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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
4 *
5 * Authors:
6 * Maxim Kaurkin <maxim.kaurkin@baikalelectronics.ru>
7 * Serge Semin <Sergey.Semin@baikalelectronics.ru>
8 *
9 * Baikal-T1 Process, Voltage, Temperature sensor driver
10 */
11
12#include <linux/bitfield.h>
13#include <linux/bitops.h>
14#include <linux/clk.h>
15#include <linux/completion.h>
16#include <linux/delay.h>
17#include <linux/device.h>
18#include <linux/hwmon-sysfs.h>
19#include <linux/hwmon.h>
20#include <linux/interrupt.h>
21#include <linux/io.h>
22#include <linux/kernel.h>
23#include <linux/ktime.h>
24#include <linux/limits.h>
25#include <linux/module.h>
26#include <linux/mutex.h>
27#include <linux/of.h>
28#include <linux/platform_device.h>
29#include <linux/seqlock.h>
30#include <linux/sysfs.h>
31#include <linux/types.h>
32
33#include "bt1-pvt.h"
34
35/*
36 * For the sake of the code simplification we created the sensors info table
37 * with the sensor names, activation modes, threshold registers base address
38 * and the thresholds bit fields.
39 */
40static const struct pvt_sensor_info pvt_info[] = {
41 PVT_SENSOR_INFO(0, "CPU Core Temperature", hwmon_temp, TEMP, TTHRES),
42 PVT_SENSOR_INFO(0, "CPU Core Voltage", hwmon_in, VOLT, VTHRES),
43 PVT_SENSOR_INFO(1, "CPU Core Low-Vt", hwmon_in, LVT, LTHRES),
44 PVT_SENSOR_INFO(2, "CPU Core High-Vt", hwmon_in, HVT, HTHRES),
45 PVT_SENSOR_INFO(3, "CPU Core Standard-Vt", hwmon_in, SVT, STHRES),
46};
47
48/*
49 * The original translation formulae of the temperature (in degrees of Celsius)
50 * to PVT data and vice-versa are following:
51 * N = 1.8322e-8*(T^4) + 2.343e-5*(T^3) + 8.7018e-3*(T^2) + 3.9269*(T^1) +
52 * 1.7204e2,
53 * T = -1.6743e-11*(N^4) + 8.1542e-8*(N^3) + -1.8201e-4*(N^2) +
54 * 3.1020e-1*(N^1) - 4.838e1,
55 * where T = [-48.380, 147.438]C and N = [0, 1023].
56 * They must be accordingly altered to be suitable for the integer arithmetics.
57 * The technique is called 'factor redistribution', which just makes sure the
58 * multiplications and divisions are made so to have a result of the operations
59 * within the integer numbers limit. In addition we need to translate the
60 * formulae to accept millidegrees of Celsius. Here what they look like after
61 * the alterations:
62 * N = (18322e-20*(T^4) + 2343e-13*(T^3) + 87018e-9*(T^2) + 39269e-3*T +
63 * 17204e2) / 1e4,
64 * T = -16743e-12*(D^4) + 81542e-9*(D^3) - 182010e-6*(D^2) + 310200e-3*D -
65 * 48380,
66 * where T = [-48380, 147438] mC and N = [0, 1023].
67 */
68static const struct pvt_poly __maybe_unused poly_temp_to_N = {
69 .total_divider = 10000,
70 .terms = {
71 {4, 18322, 10000, 10000},
72 {3, 2343, 10000, 10},
73 {2, 87018, 10000, 10},
74 {1, 39269, 1000, 1},
75 {0, 1720400, 1, 1}
76 }
77};
78
79static const struct pvt_poly poly_N_to_temp = {
80 .total_divider = 1,
81 .terms = {
82 {4, -16743, 1000, 1},
83 {3, 81542, 1000, 1},
84 {2, -182010, 1000, 1},
85 {1, 310200, 1000, 1},
86 {0, -48380, 1, 1}
87 }
88};
89
90/*
91 * Similar alterations are performed for the voltage conversion equations.
92 * The original formulae are:
93 * N = 1.8658e3*V - 1.1572e3,
94 * V = (N + 1.1572e3) / 1.8658e3,
95 * where V = [0.620, 1.168] V and N = [0, 1023].
96 * After the optimization they looks as follows:
97 * N = (18658e-3*V - 11572) / 10,
98 * V = N * 10^5 / 18658 + 11572 * 10^4 / 18658.
99 */
100static const struct pvt_poly __maybe_unused poly_volt_to_N = {
101 .total_divider = 10,
102 .terms = {
103 {1, 18658, 1000, 1},
104 {0, -11572, 1, 1}
105 }
106};
107
108static const struct pvt_poly poly_N_to_volt = {
109 .total_divider = 10,
110 .terms = {
111 {1, 100000, 18658, 1},
112 {0, 115720000, 1, 18658}
113 }
114};
115
116/*
117 * Here is the polynomial calculation function, which performs the
118 * redistributed terms calculations. It's pretty straightforward. We walk
119 * over each degree term up to the free one, and perform the redistributed
120 * multiplication of the term coefficient, its divider (as for the rationale
121 * fraction representation), data power and the rational fraction divider
122 * leftover. Then all of this is collected in a total sum variable, which
123 * value is normalized by the total divider before being returned.
