xref: /linux/drivers/counter/104-quad-8.c (revision 9e56ff53b4115875667760445b028357848b4748)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Counter driver for the ACCES 104-QUAD-8
4  * Copyright (C) 2016 William Breathitt Gray
5  *
6  * This driver supports the ACCES 104-QUAD-8 and ACCES 104-QUAD-4.
7  */
8 #include <linux/bitfield.h>
9 #include <linux/bits.h>
10 #include <linux/counter.h>
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/io.h>
14 #include <linux/ioport.h>
15 #include <linux/interrupt.h>
16 #include <linux/isa.h>
17 #include <linux/kernel.h>
18 #include <linux/list.h>
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/regmap.h>
22 #include <linux/spinlock.h>
23 #include <linux/types.h>
24 
25 #include <asm/unaligned.h>
26 
27 #define QUAD8_EXTENT 32
28 
29 static unsigned int base[max_num_isa_dev(QUAD8_EXTENT)];
30 static unsigned int num_quad8;
31 module_param_hw_array(base, uint, ioport, &num_quad8, 0);
32 MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
33 
34 static unsigned int irq[max_num_isa_dev(QUAD8_EXTENT)];
35 static unsigned int num_irq;
36 module_param_hw_array(irq, uint, irq, &num_irq, 0);
37 MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
38 
39 #define QUAD8_NUM_COUNTERS 8
40 
41 #define QUAD8_DATA(_channel) ((_channel) * 2)
42 #define QUAD8_CONTROL(_channel) (QUAD8_DATA(_channel) + 1)
43 #define QUAD8_INTERRUPT_STATUS 0x10
44 #define QUAD8_CHANNEL_OPERATION 0x11
45 #define QUAD8_INDEX_INTERRUPT 0x12
46 #define QUAD8_INDEX_INPUT_LEVELS 0x16
47 #define QUAD8_CABLE_STATUS 0x17
48 
49 /**
50  * struct quad8 - device private data structure
51  * @lock:		lock to prevent clobbering device states during R/W ops
52  * @cmr:		array of Counter Mode Register states
53  * @ior:		array of Input / Output Control Register states
54  * @idr:		array of Index Control Register states
55  * @fck_prescaler:	array of filter clock prescaler configurations
56  * @preset:		array of preset values
57  * @cable_fault_enable:	differential encoder cable status enable configurations
58  * @map:		regmap for the device
59  */
60 struct quad8 {
61 	spinlock_t lock;
62 	u8 cmr[QUAD8_NUM_COUNTERS];
63 	u8 ior[QUAD8_NUM_COUNTERS];
64 	u8 idr[QUAD8_NUM_COUNTERS];
65 	unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
66 	unsigned int preset[QUAD8_NUM_COUNTERS];
67 	unsigned int cable_fault_enable;
68 	struct regmap *map;
69 };
70 
71 static const struct regmap_range quad8_wr_ranges[] = {
72 	regmap_reg_range(0x0, 0xF), regmap_reg_range(0x11, 0x12), regmap_reg_range(0x17, 0x17),
73 };
74 static const struct regmap_range quad8_rd_ranges[] = {
75 	regmap_reg_range(0x0, 0x12), regmap_reg_range(0x16, 0x18),
76 };
77 static const struct regmap_access_table quad8_wr_table = {
78 	.yes_ranges = quad8_wr_ranges,
79 	.n_yes_ranges = ARRAY_SIZE(quad8_wr_ranges),
80 };
81 static const struct regmap_access_table quad8_rd_table = {
82 	.yes_ranges = quad8_rd_ranges,
83 	.n_yes_ranges = ARRAY_SIZE(quad8_rd_ranges),
84 };
85 static const struct regmap_config quad8_regmap_config = {
86 	.reg_bits = 8,
87 	.reg_stride = 1,
88 	.val_bits = 8,
89 	.io_port = true,
90 	.wr_table = &quad8_wr_table,
91 	.rd_table = &quad8_rd_table,
92 };
93 
94 /* Error flag */
95 #define FLAG_E BIT(4)
96 /* Up/Down flag */
97 #define FLAG_UD BIT(5)
98 /* Counting up */
99 #define UP 0x1
100 
101 #define REGISTER_SELECTION GENMASK(6, 5)
102 
103 /* Reset and Load Signal Decoders */
104 #define SELECT_RLD u8_encode_bits(0x0, REGISTER_SELECTION)
105 /* Counter Mode Register */
106 #define SELECT_CMR u8_encode_bits(0x1, REGISTER_SELECTION)
107 /* Input / Output Control Register */
108 #define SELECT_IOR u8_encode_bits(0x2, REGISTER_SELECTION)
109 /* Index Control Register */
110 #define SELECT_IDR u8_encode_bits(0x3, REGISTER_SELECTION)
111 
112 /*
113  * Reset and Load Signal Decoders
114  */
115 #define RESETS GENMASK(2, 1)
116 #define LOADS GENMASK(4, 3)
117 /* Reset Byte Pointer (three byte data pointer) */
118 #define RESET_BP BIT(0)
119 /* Reset Borrow Toggle, Carry toggle, Compare toggle, Sign, and Index flags */
120 #define RESET_BT_CT_CPT_S_IDX u8_encode_bits(0x2, RESETS)
121 /* Reset Error flag */
122 #define RESET_E u8_encode_bits(0x3, RESETS)
123 /* Preset Register to Counter */
124 #define TRANSFER_PR_TO_CNTR u8_encode_bits(0x1, LOADS)
125 /* Transfer Counter to Output Latch */
126 #define TRANSFER_CNTR_TO_OL u8_encode_bits(0x2, LOADS)
127 /* Transfer Preset Register LSB to FCK Prescaler */
128 #define TRANSFER_PR0_TO_PSC u8_encode_bits(0x3, LOADS)
129 
130 /*
131  * Counter Mode Registers
132  */
133 #define COUNT_ENCODING BIT(0)
134 #define COUNT_MODE GENMASK(2, 1)
135 #define QUADRATURE_MODE GENMASK(4, 3)
136 /* Binary count */
137 #define BINARY u8_encode_bits(0x0, COUNT_ENCODING)
138 /* Normal count */
139 #define NORMAL_COUNT 0x0
140 /* Range Limit */
141 #define RANGE_LIMIT 0x1
142 /* Non-recycle count */
143 #define NON_RECYCLE_COUNT 0x2
144 /* Modulo-N */
145 #define MODULO_N 0x3
146 /* Non-quadrature */
147 #define NON_QUADRATURE 0x0
148 /* Quadrature X1 */
149 #define QUADRATURE_X1 0x1
150 /* Quadrature X2 */
151 #define QUADRATURE_X2 0x2
152 /* Quadrature X4 */
153 #define QUADRATURE_X4 0x3
154 
155 /*
156  * Input/Output Control Register
157  */
158 #define AB_GATE BIT(0)
159 #define LOAD_PIN BIT(1)
160 #define FLG_PINS GENMASK(4, 3)
161 /* Disable inputs A and B */
162 #define DISABLE_AB u8_encode_bits(0x0, AB_GATE)
163 /* Load Counter input */
164 #define LOAD_CNTR 0x0
