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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/platform_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
21struct vctrl_voltage_range {
22 int min_uV;
23 int max_uV;
24};
25
26struct vctrl_voltage_ranges {
27 struct vctrl_voltage_range ctrl;
28 struct vctrl_voltage_range out;
29};
30
31struct vctrl_voltage_table {
32 int ctrl;
33 int out;
34 int ovp_min_sel;
35};
36
37struct vctrl_data {
38 struct regulator_dev *rdev;
39 struct regulator_desc desc;
40 bool enabled;
41 unsigned int min_slew_down_rate;
42 unsigned int ovp_threshold;
43 struct vctrl_voltage_ranges vrange;
44 struct vctrl_voltage_table *vtable;
45 unsigned int sel;
46};
47
48static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV)
49{
50 struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
51 struct vctrl_voltage_range *out = &vctrl->vrange.out;
52
53 return ctrl->min_uV +
54 DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) *
55 (ctrl->max_uV - ctrl->min_uV),
56 out->max_uV - out->min_uV);
57}
58
59static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV)
60{
61 struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
62 struct vctrl_voltage_range *out = &vctrl->vrange.out;
63
64 if (ctrl_uV < 0) {
65 pr_err("vctrl: failed to get control voltage\n");
66 return ctrl_uV;
67 }
68
69 if (ctrl_uV < ctrl->min_uV)
70 return out->min_uV;
71
72 if (ctrl_uV > ctrl->max_uV)
73 return out->max_uV;
74
75 return out->min_uV +
76 DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) *
77 (out->max_uV - out->min_uV),
78 ctrl->max_uV - ctrl->min_uV);
79}
80
81static int vctrl_get_voltage(struct regulator_dev *rdev)
82{
83 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
84 int ctrl_uV;
85
86 if (!rdev->supply)
87 return -EPROBE_DEFER;
88
89 ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev);
90
91 return vctrl_calc_output_voltage(vctrl, ctrl_uV);
92}
93
94static int vctrl_set_voltage(struct regulator_dev *rdev,
95 int req_min_uV, int req_max_uV,
96 unsigned int *selector)
97{
98 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
99 int orig_ctrl_uV;
100 int uV;
101 int ret;
102
103 if (!rdev->supply)
104 return -EPROBE_DEFER;
105
106 orig_ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev);
107 uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV);
108
109 if (req_min_uV >= uV || !vctrl->ovp_threshold)
110 /* voltage rising or no OVP */
111 return regulator_set_voltage_rdev(rdev->supply->rdev,
112 vctrl_calc_ctrl_voltage(vctrl, req_min_uV),
113 vctrl_calc_ctrl_voltage(vctrl, req_max_uV),
114 PM_SUSPEND_ON);
115
116 while (uV > req_min_uV) {
117 int max_drop_uV = (uV * vctrl->ovp_threshold) / 100;
118 int next_uV;
119 int next_ctrl_uV;
120 int delay;
121
122 /* Make sure no infinite loop even in crazy cases */
123 if (max_drop_uV == 0)
124 max_drop_uV = 1;
125
126 next_uV = max_t(int, req_min_uV, uV - max_drop_uV);
127 next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV);
128
129 ret = regulator_set_voltage_rdev(rdev->supply->rdev,
130 next_ctrl_uV,
131 next_ctrl_uV,
132 PM_SUSPEND_ON);
133 if (ret)
134 goto err;
135
136 delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate);
137 usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
138
139 uV = next_uV;
140 }
141
142 return 0;
143
144err:
145 /* Try to go back to original voltage */