124 */
125static long pvt_calc_poly(const struct pvt_poly *poly, long data)
126{
127 const struct pvt_poly_term *term = poly->terms;
128 long tmp, ret = 0;
129 int deg;
130
131 do {
132 tmp = term->coef;
133 for (deg = 0; deg < term->deg; ++deg)
134 tmp = mult_frac(tmp, data, term->divider);
135 ret += tmp / term->divider_leftover;
136 } while ((term++)->deg);
137
138 return ret / poly->total_divider;
139}
140
141static inline u32 pvt_update(void __iomem *reg, u32 mask, u32 data)
142{
143 u32 old;
144
145 old = readl_relaxed(reg);
146 writel((old & ~mask) | (data & mask), reg);
147
148 return old & mask;
149}
150
151/*
152 * Baikal-T1 PVT mode can be updated only when the controller is disabled.
153 * So first we disable it, then set the new mode together with the controller
154 * getting back enabled. The same concerns the temperature trim and
155 * measurements timeout. If it is necessary the interface mutex is supposed
156 * to be locked at the time the operations are performed.
157 */
158static inline void pvt_set_mode(struct pvt_hwmon *pvt, u32 mode)
159{
160 u32 old;
161
162 mode = FIELD_PREP(PVT_CTRL_MODE_MASK, mode);
163
164 old = pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
165 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_MODE_MASK | PVT_CTRL_EN,
166 mode | old);
167}
168
169static inline u32 pvt_calc_trim(long temp)
170{
171 temp = clamp_val(temp, 0, PVT_TRIM_TEMP);
172
173 return DIV_ROUND_UP(temp, PVT_TRIM_STEP);
174}
175
176static inline void pvt_set_trim(struct pvt_hwmon *pvt, u32 trim)
177{
178 u32 old;
179
180 trim = FIELD_PREP(PVT_CTRL_TRIM_MASK, trim);
181
182 old = pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
183 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_TRIM_MASK | PVT_CTRL_EN,
184 trim | old);
185}
186
187static inline void pvt_set_tout(struct pvt_hwmon *pvt, u32 tout)
188{
189 u32 old;
190
191 old = pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
192 writel(tout, pvt->regs + PVT_TTIMEOUT);
193 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, old);
194}
195
196/*
197 * This driver can optionally provide the hwmon alarms for each sensor the PVT
198 * controller supports. The alarms functionality is made compile-time
199 * configurable due to the hardware interface implementation peculiarity
200 * described further in this comment. So in case if alarms are unnecessary in
201 * your system design it's recommended to have them disabled to prevent the PVT
202 * IRQs being periodically raised to get the data cache/alarms status up to
203 * date.
204 *
205 * Baikal-T1 PVT embedded controller is based on the Analog Bits PVT sensor,
206 * but is equipped with a dedicated control wrapper. It exposes the PVT
207 * sub-block registers space via the APB3 bus. In addition the wrapper provides
208 * a common interrupt vector of the sensors conversion completion events and
209 * threshold value alarms. Alas the wrapper interface hasn't been fully thought
210 * through. There is only one sensor can be activated at a time, for which the
211 * thresholds comparator is enabled right after the data conversion is
212 * completed. Due to this if alarms need to be implemented for all available
213 * sensors we can't just set the thresholds and enable the interrupts. We need
214 * to enable the sensors one after another and let the controller to detect
215 * the alarms by itself at each conversion. This also makes pointless to handle
216 * the alarms interrupts, since in occasion they happen synchronously with
217 * data conversion completion. The best driver design would be to have the
218 * completion interrupts enabled only and keep the converted value in the
219 * driver data cache. This solution is implemented if hwmon alarms are enabled
220 * in this driver. In case if the alarms are disabled, the conversion is
221 * performed on demand at the time a sensors input file is read.
222 */
223
224#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
225
226#define pvt_hard_isr NULL
227
228static irqreturn_t pvt_soft_isr(int irq, void *data)
229{
230 const struct pvt_sensor_info *info;
231 struct pvt_hwmon *pvt = data;
232 struct pvt_cache *cache;
233 u32 val, thres_sts, old;
234
235 /*
236 * DVALID bit will be cleared by reading the data. We need to save the
237 * status before the next conversion happens. Threshold events will be
238 * handled a bit later.
239 */
240 thres_sts = readl(pvt->regs + PVT_RAW_INTR_STAT);
241
242 /*
243 * Then lets recharge the PVT interface with the next sampling mode.
244 * Lock the interface mutex to serialize trim, timeouts and alarm
245 * thresholds settings.
246 */
247 cache = &pvt->cache[pvt->sensor];
248 info = &pvt_info[pvt->sensor];
249 pvt->sensor = (pvt->sensor == PVT_SENSOR_LAST) ?
250 PVT_SENSOR_FIRST : (pvt->sensor + 1);
251
252 /*
253 * For some reason we have to mask the interrupt before changing the
254 * mode, otherwise sometimes the temperature mode doesn't get
255 * activated even though the actual mode in the ctrl register
256 * corresponds to one. Then we read the data. By doing so we also
257 * recharge the data conversion. After this the mode corresponding
258 * to the next sensor in the row is set. Finally we enable the
259 * interrupts back.
