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
23struct 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
34static 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
42static 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
53static 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
92static DEVICE_ATTR_RO(name);
93static DEVICE_ATTR_RW(state);
94
95static struct attribute *attributes[] = {
96	&dev_attr_name.attr,
97	&dev_attr_state.attr,
98	NULL,
99};
100
101static 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
113static const struct attribute_group attr_group = {
114	.attrs	= attributes,
115	.is_visible =  attr_visible,
116};
117
118static 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
191err_enable:
192	sysfs_remove_group(&pdev->dev.kobj, &attr_group);
193
194	return ret;
195}
196
197static void 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
207static const struct of_device_id regulator_userspace_consumer_of_match[] = {
208	{ .compatible = "regulator-output", },
209	{},
210};
211MODULE_DEVICE_TABLE(of, regulator_userspace_consumer_of_match);
212
213static struct platform_driver regulator_userspace_consumer_driver = {
214	.probe		= regulator_userspace_consumer_probe,
215	.remove_new	= regulator_userspace_consumer_remove,
216	.driver		= {
217		.name		= "reg-userspace-consumer",
218		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
219		.of_match_table	= regulator_userspace_consumer_of_match,
220	},
221};
222
223module_platform_driver(regulator_userspace_consumer_driver);
224
225MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
226MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
227MODULE_LICENSE("GPL");
228