xref: /openbmc/linux/drivers/counter/104-quad-8.c (revision 10756dc5)
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/bitops.h>
9 #include <linux/counter.h>
10 #include <linux/device.h>
11 #include <linux/errno.h>
12 #include <linux/io.h>
13 #include <linux/ioport.h>
14 #include <linux/interrupt.h>
15 #include <linux/isa.h>
16 #include <linux/kernel.h>
17 #include <linux/list.h>
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/types.h>
21 #include <linux/spinlock.h>
22 
23 #define QUAD8_EXTENT 32
24 
25 static unsigned int base[max_num_isa_dev(QUAD8_EXTENT)];
26 static unsigned int num_quad8;
27 module_param_hw_array(base, uint, ioport, &num_quad8, 0);
28 MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
29 
30 static unsigned int irq[max_num_isa_dev(QUAD8_EXTENT)];
31 module_param_hw_array(irq, uint, irq, NULL, 0);
32 MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
33 
34 #define QUAD8_NUM_COUNTERS 8
35 
36 /**
37  * struct quad8 - device private data structure
38  * @lock:		lock to prevent clobbering device states during R/W ops
39  * @counter:		instance of the counter_device
40  * @fck_prescaler:	array of filter clock prescaler configurations
41  * @preset:		array of preset values
42  * @count_mode:		array of count mode configurations
43  * @quadrature_mode:	array of quadrature mode configurations
44  * @quadrature_scale:	array of quadrature mode scale configurations
45  * @ab_enable:		array of A and B inputs enable configurations
46  * @preset_enable:	array of set_to_preset_on_index attribute configurations
47  * @irq_trigger:	array of current IRQ trigger function configurations
48  * @synchronous_mode:	array of index function synchronous mode configurations
49  * @index_polarity:	array of index function polarity configurations
50  * @cable_fault_enable:	differential encoder cable status enable configurations
51  * @base:		base port address of the device
52  */
53 struct quad8 {
54 	spinlock_t lock;
55 	unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
56 	unsigned int preset[QUAD8_NUM_COUNTERS];
57 	unsigned int count_mode[QUAD8_NUM_COUNTERS];
58 	unsigned int quadrature_mode[QUAD8_NUM_COUNTERS];
59 	unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
60 	unsigned int ab_enable[QUAD8_NUM_COUNTERS];
61 	unsigned int preset_enable[QUAD8_NUM_COUNTERS];
62 	unsigned int irq_trigger[QUAD8_NUM_COUNTERS];
63 	unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
64 	unsigned int index_polarity[QUAD8_NUM_COUNTERS];
65 	unsigned int cable_fault_enable;
66 	unsigned int base;
67 };
68 
69 #define QUAD8_REG_INTERRUPT_STATUS 0x10
70 #define QUAD8_REG_CHAN_OP 0x11
71 #define QUAD8_REG_INDEX_INTERRUPT 0x12
72 #define QUAD8_REG_INDEX_INPUT_LEVELS 0x16
73 #define QUAD8_DIFF_ENCODER_CABLE_STATUS 0x17
74 /* Borrow Toggle flip-flop */
75 #define QUAD8_FLAG_BT BIT(0)
76 /* Carry Toggle flip-flop */
77 #define QUAD8_FLAG_CT BIT(1)
78 /* Error flag */
79 #define QUAD8_FLAG_E BIT(4)
80 /* Up/Down flag */
81 #define QUAD8_FLAG_UD BIT(5)
82 /* Reset and Load Signal Decoders */
83 #define QUAD8_CTR_RLD 0x00
84 /* Counter Mode Register */
85 #define QUAD8_CTR_CMR 0x20
86 /* Input / Output Control Register */
87 #define QUAD8_CTR_IOR 0x40
88 /* Index Control Register */
89 #define QUAD8_CTR_IDR 0x60
90 /* Reset Byte Pointer (three byte data pointer) */
91 #define QUAD8_RLD_RESET_BP 0x01
92 /* Reset Counter */
93 #define QUAD8_RLD_RESET_CNTR 0x02
94 /* Reset Borrow Toggle, Carry Toggle, Compare Toggle, and Sign flags */
95 #define QUAD8_RLD_RESET_FLAGS 0x04
96 /* Reset Error flag */
97 #define QUAD8_RLD_RESET_E 0x06
98 /* Preset Register to Counter */
99 #define QUAD8_RLD_PRESET_CNTR 0x08
100 /* Transfer Counter to Output Latch */
101 #define QUAD8_RLD_CNTR_OUT 0x10
102 /* Transfer Preset Register LSB to FCK Prescaler */
103 #define QUAD8_RLD_PRESET_PSC 0x18
104 #define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
105 #define QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC 0x04
106 #define QUAD8_CMR_QUADRATURE_X1 0x08
107 #define QUAD8_CMR_QUADRATURE_X2 0x10
108 #define QUAD8_CMR_QUADRATURE_X4 0x18
109 
110 static int quad8_signal_read(struct counter_device *counter,
111 			     struct counter_signal *signal,
112 			     enum counter_signal_level *level)
113 {
114 	const struct quad8 *const priv = counter_priv(counter);
115 	unsigned int state;
116 
117 	/* Only Index signal levels can be read */
118 	if (signal->id < 16)
119 		return -EINVAL;
120 
121 	state = inb(priv->base + QUAD8_REG_INDEX_INPUT_LEVELS)
122 		& BIT(signal->id - 16);
123 
124 	*level = (state) ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
125 
126 	return 0;
127 }
128 
129 static int quad8_count_read(struct counter_device *counter,
130 			    struct counter_count *count, u64 *val)
131 {
132 	struct quad8 *const priv = counter_priv(counter);
133 	const int base_offset = priv->base + 2 * count->id;
134 	unsigned int flags;
135 	unsigned int borrow;
136 	unsigned int carry;
