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/reboot.h>
24#include <linux/regulator/driver.h>
25#include <linux/regulator/fixed.h>
26#include <linux/gpio/consumer.h>
27#include <linux/slab.h>
28#include <linux/of.h>
29#include <linux/regulator/of_regulator.h>
30#include <linux/regulator/machine.h>
31#include <linux/clk.h>
32
33/* Default time in millisecond to wait for emergency shutdown */
34#define FV_DEF_EMERG_SHUTDWN_TMO	10
35
36struct fixed_voltage_data {
37	struct regulator_desc desc;
38	struct regulator_dev *dev;
39
40	struct clk *enable_clock;
41	unsigned int enable_counter;
42	int performance_state;
43};
44
45struct fixed_dev_type {
46	bool has_enable_clock;
47	bool has_performance_state;
48};
49
50static int reg_clock_enable(struct regulator_dev *rdev)
51{
52	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
53	int ret = 0;
54
55	ret = clk_prepare_enable(priv->enable_clock);
56	if (ret)
57		return ret;
58
59	priv->enable_counter++;
60
61	return ret;
62}
63
64static int reg_clock_disable(struct regulator_dev *rdev)
65{
66	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
67
68	clk_disable_unprepare(priv->enable_clock);
69	priv->enable_counter--;
70
71	return 0;
72}
73
74static int reg_domain_enable(struct regulator_dev *rdev)
75{
76	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
77	struct device *dev = rdev->dev.parent;
78	int ret;
79
80	ret = dev_pm_genpd_set_performance_state(dev, priv->performance_state);
81	if (ret)
82		return ret;
83
84	priv->enable_counter++;
85
86	return ret;
87}
88
89static int reg_domain_disable(struct regulator_dev *rdev)
90{
91	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
92	struct device *dev = rdev->dev.parent;
93	int ret;
94
95	ret = dev_pm_genpd_set_performance_state(dev, 0);
96	if (ret)
97		return ret;
98
99	priv->enable_counter--;
100
101	return 0;
102}
103
104static int reg_is_enabled(struct regulator_dev *rdev)
105{
106	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
107
108	return priv->enable_counter > 0;
109}
110
111static irqreturn_t reg_fixed_under_voltage_irq_handler(int irq, void *data)
112{
113	struct fixed_voltage_data *priv = data;
114	struct regulator_dev *rdev = priv->dev;
115
116	regulator_notifier_call_chain(rdev, REGULATOR_EVENT_UNDER_VOLTAGE,
117				      NULL);
118
119	return IRQ_HANDLED;
120}
121
122/**
123 * reg_fixed_get_irqs - Get and register the optional IRQ for fixed voltage
124 *                      regulator.
125 * @dev: Pointer to the device structure.
126 * @priv: Pointer to fixed_voltage_data structure containing private data.
127 *
128 * This function tries to get the IRQ from the device firmware node.
129 * If it's an optional IRQ and not found, it returns 0.
130 * Otherwise, it attempts to request the threaded IRQ.
131 *
132 * Return: 0 on success, or error code on failure.
133 */
134static int reg_fixed_get_irqs(struct device *dev,
135			      struct fixed_voltage_data *priv)
136{
137	int ret;
138
139	ret = fwnode_irq_get(dev_fwnode(dev), 0);
140	/* This is optional IRQ. If not found we will get -EINVAL */
141	if (ret == -EINVAL)
142		return 0;
143	if (ret < 0)
144		return dev_err_probe(dev, ret, "Failed to get IRQ\n");
145
146	ret = devm_request_threaded_irq(dev, ret, NULL,
147					reg_fixed_under_voltage_irq_handler,
148					IRQF_ONESHOT, "under-voltage", priv);
149	if (ret)
150		return dev_err_probe(dev, ret, "Failed to request IRQ\n");
151
152	return 0;
153}
154
155/**
156 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
157 * @dev: device requesting for fixed_voltage_config
158 * @desc: regulator description
159 *
160 * Populates fixed_voltage_config structure by extracting data from device
161 * tree node, returns a pointer to the populated structure of NULL if memory
162 * alloc fails.
