1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for voltage controller regulators
4 *
5 * Copyright (C) 2017 Google, Inc.
6 */
7
8 #include <linux/delay.h>
9 #include <linux/err.h>
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 #include <linux/of_device.h>
14 #include <linux/regulator/coupler.h>
15 #include <linux/regulator/driver.h>
16 #include <linux/regulator/of_regulator.h>
17 #include <linux/sort.h>
18
19 #include "internal.h"
20
21 struct vctrl_voltage_range {
22 int min_uV;
23 int max_uV;
24 };
25
26 struct vctrl_voltage_ranges {
27 struct vctrl_voltage_range ctrl;
28 struct vctrl_voltage_range out;
29 };
30
31 struct vctrl_voltage_table {
32 int ctrl;
33 int out;
34 int ovp_min_sel;
35 };
36
37 struct vctrl_data {
38 struct regulator_dev *rdev;
39 struct regulator_desc desc;
40 struct regulator *ctrl_reg;
41 bool enabled;
42 unsigned int min_slew_down_rate;
43 unsigned int ovp_threshold;
44 struct vctrl_voltage_ranges vrange;
45 struct vctrl_voltage_table *vtable;
46 unsigned int sel;
47 };
48
vctrl_calc_ctrl_voltage(struct vctrl_data * vctrl,int out_uV)49 static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV)
50 {
51 struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
52 struct vctrl_voltage_range *out = &vctrl->vrange.out;
53
54 return ctrl->min_uV +
55 DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) *
56 (ctrl->max_uV - ctrl->min_uV),
57 out->max_uV - out->min_uV);
58 }
59
vctrl_calc_output_voltage(struct vctrl_data * vctrl,int ctrl_uV)60 static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV)
61 {
62 struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
63 struct vctrl_voltage_range *out = &vctrl->vrange.out;
64
65 if (ctrl_uV < 0) {
66 pr_err("vctrl: failed to get control voltage\n");
67 return ctrl_uV;
68 }
69
70 if (ctrl_uV < ctrl->min_uV)
71 return out->min_uV;
72
73 if (ctrl_uV > ctrl->max_uV)
74 return out->max_uV;
75
76 return out->min_uV +
77 DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) *
78 (out->max_uV - out->min_uV),
79 ctrl->max_uV - ctrl->min_uV);
80 }
81
vctrl_get_voltage(struct regulator_dev * rdev)82 static int vctrl_get_voltage(struct regulator_dev *rdev)
83 {
84 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
85 int ctrl_uV = regulator_get_voltage_rdev(vctrl->ctrl_reg->rdev);
86
87 return vctrl_calc_output_voltage(vctrl, ctrl_uV);
88 }
89
vctrl_set_voltage(struct regulator_dev * rdev,int req_min_uV,int req_max_uV,unsigned int * selector)90 static int vctrl_set_voltage(struct regulator_dev *rdev,
91 int req_min_uV, int req_max_uV,
92 unsigned int *selector)
93 {
94 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
95 struct regulator *ctrl_reg = vctrl->ctrl_reg;
96 int orig_ctrl_uV = regulator_get_voltage_rdev(ctrl_reg->rdev);
97 int uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV);
98 int ret;
99
100 if (req_min_uV >= uV || !vctrl->ovp_threshold)
101 /* voltage rising or no OVP */
102 return regulator_set_voltage_rdev(ctrl_reg->rdev,
103 vctrl_calc_ctrl_voltage(vctrl, req_min_uV),
104 vctrl_calc_ctrl_voltage(vctrl, req_max_uV),
105 PM_SUSPEND_ON);
106
107 while (uV > req_min_uV) {
108 int max_drop_uV = (uV * vctrl->ovp_threshold) / 100;
109 int next_uV;
110 int next_ctrl_uV;
111 int delay;
112
113 /* Make sure no infinite loop even in crazy cases */
114 if (max_drop_uV == 0)
115 max_drop_uV = 1;
116
117 next_uV = max_t(int, req_min_uV, uV - max_drop_uV);
118 next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV);
119
120 ret = regulator_set_voltage_rdev(ctrl_reg->rdev,
121 next_ctrl_uV,
122 next_ctrl_uV,
123 PM_SUSPEND_ON);
124 if (ret)
125 goto err;
126
127 delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate);
128 usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
129
130 uV = next_uV;
131 }
132
133 return 0;
134
135 err:
