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_state(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 | voltage = pwm_get_relative_duty_cycle(state: &pstate, scale: 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(pwm: drvdata->pwm, state: &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(state: &pstate, duty_cycle: dutycycle, scale: duty_unit); |
218 | |
219 | ret = pwm_apply_state(pwm: drvdata->pwm, state: &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, name: "voltage-table" , lenp: &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(dev: &pdev->dev, size: length, GFP_KERNEL); |
271 | if (!duty_cycle_table) |
272 | return -ENOMEM; |
273 | |
274 | ret = of_property_read_u32_array(np, propname: "voltage-table" , |
275 | out_values: (u32 *)duty_cycle_table, |
276 | sz: 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 = -ENOTRECOVERABLE; |
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(np: pdev->dev.of_node, |
300 | propname: "pwm-dutycycle-range" , |
301 | out_values: dutycycle_range, sz: 2); |
302 | of_property_read_u32(np: pdev->dev.of_node, propname: "pwm-dutycycle-unit" , |
303 | out_value: &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(dev: &pdev->dev, size: 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_property_present(np, propname: "voltage-table" )) |
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(dev: &pdev->dev, node: np, |
345 | desc: &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(dev: &pdev->dev, NULL); |
355 | if (IS_ERR(ptr: drvdata->pwm)) |
356 | return dev_err_probe(dev: &pdev->dev, err: PTR_ERR(ptr: drvdata->pwm), |
357 | fmt: "Failed to get PWM\n" ); |
358 | |
359 | if (init_data->constraints.boot_on || init_data->constraints.always_on) |
360 | gpio_flags = GPIOD_OUT_HIGH; |
361 | else |
362 | gpio_flags = GPIOD_OUT_LOW; |
363 | drvdata->enb_gpio = devm_gpiod_get_optional(dev: &pdev->dev, con_id: "enable" , |
364 | flags: gpio_flags); |
365 | if (IS_ERR(ptr: drvdata->enb_gpio)) { |
366 | ret = PTR_ERR(ptr: drvdata->enb_gpio); |
367 | dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n" , ret); |
368 | return ret; |
369 | } |
370 | |
371 | ret = pwm_adjust_config(pwm: drvdata->pwm); |
372 | if (ret) |
373 | return ret; |
374 | |
375 | regulator = devm_regulator_register(dev: &pdev->dev, |
376 | regulator_desc: &drvdata->desc, config: &config); |
377 | if (IS_ERR(ptr: regulator)) { |
378 | ret = PTR_ERR(ptr: regulator); |
379 | dev_err(&pdev->dev, "Failed to register regulator %s: %d\n" , |
380 | drvdata->desc.name, ret); |
381 | return ret; |
382 | } |
383 | |
384 | return 0; |
385 | } |
386 | |
387 | static const struct of_device_id __maybe_unused pwm_of_match[] = { |
388 | { .compatible = "pwm-regulator" }, |
389 | { }, |
390 | }; |
391 | MODULE_DEVICE_TABLE(of, pwm_of_match); |
392 | |
393 | static struct platform_driver pwm_regulator_driver = { |
394 | .driver = { |
395 | .name = "pwm-regulator" , |
396 | .probe_type = PROBE_PREFER_ASYNCHRONOUS, |
397 | .of_match_table = of_match_ptr(pwm_of_match), |
398 | }, |
399 | .probe = pwm_regulator_probe, |
400 | }; |
401 | |
402 | module_platform_driver(pwm_regulator_driver); |
403 | |
404 | MODULE_LICENSE("GPL" ); |
405 | MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>" ); |
406 | MODULE_DESCRIPTION("PWM Regulator Driver" ); |
407 | MODULE_ALIAS("platform:pwm-regulator" ); |
408 | |