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
33 struct 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
42 struct fixed_dev_type {
43 bool has_enable_clock;
44 bool has_performance_state;
45 };
46
reg_clock_enable(struct regulator_dev * rdev)47 static 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
reg_clock_disable(struct regulator_dev * rdev)61 static 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
reg_domain_enable(struct regulator_dev * rdev)71 static 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
reg_domain_disable(struct regulator_dev * rdev)86 static 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
reg_is_enabled(struct regulator_dev * rdev)101 static 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 */
118 static struct fixed_voltage_config *
of_get_fixed_voltage_config(struct device * dev,const struct regulator_desc * desc)119 of_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
159 static const struct regulator_ops fixed_voltage_ops = {
160 };
161
162 static 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
168 static 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
reg_fixed_voltage_probe(struct platform_device * pdev)174 static 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)
301 static const struct fixed_dev_type fixed_voltage_data = {
302 .has_enable_clock = false,
303 };
304
305 static const struct fixed_dev_type fixed_clkenable_data = {
306 .has_enable_clock = true,
307 };
308
309 static const struct fixed_dev_type fixed_domain_data = {
310 .has_performance_state = true,
311 };
312
313 static 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 };
329 MODULE_DEVICE_TABLE(of, fixed_of_match);
330 #endif
331
332 static 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
regulator_fixed_voltage_init(void)341 static int __init regulator_fixed_voltage_init(void)
342 {
343 return platform_driver_register(®ulator_fixed_voltage_driver);
344 }
345 subsys_initcall(regulator_fixed_voltage_init);
346
regulator_fixed_voltage_exit(void)347 static void __exit regulator_fixed_voltage_exit(void)
348 {
349 platform_driver_unregister(®ulator_fixed_voltage_driver);
350 }
351 module_exit(regulator_fixed_voltage_exit);
352
353 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
354 MODULE_DESCRIPTION("Fixed voltage regulator");
355 MODULE_LICENSE("GPL");
356 MODULE_ALIAS("platform:reg-fixed-voltage");
357