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9c92ab61 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
9dee7a72 MK |
2 | /* |
3 | * Driver for voltage controller regulators | |
4 | * | |
5 | * Copyright (C) 2017 Google, Inc. | |
9dee7a72 MK |
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/driver.h> | |
15 | #include <linux/regulator/of_regulator.h> | |
16 | #include <linux/sort.h> | |
17 | ||
18 | struct vctrl_voltage_range { | |
19 | int min_uV; | |
20 | int max_uV; | |
21 | }; | |
22 | ||
23 | struct vctrl_voltage_ranges { | |
24 | struct vctrl_voltage_range ctrl; | |
25 | struct vctrl_voltage_range out; | |
26 | }; | |
27 | ||
28 | struct vctrl_voltage_table { | |
29 | int ctrl; | |
30 | int out; | |
31 | int ovp_min_sel; | |
32 | }; | |
33 | ||
34 | struct vctrl_data { | |
35 | struct regulator_dev *rdev; | |
36 | struct regulator_desc desc; | |
37 | struct regulator *ctrl_reg; | |
38 | bool enabled; | |
39 | unsigned int min_slew_down_rate; | |
40 | unsigned int ovp_threshold; | |
41 | struct vctrl_voltage_ranges vrange; | |
42 | struct vctrl_voltage_table *vtable; | |
43 | unsigned int sel; | |
44 | }; | |
45 | ||
46 | static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV) | |
47 | { | |
48 | struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl; | |
49 | struct vctrl_voltage_range *out = &vctrl->vrange.out; | |
50 | ||
51 | return ctrl->min_uV + | |
52 | DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) * | |
53 | (ctrl->max_uV - ctrl->min_uV), | |
54 | out->max_uV - out->min_uV); | |
55 | } | |
56 | ||
57 | static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV) | |
58 | { | |
59 | struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl; | |
60 | struct vctrl_voltage_range *out = &vctrl->vrange.out; | |
61 | ||
62 | if (ctrl_uV < 0) { | |
63 | pr_err("vctrl: failed to get control voltage\n"); | |
64 | return ctrl_uV; | |
65 | } | |
66 | ||
67 | if (ctrl_uV < ctrl->min_uV) | |
68 | return out->min_uV; | |
69 | ||
70 | if (ctrl_uV > ctrl->max_uV) | |
71 | return out->max_uV; | |
72 | ||
73 | return out->min_uV + | |
74 | DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) * | |
75 | (out->max_uV - out->min_uV), | |
76 | ctrl->max_uV - ctrl->min_uV); | |
77 | } | |
78 | ||
79 | static int vctrl_get_voltage(struct regulator_dev *rdev) | |
80 | { | |
81 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
82 | int ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg); | |
83 | ||
84 | return vctrl_calc_output_voltage(vctrl, ctrl_uV); | |
85 | } | |
86 | ||
87 | static int vctrl_set_voltage(struct regulator_dev *rdev, | |
88 | int req_min_uV, int req_max_uV, | |
89 | unsigned int *selector) | |
90 | { | |
91 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
92 | struct regulator *ctrl_reg = vctrl->ctrl_reg; | |
93 | int orig_ctrl_uV = regulator_get_voltage(ctrl_reg); | |
94 | int uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV); | |
95 | int ret; | |
96 | ||
97 | if (req_min_uV >= uV || !vctrl->ovp_threshold) | |
98 | /* voltage rising or no OVP */ | |
99 | return regulator_set_voltage( | |
100 | ctrl_reg, | |
101 | vctrl_calc_ctrl_voltage(vctrl, req_min_uV), | |
102 | vctrl_calc_ctrl_voltage(vctrl, req_max_uV)); | |
103 | ||
104 | while (uV > req_min_uV) { | |
105 | int max_drop_uV = (uV * vctrl->ovp_threshold) / 100; | |
106 | int next_uV; | |
107 | int next_ctrl_uV; | |
108 | int delay; | |
109 | ||
110 | /* Make sure no infinite loop even in crazy cases */ | |
