xref: /openbmc/linux/drivers/counter/104-quad-8.c (revision fa0dadde)
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 static unsigned int num_irq;
32 module_param_hw_array(irq, uint, irq, &num_irq, 0);
33 MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
34 
35 #define QUAD8_NUM_COUNTERS 8
36 
37 /**
38  * struct channel_reg - channel register structure
39  * @data:	Count data
40  * @control:	Channel flags and control
41  */
42 struct channel_reg {
43 	u8 data;
44 	u8 control;
45 };
46 
47 /**
48  * struct quad8_reg - device register structure
49  * @channel:		quadrature counter data and control
50  * @interrupt_status:	channel interrupt status
51  * @channel_oper:	enable/reset counters and interrupt functions
52  * @index_interrupt:	enable channel interrupts
53  * @reserved:		reserved for Factory Use
54  * @index_input_levels:	index signal logical input level
55  * @cable_status:	differential encoder cable status
56  */
57 struct quad8_reg {
58 	struct channel_reg channel[QUAD8_NUM_COUNTERS];
59 	u8 interrupt_status;
60 	u8 channel_oper;
61 	u8 index_interrupt;
62 	u8 reserved[3];
63 	u8 index_input_levels;
64 	u8 cable_status;
65 };
66 
67 /**
68  * struct quad8 - device private data structure
69  * @lock:		lock to prevent clobbering device states during R/W ops
70  * @counter:		instance of the counter_device
71  * @fck_prescaler:	array of filter clock prescaler configurations
72  * @preset:		array of preset values
73  * @count_mode:		array of count mode configurations
74  * @quadrature_mode:	array of quadrature mode configurations
75  * @quadrature_scale:	array of quadrature mode scale configurations
76  * @ab_enable:		array of A and B inputs enable configurations
77  * @preset_enable:	array of set_to_preset_on_index attribute configurations
78  * @irq_trigger:	array of current IRQ trigger function configurations
79  * @synchronous_mode:	array of index function synchronous mode configurations
80  * @index_polarity:	array of index function polarity configurations
81  * @cable_fault_enable:	differential encoder cable status enable configurations
82  * @reg:		I/O address offset for the device registers
83  */
84 struct quad8 {
85 	spinlock_t lock;
86 	unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
87 	unsigned int preset[QUAD8_NUM_COUNTERS];
88 	unsigned int count_mode[QUAD8_NUM_COUNTERS];
89 	unsigned int quadrature_mode[QUAD8_NUM_COUNTERS];
90 	unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
91 	unsigned int ab_enable[QUAD8_NUM_COUNTERS];
92 	unsigned int preset_enable[QUAD8_NUM_COUNTERS];
93 	unsigned int irq_trigger[QUAD8_NUM_COUNTERS];
94 	unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
95 	unsigned int index_polarity[QUAD8_NUM_COUNTERS];
96 	unsigned int cable_fault_enable;
97 	struct quad8_reg __iomem *reg;
98 };
99 
100 /* Error flag */
101 #define QUAD8_FLAG_E BIT(4)
102 /* Up/Down flag */
103 #define QUAD8_FLAG_UD BIT(5)
104 /* Reset and Load Signal Decoders */
105 #define QUAD8_CTR_RLD 0x00
106 /* Counter Mode Register */
107 #define QUAD8_CTR_CMR 0x20
108 /* Input / Output Control Register */
109 #define QUAD8_CTR_IOR 0x40
110 /* Index Control Register */
111 #define QUAD8_CTR_IDR 0x60
112 /* Reset Byte Pointer (three byte data pointer) */
113 #define QUAD8_RLD_RESET_BP 0x01
114 /* Reset Counter */
115 #define QUAD8_RLD_RESET_CNTR 0x02
116 /* Reset Borrow Toggle, Carry Toggle, Compare Toggle, and Sign flags */
117 #define QUAD8_RLD_RESET_FLAGS 0x04
118 /* Reset Error flag */
119 #define QUAD8_RLD_RESET_E 0x06
120 /* Preset Register to Counter */
121 #define QUAD8_RLD_PRESET_CNTR 0x08
