aboutsummaryrefslogtreecommitdiff
path: root/drivers/regulator/vctrl-regulator.c
blob: cbadb1c9967906e99aa34157374aae8e432ebb53 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for voltage controller regulators
 *
 * Copyright (C) 2017 Google, Inc.
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/regulator/coupler.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>
#include <linux/sort.h>

#include "internal.h"

struct vctrl_voltage_range {
	int min_uV;
	int max_uV;
};

struct vctrl_voltage_ranges {
	struct vctrl_voltage_range ctrl;
	struct vctrl_voltage_range out;
};

struct vctrl_voltage_table {
	int ctrl;
	int out;
	int ovp_min_sel;
};

struct vctrl_data {
	struct regulator_dev *rdev;
	struct regulator_desc desc;
	struct regulator *ctrl_reg;
	bool enabled;
	unsigned int min_slew_down_rate;
	unsigned int ovp_threshold;
	struct vctrl_voltage_ranges vrange;
	struct vctrl_voltage_table *vtable;
	unsigned int sel;
};

static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV)
{
	struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
	struct vctrl_voltage_range *out = &vctrl->vrange.out;

	return ctrl->min_uV +
		DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) *
				      (ctrl->max_uV - ctrl->min_uV),
				      out->max_uV - out->min_uV);
}

static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV)
{
	struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
	struct vctrl_voltage_range *out = &vctrl->vrange.out;

	if (ctrl_uV < 0) {
		pr_err("vctrl: failed to get control voltage\n");
		return ctrl_uV;
	}

	if (ctrl_uV < ctrl->min_uV)
		return out->min_uV;

	if (ctrl_uV > ctrl->max_uV)
		return out->max_uV;

	return out->min_uV +
		DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) *
				      (out->max_uV - out->min_uV),
				      ctrl->max_uV - ctrl->min_uV);
}

static int vctrl_get_voltage(struct regulator_dev *rdev)
{
	struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
	int ctrl_uV = regulator_get_voltage_rdev(vctrl->ctrl_reg->rdev);

	return vctrl_calc_output_voltage(vctrl, ctrl_uV);
}

static int vctrl_set_voltage(struct regulator_dev *rdev,
			     int req_min_uV, int req_max_uV,
			     unsigned int *selector)
{
	struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
	struct regulator *ctrl_reg = vctrl->ctrl_reg;
	int orig_ctrl_uV = regulator_get_voltage_rdev(ctrl_reg->rdev);
	int uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV);
	int ret;

	if (req_min_uV >= uV || !vctrl->ovp_threshold)
		/* voltage rising or no OVP */
		return regulator_set_voltage_rdev(ctrl_reg->rdev,
			vctrl_calc_ctrl_voltage(vctrl, req_min_uV),
			vctrl_calc_ctrl_voltage(vctrl, req_max_uV),
			PM_SUSPEND_ON);

	while (uV > req_min_uV) {
		int max_drop_uV = (uV * vctrl->ovp_threshold) / 100;
		int next_uV;
		int next_ctrl_uV;
		int delay;

		/* Make sure no infinite loop even in crazy cases */
		if (max_drop_uV == 0)
			max_drop_uV = 1;

		next_uV = max_t(int, req_min_uV, uV - max_drop_uV);
		next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV);

		ret = regulator_set_voltage_rdev(ctrl_reg->rdev,
					    next_ctrl_uV,
					    next_ctrl_uV,
					    PM_SUSPEND_ON);
		if (ret)
			goto err;

		delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate);
		usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));

		uV = next_uV;
	}

	return 0;

err:
	/* Try to go back to original voltage */
	regulator_set_voltage_rdev(ctrl_reg->rdev, orig_ctrl_uV, orig_ctrl_uV,
				   PM_SUSPEND_ON);

	return ret;
}

static int vctrl_get_voltage_sel(struct regulator_dev *rdev)
{
	struct vctrl_data *vctrl = rdev_get_drvdata(rdev);

	return vctrl->sel;
}

static int vctrl_set_voltage_sel(struct regulator_dev *rdev,
				 unsigned int selector)
{
	struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
	struct regulator *ctrl_reg = vctrl->ctrl_reg;
	unsigned int orig_sel = vctrl->sel;
	int ret;

