xref: /linux/drivers/counter/104-quad-8.c (revision f055268e3946555deb9bb80b2c8c9798c64dbc47)
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 channel_reg - channel register structure
38  * @data:	Count data
39  * @control:	Channel flags and control
40  */
41 struct channel_reg {
42 	u8 data;
43 	u8 control;
44 };
45 
46 /**
47  * struct quad8_reg - device register structure
48  * @channel:		quadrature counter data and control
49  * @interrupt_status:	channel interrupt status
50  * @channel_oper:	enable/reset counters and interrupt functions
51  * @index_interrupt:	enable channel interrupts
52  * @reserved:		reserved for Factory Use
53  * @index_input_levels:	index signal logical input level
54  * @cable_status:	differential encoder cable status
55  */
56 struct quad8_reg {
57 	struct channel_reg channel[QUAD8_NUM_COUNTERS];
58 	u8 interrupt_status;
59 	u8 channel_oper;
60 	u8 index_interrupt;
61 	u8 reserved[3];
62 	u8 index_input_levels;
63 	u8 cable_status;
64 };
65 
66 /**
67  * struct quad8 - device private data structure
68  * @lock:		lock to prevent clobbering device states during R/W ops
69  * @counter:		instance of the counter_device
70  * @fck_prescaler:	array of filter clock prescaler configurations
71  * @preset:		array of preset values
72  * @count_mode:		array of count mode configurations
73  * @quadrature_mode:	array of quadrature mode configurations
74  * @quadrature_scale:	array of quadrature mode scale configurations
75  * @ab_enable:		array of A and B inputs enable configurations
76  * @preset_enable:	array of set_to_preset_on_index attribute configurations
77  * @irq_trigger:	array of current IRQ trigger function configurations
78  * @synchronous_mode:	array of index function synchronous mode configurations
79  * @index_polarity:	array of index function polarity configurations
80  * @cable_fault_enable:	differential encoder cable status enable configurations
81  * @reg:		I/O address offset for the device registers
82  */
83 struct quad8 {
84 	spinlock_t lock;
85 	unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
86 	unsigned int preset[QUAD8_NUM_COUNTERS];
87 	unsigned int count_mode[QUAD8_NUM_COUNTERS];
88 	unsigned int quadrature_mode[QUAD8_NUM_COUNTERS];
89 	unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
90 	unsigned int ab_enable[QUAD8_NUM_COUNTERS];
91 	unsigned int preset_enable[QUAD8_NUM_COUNTERS];
92 	unsigned int irq_trigger[QUAD8_NUM_COUNTERS];
93 	unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
94 	unsigned int index_polarity[QUAD8_NUM_COUNTERS];
95 	unsigned int cable_fault_enable;
96 	struct quad8_reg __iomem *reg;
97 };
98 
99 /* Borrow Toggle flip-flop */
100 #define QUAD8_FLAG_BT BIT(0)
101 /* Carry Toggle flip-flop */
102 #define QUAD8_FLAG_CT BIT(1)
103 /* Error flag */
104 #define QUAD8_FLAG_E BIT(4)
105 /* Up/Down flag */
106 #define QUAD8_FLAG_UD BIT(5)
107 /* Reset and Load Signal Decoders */
108 #define QUAD8_CTR_RLD 0x00
109 /* Counter Mode Register */
110 #define QUAD8_CTR_CMR 0x20
111 /* Input / Output Control Register */
112 #define QUAD8_CTR_IOR 0x40
113 /* Index Control Register */
114 #define QUAD8_CTR_IDR 0x60
115 /* Reset Byte Pointer (three byte data pointer) */
116 #define QUAD8_RLD_RESET_BP 0x01
117 /* Reset Counter */
118 #define QUAD8_RLD_RESET_CNTR 0x02
119 /* Reset Borrow Toggle, Carry Toggle, Compare Toggle, and Sign flags */
120 #define QUAD8_RLD_RESET_FLAGS 0x04
121 /* Reset Error flag */
122 #define QUAD8_RLD_RESET_E 0x06
123 /* Preset Register to Counter */
124 #define QUAD8_RLD_PRESET_CNTR 0x08
125 /* Transfer Counter to Output Latch */
126 #define QUAD8_RLD_CNTR_OUT 0x10
127 /* Transfer Preset Register LSB to FCK Prescaler */
128 #define QUAD8_RLD_PRESET_PSC 0x18
129 #define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
130 #define QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC 0x04
131 #define QUAD8_CMR_QUADRATURE_X1 0x08
132 #define QUAD8_CMR_QUADRATURE_X2 0x10
133 #define QUAD8_CMR_QUADRATURE_X4 0x18
134 
135 static int quad8_signal_read(struct counter_device *counter,
136 			     struct counter_signal *signal,
137 			     enum counter_signal_level *level)
138 {
139 	const struct quad8 *const priv = counter_priv(counter);
140 	unsigned int state;
141 
142 	/* Only Index signal levels can be read */
143 	if (signal->id < 16)
144 		return -EINVAL;
145 
146 	state = ioread8(&priv->reg->index_input_levels) & BIT(signal->id - 16);
147 
148 	*level = (state) ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
149 
150 	return 0;
151 }
152 
153 static int quad8_count_read(struct counter_device *counter,
154 			    struct counter_count *count, u64 *val)
155 {
156 	struct quad8 *const priv = counter_priv(counter);
157 	struct channel_reg __iomem *const chan = priv->reg->channel + count->id;
158 	unsigned int flags;
159 	unsigned int borrow;
160 	unsigned int carry;
161 	unsigned long irqflags;
162 	int i;
163 
164 	flags = ioread8(&chan->control);
165 	borrow = flags & QUAD8_FLAG_BT;