111 | if (max_drop_uV == 0) | |
112 | max_drop_uV = 1; | |
113 | ||
114 | next_uV = max_t(int, req_min_uV, uV - max_drop_uV); | |
115 | next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV); | |
116 | ||
117 | ret = regulator_set_voltage(ctrl_reg, | |
118 | next_ctrl_uV, | |
119 | next_ctrl_uV); | |
120 | if (ret) | |
121 | goto err; | |
122 | ||
123 | delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate); | |
124 | usleep_range(delay, delay + DIV_ROUND_UP(delay, 10)); | |
125 | ||
126 | uV = next_uV; | |
127 | } | |
128 | ||
129 | return 0; | |
130 | ||
131 | err: | |
132 | /* Try to go back to original voltage */ | |
133 | regulator_set_voltage(ctrl_reg, orig_ctrl_uV, orig_ctrl_uV); | |
134 | ||
135 | return ret; | |
136 | } | |
137 | ||
138 | static int vctrl_get_voltage_sel(struct regulator_dev *rdev) | |
139 | { | |
140 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
141 | ||
142 | return vctrl->sel; | |
143 | } | |
144 | ||
145 | static int vctrl_set_voltage_sel(struct regulator_dev *rdev, | |
146 | unsigned int selector) | |
147 | { | |
148 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
149 | struct regulator *ctrl_reg = vctrl->ctrl_reg; | |
150 | unsigned int orig_sel = vctrl->sel; | |
151 | int ret; | |
152 | ||
153 | if (selector >= rdev->desc->n_voltages) | |
154 | return -EINVAL; | |
155 | ||
156 | if (selector >= vctrl->sel || !vctrl->ovp_threshold) { | |
157 | /* voltage rising or no OVP */ | |
158 | ret = regulator_set_voltage(ctrl_reg, | |
159 | vctrl->vtable[selector].ctrl, | |
160 | vctrl->vtable[selector].ctrl); | |
161 | if (!ret) | |
162 | vctrl->sel = selector; | |
163 | ||
164 | return ret; | |
165 | } | |
166 | ||
167 | while (vctrl->sel != selector) { | |
168 | unsigned int next_sel; | |
169 | int delay; | |
170 | ||
171 | if (selector >= vctrl->vtable[vctrl->sel].ovp_min_sel) | |
172 | next_sel = selector; | |
173 | else | |
174 | next_sel = vctrl->vtable[vctrl->sel].ovp_min_sel; | |
175 | ||
176 | ret = regulator_set_voltage(ctrl_reg, | |
177 | vctrl->vtable[next_sel].ctrl, | |
178 | vctrl->vtable[next_sel].ctrl); | |
179 | if (ret) { | |
180 | dev_err(&rdev->dev, | |
181 | "failed to set control voltage to %duV\n", | |
182 | vctrl->vtable[next_sel].ctrl); | |
183 | goto err; | |
184 | } | |
185 | vctrl->sel = next_sel; | |
186 | ||
187 | delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out - | |
188 | vctrl->vtable[next_sel].out, | |
189 | vctrl->min_slew_down_rate); | |
190 | usleep_range(delay, delay + DIV_ROUND_UP(delay, 10)); | |
191 | } | |
192 | ||
193 | return 0; | |
194 | ||
195 | err: | |
196 | if (vctrl->sel != orig_sel) { | |
197 | /* Try to go back to original voltage */ | |
198 | if (!regulator_set_voltage(ctrl_reg, | |
199 | vctrl->vtable[orig_sel].ctrl, | |
200 | vctrl->vtable[orig_sel].ctrl)) | |
201 | vctrl->sel = orig_sel; | |
202 | else | |
203 | dev_warn(&rdev->dev, | |
204 | "failed to restore original voltage\n"); | |
205 | } | |
206 | ||
207 | return ret; | |
208 | } | |
209 | ||
210 | static int vctrl_list_voltage(struct regulator_dev *rdev, | |
211 | unsigned int selector) | |
212 | { | |
213 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
214 | ||
215 | if (selector >= rdev->desc->n_voltages) | |
216 | return -EINVAL; | |
217 | ||
218 | return vctrl->vtable[selector].out; | |
219 | } | |
220 | ||
221 | static int vctrl_parse_dt(struct platform_device *pdev, | |
222 | struct vctrl_data *vctrl) | |
