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/regulator/driver.h>
22#include <linux/regulator/fixed.h>
23#include <linux/gpio/consumer.h>
24#include <linux/slab.h>
25#include <linux/of.h>
26#include <linux/of_device.h>
27#include <linux/regulator/of_regulator.h>
28#include <linux/regulator/machine.h>
29#include <linux/clk.h>
30
31
32struct fixed_voltage_data {
33	struct regulator_desc desc;
34	struct regulator_dev *dev;
35
36	struct clk *enable_clock;
37	unsigned int clk_enable_counter;
38};
39
40struct fixed_dev_type {
41	bool has_enable_clock;
42};
43
44static int reg_clock_enable(struct regulator_dev *rdev)
45{
46	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
47	int ret = 0;
48
49	ret = clk_prepare_enable(priv->enable_clock);
50	if (ret)
51		return ret;
52
53	priv->clk_enable_counter++;
54
55	return ret;
56}
57
58static int reg_clock_disable(struct regulator_dev *rdev)
59{
60	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
61
62	clk_disable_unprepare(priv->enable_clock);
63	priv->clk_enable_counter--;
64
65	return 0;
66}
67
68static int reg_clock_is_enabled(struct regulator_dev *rdev)
69{
70	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
71
72	return priv->clk_enable_counter > 0;
73}
74
75
76/**
77 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
78 * @dev: device requesting for fixed_voltage_config
79 * @desc: regulator description
80 *
81 * Populates fixed_voltage_config structure by extracting data from device
82 * tree node, returns a pointer to the populated structure of NULL if memory
83 * alloc fails.
84 */
85static struct fixed_voltage_config *
86of_get_fixed_voltage_config(struct device *dev,
87			    const struct regulator_desc *desc)
88{
89	struct fixed_voltage_config *config;
90	struct device_node *np = dev->of_node;
91	struct regulator_init_data *init_data;
92
93	config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
94								 GFP_KERNEL);
95	if (!config)
96		return ERR_PTR(-ENOMEM);
97
98	config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
99	if (!config->init_data)
100		return ERR_PTR(-EINVAL);
101
102	init_data = config->init_data;
103	init_data->constraints.apply_uV = 0;
104
105	config->supply_name = init_data->constraints.name;
106	if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
107		config->microvolts = init_data->constraints.min_uV;
108	} else {
109		dev_err(dev,
110			 "Fixed regulator specified with variable voltages\n");
111		return ERR_PTR(-EINVAL);
112	}
113
114	if (init_data->constraints.boot_on)
115		config->enabled_at_boot = true;
116
117	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
118	of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
119
120	if (of_find_property(np, "vin-supply", NULL))
121		config->input_supply = "vin";
122
123	return config;
124}
125
126static const struct regulator_ops fixed_voltage_ops = {
127};
128
129static const struct regulator_ops fixed_voltage_clkenabled_ops = {
130	.enable = reg_clock_enable,
131	.disable = reg_clock_disable,
132	.is_enabled = reg_clock_is_enabled,
133};
134
135static int reg_fixed_voltage_probe(struct platform_device *pdev)
136{
137	struct device *dev = &pdev->dev;
138	struct fixed_voltage_config *config;
139	struct fixed_voltage_data *drvdata;
140	const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
141	struct regulator_config cfg = { };
142	enum gpiod_flags gflags;
143	int ret;
144
145	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
146			       GFP_KERNEL);
147	if (!drvdata)
148		return -ENOMEM;
149
150	if (pdev->dev.of_node) {
151		config = of_get_fixed_voltage_config(&pdev->dev,
152						     &drvdata->desc);
153		if (IS_ERR(config))
154			return PTR_ERR(config);
155	} else {
156		config = dev_get_platdata(&pdev->dev);
157	}
158
159	if (!config)
160		return -ENOMEM;
161
162	drvdata->desc.name = devm_kstrdup(&pdev->dev,
163					  config->supply_name,
164					  GFP_KERNEL);
165	if (drvdata->desc.name == NULL) {
166		dev_err(&pdev->dev, "Failed to allocate supply name\n");
167		return -ENOMEM;
168	}
169	drvdata->desc.type = REGULATOR_VOLTAGE;
170	drvdata->desc.owner = THIS_MODULE;
171
172	if (drvtype && drvtype->has_enable_clock) {
173		drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
174
175		drvdata->enable_clock = devm_clk_get(dev, NULL);
176		if (IS_ERR(drvdata->enable_clock)) {
177			dev_err(dev, "Can't get enable-clock from devicetree\n");
178			return PTR_ERR(drvdata->enable_clock);
179		}
180	} else {
181		drvdata->desc.ops = &fixed_voltage_ops;
182	}
183
184	drvdata->desc.enable_time = config->startup_delay;
185	drvdata->desc.off_on_delay = config->off_on_delay;
186
187	if (config->input_supply) {
188		drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
189					    config->input_supply,
190					    GFP_KERNEL);
191		if (!drvdata->desc.supply_name) {
192			dev_err(&pdev->dev,
193				"Failed to allocate input supply\n");
194			return -ENOMEM;
195		}
196	}
197
198	if (config->microvolts)
199		drvdata->desc.n_voltages = 1;
200
201	drvdata->desc.fixed_uV = config->microvolts;
202
203	/*
204	 * The signal will be inverted by the GPIO core if flagged so in the
205	 * descriptor.
