4 * Copyright 2008 Wolfson Microelectronics PLC.
6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
8 * Copyright (c) 2009 Nokia Corporation
9 * Roger Quadros <ext-roger.quadros@nokia.com>
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.
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.
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/delay.h>
29 #include <linux/slab.h>
31 #include <linux/of_gpio.h>
32 #include <linux/regulator/of_regulator.h>
33 #include <linux/regulator/machine.h>
35 struct fixed_voltage_data {
36 struct regulator_desc desc;
37 struct regulator_dev *dev;
40 unsigned startup_delay;
47 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
48 * @dev: device requesting for fixed_voltage_config
50 * Populates fixed_voltage_config structure by extracting data from device
51 * tree node, returns a pointer to the populated structure of NULL if memory
54 static struct fixed_voltage_config *
55 of_get_fixed_voltage_config(struct device *dev)
57 struct fixed_voltage_config *config;
58 struct device_node *np = dev->of_node;
60 struct regulator_init_data *init_data;
62 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
67 config->init_data = of_get_regulator_init_data(dev, dev->of_node);
68 if (!config->init_data)
71 init_data = config->init_data;
72 init_data->constraints.apply_uV = 0;
74 config->supply_name = init_data->constraints.name;
75 if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
76 config->microvolts = init_data->constraints.min_uV;
79 "Fixed regulator specified with variable voltages\n");
83 if (init_data->constraints.boot_on)
84 config->enabled_at_boot = true;
86 config->gpio = of_get_named_gpio(np, "gpio", 0);
87 delay = of_get_property(np, "startup-delay-us", NULL);
89 config->startup_delay = be32_to_cpu(*delay);
91 if (of_find_property(np, "enable-active-high", NULL))
92 config->enable_high = true;
97 static int fixed_voltage_is_enabled(struct regulator_dev *dev)
99 struct fixed_voltage_data *data = rdev_get_drvdata(dev);
101 return data->is_enabled;
104 static int fixed_voltage_enable(struct regulator_dev *dev)
106 struct fixed_voltage_data *data = rdev_get_drvdata(dev);
108 if (gpio_is_valid(data->gpio)) {
109 gpio_set_value_cansleep(data->gpio, data->enable_high);
110 data->is_enabled = true;
116 static int fixed_voltage_disable(struct regulator_dev *dev)
118 struct fixed_voltage_data *data = rdev_get_drvdata(dev);
120 if (gpio_is_valid(data->gpio)) {
121 gpio_set_value_cansleep(data->gpio, !data->enable_high);
122 data->is_enabled = false;
128 static int fixed_voltage_enable_time(struct regulator_dev *dev)
130 struct fixed_voltage_data *data = rdev_get_drvdata(dev);
132 return data->startup_delay;
135 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
137 struct fixed_voltage_data *data = rdev_get_drvdata(dev);
139 if (data->microvolts)
140 return data->microvolts;
145 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
148 struct fixed_voltage_data *data = rdev_get_drvdata(dev);
153 return data->microvolts;
156 static struct regulator_ops fixed_voltage_ops = {
157 .is_enabled = fixed_voltage_is_enabled,
158 .enable = fixed_voltage_enable,
159 .disable = fixed_voltage_disable,
160 .enable_time = fixed_voltage_enable_time,
161 .get_voltage = fixed_voltage_get_voltage,
162 .list_voltage = fixed_voltage_list_voltage,
165 static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
167 struct fixed_voltage_config *config;
168 struct fixed_voltage_data *drvdata;
171 if (pdev->dev.of_node)
172 config = of_get_fixed_voltage_config(&pdev->dev);
174 config = pdev->dev.platform_data;
179 drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
180 if (drvdata == NULL) {
181 dev_err(&pdev->dev, "Failed to allocate device data\n");
186 drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
187 if (drvdata->desc.name == NULL) {
188 dev_err(&pdev->dev, "Failed to allocate supply name\n");
192 drvdata->desc.type = REGULATOR_VOLTAGE;
193 drvdata->desc.owner = THIS_MODULE;
194 drvdata->desc.ops = &fixed_voltage_ops;
195 drvdata->desc.n_voltages = 1;
197 drvdata->microvolts = config->microvolts;
198 drvdata->gpio = config->gpio;
199 drvdata->startup_delay = config->startup_delay;
201 if (gpio_is_valid(config->gpio)) {
202 drvdata->enable_high = config->enable_high;
204 /* FIXME: Remove below print warning
206 * config->gpio must be set to -EINVAL by platform code if
207 * GPIO control is not required. However, early adopters
208 * not requiring GPIO control may forget to initialize
209 * config->gpio to -EINVAL. This will cause GPIO 0 to be used
212 * This warning will be removed once there are a couple of users
217 "using GPIO 0 for regulator enable control\n");
219 ret = gpio_request(config->gpio, config->supply_name);
222 "Could not obtain regulator enable GPIO %d: %d\n",
227 /* set output direction without changing state
230 drvdata->is_enabled = config->enabled_at_boot;
231 ret = drvdata->is_enabled ?
232 config->enable_high : !config->enable_high;
234 ret = gpio_direction_output(config->gpio, ret);
237 "Could not configure regulator enable GPIO %d direction: %d\n",
243 /* Regulator without GPIO control is considered
246 drvdata->is_enabled = true;
249 drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
250 config->init_data, drvdata,
252 if (IS_ERR(drvdata->dev)) {
253 ret = PTR_ERR(drvdata->dev);
254 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
258 platform_set_drvdata(pdev, drvdata);
260 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
261 drvdata->microvolts);
266 if (gpio_is_valid(config->gpio))
267 gpio_free(config->gpio);
269 kfree(drvdata->desc.name);
275 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
277 struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
279 regulator_unregister(drvdata->dev);
280 if (gpio_is_valid(drvdata->gpio))
281 gpio_free(drvdata->gpio);
282 kfree(drvdata->desc.name);
288 #if defined(CONFIG_OF)
289 static const struct of_device_id fixed_of_match[] __devinitconst = {
290 { .compatible = "regulator-fixed", },
293 MODULE_DEVICE_TABLE(of, fixed_of_match);
295 #define fixed_of_match NULL
298 static struct platform_driver regulator_fixed_voltage_driver = {
299 .probe = reg_fixed_voltage_probe,
300 .remove = __devexit_p(reg_fixed_voltage_remove),
302 .name = "reg-fixed-voltage",
303 .owner = THIS_MODULE,
304 .of_match_table = fixed_of_match,
308 static int __init regulator_fixed_voltage_init(void)
310 return platform_driver_register(®ulator_fixed_voltage_driver);
312 subsys_initcall(regulator_fixed_voltage_init);
314 static void __exit regulator_fixed_voltage_exit(void)
316 platform_driver_unregister(®ulator_fixed_voltage_driver);
318 module_exit(regulator_fixed_voltage_exit);
320 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
321 MODULE_DESCRIPTION("Fixed voltage regulator");
322 MODULE_LICENSE("GPL");
323 MODULE_ALIAS("platform:reg-fixed-voltage");