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/platform_device.h> |
14 | #include <linux/regulator/driver.h> |
15 | #include <linux/regulator/machine.h> |
16 | #include <linux/regulator/of_regulator.h> |
17 | #include <linux/of.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(pwm: drvdata->pwm, state: &pwm_state); |
62 | dutycycle = pwm_get_relative_duty_cycle(state: &pwm_state, scale: 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(pwm: drvdata->pwm, state: &pstate); |
90 | pwm_set_relative_duty_cycle(state: &pstate, |
91 | duty_cycle: drvdata->duty_cycle_table[selector].dutycycle, scale: 100); |
92 | |
93 | ret = pwm_apply_might_sleep(pwm: drvdata->pwm, state: &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(rdev: dev); |
118 | |
119 | gpiod_set_value_cansleep(desc: drvdata->enb_gpio, value: 1); |
120 | |
121 | return pwm_enable(pwm: drvdata->pwm); |
122 | } |
123 | |
124 | static int pwm_regulator_disable(struct regulator_dev *dev) |
125 | { |
126 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev: dev); |
127 | |
128 | pwm_disable(pwm: drvdata->pwm); |
129 | |
130 | gpiod_set_value_cansleep(desc: drvdata->enb_gpio, value: 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(rdev: dev); |
138 | |
139 | if (drvdata->enb_gpio && !gpiod_get_value_cansleep(desc: drvdata->enb_gpio)) |
140 | return false; |
141 | |
142 | return pwm_is_enabled(pwm: 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(pwm: drvdata->pwm, state: &pstate); |
159 | |
160 | if (!pstate.enabled) { |
161 | if (pstate.polarity == PWM_POLARITY_INVERSED) |
162 | pstate.duty_cycle = pstate.period; |
163 | else |
164 | pstate.duty_cycle = 0; |
165 | } |
166 | |
167 | voltage = pwm_get_relative_duty_cycle(state: &pstate, scale: duty_unit); |
168 | if (voltage < min(max_uV_duty, min_uV_duty) || |
169 | voltage > max(max_uV_duty, min_uV_duty)) |
170 | return -ENOTRECOVERABLE; |
171 | |
172 | /* |
173 | * The dutycycle for min_uV might be greater than the one for max_uV. |
174 | * This is happening when the user needs an inversed polarity, but the |
175 | * PWM device does not support inversing it in hardware. |
176 | */ |
177 | if (max_uV_duty < min_uV_duty) { |
178 | voltage = min_uV_duty - voltage; |
179 | diff_duty = min_uV_duty - max_uV_duty; |
180 | } else { |
181 | voltage = voltage - min_uV_duty; |
182 | diff_duty = max_uV_duty - min_uV_duty; |
183 | } |
184 | |
185 | voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty); |
186 | |
187 | return voltage + min_uV; |
188 | } |
189 | |
190 | static int pwm_regulator_set_voltage(struct regulator_dev *rdev, |
191 | int req_min_uV, int req_max_uV, |
192 | unsigned int *selector) |
193 | { |
194 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
195 | unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle; |
196 | unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle; |
197 | unsigned int duty_unit = drvdata->continuous.dutycycle_unit; |
198 | int min_uV = rdev->constraints->min_uV; |
199 | int max_uV = rdev->constraints->max_uV; |
200 | int diff_uV = max_uV - min_uV; |
201 | struct pwm_state pstate; |
202 | unsigned int diff_duty; |
203 | unsigned int dutycycle; |
204 | int ret; |
205 | |
206 | pwm_init_state(pwm: drvdata->pwm, state: &pstate); |
207 | |
208 | /* |
209 | * The dutycycle for min_uV might be greater than the one for max_uV. |
210 | * This is happening when the user needs an inversed polarity, but the |
211 | * PWM device does not support inversing it in hardware. |
212 | */ |
213 | if (max_uV_duty < min_uV_duty) |
214 | diff_duty = min_uV_duty - max_uV_duty; |
215 | else |
216 | diff_duty = max_uV_duty - min_uV_duty; |
217 | |
218 | dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) * |
219 | diff_duty, |
220 | diff_uV); |
221 | |
222 | if (max_uV_duty < min_uV_duty) |
223 | dutycycle = min_uV_duty - dutycycle; |
224 | else |
225 | dutycycle = min_uV_duty + dutycycle; |
226 | |
