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9dee7a72 MK |
1 | /* |
2 | * Driver for voltage controller regulators | |
3 | * | |
4 | * Copyright (C) 2017 Google, Inc. | |
5 | * | |
6 | * This software is licensed under the terms of the GNU General Public | |
7 | * License version 2, as published by the Free Software Foundation, and | |
8 | * may be copied, distributed, and modified under those terms. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | */ | |
15 | ||
16 | #include <linux/delay.h> | |
17 | #include <linux/err.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/of.h> | |
21 | #include <linux/of_device.h> | |
22 | #include <linux/regulator/driver.h> | |
23 | #include <linux/regulator/of_regulator.h> | |
24 | #include <linux/sort.h> | |
25 | ||
26 | struct vctrl_voltage_range { | |
27 | int min_uV; | |
28 | int max_uV; | |
29 | }; | |
30 | ||
31 | struct vctrl_voltage_ranges { | |
32 | struct vctrl_voltage_range ctrl; | |
33 | struct vctrl_voltage_range out; | |
34 | }; | |
35 | ||
36 | struct vctrl_voltage_table { | |
37 | int ctrl; | |
38 | int out; | |
39 | int ovp_min_sel; | |
40 | }; | |
41 | ||
42 | struct vctrl_data { | |
43 | struct regulator_dev *rdev; | |
44 | struct regulator_desc desc; | |
45 | struct regulator *ctrl_reg; | |
46 | bool enabled; | |
47 | unsigned int min_slew_down_rate; | |
48 | unsigned int ovp_threshold; | |
49 | struct vctrl_voltage_ranges vrange; | |
50 | struct vctrl_voltage_table *vtable; | |
51 | unsigned int sel; | |
52 | }; | |
53 | ||
54 | static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV) | |
55 | { | |
56 | struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl; | |
57 | struct vctrl_voltage_range *out = &vctrl->vrange.out; | |
58 | ||
59 | return ctrl->min_uV + | |
60 | DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) * | |
61 | (ctrl->max_uV - ctrl->min_uV), | |
62 | out->max_uV - out->min_uV); | |
63 | } | |
64 | ||
65 | static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV) | |
66 | { | |
67 | struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl; | |
68 | struct vctrl_voltage_range *out = &vctrl->vrange.out; | |
69 | ||
70 | if (ctrl_uV < 0) { | |
71 | pr_err("vctrl: failed to get control voltage\n"); | |
72 | return ctrl_uV; | |
73 | } | |
74 | ||
75 | if (ctrl_uV < ctrl->min_uV) | |
76 | return out->min_uV; | |
77 | ||
78 | if (ctrl_uV > ctrl->max_uV) | |
79 | return out->max_uV; | |
80 | ||
81 | return out->min_uV + | |
82 | DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) * | |
83 | (out->max_uV - out->min_uV), | |
84 | ctrl->max_uV - ctrl->min_uV); | |
85 | } | |
86 | ||
87 | static int vctrl_get_voltage(struct regulator_dev *rdev) | |
88 | { | |
89 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
90 | int ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg); | |
91 | ||
92 | return vctrl_calc_output_voltage(vctrl, ctrl_uV); | |
93 | } | |
94 | ||
95 | static int vctrl_set_voltage(struct regulator_dev *rdev, | |
96 | int req_min_uV, int req_max_uV, | |
97 | unsigned int *selector) | |
98 | { | |
99 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
100 | struct regulator *ctrl_reg = vctrl->ctrl_reg; | |
101 | int orig_ctrl_uV = regulator_get_voltage(ctrl_reg); | |
102 | int uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV); | |
103 | int ret; | |
104 | ||
105 | if (req_min_uV >= uV || !vctrl->ovp_threshold) | |
