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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 <[email protected]>
8 *
9 * Copyright (c) 2009 Nokia Corporation
10 * Roger Quadros <[email protected]>
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
32struct fixed_voltage_data {
33 struct regulator_desc desc;
34 struct regulator_dev *dev;
35
36 struct clk *enable_clock;
37 unsigned int enable_counter;
38 int performance_state;
39};
40
41struct fixed_dev_type {
42 bool has_enable_clock;
43 bool has_performance_state;
44};
45
46static int reg_clock_enable(struct regulator_dev *rdev)
47{
48 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
49 int ret = 0;
50
51 ret = clk_prepare_enable(priv->enable_clock);
52 if (ret)
53 return ret;
54
55 priv->enable_counter++;
56
57 return ret;
58}
59
60static int reg_clock_disable(struct regulator_dev *rdev)
61{
62 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
63
64 clk_disable_unprepare(priv->enable_clock);
65 priv->enable_counter--;
66
67 return 0;
68}
69
70static int reg_domain_enable(struct regulator_dev *rdev)
71{
72 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
73 struct device *dev = rdev->dev.parent;
74 int ret;
75
76 ret = dev_pm_genpd_set_performance_state(dev, priv->performance_state);
77 if (ret)
78 return ret;
79
80 priv->enable_counter++;
81
82 return ret;
83}
84
85static int reg_domain_disable(struct regulator_dev *rdev)
86{
87 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
88 struct device *dev = rdev->dev.parent;
89 int ret;
90
91 ret = dev_pm_genpd_set_performance_state(dev, 0);
92 if (ret)
93 return ret;
94
95 priv->enable_counter--;
96
97 return 0;
98}
99
100static int reg_is_enabled(struct regulator_dev *rdev)
101{
102 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
103
104 return priv->enable_counter > 0;
105}
106
107static irqreturn_t reg_fixed_under_voltage_irq_handler(int irq, void *data)
108{
109 struct fixed_voltage_data *priv = data;
110 struct regulator_dev *rdev = priv->dev;
111
112 regulator_notifier_call_chain(rdev, REGULATOR_EVENT_UNDER_VOLTAGE,
113 NULL);
114
115 return IRQ_HANDLED;
116}
117
118/**
119 * reg_fixed_get_irqs - Get and register the optional IRQ for fixed voltage
120 * regulator.
121 * @dev: Pointer to the device structure.
122 * @priv: Pointer to fixed_voltage_data structure containing private data.
123 *
124 * This function tries to get the IRQ from the device firmware node.
125 * If it's an optional IRQ and not found, it returns 0.
126 * Otherwise, it attempts to request the threaded IRQ.
127 *
128 * Return: 0 on success, or a negative error number on failure.
129 */
130static int reg_fixed_get_irqs(struct device *dev,
131 struct fixed_voltage_data *priv)
132{
133 int ret;
134
135 ret = fwnode_irq_get(dev_fwnode(dev), 0);
136 /* This is optional IRQ. If not found we will get -EINVAL */
137 if (ret == -EINVAL)
138 return 0;
139 if (ret < 0)
140 return dev_err_probe(dev, ret, "Failed to get IRQ\n");
141
142 ret = devm_request_threaded_irq(dev, ret, NULL,
143 reg_fixed_under_voltage_irq_handler,
144 IRQF_ONESHOT, "under-voltage", priv);
145 if (ret)
146 return dev_err_probe(dev, ret, "Failed to request IRQ\n");
147
148 return 0;
149}
150
151/**
152 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
153 * @dev: device requesting for fixed_voltage_config
154 * @desc: regulator description
155 *
156 * Populates fixed_voltage_config structure by extracting data from device
157 * tree node.
158 *
159 * Return: Pointer to a populated &struct fixed_voltage_config or %NULL if
160 * memory allocation fails.
161 */
162static struct fixed_voltage_config *
163of_get_fixed_voltage_config(struct device *dev,
164 const struct regulator_desc *desc)
165{
166 struct fixed_voltage_config *config;
167 struct device_node *np = dev->of_node;
168 struct regulator_init_data *init_data;
169
170 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
171 GFP_KERNEL);
172 if (!config)
173 return ERR_PTR(-ENOMEM);
174
175 config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
176 if (!config->init_data)
177 return ERR_PTR(-EINVAL);
178
179 init_data = config->init_data;
180 init_data->constraints.apply_uV = 0;
181
182 config->supply_name = init_data->constraints.name;
183 if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
184 config->microvolts = init_data->constraints.min_uV;
185 } else {
186 dev_err(dev,
187 "Fixed regulator specified with variable voltages\n");
188 return ERR_PTR(-EINVAL);
189 }
190
191 if (init_data->constraints.boot_on)
192 config->enabled_at_boot = true;
193
194 of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
195 of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
196
197 if (of_property_present(np, "vin-supply"))
198 config->input_supply = "vin";
199
200 return config;
201}
202
203static const struct regulator_ops fixed_voltage_ops = {
204};
205
206static const struct regulator_ops fixed_voltage_clkenabled_ops = {
207 .enable = reg_clock_enable,
208 .disable = reg_clock_disable,
209 .is_enabled = reg_is_enabled,
210};
211
212static const struct regulator_ops fixed_voltage_domain_ops = {
213 .enable = reg_domain_enable,
214 .disable = reg_domain_disable,
215 .is_enabled = reg_is_enabled,
216};
217
218static int reg_fixed_voltage_probe(struct platform_device *pdev)
219{
220 struct device *dev = &pdev->dev;