	if (selector >= rdev->desc->n_voltages)
		return -EINVAL;

	if (selector >= vctrl->sel || !vctrl->ovp_threshold) {
		/* voltage rising or no OVP */
		ret = regulator_set_voltage_rdev(ctrl_reg->rdev,
					    vctrl->vtable[selector].ctrl,
					    vctrl->vtable[selector].ctrl,
					    PM_SUSPEND_ON);
		if (!ret)
			vctrl->sel = selector;

		return ret;
	}

	while (vctrl->sel != selector) {
		unsigned int next_sel;
		int delay;

		if (selector >= vctrl->vtable[vctrl->sel].ovp_min_sel)
			next_sel = selector;
		else
			next_sel = vctrl->vtable[vctrl->sel].ovp_min_sel;

		ret = regulator_set_voltage_rdev(ctrl_reg->rdev,
					    vctrl->vtable[next_sel].ctrl,
					    vctrl->vtable[next_sel].ctrl,
					    PM_SUSPEND_ON);
		if (ret) {
			dev_err(&rdev->dev,
				"failed to set control voltage to %duV\n",
				vctrl->vtable[next_sel].ctrl);
			goto err;
		}
		vctrl->sel = next_sel;

		delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out -
				     vctrl->vtable[next_sel].out,
				     vctrl->min_slew_down_rate);
		usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
	}

	return 0;

err:
	if (vctrl->sel != orig_sel) {
		/* Try to go back to original voltage */
		if (!regulator_set_voltage_rdev(ctrl_reg->rdev,
					   vctrl->vtable[orig_sel].ctrl,
					   vctrl->vtable[orig_sel].ctrl,
					   PM_SUSPEND_ON))
			vctrl->sel = orig_sel;
		else
			dev_warn(&rdev->dev,
				 "failed to restore original voltage\n");
	}

	return ret;
}

static int vctrl_list_voltage(struct regulator_dev *rdev,
			      unsigned int selector)
{
	struct vctrl_data *vctrl = rdev_get_drvdata(rdev);

	if (selector >= rdev->desc->n_voltages)
		return -EINVAL;

	return vctrl->vtable[selector].out;
}

static int vctrl_parse_dt(struct platform_device *pdev,
			  struct vctrl_data *vctrl)
{
	int ret;
	struct device_node *np = pdev->dev.of_node;
	u32 pval;
	u32 vrange_ctrl[2];

	vctrl->ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl");
	if (IS_ERR(vctrl->ctrl_reg))
		return PTR_ERR(vctrl->ctrl_reg);

	ret = of_property_read_u32(np, "ovp-threshold-percent", &pval);
	if (!ret) {
		vctrl->ovp_threshold = pval;
		if (vctrl->ovp_threshold > 100) {
			dev_err(&pdev->dev,
				"ovp-threshold-percent (%u) > 100\n",
				vctrl->ovp_threshold);
			return -EINVAL;
		}
	}

	ret = of_property_read_u32(np, "min-slew-down-rate", &pval);
	if (!ret) {
		vctrl->min_slew_down_rate = pval;

		/* We use the value as int and as divider; sanity check */
		if (vctrl->min_slew_down_rate == 0) {
			dev_err(&pdev->dev,
				"min-slew-down-rate must not be 0\n");
			return -EINVAL;
		} else if (vctrl->min_slew_down_rate > INT_MAX) {
			dev_err(&pdev->dev, "min-slew-down-rate (%u) too big\n",
				vctrl->min_slew_down_rate);
			return -EINVAL;
		}
	}

	if (vctrl->ovp_threshold && !vctrl->min_slew_down_rate) {
		dev_err(&pdev->dev,
			"ovp-threshold-percent requires min-slew-down-rate\n");
		return -EINVAL;
	}

	ret = of_property_read_u32(np, "regulator-min-microvolt", &pval);
	if (ret) {
		dev_err(&pdev->dev,
			"failed to read regulator-min-microvolt: %d\n", ret);
		return ret;
	}
	vctrl->vrange.out.min_uV = pval;