146 regulator_set_voltage_rdev(rdev->supply->rdev, orig_ctrl_uV, orig_ctrl_uV,
147 PM_SUSPEND_ON);
148
149 return ret;
150}
151
152static int vctrl_get_voltage_sel(struct regulator_dev *rdev)
153{
154 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
155
156 return vctrl->sel;
157}
158
159static int vctrl_set_voltage_sel(struct regulator_dev *rdev,
160 unsigned int selector)
161{
162 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
163 unsigned int orig_sel = vctrl->sel;
164 int ret;
165
166 if (!rdev->supply)
167 return -EPROBE_DEFER;
168
169 if (selector >= rdev->desc->n_voltages)
170 return -EINVAL;
171
172 if (selector >= vctrl->sel || !vctrl->ovp_threshold) {
173 /* voltage rising or no OVP */
174 ret = regulator_set_voltage_rdev(rdev->supply->rdev,
175 vctrl->vtable[selector].ctrl,
176 vctrl->vtable[selector].ctrl,
177 PM_SUSPEND_ON);
178 if (!ret)
179 vctrl->sel = selector;
180
181 return ret;
182 }
183
184 while (vctrl->sel != selector) {
185 unsigned int next_sel;
186 int delay;
187
188 next_sel = max_t(unsigned int, selector, vctrl->vtable[vctrl->sel].ovp_min_sel);
189
190 ret = regulator_set_voltage_rdev(rdev->supply->rdev,
191 vctrl->vtable[next_sel].ctrl,
192 vctrl->vtable[next_sel].ctrl,
193 PM_SUSPEND_ON);
194 if (ret) {
195 dev_err(&rdev->dev,
196 "failed to set control voltage to %duV\n",
197 vctrl->vtable[next_sel].ctrl);
198 goto err;
199 }
200 vctrl->sel = next_sel;
201
202 delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out -
203 vctrl->vtable[next_sel].out,
204 vctrl->min_slew_down_rate);
205 usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
206 }
207
208 return 0;
209
210err:
211 if (vctrl->sel != orig_sel) {
212 /* Try to go back to original voltage */
213 if (!regulator_set_voltage_rdev(rdev->supply->rdev,
214 vctrl->vtable[orig_sel].ctrl,
215 vctrl->vtable[orig_sel].ctrl,
216 PM_SUSPEND_ON))
217 vctrl->sel = orig_sel;
218 else
219 dev_warn(&rdev->dev,
220 "failed to restore original voltage\n");
221 }
222
223 return ret;
224}
225
226static int vctrl_list_voltage(struct regulator_dev *rdev,
227 unsigned int selector)
228{
229 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
230
231 if (selector >= rdev->desc->n_voltages)
232 return -EINVAL;
233
234 return vctrl->vtable[selector].out;
235}
236
237static int vctrl_parse_dt(struct platform_device *pdev,
238 struct vctrl_data *vctrl)
239{
240 int ret;
241 struct device_node *np = pdev->dev.of_node;
242 u32 pval;
243 u32 vrange_ctrl[2];
244
245 ret = of_property_read_u32(np, "ovp-threshold-percent", &pval);
246 if (!ret) {
247 vctrl->ovp_threshold = pval;
248 if (vctrl->ovp_threshold > 100) {
249 dev_err(&pdev->dev,
250 "ovp-threshold-percent (%u) > 100\n",
251 vctrl->ovp_threshold);
252 return -EINVAL;
253 }
254 }
255
256 ret = of_property_read_u32(np, "min-slew-down-rate", &pval);
257 if (!ret) {
258 vctrl->min_slew_down_rate = pval;
259
260 /* We use the value as int and as divider; sanity check */
261 if (vctrl->min_slew_down_rate == 0) {
262 dev_err(&pdev->dev,
263 "min-slew-down-rate must not be 0\n");
264 return -EINVAL;
265 } else if (vctrl->min_slew_down_rate > INT_MAX) {
266 dev_err(&pdev->dev, "min-slew-down-rate (%u) too big\n",
267 vctrl->min_slew_down_rate);
268 return -EINVAL;
269 }
270 }
271
272 if (vctrl->ovp_threshold && !vctrl->min_slew_down_rate) {
273 dev_err(&pdev->dev,
274 "ovp-threshold-percent requires min-slew-down-rate\n");