260 */
261 mutex_lock(&pvt->iface_mtx);
262
263 old = pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID,
264 PVT_INTR_DVALID);
265
266 val = readl(pvt->regs + PVT_DATA);
267
268 pvt_set_mode(pvt, pvt_info[pvt->sensor].mode);
269
270 pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID, old);
271
272 mutex_unlock(&pvt->iface_mtx);
273
274 /*
275 * We can now update the data cache with data just retrieved from the
276 * sensor. Lock write-seqlock to make sure the reader has a coherent
277 * data.
278 */
279 write_seqlock(&cache->data_seqlock);
280
281 cache->data = FIELD_GET(PVT_DATA_DATA_MASK, val);
282
283 write_sequnlock(&cache->data_seqlock);
284
285 /*
286 * While PVT core is doing the next mode data conversion, we'll check
287 * whether the alarms were triggered for the current sensor. Note that
288 * according to the documentation only one threshold IRQ status can be
289 * set at a time, that's why if-else statement is utilized.
290 */
291 if ((thres_sts & info->thres_sts_lo) ^ cache->thres_sts_lo) {
292 WRITE_ONCE(cache->thres_sts_lo, thres_sts & info->thres_sts_lo);
293 hwmon_notify_event(pvt->hwmon, info->type, info->attr_min_alarm,
294 info->channel);
295 } else if ((thres_sts & info->thres_sts_hi) ^ cache->thres_sts_hi) {
296 WRITE_ONCE(cache->thres_sts_hi, thres_sts & info->thres_sts_hi);
297 hwmon_notify_event(pvt->hwmon, info->type, info->attr_max_alarm,
298 info->channel);
299 }
300
301 return IRQ_HANDLED;
302}
303
304static inline umode_t pvt_limit_is_visible(enum pvt_sensor_type type)
305{
306 return 0644;
307}
308
309static inline umode_t pvt_alarm_is_visible(enum pvt_sensor_type type)
310{
311 return 0444;
312}
313
314static int pvt_read_data(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
315 long *val)
316{
317 struct pvt_cache *cache = &pvt->cache[type];
318 unsigned int seq;
319 u32 data;
320
321 do {
322 seq = read_seqbegin(&cache->data_seqlock);
323 data = cache->data;
324 } while (read_seqretry(&cache->data_seqlock, seq));
325
326 if (type == PVT_TEMP)
327 *val = pvt_calc_poly(&poly_N_to_temp, data);
328 else
329 *val = pvt_calc_poly(&poly_N_to_volt, data);
330
331 return 0;
332}
333
334static int pvt_read_limit(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
335 bool is_low, long *val)
336{
337 u32 data;
338
339 /* No need in serialization, since it is just read from MMIO. */
340 data = readl(pvt->regs + pvt_info[type].thres_base);
341
342 if (is_low)
343 data = FIELD_GET(PVT_THRES_LO_MASK, data);
344 else
345 data = FIELD_GET(PVT_THRES_HI_MASK, data);
346
347 if (type == PVT_TEMP)
348 *val = pvt_calc_poly(&poly_N_to_temp, data);
349 else
350 *val = pvt_calc_poly(&poly_N_to_volt, data);
351
352 return 0;
353}
354
355static int pvt_write_limit(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
356 bool is_low, long val)
357{
358 u32 data, limit, mask;
359 int ret;
360
361 if (type == PVT_TEMP) {
362 val = clamp(val, PVT_TEMP_MIN, PVT_TEMP_MAX);
363 data = pvt_calc_poly(&poly_temp_to_N, val);
364 } else {
365 val = clamp(val, PVT_VOLT_MIN, PVT_VOLT_MAX);
366 data = pvt_calc_poly(&poly_volt_to_N, val);
367 }
368
369 /* Serialize limit update, since a part of the register is changed. */
370 ret = mutex_lock_interruptible(&pvt->iface_mtx);
371 if (ret)
372 return ret;
373
374 /* Make sure the upper and lower ranges don't intersect. */
375 limit = readl(pvt->regs + pvt_info[type].thres_base);
376 if (is_low) {
377 limit = FIELD_GET(PVT_THRES_HI_MASK, limit);
378 data = clamp_val(data, PVT_DATA_MIN, limit);
379 data = FIELD_PREP(PVT_THRES_LO_MASK, data);
380 mask = PVT_THRES_LO_MASK;
381 } else {
382 limit = FIELD_GET(PVT_THRES_LO_MASK, limit);
383 data = clamp_val(data, limit, PVT_DATA_MAX);
384 data = FIELD_PREP(PVT_THRES_HI_MASK, data);
385 mask = PVT_THRES_HI_MASK;
386 }
387
388 pvt_update(pvt->regs + pvt_info[type].thres_base, mask, data);
389
390 mutex_unlock(&pvt->iface_mtx);
391
392 return 0;
393}
394
395static int pvt_read_alarm(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
396 bool is_low, long *val)
397{
398 if (is_low)
399 *val = !!READ_ONCE(pvt->cache[type].thres_sts_lo);
400 else
401 *val = !!READ_ONCE(pvt->cache[type].thres_sts_hi);
402
403 return 0;
404}
405
406static const struct hwmon_channel_info *pvt_channel_info[] = {
407 HWMON_CHANNEL_INFO(chip,
408 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
409 HWMON_CHANNEL_INFO(temp,
410 HWMON_T_INPUT | HWMON_T_TYPE | HWMON_T_LABEL |
411 HWMON_T_MIN | HWMON_T_MIN_ALARM |
412 HWMON_T_MAX | HWMON_T_MAX_ALARM |
413 HWMON_T_OFFSET),
414 HWMON_CHANNEL_INFO(in,
415 HWMON_I_INPUT | HWMON_I_LABEL |
416 HWMON_I_MIN | HWMON_I_MIN_ALARM |
417 HWMON_I_MAX | HWMON_I_MAX_ALARM,
418 HWMON_I_INPUT | HWMON_I_LABEL |
419 HWMON_I_MIN | HWMON_I_MIN_ALARM |
420 HWMON_I_MAX | HWMON_I_MAX_ALARM,
421 HWMON_I_INPUT | HWMON_I_LABEL |
422 HWMON_I_MIN | HWMON_I_MIN_ALARM |
423 HWMON_I_MAX | HWMON_I_MAX_ALARM,
424 HWMON_I_INPUT | HWMON_I_LABEL |
425 HWMON_I_MIN | HWMON_I_MIN_ALARM |
426 HWMON_I_MAX | HWMON_I_MAX_ALARM),
427 NULL
428};
429
430#else /* !CONFIG_SENSORS_BT1_PVT_ALARMS */
431
432static irqreturn_t pvt_hard_isr(int irq, void *data)
433{
434 struct pvt_hwmon *pvt = data;
435 struct pvt_cache *cache;
436 u32 val;
437
438 /*
439 * Mask the DVALID interrupt so after exiting from the handler a
440 * repeated conversion wouldn't happen.