	ret = of_property_read_u32(np, "regulator-max-microvolt", &pval);
	if (ret) {
		dev_err(&pdev->dev,
			"failed to read regulator-max-microvolt: %d\n", ret);
		return ret;
	}
	vctrl->vrange.out.max_uV = pval;

	ret = of_property_read_u32_array(np, "ctrl-voltage-range", vrange_ctrl,
					 2);
	if (ret) {
		dev_err(&pdev->dev, "failed to read ctrl-voltage-range: %d\n",
			ret);
		return ret;
	}

	if (vrange_ctrl[0] >= vrange_ctrl[1]) {
		dev_err(&pdev->dev, "ctrl-voltage-range is invalid: %d-%d\n",
			vrange_ctrl[0], vrange_ctrl[1]);
		return -EINVAL;
	}

	vctrl->vrange.ctrl.min_uV = vrange_ctrl[0];
	vctrl->vrange.ctrl.max_uV = vrange_ctrl[1];

	return 0;
}

static int vctrl_cmp_ctrl_uV(const void *a, const void *b)
{
	const struct vctrl_voltage_table *at = a;
	const struct vctrl_voltage_table *bt = b;

	return at->ctrl - bt->ctrl;
}

static int vctrl_init_vtable(struct platform_device *pdev)
{
	struct vctrl_data *vctrl = platform_get_drvdata(pdev);
	struct regulator_desc *rdesc = &vctrl->desc;
	struct regulator *ctrl_reg = vctrl->ctrl_reg;
	struct vctrl_voltage_range *vrange_ctrl = &vctrl->vrange.ctrl;
	int n_voltages;
	int ctrl_uV;
	int i, idx_vt;

	n_voltages = regulator_count_voltages(ctrl_reg);

	rdesc->n_voltages = n_voltages;

	/* determine number of steps within the range of the vctrl regulator */
	for (i = 0; i < n_voltages; i++) {
		ctrl_uV = regulator_list_voltage(ctrl_reg, i);

		if (ctrl_uV < vrange_ctrl->min_uV ||
		    ctrl_uV > vrange_ctrl->max_uV)
			rdesc->n_voltages--;
	}

	if (rdesc->n_voltages == 0) {
		dev_err(&pdev->dev, "invalid configuration\n");
		return -EINVAL;
	}

	vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages,
				     sizeof(struct vctrl_voltage_table),
				     GFP_KERNEL);
	if (!vctrl->vtable)
		return -ENOMEM;

	/* create mapping control <=> output voltage */
	for (i = 0, idx_vt = 0; i < n_voltages; i++) {
		ctrl_uV = regulator_list_voltage(ctrl_reg, i);

		if (ctrl_uV < vrange_ctrl->min_uV ||
		    ctrl_uV > vrange_ctrl->max_uV)
			continue;

		vctrl->vtable[idx_vt].ctrl = ctrl_uV;
		vctrl->vtable[idx_vt].out =
			vctrl_calc_output_voltage(vctrl, ctrl_uV);
		idx_vt++;
	}

	/* we rely on the table to be ordered by ascending voltage */
	sort(vctrl->vtable, rdesc->n_voltages,
	     sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV,
	     NULL);

	/* pre-calculate OVP-safe downward transitions */
	for (i = rdesc->n_voltages - 1; i > 0; i--) {
		int j;
		int ovp_min_uV = (vctrl->vtable[i].out *
				  (100 - vctrl->ovp_threshold)) / 100;

		for (j = 0; j < i; j++) {
			if (vctrl->vtable[j].out >= ovp_min_uV) {
				vctrl->vtable[i].ovp_min_sel = j;
				break;
			}
		}

		if (j == i) {
			dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n",
				vctrl->vtable[i].out);
			/* use next lowest voltage */
			vctrl->vtable[i].ovp_min_sel = i - 1;
		}
	}

	return 0;
}

static int vctrl_enable(struct regulator_dev *rdev)
{
	struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
	int ret = regulator_enable(vctrl->ctrl_reg);

	if (!ret)
		vctrl->enabled = true;

	return ret;
}

static int vctrl_disable(struct regulator_dev *rdev)
{
	struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
	int ret = regulator_disable(vctrl->ctrl_reg);