137 	unsigned long irqflags;
138 	int i;
139 
140 	flags = inb(base_offset + 1);
141 	borrow = flags & QUAD8_FLAG_BT;
142 	carry = !!(flags & QUAD8_FLAG_CT);
143 
144 	/* Borrow XOR Carry effectively doubles count range */
145 	*val = (unsigned long)(borrow ^ carry) << 24;
146 
147 	spin_lock_irqsave(&priv->lock, irqflags);
148 
149 	/* Reset Byte Pointer; transfer Counter to Output Latch */
150 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
151 	     base_offset + 1);
152 
153 	for (i = 0; i < 3; i++)
154 		*val |= (unsigned long)inb(base_offset) << (8 * i);
155 
156 	spin_unlock_irqrestore(&priv->lock, irqflags);
157 
158 	return 0;
159 }
160 
161 static int quad8_count_write(struct counter_device *counter,
162 			     struct counter_count *count, u64 val)
163 {
164 	struct quad8 *const priv = counter_priv(counter);
165 	const int base_offset = priv->base + 2 * count->id;
166 	unsigned long irqflags;
167 	int i;
168 
169 	/* Only 24-bit values are supported */
170 	if (val > 0xFFFFFF)
171 		return -ERANGE;
172 
173 	spin_lock_irqsave(&priv->lock, irqflags);
174 
175 	/* Reset Byte Pointer */
176 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
177 
178 	/* Counter can only be set via Preset Register */
179 	for (i = 0; i < 3; i++)
180 		outb(val >> (8 * i), base_offset);
181 
182 	/* Transfer Preset Register to Counter */
183 	outb(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, base_offset + 1);
184 
185 	/* Reset Byte Pointer */
186 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
187 
188 	/* Set Preset Register back to original value */
189 	val = priv->preset[count->id];
190 	for (i = 0; i < 3; i++)
191 		outb(val >> (8 * i), base_offset);
192 
193 	/* Reset Borrow, Carry, Compare, and Sign flags */
194 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
195 	/* Reset Error flag */
196 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
197 
198 	spin_unlock_irqrestore(&priv->lock, irqflags);
199 
200 	return 0;
201 }
202 
203 static const enum counter_function quad8_count_functions_list[] = {
204 	COUNTER_FUNCTION_PULSE_DIRECTION,
205 	COUNTER_FUNCTION_QUADRATURE_X1_A,
206 	COUNTER_FUNCTION_QUADRATURE_X2_A,
207 	COUNTER_FUNCTION_QUADRATURE_X4,
208 };
209 
210 static int quad8_function_read(struct counter_device *counter,
211 			       struct counter_count *count,
212 			       enum counter_function *function)
213 {
214 	struct quad8 *const priv = counter_priv(counter);
215 	const int id = count->id;
216 	unsigned long irqflags;
217 
218 	spin_lock_irqsave(&priv->lock, irqflags);
219 
220 	if (priv->quadrature_mode[id])
221 		switch (priv->quadrature_scale[id]) {
222 		case 0:
223 			*function = COUNTER_FUNCTION_QUADRATURE_X1_A;
224 			break;
225 		case 1:
226 			*function = COUNTER_FUNCTION_QUADRATURE_X2_A;
227 			break;
228 		case 2:
229 			*function = COUNTER_FUNCTION_QUADRATURE_X4;
230 			break;
231 		}
232 	else
233 		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
234 
235 	spin_unlock_irqrestore(&priv->lock, irqflags);
236 
237 	return 0;
238 }
239 
240 static int quad8_function_write(struct counter_device *counter,
241 				struct counter_count *count,
242 				enum counter_function function)
243 {
244 	struct quad8 *const priv = counter_priv(counter);
245 	const int id = count->id;
246 	unsigned int *const quadrature_mode = priv->quadrature_mode + id;
247 	unsigned int *const scale = priv->quadrature_scale + id;
248 	unsigned int *const synchronous_mode = priv->synchronous_mode + id;
249 	const int base_offset = priv->base + 2 * id + 1;
250 	unsigned long irqflags;
251 	unsigned int mode_cfg;
252 	unsigned int idr_cfg;
253 
254 	spin_lock_irqsave(&priv->lock, irqflags);
255 
256 	mode_cfg = priv->count_mode[id] << 1;
257 	idr_cfg = priv->index_polarity[id] << 1;
258 
259 	if (function == COUNTER_FUNCTION_PULSE_DIRECTION) {
260 		*quadrature_mode = 0;
261 
262 		/* Quadrature scaling only available in quadrature mode */
263 		*scale = 0;
264 
265 		/* Synchronous function not supported in non-quadrature mode */
266 		if (*synchronous_mode) {
267 			*synchronous_mode = 0;
268 			/* Disable synchronous function mode */
269 			outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
270 		}
271 	} else {
272 		*quadrature_mode = 1;
273 
274 		switch (function) {
275 		case COUNTER_FUNCTION_QUADRATURE_X1_A:
276 			*scale = 0;
277 			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
278 			break;
279 		case COUNTER_FUNCTION_QUADRATURE_X2_A:
280 			*scale = 1;
281 			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
282 			break;
283 		case COUNTER_FUNCTION_QUADRATURE_X4:
284 			*scale = 2;
285 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
286 			break;
287 		default:
288 			/* should never reach this path */
289 			spin_unlock_irqrestore(&priv->lock, irqflags);
290 			return -EINVAL;
291 		}
292 	}
293 
294 	/* Load mode configuration to Counter Mode Register */
295 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
296 