136 /* Try to go back to original voltage */
137 regulator_set_voltage_rdev(ctrl_reg->rdev, orig_ctrl_uV, orig_ctrl_uV,
138 PM_SUSPEND_ON);
139
140 return ret;
141 }
142
vctrl_get_voltage_sel(struct regulator_dev * rdev)143 static int vctrl_get_voltage_sel(struct regulator_dev *rdev)
144 {
145 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
146
147 return vctrl->sel;
148 }
149
vctrl_set_voltage_sel(struct regulator_dev * rdev,unsigned int selector)150 static int vctrl_set_voltage_sel(struct regulator_dev *rdev,
151 unsigned int selector)
152 {
153 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
154 struct regulator *ctrl_reg = vctrl->ctrl_reg;
155 unsigned int orig_sel = vctrl->sel;
156 int ret;
157
158 if (selector >= rdev->desc->n_voltages)
159 return -EINVAL;
160
161 if (selector >= vctrl->sel || !vctrl->ovp_threshold) {
162 /* voltage rising or no OVP */
163 ret = regulator_set_voltage_rdev(ctrl_reg->rdev,
164 vctrl->vtable[selector].ctrl,
165 vctrl->vtable[selector].ctrl,
166 PM_SUSPEND_ON);
167 if (!ret)
168 vctrl->sel = selector;
169
170 return ret;
171 }
172
173 while (vctrl->sel != selector) {
174 unsigned int next_sel;
175 int delay;
176
177 if (selector >= vctrl->vtable[vctrl->sel].ovp_min_sel)
178 next_sel = selector;
179 else
180 next_sel = vctrl->vtable[vctrl->sel].ovp_min_sel;
181
182 ret = regulator_set_voltage_rdev(ctrl_reg->rdev,
183 vctrl->vtable[next_sel].ctrl,
184 vctrl->vtable[next_sel].ctrl,
185 PM_SUSPEND_ON);
186 if (ret) {
187 dev_err(&rdev->dev,
188 "failed to set control voltage to %duV\n",
189 vctrl->vtable[next_sel].ctrl);
190 goto err;
191 }
192 vctrl->sel = next_sel;
193
194 delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out -
195 vctrl->vtable[next_sel].out,
196 vctrl->min_slew_down_rate);
197 usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
198 }
199
200 return 0;
201
202 err:
203 if (vctrl->sel != orig_sel) {
204 /* Try to go back to original voltage */
205 if (!regulator_set_voltage_rdev(ctrl_reg->rdev,
206 vctrl->vtable[orig_sel].ctrl,
207 vctrl->vtable[orig_sel].ctrl,
208 PM_SUSPEND_ON))
209 vctrl->sel = orig_sel;
210 else
211 dev_warn(&rdev->dev,
212 "failed to restore original voltage\n");
213 }
214
215 return ret;
216 }
217
vctrl_list_voltage(struct regulator_dev * rdev,unsigned int selector)218 static int vctrl_list_voltage(struct regulator_dev *rdev,
219 unsigned int selector)
220 {
221 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
222
223 if (selector >= rdev->desc->n_voltages)
224 return -EINVAL;
225
226 return vctrl->vtable[selector].out;
227 }
228
vctrl_parse_dt(struct platform_device * pdev,struct vctrl_data * vctrl)229 static int vctrl_parse_dt(struct platform_device *pdev,
230 struct vctrl_data *vctrl)
231 {
232 int ret;
233 struct device_node *np = pdev->dev.of_node;
234 u32 pval;
235 u32 vrange_ctrl[2];
236
237 vctrl->ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl");
238 if (IS_ERR(vctrl->ctrl_reg))
239 return PTR_ERR(vctrl->ctrl_reg);
240
241 ret = of_property_read_u32(np, "ovp-threshold-percent", &pval);
242 if (!ret) {
243 vctrl->ovp_threshold = pval;
244 if (vctrl->ovp_threshold > 100) {
245 dev_err(&pdev->dev,
246 "ovp-threshold-percent (%u) > 100\n",
247 vctrl->ovp_threshold);
248 return -EINVAL;
249 }
250 }
251
252 ret = of_property_read_u32(np, "min-slew-down-rate", &pval);
253 if (!ret) {
254 vctrl->min_slew_down_rate = pval;
255
256 /* We use the value as int and as divider; sanity check */
257 if (vctrl->min_slew_down_rate == 0) {
258 dev_err(&pdev->dev,
259 "min-slew-down-rate must not be 0\n");
260 return -EINVAL;
261 } else if (vctrl->min_slew_down_rate > INT_MAX) {
262 dev_err(&pdev->dev, "min-slew-down-rate (%u) too big\n",
263 vctrl->min_slew_down_rate);
264 return -EINVAL;
265 }
266 }
267
268 if (vctrl->ovp_threshold && !vctrl->min_slew_down_rate) {
269 dev_err(&pdev->dev,
