1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Regulator driver for PWM Regulators
4  *
5  * Copyright (C) 2014 - STMicroelectronics Inc.
6  *
7  * Author: Lee Jones <lee.jones@linaro.org>
8  */
9 
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/err.h>
13 #include <linux/regulator/driver.h>
14 #include <linux/regulator/machine.h>
15 #include <linux/regulator/of_regulator.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/pwm.h>
19 #include <linux/gpio/consumer.h>
20 
21 struct pwm_continuous_reg_data {
22 	unsigned int min_uV_dutycycle;
23 	unsigned int max_uV_dutycycle;
24 	unsigned int dutycycle_unit;
25 };
26 
27 struct pwm_regulator_data {
28 	/*  Shared */
29 	struct pwm_device *pwm;
30 
31 	/* Voltage table */
32 	struct pwm_voltages *duty_cycle_table;
33 
34 	/* Continuous mode info */
35 	struct pwm_continuous_reg_data continuous;
36 
37 	/* regulator descriptor */
38 	struct regulator_desc desc;
39 
40 	int state;
41 
42 	/* Enable GPIO */
43 	struct gpio_desc *enb_gpio;
44 };
45 
46 struct pwm_voltages {
47 	unsigned int uV;
48 	unsigned int dutycycle;
49 };
50 
51 /**
52  * Voltage table call-backs
53  */
54 static void pwm_regulator_init_state(struct regulator_dev *rdev)
55 {
56 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
57 	struct pwm_state pwm_state;
58 	unsigned int dutycycle;
59 	int i;
60 
61 	pwm_get_state(drvdata->pwm, &pwm_state);
62 	dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
63 
64 	for (i = 0; i < rdev->desc->n_voltages; i++) {
65 		if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
66 			drvdata->state = i;
67 			return;
68 		}
69 	}
70 }
71 
72 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
73 {
74 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
75 
76 	if (drvdata->state < 0)
77 		pwm_regulator_init_state(rdev);
78 
79 	return drvdata->state;
80 }
81 
82 static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
83 					 unsigned selector)
84 {
85 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
86 	struct pwm_state pstate;
87 	int ret;
88 
89 	pwm_init_state(drvdata->pwm, &pstate);
90 	pwm_set_relative_duty_cycle(&pstate,
91 			drvdata->duty_cycle_table[selector].dutycycle, 100);
92 
93 	ret = pwm_apply_state(drvdata->pwm, &pstate);
94 	if (ret) {
95 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
96 		return ret;
97 	}
98 
99 	drvdata->state = selector;
100 
101 	return 0;
102 }
103 
104 static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
105 				      unsigned selector)
106 {
107 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
108 
109 	if (selector >= rdev->desc->n_voltages)
110 		return -EINVAL;
111 
112 	return drvdata->duty_cycle_table[selector].uV;
113 }
114 
115 static int pwm_regulator_enable(struct regulator_dev *dev)
116 {
117 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
118 
119 	gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
120 
121 	return pwm_enable(drvdata->pwm);
122 }
123 
124 static int pwm_regulator_disable(struct regulator_dev *dev)
125 {
126 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
127 
128 	pwm_disable(drvdata->pwm);
129 
130 	gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
131 
132 	return 0;
133 }
134 
135 static int pwm_regulator_is_enabled(struct regulator_dev *dev)
136 {
137 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
138 
139 	if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
140 		return false;
141 
142 	return pwm_is_enabled(drvdata->pwm);
143 }
144 
145 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
146 {
147 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
148 	unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
149 	unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
150 	unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
151 	int min_uV = rdev->constraints->min_uV;
152 	int max_uV = rdev->constraints->max_uV;
153 	int diff_uV = max_uV - min_uV;
154 	struct pwm_state pstate;
155 	unsigned int diff_duty;
156 	unsigned int voltage;
157 
158 	pwm_get_state(drvdata->pwm, &pstate);
159 
160 	voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
161 
162 	/*
163 	 * The dutycycle for min_uV might be greater than the one for max_uV.
164 	 * This is happening when the user needs an inversed polarity, but the
165 	 * PWM device does not support inversing it in hardware.