106 | /* voltage rising or no OVP */ | |
107 | return regulator_set_voltage( | |
108 | ctrl_reg, | |
109 | vctrl_calc_ctrl_voltage(vctrl, req_min_uV), | |
110 | vctrl_calc_ctrl_voltage(vctrl, req_max_uV)); | |
111 | ||
112 | while (uV > req_min_uV) { | |
113 | int max_drop_uV = (uV * vctrl->ovp_threshold) / 100; | |
114 | int next_uV; | |
115 | int next_ctrl_uV; | |
116 | int delay; | |
117 | ||
118 | /* Make sure no infinite loop even in crazy cases */ | |
119 | if (max_drop_uV == 0) | |
120 | max_drop_uV = 1; | |
121 | ||
122 | next_uV = max_t(int, req_min_uV, uV - max_drop_uV); | |
123 | next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV); | |
124 | ||
125 | ret = regulator_set_voltage(ctrl_reg, | |
126 | next_ctrl_uV, | |
127 | next_ctrl_uV); | |
128 | if (ret) | |
129 | goto err; | |
130 | ||
131 | delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate); | |
132 | usleep_range(delay, delay + DIV_ROUND_UP(delay, 10)); | |
133 | ||
134 | uV = next_uV; | |
135 | } | |
136 | ||
137 | return 0; | |
138 | ||
139 | err: | |
140 | /* Try to go back to original voltage */ | |
141 | regulator_set_voltage(ctrl_reg, orig_ctrl_uV, orig_ctrl_uV); | |
142 | ||
143 | return ret; | |
144 | } | |
145 | ||
146 | static int vctrl_get_voltage_sel(struct regulator_dev *rdev) | |
147 | { | |
148 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
149 | ||
150 | return vctrl->sel; | |
151 | } | |
152 | ||
153 | static int vctrl_set_voltage_sel(struct regulator_dev *rdev, | |
154 | unsigned int selector) | |
155 | { | |
156 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
157 | struct regulator *ctrl_reg = vctrl->ctrl_reg; | |
158 | unsigned int orig_sel = vctrl->sel; | |
159 | int ret; | |
160 | ||
161 | if (selector >= rdev->desc->n_voltages) | |
162 | return -EINVAL; | |
163 | ||
164 | if (selector >= vctrl->sel || !vctrl->ovp_threshold) { | |
165 | /* voltage rising or no OVP */ | |
166 | ret = regulator_set_voltage(ctrl_reg, | |
167 | vctrl->vtable[selector].ctrl, | |
168 | vctrl->vtable[selector].ctrl); | |
169 | if (!ret) | |
170 | vctrl->sel = selector; | |
171 | ||
172 | return ret; | |
173 | } | |
174 | ||
175 | while (vctrl->sel != selector) { | |
176 | unsigned int next_sel; | |
177 | int delay; | |
178 | ||
179 | if (selector >= vctrl->vtable[vctrl->sel].ovp_min_sel) | |
180 | next_sel = selector; | |
181 | else | |
182 | next_sel = vctrl->vtable[vctrl->sel].ovp_min_sel; | |
183 | ||
184 | ret = regulator_set_voltage(ctrl_reg, | |
185 | vctrl->vtable[next_sel].ctrl, | |
186 | vctrl->vtable[next_sel].ctrl); | |
187 | if (ret) { | |
188 | dev_err(&rdev->dev, | |
189 | "failed to set control voltage to %duV\n", | |
190 | vctrl->vtable[next_sel].ctrl); | |
191 | goto err; | |
192 | } | |
193 | vctrl->sel = next_sel; | |
194 | ||
195 | delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out - | |
196 | vctrl->vtable[next_sel].out, | |
197 | vctrl->min_slew_down_rate); | |
198 | usleep_range(delay, delay + DIV_ROUND_UP(delay, 10)); | |
199 | } | |
200 | ||
201 | return 0; | |
202 | ||
203 | err: | |
204 | if (vctrl->sel != orig_sel) { | |
205 | /* Try to go back to original voltage */ | |
206 | if (!regulator_set_voltage(ctrl_reg, | |
207 | vctrl->vtable[orig_sel].ctrl, | |
208 | vctrl->vtable[orig_sel].ctrl)) | |
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 | ||
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 | ||