441 */
442 pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID,
443 PVT_INTR_DVALID);
444
445 /*
446 * Nothing special for alarm-less driver. Just read the data, update
447 * the cache and notify a waiter of this event.
448 */
449 val = readl(pvt->regs + PVT_DATA);
450 if (!(val & PVT_DATA_VALID)) {
451 dev_err(pvt->dev, "Got IRQ when data isn't valid\n");
452 return IRQ_HANDLED;
453 }
454
455 cache = &pvt->cache[pvt->sensor];
456
457 WRITE_ONCE(cache->data, FIELD_GET(PVT_DATA_DATA_MASK, val));
458
459 complete(&cache->conversion);
460
461 return IRQ_HANDLED;
462}
463
464#define pvt_soft_isr NULL
465
466static inline umode_t pvt_limit_is_visible(enum pvt_sensor_type type)
467{
468 return 0;
469}
470
471static inline umode_t pvt_alarm_is_visible(enum pvt_sensor_type type)
472{
473 return 0;
474}
475
476static int pvt_read_data(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
477 long *val)
478{
479 struct pvt_cache *cache = &pvt->cache[type];
480 unsigned long timeout;
481 u32 data;
482 int ret;
483
484 /*
485 * Lock PVT conversion interface until data cache is updated. The
486 * data read procedure is following: set the requested PVT sensor
487 * mode, enable IRQ and conversion, wait until conversion is finished,
488 * then disable conversion and IRQ, and read the cached data.
489 */
490 ret = mutex_lock_interruptible(&pvt->iface_mtx);
491 if (ret)
492 return ret;
493
494 pvt->sensor = type;
495 pvt_set_mode(pvt, pvt_info[type].mode);
496
497 /*
498 * Unmask the DVALID interrupt and enable the sensors conversions.
499 * Do the reverse procedure when conversion is done.
500 */
501 pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID, 0);
502 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, PVT_CTRL_EN);
503
504 /*
505 * Wait with timeout since in case if the sensor is suddenly powered
506 * down the request won't be completed and the caller will hang up on
507 * this procedure until the power is back up again. Multiply the
508 * timeout by the factor of two to prevent a false timeout.
509 */
510 timeout = 2 * usecs_to_jiffies(ktime_to_us(pvt->timeout));
511 ret = wait_for_completion_timeout(&cache->conversion, timeout);
512
513 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
514 pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID,
515 PVT_INTR_DVALID);
516
517 data = READ_ONCE(cache->data);
518
519 mutex_unlock(&pvt->iface_mtx);
520
521 if (!ret)
522 return -ETIMEDOUT;
523
524 if (type == PVT_TEMP)
525 *val = pvt_calc_poly(&poly_N_to_temp, data);
526 else
527 *val = pvt_calc_poly(&poly_N_to_volt, data);
528
529 return 0;
530}
531
532static int pvt_read_limit(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
533 bool is_low, long *val)
534{
535 return -EOPNOTSUPP;
536}
537
538static int pvt_write_limit(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
539 bool is_low, long val)
540{
541 return -EOPNOTSUPP;
542}
543
544static int pvt_read_alarm(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
545 bool is_low, long *val)
546{
547 return -EOPNOTSUPP;
548}
549
550static const struct hwmon_channel_info *pvt_channel_info[] = {
551 HWMON_CHANNEL_INFO(chip,
552 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
553 HWMON_CHANNEL_INFO(temp,
554 HWMON_T_INPUT | HWMON_T_TYPE | HWMON_T_LABEL |
555 HWMON_T_OFFSET),
556 HWMON_CHANNEL_INFO(in,
557 HWMON_I_INPUT | HWMON_I_LABEL,
558 HWMON_I_INPUT | HWMON_I_LABEL,
559 HWMON_I_INPUT | HWMON_I_LABEL,
560 HWMON_I_INPUT | HWMON_I_LABEL),
561 NULL
562};
563
564#endif /* !CONFIG_SENSORS_BT1_PVT_ALARMS */
565
566static inline bool pvt_hwmon_channel_is_valid(enum hwmon_sensor_types type,
