1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * fixed.c
4 *
5 * Copyright 2008 Wolfson Microelectronics PLC.
6 *
7 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
8 *
9 * Copyright (c) 2009 Nokia Corporation
10 * Roger Quadros <ext-roger.quadros@nokia.com>
11 *
12 * This is useful for systems with mixed controllable and
13 * non-controllable regulators, as well as for allowing testing on
14 * systems with no controllable regulators.
15 */
16
17#include <linux/err.h>
18#include <linux/mutex.h>
19#include <linux/module.h>
20#include <linux/platform_device.h>
21#include <linux/pm_domain.h>
22#include <linux/pm_opp.h>
23#include <linux/regulator/driver.h>
24#include <linux/regulator/fixed.h>
25#include <linux/gpio/consumer.h>
26#include <linux/slab.h>
27#include <linux/of.h>
28#include <linux/regulator/of_regulator.h>
29#include <linux/regulator/machine.h>
30#include <linux/clk.h>
31
32
33struct fixed_voltage_data {
34	struct regulator_desc desc;
35	struct regulator_dev *dev;
36
37	struct clk *enable_clock;
38	unsigned int enable_counter;
39	int performance_state;
40};
41
42struct fixed_dev_type {
43	bool has_enable_clock;
44	bool has_performance_state;
45};
46
47static int reg_clock_enable(struct regulator_dev *rdev)
48{
49	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
50	int ret = 0;
51
52	ret = clk_prepare_enable(priv->enable_clock);
53	if (ret)
54		return ret;
55
56	priv->enable_counter++;
57
58	return ret;
59}
60
61static int reg_clock_disable(struct regulator_dev *rdev)
62{
63	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
64
65	clk_disable_unprepare(priv->enable_clock);
66	priv->enable_counter--;
67
68	return 0;
69}
70
71static int reg_domain_enable(struct regulator_dev *rdev)
72{
73	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
74	struct device *dev = rdev->dev.parent;
75	int ret;
76
77	ret = dev_pm_genpd_set_performance_state(dev, priv->performance_state);
78	if (ret)
79		return ret;
80
81	priv->enable_counter++;
82
83	return ret;
84}
85
86static int reg_domain_disable(struct regulator_dev *rdev)
87{
88	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
89	struct device *dev = rdev->dev.parent;
90	int ret;
91
92	ret = dev_pm_genpd_set_performance_state(dev, 0);
93	if (ret)
94		return ret;
95
96	priv->enable_counter--;
97
98	return 0;
99}
100
101static int reg_is_enabled(struct regulator_dev *rdev)
102{
103	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
104
105	return priv->enable_counter > 0;
106}
107
108
109/**
110 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
111 * @dev: device requesting for fixed_voltage_config
112 * @desc: regulator description
113 *
114 * Populates fixed_voltage_config structure by extracting data from device
115 * tree node, returns a pointer to the populated structure of NULL if memory
116 * alloc fails.
117 */
118static struct fixed_voltage_config *
119of_get_fixed_voltage_config(struct device *dev,
120			    const struct regulator_desc *desc)
121{
122	struct fixed_voltage_config *config;
123	struct device_node *np = dev->of_node;
124	struct regulator_init_data *init_data;
125
126	config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
127								 GFP_KERNEL);
128	if (!config)
129		return ERR_PTR(-ENOMEM);
130
131	config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
132	if (!config->init_data)
133		return ERR_PTR(-EINVAL);
134
135	init_data = config->init_data;
136	init_data->constraints.apply_uV = 0;
137
138	config->supply_name = init_data->constraints.name;
139	if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
140		config->microvolts = init_data->constraints.min_uV;
141	} else {
142		dev_err(dev,
143			 "Fixed regulator specified with variable voltages\n");
144		return ERR_PTR(-EINVAL);
145	}
146
147	if (init_data->constraints.boot_on)
148		config->enabled_at_boot = true;
149
150	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
151	of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
152
153	if (of_property_present(np, "vin-supply"))
154		config->input_supply = "vin";
155
156	return config;
157}
158
159static const struct regulator_ops fixed_voltage_ops = {
160};
161
162static const struct regulator_ops fixed_voltage_clkenabled_ops = {
163	.enable = reg_clock_enable,
164	.disable = reg_clock_disable,
165	.is_enabled = reg_is_enabled,
166};
167
168static const struct regulator_ops fixed_voltage_domain_ops = {
169	.enable = reg_domain_enable,
170	.disable = reg_domain_disable,
171	.is_enabled = reg_is_enabled,
172};
173
174static int reg_fixed_voltage_probe(struct platform_device *pdev)
175{
176	struct device *dev = &pdev->dev;
177	struct fixed_voltage_config *config;
178	struct fixed_voltage_data *drvdata;
179	const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
180	struct regulator_config cfg = { };
181	enum gpiod_flags gflags;
182	int ret;
183
184	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
185			       GFP_KERNEL);
186	if (!drvdata)
187		return -ENOMEM;
188
189	if (pdev->dev.of_node) {