166 	carry = !!(flags & QUAD8_FLAG_CT);
167 
168 	/* Borrow XOR Carry effectively doubles count range */
169 	*val = (unsigned long)(borrow ^ carry) << 24;
170 
171 	spin_lock_irqsave(&priv->lock, irqflags);
172 
173 	/* Reset Byte Pointer; transfer Counter to Output Latch */
174 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
175 		 &chan->control);
176 
177 	for (i = 0; i < 3; i++)
178 		*val |= (unsigned long)ioread8(&chan->data) << (8 * i);
179 
180 	spin_unlock_irqrestore(&priv->lock, irqflags);
181 
182 	return 0;
183 }
184 
185 static int quad8_count_write(struct counter_device *counter,
186 			     struct counter_count *count, u64 val)
187 {
188 	struct quad8 *const priv = counter_priv(counter);
189 	struct channel_reg __iomem *const chan = priv->reg->channel + count->id;
190 	unsigned long irqflags;
191 	int i;
192 
193 	/* Only 24-bit values are supported */
194 	if (val > 0xFFFFFF)
195 		return -ERANGE;
196 
197 	spin_lock_irqsave(&priv->lock, irqflags);
198 
199 	/* Reset Byte Pointer */
200 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
201 
202 	/* Counter can only be set via Preset Register */
203 	for (i = 0; i < 3; i++)
204 		iowrite8(val >> (8 * i), &chan->data);
205 
206 	/* Transfer Preset Register to Counter */
207 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, &chan->control);
208 
209 	/* Reset Byte Pointer */
210 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
211 
212 	/* Set Preset Register back to original value */
213 	val = priv->preset[count->id];
214 	for (i = 0; i < 3; i++)
215 		iowrite8(val >> (8 * i), &chan->data);
216 
217 	/* Reset Borrow, Carry, Compare, and Sign flags */
218 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, &chan->control);
219 	/* Reset Error flag */
220 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, &chan->control);
221 
222 	spin_unlock_irqrestore(&priv->lock, irqflags);
223 
224 	return 0;
225 }
226 
227 static const enum counter_function quad8_count_functions_list[] = {
228 	COUNTER_FUNCTION_PULSE_DIRECTION,
229 	COUNTER_FUNCTION_QUADRATURE_X1_A,
230 	COUNTER_FUNCTION_QUADRATURE_X2_A,
231 	COUNTER_FUNCTION_QUADRATURE_X4,
232 };
233 
234 static int quad8_function_read(struct counter_device *counter,
235 			       struct counter_count *count,
236 			       enum counter_function *function)
237 {
238 	struct quad8 *const priv = counter_priv(counter);
239 	const int id = count->id;
240 	unsigned long irqflags;
241 
242 	spin_lock_irqsave(&priv->lock, irqflags);
243 
244 	if (priv->quadrature_mode[id])
245 		switch (priv->quadrature_scale[id]) {
246 		case 0:
247 			*function = COUNTER_FUNCTION_QUADRATURE_X1_A;
248 			break;
249 		case 1:
250 			*function = COUNTER_FUNCTION_QUADRATURE_X2_A;
251 			break;
252 		case 2:
253 			*function = COUNTER_FUNCTION_QUADRATURE_X4;
254 			break;
255 		}
256 	else
257 		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
258 
259 	spin_unlock_irqrestore(&priv->lock, irqflags);
260 
261 	return 0;
262 }
263 
264 static int quad8_function_write(struct counter_device *counter,
265 				struct counter_count *count,
266 				enum counter_function function)
267 {
268 	struct quad8 *const priv = counter_priv(counter);
269 	const int id = count->id;
270 	unsigned int *const quadrature_mode = priv->quadrature_mode + id;
271 	unsigned int *const scale = priv->quadrature_scale + id;
272 	unsigned int *const synchronous_mode = priv->synchronous_mode + id;
273 	u8 __iomem *const control = &priv->reg->channel[id].control;
274 	unsigned long irqflags;
275 	unsigned int mode_cfg;
276 	unsigned int idr_cfg;
277 
278 	spin_lock_irqsave(&priv->lock, irqflags);
279 
280 	mode_cfg = priv->count_mode[id] << 1;
281 	idr_cfg = priv->index_polarity[id] << 1;
282 
283 	if (function == COUNTER_FUNCTION_PULSE_DIRECTION) {
284 		*quadrature_mode = 0;
285 
286 		/* Quadrature scaling only available in quadrature mode */
287 		*scale = 0;
288 
289 		/* Synchronous function not supported in non-quadrature mode */
290 		if (*synchronous_mode) {
291 			*synchronous_mode = 0;
292 			/* Disable synchronous function mode */
293 			iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
294 		}
295 	} else {
296 		*quadrature_mode = 1;
297 
298 		switch (function) {
299 		case COUNTER_FUNCTION_QUADRATURE_X1_A:
300 			*scale = 0;
301 			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
302 			break;
303 		case COUNTER_FUNCTION_QUADRATURE_X2_A:
304 			*scale = 1;
305 			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
306 			break;
307 		case COUNTER_FUNCTION_QUADRATURE_X4:
308 			*scale = 2;
309 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
310 			break;
311 		default:
312 			/* should never reach this path */
313 			spin_unlock_irqrestore(&priv->lock, irqflags);
314 			return -EINVAL;
315 		}
316 	}
317 
318 	/* Load mode configuration to Counter Mode Register */
319 	iowrite8(QUAD8_CTR_CMR | mode_cfg, control);
320 
321 	spin_unlock_irqrestore(&priv->lock, irqflags);
322 
323 	return 0;
324 }
325 
