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 #include <linux/slab.h>
25 
26 struct userspace_consumer_data {
27 	const char *name;
28 
29 	struct mutex lock;
30 	bool enabled;
31 
32 	int num_supplies;
33 	struct regulator_bulk_data *supplies;
34 };
35 
36 static ssize_t reg_show_name(struct device *dev,
37 			  struct device_attribute *attr, char *buf)
38 {
39 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
40 
41 	return sprintf(buf, "%s\n", data->name);
42 }
43 
44 static ssize_t reg_show_state(struct device *dev,
45 			  struct device_attribute *attr, char *buf)
46 {
47 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
48 
49 	if (data->enabled)
50 		return sprintf(buf, "enabled\n");
51 
52 	return sprintf(buf, "disabled\n");
53 }
54 
55 static ssize_t reg_set_state(struct device *dev, struct device_attribute *attr,
56 			 const char *buf, size_t count)
57 {
58 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
59 	bool enabled;
60 	int ret;
61 
62 	/*
63 	 * sysfs_streq() doesn't need the \n's, but we add them so the strings
64 	 * will be shared with show_state(), above.
65 	 */
66 	if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
67 		enabled = true;
68 	else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
69 		enabled = false;
70 	else {
71 		dev_err(dev, "Configuring invalid mode\n");
72 		return count;
73 	}
74 
75 	mutex_lock(&data->lock);
76 	if (enabled != data->enabled) {
77 		if (enabled)
78 			ret = regulator_bulk_enable(data->num_supplies,
79 						    data->supplies);
80 		else
81 			ret = regulator_bulk_disable(data->num_supplies,
82 						     data->supplies);
83 
84 		if (ret == 0)
85 			data->enabled = enabled;
86 		else
87 			dev_err(dev, "Failed to configure state: %d\n", ret);
88 	}
89 	mutex_unlock(&data->lock);
90 
91 	return count;
92 }
93 
94 static DEVICE_ATTR(name, 0444, reg_show_name, NULL);
95 static DEVICE_ATTR(state, 0644, reg_show_state, reg_set_state);
96 
97 static struct attribute *attributes[] = {
98 	&dev_attr_name.attr,
99 	&dev_attr_state.attr,
100 	NULL,
101 };
102 
103 static const struct attribute_group attr_group = {
104 	.attrs	= attributes,
105 };
106 
107 static int regulator_userspace_consumer_probe(struct platform_device *pdev)
108 {
109 	struct regulator_userspace_consumer_data *pdata;
110 	struct userspace_consumer_data *drvdata;
111 	int ret;
112 
113 	pdata = pdev->dev.platform_data;
114 	if (!pdata)
115 		return -EINVAL;
116 
117 	drvdata = kzalloc(sizeof(struct userspace_consumer_data), GFP_KERNEL);
118 	if (drvdata == NULL)
119 		return -ENOMEM;
120 
121 	drvdata->name = pdata->name;
122 	drvdata->num_supplies = pdata->num_supplies;
123 	drvdata->supplies = pdata->supplies;
124 
125 	mutex_init(&drvdata->lock);
126 
127 	ret = regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
128 				 drvdata->supplies);
129 	if (ret) {
130 		dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
131 		goto err_alloc_supplies;
132 	}
133 
134 	ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
135 	if (ret != 0)
136 		goto err_create_attrs;
137 
138 	if (pdata->init_on) {
139 		ret = regulator_bulk_enable(drvdata->num_supplies,
140 					    drvdata->supplies);
141 		if (ret) {
142 			dev_err(&pdev->dev,
143 				"Failed to set initial state: %d\n", ret);
144 			goto err_enable;
145 		}
146 	}
147 
148 	drvdata->enabled = pdata->init_on;
149 	platform_set_drvdata(pdev, drvdata);
150 
151 	return 0;
152 
153 err_enable:
154 	sysfs_remove_group(&pdev->dev.kobj, &attr_group);
155 
156 err_create_attrs:
157 	regulator_bulk_free(drvdata->num_supplies, drvdata->supplies);
158 
159 err_alloc_supplies:
160 	kfree(drvdata);
161 	return ret;
162 }
163 
164 static int regulator_userspace_consumer_remove(struct platform_device *pdev)
165 {
166 	struct userspace_consumer_data *data = platform_get_drvdata(pdev);
167 
168 	sysfs_remove_group(&pdev->dev.kobj, &attr_group);
169 
170 	if (data->enabled)
171 		regulator_bulk_disable(data->num_supplies, data->supplies);
172 
173 	regulator_bulk_free(data->num_supplies, data->supplies);
174 	kfree(data);
175 
176 	return 0;
177 }
178 
179 static struct platform_driver regulator_userspace_consumer_driver = {
180 	.probe		= regulator_userspace_consumer_probe,
181 	.remove		= regulator_userspace_consumer_remove,
182 	.driver		= {
183 		.name		= "reg-userspace-consumer",
184 	},
185 };
186 
187 
188 static int __init regulator_userspace_consumer_init(void)
189 {
190 	return platform_driver_register(&regulator_userspace_consumer_driver);
191 }
192 module_init(regulator_userspace_consumer_init);
193 
194 static void __exit regulator_userspace_consumer_exit(void)
195 {
196 	platform_driver_unregister(&regulator_userspace_consumer_driver);
197 }
198 module_exit(regulator_userspace_consumer_exit);
199 
200 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
201 MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
202 MODULE_LICENSE("GPL");
203