567 int ch)
568{
569 switch (type) {
570 case hwmon_temp:
571 if (ch < 0 || ch >= PVT_TEMP_CHS)
572 return false;
573 break;
574 case hwmon_in:
575 if (ch < 0 || ch >= PVT_VOLT_CHS)
576 return false;
577 break;
578 default:
579 break;
580 }
581
582 /* The rest of the types are independent from the channel number. */
583 return true;
584}
585
586static umode_t pvt_hwmon_is_visible(const void *data,
587 enum hwmon_sensor_types type,
588 u32 attr, int ch)
589{
590 if (!pvt_hwmon_channel_is_valid(type, ch))
591 return 0;
592
593 switch (type) {
594 case hwmon_chip:
595 switch (attr) {
596 case hwmon_chip_update_interval:
597 return 0644;
598 }
599 break;
600 case hwmon_temp:
601 switch (attr) {
602 case hwmon_temp_input:
603 case hwmon_temp_type:
604 case hwmon_temp_label:
605 return 0444;
606 case hwmon_temp_min:
607 case hwmon_temp_max:
608 return pvt_limit_is_visible(ch);
609 case hwmon_temp_min_alarm:
610 case hwmon_temp_max_alarm:
611 return pvt_alarm_is_visible(ch);
612 case hwmon_temp_offset:
613 return 0644;
614 }
615 break;
616 case hwmon_in:
617 switch (attr) {
618 case hwmon_in_input:
619 case hwmon_in_label:
620 return 0444;
621 case hwmon_in_min:
622 case hwmon_in_max:
623 return pvt_limit_is_visible(PVT_VOLT + ch);
624 case hwmon_in_min_alarm:
625 case hwmon_in_max_alarm:
626 return pvt_alarm_is_visible(PVT_VOLT + ch);
627 }
628 break;
629 default:
630 break;
631 }
632
633 return 0;
634}
635
636static int pvt_read_trim(struct pvt_hwmon *pvt, long *val)
637{
638 u32 data;
639
640 data = readl(pvt->regs + PVT_CTRL);
641 *val = FIELD_GET(PVT_CTRL_TRIM_MASK, data) * PVT_TRIM_STEP;
642
643 return 0;
644}
645
646static int pvt_write_trim(struct pvt_hwmon *pvt, long val)
647{
648 u32 trim;
649 int ret;
650
651 /*
652 * Serialize trim update, since a part of the register is changed and
653 * the controller is supposed to be disabled during this operation.
654 */
655 ret = mutex_lock_interruptible(&pvt->iface_mtx);
656 if (ret)
657 return ret;
658
659 trim = pvt_calc_trim(val);
660 pvt_set_trim(pvt, trim);
661
662 mutex_unlock(&pvt->iface_mtx);
663
664 return 0;
665}
666
667static int pvt_read_timeout(struct pvt_hwmon *pvt, long *val)
668{
669 int ret;
670
671 ret = mutex_lock_interruptible(&pvt->iface_mtx);
672 if (ret)
673 return ret;
674
675 /* Return the result in msec as hwmon sysfs interface requires. */
676 *val = ktime_to_ms(pvt->timeout);
677
678 mutex_unlock(&pvt->iface_mtx);
679
680 return 0;
681}
682
683static int pvt_write_timeout(struct pvt_hwmon *pvt, long val)
684{
685 unsigned long rate;
686 ktime_t kt, cache;
687 u32 data;
688 int ret;
689
690 rate = clk_get_rate(pvt->clks[PVT_CLOCK_REF].clk);
691 if (!rate)
692 return -ENODEV;
693
694 /*
695 * If alarms are enabled, the requested timeout must be divided
696 * between all available sensors to have the requested delay
697 * applicable to each individual sensor.
698 */
699 cache = kt = ms_to_ktime(val);
700#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
701 kt = ktime_divns(kt, PVT_SENSORS_NUM);
702#endif
703
704 /*
705 * Subtract a constant lag, which always persists due to the limited
706 * PVT sampling rate. Make sure the timeout is not negative.
707 */
708 kt = ktime_sub_ns(kt, PVT_TOUT_MIN);
709 if (ktime_to_ns(kt) < 0)
710 kt = ktime_set(0, 0);
711
712 /*
713 * Finally recalculate the timeout in terms of the reference clock
714 * period.
715 */
716 data = ktime_divns(kt * rate, NSEC_PER_SEC);
717
718 /*
719 * Update the measurements delay, but lock the interface first, since
720 * we have to disable PVT in order to have the new delay actually
721 * updated.