297 	spin_unlock_irqrestore(&priv->lock, irqflags);
298 
299 	return 0;
300 }
301 
302 static int quad8_direction_read(struct counter_device *counter,
303 				struct counter_count *count,
304 				enum counter_count_direction *direction)
305 {
306 	const struct quad8 *const priv = counter_priv(counter);
307 	unsigned int ud_flag;
308 	const unsigned int flag_addr = priv->base + 2 * count->id + 1;
309 
310 	/* U/D flag: nonzero = up, zero = down */
311 	ud_flag = inb(flag_addr) & QUAD8_FLAG_UD;
312 
313 	*direction = (ud_flag) ? COUNTER_COUNT_DIRECTION_FORWARD :
314 		COUNTER_COUNT_DIRECTION_BACKWARD;
315 
316 	return 0;
317 }
318 
319 static const enum counter_synapse_action quad8_index_actions_list[] = {
320 	COUNTER_SYNAPSE_ACTION_NONE,
321 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
322 };
323 
324 static const enum counter_synapse_action quad8_synapse_actions_list[] = {
325 	COUNTER_SYNAPSE_ACTION_NONE,
326 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
327 	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
328 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
329 };
330 
331 static int quad8_action_read(struct counter_device *counter,
332 			     struct counter_count *count,
333 			     struct counter_synapse *synapse,
334 			     enum counter_synapse_action *action)
335 {
336 	struct quad8 *const priv = counter_priv(counter);
337 	int err;
338 	enum counter_function function;
339 	const size_t signal_a_id = count->synapses[0].signal->id;
340 	enum counter_count_direction direction;
341 
342 	/* Handle Index signals */
343 	if (synapse->signal->id >= 16) {
344 		if (priv->preset_enable[count->id])
345 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
346 		else
347 			*action = COUNTER_SYNAPSE_ACTION_NONE;
348 
349 		return 0;
350 	}
351 
352 	err = quad8_function_read(counter, count, &function);
353 	if (err)
354 		return err;
355 
356 	/* Default action mode */
357 	*action = COUNTER_SYNAPSE_ACTION_NONE;
358 
359 	/* Determine action mode based on current count function mode */
360 	switch (function) {
361 	case COUNTER_FUNCTION_PULSE_DIRECTION:
362 		if (synapse->signal->id == signal_a_id)
363 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
364 		return 0;
365 	case COUNTER_FUNCTION_QUADRATURE_X1_A:
366 		if (synapse->signal->id == signal_a_id) {
367 			err = quad8_direction_read(counter, count, &direction);
368 			if (err)
369 				return err;
370 
371 			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
372 				*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
373 			else
374 				*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
375 		}
376 		return 0;
377 	case COUNTER_FUNCTION_QUADRATURE_X2_A:
378 		if (synapse->signal->id == signal_a_id)
379 			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
380 		return 0;
381 	case COUNTER_FUNCTION_QUADRATURE_X4:
382 		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
383 		return 0;
384 	default:
385 		/* should never reach this path */
386 		return -EINVAL;
387 	}
388 }
389 
390 enum {
391 	QUAD8_EVENT_CARRY = 0,
392 	QUAD8_EVENT_COMPARE = 1,
393 	QUAD8_EVENT_CARRY_BORROW = 2,
394 	QUAD8_EVENT_INDEX = 3,
395 };
396 
397 static int quad8_events_configure(struct counter_device *counter)
398 {
399 	struct quad8 *const priv = counter_priv(counter);
400 	unsigned long irq_enabled = 0;
401 	unsigned long irqflags;
402 	struct counter_event_node *event_node;
403 	unsigned int next_irq_trigger;
404 	unsigned long ior_cfg;
405 	unsigned long base_offset;
406 
407 	spin_lock_irqsave(&priv->lock, irqflags);
408 
409 	list_for_each_entry(event_node, &counter->events_list, l) {
410 		switch (event_node->event) {
411 		case COUNTER_EVENT_OVERFLOW:
412 			next_irq_trigger = QUAD8_EVENT_CARRY;
413 			break;
414 		case COUNTER_EVENT_THRESHOLD:
415 			next_irq_trigger = QUAD8_EVENT_COMPARE;
416 			break;
417 		case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
418 			next_irq_trigger = QUAD8_EVENT_CARRY_BORROW;
419 			break;
420 		case COUNTER_EVENT_INDEX:
421 			next_irq_trigger = QUAD8_EVENT_INDEX;
422 			break;
423 		default:
424 			/* should never reach this path */
425 			spin_unlock_irqrestore(&priv->lock, irqflags);
426 			return -EINVAL;
427 		}
428 
429 		/* Skip configuration if it is the same as previously set */
430 		if (priv->irq_trigger[event_node->channel] == next_irq_trigger)
431 			continue;
432 
433 		/* Save new IRQ function configuration */
434 		priv->irq_trigger[event_node->channel] = next_irq_trigger;
435 
436 		/* Load configuration to I/O Control Register */
437 		ior_cfg = priv->ab_enable[event_node->channel] |
438 			  priv->preset_enable[event_node->channel] << 1 |
439 			  priv->irq_trigger[event_node->channel] << 3;
440 		base_offset = priv->base + 2 * event_node->channel + 1;
441 		outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
442 
443 		/* Enable IRQ line */
444 		irq_enabled |= BIT(event_node->channel);
445 	}
446 
447 	outb(irq_enabled, priv->base + QUAD8_REG_INDEX_INTERRUPT);
