1/*
2 * reg-virtual-consumer.c
3 *
4 * Copyright 2008 Wolfson Microelectronics PLC.
5 *
6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
12 */
13
14#include <linux/err.h>
15#include <linux/mutex.h>
16#include <linux/platform_device.h>
17#include <linux/regulator/consumer.h>
18#include <linux/slab.h>
19#include <linux/module.h>
20
21struct virtual_consumer_data {
22	struct mutex lock;
23	struct regulator *regulator;
24	bool enabled;
25	int min_uV;
26	int max_uV;
27	int min_uA;
28	int max_uA;
29	unsigned int mode;
30};
31
32static void update_voltage_constraints(struct device *dev,
33				       struct virtual_consumer_data *data)
34{
35	int ret;
36
37	if (data->min_uV && data->max_uV
38	    && data->min_uV <= data->max_uV) {
39		dev_dbg(dev, "Requesting %d-%duV\n",
40			data->min_uV, data->max_uV);
41		ret = regulator_set_voltage(data->regulator,
42					data->min_uV, data->max_uV);
43		if (ret != 0) {
44			dev_err(dev,
45				"regulator_set_voltage() failed: %d\n", ret);
46			return;
47		}
48	}
49
50	if (data->min_uV && data->max_uV && !data->enabled) {
51		dev_dbg(dev, "Enabling regulator\n");
52		ret = regulator_enable(data->regulator);
53		if (ret == 0)
54			data->enabled = true;
55		else
56			dev_err(dev, "regulator_enable() failed: %d\n",
57				ret);
58	}
59
60	if (!(data->min_uV && data->max_uV) && data->enabled) {
61		dev_dbg(dev, "Disabling regulator\n");
62		ret = regulator_disable(data->regulator);
63		if (ret == 0)
64			data->enabled = false;
65		else
66			dev_err(dev, "regulator_disable() failed: %d\n",
67				ret);
68	}
69}
70
71static void update_current_limit_constraints(struct device *dev,
72					  struct virtual_consumer_data *data)
73{
74	int ret;
75
76	if (data->max_uA
77	    && data->min_uA <= data->max_uA) {
78		dev_dbg(dev, "Requesting %d-%duA\n",
79			data->min_uA, data->max_uA);
80		ret = regulator_set_current_limit(data->regulator,
81					data->min_uA, data->max_uA);
82		if (ret != 0) {
83			dev_err(dev,
84				"regulator_set_current_limit() failed: %d\n",
85				ret);
86			return;
87		}
88	}
89
90	if (data->max_uA && !data->enabled) {
91		dev_dbg(dev, "Enabling regulator\n");
92		ret = regulator_enable(data->regulator);
93		if (ret == 0)
94			data->enabled = true;
95		else
96			dev_err(dev, "regulator_enable() failed: %d\n",
97				ret);
98	}
99
100	if (!(data->min_uA && data->max_uA) && data->enabled) {
101		dev_dbg(dev, "Disabling regulator\n");
102		ret = regulator_disable(data->regulator);
103		if (ret == 0)
104			data->enabled = false;
105		else
106			dev_err(dev, "regulator_disable() failed: %d\n",
107				ret);
108	}
109}
110
111static ssize_t show_min_uV(struct device *dev,
112			   struct device_attribute *attr, char *buf)
113{
114	struct virtual_consumer_data *data = dev_get_drvdata(dev);
115	return sprintf(buf, "%d\n", data->min_uV);
116}
117
118static ssize_t set_min_uV(struct device *dev, struct device_attribute *attr,
119			  const char *buf, size_t count)
120{
121	struct virtual_consumer_data *data = dev_get_drvdata(dev);
122	long val;
123
124	if (kstrtol(buf, 10, &val) != 0)
125		return count;
126
127	mutex_lock(&data->lock);
128
129	data->min_uV = val;
130	update_voltage_constraints(dev, data);
131
132	mutex_unlock(&data->lock);
133
134	return count;
135}
136
137static ssize_t show_max_uV(struct device *dev,
138			   struct device_attribute *attr, char *buf)
139{
140	struct virtual_consumer_data *data = dev_get_drvdata(dev);
141	return sprintf(buf, "%d\n", data->max_uV);
142}
143
144static ssize_t set_max_uV(struct device *dev, struct device_attribute *attr,
145			  const char *buf, size_t count)
146{
147	struct virtual_consumer_data *data = dev_get_drvdata(dev);
148	long val;
149
150	if (kstrtol(buf, 10, &val) != 0)
151		return count;
152
153	mutex_lock(&data->lock);
154
155	data->max_uV = val;
156	update_voltage_constraints(dev, data);
157
158	mutex_unlock(&data->lock);
159
160	return count;
161}
162
163static ssize_t show_min_uA(struct device *dev,
164			   struct device_attribute *attr, char *buf)
165{
166	struct virtual_consumer_data *data = dev_get_drvdata(dev);
167	return sprintf(buf, "%d\n", data->min_uA);
168}
169
170static ssize_t set_min_uA(struct device *dev, struct device_attribute *attr,
171			  const char *buf, size_t count)
172{
173	struct virtual_consumer_data *data = dev_get_drvdata(dev);
174	long val;
175
176	if (kstrtol(buf, 10, &val) != 0)
177		return count;
178
179	mutex_lock(&data->lock);
180
181	data->min_uA = val;
182	update_current_limit_constraints(dev, data);
183
184	mutex_unlock(&data->lock);
185
186	return count;
187}
188
189static ssize_t show_max_uA(struct device *dev,