326 static int quad8_direction_read(struct counter_device *counter,
327 				struct counter_count *count,
328 				enum counter_count_direction *direction)
329 {
330 	const struct quad8 *const priv = counter_priv(counter);
331 	unsigned int ud_flag;
332 	u8 __iomem *const flag_addr = &priv->reg->channel[count->id].control;
333 
334 	/* U/D flag: nonzero = up, zero = down */
335 	ud_flag = ioread8(flag_addr) & QUAD8_FLAG_UD;
336 
337 	*direction = (ud_flag) ? COUNTER_COUNT_DIRECTION_FORWARD :
338 		COUNTER_COUNT_DIRECTION_BACKWARD;
339 
340 	return 0;
341 }
342 
343 static const enum counter_synapse_action quad8_index_actions_list[] = {
344 	COUNTER_SYNAPSE_ACTION_NONE,
345 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
346 };
347 
348 static const enum counter_synapse_action quad8_synapse_actions_list[] = {
349 	COUNTER_SYNAPSE_ACTION_NONE,
350 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
351 	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
352 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
353 };
354 
355 static int quad8_action_read(struct counter_device *counter,
356 			     struct counter_count *count,
357 			     struct counter_synapse *synapse,
358 			     enum counter_synapse_action *action)
359 {
360 	struct quad8 *const priv = counter_priv(counter);
361 	int err;
362 	enum counter_function function;
363 	const size_t signal_a_id = count->synapses[0].signal->id;
364 	enum counter_count_direction direction;
365 
366 	/* Handle Index signals */
367 	if (synapse->signal->id >= 16) {
368 		if (priv->preset_enable[count->id])
369 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
370 		else
371 			*action = COUNTER_SYNAPSE_ACTION_NONE;
372 
373 		return 0;
374 	}
375 
376 	err = quad8_function_read(counter, count, &function);
377 	if (err)
378 		return err;
379 
380 	/* Default action mode */
381 	*action = COUNTER_SYNAPSE_ACTION_NONE;
382 
383 	/* Determine action mode based on current count function mode */
384 	switch (function) {
385 	case COUNTER_FUNCTION_PULSE_DIRECTION:
386 		if (synapse->signal->id == signal_a_id)
387 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
388 		return 0;
389 	case COUNTER_FUNCTION_QUADRATURE_X1_A:
390 		if (synapse->signal->id == signal_a_id) {
391 			err = quad8_direction_read(counter, count, &direction);
392 			if (err)
393 				return err;
394 
395 			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
396 				*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
397 			else
398 				*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
399 		}
400 		return 0;
401 	case COUNTER_FUNCTION_QUADRATURE_X2_A:
402 		if (synapse->signal->id == signal_a_id)
403 			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
404 		return 0;
405 	case COUNTER_FUNCTION_QUADRATURE_X4:
406 		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
407 		return 0;
408 	default:
409 		/* should never reach this path */
410 		return -EINVAL;
411 	}
412 }
413 
414 enum {
415 	QUAD8_EVENT_CARRY = 0,
416 	QUAD8_EVENT_COMPARE = 1,
417 	QUAD8_EVENT_CARRY_BORROW = 2,
418 	QUAD8_EVENT_INDEX = 3,
419 };
420 
421 static int quad8_events_configure(struct counter_device *counter)
422 {
423 	struct quad8 *const priv = counter_priv(counter);
424 	unsigned long irq_enabled = 0;
425 	unsigned long irqflags;
426 	struct counter_event_node *event_node;
427 	unsigned int next_irq_trigger;
428 	unsigned long ior_cfg;
429 
430 	spin_lock_irqsave(&priv->lock, irqflags);
431 
432 	list_for_each_entry(event_node, &counter->events_list, l) {
433 		switch (event_node->event) {
434 		case COUNTER_EVENT_OVERFLOW:
435 			next_irq_trigger = QUAD8_EVENT_CARRY;
436 			break;
437 		case COUNTER_EVENT_THRESHOLD:
438 			next_irq_trigger = QUAD8_EVENT_COMPARE;
439 			break;
440 		case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
441 			next_irq_trigger = QUAD8_EVENT_CARRY_BORROW;
442 			break;
443 		case COUNTER_EVENT_INDEX:
444 			next_irq_trigger = QUAD8_EVENT_INDEX;
445 			break;
446 		default:
447 			/* should never reach this path */
448 			spin_unlock_irqrestore(&priv->lock, irqflags);
449 			return -EINVAL;
450 		}
451 
452 		/* Skip configuration if it is the same as previously set */
453 		if (priv->irq_trigger[event_node->channel] == next_irq_trigger)
454 			continue;
455 
456 		/* Save new IRQ function configuration */
457 		priv->irq_trigger[event_node->channel] = next_irq_trigger;
458 
459 		/* Load configuration to I/O Control Register */
460 		ior_cfg = priv->ab_enable[event_node->channel] |
461 			  priv->preset_enable[event_node->channel] << 1 |
462 			  priv->irq_trigger[event_node->channel] << 3;
463 		iowrite8(QUAD8_CTR_IOR | ior_cfg,
464 			 &priv->reg->channel[event_node->channel].control);
465 
466 		/* Enable IRQ line */
467 		irq_enabled |= BIT(event_node->channel);
468 	}
469 
470 	iowrite8(irq_enabled, &priv->reg->index_interrupt);
471 
472 	spin_unlock_irqrestore(&priv->lock, irqflags);
473 
474 	return 0;
475 }
476 
477 static int quad8_watch_validate(struct counter_device *counter,