448 
449 	spin_unlock_irqrestore(&priv->lock, irqflags);
450 
451 	return 0;
452 }
453 
454 static int quad8_watch_validate(struct counter_device *counter,
455 				const struct counter_watch *watch)
456 {
457 	struct counter_event_node *event_node;
458 
459 	if (watch->channel > QUAD8_NUM_COUNTERS - 1)
460 		return -EINVAL;
461 
462 	switch (watch->event) {
463 	case COUNTER_EVENT_OVERFLOW:
464 	case COUNTER_EVENT_THRESHOLD:
465 	case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
466 	case COUNTER_EVENT_INDEX:
467 		list_for_each_entry(event_node, &counter->next_events_list, l)
468 			if (watch->channel == event_node->channel &&
469 				watch->event != event_node->event)
470 				return -EINVAL;
471 		return 0;
472 	default:
473 		return -EINVAL;
474 	}
475 }
476 
477 static const struct counter_ops quad8_ops = {
478 	.signal_read = quad8_signal_read,
479 	.count_read = quad8_count_read,
480 	.count_write = quad8_count_write,
481 	.function_read = quad8_function_read,
482 	.function_write = quad8_function_write,
483 	.action_read = quad8_action_read,
484 	.events_configure = quad8_events_configure,
485 	.watch_validate = quad8_watch_validate,
486 };
487 
488 static const char *const quad8_index_polarity_modes[] = {
489 	"negative",
490 	"positive"
491 };
492 
493 static int quad8_index_polarity_get(struct counter_device *counter,
494 				    struct counter_signal *signal,
495 				    u32 *index_polarity)
496 {
497 	const struct quad8 *const priv = counter_priv(counter);
498 	const size_t channel_id = signal->id - 16;
499 
500 	*index_polarity = priv->index_polarity[channel_id];
501 
502 	return 0;
503 }
504 
505 static int quad8_index_polarity_set(struct counter_device *counter,
506 				    struct counter_signal *signal,
507 				    u32 index_polarity)
508 {
509 	struct quad8 *const priv = counter_priv(counter);
510 	const size_t channel_id = signal->id - 16;
511 	const int base_offset = priv->base + 2 * channel_id + 1;
512 	unsigned long irqflags;
513 	unsigned int idr_cfg = index_polarity << 1;
514 
515 	spin_lock_irqsave(&priv->lock, irqflags);
516 
517 	idr_cfg |= priv->synchronous_mode[channel_id];
518 
519 	priv->index_polarity[channel_id] = index_polarity;
520 
521 	/* Load Index Control configuration to Index Control Register */
522 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
523 
524 	spin_unlock_irqrestore(&priv->lock, irqflags);
525 
526 	return 0;
527 }
528 
529 static const char *const quad8_synchronous_modes[] = {
530 	"non-synchronous",
531 	"synchronous"
532 };
533 
534 static int quad8_synchronous_mode_get(struct counter_device *counter,
535 				      struct counter_signal *signal,
536 				      u32 *synchronous_mode)
537 {
538 	const struct quad8 *const priv = counter_priv(counter);
539 	const size_t channel_id = signal->id - 16;
540 
541 	*synchronous_mode = priv->synchronous_mode[channel_id];
542 
543 	return 0;
544 }
545 
546 static int quad8_synchronous_mode_set(struct counter_device *counter,
547 				      struct counter_signal *signal,
548 				      u32 synchronous_mode)
549 {
550 	struct quad8 *const priv = counter_priv(counter);
551 	const size_t channel_id = signal->id - 16;
552 	const int base_offset = priv->base + 2 * channel_id + 1;
553 	unsigned long irqflags;
554 	unsigned int idr_cfg = synchronous_mode;
555 
556 	spin_lock_irqsave(&priv->lock, irqflags);
557 
558 	idr_cfg |= priv->index_polarity[channel_id] << 1;
559 
560 	/* Index function must be non-synchronous in non-quadrature mode */
561 	if (synchronous_mode && !priv->quadrature_mode[channel_id]) {
562 		spin_unlock_irqrestore(&priv->lock, irqflags);
563 		return -EINVAL;
564 	}
565 
566 	priv->synchronous_mode[channel_id] = synchronous_mode;
567 
568 	/* Load Index Control configuration to Index Control Register */
569 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
570 
571 	spin_unlock_irqrestore(&priv->lock, irqflags);
572 
573 	return 0;
574 }
575 
576 static int quad8_count_floor_read(struct counter_device *counter,
577 				  struct counter_count *count, u64 *floor)
578 {
579 	/* Only a floor of 0 is supported */
580 	*floor = 0;
581 
582 	return 0;
583 }
584 
585 static int quad8_count_mode_read(struct counter_device *counter,
586 				 struct counter_count *count,
587 				 enum counter_count_mode *cnt_mode)
588 {
589 	const struct quad8 *const priv = counter_priv(counter);
590 
591 	/* Map 104-QUAD-8 count mode to Generic Counter count mode */
592 	switch (priv->count_mode[count->id]) {
593 	case 0:
594 		*cnt_mode = COUNTER_COUNT_MODE_NORMAL;
595 		break;
596 	case 1:
597 		*cnt_mode = COUNTER_COUNT_MODE_RANGE_LIMIT;
598 		break;
599 	case 2:
600 		*cnt_mode = COUNTER_COUNT_MODE_NON_RECYCLE;
601 		break;
602 	case 3:
603 		*cnt_mode = COUNTER_COUNT_MODE_MODULO_N;
604 		break;
605 	}
606 
607 	return 0;
608 }
609 
610 static int quad8_count_mode_write(struct counter_device *counter,
611 				  struct counter_count *count,
612 				  enum counter_count_mode cnt_mode)