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 | ||
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 | ||
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 | continue; | |
340 | } | |
341 | } | |
342 | ||
343 | if (rdesc->n_voltages == 0) { | |
344 | dev_err(&pdev->dev, "invalid configuration\n"); | |
345 | return -EINVAL; | |
346 | } | |
347 | ||
a9bbb453 AL |
348 | vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages, |
349 | sizeof(struct vctrl_voltage_table), | |
350 | GFP_KERNEL); | |
9dee7a72 MK |
351 | if (!vctrl->vtable) |
352 | return -ENOMEM; | |
353 | ||
354 | /* create mapping control <=> output voltage */ | |
355 | for (i = 0, idx_vt = 0; i < n_voltages; i++) { | |
356 | ctrl_uV = regulator_list_voltage(ctrl_reg, i); | |
357 | ||
358 | if (ctrl_uV < vrange_ctrl->min_uV || | |
359 | ctrl_uV > vrange_ctrl->max_uV) | |
360 | continue; | |
361 | ||
362 | vctrl->vtable[idx_vt].ctrl = ctrl_uV; | |
363 | vctrl->vtable[idx_vt].out = | |
364 | vctrl_calc_output_voltage(vctrl, ctrl_uV); | |
365 | idx_vt++; | |
366 | } | |
367 | ||
368 | /* we rely on the table to be ordered by ascending voltage */ | |
369 | sort(vctrl->vtable, rdesc->n_voltages, | |
370 | sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV, | |
371 | NULL); | |
372 | ||
373 | /* pre-calculate OVP-safe downward transitions */ | |
a9bbb453 | 374 | for (i = rdesc->n_voltages - 1; i > 0; i--) { |
9dee7a72 MK |
375 | int j; |
376 | int ovp_min_uV = (vctrl->vtable[i].out * | |
377 | (100 - vctrl->ovp_threshold)) / 100; | |
378 | ||
379 | for (j = 0; j < i; j++) { | |
380 | if (vctrl->vtable[j].out >= ovp_min_uV) { | |
381 | vctrl->vtable[i].ovp_min_sel = j; | |
382 | break; | |
383 | } | |
384 | } | |
385 | ||
386 | if (j == i) { | |
387 | dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n", | |
388 | vctrl->vtable[i].out); | |
389 | /* use next lowest voltage */ | |
390 | vctrl->vtable[i].ovp_min_sel = i - 1; | |
391 | } | |
392 | } | |
393 | ||
394 | return 0; | |
395 | } | |
396 | ||
397 | static int vctrl_enable(struct regulator_dev *rdev) | |
398 | { | |
399 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
400 | int ret = regulator_enable(vctrl->ctrl_reg); | |
401 | ||
402 | if (!ret) | |
403 | vctrl->enabled = true; | |
404 | ||
405 | return ret; | |
406 | } | |
407 | ||
408 | static int vctrl_disable(struct regulator_dev *rdev) | |
409 | { | |
410 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
411 | int ret = regulator_disable(vctrl->ctrl_reg); | |
412 | ||
413 | if (!ret) | |
414 | vctrl->enabled = false; | |
415 | ||
416 | return ret; | |
417 | } | |
418 | ||
419 | static int vctrl_is_enabled(struct regulator_dev *rdev) | |
420 | { | |
421 | struct vctrl_data *vctrl = rdev_get_drvdata(rdev); | |
422 | ||
423 | return vctrl->enabled; | |
424 | } | |
425 | ||
426 | static const struct regulator_ops vctrl_ops_cont = { | |
427 | .enable = vctrl_enable, | |
428 | .disable = vctrl_disable, | |
429 | .is_enabled = vctrl_is_enabled, | |
430 | .get_voltage = vctrl_get_voltage, | |
431 | .set_voltage = vctrl_set_voltage, | |
432 | }; | |
433 | ||
434 | static const struct regulator_ops vctrl_ops_non_cont = { | |
435 | .enable = vctrl_enable, | |
436 | .disable = vctrl_disable, | |
437 | .is_enabled = vctrl_is_enabled, | |
438 | .set_voltage_sel = vctrl_set_voltage_sel, | |
439 | .get_voltage_sel = vctrl_get_voltage_sel, | |
440 | .list_voltage = vctrl_list_voltage, | |
