 0)
166                 cfg.ena_gpio = config->gpio;
167         cfg.ena_gpio_invert = !config->enable_high;
168         if (config->enabled_at_boot) {
169                 if (config->enable_high)
170                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
171                 else
172                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
173         } else {
174                 if (config->enable_high)
175                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
176                 else
177                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
178         }
179         if (config->gpio_is_open_drain)
180                 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
181 
182         cfg.dev = &pdev->dev;
183         cfg.init_data = config->init_data;
184         cfg.driver_data = drvdata;
185         cfg.of_node = pdev->dev.of_node;
186 
187         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
188                                                &cfg);
189         if (IS_ERR(drvdata->dev)) {
190                 ret = PTR_ERR(drvdata->dev);
191                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
192                 return ret;
193         }
194 
195         platform_set_drvdata(pdev, drvdata);
196 
197         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
198                 drvdata->desc.fixed_uV);
199 
200         return 0;
201 }
202 
203 #if defined(CONFIG_OF)
204 static const struct of_device_id fixed_of_match[] = {
205         { .compatible = "regulator-fixed", },
206         {},
207 };
208 MODULE_DEVICE_TABLE(of, fixed_of_match);
209 #endif
210 
211 static struct platform_driver regulator_fixed_voltage_driver = {
212         .probe          = reg_fixed_voltage_probe,
213         .driver         = {
214                 .name           = "reg-fixed-voltage",
215                 .owner          = THIS_MODULE,
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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