613 {
614 	struct quad8 *const priv = counter_priv(counter);
615 	unsigned int count_mode;
616 	unsigned int mode_cfg;
617 	const int base_offset = priv->base + 2 * count->id + 1;
618 	unsigned long irqflags;
619 
620 	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
621 	switch (cnt_mode) {
622 	case COUNTER_COUNT_MODE_NORMAL:
623 		count_mode = 0;
624 		break;
625 	case COUNTER_COUNT_MODE_RANGE_LIMIT:
626 		count_mode = 1;
627 		break;
628 	case COUNTER_COUNT_MODE_NON_RECYCLE:
629 		count_mode = 2;
630 		break;
631 	case COUNTER_COUNT_MODE_MODULO_N:
632 		count_mode = 3;
633 		break;
634 	default:
635 		/* should never reach this path */
636 		return -EINVAL;
637 	}
638 
639 	spin_lock_irqsave(&priv->lock, irqflags);
640 
641 	priv->count_mode[count->id] = count_mode;
642 
643 	/* Set count mode configuration value */
644 	mode_cfg = count_mode << 1;
645 
646 	/* Add quadrature mode configuration */
647 	if (priv->quadrature_mode[count->id])
648 		mode_cfg |= (priv->quadrature_scale[count->id] + 1) << 3;
649 
650 	/* Load mode configuration to Counter Mode Register */
651 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
652 
653 	spin_unlock_irqrestore(&priv->lock, irqflags);
654 
655 	return 0;
656 }
657 
658 static int quad8_count_enable_read(struct counter_device *counter,
659 				   struct counter_count *count, u8 *enable)
660 {
661 	const struct quad8 *const priv = counter_priv(counter);
662 
663 	*enable = priv->ab_enable[count->id];
664 
665 	return 0;
666 }
667 
668 static int quad8_count_enable_write(struct counter_device *counter,
669 				    struct counter_count *count, u8 enable)
670 {
671 	struct quad8 *const priv = counter_priv(counter);
672 	const int base_offset = priv->base + 2 * count->id;
673 	unsigned long irqflags;
674 	unsigned int ior_cfg;
675 
676 	spin_lock_irqsave(&priv->lock, irqflags);
677 
678 	priv->ab_enable[count->id] = enable;
679 
680 	ior_cfg = enable | priv->preset_enable[count->id] << 1 |
681 		  priv->irq_trigger[count->id] << 3;
682 
683 	/* Load I/O control configuration */
684 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
685 
686 	spin_unlock_irqrestore(&priv->lock, irqflags);
687 
688 	return 0;
689 }
690 
691 static const char *const quad8_noise_error_states[] = {
692 	"No excessive noise is present at the count inputs",
693 	"Excessive noise is present at the count inputs"
694 };
695 
696 static int quad8_error_noise_get(struct counter_device *counter,
697 				 struct counter_count *count, u32 *noise_error)
698 {
699 	const struct quad8 *const priv = counter_priv(counter);
700 	const int base_offset = priv->base + 2 * count->id + 1;
701 
702 	*noise_error = !!(inb(base_offset) & QUAD8_FLAG_E);
703 
704 	return 0;
705 }
706 
707 static int quad8_count_preset_read(struct counter_device *counter,
708 				   struct counter_count *count, u64 *preset)
709 {
710 	const struct quad8 *const priv = counter_priv(counter);
711 
712 	*preset = priv->preset[count->id];
713 
714 	return 0;
715 }
716 
717 static void quad8_preset_register_set(struct quad8 *const priv, const int id,
718 				      const unsigned int preset)
719 {
720 	const unsigned int base_offset = priv->base + 2 * id;
721 	int i;
722 
723 	priv->preset[id] = preset;
724 
725 	/* Reset Byte Pointer */
726 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
727 
728 	/* Set Preset Register */
729 	for (i = 0; i < 3; i++)
730 		outb(preset >> (8 * i), base_offset);
731 }
732 
733 static int quad8_count_preset_write(struct counter_device *counter,
734 				    struct counter_count *count, u64 preset)
735 {
736 	struct quad8 *const priv = counter_priv(counter);
737 	unsigned long irqflags;
738 
739 	/* Only 24-bit values are supported */
740 	if (preset > 0xFFFFFF)
741 		return -ERANGE;
742 
743 	spin_lock_irqsave(&priv->lock, irqflags);
744 
745 	quad8_preset_register_set(priv, count->id, preset);
746 
747 	spin_unlock_irqrestore(&priv->lock, irqflags);
748 
749 	return 0;
750 }
751 
752 static int quad8_count_ceiling_read(struct counter_device *counter,
753 				    struct counter_count *count, u64 *ceiling)
754 {
755 	struct quad8 *const priv = counter_priv(counter);
756 	unsigned long irqflags;
757 
758 	spin_lock_irqsave(&priv->lock, irqflags);
759 
760 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
761 	switch (priv->count_mode[count->id]) {
762 	case 1:
763 	case 3:
764 		*ceiling = priv->preset[count->id];
765 		break;
766 	default:
767 		/* By default 0x1FFFFFF (25 bits unsigned) is maximum count */
768 		*ceiling = 0x1FFFFFF;
769 		break;
770 	}
771 
772 	spin_unlock_irqrestore(&priv->lock, irqflags);
773 
774 	return 0;
775 }
776 
777 static int quad8_count_ceiling_write(struct counter_device *counter,
778 				     struct counter_count *count, u64 ceiling)
779 {
780 	struct quad8 *const priv = counter_priv(counter);
781 	unsigned long irqflags;
782 
783 	/* Only 24-bit values are supported */
784 	if (ceiling > 0xFFFFFF)
785 		return -ERANGE;