722 */
723 ret = mutex_lock_interruptible(&pvt->iface_mtx);
724 if (ret)
725 return ret;
726
727 pvt_set_tout(pvt, data);
728 pvt->timeout = cache;
729
730 mutex_unlock(&pvt->iface_mtx);
731
732 return 0;
733}
734
735static int pvt_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
736 u32 attr, int ch, long *val)
737{
738 struct pvt_hwmon *pvt = dev_get_drvdata(dev);
739
740 if (!pvt_hwmon_channel_is_valid(type, ch))
741 return -EINVAL;
742
743 switch (type) {
744 case hwmon_chip:
745 switch (attr) {
746 case hwmon_chip_update_interval:
747 return pvt_read_timeout(pvt, val);
748 }
749 break;
750 case hwmon_temp:
751 switch (attr) {
752 case hwmon_temp_input:
753 return pvt_read_data(pvt, ch, val);
754 case hwmon_temp_type:
755 *val = 1;
756 return 0;
757 case hwmon_temp_min:
758 return pvt_read_limit(pvt, ch, true, val);
759 case hwmon_temp_max:
760 return pvt_read_limit(pvt, ch, false, val);
761 case hwmon_temp_min_alarm:
762 return pvt_read_alarm(pvt, ch, true, val);
763 case hwmon_temp_max_alarm:
764 return pvt_read_alarm(pvt, ch, false, val);
765 case hwmon_temp_offset:
766 return pvt_read_trim(pvt, val);
767 }
768 break;
769 case hwmon_in:
770 switch (attr) {
771 case hwmon_in_input:
772 return pvt_read_data(pvt, PVT_VOLT + ch, val);
773 case hwmon_in_min:
774 return pvt_read_limit(pvt, PVT_VOLT + ch, true, val);
775 case hwmon_in_max:
776 return pvt_read_limit(pvt, PVT_VOLT + ch, false, val);
777 case hwmon_in_min_alarm:
778 return pvt_read_alarm(pvt, PVT_VOLT + ch, true, val);
779 case hwmon_in_max_alarm:
780 return pvt_read_alarm(pvt, PVT_VOLT + ch, false, val);
781 }
782 break;
783 default:
784 break;
785 }
786
787 return -EOPNOTSUPP;
788}
789
790static int pvt_hwmon_read_string(struct device *dev,
791 enum hwmon_sensor_types type,
792 u32 attr, int ch, const char **str)
793{
794 if (!pvt_hwmon_channel_is_valid(type, ch))
795 return -EINVAL;
796
797 switch (type) {
798 case hwmon_temp:
799 switch (attr) {
800 case hwmon_temp_label:
801 *str = pvt_info[ch].label;
802 return 0;
803 }
804 break;
805 case hwmon_in:
806 switch (attr) {
807 case hwmon_in_label:
808 *str = pvt_info[PVT_VOLT + ch].label;
809 return 0;
810 }
811 break;
812 default:
813 break;
814 }
815
816 return -EOPNOTSUPP;
817}
818
819static int pvt_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
820 u32 attr, int ch, long val)
821{
822 struct pvt_hwmon *pvt = dev_get_drvdata(dev);
823
824 if (!pvt_hwmon_channel_is_valid(type, ch))
825 return -EINVAL;
826
827 switch (type) {
828 case hwmon_chip:
829 switch (attr) {
830 case hwmon_chip_update_interval:
831 return pvt_write_timeout(pvt, val);
832 }
833 break;
834 case hwmon_temp:
835 switch (attr) {
836 case hwmon_temp_min:
837 return pvt_write_limit(pvt, ch, true, val);
838 case hwmon_temp_max:
839 return pvt_write_limit(pvt, ch, false, val);
840 case hwmon_temp_offset:
841 return pvt_write_trim(pvt, val);
842 }
843 break;
844 case hwmon_in:
845 switch (attr) {
846 case hwmon_in_min:
847 return pvt_write_limit(pvt, PVT_VOLT + ch, true, val);
848 case hwmon_in_max:
849 return pvt_write_limit(pvt, PVT_VOLT + ch, false, val);
850 }
851 break;
852 default:
853 break;
854 }
855
856 return -EOPNOTSUPP;
857}
858
859static const struct hwmon_ops pvt_hwmon_ops = {
860 .is_visible = pvt_hwmon_is_visible,
861 .read = pvt_hwmon_read,
862 .read_string = pvt_hwmon_read_string,
863 .write = pvt_hwmon_write
864};
865
866static const struct hwmon_chip_info pvt_hwmon_info = {
867 .ops = &pvt_hwmon_ops,
868 .info = pvt_channel_info
869};
870
871static void pvt_clear_data(void *data)
872{
873 struct pvt_hwmon *pvt = data;
874#if !defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
875 int idx;
876
877 for (idx = 0; idx < PVT_SENSORS_NUM; ++idx)
878 complete_all(&pvt->cache[idx].conversion);
879#endif
880