190			   struct device_attribute *attr, char *buf)
191{
192	struct virtual_consumer_data *data = dev_get_drvdata(dev);
193	return sprintf(buf, "%d\n", data->max_uA);
194}
195
196static ssize_t set_max_uA(struct device *dev, struct device_attribute *attr,
197			  const char *buf, size_t count)
198{
199	struct virtual_consumer_data *data = dev_get_drvdata(dev);
200	long val;
201
202	if (kstrtol(buf, 10, &val) != 0)
203		return count;
204
205	mutex_lock(&data->lock);
206
207	data->max_uA = val;
208	update_current_limit_constraints(dev, data);
209
210	mutex_unlock(&data->lock);
211
212	return count;
213}
214
215static ssize_t show_mode(struct device *dev,
216			 struct device_attribute *attr, char *buf)
217{
218	struct virtual_consumer_data *data = dev_get_drvdata(dev);
219
220	switch (data->mode) {
221	case REGULATOR_MODE_FAST:
222		return sprintf(buf, "fast\n");
223	case REGULATOR_MODE_NORMAL:
224		return sprintf(buf, "normal\n");
225	case REGULATOR_MODE_IDLE:
226		return sprintf(buf, "idle\n");
227	case REGULATOR_MODE_STANDBY:
228		return sprintf(buf, "standby\n");
229	default:
230		return sprintf(buf, "unknown\n");
231	}
232}
233
234static ssize_t set_mode(struct device *dev, struct device_attribute *attr,
235			const char *buf, size_t count)
236{
237	struct virtual_consumer_data *data = dev_get_drvdata(dev);
238	unsigned int mode;
239	int ret;
240
241	/*
242	 * sysfs_streq() doesn't need the \n's, but we add them so the strings
243	 * will be shared with show_mode(), above.
244	 */
245	if (sysfs_streq(buf, "fast\n"))
246		mode = REGULATOR_MODE_FAST;
247	else if (sysfs_streq(buf, "normal\n"))
248		mode = REGULATOR_MODE_NORMAL;
249	else if (sysfs_streq(buf, "idle\n"))
250		mode = REGULATOR_MODE_IDLE;
251	else if (sysfs_streq(buf, "standby\n"))
252		mode = REGULATOR_MODE_STANDBY;
253	else {
254		dev_err(dev, "Configuring invalid mode\n");
255		return count;
256	}
257
258	mutex_lock(&data->lock);
259	ret = regulator_set_mode(data->regulator, mode);
260	if (ret == 0)
261		data->mode = mode;
262	else
263		dev_err(dev, "Failed to configure mode: %d\n", ret);
264	mutex_unlock(&data->lock);
265
266	return count;
267}
268
269static DEVICE_ATTR(min_microvolts, 0664, show_min_uV, set_min_uV);
270static DEVICE_ATTR(max_microvolts, 0664, show_max_uV, set_max_uV);
271static DEVICE_ATTR(min_microamps, 0664, show_min_uA, set_min_uA);
272static DEVICE_ATTR(max_microamps, 0664, show_max_uA, set_max_uA);
273static DEVICE_ATTR(mode, 0664, show_mode, set_mode);
274
275static struct attribute *regulator_virtual_attributes[] = {
276	&dev_attr_min_microvolts.attr,
277	&dev_attr_max_microvolts.attr,
278	&dev_attr_min_microamps.attr,
279	&dev_attr_max_microamps.attr,
280	&dev_attr_mode.attr,
281	NULL
282};
283
284static const struct attribute_group regulator_virtual_attr_group = {
285	.attrs	= regulator_virtual_attributes,
286};
287
288static int regulator_virtual_probe(struct platform_device *pdev)
289{
290	char *reg_id = dev_get_platdata(&pdev->dev);
291	struct virtual_consumer_data *drvdata;
292	int ret;
293
294	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct virtual_consumer_data),
295			       GFP_KERNEL);
296	if (drvdata == NULL)
297		return -ENOMEM;
298
299	mutex_init(&drvdata->lock);
300
301	drvdata->regulator = devm_regulator_get(&pdev->dev, reg_id);
302	if (IS_ERR(drvdata->regulator)) {
303		ret = PTR_ERR(drvdata->regulator);
304		dev_err(&pdev->dev, "Failed to obtain supply '%s': %d\n",
305			reg_id, ret);
306		return ret;
307	}
308
309	ret = sysfs_create_group(&pdev->dev.kobj,
310				 &regulator_virtual_attr_group);
311	if (ret != 0) {
312		dev_err(&pdev->dev,
313			"Failed to create attribute group: %d\n", ret);
314		return ret;
315	}
316
317	drvdata->mode = regulator_get_mode(drvdata->regulator);
318
319	platform_set_drvdata(pdev, drvdata);
320
321	return 0;
322}
323
324static int regulator_virtual_remove(struct platform_device *pdev)
325{
326	struct virtual_consumer_data *drvdata = platform_get_drvdata(pdev);
327
328	sysfs_remove_group(&pdev->dev.kobj, &regulator_virtual_attr_group);
329
330	if (drvdata->enabled)
331		regulator_disable(drvdata->regulator);
332
333	return 0;
334}
335
336static struct platform_driver regulator_virtual_consumer_driver = {
337	.probe		= regulator_virtual_probe,
338	.remove		= regulator_virtual_remove,
339	.driver		= {
340		.name		= "reg-virt-consumer",
341	},
342};
343
344module_platform_driver(regulator_virtual_consumer_driver);
345
346MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
347MODULE_DESCRIPTION("Virtual regulator consumer");
348MODULE_LICENSE("GPL");
349MODULE_ALIAS("platform:reg-virt-consumer");
350