aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/regulator/fixed.c
blob: f9f516a3028aa219a9dee0b397fc7e85fd54888d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
/*
 * fixed.c
 *
 * Copyright 2008 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 *
 * Copyright (c) 2009 Nokia Corporation
 * Roger Quadros <ext-roger.quadros@nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This is useful for systems with mixed controllable and
 * non-controllable regulators, as well as for allowing testing on
 * systems with no controllable regulators.
 */

#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/fixed.h>
#include <linux/gpio.h>

struct fixed_voltage_data {
	struct regulator_desc desc;
	struct regulator_dev *dev;
	int microvolts;
	int gpio;
	unsigned enable_high:1;
	unsigned is_enabled:1;
};

static int fixed_voltage_is_enabled(struct regulator_dev *dev)
{
	struct fixed_voltage_data *data = rdev_get_drvdata(dev);

	return data->is_enabled;
}

static int fixed_voltage_enable(struct regulator_dev *dev)
{
	struct fixed_voltage_data *data = rdev_get_drvdata(dev);

	if (gpio_is_valid(data->gpio)) {
		gpio_set_value_cansleep(data->gpio, data->enable_high);
		data->is_enabled = 1;
	}

	return 0;
}

static int fixed_voltage_disable(struct regulator_dev *dev)
{
	struct fixed_voltage_data *data = rdev_get_drvdata(dev);

	if (gpio_is_valid(data->gpio)) {
		gpio_set_value_cansleep(data->gpio, !data->enable_high);
		data->is_enabled = 0;
	}

	return 0;
}

static int fixed_voltage_get_voltage(struct regulator_dev *dev)
{
	struct fixed_voltage_data *data = rdev_get_drvdata(dev);

	return data->microvolts;
}

static int fixed_voltage_list_voltage(struct regulator_dev *dev,
				      unsigned selector)
{
	struct fixed_voltage_data *data = rdev_get_drvdata(dev);

	if (selector != 0)
		return -EINVAL;

	return data->microvolts;
}

static struct regulator_ops fixed_voltage_ops = {
	.is_enabled = fixed_voltage_is_enabled,
	.enable = fixed_voltage_enable,
	.disable = fixed_voltage_disable,
	.get_voltage = fixed_voltage_get_voltage,
	.list_voltage = fixed_voltage_list_voltage,
};

static int regulator_fixed_voltage_probe(struct platform_device *pdev)
{
	struct fixed_voltage_config *config = pdev->dev.platform_data;
	struct fixed_voltage_data *drvdata;
	int ret;

	drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
	if (drvdata == NULL) {
		dev_err(&pdev->dev, "Failed to allocate device data\n");
		ret = -ENOMEM;
		goto err;
	}

	drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
	if (drvdata->desc.name == NULL) {
		dev_err(&pdev->dev, "Failed to allocate supply name\n");
		ret = -ENOMEM;
		goto err;
	}
	drvdata->desc.type = REGULATOR_VOLTAGE;
	drvdata->desc.owner = THIS_MODULE;
	drvdata->desc.ops = &fixed_voltage_ops;
	drvdata->desc.n_voltages = 1;

	drvdata->microvolts = config->microvolts;
	drvdata->gpio = config->gpio;

	if (gpio_is_valid(config->gpio)) {
		drvdata->enable_high = config->enable_high;

		/* FIXME: Remove below print warning
		 *
		 * config->gpio must be set to -EINVAL by platform code if
		 * GPIO control is not required. However, early adopters
		 * not requiring GPIO control may forget to initialize
		 * config->gpio to -EINVAL. This will cause GPIO 0 to be used
		 * for GPIO control.
		 *
		 * This warning will be removed once there are a couple of users
		 * for this driver.
		 */
		if (!config->gpio)
			dev_warn(&pdev->dev,
				"using GPIO 0 for regulator enable control\n");

		ret = gpio_request(config->gpio, config->supply_name);
		if (ret) {
			dev_err(&pdev->dev,
			   "Could not obtain regulator enable GPIO %d: %d\n",
							config->gpio, ret);
			goto err_name;
		}

		/* set output direction without changing state
		 * to prevent glitch
		 */
		drvdata->is_enabled = config->enabled_at_boot;
		ret = drvdata->is_enabled ?
				config->enable_high : !config->enable_high;

		ret = gpio_direction_output(config->gpio, ret);
		if (ret) {
			dev_err(&pdev->dev,
			   "Could not configure regulator enable GPIO %d direction: %d\n",
							config->gpio, ret);
			goto err_gpio;
		}

	} else {
		/* Regulator without GPIO control is considered
		 * always enabled
		 */
		drvdata->is_enabled = 1;
	}

	drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
					  config->init_data, drvdata);
	if (IS_ERR(drvdata->dev)) {
		ret = PTR_ERR(drvdata->dev);
		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
		goto err_gpio;
	}

	platform_set_drvdata(pdev, drvdata);

	dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
		drvdata->microvolts);

	return 0;

err_gpio:
	if (gpio_is_valid(config->gpio))
		gpio_free(config->gpio);
err_name:
	kfree(drvdata->desc.name);
err:
	kfree(drvdata);
	return ret;
}

static int regulator_fixed_voltage_remove(struct platform_device *pdev)
{
	struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);

	regulator_unregister(drvdata->dev);
	if (gpio_is_valid(drvdata->gpio))
		gpio_free(drvdata->gpio);
	kfree(drvdata->desc.name);
	kfree(drvdata);

	return 0;
}

static struct platform_driver regulator_fixed_voltage_driver = {
	.probe		= regulator_fixed_voltage_probe,
	.remove		= regulator_fixed_voltage_remove,
	.driver		= {
		.name		= "reg-fixed-voltage",
	},
};

static int __init regulator_fixed_voltage_init(void)
{
	return platform_driver_register(&regulator_fixed_voltage_driver);
}
subsys_initcall(regulator_fixed_voltage_init);

static void __exit regulator_fixed_voltage_exit(void)
{
	platform_driver_unregister(&regulator_fixed_voltage_driver);
}
module_exit(regulator_fixed_voltage_exit);

MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("Fixed voltage regulator");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:reg-fixed-voltage");