221 struct fixed_voltage_config *config;
222 struct fixed_voltage_data *drvdata;
223 const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
224 struct regulator_config cfg = { };
225 enum gpiod_flags gflags;
226 int ret;
227
228 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
229 GFP_KERNEL);
230 if (!drvdata)
231 return -ENOMEM;
232
233 if (pdev->dev.of_node) {
234 config = of_get_fixed_voltage_config(&pdev->dev,
235 &drvdata->desc);
236 if (IS_ERR(config))
237 return PTR_ERR(config);
238 } else {
239 config = dev_get_platdata(&pdev->dev);
240 }
241
242 if (!config)
243 return -ENOMEM;
244
245 drvdata->desc.name = devm_kstrdup(&pdev->dev,
246 config->supply_name,
247 GFP_KERNEL);
248 if (drvdata->desc.name == NULL) {
249 dev_err(&pdev->dev, "Failed to allocate supply name\n");
250 return -ENOMEM;
251 }
252 drvdata->desc.type = REGULATOR_VOLTAGE;
253 drvdata->desc.owner = THIS_MODULE;
254
255 if (drvtype && drvtype->has_enable_clock) {
256 drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
257
258 drvdata->enable_clock = devm_clk_get(dev, NULL);
259 if (IS_ERR(drvdata->enable_clock)) {
260 dev_err(dev, "Can't get enable-clock from devicetree\n");
261 return PTR_ERR(drvdata->enable_clock);
262 }
263 } else if (drvtype && drvtype->has_performance_state) {
264 drvdata->desc.ops = &fixed_voltage_domain_ops;
265
266 drvdata->performance_state = of_get_required_opp_performance_state(dev->of_node, 0);
267 if (drvdata->performance_state < 0) {
268 dev_err(dev, "Can't get performance state from devicetree\n");
269 return drvdata->performance_state;
270 }
271 } else {
272 drvdata->desc.ops = &fixed_voltage_ops;
273 }
274
275 drvdata->desc.enable_time = config->startup_delay;
276 drvdata->desc.off_on_delay = config->off_on_delay;
277
278 if (config->input_supply) {
279 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
280 config->input_supply,
281 GFP_KERNEL);
282 if (!drvdata->desc.supply_name)
283 return -ENOMEM;
284 }
285
286 if (config->microvolts)
287 drvdata->desc.n_voltages = 1;
288
289 drvdata->desc.fixed_uV = config->microvolts;
290
291 /*
292 * The signal will be inverted by the GPIO core if flagged so in the
293 * descriptor.
294 */
295 if (config->enabled_at_boot)
296 gflags = GPIOD_OUT_HIGH;
297 else
298 gflags = GPIOD_OUT_LOW;
299
300 /*
301 * Some fixed regulators share the enable line between two
302 * regulators which makes it necessary to get a handle on the
303 * same descriptor for two different consumers. This will get
304 * the GPIO descriptor, but only the first call will initialize
305 * it so any flags such as inversion or open drain will only
306 * be set up by the first caller and assumed identical on the
307 * next caller.
308 *
309 * FIXME: find a better way to deal with this.
310 */
311 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
312
313 /*
314 * Do not use devm* here: the regulator core takes over the
315 * lifecycle management of the GPIO descriptor.
316 */
317 cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
318 if (IS_ERR(cfg.ena_gpiod))
319 return dev_err_probe(&pdev->dev, PTR_ERR(cfg.ena_gpiod),
320 "can't get GPIO\n");
321
322 cfg.dev = &pdev->dev;
323 cfg.init_data = config->init_data;
324 cfg.driver_data = drvdata;
325 cfg.of_node = pdev->dev.of_node;
326
327 drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
328 &cfg);
329 if (IS_ERR(drvdata->dev))
330 return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->dev),
331 "Failed to register regulator: %ld\n",
332 PTR_ERR(drvdata->dev));
333
334 platform_set_drvdata(pdev, drvdata);
335
336 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
337 drvdata->desc.fixed_uV);
338
339 ret = reg_fixed_get_irqs(dev, drvdata);
340 if (ret)
341 return ret;
342
343 return 0;
344}
345
346#if defined(CONFIG_OF)
347static const struct fixed_dev_type fixed_voltage_data = {
348 .has_enable_clock = false,
349};
350
351static const struct fixed_dev_type fixed_clkenable_data = {
352 .has_enable_clock = true,
353};
354
355static const struct fixed_dev_type fixed_domain_data = {
356 .has_performance_state = true,
357};
358
359static const struct of_device_id fixed_of_match[] = {
360 {
361 .compatible = "regulator-fixed",
362 .data = &fixed_voltage_data,
363 },
364 {
365 .compatible = "regulator-fixed-clock",
366 .data = &fixed_clkenable_data,
367 },
368 {
369 .compatible = "regulator-fixed-domain",
370 .data = &fixed_domain_data,
371 },
372 {
373 },
374};
375MODULE_DEVICE_TABLE(of, fixed_of_match);
376#endif
377
378static struct platform_driver regulator_fixed_voltage_driver = {
379 .probe = reg_fixed_voltage_probe,
380 .driver = {
381 .name = "reg-fixed-voltage",
382 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
383 .of_match_table = of_match_ptr(fixed_of_match),
384 },
385};
386
387static int __init regulator_fixed_voltage_init(void)
388{
389 return platform_driver_register(&regulator_fixed_voltage_driver);
390}
391subsys_initcall(regulator_fixed_voltage_init);
392
393static void __exit regulator_fixed_voltage_exit(void)
394{
395 platform_driver_unregister(&regulator_fixed_voltage_driver);
396}
397module_exit(regulator_fixed_voltage_exit);
398
399MODULE_AUTHOR("Mark Brown <[email protected]>");
400MODULE_DESCRIPTION("Fixed voltage regulator");
401MODULE_LICENSE("GPL");
402MODULE_ALIAS("platform:reg-fixed-voltage");