881 mutex_destroy(&pvt->iface_mtx);
882}
883
884static struct pvt_hwmon *pvt_create_data(struct platform_device *pdev)
885{
886 struct device *dev = &pdev->dev;
887 struct pvt_hwmon *pvt;
888 int ret, idx;
889
890 pvt = devm_kzalloc(dev, sizeof(*pvt), GFP_KERNEL);
891 if (!pvt)
892 return ERR_PTR(-ENOMEM);
893
894 ret = devm_add_action(dev, pvt_clear_data, pvt);
895 if (ret) {
896 dev_err(dev, "Can't add PVT data clear action\n");
897 return ERR_PTR(ret);
898 }
899
900 pvt->dev = dev;
901 pvt->sensor = PVT_SENSOR_FIRST;
902 mutex_init(&pvt->iface_mtx);
903
904#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
905 for (idx = 0; idx < PVT_SENSORS_NUM; ++idx)
906 seqlock_init(&pvt->cache[idx].data_seqlock);
907#else
908 for (idx = 0; idx < PVT_SENSORS_NUM; ++idx)
909 init_completion(&pvt->cache[idx].conversion);
910#endif
911
912 return pvt;
913}
914
915static int pvt_request_regs(struct pvt_hwmon *pvt)
916{
917 struct platform_device *pdev = to_platform_device(pvt->dev);
918 struct resource *res;
919
920 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
921 if (!res) {
922 dev_err(pvt->dev, "Couldn't find PVT memresource\n");
923 return -EINVAL;
924 }
925
926 pvt->regs = devm_ioremap_resource(pvt->dev, res);
927 if (IS_ERR(pvt->regs))
928 return PTR_ERR(pvt->regs);
929
930 return 0;
931}
932
933static void pvt_disable_clks(void *data)
934{
935 struct pvt_hwmon *pvt = data;
936
937 clk_bulk_disable_unprepare(PVT_CLOCK_NUM, pvt->clks);
938}
939
940static int pvt_request_clks(struct pvt_hwmon *pvt)
941{
942 int ret;
943
944 pvt->clks[PVT_CLOCK_APB].id = "pclk";
945 pvt->clks[PVT_CLOCK_REF].id = "ref";
946
947 ret = devm_clk_bulk_get(pvt->dev, PVT_CLOCK_NUM, pvt->clks);
948 if (ret) {
949 dev_err(pvt->dev, "Couldn't get PVT clocks descriptors\n");
950 return ret;
951 }
952
953 ret = clk_bulk_prepare_enable(PVT_CLOCK_NUM, pvt->clks);
954 if (ret) {
955 dev_err(pvt->dev, "Couldn't enable the PVT clocks\n");
956 return ret;
957 }
958
959 ret = devm_add_action_or_reset(pvt->dev, pvt_disable_clks, pvt);
960 if (ret) {
961 dev_err(pvt->dev, "Can't add PVT clocks disable action\n");
962 return ret;
963 }
964
965 return 0;
966}
967
968static int pvt_check_pwr(struct pvt_hwmon *pvt)
969{
970 unsigned long tout;
971 int ret = 0;
972 u32 data;
973
974 /*
975 * Test out the sensor conversion functionality. If it is not done on
976 * time then the domain must have been unpowered and we won't be able
977 * to use the device later in this driver.
978 * Note If the power source is lost during the normal driver work the
979 * data read procedure will either return -ETIMEDOUT (for the
980 * alarm-less driver configuration) or just stop the repeated
981 * conversion. In the later case alas we won't be able to detect the
982 * problem.
983 */
984 pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_ALL, PVT_INTR_ALL);
985 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, PVT_CTRL_EN);
986 pvt_set_tout(pvt, 0);
987 readl(pvt->regs + PVT_DATA);
988
989 tout = PVT_TOUT_MIN / NSEC_PER_USEC;
990 usleep_range(tout, 2 * tout);
991
992 data = readl(pvt->regs + PVT_DATA);
993 if (!(data & PVT_DATA_VALID)) {
994 ret = -ENODEV;
995 dev_err(pvt->dev, "Sensor is powered down\n");
996 }
997
998 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
999
1000 return ret;
1001}
1002
1003static int pvt_init_iface(struct pvt_hwmon *pvt)
1004{
1005 unsigned long rate;
1006 u32 trim, temp;
1007
1008 rate = clk_get_rate(pvt->clks[PVT_CLOCK_REF].clk);
1009 if (!rate) {
1010 dev_err(pvt->dev, "Invalid reference clock rate\n");
1011 return -ENODEV;
1012 }
1013
1014 /*
1015 * Make sure all interrupts and controller are disabled so not to
1016 * accidentally have ISR executed before the driver data is fully
1017 * initialized. Clear the IRQ status as well.
