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/of_device.h>
29 #include <linux/regulator/of_regulator.h>
30 #include <linux/regulator/machine.h>
31 #include <linux/clk.h>
32
33
34 struct fixed_voltage_data {
35 struct regulator_desc desc;
36 struct regulator_dev *dev;
37
38 struct clk *enable_clock;
39 unsigned int enable_counter;
40 int performance_state;
41 };
42
43 struct fixed_dev_type {
44 bool has_enable_clock;
45 bool has_performance_state;
46 };
47
reg_clock_enable(struct regulator_dev * rdev)48 static int reg_clock_enable(struct regulator_dev *rdev)
49 {
50 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
51 int ret = 0;
52
53 ret = clk_prepare_enable(priv->enable_clock);
54 if (ret)
55 return ret;
56
57 priv->enable_counter++;
58
59 return ret;
60 }
61
reg_clock_disable(struct regulator_dev * rdev)62 static int reg_clock_disable(struct regulator_dev *rdev)
63 {
64 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
65
66 clk_disable_unprepare(priv->enable_clock);
67 priv->enable_counter--;
68
69 return 0;
70 }
71
reg_domain_enable(struct regulator_dev * rdev)72 static int reg_domain_enable(struct regulator_dev *rdev)
73 {
74 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
75 struct device *dev = rdev->dev.parent;
76 int ret;
77
78 ret = dev_pm_genpd_set_performance_state(dev, priv->performance_state);
79 if (ret)
80 return ret;
81
82 priv->enable_counter++;
83
84 return ret;
85 }
86
reg_domain_disable(struct regulator_dev * rdev)87 static int reg_domain_disable(struct regulator_dev *rdev)
88 {
89 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
90 struct device *dev = rdev->dev.parent;
91 int ret;
92
93 ret = dev_pm_genpd_set_performance_state(dev, 0);
94 if (ret)
95 return ret;
96
97 priv->enable_counter--;
98
99 return 0;
100 }
101
reg_is_enabled(struct regulator_dev * rdev)102 static int reg_is_enabled(struct regulator_dev *rdev)
103 {
104 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
105
106 return priv->enable_counter > 0;
107 }
108
109
110 /**
111 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
112 * @dev: device requesting for fixed_voltage_config
113 * @desc: regulator description
114 *
115 * Populates fixed_voltage_config structure by extracting data from device
116 * tree node, returns a pointer to the populated structure of NULL if memory
117 * alloc fails.
118 */
119 static struct fixed_voltage_config *
of_get_fixed_voltage_config(struct device * dev,const struct regulator_desc * desc)120 of_get_fixed_voltage_config(struct device *dev,
121 const struct regulator_desc *desc)
122 {
123 struct fixed_voltage_config *config;
124 struct device_node *np = dev->of_node;
125 struct regulator_init_data *init_data;
126
127 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
128 GFP_KERNEL);
129 if (!config)
130 return ERR_PTR(-ENOMEM);
131
132 config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
133 if (!config->init_data)
134 return ERR_PTR(-EINVAL);
135
136 init_data = config->init_data;
137 init_data->constraints.apply_uV = 0;
138
139 config->supply_name = init_data->constraints.name;
140 if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
141 config->microvolts = init_data->constraints.min_uV;
142 } else {
143 dev_err(dev,
144 "Fixed regulator specified with variable voltages\n");
145 return ERR_PTR(-EINVAL);
146 }
147
148 if (init_data->constraints.boot_on)
149 config->enabled_at_boot = true;
150
151 of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
152 of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
153
154 if (of_find_property(np, "vin-supply", NULL))
155 config->input_supply = "vin";
156
157 return config;
158 }
159
160 static const struct regulator_ops fixed_voltage_ops = {
161 };
162
163 static const struct regulator_ops fixed_voltage_clkenabled_ops = {
164 .enable = reg_clock_enable,
165 .disable = reg_clock_disable,
166 .is_enabled = reg_is_enabled,
167 };
168
169 static const struct regulator_ops fixed_voltage_domain_ops = {
170 .enable = reg_domain_enable,
171 .disable = reg_domain_disable,
172 .is_enabled = reg_is_enabled,
173 };
174
reg_fixed_voltage_probe(struct platform_device * pdev)175 static int reg_fixed_voltage_probe(struct platform_device *pdev)
176 {
177 struct device *dev = &pdev->dev;
178 struct fixed_voltage_config *config;
179 struct fixed_voltage_data *drvdata;
180 const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
181 struct regulator_config cfg = { };
