1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * gpio-regulator.c
4 *
5 * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
6 *
7 * based on fixed.c
8 *
9 * Copyright 2008 Wolfson Microelectronics PLC.
10 *
11 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
12 *
13 * Copyright (c) 2009 Nokia Corporation
14 * Roger Quadros <ext-roger.quadros@nokia.com>
15 *
16 * This is useful for systems with mixed controllable and
17 * non-controllable regulators, as well as for allowing testing on
18 * systems with no controllable regulators.
19 */
20
21 #include <linux/err.h>
22 #include <linux/mutex.h>
23 #include <linux/module.h>
24 #include <linux/platform_device.h>
25 #include <linux/regulator/driver.h>
26 #include <linux/regulator/machine.h>
27 #include <linux/regulator/of_regulator.h>
28 #include <linux/regulator/gpio-regulator.h>
29 #include <linux/gpio/consumer.h>
30 #include <linux/slab.h>
31 #include <linux/of.h>
32
33 struct gpio_regulator_data {
34 struct regulator_desc desc;
35
36 struct gpio_desc **gpiods;
37 int nr_gpios;
38
39 struct gpio_regulator_state *states;
40 int nr_states;
41
42 int state;
43 };
44
gpio_regulator_get_value(struct regulator_dev * dev)45 static int gpio_regulator_get_value(struct regulator_dev *dev)
46 {
47 struct gpio_regulator_data *data = rdev_get_drvdata(dev);
48 int ptr;
49
50 for (ptr = 0; ptr < data->nr_states; ptr++)
51 if (data->states[ptr].gpios == data->state)
52 return data->states[ptr].value;
53
54 return -EINVAL;
55 }
56
gpio_regulator_set_voltage(struct regulator_dev * dev,int min_uV,int max_uV,unsigned * selector)57 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
58 int min_uV, int max_uV,
59 unsigned *selector)
60 {
61 struct gpio_regulator_data *data = rdev_get_drvdata(dev);
62 int ptr, target = 0, state, best_val = INT_MAX;
63
64 for (ptr = 0; ptr < data->nr_states; ptr++)
65 if (data->states[ptr].value < best_val &&
66 data->states[ptr].value >= min_uV &&
67 data->states[ptr].value <= max_uV) {
68 target = data->states[ptr].gpios;
69 best_val = data->states[ptr].value;
70 if (selector)
71 *selector = ptr;
72 }
73
74 if (best_val == INT_MAX)
75 return -EINVAL;
76
77 for (ptr = 0; ptr < data->nr_gpios; ptr++) {
78 state = (target & (1 << ptr)) >> ptr;
79 gpiod_set_value_cansleep(data->gpiods[ptr], state);
80 }
81 data->state = target;
82
83 return 0;
84 }
85
gpio_regulator_list_voltage(struct regulator_dev * dev,unsigned selector)86 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
87 unsigned selector)
88 {
89 struct gpio_regulator_data *data = rdev_get_drvdata(dev);
90
91 if (selector >= data->nr_states)
92 return -EINVAL;
93
94 return data->states[selector].value;
95 }
96
gpio_regulator_set_current_limit(struct regulator_dev * dev,int min_uA,int max_uA)97 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
98 int min_uA, int max_uA)
99 {
100 struct gpio_regulator_data *data = rdev_get_drvdata(dev);
101 int ptr, target = 0, state, best_val = 0;
102
103 for (ptr = 0; ptr < data->nr_states; ptr++)
104 if (data->states[ptr].value > best_val &&
105 data->states[ptr].value >= min_uA &&
106 data->states[ptr].value <= max_uA) {
107 target = data->states[ptr].gpios;
108 best_val = data->states[ptr].value;
109 }
110
111 if (best_val == 0)
112 return -EINVAL;
113
114 for (ptr = 0; ptr < data->nr_gpios; ptr++) {
115 state = (target & (1 << ptr)) >> ptr;
116 gpiod_set_value_cansleep(data->gpiods[ptr], state);
117 }
118 data->state = target;
119
120 return 0;
121 }
122
123 static const struct regulator_ops gpio_regulator_voltage_ops = {
124 .get_voltage = gpio_regulator_get_value,
125 .set_voltage = gpio_regulator_set_voltage,
126 .list_voltage = gpio_regulator_list_voltage,
127 };
128
129 static struct gpio_regulator_config *
of_get_gpio_regulator_config(struct device * dev,struct device_node * np,const struct regulator_desc * desc)130 of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
131 const struct regulator_desc *desc)
132 {
133 struct gpio_regulator_config *config;
134 const char *regtype;
135 int proplen, i;
136 int ngpios;
137 int ret;
138
139 config = devm_kzalloc(dev,
140 sizeof(struct gpio_regulator_config),
141 GFP_KERNEL);
142 if (!config)
143 return ERR_PTR(-ENOMEM);
144
145 config->init_data = of_get_regulator_init_data(dev, np, desc);
146 if (!config->init_data)
147 return ERR_PTR(-EINVAL);
148
149 config->supply_name = config->init_data->constraints.name;
150
151 if (config->init_data->constraints.boot_on)
152 config->enabled_at_boot = true;
153
154 /*
155 * Do not use: undocumented device tree property.
