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 int microvolts;
38 };
39
40
41 /**
42 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
43 * @dev: device requesting for fixed_voltage_config
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 *
of_get_fixed_voltage_config(struct device * dev)50 of_get_fixed_voltage_config(struct device *dev)
51 {
52 struct fixed_voltage_config *config;
53 struct device_node *np = dev->of_node;
54 const __be32 *delay;
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);
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 delay = of_get_property(np, "startup-delay-us", NULL);
96 if (delay)
97 config->startup_delay = be32_to_cpu(*delay);
98
99 if (of_find_property(np, "enable-active-high", NULL))
100 config->enable_high = true;
101
102 if (of_find_property(np, "gpio-open-drain", NULL))
103 config->gpio_is_open_drain = true;
104
105 if (of_find_property(np, "vin-supply", NULL))
106 config->input_supply = "vin";
107
108 return config;
109 }
110
fixed_voltage_get_voltage(struct regulator_dev * dev)111 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
112 {
113 struct fixed_voltage_data *data = rdev_get_drvdata(dev);
114
115 if (data->microvolts)
116 return data->microvolts;
117 else
118 return -EINVAL;
119 }
120
fixed_voltage_list_voltage(struct regulator_dev * dev,unsigned selector)121 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
122 unsigned selector)
123 {
124 struct fixed_voltage_data *data = rdev_get_drvdata(dev);
125
126 if (selector != 0)
127 return -EINVAL;
128
129 return data->microvolts;
130 }
131
132 static struct regulator_ops fixed_voltage_ops = {
133 .get_voltage = fixed_voltage_get_voltage,
134 .list_voltage = fixed_voltage_list_voltage,
135 };
136
reg_fixed_voltage_probe(struct platform_device * pdev)137 static int reg_fixed_voltage_probe(struct platform_device *pdev)
138 {
139 struct fixed_voltage_config *config;
140 struct fixed_voltage_data *drvdata;
141 struct regulator_config cfg = { };
142 int ret;
143
144 if (pdev->dev.of_node) {
145 config = of_get_fixed_voltage_config(&pdev->dev);
146 if (IS_ERR(config))
147 return PTR_ERR(config);
148 } else {
149 config = pdev->dev.platform_data;
150 }
151
152 if (!config)
153 return -ENOMEM;
154
155 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
156 GFP_KERNEL);
157 if (drvdata == NULL) {
158 dev_err(&pdev->dev, "Failed to allocate device data\n");
159 ret = -ENOMEM;
160 goto err;
161 }
162
163 drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
164 if (drvdata->desc.name == NULL) {
165 dev_err(&pdev->dev, "Failed to allocate supply name\n");
166 ret = -ENOMEM;
167 goto err;
168 }
169 drvdata->desc.type = REGULATOR_VOLTAGE;
170 drvdata->desc.owner = THIS_MODULE;
171 drvdata->desc.ops = &fixed_voltage_ops;
172
173 drvdata->desc.enable_time = config->startup_delay;
174
175 if (config->input_supply) {
176 drvdata->desc.supply_name = kstrdup(config->input_supply,
177 GFP_KERNEL);
178 if (!drvdata->desc.supply_name) {
179 dev_err(&pdev->dev,
180 "Failed to allocate input supply\n");
181 ret = -ENOMEM;
182 goto err_name;
183 }
184 }
185
186 if (config->microvolts)
187 drvdata->desc.n_voltages = 1;
188
189 drvdata->microvolts = config->microvolts;
190
191 if (config->gpio >= 0)
192 cfg.ena_gpio = config->gpio;
193 cfg.ena_gpio_invert = !config->enable_high;
194 if (config->enabled_at_boot) {
195 if (config->enable_high) {
196 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
197 } else {
198 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
199 }
200 } else {
201 if (config->enable_high) {
202 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
203 } else {
204 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
205 }
206 }
207 if (config->gpio_is_open_drain)
208 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
209
210 cfg.dev = &pdev->dev;
211 cfg.init_data = config->init_data;
212 cfg.driver_data = drvdata;
213 cfg.of_node = pdev->dev.of_node;
214
215 drvdata->dev = regulator_register(&drvdata->desc, &cfg);
216 if (IS_ERR(drvdata->dev)) {
217 ret = PTR_ERR(drvdata->dev);
218 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
219 goto err_input;
220 }
221
222 platform_set_drvdata(pdev, drvdata);
223
224 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
225 drvdata->microvolts);
226
227 return 0;
228
229 err_input:
230 kfree(drvdata->desc.supply_name);
231 err_name:
232 kfree(drvdata->desc.name);
233 err:
234 return ret;
235 }
236
reg_fixed_voltage_remove(struct platform_device * pdev)237 static int reg_fixed_voltage_remove(struct platform_device *pdev)
238 {
239 struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
240
241 regulator_unregister(drvdata->dev);
242 kfree(drvdata->desc.supply_name);
243 kfree(drvdata->desc.name);
244
245 return 0;
246 }
247
248 #if defined(CONFIG_OF)
249 static const struct of_device_id fixed_of_match[] = {
250 { .compatible = "regulator-fixed", },
251 {},
252 };
253 MODULE_DEVICE_TABLE(of, fixed_of_match);
254 #endif
255
256 static struct platform_driver regulator_fixed_voltage_driver = {
257 .probe = reg_fixed_voltage_probe,
258 .remove = reg_fixed_voltage_remove,
259 .driver = {
260 .name = "reg-fixed-voltage",
261 .owner = THIS_MODULE,
262 .of_match_table = of_match_ptr(fixed_of_match),
263 },
264 };
265
regulator_fixed_voltage_init(void)266 static int __init regulator_fixed_voltage_init(void)
267 {
268 return platform_driver_register(®ulator_fixed_voltage_driver);
269 }
270 subsys_initcall(regulator_fixed_voltage_init);
271
regulator_fixed_voltage_exit(void)272 static void __exit regulator_fixed_voltage_exit(void)
273 {
274 platform_driver_unregister(®ulator_fixed_voltage_driver);
275 }
276 module_exit(regulator_fixed_voltage_exit);
277
278 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
279 MODULE_DESCRIPTION("Fixed voltage regulator");
280 MODULE_LICENSE("GPL");
281 MODULE_ALIAS("platform:reg-fixed-voltage");
282