182 enum gpiod_flags gflags;
183 int ret;
184
185 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
186 GFP_KERNEL);
187 if (!drvdata)
188 return -ENOMEM;
189
190 if (pdev->dev.of_node) {
191 config = of_get_fixed_voltage_config(&pdev->dev,
192 &drvdata->desc);
193 if (IS_ERR(config))
194 return PTR_ERR(config);
195 } else {
196 config = dev_get_platdata(&pdev->dev);
197 }
198
199 if (!config)
200 return -ENOMEM;
201
202 drvdata->desc.name = devm_kstrdup(&pdev->dev,
203 config->supply_name,
204 GFP_KERNEL);
205 if (drvdata->desc.name == NULL) {
206 dev_err(&pdev->dev, "Failed to allocate supply name\n");
207 return -ENOMEM;
208 }
209 drvdata->desc.type = REGULATOR_VOLTAGE;
210 drvdata->desc.owner = THIS_MODULE;
211
212 if (drvtype && drvtype->has_enable_clock) {
213 drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
214
215 drvdata->enable_clock = devm_clk_get(dev, NULL);
216 if (IS_ERR(drvdata->enable_clock)) {
217 dev_err(dev, "Can't get enable-clock from devicetree\n");
218 return PTR_ERR(drvdata->enable_clock);
219 }
220 } else if (drvtype && drvtype->has_performance_state) {
221 drvdata->desc.ops = &fixed_voltage_domain_ops;
222
223 drvdata->performance_state = of_get_required_opp_performance_state(dev->of_node, 0);
224 if (drvdata->performance_state < 0) {
225 dev_err(dev, "Can't get performance state from devicetree\n");
226 return drvdata->performance_state;
227 }
228 } else {
229 drvdata->desc.ops = &fixed_voltage_ops;
230 }
231
232 drvdata->desc.enable_time = config->startup_delay;
233 drvdata->desc.off_on_delay = config->off_on_delay;
234
235 if (config->input_supply) {
236 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
237 config->input_supply,
238 GFP_KERNEL);
239 if (!drvdata->desc.supply_name)
240 return -ENOMEM;
241 }
242
243 if (config->microvolts)
244 drvdata->desc.n_voltages = 1;
245
246 drvdata->desc.fixed_uV = config->microvolts;
247
248 /*
249 * The signal will be inverted by the GPIO core if flagged so in the
250 * descriptor.
251 */
252 if (config->enabled_at_boot)
253 gflags = GPIOD_OUT_HIGH;
254 else
255 gflags = GPIOD_OUT_LOW;
256
257 /*
258 * Some fixed regulators share the enable line between two
259 * regulators which makes it necessary to get a handle on the
260 * same descriptor for two different consumers. This will get
261 * the GPIO descriptor, but only the first call will initialize
262 * it so any flags such as inversion or open drain will only
263 * be set up by the first caller and assumed identical on the
264 * next caller.
265 *
266 * FIXME: find a better way to deal with this.
267 */
268 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
269
270 /*
271 * Do not use devm* here: the regulator core takes over the
272 * lifecycle management of the GPIO descriptor.
273 */
274 cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
275 if (IS_ERR(cfg.ena_gpiod))
276 return dev_err_probe(&pdev->dev, PTR_ERR(cfg.ena_gpiod),
277 "can't get GPIO\n");
278
279 cfg.dev = &pdev->dev;
280 cfg.init_data = config->init_data;
281 cfg.driver_data = drvdata;
282 cfg.of_node = pdev->dev.of_node;
283
284 drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
285 &cfg);
286 if (IS_ERR(drvdata->dev)) {
287 ret = dev_err_probe(&pdev->dev, PTR_ERR(drvdata->dev),
288 "Failed to register regulator: %ld\n",
289 PTR_ERR(drvdata->dev));
290 return ret;
291 }
292
293 platform_set_drvdata(pdev, drvdata);
294
295 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
296 drvdata->desc.fixed_uV);
297
298 return 0;
299 }
300
301 #if defined(CONFIG_OF)
302 static const struct fixed_dev_type fixed_voltage_data = {
303 .has_enable_clock = false,
304 };
305
306 static const struct fixed_dev_type fixed_clkenable_data = {
307 .has_enable_clock = true,
308 };
309
310 static const struct fixed_dev_type fixed_domain_data = {
311 .has_performance_state = true,
312 };
313
314 static const struct of_device_id fixed_of_match[] = {
315 {
316 .compatible = "regulator-fixed",
317 .data = &fixed_voltage_data,
318 },
319 {
320 .compatible = "regulator-fixed-clock",
321 .data = &fixed_clkenable_data,
322 },
323 {
324 .compatible = "regulator-fixed-domain",
325 .data = &fixed_domain_data,
326 },
327 {
328 },
329 };
330 MODULE_DEVICE_TABLE(of, fixed_of_match);
331 #endif
332
333 static struct platform_driver regulator_fixed_voltage_driver = {
334 .probe = reg_fixed_voltage_probe,
335 .driver = {
336 .name = "reg-fixed-voltage",
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