478 				const struct counter_watch *watch)
479 {
480 	struct counter_event_node *event_node;
481 
482 	if (watch->channel > QUAD8_NUM_COUNTERS - 1)
483 		return -EINVAL;
484 
485 	switch (watch->event) {
486 	case COUNTER_EVENT_OVERFLOW:
487 	case COUNTER_EVENT_THRESHOLD:
488 	case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
489 	case COUNTER_EVENT_INDEX:
490 		list_for_each_entry(event_node, &counter->next_events_list, l)
491 			if (watch->channel == event_node->channel &&
492 				watch->event != event_node->event)
493 				return -EINVAL;
494 		return 0;
495 	default:
496 		return -EINVAL;
497 	}
498 }
499 
500 static const struct counter_ops quad8_ops = {
501 	.signal_read = quad8_signal_read,
502 	.count_read = quad8_count_read,
503 	.count_write = quad8_count_write,
504 	.function_read = quad8_function_read,
505 	.function_write = quad8_function_write,
506 	.action_read = quad8_action_read,
507 	.events_configure = quad8_events_configure,
508 	.watch_validate = quad8_watch_validate,
509 };
510 
511 static const char *const quad8_index_polarity_modes[] = {
512 	"negative",
513 	"positive"
514 };
515 
516 static int quad8_index_polarity_get(struct counter_device *counter,
517 				    struct counter_signal *signal,
518 				    u32 *index_polarity)
519 {
520 	const struct quad8 *const priv = counter_priv(counter);
521 	const size_t channel_id = signal->id - 16;
522 
523 	*index_polarity = priv->index_polarity[channel_id];
524 
525 	return 0;
526 }
527 
528 static int quad8_index_polarity_set(struct counter_device *counter,
529 				    struct counter_signal *signal,
530 				    u32 index_polarity)
531 {
532 	struct quad8 *const priv = counter_priv(counter);
533 	const size_t channel_id = signal->id - 16;
534 	u8 __iomem *const control = &priv->reg->channel[channel_id].control;
535 	unsigned long irqflags;
536 	unsigned int idr_cfg = index_polarity << 1;
537 
538 	spin_lock_irqsave(&priv->lock, irqflags);
539 
540 	idr_cfg |= priv->synchronous_mode[channel_id];
541 
542 	priv->index_polarity[channel_id] = index_polarity;
543 
544 	/* Load Index Control configuration to Index Control Register */
545 	iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
546 
547 	spin_unlock_irqrestore(&priv->lock, irqflags);
548 
549 	return 0;
550 }
551 
552 static const char *const quad8_synchronous_modes[] = {
553 	"non-synchronous",
554 	"synchronous"
555 };
556 
557 static int quad8_synchronous_mode_get(struct counter_device *counter,
558 				      struct counter_signal *signal,
559 				      u32 *synchronous_mode)
560 {
561 	const struct quad8 *const priv = counter_priv(counter);
562 	const size_t channel_id = signal->id - 16;
563 
564 	*synchronous_mode = priv->synchronous_mode[channel_id];
565 
566 	return 0;
567 }
568 
569 static int quad8_synchronous_mode_set(struct counter_device *counter,
570 				      struct counter_signal *signal,
571 				      u32 synchronous_mode)
572 {
573 	struct quad8 *const priv = counter_priv(counter);
574 	const size_t channel_id = signal->id - 16;
575 	u8 __iomem *const control = &priv->reg->channel[channel_id].control;
576 	unsigned long irqflags;
577 	unsigned int idr_cfg = synchronous_mode;
578 
579 	spin_lock_irqsave(&priv->lock, irqflags);
580 
581 	idr_cfg |= priv->index_polarity[channel_id] << 1;
582 
583 	/* Index function must be non-synchronous in non-quadrature mode */
584 	if (synchronous_mode && !priv->quadrature_mode[channel_id]) {
585 		spin_unlock_irqrestore(&priv->lock, irqflags);
586 		return -EINVAL;
587 	}
588 
589 	priv->synchronous_mode[channel_id] = synchronous_mode;
590 
591 	/* Load Index Control configuration to Index Control Register */
592 	iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
593 
594 	spin_unlock_irqrestore(&priv->lock, irqflags);
595 
596 	return 0;
597 }
598 
599 static int quad8_count_floor_read(struct counter_device *counter,
600 				  struct counter_count *count, u64 *floor)
601 {
602 	/* Only a floor of 0 is supported */
603 	*floor = 0;
604 
605 	return 0;
606 }
607 
608 static int quad8_count_mode_read(struct counter_device *counter,
609 				 struct counter_count *count,
610 				 enum counter_count_mode *cnt_mode)
611 {
612 	const struct quad8 *const priv = counter_priv(counter);
613 
614 	/* Map 104-QUAD-8 count mode to Generic Counter count mode */
615 	switch (priv->count_mode[count->id]) {
616 	case 0:
617 		*cnt_mode = COUNTER_COUNT_MODE_NORMAL;
618 		break;
619 	case 1:
620 		*cnt_mode = COUNTER_COUNT_MODE_RANGE_LIMIT;
621 		break;
622 	case 2:
623 		*cnt_mode = COUNTER_COUNT_MODE_NON_RECYCLE;
624 		break;
625 	case 3:
626 		*cnt_mode = COUNTER_COUNT_MODE_MODULO_N;
627 		break;
628 	}
629 
630 	return 0;
631 }
632 
633 static int quad8_count_mode_write(struct counter_device *counter,
634 				  struct counter_count *count,
635 				  enum counter_count_mode cnt_mode)
636 {
637 	struct quad8 *const priv = counter_priv(counter);
638 	unsigned int count_mode;
639 	unsigned int mode_cfg;