165 /* FLG1 = CARRY(active low); FLG2 = BORROW(active low) */
166 #define FLG1_CARRY_FLG2_BORROW 0x0
167 /* FLG1 = COMPARE(active low); FLG2 = BORROW(active low) */
168 #define FLG1_COMPARE_FLG2_BORROW 0x1
169 /* FLG1 = Carry(active low)/Borrow(active low); FLG2 = U/D(active low) flag */
170 #define FLG1_CARRYBORROW_FLG2_UD 0x2
171 /* FLG1 = INDX (low pulse at INDEX pin active level); FLG2 = E flag */
172 #define FLG1_INDX_FLG2_E 0x3
173 
174 /*
175  * INDEX CONTROL REGISTERS
176  */
177 #define INDEX_MODE BIT(0)
178 #define INDEX_POLARITY BIT(1)
179 /* Disable Index mode */
180 #define DISABLE_INDEX_MODE 0x0
181 /* Enable Index mode */
182 #define ENABLE_INDEX_MODE 0x1
183 /* Negative Index Polarity */
184 #define NEGATIVE_INDEX_POLARITY 0x0
185 /* Positive Index Polarity */
186 #define POSITIVE_INDEX_POLARITY 0x1
187 
188 /*
189  * Channel Operation Register
190  */
191 #define COUNTERS_OPERATION BIT(0)
192 #define INTERRUPT_FUNCTION BIT(2)
193 /* Enable all Counters */
194 #define ENABLE_COUNTERS u8_encode_bits(0x0, COUNTERS_OPERATION)
195 /* Reset all Counters */
196 #define RESET_COUNTERS u8_encode_bits(0x1, COUNTERS_OPERATION)
197 /* Disable the interrupt function */
198 #define DISABLE_INTERRUPT_FUNCTION u8_encode_bits(0x0, INTERRUPT_FUNCTION)
199 /* Enable the interrupt function */
200 #define ENABLE_INTERRUPT_FUNCTION u8_encode_bits(0x1, INTERRUPT_FUNCTION)
201 /* Any write to the Channel Operation register clears any pending interrupts */
202 #define CLEAR_PENDING_INTERRUPTS (ENABLE_COUNTERS | ENABLE_INTERRUPT_FUNCTION)
203 
204 /* Each Counter is 24 bits wide */
205 #define LS7267_CNTR_MAX GENMASK(23, 0)
206 
207 static __always_inline int quad8_control_register_update(struct regmap *const map, u8 *const buf,
208 							 const size_t channel, const u8 val,
209 							 const u8 field)
210 {
211 	u8p_replace_bits(&buf[channel], val, field);
212 	return regmap_write(map, QUAD8_CONTROL(channel), buf[channel]);
213 }
214 
215 static int quad8_signal_read(struct counter_device *counter,
216 			     struct counter_signal *signal,
217 			     enum counter_signal_level *level)
218 {
219 	const struct quad8 *const priv = counter_priv(counter);
220 	int ret;
221 
222 	/* Only Index signal levels can be read */
223 	if (signal->id < 16)
224 		return -EINVAL;
225 
226 	ret = regmap_test_bits(priv->map, QUAD8_INDEX_INPUT_LEVELS, BIT(signal->id - 16));
227 	if (ret < 0)
228 		return ret;
229 
230 	*level = (ret) ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
231 
232 	return 0;
233 }
234 
235 static int quad8_count_read(struct counter_device *counter,
236 			    struct counter_count *count, u64 *val)
237 {
238 	struct quad8 *const priv = counter_priv(counter);
239 	unsigned long irqflags;
240 	u8 value[3];
241 	int ret;
242 
243 	spin_lock_irqsave(&priv->lock, irqflags);
244 
245 	ret = regmap_write(priv->map, QUAD8_CONTROL(count->id),
246 			   SELECT_RLD | RESET_BP | TRANSFER_CNTR_TO_OL);
247 	if (ret)
248 		goto exit_unlock;
249 	ret = regmap_noinc_read(priv->map, QUAD8_DATA(count->id), value, sizeof(value));
250 
251 exit_unlock:
252 	spin_unlock_irqrestore(&priv->lock, irqflags);
253 
254 	*val = get_unaligned_le24(value);
255 
256 	return ret;
257 }
258 
259 static int quad8_preset_register_set(struct quad8 *const priv, const size_t id,
260 				     const unsigned long preset)
261 {
262 	u8 value[3];
263 	int ret;
264 
265 	put_unaligned_le24(preset, value);
266 
267 	ret = regmap_write(priv->map, QUAD8_CONTROL(id), SELECT_RLD | RESET_BP);
268 	if (ret)
269 		return ret;
270 	return regmap_noinc_write(priv->map, QUAD8_DATA(id), value, sizeof(value));
271 }
272 
273 static int quad8_flag_register_reset(struct quad8 *const priv, const size_t id)
274 {
275 	int ret;
276 
277 	ret = regmap_write(priv->map, QUAD8_CONTROL(id), SELECT_RLD | RESET_BT_CT_CPT_S_IDX);
278 	if (ret)
279 		return ret;
280 	return regmap_write(priv->map, QUAD8_CONTROL(id), SELECT_RLD | RESET_E);
281 }
282 
283 static int quad8_count_write(struct counter_device *counter,
284 			     struct counter_count *count, u64 val)
285 {
286 	struct quad8 *const priv = counter_priv(counter);
287 	unsigned long irqflags;
288 	int ret;
289 
290 	if (val > LS7267_CNTR_MAX)
291 		return -ERANGE;
292 
293 	spin_lock_irqsave(&priv->lock, irqflags);
294 
295 	/* Counter can only be set via Preset Register */
296 	ret = quad8_preset_register_set(priv, count->id, val);
297 	if (ret)
298 		goto exit_unlock;
299 	ret = regmap_write(priv->map, QUAD8_CONTROL(count->id), SELECT_RLD | TRANSFER_PR_TO_CNTR);
300 	if (ret)
301 		goto exit_unlock;
302 
303 	ret = quad8_flag_register_reset(priv, count->id);
304 	if (ret)
305 		goto exit_unlock;
306 
307 	/* Set Preset Register back to original value */
308 	ret = quad8_preset_register_set(priv, count->id, priv->preset[count->id]);
309 
310 exit_unlock:
311 	spin_unlock_irqrestore(&priv->lock, irqflags);
312 
313 	return ret;
314 }
315 
316 static const enum counter_function quad8_count_functions_list[] = {
317 	COUNTER_FUNCTION_PULSE_DIRECTION,
318 	COUNTER_FUNCTION_QUADRATURE_X1_A,
319 	COUNTER_FUNCTION_QUADRATURE_X2_A,
320 	COUNTER_FUNCTION_QUADRATURE_X4,
321 };
322 
323 static int quad8_function_get(const struct quad8 *const priv, const size_t id,
324 			      enum counter_function *const function)
325 {
326 	switch (u8_get_bits(priv->cmr[id], QUADRATURE_MODE)) {
327 	case NON_QUADRATURE:
328 		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
329 		return 0;
330 	case QUADRATURE_X1:
331 		*function = COUNTER_FUNCTION_QUADRATURE_X1_A;