122 /* Transfer Counter to Output Latch */
123 #define QUAD8_RLD_CNTR_OUT 0x10
124 /* Transfer Preset Register LSB to FCK Prescaler */
125 #define QUAD8_RLD_PRESET_PSC 0x18
126 #define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
127 #define QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC 0x04
128 #define QUAD8_CMR_QUADRATURE_X1 0x08
129 #define QUAD8_CMR_QUADRATURE_X2 0x10
130 #define QUAD8_CMR_QUADRATURE_X4 0x18
131 
132 /* Each Counter is 24 bits wide */
133 #define LS7267_CNTR_MAX GENMASK(23, 0)
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 long irqflags;
159 	int i;
160 
161 	*val = 0;
162 
163 	spin_lock_irqsave(&priv->lock, irqflags);
164 
165 	/* Reset Byte Pointer; transfer Counter to Output Latch */
166 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
167 		 &chan->control);
168 
169 	for (i = 0; i < 3; i++)
170 		*val |= (unsigned long)ioread8(&chan->data) << (8 * i);
171 
172 	spin_unlock_irqrestore(&priv->lock, irqflags);
173 
174 	return 0;
175 }
176 
177 static int quad8_count_write(struct counter_device *counter,
178 			     struct counter_count *count, u64 val)
179 {
180 	struct quad8 *const priv = counter_priv(counter);
181 	struct channel_reg __iomem *const chan = priv->reg->channel + count->id;
182 	unsigned long irqflags;
183 	int i;
184 
185 	if (val > LS7267_CNTR_MAX)
186 		return -ERANGE;
187 
188 	spin_lock_irqsave(&priv->lock, irqflags);
189 
190 	/* Reset Byte Pointer */
191 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
192 
193 	/* Counter can only be set via Preset Register */
194 	for (i = 0; i < 3; i++)
195 		iowrite8(val >> (8 * i), &chan->data);
196 
197 	/* Transfer Preset Register to Counter */
198 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, &chan->control);
199 
200 	/* Reset Byte Pointer */
201 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
202 
203 	/* Set Preset Register back to original value */
204 	val = priv->preset[count->id];
205 	for (i = 0; i < 3; i++)
206 		iowrite8(val >> (8 * i), &chan->data);
207 
208 	/* Reset Borrow, Carry, Compare, and Sign flags */
209 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, &chan->control);
210 	/* Reset Error flag */
211 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, &chan->control);
212 
213 	spin_unlock_irqrestore(&priv->lock, irqflags);
214 
215 	return 0;
216 }
217 
218 static const enum counter_function quad8_count_functions_list[] = {
219 	COUNTER_FUNCTION_PULSE_DIRECTION,
220 	COUNTER_FUNCTION_QUADRATURE_X1_A,
221 	COUNTER_FUNCTION_QUADRATURE_X2_A,
222 	COUNTER_FUNCTION_QUADRATURE_X4,
223 };
224 
225 static int quad8_function_get(const struct quad8 *const priv, const size_t id,
226 			      enum counter_function *const function)
227 {
228 	if (!priv->quadrature_mode[id]) {
229 		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
230 		return 0;
231 	}
232 
233 	switch (priv->quadrature_scale[id]) {
234 	case 0:
235 		*function = COUNTER_FUNCTION_QUADRATURE_X1_A;
236 		return 0;
237 	case 1:
238 		*function = COUNTER_FUNCTION_QUADRATURE_X2_A;
239 		return 0;
240 	case 2:
241 		*function = COUNTER_FUNCTION_QUADRATURE_X4;
242 		return 0;
243 	default:
244 		/* should never reach this path */
245 		return -EINVAL;
246 	}
247 }
248 
249 static int quad8_function_read(struct counter_device *counter,
250 			       struct counter_count *count,
251 			       enum counter_function *function)
252 {
253 	struct quad8 *const priv = counter_priv(counter);
254 	unsigned long irqflags;
255 	int retval;
256 
257 	spin_lock_irqsave(&priv->lock, irqflags);