640 	u8 __iomem *const control = &priv->reg->channel[count->id].control;
641 	unsigned long irqflags;
642 
643 	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
644 	switch (cnt_mode) {
645 	case COUNTER_COUNT_MODE_NORMAL:
646 		count_mode = 0;
647 		break;
648 	case COUNTER_COUNT_MODE_RANGE_LIMIT:
649 		count_mode = 1;
650 		break;
651 	case COUNTER_COUNT_MODE_NON_RECYCLE:
652 		count_mode = 2;
653 		break;
654 	case COUNTER_COUNT_MODE_MODULO_N:
655 		count_mode = 3;
656 		break;
657 	default:
658 		/* should never reach this path */
659 		return -EINVAL;
660 	}
661 
662 	spin_lock_irqsave(&priv->lock, irqflags);
663 
664 	priv->count_mode[count->id] = count_mode;
665 
666 	/* Set count mode configuration value */
667 	mode_cfg = count_mode << 1;
668 
669 	/* Add quadrature mode configuration */
670 	if (priv->quadrature_mode[count->id])
671 		mode_cfg |= (priv->quadrature_scale[count->id] + 1) << 3;
672 
673 	/* Load mode configuration to Counter Mode Register */
674 	iowrite8(QUAD8_CTR_CMR | mode_cfg, control);
675 
676 	spin_unlock_irqrestore(&priv->lock, irqflags);
677 
678 	return 0;
679 }
680 
681 static int quad8_count_enable_read(struct counter_device *counter,
682 				   struct counter_count *count, u8 *enable)
683 {
684 	const struct quad8 *const priv = counter_priv(counter);
685 
686 	*enable = priv->ab_enable[count->id];
687 
688 	return 0;
689 }
690 
691 static int quad8_count_enable_write(struct counter_device *counter,
692 				    struct counter_count *count, u8 enable)
693 {
694 	struct quad8 *const priv = counter_priv(counter);
695 	u8 __iomem *const control = &priv->reg->channel[count->id].control;
696 	unsigned long irqflags;
697 	unsigned int ior_cfg;
698 
699 	spin_lock_irqsave(&priv->lock, irqflags);
700 
701 	priv->ab_enable[count->id] = enable;
702 
703 	ior_cfg = enable | priv->preset_enable[count->id] << 1 |
704 		  priv->irq_trigger[count->id] << 3;
705 
706 	/* Load I/O control configuration */
707 	iowrite8(QUAD8_CTR_IOR | ior_cfg, control);
708 
709 	spin_unlock_irqrestore(&priv->lock, irqflags);
710 
711 	return 0;
712 }
713 
714 static const char *const quad8_noise_error_states[] = {
715 	"No excessive noise is present at the count inputs",
716 	"Excessive noise is present at the count inputs"
717 };
718 
719 static int quad8_error_noise_get(struct counter_device *counter,
720 				 struct counter_count *count, u32 *noise_error)
721 {
722 	const struct quad8 *const priv = counter_priv(counter);
723 	u8 __iomem *const flag_addr = &priv->reg->channel[count->id].control;
724 
725 	*noise_error = !!(ioread8(flag_addr) & QUAD8_FLAG_E);
726 
727 	return 0;
728 }
729 
730 static int quad8_count_preset_read(struct counter_device *counter,
731 				   struct counter_count *count, u64 *preset)
732 {
733 	const struct quad8 *const priv = counter_priv(counter);
734 
735 	*preset = priv->preset[count->id];
736 
737 	return 0;
738 }
739 
740 static void quad8_preset_register_set(struct quad8 *const priv, const int id,
741 				      const unsigned int preset)
742 {
743 	struct channel_reg __iomem *const chan = priv->reg->channel + id;
744 	int i;
745 
746 	priv->preset[id] = preset;
747 
748 	/* Reset Byte Pointer */
749 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
750 
751 	/* Set Preset Register */
752 	for (i = 0; i < 3; i++)
753 		iowrite8(preset >> (8 * i), &chan->data);
754 }
755 
756 static int quad8_count_preset_write(struct counter_device *counter,
757 				    struct counter_count *count, u64 preset)
758 {
759 	struct quad8 *const priv = counter_priv(counter);
760 	unsigned long irqflags;
761 
762 	/* Only 24-bit values are supported */
763 	if (preset > 0xFFFFFF)
764 		return -ERANGE;
765 
766 	spin_lock_irqsave(&priv->lock, irqflags);
767 
768 	quad8_preset_register_set(priv, count->id, preset);
769 
770 	spin_unlock_irqrestore(&priv->lock, irqflags);
771 
772 	return 0;
773 }
774 
775 static int quad8_count_ceiling_read(struct counter_device *counter,
776 				    struct counter_count *count, u64 *ceiling)
777 {
778 	struct quad8 *const priv = counter_priv(counter);
779 	unsigned long irqflags;
780 
781 	spin_lock_irqsave(&priv->lock, irqflags);
782 
783 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
784 	switch (priv->count_mode[count->id]) {
785 	case 1:
786 	case 3:
787 		*ceiling = priv->preset[count->id];
788 		break;
789 	default:
790 		/* By default 0x1FFFFFF (25 bits unsigned) is maximum count */
791 		*ceiling = 0x1FFFFFF;
792 		break;
793 	}
794 
795 	spin_unlock_irqrestore(&priv->lock, irqflags);
796 
797 	return 0;
798 }
799 
800 static int quad8_count_ceiling_write(struct counter_device *counter,
801 				     struct counter_count *count, u64 ceiling)
802 {
803 	struct quad8 *const priv = counter_priv(counter);
804 	unsigned long irqflags;
805 
806 	/* Only 24-bit values are supported */
807 	if (ceiling > 0xFFFFFF)
808 		return -ERANGE;
809 
810 	spin_lock_irqsave(&priv->lock, irqflags);
811 
812 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