332 		return 0;
333 	case QUADRATURE_X2:
334 		*function = COUNTER_FUNCTION_QUADRATURE_X2_A;
335 		return 0;
336 	case QUADRATURE_X4:
337 		*function = COUNTER_FUNCTION_QUADRATURE_X4;
338 		return 0;
339 	default:
340 		/* should never reach this path */
341 		return -EINVAL;
342 	}
343 }
344 
345 static int quad8_function_read(struct counter_device *counter,
346 			       struct counter_count *count,
347 			       enum counter_function *function)
348 {
349 	struct quad8 *const priv = counter_priv(counter);
350 	unsigned long irqflags;
351 	int retval;
352 
353 	spin_lock_irqsave(&priv->lock, irqflags);
354 
355 	retval = quad8_function_get(priv, count->id, function);
356 
357 	spin_unlock_irqrestore(&priv->lock, irqflags);
358 
359 	return retval;
360 }
361 
362 static int quad8_function_write(struct counter_device *counter,
363 				struct counter_count *count,
364 				enum counter_function function)
365 {
366 	struct quad8 *const priv = counter_priv(counter);
367 	const int id = count->id;
368 	unsigned long irqflags;
369 	unsigned int mode_cfg;
370 	bool synchronous_mode;
371 	int ret;
372 
373 	switch (function) {
374 	case COUNTER_FUNCTION_PULSE_DIRECTION:
375 		mode_cfg = NON_QUADRATURE;
376 		break;
377 	case COUNTER_FUNCTION_QUADRATURE_X1_A:
378 		mode_cfg = QUADRATURE_X1;
379 		break;
380 	case COUNTER_FUNCTION_QUADRATURE_X2_A:
381 		mode_cfg = QUADRATURE_X2;
382 		break;
383 	case COUNTER_FUNCTION_QUADRATURE_X4:
384 		mode_cfg = QUADRATURE_X4;
385 		break;
386 	default:
387 		/* should never reach this path */
388 		return -EINVAL;
389 	}
390 
391 	spin_lock_irqsave(&priv->lock, irqflags);
392 
393 	/* Synchronous function not supported in non-quadrature mode */
394 	synchronous_mode = u8_get_bits(priv->idr[id], INDEX_MODE) == ENABLE_INDEX_MODE;
395 	if (synchronous_mode && mode_cfg == NON_QUADRATURE) {
396 		ret = quad8_control_register_update(priv->map, priv->idr, id, DISABLE_INDEX_MODE,
397 						    INDEX_MODE);
398 		if (ret)
399 			goto exit_unlock;
400 	}
401 
402 	ret = quad8_control_register_update(priv->map, priv->cmr, id, mode_cfg, QUADRATURE_MODE);
403 
404 exit_unlock:
405 	spin_unlock_irqrestore(&priv->lock, irqflags);
406 
407 	return ret;
408 }
409 
410 static int quad8_direction_read(struct counter_device *counter,
411 				struct counter_count *count,
412 				enum counter_count_direction *direction)
413 {
414 	const struct quad8 *const priv = counter_priv(counter);
415 	unsigned int flag;
416 	int ret;
417 
418 	ret = regmap_read(priv->map, QUAD8_CONTROL(count->id), &flag);
419 	if (ret)
420 		return ret;
421 	*direction = (u8_get_bits(flag, FLAG_UD) == UP) ? COUNTER_COUNT_DIRECTION_FORWARD :
422 		COUNTER_COUNT_DIRECTION_BACKWARD;
423 
424 	return 0;
425 }
426 
427 static const enum counter_synapse_action quad8_index_actions_list[] = {
428 	COUNTER_SYNAPSE_ACTION_NONE,
429 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
430 };
431 
432 static const enum counter_synapse_action quad8_synapse_actions_list[] = {
433 	COUNTER_SYNAPSE_ACTION_NONE,
434 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
435 	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
436 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
437 };
438 
439 static int quad8_action_read(struct counter_device *counter,
440 			     struct counter_count *count,
441 			     struct counter_synapse *synapse,
442 			     enum counter_synapse_action *action)
443 {
444 	struct quad8 *const priv = counter_priv(counter);
445 	unsigned long irqflags;
446 	int err;
447 	enum counter_function function;
448 	const size_t signal_a_id = count->synapses[0].signal->id;
449 	enum counter_count_direction direction;
450 
451 	/* Default action mode */
452 	*action = COUNTER_SYNAPSE_ACTION_NONE;
453 
454 	/* Handle Index signals */
455 	if (synapse->signal->id >= 16) {
456 		if (u8_get_bits(priv->ior[count->id], LOAD_PIN) == LOAD_CNTR)
457 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
458 		return 0;
459 	}
460 
461 	spin_lock_irqsave(&priv->lock, irqflags);
462 
463 	/* Get Count function and direction atomically */
464 	err = quad8_function_get(priv, count->id, &function);
465 	if (err) {
466 		spin_unlock_irqrestore(&priv->lock, irqflags);
467 		return err;
468 	}
469 	err = quad8_direction_read(counter, count, &direction);
470 	if (err) {
471 		spin_unlock_irqrestore(&priv->lock, irqflags);
472 		return err;
473 	}
474 
475 	spin_unlock_irqrestore(&priv->lock, irqflags);
476 
477 	/* Determine action mode based on current count function mode */
478 	switch (function) {
479 	case COUNTER_FUNCTION_PULSE_DIRECTION:
480 		if (synapse->signal->id == signal_a_id)
481 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
482 		return 0;
483 	case COUNTER_FUNCTION_QUADRATURE_X1_A:
484 		if (synapse->signal->id == signal_a_id) {
485 			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
486 				*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
487 			else
488 				*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
489 		}
490 		return 0;
491 	case COUNTER_FUNCTION_QUADRATURE_X2_A:
492 		if (synapse->signal->id == signal_a_id)
493 			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
494 		return 0;
495 	case COUNTER_FUNCTION_QUADRATURE_X4:
496 		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
497 		return 0;
498 	default:
499 		/* should never reach this path */
500 		return -EINVAL;
501 	}
502 }
503 
504 static int quad8_events_configure(struct counter_device *counter)
505 {