	if (!ret)
		vctrl->enabled = false;

	return ret;
}

static int vctrl_is_enabled(struct regulator_dev *rdev)
{
	struct vctrl_data *vctrl = rdev_get_drvdata(rdev);

	return vctrl->enabled;
}

static const struct regulator_ops vctrl_ops_cont = {
	.enable		  = vctrl_enable,
	.disable	  = vctrl_disable,
	.is_enabled	  = vctrl_is_enabled,
	.get_voltage	  = vctrl_get_voltage,
	.set_voltage	  = vctrl_set_voltage,
};

static const struct regulator_ops vctrl_ops_non_cont = {
	.enable		  = vctrl_enable,
	.disable	  = vctrl_disable,
	.is_enabled	  = vctrl_is_enabled,
	.set_voltage_sel = vctrl_set_voltage_sel,
	.get_voltage_sel = vctrl_get_voltage_sel,
	.list_voltage    = vctrl_list_voltage,
	.map_voltage     = regulator_map_voltage_iterate,
};

static int vctrl_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct vctrl_data *vctrl;
	const struct regulator_init_data *init_data;
	struct regulator_desc *rdesc;
	struct regulator_config cfg = { };
	struct vctrl_voltage_range *vrange_ctrl;
	int ctrl_uV;
	int ret;

	vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data),
			     GFP_KERNEL);
	if (!vctrl)
		return -ENOMEM;

	platform_set_drvdata(pdev, vctrl);

	ret = vctrl_parse_dt(pdev, vctrl);
	if (ret)
		return ret;

	vrange_ctrl = &vctrl->vrange.ctrl;

	rdesc = &vctrl->desc;
	rdesc->name = "vctrl";
	rdesc->type = REGULATOR_VOLTAGE;
	rdesc->owner = THIS_MODULE;

	if ((regulator_get_linear_step(vctrl->ctrl_reg) == 1) ||
	    (regulator_count_voltages(vctrl->ctrl_reg) == -EINVAL)) {
		rdesc->continuous_voltage_range = true;
		rdesc->ops = &vctrl_ops_cont;
	} else {
		rdesc->ops = &vctrl_ops_non_cont;
	}

	init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc);
	if (!init_data)
		return -ENOMEM;

	cfg.of_node = np;
	cfg.dev = &pdev->dev;
	cfg.driver_data = vctrl;
	cfg.init_data = init_data;

	if (!rdesc->continuous_voltage_range) {
		ret = vctrl_init_vtable(pdev);
		if (ret)
			return ret;

		ctrl_uV = regulator_get_voltage_rdev(vctrl->ctrl_reg->rdev);
		if (ctrl_uV < 0) {
			dev_err(&pdev->dev, "failed to get control voltage\n");
			return ctrl_uV;
		}

		/* determine current voltage selector from control voltage */
		if (ctrl_uV < vrange_ctrl->min_uV) {
			vctrl->sel = 0;
		} else if (ctrl_uV > vrange_ctrl->max_uV) {
			vctrl->sel = rdesc->n_voltages - 1;
		} else {
			int i;

			for (i = 0; i < rdesc->n_voltages; i++) {
				if (ctrl_uV == vctrl->vtable[i].ctrl) {
					vctrl->sel = i;
					break;
				}
			}
		}
	}

	vctrl->rdev = devm_regulator_register(&pdev->dev, rdesc, &cfg);
	if (IS_ERR(vctrl->rdev)) {
		ret = PTR_ERR(vctrl->rdev);
		dev_err(&pdev->dev, "failed to register regulator: %d\n", ret);
		return ret;
	}

	return 0;
}

static const struct of_device_id vctrl_of_match[] = {
	{ .compatible = "vctrl-regulator", },
	{},
};
MODULE_DEVICE_TABLE(of, vctrl_of_match);

static struct platform_driver vctrl_driver = {
	.probe		= vctrl_probe,
	.driver		= {
		.name		= "vctrl-regulator",
		.of_match_table = of_match_ptr(vctrl_of_match),
	},
};

module_platform_driver(vctrl_driver);

MODULE_DESCRIPTION("Voltage Controlled Regulator Driver");
MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
MODULE_LICENSE("GPL v2");