1018 */
1019 pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_ALL, PVT_INTR_ALL);
1020 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
1021 readl(pvt->regs + PVT_CLR_INTR);
1022 readl(pvt->regs + PVT_DATA);
1023
1024 /* Setup default sensor mode, timeout and temperature trim. */
1025 pvt_set_mode(pvt, pvt_info[pvt->sensor].mode);
1026 pvt_set_tout(pvt, PVT_TOUT_DEF);
1027
1028 /*
1029 * Preserve the current ref-clock based delay (Ttotal) between the
1030 * sensors data samples in the driver data so not to recalculate it
1031 * each time on the data requests and timeout reads. It consists of the
1032 * delay introduced by the internal ref-clock timer (N / Fclk) and the
1033 * constant timeout caused by each conversion latency (Tmin):
1034 * Ttotal = N / Fclk + Tmin
1035 * If alarms are enabled the sensors are polled one after another and
1036 * in order to get the next measurement of a particular sensor the
1037 * caller will have to wait for at most until all the others are
1038 * polled. In that case the formulae will look a bit different:
1039 * Ttotal = 5 * (N / Fclk + Tmin)
1040 */
1041#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
1042 pvt->timeout = ktime_set(PVT_SENSORS_NUM * PVT_TOUT_DEF, 0);
1043 pvt->timeout = ktime_divns(pvt->timeout, rate);
1044 pvt->timeout = ktime_add_ns(pvt->timeout, PVT_SENSORS_NUM * PVT_TOUT_MIN);
1045#else
1046 pvt->timeout = ktime_set(PVT_TOUT_DEF, 0);
1047 pvt->timeout = ktime_divns(pvt->timeout, rate);
1048 pvt->timeout = ktime_add_ns(pvt->timeout, PVT_TOUT_MIN);
1049#endif
1050
1051 trim = PVT_TRIM_DEF;
1052 if (!of_property_read_u32(pvt->dev->of_node,
1053 "baikal,pvt-temp-offset-millicelsius", &temp))
1054 trim = pvt_calc_trim(temp);
1055
1056 pvt_set_trim(pvt, trim);
1057
1058 return 0;
1059}
1060
1061static int pvt_request_irq(struct pvt_hwmon *pvt)
1062{
1063 struct platform_device *pdev = to_platform_device(pvt->dev);
1064 int ret;
1065
1066 pvt->irq = platform_get_irq(pdev, 0);
1067 if (pvt->irq < 0)
1068 return pvt->irq;
1069
1070 ret = devm_request_threaded_irq(pvt->dev, pvt->irq,
1071 pvt_hard_isr, pvt_soft_isr,
1072#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
1073 IRQF_SHARED | IRQF_TRIGGER_HIGH |
1074 IRQF_ONESHOT,
1075#else
1076 IRQF_SHARED | IRQF_TRIGGER_HIGH,
1077#endif
1078 "pvt", pvt);
1079 if (ret) {
1080 dev_err(pvt->dev, "Couldn't request PVT IRQ\n");
1081 return ret;
1082 }
1083
1084 return 0;
1085}
1086
1087static int pvt_create_hwmon(struct pvt_hwmon *pvt)
1088{
1089 pvt->hwmon = devm_hwmon_device_register_with_info(pvt->dev, "pvt", pvt,
1090 &pvt_hwmon_info, NULL);
1091 if (IS_ERR(pvt->hwmon)) {
1092 dev_err(pvt->dev, "Couldn't create hwmon device\n");
1093 return PTR_ERR(pvt->hwmon);
1094 }
1095
1096 return 0;
1097}
1098
1099#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
1100
1101static void pvt_disable_iface(void *data)
1102{
1103 struct pvt_hwmon *pvt = data;
1104
1105 mutex_lock(&pvt->iface_mtx);
1106 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
1107 pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID,
1108 PVT_INTR_DVALID);
1109 mutex_unlock(&pvt->iface_mtx);
1110}
1111
1112static int pvt_enable_iface(struct pvt_hwmon *pvt)
1113{
1114 int ret;
1115
1116 ret = devm_add_action(pvt->dev, pvt_disable_iface, pvt);
1117 if (ret) {
1118 dev_err(pvt->dev, "Can't add PVT disable interface action\n");
1119 return ret;
1120 }
1121
1122 /*
1123 * Enable sensors data conversion and IRQ. We need to lock the
1124 * interface mutex since hwmon has just been created and the
1125 * corresponding sysfs files are accessible from user-space,
1126 * which theoretically may cause races.
1127 */
1128 mutex_lock(&pvt->iface_mtx);
1129 pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID, 0);
1130 pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, PVT_CTRL_EN);
1131 mutex_unlock(&pvt->iface_mtx);
1132
1133 return 0;
1134}
1135
1136#else /* !CONFIG_SENSORS_BT1_PVT_ALARMS */
1137
1138static int pvt_enable_iface(struct pvt_hwmon *pvt)
1139{
1140 return 0;
1141}
1142
1143#endif /* !CONFIG_SENSORS_BT1_PVT_ALARMS */
1144
1145static int pvt_probe(struct platform_device *pdev)
1146{
1147 struct pvt_hwmon *pvt;
1148 int ret;
1149
1150 pvt = pvt_create_data(pdev);
1151 if (IS_ERR(pvt))
1152 return PTR_ERR(pvt);
1153
1154 ret = pvt_request_regs(pvt);
1155 if (ret)
1156 return ret;
1157
1158 ret = pvt_request_clks(pvt);
1159 if (ret)
1160 return ret;
1161
1162 ret = pvt_check_pwr(pvt);
1163 if (ret)
1164 return ret;
1165
1166 ret = pvt_init_iface(pvt);
1167 if (ret)
1168 return ret;
1169
1170 ret = pvt_request_irq(pvt);
1171 if (ret)
1172 return ret;
1173
1174 ret = pvt_create_hwmon(pvt);
1175 if (ret)
1176 return ret;
1177
1178 ret = pvt_enable_iface(pvt);
1179 if (ret)
1180 return ret;
1181
1182 return 0;
1183}
1184
1185static const struct of_device_id pvt_of_match[] = {
1186 { .compatible = "baikal,bt1-pvt" },
1187 { }
1188};
1189MODULE_DEVICE_TABLE(of, pvt_of_match);
1190
1191static struct platform_driver pvt_driver = {
1192 .probe = pvt_probe,
1193 .driver = {
1194 .name = "bt1-pvt",
1195 .of_match_table = pvt_of_match
1196 }
1197};
1198module_platform_driver(pvt_driver);
1199
1200MODULE_AUTHOR("Maxim Kaurkin <maxim.kaurkin@baikalelectronics.ru>");
1201MODULE_DESCRIPTION("Baikal-T1 PVT driver");
1202MODULE_LICENSE("GPL v2");