506 	struct quad8 *const priv = counter_priv(counter);
507 	unsigned long irq_enabled = 0;
508 	unsigned long irqflags;
509 	struct counter_event_node *event_node;
510 	u8 flg_pins;
511 	int ret;
512 
513 	spin_lock_irqsave(&priv->lock, irqflags);
514 
515 	list_for_each_entry(event_node, &counter->events_list, l) {
516 		switch (event_node->event) {
517 		case COUNTER_EVENT_OVERFLOW:
518 			flg_pins = FLG1_CARRY_FLG2_BORROW;
519 			break;
520 		case COUNTER_EVENT_THRESHOLD:
521 			flg_pins = FLG1_COMPARE_FLG2_BORROW;
522 			break;
523 		case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
524 			flg_pins = FLG1_CARRYBORROW_FLG2_UD;
525 			break;
526 		case COUNTER_EVENT_INDEX:
527 			flg_pins = FLG1_INDX_FLG2_E;
528 			break;
529 		default:
530 			/* should never reach this path */
531 			ret = -EINVAL;
532 			goto exit_unlock;
533 		}
534 
535 		/* Enable IRQ line */
536 		irq_enabled |= BIT(event_node->channel);
537 
538 		/* Skip configuration if it is the same as previously set */
539 		if (flg_pins == u8_get_bits(priv->ior[event_node->channel], FLG_PINS))
540 			continue;
541 
542 		/* Save new IRQ function configuration */
543 		ret = quad8_control_register_update(priv->map, priv->ior, event_node->channel,
544 						    flg_pins, FLG_PINS);
545 		if (ret)
546 			goto exit_unlock;
547 	}
548 
549 	ret = regmap_write(priv->map, QUAD8_INDEX_INTERRUPT, irq_enabled);
550 
551 exit_unlock:
552 	spin_unlock_irqrestore(&priv->lock, irqflags);
553 
554 	return ret;
555 }
556 
557 static int quad8_watch_validate(struct counter_device *counter,
558 				const struct counter_watch *watch)
559 {
560 	struct counter_event_node *event_node;
561 
562 	if (watch->channel > QUAD8_NUM_COUNTERS - 1)
563 		return -EINVAL;
564 
565 	switch (watch->event) {
566 	case COUNTER_EVENT_OVERFLOW:
567 	case COUNTER_EVENT_THRESHOLD:
568 	case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
569 	case COUNTER_EVENT_INDEX:
570 		list_for_each_entry(event_node, &counter->next_events_list, l)
571 			if (watch->channel == event_node->channel &&
572 				watch->event != event_node->event)
573 				return -EINVAL;
574 		return 0;
575 	default:
576 		return -EINVAL;
577 	}
578 }
579 
580 static const struct counter_ops quad8_ops = {
581 	.signal_read = quad8_signal_read,
582 	.count_read = quad8_count_read,
583 	.count_write = quad8_count_write,
584 	.function_read = quad8_function_read,
585 	.function_write = quad8_function_write,
586 	.action_read = quad8_action_read,
587 	.events_configure = quad8_events_configure,
588 	.watch_validate = quad8_watch_validate,
589 };
590 
591 static const char *const quad8_index_polarity_modes[] = {
592 	"negative",
593 	"positive"
594 };
595 
596 static int quad8_index_polarity_get(struct counter_device *counter,
597 				    struct counter_signal *signal,
598 				    u32 *index_polarity)
599 {
600 	const struct quad8 *const priv = counter_priv(counter);
601 	const size_t channel_id = signal->id - 16;
602 
603 	*index_polarity = u8_get_bits(priv->idr[channel_id], INDEX_POLARITY);
604 
605 	return 0;
606 }
607 
608 static int quad8_index_polarity_set(struct counter_device *counter,
609 				    struct counter_signal *signal,
610 				    u32 index_polarity)
611 {
612 	struct quad8 *const priv = counter_priv(counter);
613 	const size_t channel_id = signal->id - 16;
614 	unsigned long irqflags;
615 	int ret;
616 
617 	spin_lock_irqsave(&priv->lock, irqflags);
618 
619 	ret = quad8_control_register_update(priv->map, priv->idr, channel_id, index_polarity,
620 					    INDEX_POLARITY);
621 
622 	spin_unlock_irqrestore(&priv->lock, irqflags);
623 
624 	return ret;
625 }
626 
627 static int quad8_polarity_read(struct counter_device *counter,
628 			       struct counter_signal *signal,
629 			       enum counter_signal_polarity *polarity)
630 {
631 	int err;
632 	u32 index_polarity;
633 
634 	err = quad8_index_polarity_get(counter, signal, &index_polarity);
635 	if (err)
636 		return err;
637 
638 	*polarity = (index_polarity == POSITIVE_INDEX_POLARITY) ? COUNTER_SIGNAL_POLARITY_POSITIVE :
639 		COUNTER_SIGNAL_POLARITY_NEGATIVE;
640 
641 	return 0;
642 }
643 
644 static int quad8_polarity_write(struct counter_device *counter,
645 				struct counter_signal *signal,
646 				enum counter_signal_polarity polarity)
647 {
648 	const u32 pol = (polarity == COUNTER_SIGNAL_POLARITY_POSITIVE) ? POSITIVE_INDEX_POLARITY :
649 									 NEGATIVE_INDEX_POLARITY;
650 
651 	return quad8_index_polarity_set(counter, signal, pol);
652 }
653 
654 static const char *const quad8_synchronous_modes[] = {
655 	"non-synchronous",
656 	"synchronous"
657 };
658 
659 static int quad8_synchronous_mode_get(struct counter_device *counter,
660 				      struct counter_signal *signal,
661 				      u32 *synchronous_mode)
662 {
663 	const struct quad8 *const priv = counter_priv(counter);
664 	const size_t channel_id = signal->id - 16;
665 
666 	*synchronous_mode = u8_get_bits(priv->idr[channel_id], INDEX_MODE);
667 
668 	return 0;
669 }
670 
671 static int quad8_synchronous_mode_set(struct counter_device *counter,
672 				      struct counter_signal *signal,
673 				      u32 synchronous_mode)
674 {
675 	struct quad8 *const priv = counter_priv(counter);
676 	const size_t channel_id = signal->id - 16;
677 	u8 quadrature_mode;
678 	unsigned long irqflags;
679 	int ret;
680 
681 	spin_lock_irqsave(&priv->lock, irqflags);
682 
683 	/* Index function must be non-synchronous in non-quadrature mode */
684 	quadrature_mode = u8_get_bits(priv->idr[channel_id], QUADRATURE_MODE);