275 return -EINVAL;
276 }
277
278 ret = of_property_read_u32(np, "regulator-min-microvolt", &pval);
279 if (ret) {
280 dev_err(&pdev->dev,
281 "failed to read regulator-min-microvolt: %d\n", ret);
282 return ret;
283 }
284 vctrl->vrange.out.min_uV = pval;
285
286 ret = of_property_read_u32(np, "regulator-max-microvolt", &pval);
287 if (ret) {
288 dev_err(&pdev->dev,
289 "failed to read regulator-max-microvolt: %d\n", ret);
290 return ret;
291 }
292 vctrl->vrange.out.max_uV = pval;
293
294 ret = of_property_read_u32_array(np, "ctrl-voltage-range", vrange_ctrl,
295 2);
296 if (ret) {
297 dev_err(&pdev->dev, "failed to read ctrl-voltage-range: %d\n",
298 ret);
299 return ret;
300 }
301
302 if (vrange_ctrl[0] >= vrange_ctrl[1]) {
303 dev_err(&pdev->dev, "ctrl-voltage-range is invalid: %d-%d\n",
304 vrange_ctrl[0], vrange_ctrl[1]);
305 return -EINVAL;
306 }
307
308 vctrl->vrange.ctrl.min_uV = vrange_ctrl[0];
309 vctrl->vrange.ctrl.max_uV = vrange_ctrl[1];
310
311 return 0;
312}
313
314static int vctrl_cmp_ctrl_uV(const void *a, const void *b)
315{
316 const struct vctrl_voltage_table *at = a;
317 const struct vctrl_voltage_table *bt = b;
318
319 return at->ctrl - bt->ctrl;
320}
321
322static int vctrl_init_vtable(struct platform_device *pdev,
323 struct regulator *ctrl_reg)
324{
325 struct vctrl_data *vctrl = platform_get_drvdata(pdev);
326 struct regulator_desc *rdesc = &vctrl->desc;
327 struct vctrl_voltage_range *vrange_ctrl = &vctrl->vrange.ctrl;
328 int n_voltages;
329 int ctrl_uV;
330 int i, idx_vt;
331
332 n_voltages = regulator_count_voltages(ctrl_reg);
333
334 rdesc->n_voltages = n_voltages;
335
336 /* determine number of steps within the range of the vctrl regulator */
337 for (i = 0; i < n_voltages; i++) {
338 ctrl_uV = regulator_list_voltage(ctrl_reg, i);
339
340 if (ctrl_uV < vrange_ctrl->min_uV ||
341 ctrl_uV > vrange_ctrl->max_uV)
342 rdesc->n_voltages--;
343 }
344
345 if (rdesc->n_voltages == 0) {
346 dev_err(&pdev->dev, "invalid configuration\n");
347 return -EINVAL;
348 }
349
350 vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages,
351 sizeof(struct vctrl_voltage_table),
352 GFP_KERNEL);
353 if (!vctrl->vtable)
354 return -ENOMEM;
355
356 /* create mapping control <=> output voltage */
357 for (i = 0, idx_vt = 0; i < n_voltages; i++) {
358 ctrl_uV = regulator_list_voltage(ctrl_reg, i);
359
360 if (ctrl_uV < vrange_ctrl->min_uV ||
361 ctrl_uV > vrange_ctrl->max_uV)
362 continue;
363
364 vctrl->vtable[idx_vt].ctrl = ctrl_uV;
365 vctrl->vtable[idx_vt].out =
366 vctrl_calc_output_voltage(vctrl, ctrl_uV);
367 idx_vt++;
368 }
369
370 /* we rely on the table to be ordered by ascending voltage */
371 sort(vctrl->vtable, rdesc->n_voltages,
372 sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV,
373 NULL);
374
375 /* pre-calculate OVP-safe downward transitions */
376 for (i = rdesc->n_voltages - 1; i > 0; i--) {
377 int j;
378 int ovp_min_uV = (vctrl->vtable[i].out *
379 (100 - vctrl->ovp_threshold)) / 100;
380
381 for (j = 0; j < i; j++) {
382 if (vctrl->vtable[j].out >= ovp_min_uV) {
383 vctrl->vtable[i].ovp_min_sel = j;
384 break;
385 }
386 }
387
388 if (j == i) {
389 dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n",
390 vctrl->vtable[i].out);
391 /* use next lowest voltage */
392 vctrl->vtable[i].ovp_min_sel = i - 1;
393 }
394 }
395
396 return 0;
397}
398
399static int vctrl_enable(struct regulator_dev *rdev)