166 	 */
167 	if (max_uV_duty < min_uV_duty) {
168 		voltage = min_uV_duty - voltage;
169 		diff_duty = min_uV_duty - max_uV_duty;
170 	} else {
171 		voltage = voltage - min_uV_duty;
172 		diff_duty = max_uV_duty - min_uV_duty;
173 	}
174 
175 	voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
176 
177 	return voltage + min_uV;
178 }
179 
180 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
181 				     int req_min_uV, int req_max_uV,
182 				     unsigned int *selector)
183 {
184 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
185 	unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
186 	unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
187 	unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
188 	int min_uV = rdev->constraints->min_uV;
189 	int max_uV = rdev->constraints->max_uV;
190 	int diff_uV = max_uV - min_uV;
191 	struct pwm_state pstate;
192 	unsigned int diff_duty;
193 	unsigned int dutycycle;
194 	int ret;
195 
196 	pwm_init_state(drvdata->pwm, &pstate);
197 
198 	/*
199 	 * The dutycycle for min_uV might be greater than the one for max_uV.
200 	 * This is happening when the user needs an inversed polarity, but the
201 	 * PWM device does not support inversing it in hardware.
202 	 */
203 	if (max_uV_duty < min_uV_duty)
204 		diff_duty = min_uV_duty - max_uV_duty;
205 	else
206 		diff_duty = max_uV_duty - min_uV_duty;
207 
208 	dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
209 					  diff_duty,
210 					  diff_uV);
211 
212 	if (max_uV_duty < min_uV_duty)
213 		dutycycle = min_uV_duty - dutycycle;
214 	else
215 		dutycycle = min_uV_duty + dutycycle;
216 
217 	pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
218 
219 	ret = pwm_apply_state(drvdata->pwm, &pstate);
220 	if (ret) {
221 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
222 		return ret;
223 	}
224 
225 	return 0;
226 }
227 
228 static const struct regulator_ops pwm_regulator_voltage_table_ops = {
229 	.set_voltage_sel = pwm_regulator_set_voltage_sel,
230 	.get_voltage_sel = pwm_regulator_get_voltage_sel,
231 	.list_voltage    = pwm_regulator_list_voltage,
232 	.map_voltage     = regulator_map_voltage_iterate,
233 	.enable          = pwm_regulator_enable,
234 	.disable         = pwm_regulator_disable,
235 	.is_enabled      = pwm_regulator_is_enabled,
236 };
237 
238 static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
239 	.get_voltage = pwm_regulator_get_voltage,
240 	.set_voltage = pwm_regulator_set_voltage,
241 	.enable          = pwm_regulator_enable,
242 	.disable         = pwm_regulator_disable,
243 	.is_enabled      = pwm_regulator_is_enabled,
244 };
245 
246 static const struct regulator_desc pwm_regulator_desc = {
247 	.name		= "pwm-regulator",
248 	.type		= REGULATOR_VOLTAGE,
249 	.owner		= THIS_MODULE,
250 	.supply_name    = "pwm",
251 };
252 
253 static int pwm_regulator_init_table(struct platform_device *pdev,
254 				    struct pwm_regulator_data *drvdata)
255 {
256 	struct device_node *np = pdev->dev.of_node;
257 	struct pwm_voltages *duty_cycle_table;
258 	unsigned int length = 0;
259 	int ret;
260 
261 	of_find_property(np, "voltage-table", &length);
262 
263 	if ((length < sizeof(*duty_cycle_table)) ||
264 	    (length % sizeof(*duty_cycle_table))) {
265 		dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
266 			length);
267 		return -EINVAL;
268 	}
269 
270 	duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
271 	if (!duty_cycle_table)
272 		return -ENOMEM;
273 
274 	ret = of_property_read_u32_array(np, "voltage-table",
275 					 (u32 *)duty_cycle_table,
276 					 length / sizeof(u32));
277 	if (ret) {
278 		dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
279 		return ret;
280 	}
281 
282 	drvdata->state			= -EINVAL;
283 	drvdata->duty_cycle_table	= duty_cycle_table;
284 	drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