685 	if (synchronous_mode && quadrature_mode == NON_QUADRATURE) {
686 		ret = -EINVAL;
687 		goto exit_unlock;
688 	}
689 
690 	ret = quad8_control_register_update(priv->map, priv->idr, channel_id, synchronous_mode,
691 					    INDEX_MODE);
692 
693 exit_unlock:
694 	spin_unlock_irqrestore(&priv->lock, irqflags);
695 
696 	return ret;
697 }
698 
699 static int quad8_count_floor_read(struct counter_device *counter,
700 				  struct counter_count *count, u64 *floor)
701 {
702 	/* Only a floor of 0 is supported */
703 	*floor = 0;
704 
705 	return 0;
706 }
707 
708 static int quad8_count_mode_read(struct counter_device *counter,
709 				 struct counter_count *count,
710 				 enum counter_count_mode *cnt_mode)
711 {
712 	const struct quad8 *const priv = counter_priv(counter);
713 
714 	switch (u8_get_bits(priv->cmr[count->id], COUNT_MODE)) {
715 	case NORMAL_COUNT:
716 		*cnt_mode = COUNTER_COUNT_MODE_NORMAL;
717 		break;
718 	case RANGE_LIMIT:
719 		*cnt_mode = COUNTER_COUNT_MODE_RANGE_LIMIT;
720 		break;
721 	case NON_RECYCLE_COUNT:
722 		*cnt_mode = COUNTER_COUNT_MODE_NON_RECYCLE;
723 		break;
724 	case MODULO_N:
725 		*cnt_mode = COUNTER_COUNT_MODE_MODULO_N;
726 		break;
727 	}
728 
729 	return 0;
730 }
731 
732 static int quad8_count_mode_write(struct counter_device *counter,
733 				  struct counter_count *count,
734 				  enum counter_count_mode cnt_mode)
735 {
736 	struct quad8 *const priv = counter_priv(counter);
737 	unsigned int count_mode;
738 	unsigned long irqflags;
739 	int ret;
740 
741 	switch (cnt_mode) {
742 	case COUNTER_COUNT_MODE_NORMAL:
743 		count_mode = NORMAL_COUNT;
744 		break;
745 	case COUNTER_COUNT_MODE_RANGE_LIMIT:
746 		count_mode = RANGE_LIMIT;
747 		break;
748 	case COUNTER_COUNT_MODE_NON_RECYCLE:
749 		count_mode = NON_RECYCLE_COUNT;
750 		break;
751 	case COUNTER_COUNT_MODE_MODULO_N:
752 		count_mode = MODULO_N;
753 		break;
754 	default:
755 		/* should never reach this path */
756 		return -EINVAL;
757 	}
758 
759 	spin_lock_irqsave(&priv->lock, irqflags);
760 
761 	ret = quad8_control_register_update(priv->map, priv->cmr, count->id, count_mode,
762 					    COUNT_MODE);
763 
764 	spin_unlock_irqrestore(&priv->lock, irqflags);
765 
766 	return ret;
767 }
768 
769 static int quad8_count_enable_read(struct counter_device *counter,
770 				   struct counter_count *count, u8 *enable)
771 {
772 	const struct quad8 *const priv = counter_priv(counter);
773 
774 	*enable = u8_get_bits(priv->ior[count->id], AB_GATE);
775 
776 	return 0;
777 }
778 
779 static int quad8_count_enable_write(struct counter_device *counter,
780 				    struct counter_count *count, u8 enable)
781 {
782 	struct quad8 *const priv = counter_priv(counter);
783 	unsigned long irqflags;
784 	int ret;
785 
786 	spin_lock_irqsave(&priv->lock, irqflags);
787 
788 	ret = quad8_control_register_update(priv->map, priv->ior, count->id, enable, AB_GATE);
789 
790 	spin_unlock_irqrestore(&priv->lock, irqflags);
791 
792 	return ret;
793 }
794 
795 static const char *const quad8_noise_error_states[] = {
796 	"No excessive noise is present at the count inputs",
797 	"Excessive noise is present at the count inputs"
798 };
799 
800 static int quad8_error_noise_get(struct counter_device *counter,
801 				 struct counter_count *count, u32 *noise_error)
802 {
803 	const struct quad8 *const priv = counter_priv(counter);
804 	unsigned int flag;
805 	int ret;
806 
807 	ret = regmap_read(priv->map, QUAD8_CONTROL(count->id), &flag);
808 	if (ret)
809 		return ret;
810 	*noise_error = u8_get_bits(flag, FLAG_E);
811 
812 	return 0;
813 }
814 
815 static int quad8_count_preset_read(struct counter_device *counter,
816 				   struct counter_count *count, u64 *preset)
817 {
818 	const struct quad8 *const priv = counter_priv(counter);
819 
820 	*preset = priv->preset[count->id];
821 
822 	return 0;
823 }
824 
825 static int quad8_count_preset_write(struct counter_device *counter,
826 				    struct counter_count *count, u64 preset)
827 {
828 	struct quad8 *const priv = counter_priv(counter);
829 	unsigned long irqflags;
830 	int ret;
831 
832 	if (preset > LS7267_CNTR_MAX)
833 		return -ERANGE;
834 
835 	spin_lock_irqsave(&priv->lock, irqflags);
836 
837 	priv->preset[count->id] = preset;
838 	ret = quad8_preset_register_set(priv, count->id, preset);
839 
840 	spin_unlock_irqrestore(&priv->lock, irqflags);
841 
842 	return ret;
843 }
844 
845 static int quad8_count_ceiling_read(struct counter_device *counter,
846 				    struct counter_count *count, u64 *ceiling)
847 {
848 	struct quad8 *const priv = counter_priv(counter);
849 	unsigned long irqflags;
850 
851 	spin_lock_irqsave(&priv->lock, irqflags);
852 
853 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
854 	switch (u8_get_bits(priv->cmr[count->id], COUNT_MODE)) {
855 	case RANGE_LIMIT:
856 	case MODULO_N:
857 		*ceiling = priv->preset[count->id];
858 		break;
859 	default:
860 		*ceiling = LS7267_CNTR_MAX;
861 		break;
862 	}
863 
864 	spin_unlock_irqrestore(&priv->lock, irqflags);
865 
866 	return 0;
867 }
868 
869 static int quad8_count_ceiling_write(struct counter_device *counter,
870 				     struct counter_count *count, u64 ceiling)
871 {
872 	struct quad8 *const priv = counter_priv(counter);
873 	unsigned long irqflags;
874 	int ret;
875 
876 	if (ceiling > LS7267_CNTR_MAX)
877 		return -ERANGE;
878 
879 	spin_lock_irqsave(&priv->lock, irqflags);
880 
881 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
882 	switch (u8_get_bits(priv->cmr[count->id], COUNT_MODE)) {
