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
36 struct 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
45 struct fixed_dev_type {
46 bool has_enable_clock;
47 bool has_performance_state;
48 };
49
reg_clock_enable(struct regulator_dev * rdev)50 static 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
reg_clock_disable(struct regulator_dev * rdev)64 static 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
reg_domain_enable(struct regulator_dev * rdev)74 static 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
reg_domain_disable(struct regulator_dev * rdev)89 static 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
reg_is_enabled(struct regulator_dev * rdev)104 static 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
reg_fixed_under_voltage_irq_handler(int irq,void * data)111 static 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 a negative error number on failure.
133 */
reg_fixed_get_irqs(struct device * dev,struct fixed_voltage_data * priv)134 static 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.
162 *
163 * Return: Pointer to a populated &struct fixed_voltage_config or %NULL if
164 * memory allocation fails.
165 */
166 static struct fixed_voltage_config *
of_get_fixed_voltage_config(struct device * dev,const struct regulator_desc * desc)167 of_get_fixed_voltage_config(struct device *dev,
168 const struct regulator_desc *desc)
169 {
170 struct fixed_voltage_config *config;
171 struct device_node *np = dev->of_node;
172 struct regulator_init_data *init_data;
173
174 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
175 GFP_KERNEL);
176 if (!config)
177 return ERR_PTR(-ENOMEM);
178
179 config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
180 if (!config->init_data)
181 return ERR_PTR(-EINVAL);
182
183 init_data = config->init_data;
184 init_data->constraints.apply_uV = 0;
185
186 config->supply_name = init_data->constraints.name;
187 if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
188 config->microvolts = init_data->constraints.min_uV;
189 } else {
190 dev_err(dev,
191 "Fixed regulator specified with variable voltages\n");
192 return ERR_PTR(-EINVAL);
193 }
194
195 if (init_data->constraints.boot_on)
196 config->enabled_at_boot = true;
197
198 of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
199 of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
200
201 if (of_property_present(np, "vin-supply"))
202 config->input_supply = "vin";
203
204 return config;
205 }
206
207 static const struct regulator_ops fixed_voltage_ops = {
208 };
209
210 static const struct regulator_ops fixed_voltage_clkenabled_ops = {
211 .enable = reg_clock_enable,
212 .disable = reg_clock_disable,
213 .is_enabled = reg_is_enabled,
214 };
215
216 static const struct regulator_ops fixed_voltage_domain_ops = {
217 .enable = reg_domain_enable,
218 .disable = reg_domain_disable,
219 .is_enabled = reg_is_enabled,
220 };
221
reg_fixed_voltage_probe(struct platform_device * pdev)222 static int reg_fixed_voltage_probe(struct platform_device *pdev)
223 {
224 struct device *dev = &pdev->dev;
225 struct fixed_voltage_config *config;
226 struct fixed_voltage_data *drvdata;
227 const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
228 struct regulator_config cfg = { };
229 enum gpiod_flags gflags;
230 int ret;
231
232 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
233 GFP_KERNEL);
234 if (!drvdata)
235 return -ENOMEM;
236
237 if (pdev->dev.of_node) {
238 config = of_get_fixed_voltage_config(&pdev->dev,
239 &drvdata->desc);
240 if (IS_ERR(config))
241 return PTR_ERR(config);
242 } else {
243 config = dev_get_platdata(&pdev->dev);
244 }
245
246 if (!config)
247 return -ENOMEM;
248
249 drvdata->desc.name = devm_kstrdup(&pdev->dev,
250 config->supply_name,
251 GFP_KERNEL);
252 if (drvdata->desc.name == NULL) {
253 dev_err(&pdev->dev, "Failed to allocate supply name\n");
254 return -ENOMEM;
255 }
256 drvdata->desc.type = REGULATOR_VOLTAGE;
257 drvdata->desc.owner = THIS_MODULE;
258
259 if (drvtype && drvtype->has_enable_clock) {
260 drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
261
262 drvdata->enable_clock = devm_clk_get(dev, NULL);
263 if (IS_ERR(drvdata->enable_clock)) {
264 dev_err(dev, "Can't get enable-clock from devicetree\n");
265 return PTR_ERR(drvdata->enable_clock);
266 }
267 } else if (drvtype && drvtype->has_performance_state) {
268 drvdata->desc.ops = &fixed_voltage_domain_ops;
269
270 drvdata->performance_state = of_get_required_opp_performance_state(dev->of_node, 0);
271 if (drvdata->performance_state < 0) {
272 dev_err(dev, "Can't get performance state from devicetree\n");
273 return drvdata->performance_state;
274 }
275 } else {
276 drvdata->desc.ops = &fixed_voltage_ops;
277 }
278
279 drvdata->desc.enable_time = config->startup_delay;
280 drvdata->desc.off_on_delay = config->off_on_delay;
281
282 if (config->input_supply) {
283 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
284 config->input_supply,
285 GFP_KERNEL);
286 if (!drvdata->desc.supply_name)
287 return -ENOMEM;
288 }
289
290 if (config->microvolts)
291 drvdata->desc.n_voltages = 1;
292
293 drvdata->desc.fixed_uV = config->microvolts;
294
295 /*
296 * The signal will be inverted by the GPIO core if flagged so in the
297 * descriptor.