400{
401 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
402
403 vctrl->enabled = true;
404
405 return 0;
406}
407
408static int vctrl_disable(struct regulator_dev *rdev)
409{
410 struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
411
412 vctrl->enabled = false;
413
414 return 0;
415}
416
417static 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
424static 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
432static 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
442static 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 struct regulator *ctrl_reg;
451 int ctrl_uV;
452 int ret;
453
454 vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data),
455 GFP_KERNEL);
456 if (!vctrl)
457 return -ENOMEM;
458
459 platform_set_drvdata(pdev, vctrl);
460
461 ret = vctrl_parse_dt(pdev, vctrl);
462 if (ret)
463 return ret;
464
465 ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl");
466 if (IS_ERR(ctrl_reg))
467 return PTR_ERR(ctrl_reg);
468
469 vrange_ctrl = &vctrl->vrange.ctrl;
470
471 rdesc = &vctrl->desc;
472 rdesc->name = "vctrl";
473 rdesc->type = REGULATOR_VOLTAGE;
474 rdesc->owner = THIS_MODULE;
475 rdesc->supply_name = "ctrl";
476
477 if ((regulator_get_linear_step(ctrl_reg) == 1) ||
478 (regulator_count_voltages(ctrl_reg) == -EINVAL)) {
479 rdesc->continuous_voltage_range = true;
480 rdesc->ops = &vctrl_ops_cont;
481 } else {
482 rdesc->ops = &vctrl_ops_non_cont;
483 }
484
485 init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc);
486 if (!init_data)
487 return -ENOMEM;
488
489 cfg.of_node = np;
490 cfg.dev = &pdev->dev;
491 cfg.driver_data = vctrl;
492 cfg.init_data = init_data;
493
494 if (!rdesc->continuous_voltage_range) {
495 ret = vctrl_init_vtable(pdev, ctrl_reg);
496 if (ret)
497 return ret;
498
499 /* Use locked consumer API when not in regulator framework */
500 ctrl_uV = regulator_get_voltage(ctrl_reg);
501 if (ctrl_uV < 0) {
502 dev_err(&pdev->dev, "failed to get control voltage\n");
503 return ctrl_uV;
504 }
505
506 /* determine current voltage selector from control voltage */
507 if (ctrl_uV < vrange_ctrl->min_uV) {
508 vctrl->sel = 0;
509 } else if (ctrl_uV > vrange_ctrl->max_uV) {
510 vctrl->sel = rdesc->n_voltages - 1;
511 } else {
512 int i;
513
514 for (i = 0; i < rdesc->n_voltages; i++) {
515 if (ctrl_uV == vctrl->vtable[i].ctrl) {
516 vctrl->sel = i;
517 break;
518 }
519 }
520 }
521 }
522
523 /* Drop ctrl-supply here in favor of regulator core managed supply */
524 devm_regulator_put(ctrl_reg);
525
526 vctrl->rdev = devm_regulator_register(&pdev->dev, rdesc, &cfg);
527 if (IS_ERR(vctrl->rdev)) {
528 ret = PTR_ERR(vctrl->rdev);
529 dev_err(&pdev->dev, "failed to register regulator: %d\n", ret);
530 return ret;
531 }
532
533 return 0;
534}
535
536static const struct of_device_id vctrl_of_match[] = {
537 { .compatible = "vctrl-regulator", },
538 {},
539};
540MODULE_DEVICE_TABLE(of, vctrl_of_match);
541
542static struct platform_driver vctrl_driver = {
543 .probe = vctrl_probe,
544 .driver = {
545 .name = "vctrl-regulator",
546 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
547 .of_match_table = of_match_ptr(vctrl_of_match),
548 },
549};
550
551module_platform_driver(vctrl_driver);
552
553MODULE_DESCRIPTION("Voltage Controlled Regulator Driver");
554MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
555MODULE_LICENSE("GPL v2");