258 
259 	retval = quad8_function_get(priv, count->id, function);
260 
261 	spin_unlock_irqrestore(&priv->lock, irqflags);
262 
263 	return retval;
264 }
265 
266 static int quad8_function_write(struct counter_device *counter,
267 				struct counter_count *count,
268 				enum counter_function function)
269 {
270 	struct quad8 *const priv = counter_priv(counter);
271 	const int id = count->id;
272 	unsigned int *const quadrature_mode = priv->quadrature_mode + id;
273 	unsigned int *const scale = priv->quadrature_scale + id;
274 	unsigned int *const synchronous_mode = priv->synchronous_mode + id;
275 	u8 __iomem *const control = &priv->reg->channel[id].control;
276 	unsigned long irqflags;
277 	unsigned int mode_cfg;
278 	unsigned int idr_cfg;
279 
280 	spin_lock_irqsave(&priv->lock, irqflags);
281 
282 	mode_cfg = priv->count_mode[id] << 1;
283 	idr_cfg = priv->index_polarity[id] << 1;
284 
285 	if (function == COUNTER_FUNCTION_PULSE_DIRECTION) {
286 		*quadrature_mode = 0;
287 
288 		/* Quadrature scaling only available in quadrature mode */
289 		*scale = 0;
290 
291 		/* Synchronous function not supported in non-quadrature mode */
292 		if (*synchronous_mode) {
293 			*synchronous_mode = 0;
294 			/* Disable synchronous function mode */
295 			iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
296 		}
297 	} else {
298 		*quadrature_mode = 1;
299 
300 		switch (function) {
301 		case COUNTER_FUNCTION_QUADRATURE_X1_A:
302 			*scale = 0;
303 			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
304 			break;
305 		case COUNTER_FUNCTION_QUADRATURE_X2_A:
306 			*scale = 1;
307 			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
308 			break;
309 		case COUNTER_FUNCTION_QUADRATURE_X4:
310 			*scale = 2;
311 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
312 			break;
313 		default:
314 			/* should never reach this path */
315 			spin_unlock_irqrestore(&priv->lock, irqflags);
316 			return -EINVAL;
317 		}
318 	}
319 
320 	/* Load mode configuration to Counter Mode Register */
321 	iowrite8(QUAD8_CTR_CMR | mode_cfg, control);
322 
323 	spin_unlock_irqrestore(&priv->lock, irqflags);
324 
325 	return 0;
326 }
327 
328 static int quad8_direction_read(struct counter_device *counter,
329 				struct counter_count *count,
330 				enum counter_count_direction *direction)
331 {
332 	const struct quad8 *const priv = counter_priv(counter);
333 	unsigned int ud_flag;
334 	u8 __iomem *const flag_addr = &priv->reg->channel[count->id].control;
335 
336 	/* U/D flag: nonzero = up, zero = down */
337 	ud_flag = ioread8(flag_addr) & QUAD8_FLAG_UD;
338 
339 	*direction = (ud_flag) ? COUNTER_COUNT_DIRECTION_FORWARD :
340 		COUNTER_COUNT_DIRECTION_BACKWARD;
341 
342 	return 0;
343 }
344 
345 static const enum counter_synapse_action quad8_index_actions_list[] = {
346 	COUNTER_SYNAPSE_ACTION_NONE,
347 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
348 };
349 
350 static const enum counter_synapse_action quad8_synapse_actions_list[] = {
351 	COUNTER_SYNAPSE_ACTION_NONE,
352 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
353 	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
354 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
355 };
356 
357 static int quad8_action_read(struct counter_device *counter,
358 			     struct counter_count *count,
359 			     struct counter_synapse *synapse,
360 			     enum counter_synapse_action *action)
361 {
362 	struct quad8 *const priv = counter_priv(counter);
363 	unsigned long irqflags;
364 	int err;
365 	enum counter_function function;