223 | { | |
224 | int ret; | |
225 | struct device_node *np = pdev->dev.of_node; | |
226 | u32 pval; | |
227 | u32 vrange_ctrl[2]; | |
228 | ||
229 | vctrl->ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl"); | |
230 | if (IS_ERR(vctrl->ctrl_reg)) | |
231 | return PTR_ERR(vctrl->ctrl_reg); | |
232 | ||
233 | ret = of_property_read_u32(np, "ovp-threshold-percent", &pval); | |
234 | if (!ret) { | |
235 | vctrl->ovp_threshold = pval; | |
236 | if (vctrl->ovp_threshold > 100) { | |
237 | dev_err(&pdev->dev, | |
238 | "ovp-threshold-percent (%u) > 100\n", | |
239 | vctrl->ovp_threshold); | |
240 | return -EINVAL; | |
241 | } | |
242 | } | |
243 | ||
244 | ret = of_property_read_u32(np, "min-slew-down-rate", &pval); | |
245 | if (!ret) { | |
246 | vctrl->min_slew_down_rate = pval; | |
247 | ||
248 | /* We use the value as int and as divider; sanity check */ | |
249 | if (vctrl->min_slew_down_rate == 0) { | |
250 | dev_err(&pdev->dev, | |
251 | "min-slew-down-rate must not be 0\n"); | |
252 | return -EINVAL; | |
253 | } else if (vctrl->min_slew_down_rate > INT_MAX) { | |
254 | dev_err(&pdev->dev, "min-slew-down-rate (%u) too big\n", | |
255 | vctrl->min_slew_down_rate); | |
256 | return -EINVAL; | |
257 | } | |
258 | } | |
259 | ||
260 | if (vctrl->ovp_threshold && !vctrl->min_slew_down_rate) { | |
261 | dev_err(&pdev->dev, | |
262 | "ovp-threshold-percent requires min-slew-down-rate\n"); | |
263 | return -EINVAL; | |
264 | } | |
265 | ||
266 | ret = of_property_read_u32(np, "regulator-min-microvolt", &pval); | |
267 | if (ret) { | |
268 | dev_err(&pdev->dev, | |
269 | "failed to read regulator-min-microvolt: %d\n", ret); | |
270 | return ret; | |
271 | } | |
272 | vctrl->vrange.out.min_uV = pval; | |
273 | ||
274 | ret = of_property_read_u32(np, "regulator-max-microvolt", &pval); | |
275 | if (ret) { | |
276 | dev_err(&pdev->dev, | |
277 | "failed to read regulator-max-microvolt: %d\n", ret); | |
278 | return ret; | |
279 | } | |
280 | vctrl->vrange.out.max_uV = pval; | |
281 | ||
282 | ret = of_property_read_u32_array(np, "ctrl-voltage-range", vrange_ctrl, | |
283 | 2); | |
284 | if (ret) { | |
285 | dev_err(&pdev->dev, "failed to read ctrl-voltage-range: %d\n", | |
286 | ret); | |
287 | return ret; | |
288 | } | |
289 | ||
290 | if (vrange_ctrl[0] >= vrange_ctrl[1]) { | |
291 | dev_err(&pdev->dev, "ctrl-voltage-range is invalid: %d-%d\n", | |
292 | vrange_ctrl[0], vrange_ctrl[1]); | |
293 | return -EINVAL; | |
294 | } | |
295 | ||
296 | vctrl->vrange.ctrl.min_uV = vrange_ctrl[0]; | |
297 | vctrl->vrange.ctrl.max_uV = vrange_ctrl[1]; | |
298 | ||
299 | return 0; | |
300 | } | |
301 | ||
302 | static int vctrl_cmp_ctrl_uV(const void *a, const void *b) | |
303 | { | |
304 | const struct vctrl_voltage_table *at = a; | |
305 | const struct vctrl_voltage_table *bt = b; | |
306 | ||
307 | return at->ctrl - bt->ctrl; | |
308 | } | |
309 | ||
310 | static int vctrl_init_vtable(struct platform_device *pdev) | |
311 | { | |
312 | struct vctrl_data *vctrl = platform_get_drvdata(pdev); | |
313 | struct regulator_desc *rdesc = &vctrl->desc; | |
314 | struct regulator *ctrl_reg = vctrl->ctrl_reg; | |
315 | struct vctrl_voltage_range *vrange_ctrl = &vctrl->vrange.ctrl; | |
316 | int n_voltages; | |
317 | int ctrl_uV; | |
318 | int i, idx_vt; | |
319 | ||
320 | n_voltages = regulator_count_voltages(ctrl_reg); | |
321 | ||
322 | rdesc->n_voltages = n_voltages; | |
323 | ||