441 | .map_voltage = regulator_map_voltage_iterate, | |
442 | }; | |
443 | ||
444 | static int vctrl_probe(struct platform_device *pdev) | |
445 | { | |
446 | struct device_node *np = pdev->dev.of_node; | |
447 | struct vctrl_data *vctrl; | |
448 | const struct regulator_init_data *init_data; | |
449 | struct regulator_desc *rdesc; | |
450 | struct regulator_config cfg = { }; | |
451 | struct vctrl_voltage_range *vrange_ctrl; | |
452 | int ctrl_uV; | |
453 | int ret; | |
454 | ||
455 | vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data), | |
456 | GFP_KERNEL); | |
457 | if (!vctrl) | |
458 | return -ENOMEM; | |
459 | ||
460 | platform_set_drvdata(pdev, vctrl); | |
461 | ||
462 | ret = vctrl_parse_dt(pdev, vctrl); | |
463 | if (ret) | |
464 | return ret; | |
465 | ||
466 | vrange_ctrl = &vctrl->vrange.ctrl; | |
467 | ||
468 | rdesc = &vctrl->desc; | |
469 | rdesc->name = "vctrl"; | |
470 | rdesc->type = REGULATOR_VOLTAGE; | |
471 | rdesc->owner = THIS_MODULE; | |
472 | ||
473 | if ((regulator_get_linear_step(vctrl->ctrl_reg) == 1) || | |
474 | (regulator_count_voltages(vctrl->ctrl_reg) == -EINVAL)) { | |
475 | rdesc->continuous_voltage_range = true; | |
476 | rdesc->ops = &vctrl_ops_cont; | |
477 | } else { | |
478 | rdesc->ops = &vctrl_ops_non_cont; | |
479 | } | |
480 | ||
481 | init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc); | |
482 | if (!init_data) | |
483 | return -ENOMEM; | |
484 | ||
485 | cfg.of_node = np; | |
486 | cfg.dev = &pdev->dev; | |
487 | cfg.driver_data = vctrl; | |
488 | cfg.init_data = init_data; | |
489 | ||
490 | if (!rdesc->continuous_voltage_range) { | |
491 | ret = vctrl_init_vtable(pdev); | |
492 | if (ret) | |
493 | return ret; | |
494 | ||
495 | ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg); | |
496 | if (ctrl_uV < 0) { | |
497 | dev_err(&pdev->dev, "failed to get control voltage\n"); | |
498 | return ctrl_uV; | |
499 | } | |
500 | ||
501 | /* determine current voltage selector from control voltage */ | |
502 | if (ctrl_uV < vrange_ctrl->min_uV) { | |
503 | vctrl->sel = 0; | |
504 | } else if (ctrl_uV > vrange_ctrl->max_uV) { | |
505 | vctrl->sel = rdesc->n_voltages - 1; | |
506 | } else { | |
507 | int i; | |
508 | ||
509 | for (i = 0; i < rdesc->n_voltages; i++) { | |
510 | if (ctrl_uV == vctrl->vtable[i].ctrl) { | |
511 | vctrl->sel = i; | |
512 | break; | |
513 | } | |
514 | } | |
515 | } | |
516 | } | |
517 | ||
518 | vctrl->rdev = devm_regulator_register(&pdev->dev, rdesc, &cfg); | |
519 | if (IS_ERR(vctrl->rdev)) { | |
520 | ret = PTR_ERR(vctrl->rdev); | |
521 | dev_err(&pdev->dev, "failed to register regulator: %d\n", ret); | |
522 | return ret; | |
523 | } | |
524 | ||
525 | return 0; | |
526 | } | |
527 | ||
528 | static const struct of_device_id vctrl_of_match[] = { | |
529 | { .compatible = "vctrl-regulator", }, | |
530 | {}, | |
531 | }; | |
532 | MODULE_DEVICE_TABLE(of, vctrl_of_match); | |
533 | ||
534 | static struct platform_driver vctrl_driver = { | |
535 | .probe = vctrl_probe, | |
536 | .driver = { | |
537 | .name = "vctrl-regulator", | |
538 | .of_match_table = of_match_ptr(vctrl_of_match), | |
539 | }, | |
540 | }; | |
541 | ||
542 | module_platform_driver(vctrl_driver); | |
543 | ||
544 | MODULE_DESCRIPTION("Voltage Controlled Regulator Driver"); | |
545 | MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>"); | |
546 | MODULE_LICENSE("GPL v2"); |