227 | pwm_set_relative_duty_cycle(state: &pstate, duty_cycle: dutycycle, scale: duty_unit); |
228 | |
229 | ret = pwm_apply_might_sleep(pwm: drvdata->pwm, state: &pstate); |
230 | if (ret) { |
231 | dev_err(&rdev->dev, "Failed to configure PWM: %d\n" , ret); |
232 | return ret; |
233 | } |
234 | |
235 | return 0; |
236 | } |
237 | |
238 | static const struct regulator_ops pwm_regulator_voltage_table_ops = { |
239 | .set_voltage_sel = pwm_regulator_set_voltage_sel, |
240 | .get_voltage_sel = pwm_regulator_get_voltage_sel, |
241 | .list_voltage = pwm_regulator_list_voltage, |
242 | .map_voltage = regulator_map_voltage_iterate, |
243 | .enable = pwm_regulator_enable, |
244 | .disable = pwm_regulator_disable, |
245 | .is_enabled = pwm_regulator_is_enabled, |
246 | }; |
247 | |
248 | static const struct regulator_ops pwm_regulator_voltage_continuous_ops = { |
249 | .get_voltage = pwm_regulator_get_voltage, |
250 | .set_voltage = pwm_regulator_set_voltage, |
251 | .enable = pwm_regulator_enable, |
252 | .disable = pwm_regulator_disable, |
253 | .is_enabled = pwm_regulator_is_enabled, |
254 | }; |
255 | |
256 | static const struct regulator_desc pwm_regulator_desc = { |
257 | .name = "pwm-regulator" , |
258 | .type = REGULATOR_VOLTAGE, |
259 | .owner = THIS_MODULE, |
260 | .supply_name = "pwm" , |
261 | }; |
262 | |
263 | static int pwm_regulator_init_table(struct platform_device *pdev, |
264 | struct pwm_regulator_data *drvdata) |
265 | { |
266 | struct device_node *np = pdev->dev.of_node; |
267 | struct pwm_voltages *duty_cycle_table; |
268 | unsigned int length = 0; |
269 | int ret; |
270 | |
271 | of_find_property(np, name: "voltage-table" , lenp: &length); |
272 | |
273 | if ((length < sizeof(*duty_cycle_table)) || |
274 | (length % sizeof(*duty_cycle_table))) |
275 | return dev_err_probe(dev: &pdev->dev, err: -EINVAL, |
276 | fmt: "voltage-table length(%d) is invalid\n" , |
277 | length); |
278 | |
279 | duty_cycle_table = devm_kzalloc(dev: &pdev->dev, size: length, GFP_KERNEL); |
280 | if (!duty_cycle_table) |
281 | return -ENOMEM; |
282 | |
283 | ret = of_property_read_u32_array(np, propname: "voltage-table" , |
284 | out_values: (u32 *)duty_cycle_table, |
285 | sz: length / sizeof(u32)); |
286 | if (ret) |
287 | return dev_err_probe(dev: &pdev->dev, err: ret, |
288 | fmt: "Failed to read voltage-table\n" ); |
289 | |
290 | drvdata->state = -ENOTRECOVERABLE; |
291 | drvdata->duty_cycle_table = duty_cycle_table; |
292 | drvdata->desc.ops = &pwm_regulator_voltage_table_ops; |
293 | drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table); |
294 | |
295 | return 0; |
296 | } |
297 | |
298 | static int pwm_regulator_init_continuous(struct platform_device *pdev, |
299 | struct pwm_regulator_data *drvdata) |
300 | { |
301 | u32 dutycycle_range[2] = { 0, 100 }; |
302 | u32 dutycycle_unit = 100; |
303 | |
304 | drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops; |
305 | drvdata->desc.continuous_voltage_range = true; |
306 | |
307 | of_property_read_u32_array(np: pdev->dev.of_node, |
308 | propname: "pwm-dutycycle-range" , |
309 | out_values: dutycycle_range, sz: 2); |
310 | of_property_read_u32(np: pdev->dev.of_node, propname: "pwm-dutycycle-unit" , |
311 | out_value: &dutycycle_unit); |
312 | |
313 | if (dutycycle_range[0] > dutycycle_unit || |
314 | dutycycle_range[1] > dutycycle_unit) |
315 | return -EINVAL; |
316 | |
317 | drvdata->continuous.dutycycle_unit = dutycycle_unit; |
318 | drvdata->continuous.min_uV_dutycycle = dutycycle_range[0]; |
319 | drvdata->continuous.max_uV_dutycycle = dutycycle_range[1]; |
320 | |
321 | return 0; |
322 | } |
323 | |
324 | static int pwm_regulator_init_boot_on(struct platform_device *pdev, |
325 | struct pwm_regulator_data *drvdata, |
326 | const struct regulator_init_data *init_data) |
327 | { |
328 | struct pwm_state pstate; |
329 | |
330 | if (!init_data->constraints.boot_on || drvdata->enb_gpio) |
331 | return 0; |
332 | |