813 	switch (priv->count_mode[count->id]) {
814 	case 1:
815 	case 3:
816 		quad8_preset_register_set(priv, count->id, ceiling);
817 		spin_unlock_irqrestore(&priv->lock, irqflags);
818 		return 0;
819 	}
820 
821 	spin_unlock_irqrestore(&priv->lock, irqflags);
822 
823 	return -EINVAL;
824 }
825 
826 static int quad8_count_preset_enable_read(struct counter_device *counter,
827 					  struct counter_count *count,
828 					  u8 *preset_enable)
829 {
830 	const struct quad8 *const priv = counter_priv(counter);
831 
832 	*preset_enable = !priv->preset_enable[count->id];
833 
834 	return 0;
835 }
836 
837 static int quad8_count_preset_enable_write(struct counter_device *counter,
838 					   struct counter_count *count,
839 					   u8 preset_enable)
840 {
841 	struct quad8 *const priv = counter_priv(counter);
842 	u8 __iomem *const control = &priv->reg->channel[count->id].control;
843 	unsigned long irqflags;
844 	unsigned int ior_cfg;
845 
846 	/* Preset enable is active low in Input/Output Control register */
847 	preset_enable = !preset_enable;
848 
849 	spin_lock_irqsave(&priv->lock, irqflags);
850 
851 	priv->preset_enable[count->id] = preset_enable;
852 
853 	ior_cfg = priv->ab_enable[count->id] | preset_enable << 1 |
854 		  priv->irq_trigger[count->id] << 3;
855 
856 	/* Load I/O control configuration to Input / Output Control Register */
857 	iowrite8(QUAD8_CTR_IOR | ior_cfg, control);
858 
859 	spin_unlock_irqrestore(&priv->lock, irqflags);
860 
861 	return 0;
862 }
863 
864 static int quad8_signal_cable_fault_read(struct counter_device *counter,
865 					 struct counter_signal *signal,
866 					 u8 *cable_fault)
867 {
868 	struct quad8 *const priv = counter_priv(counter);
869 	const size_t channel_id = signal->id / 2;
870 	unsigned long irqflags;
871 	bool disabled;
872 	unsigned int status;
873 
874 	spin_lock_irqsave(&priv->lock, irqflags);
875 
876 	disabled = !(priv->cable_fault_enable & BIT(channel_id));
877 
878 	if (disabled) {
879 		spin_unlock_irqrestore(&priv->lock, irqflags);
880 		return -EINVAL;
881 	}
882 
883 	/* Logic 0 = cable fault */
884 	status = ioread8(&priv->reg->cable_status);
885 
886 	spin_unlock_irqrestore(&priv->lock, irqflags);
887 
888 	/* Mask respective channel and invert logic */
889 	*cable_fault = !(status & BIT(channel_id));
890 
891 	return 0;
892 }
893 
894 static int quad8_signal_cable_fault_enable_read(struct counter_device *counter,
895 						struct counter_signal *signal,
896 						u8 *enable)
897 {
898 	const struct quad8 *const priv = counter_priv(counter);
899 	const size_t channel_id = signal->id / 2;
900 
901 	*enable = !!(priv->cable_fault_enable & BIT(channel_id));
902 
903 	return 0;
904 }
905 
906 static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
907 						 struct counter_signal *signal,
908 						 u8 enable)
909 {
910 	struct quad8 *const priv = counter_priv(counter);
911 	const size_t channel_id = signal->id / 2;
912 	unsigned long irqflags;
913 	unsigned int cable_fault_enable;
914 
915 	spin_lock_irqsave(&priv->lock, irqflags);
916 
917 	if (enable)
918 		priv->cable_fault_enable |= BIT(channel_id);
919 	else
920 		priv->cable_fault_enable &= ~BIT(channel_id);
921 
922 	/* Enable is active low in Differential Encoder Cable Status register */
923 	cable_fault_enable = ~priv->cable_fault_enable;
924 
925 	iowrite8(cable_fault_enable, &priv->reg->cable_status);
926 
927 	spin_unlock_irqrestore(&priv->lock, irqflags);
928 
929 	return 0;
930 }
931 
932 static int quad8_signal_fck_prescaler_read(struct counter_device *counter,
933 					   struct counter_signal *signal,
934 					   u8 *prescaler)
935 {
936 	const struct quad8 *const priv = counter_priv(counter);
937 
938 	*prescaler = priv->fck_prescaler[signal->id / 2];
939 
940 	return 0;
941 }
942 
943 static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
944 					    struct counter_signal *signal,
945 					    u8 prescaler)
946 {
947 	struct quad8 *const priv = counter_priv(counter);
948 	const size_t channel_id = signal->id / 2;
949 	struct channel_reg __iomem *const chan = priv->reg->channel + channel_id;
950 	unsigned long irqflags;
951 
952 	spin_lock_irqsave(&priv->lock, irqflags);
953 
954 	priv->fck_prescaler[channel_id] = prescaler;
955 
956 	/* Reset Byte Pointer */
957 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
958 
959 	/* Set filter clock factor */
960 	iowrite8(prescaler, &chan->data);
961 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
962 		 &chan->control);
963 
964 	spin_unlock_irqrestore(&priv->lock, irqflags);
965 
966 	return 0;
967 }
968 
969 static struct counter_comp quad8_signal_ext[] = {
970 	COUNTER_COMP_SIGNAL_BOOL("cable_fault", quad8_signal_cable_fault_read,
971 				 NULL),
972 	COUNTER_COMP_SIGNAL_BOOL("cable_fault_enable",
973 				 quad8_signal_cable_fault_enable_read,
974 				 quad8_signal_cable_fault_enable_write),
975 	COUNTER_COMP_SIGNAL_U8("filter_clock_prescaler",
976 			       quad8_signal_fck_prescaler_read,
977 			       quad8_signal_fck_prescaler_write)