270 "ovp-threshold-percent requires min-slew-down-rate\n");
271 return -EINVAL;
272 }
273
274 ret = of_property_read_u32(np, "regulator-min-microvolt", &pval);
275 if (ret) {
276 dev_err(&pdev->dev,
277 "failed to read regulator-min-microvolt: %d\n", ret);
278 return ret;
279 }
280 vctrl->vrange.out.min_uV = pval;
281
282 ret = of_property_read_u32(np, "regulator-max-microvolt", &pval);
283 if (ret) {
284 dev_err(&pdev->dev,
285 "failed to read regulator-max-microvolt: %d\n", ret);
286 return ret;
287 }
288 vctrl->vrange.out.max_uV = pval;
289
290 ret = of_property_read_u32_array(np, "ctrl-voltage-range", vrange_ctrl,
291 2);
292 if (ret) {
293 dev_err(&pdev->dev, "failed to read ctrl-voltage-range: %d\n",
294 ret);
295 return ret;
296 }
297
298 if (vrange_ctrl[0] >= vrange_ctrl[1]) {
299 dev_err(&pdev->dev, "ctrl-voltage-range is invalid: %d-%d\n",
300 vrange_ctrl[0], vrange_ctrl[1]);
301 return -EINVAL;
302 }
303
304 vctrl->vrange.ctrl.min_uV = vrange_ctrl[0];
305 vctrl->vrange.ctrl.max_uV = vrange_ctrl[1];
306
307 return 0;
308 }
309
vctrl_cmp_ctrl_uV(const void * a,const void * b)310 static int vctrl_cmp_ctrl_uV(const void *a, const void *b)
311 {
312 const struct vctrl_voltage_table *at = a;
313 const struct vctrl_voltage_table *bt = b;
314
315 return at->ctrl - bt->ctrl;
316 }
317
vctrl_init_vtable(struct platform_device * pdev)318 static int vctrl_init_vtable(struct platform_device *pdev)
319 {
320 struct vctrl_data *vctrl = platform_get_drvdata(pdev);
321 struct regulator_desc *rdesc = &vctrl->desc;
322 struct regulator *ctrl_reg = vctrl->ctrl_reg;
323 struct vctrl_voltage_range *vrange_ctrl = &vctrl->vrange.ctrl;
324 int n_voltages;
325 int ctrl_uV;
326 int i, idx_vt;
327
328 n_voltages = regulator_count_voltages(ctrl_reg);
329
330 rdesc->n_voltages = n_voltages;
331
332 /* determine number of steps within the range of the vctrl regulator */
333 for (i = 0; i < n_voltages; i++) {
334 ctrl_uV = regulator_list_voltage(ctrl_reg, i);
335
336 if (ctrl_uV < vrange_ctrl->min_uV ||
337 ctrl_uV > vrange_ctrl->max_uV)
338 rdesc->n_voltages--;
339 }
340
341 if (rdesc->n_voltages == 0) {
342 dev_err(&pdev->dev, "invalid configuration\n");
343 return -EINVAL;
344 }
345
346 vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages,
347 sizeof(struct vctrl_voltage_table),
348 GFP_KERNEL);
349 if (!vctrl->vtable)
350 return -ENOMEM;
351
352 /* create mapping control <=> output voltage */
353 for (i = 0, idx_vt = 0; i < n_voltages; i++) {
354 ctrl_uV = regulator_list_voltage(ctrl_reg, i);
355
356 if (ctrl_uV < vrange_ctrl->min_uV ||
357 ctrl_uV > vrange_ctrl->max_uV)
358 continue;
359
360 vctrl->vtable[idx_vt].ctrl = ctrl_uV;
361 vctrl->vtable[idx_vt].out =
362 vctrl_calc_output_voltage(vctrl, ctrl_uV);
363 idx_vt++;
364 }
365
366 /* we rely on the table to be ordered by ascending voltage */
367 sort(vctrl->vtable, rdesc->n_voltages,
368 sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV,
369 NULL);
370
371 /* pre-calculate OVP-safe downward transitions */
372 for (i = rdesc->n_voltages - 1; i > 0; i--) {
373 int j;
374 int ovp_min_uV = (vctrl->vtable[i].out *
375 (100 - vctrl->ovp_threshold)) / 100;
376
377 for (j = 0; j < i; j++) {
378 if (vctrl->vtable[j].out >= ovp_min_uV) {
379 vctrl->vtable[i].ovp_min_sel = j;
380 break;
381 }
382 }
383
384 if (j == i) {
385 dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n",
386 vctrl->vtable[i].out);
387 /* use next lowest voltage */
388 vctrl->vtable[i].ovp_min_sel = i - 1;
389 }
390 }
391
392 return 0;
393 }
394
vctrl_enable(struct regulator_dev * rdev)395 static int vctrl_enable(struct regulator_dev *rdev)
396 {
397 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
398 int ret = regulator_enable(vctrl->ctrl_reg);
399
400 if (!ret)
401 vctrl->enabled = true;
402
403 return ret;
404 }
405