285 	drvdata->desc.n_voltages	= length / sizeof(*duty_cycle_table);
286 
287 	return 0;
288 }
289 
290 static int pwm_regulator_init_continuous(struct platform_device *pdev,
291 					 struct pwm_regulator_data *drvdata)
292 {
293 	u32 dutycycle_range[2] = { 0, 100 };
294 	u32 dutycycle_unit = 100;
295 
296 	drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
297 	drvdata->desc.continuous_voltage_range = true;
298 
299 	of_property_read_u32_array(pdev->dev.of_node,
300 				   "pwm-dutycycle-range",
301 				   dutycycle_range, 2);
302 	of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
303 			     &dutycycle_unit);
304 
305 	if (dutycycle_range[0] > dutycycle_unit ||
306 	    dutycycle_range[1] > dutycycle_unit)
307 		return -EINVAL;
308 
309 	drvdata->continuous.dutycycle_unit = dutycycle_unit;
310 	drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
311 	drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
312 
313 	return 0;
314 }
315 
316 static int pwm_regulator_probe(struct platform_device *pdev)
317 {
318 	const struct regulator_init_data *init_data;
319 	struct pwm_regulator_data *drvdata;
320 	struct regulator_dev *regulator;
321 	struct regulator_config config = { };
322 	struct device_node *np = pdev->dev.of_node;
323 	enum gpiod_flags gpio_flags;
324 	int ret;
325 
326 	if (!np) {
327 		dev_err(&pdev->dev, "Device Tree node missing\n");
328 		return -EINVAL;
329 	}
330 
331 	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
332 	if (!drvdata)
333 		return -ENOMEM;
334 
335 	memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
336 
337 	if (of_find_property(np, "voltage-table", NULL))
338 		ret = pwm_regulator_init_table(pdev, drvdata);
339 	else
340 		ret = pwm_regulator_init_continuous(pdev, drvdata);
341 	if (ret)
342 		return ret;
343 
344 	init_data = of_get_regulator_init_data(&pdev->dev, np,
345 					       &drvdata->desc);
346 	if (!init_data)
347 		return -ENOMEM;
348 
349 	config.of_node = np;
350 	config.dev = &pdev->dev;
351 	config.driver_data = drvdata;
352 	config.init_data = init_data;
353 
354 	drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
355 	if (IS_ERR(drvdata->pwm)) {
356 		ret = PTR_ERR(drvdata->pwm);
357 		if (ret == -EPROBE_DEFER)
358 			dev_dbg(&pdev->dev,
359 				"Failed to get PWM, deferring probe\n");
360 		else
361 			dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
362 		return ret;
363 	}
364 
365 	if (init_data->constraints.boot_on || init_data->constraints.always_on)
366 		gpio_flags = GPIOD_OUT_HIGH;
367 	else
368 		gpio_flags = GPIOD_OUT_LOW;
369 	drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
370 						    gpio_flags);
371 	if (IS_ERR(drvdata->enb_gpio)) {
372 		ret = PTR_ERR(drvdata->enb_gpio);
373 		dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
374 		return ret;
375 	}
376 
377 	ret = pwm_adjust_config(drvdata->pwm);
378 	if (ret)
379 		return ret;
380 
381 	regulator = devm_regulator_register(&pdev->dev,
382 					    &drvdata->desc, &config);
383 	if (IS_ERR(regulator)) {
384 		ret = PTR_ERR(regulator);
385 		dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
386 			drvdata->desc.name, ret);
387 		return ret;
388 	}
389 
390 	return 0;
391 }
392 
393 static const struct of_device_id pwm_of_match[] = {
394 	{ .compatible = "pwm-regulator" },
395 	{ },
396 };
397 MODULE_DEVICE_TABLE(of, pwm_of_match);
398 
399 static struct platform_driver pwm_regulator_driver = {
400 	.driver = {
401 		.name		= "pwm-regulator",
402 		.of_match_table = of_match_ptr(pwm_of_match),
403 	},
404 	.probe = pwm_regulator_probe,
405 };
406 
407 module_platform_driver(pwm_regulator_driver);
408 
409 MODULE_LICENSE("GPL");
410 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
411 MODULE_DESCRIPTION("PWM Regulator Driver");
412 MODULE_ALIAS("platform:pwm-regulator");
413