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