1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * userspace-consumer.c
4  *
5  * Copyright 2009 CompuLab, Ltd.
6  *
7  * Author: Mike Rapoport <mike@compulab.co.il>
8  *
9  * Based of virtual consumer driver:
10  *   Copyright 2008 Wolfson Microelectronics PLC.
11  *   Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
12  */
13 
14 #include <linux/err.h>
15 #include <linux/mutex.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/regulator/consumer.h>
19 #include <linux/regulator/userspace-consumer.h>
20 #include <linux/slab.h>
21 
22 struct userspace_consumer_data {
23 	const char *name;
24 
25 	struct mutex lock;
26 	bool enabled;
27 
28 	int num_supplies;
29 	struct regulator_bulk_data *supplies;
30 };
31 
32 static ssize_t name_show(struct device *dev,
33 			 struct device_attribute *attr, char *buf)
34 {
35 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
36 
37 	return sprintf(buf, "%s\n", data->name);
38 }
39 
40 static ssize_t state_show(struct device *dev,
41 			  struct device_attribute *attr, char *buf)
42 {
43 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
44 
45 	if (data->enabled)
46 		return sprintf(buf, "enabled\n");
47 
48 	return sprintf(buf, "disabled\n");
49 }
50 
51 static ssize_t state_store(struct device *dev, struct device_attribute *attr,
52 			   const char *buf, size_t count)
53 {
54 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
55 	bool enabled;
56 	int ret;
57 
58 	/*
59 	 * sysfs_streq() doesn't need the \n's, but we add them so the strings
60 	 * will be shared with show_state(), above.
61 	 */
62 	if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
63 		enabled = true;
64 	else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
65 		enabled = false;
66 	else {
67 		dev_err(dev, "Configuring invalid mode\n");
68 		return count;
69 	}
70 
71 	mutex_lock(&data->lock);
72 	if (enabled != data->enabled) {
73 		if (enabled)
74 			ret = regulator_bulk_enable(data->num_supplies,
75 						    data->supplies);
76 		else
77 			ret = regulator_bulk_disable(data->num_supplies,
78 						     data->supplies);
79 
80 		if (ret == 0)
81 			data->enabled = enabled;
82 		else
83 			dev_err(dev, "Failed to configure state: %d\n", ret);
84 	}
85 	mutex_unlock(&data->lock);
86 
87 	return count;
88 }
89 
90 static DEVICE_ATTR_RO(name);
91 static DEVICE_ATTR_RW(state);
92 
93 static struct attribute *attributes[] = {
94 	&dev_attr_name.attr,
95 	&dev_attr_state.attr,
96 	NULL,
97 };
98 
99 static const struct attribute_group attr_group = {
100 	.attrs	= attributes,
101 };
102 
103 static int regulator_userspace_consumer_probe(struct platform_device *pdev)
104 {
105 	struct regulator_userspace_consumer_data *pdata;
106 	struct userspace_consumer_data *drvdata;
107 	int ret;
108 
109 	pdata = dev_get_platdata(&pdev->dev);
110 	if (!pdata)
111 		return -EINVAL;
112 
113 	drvdata = devm_kzalloc(&pdev->dev,
114 			       sizeof(struct userspace_consumer_data),
115 			       GFP_KERNEL);
116 	if (drvdata == NULL)
117 		return -ENOMEM;
118 
119 	drvdata->name = pdata->name;
120 	drvdata->num_supplies = pdata->num_supplies;
121 	drvdata->supplies = pdata->supplies;
122 
123 	mutex_init(&drvdata->lock);
124 
125 	ret = devm_regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
126 				      drvdata->supplies);
127 	if (ret) {
128 		dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
129 		return ret;
130 	}
131 
132 	ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
133 	if (ret != 0)
134 		return ret;
135 
136 	if (pdata->init_on) {
137 		ret = regulator_bulk_enable(drvdata->num_supplies,
138 					    drvdata->supplies);
139 		if (ret) {
140 			dev_err(&pdev->dev,
141 				"Failed to set initial state: %d\n", ret);
142 			goto err_enable;
143 		}
144 	}
145 
146 	drvdata->enabled = pdata->init_on;
147 	platform_set_drvdata(pdev, drvdata);
148 
149 	return 0;
150 
151 err_enable:
152 	sysfs_remove_group(&pdev->dev.kobj, &attr_group);
153 
154 	return ret;
155 }
156 
157 static int regulator_userspace_consumer_remove(struct platform_device *pdev)
158 {
159 	struct userspace_consumer_data *data = platform_get_drvdata(pdev);
160 
161 	sysfs_remove_group(&pdev->dev.kobj, &attr_group);
162 
163 	if (data->enabled)
164 		regulator_bulk_disable(data->num_supplies, data->supplies);
165 
166 	return 0;
167 }
168 
169 static struct platform_driver regulator_userspace_consumer_driver = {
170 	.probe		= regulator_userspace_consumer_probe,
171 	.remove		= regulator_userspace_consumer_remove,
172 	.driver		= {
173 		.name		= "reg-userspace-consumer",
174 	},
175 };
176 
177 module_platform_driver(regulator_userspace_consumer_driver);
178 
179 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
180 MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
181 MODULE_LICENSE("GPL");
182