883 	case RANGE_LIMIT:
884 	case MODULO_N:
885 		priv->preset[count->id] = ceiling;
886 		ret = quad8_preset_register_set(priv, count->id, ceiling);
887 		break;
888 	default:
889 		ret = -EINVAL;
890 		break;
891 	}
892 
893 	spin_unlock_irqrestore(&priv->lock, irqflags);
894 
895 	return ret;
896 }
897 
898 static int quad8_count_preset_enable_read(struct counter_device *counter,
899 					  struct counter_count *count,
900 					  u8 *preset_enable)
901 {
902 	const struct quad8 *const priv = counter_priv(counter);
903 
904 	/* Preset enable is active low in Input/Output Control register */
905 	*preset_enable = !u8_get_bits(priv->ior[count->id], LOAD_PIN);
906 
907 	return 0;
908 }
909 
910 static int quad8_count_preset_enable_write(struct counter_device *counter,
911 					   struct counter_count *count,
912 					   u8 preset_enable)
913 {
914 	struct quad8 *const priv = counter_priv(counter);
915 	unsigned long irqflags;
916 	int ret;
917 
918 	spin_lock_irqsave(&priv->lock, irqflags);
919 
920 	/* Preset enable is active low in Input/Output Control register */
921 	ret = quad8_control_register_update(priv->map, priv->ior, count->id, !preset_enable,
922 					    LOAD_PIN);
923 
924 	spin_unlock_irqrestore(&priv->lock, irqflags);
925 
926 	return ret;
927 }
928 
929 static int quad8_signal_cable_fault_read(struct counter_device *counter,
930 					 struct counter_signal *signal,
931 					 u8 *cable_fault)
932 {
933 	struct quad8 *const priv = counter_priv(counter);
934 	const size_t channel_id = signal->id / 2;
935 	unsigned long irqflags;
936 	bool disabled;
937 	int ret;
938 
939 	spin_lock_irqsave(&priv->lock, irqflags);
940 
941 	disabled = !(priv->cable_fault_enable & BIT(channel_id));
942 
943 	if (disabled) {
944 		spin_unlock_irqrestore(&priv->lock, irqflags);
945 		return -EINVAL;
946 	}
947 
948 	ret = regmap_test_bits(priv->map, QUAD8_CABLE_STATUS, BIT(channel_id));
949 	if (ret < 0) {
950 		spin_unlock_irqrestore(&priv->lock, irqflags);
951 		return ret;
952 	}
953 
954 	spin_unlock_irqrestore(&priv->lock, irqflags);
955 
956 	/* Logic 0 = cable fault */
957 	*cable_fault = !ret;
958 
959 	return 0;
960 }
961 
962 static int quad8_signal_cable_fault_enable_read(struct counter_device *counter,
963 						struct counter_signal *signal,
964 						u8 *enable)
965 {
966 	const struct quad8 *const priv = counter_priv(counter);
967 	const size_t channel_id = signal->id / 2;
968 
969 	*enable = !!(priv->cable_fault_enable & BIT(channel_id));
970 
971 	return 0;
972 }
973 
974 static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
975 						 struct counter_signal *signal,
976 						 u8 enable)
977 {
978 	struct quad8 *const priv = counter_priv(counter);
979 	const size_t channel_id = signal->id / 2;
980 	unsigned long irqflags;
981 	unsigned int cable_fault_enable;
982 	int ret;
983 
984 	spin_lock_irqsave(&priv->lock, irqflags);
985 
986 	if (enable)
987 		priv->cable_fault_enable |= BIT(channel_id);
988 	else
989 		priv->cable_fault_enable &= ~BIT(channel_id);
990 
991 	/* Enable is active low in Differential Encoder Cable Status register */
992 	cable_fault_enable = ~priv->cable_fault_enable;
993 
994 	ret = regmap_write(priv->map, QUAD8_CABLE_STATUS, cable_fault_enable);
995 
996 	spin_unlock_irqrestore(&priv->lock, irqflags);
997 
998 	return ret;
999 }
1000 
1001 static int quad8_signal_fck_prescaler_read(struct counter_device *counter,
1002 					   struct counter_signal *signal,
1003 					   u8 *prescaler)
1004 {
1005 	const struct quad8 *const priv = counter_priv(counter);
1006 
1007 	*prescaler = priv->fck_prescaler[signal->id / 2];
1008 
1009 	return 0;
1010 }
1011 
1012 static int quad8_filter_clock_prescaler_set(struct quad8 *const priv, const size_t id,
1013 					    const u8 prescaler)
1014 {
1015 	int ret;
1016 
1017 	ret = regmap_write(priv->map, QUAD8_CONTROL(id), SELECT_RLD | RESET_BP);
1018 	if (ret)
1019 		return ret;
1020 	ret = regmap_write(priv->map, QUAD8_DATA(id), prescaler);
1021 	if (ret)
1022 		return ret;
1023 	return regmap_write(priv->map, QUAD8_CONTROL(id), SELECT_RLD | TRANSFER_PR0_TO_PSC);
1024 }
1025 
1026 static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
1027 					    struct counter_signal *signal,
1028 					    u8 prescaler)
1029 {
1030 	struct quad8 *const priv = counter_priv(counter);
1031 	const size_t channel_id = signal->id / 2;
1032 	unsigned long irqflags;
1033 	int ret;
1034 
1035 	spin_lock_irqsave(&priv->lock, irqflags);
1036 
1037 	priv->fck_prescaler[channel_id] = prescaler;
1038 	ret = quad8_filter_clock_prescaler_set(priv, channel_id, prescaler);
1039 
1040 	spin_unlock_irqrestore(&priv->lock, irqflags);
1041 
1042 	return ret;
1043 }
1044 
1045 static struct counter_comp quad8_signal_ext[] = {
1046 	COUNTER_COMP_SIGNAL_BOOL("cable_fault", quad8_signal_cable_fault_read,
1047 				 NULL),
1048 	COUNTER_COMP_SIGNAL_BOOL("cable_fault_enable",
1049 				 quad8_signal_cable_fault_enable_read,
1050 				 quad8_signal_cable_fault_enable_write),
1051 	COUNTER_COMP_SIGNAL_U8("filter_clock_prescaler",
1052 			       quad8_signal_fck_prescaler_read,
1053 			       quad8_signal_fck_prescaler_write)
1054 };
1055 
1056 static const enum counter_signal_polarity quad8_polarities[] = {
1057 	COUNTER_SIGNAL_POLARITY_POSITIVE,
1058 	COUNTER_SIGNAL_POLARITY_NEGATIVE,
1059 };
1060 
1061 static DEFINE_COUNTER_AVAILABLE(quad8_polarity_available, quad8_polarities);
1062 
1063 static DEFINE_COUNTER_ENUM(quad8_index_pol_enum, quad8_index_polarity_modes);