vctrl_disable(struct regulator_dev * rdev)406 static int vctrl_disable(struct regulator_dev *rdev)
407 {
408 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
409 int ret = regulator_disable(vctrl->ctrl_reg);
410
411 if (!ret)
412 vctrl->enabled = false;
413
414 return ret;
415 }
416
vctrl_is_enabled(struct regulator_dev * rdev)417 static int vctrl_is_enabled(struct regulator_dev *rdev)
418 {
419 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
420
421 return vctrl->enabled;
422 }
423
424 static const struct regulator_ops vctrl_ops_cont = {
425 .enable = vctrl_enable,
426 .disable = vctrl_disable,
427 .is_enabled = vctrl_is_enabled,
428 .get_voltage = vctrl_get_voltage,
429 .set_voltage = vctrl_set_voltage,
430 };
431
432 static const struct regulator_ops vctrl_ops_non_cont = {
433 .enable = vctrl_enable,
434 .disable = vctrl_disable,
435 .is_enabled = vctrl_is_enabled,
436 .set_voltage_sel = vctrl_set_voltage_sel,
437 .get_voltage_sel = vctrl_get_voltage_sel,
438 .list_voltage = vctrl_list_voltage,
439 .map_voltage = regulator_map_voltage_iterate,
440 };
441
vctrl_probe(struct platform_device * pdev)442 static int vctrl_probe(struct platform_device *pdev)
443 {
444 struct device_node *np = pdev->dev.of_node;
445 struct vctrl_data *vctrl;
446 const struct regulator_init_data *init_data;
447 struct regulator_desc *rdesc;
448 struct regulator_config cfg = { };
449 struct vctrl_voltage_range *vrange_ctrl;
450 int ctrl_uV;
451 int ret;
452
453 vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data),
454 GFP_KERNEL);
455 if (!vctrl)
456 return -ENOMEM;
457
458 platform_set_drvdata(pdev, vctrl);
459
460 ret = vctrl_parse_dt(pdev, vctrl);
461 if (ret)
462 return ret;
463
464 vrange_ctrl = &vctrl->vrange.ctrl;
465
466 rdesc = &vctrl->desc;
467 rdesc->name = "vctrl";
468 rdesc->type = REGULATOR_VOLTAGE;
469 rdesc->owner = THIS_MODULE;
470
471 if ((regulator_get_linear_step(vctrl->ctrl_reg) == 1) ||
472 (regulator_count_voltages(vctrl->ctrl_reg) == -EINVAL)) {
473 rdesc->continuous_voltage_range = true;
474 rdesc->ops = &vctrl_ops_cont;
475 } else {
476 rdesc->ops = &vctrl_ops_non_cont;
477 }
478
479 init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc);
480 if (!init_data)
481 return -ENOMEM;
482
483 cfg.of_node = np;
484 cfg.dev = &pdev->dev;
485 cfg.driver_data = vctrl;
486 cfg.init_data = init_data;
487
488 if (!rdesc->continuous_voltage_range) {
489 ret = vctrl_init_vtable(pdev);
490 if (ret)
491 return ret;
492
493 ctrl_uV = regulator_get_voltage_rdev(vctrl->ctrl_reg->rdev);
494 if (ctrl_uV < 0) {
495 dev_err(&pdev->dev, "failed to get control voltage\n");
496 return ctrl_uV;
497 }
498
499 /* determine current voltage selector from control voltage */
500 if (ctrl_uV < vrange_ctrl->min_uV) {
501 vctrl->sel = 0;
502 } else if (ctrl_uV > vrange_ctrl->max_uV) {
503 vctrl->sel = rdesc->n_voltages - 1;
504 } else {
505 int i;
506
507 for (i = 0; i < rdesc->n_voltages; i++) {
508 if (ctrl_uV == vctrl->vtable[i].ctrl) {
509 vctrl->sel = i;
510 break;
511 }
512 }
513 }
514 }
515
516 vctrl->rdev = devm_regulator_register(&pdev->dev, rdesc, &cfg);
517 if (IS_ERR(vctrl->rdev)) {
518 ret = PTR_ERR(vctrl->rdev);
519 dev_err(&pdev->dev, "failed to register regulator: %d\n", ret);
520 return ret;
521 }
522
523 return 0;
524 }
525
526 static const struct of_device_id vctrl_of_match[] = {
527 { .compatible = "vctrl-regulator", },
528 {},
529 };
530 MODULE_DEVICE_TABLE(of, vctrl_of_match);
531
532 static struct platform_driver vctrl_driver = {
533 .probe = vctrl_probe,
534 .driver = {
535 .name = "vctrl-regulator",
536 .of_match_table = of_match_ptr(vctrl_of_match),
537 },
538 };
539
540 module_platform_driver(vctrl_driver);
541
542 MODULE_DESCRIPTION("Voltage Controlled Regulator Driver");
543 MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
544 MODULE_LICENSE("GPL v2");
545