324 | /* determine number of steps within the range of the vctrl regulator */ | |
325 | for (i = 0; i < n_voltages; i++) { | |
326 | ctrl_uV = regulator_list_voltage(ctrl_reg, i); | |
327 | ||
328 | if (ctrl_uV < vrange_ctrl->min_uV || | |
9e488c0a | 329 | ctrl_uV > vrange_ctrl->max_uV) |
9dee7a72 | 330 | rdesc->n_voltages--; |
9dee7a72 MK |
331 | } |
332 | ||
333 | if (rdesc->n_voltages == 0) { | |
334 | dev_err(&pdev->dev, "invalid configuration\n"); | |
335 | return -EINVAL; | |
336 | } | |
337 | ||
a9bbb453 AL |
338 | vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages, |
339 | sizeof(struct vctrl_voltage_table), | |
340 | GFP_KERNEL); | |
9dee7a72 MK |
341 | if (!vctrl->vtable) |
342 | return -ENOMEM; | |
343 | ||
344 | /* create mapping control <=> output voltage */ | |
345 | for (i = 0, idx_vt = 0; i < n_voltages; i++) { | |
346 | ctrl_uV = regulator_list_voltage(ctrl_reg, i); | |
347 | ||
348 | if (ctrl_uV < vrange_ctrl->min_uV || | |
349 | ctrl_uV > vrange_ctrl->max_uV) | |
350 | continue; | |
351 | ||
352 | vctrl->vtable[idx_vt].ctrl = ctrl_uV; | |
353 | vctrl->vtable[idx_vt].out = | |
354 | vctrl_calc_output_voltage(vctrl, ctrl_uV); | |
355 | idx_vt++; | |
356 | } | |
357 | ||
358 | /* we rely on the table to be ordered by ascending voltage */ | |
359 | sort(vctrl->vtable, rdesc->n_voltages, | |
360 | sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV, | |
361 | NULL); | |
362 | ||
363 | /* pre-calculate OVP-safe downward transitions */ | |
a9bbb453 | 364 | for (i = rdesc->n_voltages - 1; i > 0; i--) { |
9dee7a72 MK |
365 | int j; |
366 | int ovp_min_uV = (vctrl->vtable[i].out * | |
367 | (100 - vctrl->ovp_threshold)) / 100; | |
368 | ||
369 | for (j = 0; j < i; j++) { | |
370 | if (vctrl->vtable[j].out >= ovp_min_uV) { | |
371 | vctrl->vtable[i].ovp_min_sel = j; | |
372 | break; | |
373 | } | |
374 | } | |
375 | ||
376 | if (j == i) { | |
377 | dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n", | |
378 | vctrl->vtable[i].out); | |
379 | /* use next lowest voltage */ | |
380 | vctrl->vtable[i].ovp_min_sel = i - 1; | |
381 | } | |
382 | } | |
383 | ||
384 | return 0; | |
385 | } | |
386 | ||
387 | static int vctrl_enable(struct regulator_dev *rdev) | |
388 | { | |
389 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
390 | int ret = regulator_enable(vctrl->ctrl_reg); | |
391 | ||
392 | if (!ret) | |
393 | vctrl->enabled = true; | |
394 | ||
395 | return ret; | |
396 | } | |
397 | ||
398 | static int vctrl_disable(struct regulator_dev *rdev) | |
399 | { | |
400 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
401 | int ret = regulator_disable(vctrl->ctrl_reg); | |
402 | ||
403 | if (!ret) | |
404 | vctrl->enabled = false; | |
405 | ||
406 | return ret; | |
407 | } | |
408 | ||
409 | static int vctrl_is_enabled(struct regulator_dev *rdev) | |
410 | { | |
411 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
412 | ||
413 | return vctrl->enabled; | |
414 | } | |
415 | ||
416 | static const struct regulator_ops vctrl_ops_cont = { | |
417 | .enable = vctrl_enable, | |
418 | .disable = vctrl_disable, | |
419 | .is_enabled = vctrl_is_enabled, | |
420 | .get_voltage = vctrl_get_voltage, | |
421 | .set_voltage = vctrl_set_voltage, | |
422 | }; | |
423 | ||
424 | static const struct regulator_ops vctrl_ops_non_cont = { | |
425 | .enable = vctrl_enable, | |
426 | .disable = vctrl_disable, | |
427 | .is_enabled = vctrl_is_enabled, | |
428 | .set_voltage_sel = vctrl_set_voltage_sel, | |