298 */
299 if (config->enabled_at_boot)
300 gflags = GPIOD_OUT_HIGH;
301 else
302 gflags = GPIOD_OUT_LOW;
303
304 /*
305 * Some fixed regulators share the enable line between two
306 * regulators which makes it necessary to get a handle on the
307 * same descriptor for two different consumers. This will get
308 * the GPIO descriptor, but only the first call will initialize
309 * it so any flags such as inversion or open drain will only
310 * be set up by the first caller and assumed identical on the
311 * next caller.
312 *
313 * FIXME: find a better way to deal with this.
314 */
315 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
316
317 /*
318 * Do not use devm* here: the regulator core takes over the
319 * lifecycle management of the GPIO descriptor.
320 */
321 cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
322 if (IS_ERR(cfg.ena_gpiod))
323 return dev_err_probe(&pdev->dev, PTR_ERR(cfg.ena_gpiod),
324 "can't get GPIO\n");
325
326 cfg.dev = &pdev->dev;
327 cfg.init_data = config->init_data;
328 cfg.driver_data = drvdata;
329 cfg.of_node = pdev->dev.of_node;
330
331 drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
332 &cfg);
333 if (IS_ERR(drvdata->dev)) {
334 ret = dev_err_probe(&pdev->dev, PTR_ERR(drvdata->dev),
335 "Failed to register regulator: %ld\n",
336 PTR_ERR(drvdata->dev));
337 return ret;
338 }
339
340 platform_set_drvdata(pdev, drvdata);
341
342 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
343 drvdata->desc.fixed_uV);
344
345 ret = reg_fixed_get_irqs(dev, drvdata);
346 if (ret)
347 return ret;
348
349 return 0;
350 }
351
352 #if defined(CONFIG_OF)
353 static const struct fixed_dev_type fixed_voltage_data = {
354 .has_enable_clock = false,
355 };
356
357 static const struct fixed_dev_type fixed_clkenable_data = {
358 .has_enable_clock = true,
359 };
360
361 static const struct fixed_dev_type fixed_domain_data = {
362 .has_performance_state = true,
363 };
364
365 static const struct of_device_id fixed_of_match[] = {
366 {
367 .compatible = "regulator-fixed",
368 .data = &fixed_voltage_data,
369 },
370 {
371 .compatible = "regulator-fixed-clock",
372 .data = &fixed_clkenable_data,
373 },
374 {
375 .compatible = "regulator-fixed-domain",
376 .data = &fixed_domain_data,
377 },
378 {
379 },
380 };
381 MODULE_DEVICE_TABLE(of, fixed_of_match);
382 #endif
383
384 static struct platform_driver regulator_fixed_voltage_driver = {
385 .probe = reg_fixed_voltage_probe,
386 .driver = {
387 .name = "reg-fixed-voltage",
388 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
389 .of_match_table = of_match_ptr(fixed_of_match),
390 },
391 };
392
regulator_fixed_voltage_init(void)393 static int __init regulator_fixed_voltage_init(void)
394 {
395 return platform_driver_register(®ulator_fixed_voltage_driver);
396 }
397 subsys_initcall(regulator_fixed_voltage_init);
398
regulator_fixed_voltage_exit(void)399 static void __exit regulator_fixed_voltage_exit(void)
400 {
401 platform_driver_unregister(®ulator_fixed_voltage_driver);
402 }
403 module_exit(regulator_fixed_voltage_exit);
404
405 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
406 MODULE_DESCRIPTION("Fixed voltage regulator");
407 MODULE_LICENSE("GPL");
408 MODULE_ALIAS("platform:reg-fixed-voltage");
409