190		config = of_get_fixed_voltage_config(&pdev->dev,
191						     &drvdata->desc);
192		if (IS_ERR(config))
193			return PTR_ERR(config);
194	} else {
195		config = dev_get_platdata(&pdev->dev);
196	}
197
198	if (!config)
199		return -ENOMEM;
200
201	drvdata->desc.name = devm_kstrdup(&pdev->dev,
202					  config->supply_name,
203					  GFP_KERNEL);
204	if (drvdata->desc.name == NULL) {
205		dev_err(&pdev->dev, "Failed to allocate supply name\n");
206		return -ENOMEM;
207	}
208	drvdata->desc.type = REGULATOR_VOLTAGE;
209	drvdata->desc.owner = THIS_MODULE;
210
211	if (drvtype && drvtype->has_enable_clock) {
212		drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
213
214		drvdata->enable_clock = devm_clk_get(dev, NULL);
215		if (IS_ERR(drvdata->enable_clock)) {
216			dev_err(dev, "Can't get enable-clock from devicetree\n");
217			return PTR_ERR(drvdata->enable_clock);
218		}
219	} else if (drvtype && drvtype->has_performance_state) {
220		drvdata->desc.ops = &fixed_voltage_domain_ops;
221
222		drvdata->performance_state = of_get_required_opp_performance_state(dev->of_node, 0);
223		if (drvdata->performance_state < 0) {
224			dev_err(dev, "Can't get performance state from devicetree\n");
225			return drvdata->performance_state;
226		}
227	} else {
228		drvdata->desc.ops = &fixed_voltage_ops;
229	}
230
231	drvdata->desc.enable_time = config->startup_delay;
232	drvdata->desc.off_on_delay = config->off_on_delay;
233
234	if (config->input_supply) {
235		drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
236					    config->input_supply,
237					    GFP_KERNEL);
238		if (!drvdata->desc.supply_name)
239			return -ENOMEM;
240	}
241
242	if (config->microvolts)
243		drvdata->desc.n_voltages = 1;
244
245	drvdata->desc.fixed_uV = config->microvolts;
246
247	/*
248	 * The signal will be inverted by the GPIO core if flagged so in the
249	 * descriptor.
250	 */
251	if (config->enabled_at_boot)
252		gflags = GPIOD_OUT_HIGH;
253	else
254		gflags = GPIOD_OUT_LOW;
255
256	/*
257	 * Some fixed regulators share the enable line between two
258	 * regulators which makes it necessary to get a handle on the
259	 * same descriptor for two different consumers. This will get
260	 * the GPIO descriptor, but only the first call will initialize
261	 * it so any flags such as inversion or open drain will only
262	 * be set up by the first caller and assumed identical on the
263	 * next caller.
264	 *
265	 * FIXME: find a better way to deal with this.
266	 */
267	gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
268
269	/*
270	 * Do not use devm* here: the regulator core takes over the
271	 * lifecycle management of the GPIO descriptor.
272	 */
273	cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
274	if (IS_ERR(cfg.ena_gpiod))
275		return dev_err_probe(&pdev->dev, PTR_ERR(cfg.ena_gpiod),
276				     "can't get GPIO\n");
277
278	cfg.dev = &pdev->dev;
279	cfg.init_data = config->init_data;
280	cfg.driver_data = drvdata;
281	cfg.of_node = pdev->dev.of_node;
282
283	drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
284					       &cfg);
285	if (IS_ERR(drvdata->dev)) {
286		ret = dev_err_probe(&pdev->dev, PTR_ERR(drvdata->dev),
287				    "Failed to register regulator: %ld\n",
288				    PTR_ERR(drvdata->dev));
289		return ret;
290	}
291
292	platform_set_drvdata(pdev, drvdata);
293
294	dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
295		drvdata->desc.fixed_uV);
296
297	return 0;
298}
299
300#if defined(CONFIG_OF)
301static const struct fixed_dev_type fixed_voltage_data = {
302	.has_enable_clock = false,
303};
304
305static const struct fixed_dev_type fixed_clkenable_data = {
306	.has_enable_clock = true,
307};
308
309static const struct fixed_dev_type fixed_domain_data = {
310	.has_performance_state = true,
311};
312
313static const struct of_device_id fixed_of_match[] = {
314	{
315		.compatible = "regulator-fixed",
316		.data = &fixed_voltage_data,
317	},
318	{
319		.compatible = "regulator-fixed-clock",
320		.data = &fixed_clkenable_data,
321	},
322	{
323		.compatible = "regulator-fixed-domain",
324		.data = &fixed_domain_data,
325	},
326	{
327	},
328};
329MODULE_DEVICE_TABLE(of, fixed_of_match);
330#endif
331
332static struct platform_driver regulator_fixed_voltage_driver = {
333	.probe		= reg_fixed_voltage_probe,
334	.driver		= {
335		.name		= "reg-fixed-voltage",
336		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
337		.of_match_table = of_match_ptr(fixed_of_match),
338	},
339};
340
341static int __init regulator_fixed_voltage_init(void)
342{
343	return platform_driver_register(&regulator_fixed_voltage_driver);
344}
345subsys_initcall(regulator_fixed_voltage_init);
346
347static void __exit regulator_fixed_voltage_exit(void)
348{
349	platform_driver_unregister(&regulator_fixed_voltage_driver);
350}
351module_exit(regulator_fixed_voltage_exit);
352
353MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
354MODULE_DESCRIPTION("Fixed voltage regulator");
355MODULE_LICENSE("GPL");
356MODULE_ALIAS("platform:reg-fixed-voltage");
357