786 
787 	spin_lock_irqsave(&priv->lock, irqflags);
788 
789 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
790 	switch (priv->count_mode[count->id]) {
791 	case 1:
792 	case 3:
793 		quad8_preset_register_set(priv, count->id, ceiling);
794 		spin_unlock_irqrestore(&priv->lock, irqflags);
795 		return 0;
796 	}
797 
798 	spin_unlock_irqrestore(&priv->lock, irqflags);
799 
800 	return -EINVAL;
801 }
802 
803 static int quad8_count_preset_enable_read(struct counter_device *counter,
804 					  struct counter_count *count,
805 					  u8 *preset_enable)
806 {
807 	const struct quad8 *const priv = counter_priv(counter);
808 
809 	*preset_enable = !priv->preset_enable[count->id];
810 
811 	return 0;
812 }
813 
814 static int quad8_count_preset_enable_write(struct counter_device *counter,
815 					   struct counter_count *count,
816 					   u8 preset_enable)
817 {
818 	struct quad8 *const priv = counter_priv(counter);
819 	const int base_offset = priv->base + 2 * count->id + 1;
820 	unsigned long irqflags;
821 	unsigned int ior_cfg;
822 
823 	/* Preset enable is active low in Input/Output Control register */
824 	preset_enable = !preset_enable;
825 
826 	spin_lock_irqsave(&priv->lock, irqflags);
827 
828 	priv->preset_enable[count->id] = preset_enable;
829 
830 	ior_cfg = priv->ab_enable[count->id] | preset_enable << 1 |
831 		  priv->irq_trigger[count->id] << 3;
832 
833 	/* Load I/O control configuration to Input / Output Control Register */
834 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
835 
836 	spin_unlock_irqrestore(&priv->lock, irqflags);
837 
838 	return 0;
839 }
840 
841 static int quad8_signal_cable_fault_read(struct counter_device *counter,
842 					 struct counter_signal *signal,
843 					 u8 *cable_fault)
844 {
845 	struct quad8 *const priv = counter_priv(counter);
846 	const size_t channel_id = signal->id / 2;
847 	unsigned long irqflags;
848 	bool disabled;
849 	unsigned int status;
850 
851 	spin_lock_irqsave(&priv->lock, irqflags);
852 
853 	disabled = !(priv->cable_fault_enable & BIT(channel_id));
854 
855 	if (disabled) {
856 		spin_unlock_irqrestore(&priv->lock, irqflags);
857 		return -EINVAL;
858 	}
859 
860 	/* Logic 0 = cable fault */
861 	status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
862 
863 	spin_unlock_irqrestore(&priv->lock, irqflags);
864 
865 	/* Mask respective channel and invert logic */
866 	*cable_fault = !(status & BIT(channel_id));
867 
868 	return 0;
869 }
870 
871 static int quad8_signal_cable_fault_enable_read(struct counter_device *counter,
872 						struct counter_signal *signal,
873 						u8 *enable)
874 {
875 	const struct quad8 *const priv = counter_priv(counter);
876 	const size_t channel_id = signal->id / 2;
877 
878 	*enable = !!(priv->cable_fault_enable & BIT(channel_id));
879 
880 	return 0;
881 }
882 
883 static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
884 						 struct counter_signal *signal,
885 						 u8 enable)
886 {
887 	struct quad8 *const priv = counter_priv(counter);
888 	const size_t channel_id = signal->id / 2;
889 	unsigned long irqflags;
890 	unsigned int cable_fault_enable;
891 
892 	spin_lock_irqsave(&priv->lock, irqflags);
893 
894 	if (enable)
895 		priv->cable_fault_enable |= BIT(channel_id);
896 	else
897 		priv->cable_fault_enable &= ~BIT(channel_id);
898 
899 	/* Enable is active low in Differential Encoder Cable Status register */
900 	cable_fault_enable = ~priv->cable_fault_enable;
901 
902 	outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
903 
904 	spin_unlock_irqrestore(&priv->lock, irqflags);
905 
906 	return 0;
907 }
908 
909 static int quad8_signal_fck_prescaler_read(struct counter_device *counter,
910 					   struct counter_signal *signal,
911 					   u8 *prescaler)
912 {
913 	const struct quad8 *const priv = counter_priv(counter);
914 
915 	*prescaler = priv->fck_prescaler[signal->id / 2];
916 
917 	return 0;
918 }
919 
920 static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
921 					    struct counter_signal *signal,
922 					    u8 prescaler)
923 {
924 	struct quad8 *const priv = counter_priv(counter);
925 	const size_t channel_id = signal->id / 2;
926 	const int base_offset = priv->base + 2 * channel_id;
927 	unsigned long irqflags;
928 
929 	spin_lock_irqsave(&priv->lock, irqflags);
930 
931 	priv->fck_prescaler[channel_id] = prescaler;
932 
933 	/* Reset Byte Pointer */
934 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
935 
936 	/* Set filter clock factor */
937 	outb(prescaler, base_offset);
938 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
939 	     base_offset + 1);
940 
941 	spin_unlock_irqrestore(&priv->lock, irqflags);
942 
943 	return 0;
944 }
945 
946 static struct counter_comp quad8_signal_ext[] = {
947 	COUNTER_COMP_SIGNAL_BOOL("cable_fault", quad8_signal_cable_fault_read,
948 				 NULL),
949 	COUNTER_COMP_SIGNAL_BOOL("cable_fault_enable",
950 				 quad8_signal_cable_fault_enable_read,
951 				 quad8_signal_cable_fault_enable_write),