1064 static DEFINE_COUNTER_ENUM(quad8_synch_mode_enum, quad8_synchronous_modes);
1065 
1066 static struct counter_comp quad8_index_ext[] = {
1067 	COUNTER_COMP_SIGNAL_ENUM("index_polarity", quad8_index_polarity_get,
1068 				 quad8_index_polarity_set,
1069 				 quad8_index_pol_enum),
1070 	COUNTER_COMP_POLARITY(quad8_polarity_read, quad8_polarity_write,
1071 			      quad8_polarity_available),
1072 	COUNTER_COMP_SIGNAL_ENUM("synchronous_mode", quad8_synchronous_mode_get,
1073 				 quad8_synchronous_mode_set,
1074 				 quad8_synch_mode_enum),
1075 };
1076 
1077 #define QUAD8_QUAD_SIGNAL(_id, _name) {		\
1078 	.id = (_id),				\
1079 	.name = (_name),			\
1080 	.ext = quad8_signal_ext,		\
1081 	.num_ext = ARRAY_SIZE(quad8_signal_ext)	\
1082 }
1083 
1084 #define	QUAD8_INDEX_SIGNAL(_id, _name) {	\
1085 	.id = (_id),				\
1086 	.name = (_name),			\
1087 	.ext = quad8_index_ext,			\
1088 	.num_ext = ARRAY_SIZE(quad8_index_ext)	\
1089 }
1090 
1091 static struct counter_signal quad8_signals[] = {
1092 	QUAD8_QUAD_SIGNAL(0, "Channel 1 Quadrature A"),
1093 	QUAD8_QUAD_SIGNAL(1, "Channel 1 Quadrature B"),
1094 	QUAD8_QUAD_SIGNAL(2, "Channel 2 Quadrature A"),
1095 	QUAD8_QUAD_SIGNAL(3, "Channel 2 Quadrature B"),
1096 	QUAD8_QUAD_SIGNAL(4, "Channel 3 Quadrature A"),
1097 	QUAD8_QUAD_SIGNAL(5, "Channel 3 Quadrature B"),
1098 	QUAD8_QUAD_SIGNAL(6, "Channel 4 Quadrature A"),
1099 	QUAD8_QUAD_SIGNAL(7, "Channel 4 Quadrature B"),
1100 	QUAD8_QUAD_SIGNAL(8, "Channel 5 Quadrature A"),
1101 	QUAD8_QUAD_SIGNAL(9, "Channel 5 Quadrature B"),
1102 	QUAD8_QUAD_SIGNAL(10, "Channel 6 Quadrature A"),
1103 	QUAD8_QUAD_SIGNAL(11, "Channel 6 Quadrature B"),
1104 	QUAD8_QUAD_SIGNAL(12, "Channel 7 Quadrature A"),
1105 	QUAD8_QUAD_SIGNAL(13, "Channel 7 Quadrature B"),
1106 	QUAD8_QUAD_SIGNAL(14, "Channel 8 Quadrature A"),
1107 	QUAD8_QUAD_SIGNAL(15, "Channel 8 Quadrature B"),
1108 	QUAD8_INDEX_SIGNAL(16, "Channel 1 Index"),
1109 	QUAD8_INDEX_SIGNAL(17, "Channel 2 Index"),
1110 	QUAD8_INDEX_SIGNAL(18, "Channel 3 Index"),
1111 	QUAD8_INDEX_SIGNAL(19, "Channel 4 Index"),
1112 	QUAD8_INDEX_SIGNAL(20, "Channel 5 Index"),
1113 	QUAD8_INDEX_SIGNAL(21, "Channel 6 Index"),
1114 	QUAD8_INDEX_SIGNAL(22, "Channel 7 Index"),
1115 	QUAD8_INDEX_SIGNAL(23, "Channel 8 Index")
1116 };
1117 
1118 #define QUAD8_COUNT_SYNAPSES(_id) {					\
1119 	{								\
1120 		.actions_list = quad8_synapse_actions_list,		\
1121 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1122 		.signal = quad8_signals + 2 * (_id)			\
1123 	},								\
1124 	{								\
1125 		.actions_list = quad8_synapse_actions_list,		\
1126 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1127 		.signal = quad8_signals + 2 * (_id) + 1			\
1128 	},								\
1129 	{								\
1130 		.actions_list = quad8_index_actions_list,		\
1131 		.num_actions = ARRAY_SIZE(quad8_index_actions_list),	\
1132 		.signal = quad8_signals + 2 * (_id) + 16		\
1133 	}								\
1134 }
1135 
1136 static struct counter_synapse quad8_count_synapses[][3] = {
1137 	QUAD8_COUNT_SYNAPSES(0), QUAD8_COUNT_SYNAPSES(1),
1138 	QUAD8_COUNT_SYNAPSES(2), QUAD8_COUNT_SYNAPSES(3),
1139 	QUAD8_COUNT_SYNAPSES(4), QUAD8_COUNT_SYNAPSES(5),
1140 	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
1141 };
1142 
1143 static const enum counter_count_mode quad8_cnt_modes[] = {
1144 	COUNTER_COUNT_MODE_NORMAL,
1145 	COUNTER_COUNT_MODE_RANGE_LIMIT,
1146 	COUNTER_COUNT_MODE_NON_RECYCLE,
1147 	COUNTER_COUNT_MODE_MODULO_N,
1148 };
1149 
1150 static DEFINE_COUNTER_AVAILABLE(quad8_count_mode_available, quad8_cnt_modes);
1151 
1152 static DEFINE_COUNTER_ENUM(quad8_error_noise_enum, quad8_noise_error_states);
1153 
1154 static struct counter_comp quad8_count_ext[] = {
1155 	COUNTER_COMP_CEILING(quad8_count_ceiling_read,
1156 			     quad8_count_ceiling_write),
1157 	COUNTER_COMP_FLOOR(quad8_count_floor_read, NULL),
1158 	COUNTER_COMP_COUNT_MODE(quad8_count_mode_read, quad8_count_mode_write,
1159 				quad8_count_mode_available),
1160 	COUNTER_COMP_DIRECTION(quad8_direction_read),
1161 	COUNTER_COMP_ENABLE(quad8_count_enable_read, quad8_count_enable_write),
1162 	COUNTER_COMP_COUNT_ENUM("error_noise", quad8_error_noise_get, NULL,
1163 				quad8_error_noise_enum),
1164 	COUNTER_COMP_PRESET(quad8_count_preset_read, quad8_count_preset_write),
1165 	COUNTER_COMP_PRESET_ENABLE(quad8_count_preset_enable_read,
1166 				   quad8_count_preset_enable_write),
1167 };
1168 
1169 #define QUAD8_COUNT(_id, _cntname) {					\
1170 	.id = (_id),							\
1171 	.name = (_cntname),						\
1172 	.functions_list = quad8_count_functions_list,			\
1173 	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
1174 	.synapses = quad8_count_synapses[(_id)],			\
1175 	.num_synapses =	2,						\
1176 	.ext = quad8_count_ext,						\
1177 	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
1178 }
1179 
1180 static struct counter_count quad8_counts[] = {
1181 	QUAD8_COUNT(0, "Channel 1 Count"),
1182 	QUAD8_COUNT(1, "Channel 2 Count"),
1183 	QUAD8_COUNT(2, "Channel 3 Count"),
1184 	QUAD8_COUNT(3, "Channel 4 Count"),
1185 	QUAD8_COUNT(4, "Channel 5 Count"),
1186 	QUAD8_COUNT(5, "Channel 6 Count"),
1187 	QUAD8_COUNT(6, "Channel 7 Count"),
1188 	QUAD8_COUNT(7, "Channel 8 Count")
1189 };
1190 
1191 static irqreturn_t quad8_irq_handler(int irq, void *private)
1192 {
1193 	struct counter_device *counter = private;
1194 	struct quad8 *const priv = counter_priv(counter);
1195 	unsigned int status;
1196 	unsigned long irq_status;
1197 	unsigned long channel;
1198 	unsigned int flg_pins;