156 * This is kept around solely for device tree ABI stability.
157 */
158 if (of_property_read_bool(np, "enable-at-boot"))
159 config->enabled_at_boot = true;
160
161 of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
162
163 /* Fetch GPIO init levels */
164 ngpios = gpiod_count(dev, NULL);
165 if (ngpios > 0) {
166 config->gflags = devm_kzalloc(dev,
167 sizeof(enum gpiod_flags)
168 * ngpios,
169 GFP_KERNEL);
170 if (!config->gflags)
171 return ERR_PTR(-ENOMEM);
172
173 for (i = 0; i < ngpios; i++) {
174 u32 val;
175
176 ret = of_property_read_u32_index(np, "gpios-states", i,
177 &val);
178
179 /* Default to high per specification */
180 if (ret)
181 config->gflags[i] = GPIOD_OUT_HIGH;
182 else
183 config->gflags[i] =
184 val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
185 }
186 }
187 config->ngpios = ngpios;
188
189 /* Fetch states. */
190 proplen = of_property_count_u32_elems(np, "states");
191 if (proplen < 0) {
192 dev_err(dev, "No 'states' property found\n");
193 return ERR_PTR(-EINVAL);
194 }
195
196 config->states = devm_kcalloc(dev,
197 proplen / 2,
198 sizeof(struct gpio_regulator_state),
199 GFP_KERNEL);
200 if (!config->states)
201 return ERR_PTR(-ENOMEM);
202
203 for (i = 0; i < proplen / 2; i++) {
204 of_property_read_u32_index(np, "states", i * 2,
205 &config->states[i].value);
206 of_property_read_u32_index(np, "states", i * 2 + 1,
207 &config->states[i].gpios);
208 }
209 config->nr_states = i;
210
211 config->type = REGULATOR_VOLTAGE;
212 ret = of_property_read_string(np, "regulator-type", ®type);
213 if (ret >= 0) {
214 if (!strncmp("voltage", regtype, 7))
215 config->type = REGULATOR_VOLTAGE;
216 else if (!strncmp("current", regtype, 7))
217 config->type = REGULATOR_CURRENT;
218 else
219 dev_warn(dev, "Unknown regulator-type '%s'\n",
220 regtype);
221 }
222
223 return config;
224 }
225
226 static const struct regulator_ops gpio_regulator_current_ops = {
227 .get_current_limit = gpio_regulator_get_value,
228 .set_current_limit = gpio_regulator_set_current_limit,
229 };
230
gpio_regulator_probe(struct platform_device * pdev)231 static int gpio_regulator_probe(struct platform_device *pdev)
232 {
233 struct device *dev = &pdev->dev;
234 struct gpio_regulator_config *config = dev_get_platdata(dev);
235 struct device_node *np = dev->of_node;
236 struct gpio_regulator_data *drvdata;
237 struct regulator_config cfg = { };
238 struct regulator_dev *rdev;
239 enum gpiod_flags gflags;
240 int ptr, ret, state, i;
241
242 drvdata = devm_kzalloc(dev, sizeof(struct gpio_regulator_data),
243 GFP_KERNEL);
244 if (drvdata == NULL)
245 return -ENOMEM;
246
247 if (np) {
248 config = of_get_gpio_regulator_config(dev, np,
249 &drvdata->desc);
250 if (IS_ERR(config))
251 return PTR_ERR(config);
252 }
253
254 drvdata->desc.name = devm_kstrdup(dev, config->supply_name, GFP_KERNEL);
255 if (drvdata->desc.name == NULL) {
256 dev_err(dev, "Failed to allocate supply name\n");
257 return -ENOMEM;
258 }
259
260 drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
261 GFP_KERNEL);
262 if (!drvdata->gpiods)
263 return -ENOMEM;
264 for (i = 0; i < config->ngpios; i++) {
265 drvdata->gpiods[i] = devm_gpiod_get_index(dev,