978 };
979 
980 static DEFINE_COUNTER_ENUM(quad8_index_pol_enum, quad8_index_polarity_modes);
981 static DEFINE_COUNTER_ENUM(quad8_synch_mode_enum, quad8_synchronous_modes);
982 
983 static struct counter_comp quad8_index_ext[] = {
984 	COUNTER_COMP_SIGNAL_ENUM("index_polarity", quad8_index_polarity_get,
985 				 quad8_index_polarity_set,
986 				 quad8_index_pol_enum),
987 	COUNTER_COMP_SIGNAL_ENUM("synchronous_mode", quad8_synchronous_mode_get,
988 				 quad8_synchronous_mode_set,
989 				 quad8_synch_mode_enum),
990 };
991 
992 #define QUAD8_QUAD_SIGNAL(_id, _name) {		\
993 	.id = (_id),				\
994 	.name = (_name),			\
995 	.ext = quad8_signal_ext,		\
996 	.num_ext = ARRAY_SIZE(quad8_signal_ext)	\
997 }
998 
999 #define	QUAD8_INDEX_SIGNAL(_id, _name) {	\
1000 	.id = (_id),				\
1001 	.name = (_name),			\
1002 	.ext = quad8_index_ext,			\
1003 	.num_ext = ARRAY_SIZE(quad8_index_ext)	\
1004 }
1005 
1006 static struct counter_signal quad8_signals[] = {
1007 	QUAD8_QUAD_SIGNAL(0, "Channel 1 Quadrature A"),
1008 	QUAD8_QUAD_SIGNAL(1, "Channel 1 Quadrature B"),
1009 	QUAD8_QUAD_SIGNAL(2, "Channel 2 Quadrature A"),
1010 	QUAD8_QUAD_SIGNAL(3, "Channel 2 Quadrature B"),
1011 	QUAD8_QUAD_SIGNAL(4, "Channel 3 Quadrature A"),
1012 	QUAD8_QUAD_SIGNAL(5, "Channel 3 Quadrature B"),
1013 	QUAD8_QUAD_SIGNAL(6, "Channel 4 Quadrature A"),
1014 	QUAD8_QUAD_SIGNAL(7, "Channel 4 Quadrature B"),
1015 	QUAD8_QUAD_SIGNAL(8, "Channel 5 Quadrature A"),
1016 	QUAD8_QUAD_SIGNAL(9, "Channel 5 Quadrature B"),
1017 	QUAD8_QUAD_SIGNAL(10, "Channel 6 Quadrature A"),
1018 	QUAD8_QUAD_SIGNAL(11, "Channel 6 Quadrature B"),
1019 	QUAD8_QUAD_SIGNAL(12, "Channel 7 Quadrature A"),
1020 	QUAD8_QUAD_SIGNAL(13, "Channel 7 Quadrature B"),
1021 	QUAD8_QUAD_SIGNAL(14, "Channel 8 Quadrature A"),
1022 	QUAD8_QUAD_SIGNAL(15, "Channel 8 Quadrature B"),
1023 	QUAD8_INDEX_SIGNAL(16, "Channel 1 Index"),
1024 	QUAD8_INDEX_SIGNAL(17, "Channel 2 Index"),
1025 	QUAD8_INDEX_SIGNAL(18, "Channel 3 Index"),
1026 	QUAD8_INDEX_SIGNAL(19, "Channel 4 Index"),
1027 	QUAD8_INDEX_SIGNAL(20, "Channel 5 Index"),
1028 	QUAD8_INDEX_SIGNAL(21, "Channel 6 Index"),
1029 	QUAD8_INDEX_SIGNAL(22, "Channel 7 Index"),
1030 	QUAD8_INDEX_SIGNAL(23, "Channel 8 Index")
1031 };
1032 
1033 #define QUAD8_COUNT_SYNAPSES(_id) {					\
1034 	{								\
1035 		.actions_list = quad8_synapse_actions_list,		\
1036 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1037 		.signal = quad8_signals + 2 * (_id)			\
1038 	},								\
1039 	{								\
1040 		.actions_list = quad8_synapse_actions_list,		\
1041 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1042 		.signal = quad8_signals + 2 * (_id) + 1			\
1043 	},								\
1044 	{								\
1045 		.actions_list = quad8_index_actions_list,		\
1046 		.num_actions = ARRAY_SIZE(quad8_index_actions_list),	\
1047 		.signal = quad8_signals + 2 * (_id) + 16		\
1048 	}								\
1049 }
1050 
1051 static struct counter_synapse quad8_count_synapses[][3] = {
1052 	QUAD8_COUNT_SYNAPSES(0), QUAD8_COUNT_SYNAPSES(1),
1053 	QUAD8_COUNT_SYNAPSES(2), QUAD8_COUNT_SYNAPSES(3),
1054 	QUAD8_COUNT_SYNAPSES(4), QUAD8_COUNT_SYNAPSES(5),
1055 	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
1056 };
1057 
1058 static const enum counter_count_mode quad8_cnt_modes[] = {
1059 	COUNTER_COUNT_MODE_NORMAL,
1060 	COUNTER_COUNT_MODE_RANGE_LIMIT,
1061 	COUNTER_COUNT_MODE_NON_RECYCLE,
1062 	COUNTER_COUNT_MODE_MODULO_N,
1063 };
1064 
1065 static DEFINE_COUNTER_AVAILABLE(quad8_count_mode_available, quad8_cnt_modes);
1066 
1067 static DEFINE_COUNTER_ENUM(quad8_error_noise_enum, quad8_noise_error_states);
1068 
1069 static struct counter_comp quad8_count_ext[] = {
1070 	COUNTER_COMP_CEILING(quad8_count_ceiling_read,
1071 			     quad8_count_ceiling_write),
1072 	COUNTER_COMP_FLOOR(quad8_count_floor_read, NULL),
1073 	COUNTER_COMP_COUNT_MODE(quad8_count_mode_read, quad8_count_mode_write,
1074 				quad8_count_mode_available),
1075 	COUNTER_COMP_DIRECTION(quad8_direction_read),
1076 	COUNTER_COMP_ENABLE(quad8_count_enable_read, quad8_count_enable_write),
1077 	COUNTER_COMP_COUNT_ENUM("error_noise", quad8_error_noise_get, NULL,
1078 				quad8_error_noise_enum),
1079 	COUNTER_COMP_PRESET(quad8_count_preset_read, quad8_count_preset_write),
1080 	COUNTER_COMP_PRESET_ENABLE(quad8_count_preset_enable_read,
1081 				   quad8_count_preset_enable_write),
1082 };
1083 
1084 #define QUAD8_COUNT(_id, _cntname) {					\
1085 	.id = (_id),							\
1086 	.name = (_cntname),						\
1087 	.functions_list = quad8_count_functions_list,			\
1088 	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
1089 	.synapses = quad8_count_synapses[(_id)],			\
1090 	.num_synapses =	2,						\
1091 	.ext = quad8_count_ext,						\
1092 	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
1093 }
1094 
1095 static struct counter_count quad8_counts[] = {
1096 	QUAD8_COUNT(0, "Channel 1 Count"),
1097 	QUAD8_COUNT(1, "Channel 2 Count"),
1098 	QUAD8_COUNT(2, "Channel 3 Count"),
1099 	QUAD8_COUNT(3, "Channel 4 Count"),