1199 	u8 event;
1200 	int ret;
1201 
1202 	ret = regmap_read(priv->map, QUAD8_INTERRUPT_STATUS, &status);
1203 	if (ret)
1204 		return ret;
1205 	if (!status)
1206 		return IRQ_NONE;
1207 
1208 	irq_status = status;
1209 	for_each_set_bit(channel, &irq_status, QUAD8_NUM_COUNTERS) {
1210 		flg_pins = u8_get_bits(priv->ior[channel], FLG_PINS);
1211 		switch (flg_pins) {
1212 		case FLG1_CARRY_FLG2_BORROW:
1213 			event = COUNTER_EVENT_OVERFLOW;
1214 				break;
1215 		case FLG1_COMPARE_FLG2_BORROW:
1216 			event = COUNTER_EVENT_THRESHOLD;
1217 				break;
1218 		case FLG1_CARRYBORROW_FLG2_UD:
1219 			event = COUNTER_EVENT_OVERFLOW_UNDERFLOW;
1220 				break;
1221 		case FLG1_INDX_FLG2_E:
1222 			event = COUNTER_EVENT_INDEX;
1223 				break;
1224 		default:
1225 			/* should never reach this path */
1226 			WARN_ONCE(true, "invalid interrupt trigger function %u configured for channel %lu\n",
1227 				  flg_pins, channel);
1228 			continue;
1229 		}
1230 
1231 		counter_push_event(counter, event, channel);
1232 	}
1233 
1234 	ret = regmap_write(priv->map, QUAD8_CHANNEL_OPERATION, CLEAR_PENDING_INTERRUPTS);
1235 	if (ret)
1236 		return ret;
1237 
1238 	return IRQ_HANDLED;
1239 }
1240 
1241 static int quad8_init_counter(struct quad8 *const priv, const size_t channel)
1242 {
1243 	int ret;
1244 
1245 	ret = quad8_filter_clock_prescaler_set(priv, channel, 0);
1246 	if (ret)
1247 		return ret;
1248 	ret = quad8_preset_register_set(priv, channel, 0);
1249 	if (ret)
1250 		return ret;
1251 	ret = quad8_flag_register_reset(priv, channel);
1252 	if (ret)
1253 		return ret;
1254 
1255 	/* Binary encoding; Normal count; non-quadrature mode */
1256 	priv->cmr[channel] = SELECT_CMR | BINARY | u8_encode_bits(NORMAL_COUNT, COUNT_MODE) |
1257 			     u8_encode_bits(NON_QUADRATURE, QUADRATURE_MODE);
1258 	ret = regmap_write(priv->map, QUAD8_CONTROL(channel), priv->cmr[channel]);
1259 	if (ret)
1260 		return ret;
1261 
1262 	/* Disable A and B inputs; preset on index; FLG1 as Carry */
1263 	priv->ior[channel] = SELECT_IOR | DISABLE_AB | u8_encode_bits(LOAD_CNTR, LOAD_PIN) |
1264 			     u8_encode_bits(FLG1_CARRY_FLG2_BORROW, FLG_PINS);
1265 	ret = regmap_write(priv->map, QUAD8_CONTROL(channel), priv->ior[channel]);
1266 	if (ret)
1267 		return ret;
1268 
1269 	/* Disable index function; negative index polarity */
1270 	priv->idr[channel] = SELECT_IDR | u8_encode_bits(DISABLE_INDEX_MODE, INDEX_MODE) |
1271 			     u8_encode_bits(NEGATIVE_INDEX_POLARITY, INDEX_POLARITY);
1272 	return regmap_write(priv->map, QUAD8_CONTROL(channel), priv->idr[channel]);
1273 }
1274 
1275 static int quad8_probe(struct device *dev, unsigned int id)
1276 {
1277 	struct counter_device *counter;
1278 	struct quad8 *priv;
1279 	void __iomem *regs;
1280 	unsigned long i;
1281 	int ret;
1282 
1283 	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
1284 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
1285 			base[id], base[id] + QUAD8_EXTENT);
1286 		return -EBUSY;
1287 	}
1288 
1289 	counter = devm_counter_alloc(dev, sizeof(*priv));
1290 	if (!counter)
1291 		return -ENOMEM;
1292 	priv = counter_priv(counter);
1293 
1294 	regs = devm_ioport_map(dev, base[id], QUAD8_EXTENT);
1295 	if (!regs)
1296 		return -ENOMEM;
1297 
1298 	priv->map = devm_regmap_init_mmio(dev, regs, &quad8_regmap_config);
1299 	if (IS_ERR(priv->map))
1300 		return dev_err_probe(dev, PTR_ERR(priv->map),
1301 				     "Unable to initialize register map\n");
1302 
1303 	/* Initialize Counter device and driver data */
1304 	counter->name = dev_name(dev);
1305 	counter->parent = dev;
1306 	counter->ops = &quad8_ops;
1307 	counter->counts = quad8_counts;
1308 	counter->num_counts = ARRAY_SIZE(quad8_counts);
1309 	counter->signals = quad8_signals;
1310 	counter->num_signals = ARRAY_SIZE(quad8_signals);
1311 
1312 	spin_lock_init(&priv->lock);
1313 
1314 	/* Reset Index/Interrupt Register */
1315 	ret = regmap_write(priv->map, QUAD8_INDEX_INTERRUPT, 0x00);
1316 	if (ret)
1317 		return ret;
1318 	/* Reset all counters and disable interrupt function */
1319 	ret = regmap_write(priv->map, QUAD8_CHANNEL_OPERATION,
1320 			   RESET_COUNTERS | DISABLE_INTERRUPT_FUNCTION);
1321 	if (ret)
1322 		return ret;
1323 	/* Set initial configuration for all counters */
1324 	for (i = 0; i < QUAD8_NUM_COUNTERS; i++) {
1325 		ret = quad8_init_counter(priv, i);
1326 		if (ret)
1327 			return ret;
1328 	}
1329 	/* Disable Differential Encoder Cable Status for all channels */
1330 	ret = regmap_write(priv->map, QUAD8_CABLE_STATUS, GENMASK(7, 0));
1331 	if (ret)
1332 		return ret;
1333 	/* Enable all counters and enable interrupt function */
1334 	ret = regmap_write(priv->map, QUAD8_CHANNEL_OPERATION,
1335 			   ENABLE_COUNTERS | ENABLE_INTERRUPT_FUNCTION);
1336 	if (ret)
1337 		return ret;
1338 
1339 	ret = devm_request_irq(&counter->dev, irq[id], quad8_irq_handler,
1340 			       IRQF_SHARED, counter->name, counter);
1341 	if (ret)
1342 		return ret;
1343 
1344 	ret = devm_counter_add(dev, counter);
1345 	if (ret < 0)
1346 		return dev_err_probe(dev, ret, "Failed to add counter\n");
1347 
1348 	return 0;
1349 }
1350 
1351 static struct isa_driver quad8_driver = {
1352 	.probe = quad8_probe,
1353 	.driver = {
1354 		.name = "104-quad-8"
1355 	}
1356 };
1357 
1358 module_isa_driver_with_irq(quad8_driver, num_quad8, num_irq);
1359 
1360 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
1361 MODULE_DESCRIPTION("ACCES 104-QUAD-8 driver");
1362 MODULE_LICENSE("GPL v2");
1363 MODULE_IMPORT_NS(COUNTER);
1364