163 */
164static struct fixed_voltage_config *
165of_get_fixed_voltage_config(struct device *dev,
166			    const struct regulator_desc *desc)
167{
168	struct fixed_voltage_config *config;
169	struct device_node *np = dev->of_node;
170	struct regulator_init_data *init_data;
171
172	config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
173								 GFP_KERNEL);
174	if (!config)
175		return ERR_PTR(-ENOMEM);
176
177	config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
178	if (!config->init_data)
179		return ERR_PTR(-EINVAL);
180
181	init_data = config->init_data;
182	init_data->constraints.apply_uV = 0;
183
184	config->supply_name = init_data->constraints.name;
185	if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
186		config->microvolts = init_data->constraints.min_uV;
187	} else {
188		dev_err(dev,
189			 "Fixed regulator specified with variable voltages\n");
190		return ERR_PTR(-EINVAL);
191	}
192
193	if (init_data->constraints.boot_on)
194		config->enabled_at_boot = true;
195
196	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
197	of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
198
199	if (of_property_present(np, "vin-supply"))
200		config->input_supply = "vin";
201
202	return config;
203}
204
205static const struct regulator_ops fixed_voltage_ops = {
206};
207
208static const struct regulator_ops fixed_voltage_clkenabled_ops = {
209	.enable = reg_clock_enable,
210	.disable = reg_clock_disable,
211	.is_enabled = reg_is_enabled,
212};
213
214static const struct regulator_ops fixed_voltage_domain_ops = {
215	.enable = reg_domain_enable,
216	.disable = reg_domain_disable,
217	.is_enabled = reg_is_enabled,
218};
219
220static int reg_fixed_voltage_probe(struct platform_device *pdev)
221{
222	struct device *dev = &pdev->dev;
223	struct fixed_voltage_config *config;
224	struct fixed_voltage_data *drvdata;
225	const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
226	struct regulator_config cfg = { };
227	enum gpiod_flags gflags;
228	int ret;
229
230	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
231			       GFP_KERNEL);
232	if (!drvdata)
233		return -ENOMEM;
234
235	if (pdev->dev.of_node) {
236		config = of_get_fixed_voltage_config(&pdev->dev,
237						     &drvdata->desc);
238		if (IS_ERR(config))
239			return PTR_ERR(config);
240	} else {
241		config = dev_get_platdata(&pdev->dev);
242	}
243
244	if (!config)
245		return -ENOMEM;
246
247	drvdata->desc.name = devm_kstrdup(&pdev->dev,
248					  config->supply_name,
249					  GFP_KERNEL);
250	if (drvdata->desc.name == NULL) {
251		dev_err(&pdev->dev, "Failed to allocate supply name\n");
252		return -ENOMEM;
253	}
254	drvdata->desc.type = REGULATOR_VOLTAGE;
255	drvdata->desc.owner = THIS_MODULE;
256
257	if (drvtype && drvtype->has_enable_clock) {
258		drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
259
260		drvdata->enable_clock = devm_clk_get(dev, NULL);
261		if (IS_ERR(drvdata->enable_clock)) {
262			dev_err(dev, "Can't get enable-clock from devicetree\n");
263			return PTR_ERR(drvdata->enable_clock);
264		}
265	} else if (drvtype && drvtype->has_performance_state) {
266		drvdata->desc.ops = &fixed_voltage_domain_ops;
267
268		drvdata->performance_state = of_get_required_opp_performance_state(dev->of_node, 0);
269		if (drvdata->performance_state < 0) {
270			dev_err(dev, "Can't get performance state from devicetree\n");
271			return drvdata->performance_state;
272		}
273	} else {
274		drvdata->desc.ops = &fixed_voltage_ops;
275	}
276
277	drvdata->desc.enable_time = config->startup_delay;
278	drvdata->desc.off_on_delay = config->off_on_delay;
279
280	if (config->input_supply) {
281		drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
282					    config->input_supply,
283					    GFP_KERNEL);
284		if (!drvdata->desc.supply_name)
285			return -ENOMEM;
286	}
287
288	if (config->microvolts)
289		drvdata->desc.n_voltages = 1;
290
291	drvdata->desc.fixed_uV = config->microvolts;
292
293	/*
294	 * The signal will be inverted by the GPIO core if flagged so in the
295	 * descriptor.