429 | .get_voltage_sel = vctrl_get_voltage_sel, | |
430 | .list_voltage = vctrl_list_voltage, | |
431 | .map_voltage = regulator_map_voltage_iterate, | |
432 | }; | |
433 | ||
434 | static int vctrl_probe(struct platform_device *pdev) | |
435 | { | |
436 | struct device_node *np = pdev->dev.of_node; | |
437 | struct vctrl_data *vctrl; | |
438 | const struct regulator_init_data *init_data; | |
439 | struct regulator_desc *rdesc; | |
440 | struct regulator_config cfg = { }; | |
441 | struct vctrl_voltage_range *vrange_ctrl; | |
442 | int ctrl_uV; | |
443 | int ret; | |
444 | ||
445 | vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data), | |
446 | GFP_KERNEL); | |
447 | if (!vctrl) | |
448 | return -ENOMEM; | |
449 | ||
450 | platform_set_drvdata(pdev, vctrl); | |
451 | ||
452 | ret = vctrl_parse_dt(pdev, vctrl); | |
453 | if (ret) | |
454 | return ret; | |
455 | ||
456 | vrange_ctrl = &vctrl->vrange.ctrl; | |
457 | ||
458 | rdesc = &vctrl->desc; | |
459 | rdesc->name = "vctrl"; | |
460 | rdesc->type = REGULATOR_VOLTAGE; | |
461 | rdesc->owner = THIS_MODULE; | |
462 | ||
463 | if ((regulator_get_linear_step(vctrl->ctrl_reg) == 1) || | |
464 | (regulator_count_voltages(vctrl->ctrl_reg) == -EINVAL)) { | |
465 | rdesc->continuous_voltage_range = true; | |
466 | rdesc->ops = &vctrl_ops_cont; | |
467 | } else { | |
468 | rdesc->ops = &vctrl_ops_non_cont; | |
469 | } | |
470 | ||
471 | init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc); | |
472 | if (!init_data) | |
473 | return -ENOMEM; | |
474 | ||
475 | cfg.of_node = np; | |
476 | cfg.dev = &pdev->dev; | |
477 | cfg.driver_data = vctrl; | |
478 | cfg.init_data = init_data; | |
479 | ||
480 | if (!rdesc->continuous_voltage_range) { | |
481 | ret = vctrl_init_vtable(pdev); | |
482 | if (ret) | |
483 | return ret; | |
484 | ||
485 | ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg); | |
486 | if (ctrl_uV < 0) { | |
487 | dev_err(&pdev->dev, "failed to get control voltage\n"); | |
488 | return ctrl_uV; | |
489 | } | |
490 | ||
491 | /* determine current voltage selector from control voltage */ | |
492 | if (ctrl_uV < vrange_ctrl->min_uV) { | |
493 | vctrl->sel = 0; | |
494 | } else if (ctrl_uV > vrange_ctrl->max_uV) { | |
495 | vctrl->sel = rdesc->n_voltages - 1; | |
496 | } else { | |
497 | int i; | |
498 | ||
499 | for (i = 0; i < rdesc->n_voltages; i++) { | |
500 | if (ctrl_uV == vctrl->vtable[i].ctrl) { | |
501 | vctrl->sel = i; | |
502 | break; | |
503 | } | |
504 | } | |
505 | } | |
506 | } | |
507 | ||
508 | vctrl->rdev = devm_regulator_register(&pdev->dev, rdesc, &cfg); | |
509 | if (IS_ERR(vctrl->rdev)) { | |
510 | ret = PTR_ERR(vctrl->rdev); | |
511 | dev_err(&pdev->dev, "failed to register regulator: %d\n", ret); | |
512 | return ret; | |
513 | } | |
514 | ||
515 | return 0; | |
516 | } | |
517 | ||
518 | static const struct of_device_id vctrl_of_match[] = { | |
519 | { .compatible = "vctrl-regulator", }, | |
520 | {}, | |
521 | }; | |
522 | MODULE_DEVICE_TABLE(of, vctrl_of_match); | |
523 | ||
524 | static struct platform_driver vctrl_driver = { | |
525 | .probe = vctrl_probe, | |
526 | .driver = { | |
527 | .name = "vctrl-regulator", | |
528 | .of_match_table = of_match_ptr(vctrl_of_match), | |
529 | }, | |
530 | }; | |
531 | ||
532 | module_platform_driver(vctrl_driver); | |
533 | ||
534 | MODULE_DESCRIPTION("Voltage Controlled Regulator Driver"); | |
535 | MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>"); | |
536 | MODULE_LICENSE("GPL v2"); |