1 /*
2  * userspace-consumer.c
3  *
4  * Copyright 2009 CompuLab, Ltd.
5  *
6  * Author: Mike Rapoport <mike@compulab.co.il>
7  *
8  * Based of virtual consumer driver:
9  *   Copyright 2008 Wolfson Microelectronics PLC.
10  *   Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
11  *
12  * This program is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU General Public License as
14  * published by the Free Software Foundation; either version 2 of the
15  * License, or (at your option) any later version.
16  *
17  */
18 
19 #include <linux/err.h>
20 #include <linux/mutex.h>
21 #include <linux/platform_device.h>
22 #include <linux/regulator/consumer.h>
23 #include <linux/regulator/userspace-consumer.h>
24 
25 struct userspace_consumer_data {
26 	const char *name;
27 
28 	struct mutex lock;
29 	bool enabled;
30 
31 	int num_supplies;
32 	struct regulator_bulk_data *supplies;
33 };
34 
35 static ssize_t reg_show_name(struct device *dev,
36 			  struct device_attribute *attr, char *buf)
37 {
38 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
39 
40 	return sprintf(buf, "%s\n", data->name);
41 }
42 
43 static ssize_t reg_show_state(struct device *dev,
44 			  struct device_attribute *attr, char *buf)
45 {
46 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
47 
48 	if (data->enabled)
49 		return sprintf(buf, "enabled\n");
50 
51 	return sprintf(buf, "disabled\n");
52 }
53 
54 static ssize_t reg_set_state(struct device *dev, struct device_attribute *attr,
55 			 const char *buf, size_t count)
56 {
57 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
58 	bool enabled;
59 	int ret;
60 
61 	/*
62 	 * sysfs_streq() doesn't need the \n's, but we add them so the strings
63 	 * will be shared with show_state(), above.
64 	 */
65 	if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
66 		enabled = true;
67 	else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
68 		enabled = false;
69 	else {
70 		dev_err(dev, "Configuring invalid mode\n");
71 		return count;
72 	}
73 
74 	mutex_lock(&data->lock);
75 	if (enabled != data->enabled) {
76 		if (enabled)
77 			ret = regulator_bulk_enable(data->num_supplies,
78 						    data->supplies);
79 		else
80 			ret = regulator_bulk_disable(data->num_supplies,
81 						     data->supplies);
82 
83 		if (ret == 0)
84 			data->enabled = enabled;
85 		else
86 			dev_err(dev, "Failed to configure state: %d\n", ret);
87 	}
88 	mutex_unlock(&data->lock);
89 
90 	return count;
91 }
92 
93 static DEVICE_ATTR(name, 0444, reg_show_name, NULL);
94 static DEVICE_ATTR(state, 0644, reg_show_state, reg_set_state);
95 
96 static struct attribute *attributes[] = {
97 	&dev_attr_name.attr,
98 	&dev_attr_state.attr,
99 	NULL,
100 };
101 
102 static const struct attribute_group attr_group = {
103 	.attrs	= attributes,
104 };
105 
106 static int regulator_userspace_consumer_probe(struct platform_device *pdev)
107 {
108 	struct regulator_userspace_consumer_data *pdata;
109 	struct userspace_consumer_data *drvdata;
110 	int ret;
111 
112 	pdata = pdev->dev.platform_data;
113 	if (!pdata)
114 		return -EINVAL;
115 
116 	drvdata = kzalloc(sizeof(struct userspace_consumer_data), GFP_KERNEL);
117 	if (drvdata == NULL)
118 		return -ENOMEM;
119 
120 	drvdata->name = pdata->name;
121 	drvdata->num_supplies = pdata->num_supplies;
122 	drvdata->supplies = pdata->supplies;
123 
124 	mutex_init(&drvdata->lock);
125 
126 	ret = regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
127 				 drvdata->supplies);
128 	if (ret) {
129 		dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
130 		goto err_alloc_supplies;
131 	}
132 
133 	ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
134 	if (ret != 0)
135 		goto err_create_attrs;
136 
137 	if (pdata->init_on) {
138 		ret = regulator_bulk_enable(drvdata->num_supplies,
139 					    drvdata->supplies);
140 		if (ret) {
141 			dev_err(&pdev->dev,
142 				"Failed to set initial state: %d\n", ret);
143 			goto err_enable;
144 		}
145 	}
146 
147 	drvdata->enabled = pdata->init_on;
148 	platform_set_drvdata(pdev, drvdata);
149 
150 	return 0;
151 
152 err_enable:
153 	sysfs_remove_group(&pdev->dev.kobj, &attr_group);
154 
155 err_create_attrs:
156 	regulator_bulk_free(drvdata->num_supplies, drvdata->supplies);
157 
158 err_alloc_supplies:
159 	kfree(drvdata);
160 	return ret;
161 }
162 
163 static int regulator_userspace_consumer_remove(struct platform_device *pdev)
164 {
165 	struct userspace_consumer_data *data = platform_get_drvdata(pdev);
166 
167 	sysfs_remove_group(&pdev->dev.kobj, &attr_group);
168 
169 	if (data->enabled)
170 		regulator_bulk_disable(data->num_supplies, data->supplies);
171 
172 	regulator_bulk_free(data->num_supplies, data->supplies);
173 	kfree(data);
174 
175 	return 0;
176 }
177 
178 static struct platform_driver regulator_userspace_consumer_driver = {
179 	.probe		= regulator_userspace_consumer_probe,
180 	.remove		= regulator_userspace_consumer_remove,
181 	.driver		= {
182 		.name		= "reg-userspace-consumer",
183 	},
184 };
185 
186 
187 static int __init regulator_userspace_consumer_init(void)
188 {
189 	return platform_driver_register(&regulator_userspace_consumer_driver);
190 }
191 module_init(regulator_userspace_consumer_init);
192 
193 static void __exit regulator_userspace_consumer_exit(void)
194 {
195 	platform_driver_unregister(&regulator_userspace_consumer_driver);
196 }
197 module_exit(regulator_userspace_consumer_exit);
198 
199 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
200 MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
201 MODULE_LICENSE("GPL");
202