296	 */
297	if (config->enabled_at_boot)
298		gflags = GPIOD_OUT_HIGH;
299	else
300		gflags = GPIOD_OUT_LOW;
301
302	/*
303	 * Some fixed regulators share the enable line between two
304	 * regulators which makes it necessary to get a handle on the
305	 * same descriptor for two different consumers. This will get
306	 * the GPIO descriptor, but only the first call will initialize
307	 * it so any flags such as inversion or open drain will only
308	 * be set up by the first caller and assumed identical on the
309	 * next caller.
310	 *
311	 * FIXME: find a better way to deal with this.
312	 */
313	gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
314
315	/*
316	 * Do not use devm* here: the regulator core takes over the
317	 * lifecycle management of the GPIO descriptor.
318	 */
319	cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
320	if (IS_ERR(cfg.ena_gpiod))
321		return dev_err_probe(&pdev->dev, PTR_ERR(cfg.ena_gpiod),
322				     "can't get GPIO\n");
323
324	cfg.dev = &pdev->dev;
325	cfg.init_data = config->init_data;
326	cfg.driver_data = drvdata;
327	cfg.of_node = pdev->dev.of_node;
328
329	drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
330					       &cfg);
331	if (IS_ERR(drvdata->dev)) {
332		ret = dev_err_probe(&pdev->dev, PTR_ERR(drvdata->dev),
333				    "Failed to register regulator: %ld\n",
334				    PTR_ERR(drvdata->dev));
335		return ret;
336	}
337
338	platform_set_drvdata(pdev, drvdata);
339
340	dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
341		drvdata->desc.fixed_uV);
342
343	ret = reg_fixed_get_irqs(dev, drvdata);
344	if (ret)
345		return ret;
346
347	return 0;
348}
349
350#if defined(CONFIG_OF)
351static const struct fixed_dev_type fixed_voltage_data = {
352	.has_enable_clock = false,
353};
354
355static const struct fixed_dev_type fixed_clkenable_data = {
356	.has_enable_clock = true,
357};
358
359static const struct fixed_dev_type fixed_domain_data = {
360	.has_performance_state = true,
361};
362
363static const struct of_device_id fixed_of_match[] = {
364	{
365		.compatible = "regulator-fixed",
366		.data = &fixed_voltage_data,
367	},
368	{
369		.compatible = "regulator-fixed-clock",
370		.data = &fixed_clkenable_data,
371	},
372	{
373		.compatible = "regulator-fixed-domain",
374		.data = &fixed_domain_data,
375	},
376	{
377	},
378};
379MODULE_DEVICE_TABLE(of, fixed_of_match);
380#endif
381
382static struct platform_driver regulator_fixed_voltage_driver = {
383	.probe		= reg_fixed_voltage_probe,
384	.driver		= {
385		.name		= "reg-fixed-voltage",
386		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
387		.of_match_table = of_match_ptr(fixed_of_match),
388	},
389};
390
391static int __init regulator_fixed_voltage_init(void)
392{
393	return platform_driver_register(&regulator_fixed_voltage_driver);
394}
395subsys_initcall(regulator_fixed_voltage_init);
396
397static void __exit regulator_fixed_voltage_exit(void)
398{
399	platform_driver_unregister(&regulator_fixed_voltage_driver);
400}
401module_exit(regulator_fixed_voltage_exit);
402
403MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
404MODULE_DESCRIPTION("Fixed voltage regulator");
405MODULE_LICENSE("GPL");
406MODULE_ALIAS("platform:reg-fixed-voltage");
407