266 NULL,
267 i,
268 config->gflags[i]);
269 if (IS_ERR(drvdata->gpiods[i]))
270 return PTR_ERR(drvdata->gpiods[i]);
271 /* This is good to know */
272 gpiod_set_consumer_name(drvdata->gpiods[i], drvdata->desc.name);
273 }
274 drvdata->nr_gpios = config->ngpios;
275
276 drvdata->states = devm_kmemdup(dev,
277 config->states,
278 config->nr_states *
279 sizeof(struct gpio_regulator_state),
280 GFP_KERNEL);
281 if (drvdata->states == NULL) {
282 dev_err(dev, "Failed to allocate state data\n");
283 return -ENOMEM;
284 }
285 drvdata->nr_states = config->nr_states;
286
287 drvdata->desc.owner = THIS_MODULE;
288 drvdata->desc.enable_time = config->startup_delay;
289
290 /* handle regulator type*/
291 switch (config->type) {
292 case REGULATOR_VOLTAGE:
293 drvdata->desc.type = REGULATOR_VOLTAGE;
294 drvdata->desc.ops = &gpio_regulator_voltage_ops;
295 drvdata->desc.n_voltages = config->nr_states;
296 break;
297 case REGULATOR_CURRENT:
298 drvdata->desc.type = REGULATOR_CURRENT;
299 drvdata->desc.ops = &gpio_regulator_current_ops;
300 break;
301 default:
302 dev_err(dev, "No regulator type set\n");
303 return -EINVAL;
304 }
305
306 /* build initial state from gpio init data. */
307 state = 0;
308 for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
309 if (config->gflags[ptr] == GPIOD_OUT_HIGH)
310 state |= (1 << ptr);
311 }
312 drvdata->state = state;
313
314 cfg.dev = dev;
315 cfg.init_data = config->init_data;
316 cfg.driver_data = drvdata;
317 cfg.of_node = np;
318
319 /*
320 * The signal will be inverted by the GPIO core if flagged so in the
321 * descriptor.
322 */
323 if (config->enabled_at_boot)
324 gflags = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
325 else
326 gflags = GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
327
328 cfg.ena_gpiod = gpiod_get_optional(dev, "enable", gflags);
329 if (IS_ERR(cfg.ena_gpiod))
330 return PTR_ERR(cfg.ena_gpiod);
331
332 rdev = devm_regulator_register(dev, &drvdata->desc, &cfg);
333 if (IS_ERR(rdev)) {
334 ret = PTR_ERR(rdev);
335 dev_err(dev, "Failed to register regulator: %d\n", ret);
336 return ret;
337 }
338
339 platform_set_drvdata(pdev, drvdata);
340
341 return 0;
342 }
343
344 #if defined(CONFIG_OF)
345 static const struct of_device_id regulator_gpio_of_match[] = {
346 { .compatible = "regulator-gpio", },
347 {},
348 };
349 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
350 #endif
351
352 static struct platform_driver gpio_regulator_driver = {
353 .probe = gpio_regulator_probe,
354 .driver = {
355 .name = "gpio-regulator",
356 .of_match_table = of_match_ptr(regulator_gpio_of_match),
357 },
358 };
359
gpio_regulator_init(void)360 static int __init gpio_regulator_init(void)
361 {
362 return platform_driver_register(&gpio_regulator_driver);
363 }
364 subsys_initcall(gpio_regulator_init);
365
gpio_regulator_exit(void)366 static void __exit gpio_regulator_exit(void)
367 {
368 platform_driver_unregister(&gpio_regulator_driver);
369 }
370 module_exit(gpio_regulator_exit);
371
372 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
373 MODULE_DESCRIPTION("gpio voltage regulator");
374 MODULE_LICENSE("GPL");
375 MODULE_ALIAS("platform:gpio-regulator");
376