1100 	QUAD8_COUNT(4, "Channel 5 Count"),
1101 	QUAD8_COUNT(5, "Channel 6 Count"),
1102 	QUAD8_COUNT(6, "Channel 7 Count"),
1103 	QUAD8_COUNT(7, "Channel 8 Count")
1104 };
1105 
1106 static irqreturn_t quad8_irq_handler(int irq, void *private)
1107 {
1108 	struct counter_device *counter = private;
1109 	struct quad8 *const priv = counter_priv(counter);
1110 	unsigned long irq_status;
1111 	unsigned long channel;
1112 	u8 event;
1113 
1114 	irq_status = ioread8(&priv->reg->interrupt_status);
1115 	if (!irq_status)
1116 		return IRQ_NONE;
1117 
1118 	for_each_set_bit(channel, &irq_status, QUAD8_NUM_COUNTERS) {
1119 		switch (priv->irq_trigger[channel]) {
1120 		case QUAD8_EVENT_CARRY:
1121 			event = COUNTER_EVENT_OVERFLOW;
1122 				break;
1123 		case QUAD8_EVENT_COMPARE:
1124 			event = COUNTER_EVENT_THRESHOLD;
1125 				break;
1126 		case QUAD8_EVENT_CARRY_BORROW:
1127 			event = COUNTER_EVENT_OVERFLOW_UNDERFLOW;
1128 				break;
1129 		case QUAD8_EVENT_INDEX:
1130 			event = COUNTER_EVENT_INDEX;
1131 				break;
1132 		default:
1133 			/* should never reach this path */
1134 			WARN_ONCE(true, "invalid interrupt trigger function %u configured for channel %lu\n",
1135 				  priv->irq_trigger[channel], channel);
1136 			continue;
1137 		}
1138 
1139 		counter_push_event(counter, event, channel);
1140 	}
1141 
1142 	/* Clear pending interrupts on device */
1143 	iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, &priv->reg->channel_oper);
1144 
1145 	return IRQ_HANDLED;
1146 }
1147 
1148 static void quad8_init_counter(struct channel_reg __iomem *const chan)
1149 {
1150 	unsigned long i;
1151 
1152 	/* Reset Byte Pointer */
1153 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
1154 	/* Reset filter clock factor */
1155 	iowrite8(0, &chan->data);
1156 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
1157 		 &chan->control);
1158 	/* Reset Byte Pointer */
1159 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
1160 	/* Reset Preset Register */
1161 	for (i = 0; i < 3; i++)
1162 		iowrite8(0x00, &chan->data);
1163 	/* Reset Borrow, Carry, Compare, and Sign flags */
1164 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, &chan->control);
1165 	/* Reset Error flag */
1166 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, &chan->control);
1167 	/* Binary encoding; Normal count; non-quadrature mode */
1168 	iowrite8(QUAD8_CTR_CMR, &chan->control);
1169 	/* Disable A and B inputs; preset on index; FLG1 as Carry */
1170 	iowrite8(QUAD8_CTR_IOR, &chan->control);
1171 	/* Disable index function; negative index polarity */
1172 	iowrite8(QUAD8_CTR_IDR, &chan->control);
1173 }
1174 
1175 static int quad8_probe(struct device *dev, unsigned int id)
1176 {
1177 	struct counter_device *counter;
1178 	struct quad8 *priv;
1179 	unsigned long i;
1180 	int err;
1181 
1182 	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
1183 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
1184 			base[id], base[id] + QUAD8_EXTENT);
1185 		return -EBUSY;
1186 	}
1187 
1188 	counter = devm_counter_alloc(dev, sizeof(*priv));
1189 	if (!counter)
1190 		return -ENOMEM;
1191 	priv = counter_priv(counter);
1192 
1193 	priv->reg = devm_ioport_map(dev, base[id], QUAD8_EXTENT);
1194 	if (!priv->reg)
1195 		return -ENOMEM;
1196 
1197 	/* Initialize Counter device and driver data */
1198 	counter->name = dev_name(dev);
1199 	counter->parent = dev;
1200 	counter->ops = &quad8_ops;
1201 	counter->counts = quad8_counts;
1202 	counter->num_counts = ARRAY_SIZE(quad8_counts);
1203 	counter->signals = quad8_signals;
1204 	counter->num_signals = ARRAY_SIZE(quad8_signals);
1205 
1206 	spin_lock_init(&priv->lock);
1207 
1208 	/* Reset Index/Interrupt Register */
1209 	iowrite8(0x00, &priv->reg->index_interrupt);
1210 	/* Reset all counters and disable interrupt function */
1211 	iowrite8(QUAD8_CHAN_OP_RESET_COUNTERS, &priv->reg->channel_oper);
1212 	/* Set initial configuration for all counters */
1213 	for (i = 0; i < QUAD8_NUM_COUNTERS; i++)
1214 		quad8_init_counter(priv->reg->channel + i);
1215 	/* Disable Differential Encoder Cable Status for all channels */
1216 	iowrite8(0xFF, &priv->reg->cable_status);
1217 	/* Enable all counters and enable interrupt function */
1218 	iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, &priv->reg->channel_oper);
1219 
1220 	err = devm_request_irq(&counter->dev, irq[id], quad8_irq_handler,
1221 			       IRQF_SHARED, counter->name, counter);
1222 	if (err)
1223 		return err;
1224 
1225 	err = devm_counter_add(dev, counter);
1226 	if (err < 0)
1227 		return dev_err_probe(dev, err, "Failed to add counter\n");
1228 
1229 	return 0;
1230 }
1231 
1232 static struct isa_driver quad8_driver = {
1233 	.probe = quad8_probe,
1234 	.driver = {
1235 		.name = "104-quad-8"
1236 	}
1237 };
1238 
1239 module_isa_driver(quad8_driver, num_quad8);
1240 
1241 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
1242 MODULE_DESCRIPTION("ACCES 104-QUAD-8 driver");
1243 MODULE_LICENSE("GPL v2");
1244