333 | pwm_get_state(pwm: drvdata->pwm, state: &pstate); |
334 | if (pstate.enabled) |
335 | return 0; |
336 | |
337 | /* |
338 | * Update the duty cycle so the output does not change |
339 | * when the regulator core enables the regulator (and |
340 | * thus the PWM channel). |
341 | */ |
342 | if (pstate.polarity == PWM_POLARITY_INVERSED) |
343 | pstate.duty_cycle = pstate.period; |
344 | else |
345 | pstate.duty_cycle = 0; |
346 | |
347 | return pwm_apply_might_sleep(pwm: drvdata->pwm, state: &pstate); |
348 | } |
349 | |
350 | static int pwm_regulator_probe(struct platform_device *pdev) |
351 | { |
352 | const struct regulator_init_data *init_data; |
353 | struct pwm_regulator_data *drvdata; |
354 | struct regulator_dev *regulator; |
355 | struct regulator_config config = { }; |
356 | struct device_node *np = pdev->dev.of_node; |
357 | enum gpiod_flags gpio_flags; |
358 | int ret; |
359 | |
360 | if (!np) |
361 | return dev_err_probe(dev: &pdev->dev, err: -EINVAL, |
362 | fmt: "Device Tree node missing\n" ); |
363 | |
364 | drvdata = devm_kzalloc(dev: &pdev->dev, size: sizeof(*drvdata), GFP_KERNEL); |
365 | if (!drvdata) |
366 | return -ENOMEM; |
367 | |
368 | memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc)); |
369 | |
370 | if (of_property_present(np, propname: "voltage-table" )) |
371 | ret = pwm_regulator_init_table(pdev, drvdata); |
372 | else |
373 | ret = pwm_regulator_init_continuous(pdev, drvdata); |
374 | if (ret) |
375 | return ret; |
376 | |
377 | init_data = of_get_regulator_init_data(dev: &pdev->dev, node: np, |
378 | desc: &drvdata->desc); |
379 | if (!init_data) |
380 | return -ENOMEM; |
381 | |
382 | config.of_node = np; |
383 | config.dev = &pdev->dev; |
384 | config.driver_data = drvdata; |
385 | config.init_data = init_data; |
386 | |
387 | drvdata->pwm = devm_pwm_get(dev: &pdev->dev, NULL); |
388 | if (IS_ERR(ptr: drvdata->pwm)) |
389 | return dev_err_probe(dev: &pdev->dev, err: PTR_ERR(ptr: drvdata->pwm), |
390 | fmt: "Failed to get PWM\n" ); |
391 | |
392 | if (init_data->constraints.boot_on || init_data->constraints.always_on) |
393 | gpio_flags = GPIOD_OUT_HIGH; |
394 | else |
395 | gpio_flags = GPIOD_OUT_LOW; |
396 | drvdata->enb_gpio = devm_gpiod_get_optional(dev: &pdev->dev, con_id: "enable" , |
397 | flags: gpio_flags); |
398 | if (IS_ERR(ptr: drvdata->enb_gpio)) { |
399 | ret = PTR_ERR(ptr: drvdata->enb_gpio); |
400 | return dev_err_probe(dev: &pdev->dev, err: ret, fmt: "Failed to get enable GPIO\n" ); |
401 | } |
402 | |
403 | ret = pwm_adjust_config(pwm: drvdata->pwm); |
404 | if (ret) |
405 | return ret; |
406 | |
407 | ret = pwm_regulator_init_boot_on(pdev, drvdata, init_data); |
408 | if (ret) |
409 | return dev_err_probe(dev: &pdev->dev, err: ret, |
410 | fmt: "Failed to apply boot_on settings\n" ); |
411 | |
412 | regulator = devm_regulator_register(dev: &pdev->dev, |
413 | regulator_desc: &drvdata->desc, config: &config); |
414 | if (IS_ERR(ptr: regulator)) { |
415 | ret = PTR_ERR(ptr: regulator); |
416 | return dev_err_probe(dev: &pdev->dev, err: ret, |
417 | fmt: "Failed to register regulator %s\n" , |
418 | drvdata->desc.name); |
419 | } |
420 | |
421 | return 0; |
422 | } |
423 | |
424 | static const struct of_device_id __maybe_unused pwm_of_match[] = { |
425 | { .compatible = "pwm-regulator" }, |
426 | { }, |
427 | }; |
428 | MODULE_DEVICE_TABLE(of, pwm_of_match); |
429 | |
430 | static struct platform_driver pwm_regulator_driver = { |
431 | .driver = { |
432 | .name = "pwm-regulator" , |
433 | .probe_type = PROBE_PREFER_ASYNCHRONOUS, |
434 | .of_match_table = of_match_ptr(pwm_of_match), |
435 | }, |
436 | .probe = pwm_regulator_probe, |
437 | }; |
438 | |
439 | module_platform_driver(pwm_regulator_driver); |
440 | |
441 | MODULE_LICENSE("GPL" ); |
442 | MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>" ); |
443 | MODULE_DESCRIPTION("PWM Regulator Driver" ); |
444 | MODULE_ALIAS("platform:pwm-regulator" ); |
445 | |