206	 */
207	if (config->enabled_at_boot)
208		gflags = GPIOD_OUT_HIGH;
209	else
210		gflags = GPIOD_OUT_LOW;
211
212	/*
213	 * Some fixed regulators share the enable line between two
214	 * regulators which makes it necessary to get a handle on the
215	 * same descriptor for two different consumers. This will get
216	 * the GPIO descriptor, but only the first call will initialize
217	 * it so any flags such as inversion or open drain will only
218	 * be set up by the first caller and assumed identical on the
219	 * next caller.
220	 *
221	 * FIXME: find a better way to deal with this.
222	 */
223	gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
224
225	/*
226	 * Do not use devm* here: the regulator core takes over the
227	 * lifecycle management of the GPIO descriptor.
228	 */
229	cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
230	if (IS_ERR(cfg.ena_gpiod))
231		return PTR_ERR(cfg.ena_gpiod);
232
233	cfg.dev = &pdev->dev;
234	cfg.init_data = config->init_data;
235	cfg.driver_data = drvdata;
236	cfg.of_node = pdev->dev.of_node;
237
238	drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
239					       &cfg);
240	if (IS_ERR(drvdata->dev)) {
241		ret = PTR_ERR(drvdata->dev);
242		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
243		return ret;
244	}
245
246	platform_set_drvdata(pdev, drvdata);
247
248	dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
249		drvdata->desc.fixed_uV);
250
251	return 0;
252}
253
254#if defined(CONFIG_OF)
255static const struct fixed_dev_type fixed_voltage_data = {
256	.has_enable_clock = false,
257};
258
259static const struct fixed_dev_type fixed_clkenable_data = {
260	.has_enable_clock = true,
261};
262
263static const struct of_device_id fixed_of_match[] = {
264	{
265		.compatible = "regulator-fixed",
266		.data = &fixed_voltage_data,
267	},
268	{
269		.compatible = "regulator-fixed-clock",
270		.data = &fixed_clkenable_data,
271	},
272	{
273	},
274};
275MODULE_DEVICE_TABLE(of, fixed_of_match);
276#endif
277
278static struct platform_driver regulator_fixed_voltage_driver = {
279	.probe		= reg_fixed_voltage_probe,
280	.driver		= {
281		.name		= "reg-fixed-voltage",
282		.of_match_table = of_match_ptr(fixed_of_match),
283	},
284};
285
286static int __init regulator_fixed_voltage_init(void)
287{
288	return platform_driver_register(&regulator_fixed_voltage_driver);
289}
290subsys_initcall(regulator_fixed_voltage_init);
291
292static void __exit regulator_fixed_voltage_exit(void)
293{
294	platform_driver_unregister(&regulator_fixed_voltage_driver);
295}
296module_exit(regulator_fixed_voltage_exit);
297
298MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
299MODULE_DESCRIPTION("Fixed voltage regulator");
300MODULE_LICENSE("GPL");
301MODULE_ALIAS("platform:reg-fixed-voltage");
302