952 	COUNTER_COMP_SIGNAL_U8("filter_clock_prescaler",
953 			       quad8_signal_fck_prescaler_read,
954 			       quad8_signal_fck_prescaler_write)
955 };
956 
957 static DEFINE_COUNTER_ENUM(quad8_index_pol_enum, quad8_index_polarity_modes);
958 static DEFINE_COUNTER_ENUM(quad8_synch_mode_enum, quad8_synchronous_modes);
959 
960 static struct counter_comp quad8_index_ext[] = {
961 	COUNTER_COMP_SIGNAL_ENUM("index_polarity", quad8_index_polarity_get,
962 				 quad8_index_polarity_set,
963 				 quad8_index_pol_enum),
964 	COUNTER_COMP_SIGNAL_ENUM("synchronous_mode", quad8_synchronous_mode_get,
965 				 quad8_synchronous_mode_set,
966 				 quad8_synch_mode_enum),
967 };
968 
969 #define QUAD8_QUAD_SIGNAL(_id, _name) {		\
970 	.id = (_id),				\
971 	.name = (_name),			\
972 	.ext = quad8_signal_ext,		\
973 	.num_ext = ARRAY_SIZE(quad8_signal_ext)	\
974 }
975 
976 #define	QUAD8_INDEX_SIGNAL(_id, _name) {	\
977 	.id = (_id),				\
978 	.name = (_name),			\
979 	.ext = quad8_index_ext,			\
980 	.num_ext = ARRAY_SIZE(quad8_index_ext)	\
981 }
982 
983 static struct counter_signal quad8_signals[] = {
984 	QUAD8_QUAD_SIGNAL(0, "Channel 1 Quadrature A"),
985 	QUAD8_QUAD_SIGNAL(1, "Channel 1 Quadrature B"),
986 	QUAD8_QUAD_SIGNAL(2, "Channel 2 Quadrature A"),
987 	QUAD8_QUAD_SIGNAL(3, "Channel 2 Quadrature B"),
988 	QUAD8_QUAD_SIGNAL(4, "Channel 3 Quadrature A"),
989 	QUAD8_QUAD_SIGNAL(5, "Channel 3 Quadrature B"),
990 	QUAD8_QUAD_SIGNAL(6, "Channel 4 Quadrature A"),
991 	QUAD8_QUAD_SIGNAL(7, "Channel 4 Quadrature B"),
992 	QUAD8_QUAD_SIGNAL(8, "Channel 5 Quadrature A"),
993 	QUAD8_QUAD_SIGNAL(9, "Channel 5 Quadrature B"),
994 	QUAD8_QUAD_SIGNAL(10, "Channel 6 Quadrature A"),
995 	QUAD8_QUAD_SIGNAL(11, "Channel 6 Quadrature B"),
996 	QUAD8_QUAD_SIGNAL(12, "Channel 7 Quadrature A"),
997 	QUAD8_QUAD_SIGNAL(13, "Channel 7 Quadrature B"),
998 	QUAD8_QUAD_SIGNAL(14, "Channel 8 Quadrature A"),
999 	QUAD8_QUAD_SIGNAL(15, "Channel 8 Quadrature B"),
1000 	QUAD8_INDEX_SIGNAL(16, "Channel 1 Index"),
1001 	QUAD8_INDEX_SIGNAL(17, "Channel 2 Index"),
1002 	QUAD8_INDEX_SIGNAL(18, "Channel 3 Index"),
1003 	QUAD8_INDEX_SIGNAL(19, "Channel 4 Index"),
1004 	QUAD8_INDEX_SIGNAL(20, "Channel 5 Index"),
1005 	QUAD8_INDEX_SIGNAL(21, "Channel 6 Index"),
1006 	QUAD8_INDEX_SIGNAL(22, "Channel 7 Index"),
1007 	QUAD8_INDEX_SIGNAL(23, "Channel 8 Index")
1008 };
1009 
1010 #define QUAD8_COUNT_SYNAPSES(_id) {					\
1011 	{								\
1012 		.actions_list = quad8_synapse_actions_list,		\
1013 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1014 		.signal = quad8_signals + 2 * (_id)			\
1015 	},								\
1016 	{								\
1017 		.actions_list = quad8_synapse_actions_list,		\
1018 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1019 		.signal = quad8_signals + 2 * (_id) + 1			\
1020 	},								\
1021 	{								\
1022 		.actions_list = quad8_index_actions_list,		\
1023 		.num_actions = ARRAY_SIZE(quad8_index_actions_list),	\
1024 		.signal = quad8_signals + 2 * (_id) + 16		\
1025 	}								\
1026 }
1027 
1028 static struct counter_synapse quad8_count_synapses[][3] = {
1029 	QUAD8_COUNT_SYNAPSES(0), QUAD8_COUNT_SYNAPSES(1),
1030 	QUAD8_COUNT_SYNAPSES(2), QUAD8_COUNT_SYNAPSES(3),
1031 	QUAD8_COUNT_SYNAPSES(4), QUAD8_COUNT_SYNAPSES(5),
1032 	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
1033 };
1034 
1035 static const enum counter_count_mode quad8_cnt_modes[] = {
1036 	COUNTER_COUNT_MODE_NORMAL,
1037 	COUNTER_COUNT_MODE_RANGE_LIMIT,
1038 	COUNTER_COUNT_MODE_NON_RECYCLE,
1039 	COUNTER_COUNT_MODE_MODULO_N,
1040 };
1041 
1042 static DEFINE_COUNTER_AVAILABLE(quad8_count_mode_available, quad8_cnt_modes);
1043 
1044 static DEFINE_COUNTER_ENUM(quad8_error_noise_enum, quad8_noise_error_states);
1045 
1046 static struct counter_comp quad8_count_ext[] = {
1047 	COUNTER_COMP_CEILING(quad8_count_ceiling_read,
1048 			     quad8_count_ceiling_write),
1049 	COUNTER_COMP_FLOOR(quad8_count_floor_read, NULL),
1050 	COUNTER_COMP_COUNT_MODE(quad8_count_mode_read, quad8_count_mode_write,
1051 				quad8_count_mode_available),
1052 	COUNTER_COMP_DIRECTION(quad8_direction_read),
1053 	COUNTER_COMP_ENABLE(quad8_count_enable_read, quad8_count_enable_write),
1054 	COUNTER_COMP_COUNT_ENUM("error_noise", quad8_error_noise_get, NULL,
1055 				quad8_error_noise_enum),
1056 	COUNTER_COMP_PRESET(quad8_count_preset_read, quad8_count_preset_write),
1057 	COUNTER_COMP_PRESET_ENABLE(quad8_count_preset_enable_read,
1058 				   quad8_count_preset_enable_write),
1059 };
1060 
1061 #define QUAD8_COUNT(_id, _cntname) {					\
1062 	.id = (_id),							\
1063 	.name = (_cntname),						\
1064 	.functions_list = quad8_count_functions_list,			\
1065 	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
1066 	.synapses = quad8_count_synapses[(_id)],			\
1067 	.num_synapses =	2,						\
1068 	.ext = quad8_count_ext,						\
1069 	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
1070 }
1071 
1072 static struct counter_count quad8_counts[] = {
