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/of.h>
18 #include <linux/platform_device.h>
19 #include <linux/regulator/consumer.h>
20 #include <linux/regulator/userspace-consumer.h>
21 #include <linux/slab.h>
22 
23 struct userspace_consumer_data {
24 	const char *name;
25 
26 	struct mutex lock;
27 	bool enabled;
28 	bool no_autoswitch;
29 
30 	int num_supplies;
31 	struct regulator_bulk_data *supplies;
32 };
33 
34 static ssize_t name_show(struct device *dev,
35 			 struct device_attribute *attr, char *buf)
36 {
37 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
38 
39 	return sprintf(buf, "%s\n", data->name);
40 }
41 
42 static ssize_t state_show(struct device *dev,
43 			  struct device_attribute *attr, char *buf)
44 {
45 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
46 
47 	if (data->enabled)
48 		return sprintf(buf, "enabled\n");
49 
50 	return sprintf(buf, "disabled\n");
51 }
52 
53 static ssize_t state_store(struct device *dev, struct device_attribute *attr,
54 			   const char *buf, size_t count)
55 {
56 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
57 	bool enabled;
58 	int ret;
59 
60 	/*
61 	 * sysfs_streq() doesn't need the \n's, but we add them so the strings
62 	 * will be shared with show_state(), above.
63 	 */
64 	if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
65 		enabled = true;
66 	else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
67 		enabled = false;
68 	else {
69 		dev_err(dev, "Configuring invalid mode\n");
70 		return count;
71 	}
72 
73 	mutex_lock(&data->lock);
74 	if (enabled != data->enabled) {
75 		if (enabled)
76 			ret = regulator_bulk_enable(data->num_supplies,
77 						    data->supplies);
78 		else
79 			ret = regulator_bulk_disable(data->num_supplies,
80 						     data->supplies);
81 
82 		if (ret == 0)
83 			data->enabled = enabled;
84 		else
85 			dev_err(dev, "Failed to configure state: %d\n", ret);
86 	}
87 	mutex_unlock(&data->lock);
88 
89 	return count;
90 }
91 
92 static DEVICE_ATTR_RO(name);
93 static DEVICE_ATTR_RW(state);
94 
95 static struct attribute *attributes[] = {
96 	&dev_attr_name.attr,
97 	&dev_attr_state.attr,
98 	NULL,
99 };
100 
101 static umode_t attr_visible(struct kobject *kobj, struct attribute *attr, int idx)
102 {
103 	struct device *dev = kobj_to_dev(kobj);
104 	struct userspace_consumer_data *data = dev_get_drvdata(dev);
105 
106 	/* If a name hasn't been set, don't bother with the attribute */
107 	if (attr == &dev_attr_name.attr && !data->name)
108 		return 0;
109 
110 	return attr->mode;
111 }
112 
113 static const struct attribute_group attr_group = {
114 	.attrs	= attributes,
115 	.is_visible =  attr_visible,
116 };
117 
118 static int regulator_userspace_consumer_probe(struct platform_device *pdev)
119 {
120 	struct regulator_userspace_consumer_data tmpdata;
121 	struct regulator_userspace_consumer_data *pdata;
122 	struct userspace_consumer_data *drvdata;
123 	int ret;
124 
125 	pdata = dev_get_platdata(&pdev->dev);
126 	if (!pdata) {
127 		if (!pdev->dev.of_node)
128 			return -EINVAL;
129 
130 		pdata = &tmpdata;
131 		memset(pdata, 0, sizeof(*pdata));
132 
133 		pdata->no_autoswitch = true;
134 		pdata->num_supplies = 1;
135 		pdata->supplies = devm_kzalloc(&pdev->dev, sizeof(*pdata->supplies), GFP_KERNEL);
136 		if (!pdata->supplies)
137 			return -ENOMEM;
138 		pdata->supplies[0].supply = "vout";
139 	}
140 
141 	if (pdata->num_supplies < 1) {
142 		dev_err(&pdev->dev, "At least one supply required\n");
143 		return -EINVAL;
144 	}
145 
146 	drvdata = devm_kzalloc(&pdev->dev,
147 			       sizeof(struct userspace_consumer_data),
148 			       GFP_KERNEL);
149 	if (drvdata == NULL)
150 		return -ENOMEM;
151 
152 	drvdata->name = pdata->name;
153 	drvdata->num_supplies = pdata->num_supplies;
154 	drvdata->supplies = pdata->supplies;
155 	drvdata->no_autoswitch = pdata->no_autoswitch;
156 
157 	mutex_init(&drvdata->lock);
158 
159 	ret = devm_regulator_bulk_get_exclusive(&pdev->dev, drvdata->num_supplies,
160 						drvdata->supplies);
161 	if (ret) {
162 		dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
163 		return ret;
164 	}
165 
166 	platform_set_drvdata(pdev, drvdata);
167 
168 	ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
169 	if (ret != 0)
170 		return ret;
171 
172 	if (pdata->init_on && !pdata->no_autoswitch) {
173 		ret = regulator_bulk_enable(drvdata->num_supplies,
174 					    drvdata->supplies);
175 		if (ret) {
176 			dev_err(&pdev->dev,
177 				"Failed to set initial state: %d\n", ret);
178 			goto err_enable;
179 		}
180 	}
181 
182 	ret = regulator_is_enabled(pdata->supplies[0].consumer);
183 	if (ret < 0) {
184 		dev_err(&pdev->dev, "Failed to get regulator status\n");
185 		goto err_enable;
186 	}
187 	drvdata->enabled = !!ret;
188 
189 	return 0;
190 
191 err_enable:
192 	sysfs_remove_group(&pdev->dev.kobj, &attr_group);
193 
194 	return ret;
195 }
196 
197 static int regulator_userspace_consumer_remove(struct platform_device *pdev)
198 {
199 	struct userspace_consumer_data *data = platform_get_drvdata(pdev);
200 
201 	sysfs_remove_group(&pdev->dev.kobj, &attr_group);
202 
203 	if (data->enabled && !data->no_autoswitch)
204 		regulator_bulk_disable(data->num_supplies, data->supplies);
205 
206 	return 0;
207 }
208 
209 static const struct of_device_id regulator_userspace_consumer_of_match[] = {
210 	{ .compatible = "regulator-output", },
211 	{},
212 };
213 
214 static struct platform_driver regulator_userspace_consumer_driver = {
215 	.probe		= regulator_userspace_consumer_probe,
216 	.remove		= regulator_userspace_consumer_remove,
217 	.driver		= {
218 		.name		= "reg-userspace-consumer",
219 		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
220 		.of_match_table	= regulator_userspace_consumer_of_match,
221 	},
222 };
223 
224 module_platform_driver(regulator_userspace_consumer_driver);
225 
226 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
227 MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
228 MODULE_LICENSE("GPL");
229