1073 	QUAD8_COUNT(0, "Channel 1 Count"),
1074 	QUAD8_COUNT(1, "Channel 2 Count"),
1075 	QUAD8_COUNT(2, "Channel 3 Count"),
1076 	QUAD8_COUNT(3, "Channel 4 Count"),
1077 	QUAD8_COUNT(4, "Channel 5 Count"),
1078 	QUAD8_COUNT(5, "Channel 6 Count"),
1079 	QUAD8_COUNT(6, "Channel 7 Count"),
1080 	QUAD8_COUNT(7, "Channel 8 Count")
1081 };
1082 
1083 static irqreturn_t quad8_irq_handler(int irq, void *private)
1084 {
1085 	struct counter_device *counter = private;
1086 	struct quad8 *const priv = counter_priv(counter);
1087 	const unsigned long base = priv->base;
1088 	unsigned long irq_status;
1089 	unsigned long channel;
1090 	u8 event;
1091 
1092 	irq_status = inb(base + QUAD8_REG_INTERRUPT_STATUS);
1093 	if (!irq_status)
1094 		return IRQ_NONE;
1095 
1096 	for_each_set_bit(channel, &irq_status, QUAD8_NUM_COUNTERS) {
1097 		switch (priv->irq_trigger[channel]) {
1098 		case QUAD8_EVENT_CARRY:
1099 			event = COUNTER_EVENT_OVERFLOW;
1100 				break;
1101 		case QUAD8_EVENT_COMPARE:
1102 			event = COUNTER_EVENT_THRESHOLD;
1103 				break;
1104 		case QUAD8_EVENT_CARRY_BORROW:
1105 			event = COUNTER_EVENT_OVERFLOW_UNDERFLOW;
1106 				break;
1107 		case QUAD8_EVENT_INDEX:
1108 			event = COUNTER_EVENT_INDEX;
1109 				break;
1110 		default:
1111 			/* should never reach this path */
1112 			WARN_ONCE(true, "invalid interrupt trigger function %u configured for channel %lu\n",
1113 				  priv->irq_trigger[channel], channel);
1114 			continue;
1115 		}
1116 
1117 		counter_push_event(counter, event, channel);
1118 	}
1119 
1120 	/* Clear pending interrupts on device */
1121 	outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base + QUAD8_REG_CHAN_OP);
1122 
1123 	return IRQ_HANDLED;
1124 }
1125 
1126 static int quad8_probe(struct device *dev, unsigned int id)
1127 {
1128 	struct counter_device *counter;
1129 	struct quad8 *priv;
1130 	int i, j;
1131 	unsigned int base_offset;
1132 	int err;
1133 
1134 	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
1135 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
1136 			base[id], base[id] + QUAD8_EXTENT);
1137 		return -EBUSY;
1138 	}
1139 
1140 	counter = devm_counter_alloc(dev, sizeof(*priv));
1141 	if (!counter)
1142 		return -ENOMEM;
1143 	priv = counter_priv(counter);
1144 
1145 	/* Initialize Counter device and driver data */
1146 	counter->name = dev_name(dev);
1147 	counter->parent = dev;
1148 	counter->ops = &quad8_ops;
1149 	counter->counts = quad8_counts;
1150 	counter->num_counts = ARRAY_SIZE(quad8_counts);
1151 	counter->signals = quad8_signals;
1152 	counter->num_signals = ARRAY_SIZE(quad8_signals);
1153 	priv->base = base[id];
1154 
1155 	spin_lock_init(&priv->lock);
1156 
1157 	/* Reset Index/Interrupt Register */
1158 	outb(0x00, base[id] + QUAD8_REG_INDEX_INTERRUPT);
1159 	/* Reset all counters and disable interrupt function */
1160 	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
1161 	/* Set initial configuration for all counters */
1162 	for (i = 0; i < QUAD8_NUM_COUNTERS; i++) {
1163 		base_offset = base[id] + 2 * i;
1164 		/* Reset Byte Pointer */
1165 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
1166 		/* Reset filter clock factor */
1167 		outb(0, base_offset);
1168 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
1169 		     base_offset + 1);
1170 		/* Reset Byte Pointer */
1171 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
1172 		/* Reset Preset Register */
1173 		for (j = 0; j < 3; j++)
1174 			outb(0x00, base_offset);
1175 		/* Reset Borrow, Carry, Compare, and Sign flags */
1176 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
1177 		/* Reset Error flag */
1178 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
1179 		/* Binary encoding; Normal count; non-quadrature mode */
1180 		outb(QUAD8_CTR_CMR, base_offset + 1);
1181 		/* Disable A and B inputs; preset on index; FLG1 as Carry */
1182 		outb(QUAD8_CTR_IOR, base_offset + 1);
1183 		/* Disable index function; negative index polarity */
1184 		outb(QUAD8_CTR_IDR, base_offset + 1);
1185 	}
1186 	/* Disable Differential Encoder Cable Status for all channels */
1187 	outb(0xFF, base[id] + QUAD8_DIFF_ENCODER_CABLE_STATUS);
1188 	/* Enable all counters and enable interrupt function */
1189 	outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base[id] + QUAD8_REG_CHAN_OP);
1190 
1191 	err = devm_request_irq(&counter->dev, irq[id], quad8_irq_handler,
1192 			       IRQF_SHARED, counter->name, counter);
1193 	if (err)
1194 		return err;
1195 
1196 	err = devm_counter_add(dev, counter);
1197 	if (err < 0)
1198 		return dev_err_probe(dev, err, "Failed to add counter\n");
1199 
1200 	return 0;
1201 }
1202 
1203 static struct isa_driver quad8_driver = {
1204 	.probe = quad8_probe,
1205 	.driver = {
1206 		.name = "104-quad-8"
1207 	}
1208 };
1209 
1210 module_isa_driver(quad8_driver, num_quad8);
1211 
1212 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
1213 MODULE_DESCRIPTION("ACCES 104-QUAD-8 driver");
1214 MODULE_LICENSE("GPL v2");
1215