366 	const size_t signal_a_id = count->synapses[0].signal->id;
367 	enum counter_count_direction direction;
368 
369 	/* Handle Index signals */
370 	if (synapse->signal->id >= 16) {
371 		if (!priv->preset_enable[count->id])
372 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
373 		else
374 			*action = COUNTER_SYNAPSE_ACTION_NONE;
375 
376 		return 0;
377 	}
378 
379 	spin_lock_irqsave(&priv->lock, irqflags);
380 
381 	/* Get Count function and direction atomically */
382 	err = quad8_function_get(priv, count->id, &function);
383 	if (err) {
384 		spin_unlock_irqrestore(&priv->lock, irqflags);
385 		return err;
386 	}
387 	err = quad8_direction_read(counter, count, &direction);
388 	if (err) {
389 		spin_unlock_irqrestore(&priv->lock, irqflags);
390 		return err;
391 	}
392 
393 	spin_unlock_irqrestore(&priv->lock, irqflags);
394 
395 	/* Default action mode */
396 	*action = COUNTER_SYNAPSE_ACTION_NONE;
397 
398 	/* Determine action mode based on current count function mode */
399 	switch (function) {
400 	case COUNTER_FUNCTION_PULSE_DIRECTION:
401 		if (synapse->signal->id == signal_a_id)
402 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
403 		return 0;
404 	case COUNTER_FUNCTION_QUADRATURE_X1_A:
405 		if (synapse->signal->id == signal_a_id) {
406 			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
407 				*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
408 			else
409 				*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
410 		}
411 		return 0;
412 	case COUNTER_FUNCTION_QUADRATURE_X2_A:
413 		if (synapse->signal->id == signal_a_id)
414 			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
415 		return 0;
416 	case COUNTER_FUNCTION_QUADRATURE_X4:
417 		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
418 		return 0;
419 	default:
420 		/* should never reach this path */
421 		return -EINVAL;
422 	}
423 }
424 
425 enum {
426 	QUAD8_EVENT_CARRY = 0,
427 	QUAD8_EVENT_COMPARE = 1,
428 	QUAD8_EVENT_CARRY_BORROW = 2,
429 	QUAD8_EVENT_INDEX = 3,
430 };
431 
432 static int quad8_events_configure(struct counter_device *counter)
433 {
434 	struct quad8 *const priv = counter_priv(counter);
435 	unsigned long irq_enabled = 0;
436 	unsigned long irqflags;
437 	struct counter_event_node *event_node;
438 	unsigned int next_irq_trigger;
439 	unsigned long ior_cfg;
440 
441 	spin_lock_irqsave(&priv->lock, irqflags);
442 
443 	list_for_each_entry(event_node, &counter->events_list, l) {
444 		switch (event_node->event) {
445 		case COUNTER_EVENT_OVERFLOW:
446 			next_irq_trigger = QUAD8_EVENT_CARRY;
447 			break;
448 		case COUNTER_EVENT_THRESHOLD:
449 			next_irq_trigger = QUAD8_EVENT_COMPARE;
450 			break;
451 		case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
452 			next_irq_trigger = QUAD8_EVENT_CARRY_BORROW;
453 			break;
454 		case COUNTER_EVENT_INDEX:
455 			next_irq_trigger = QUAD8_EVENT_INDEX;
456 			break;
457 		default:
458 			/* should never reach this path */
459 			spin_unlock_irqrestore(&priv->lock, irqflags);
460 			return -EINVAL;
461 		}
462 
463 		/* Enable IRQ line */
464 		irq_enabled |= BIT(event_node->channel);
465 
466 		/* Skip configuration if it is the same as previously set */
467 		if (priv->irq_trigger[event_node->channel] == next_irq_trigger)
468 			continue;
469 
470 		/* Save new IRQ function configuration */
471 		priv->irq_trigger[event_node->channel] = next_irq_trigger;
472 
473 		/* Load configuration to I/O Control Register */
474 		ior_cfg = priv->ab_enable[event_node->channel] |
475 			  priv->preset_enable[event_node->channel] << 1 |
476 			  priv->irq_trigger[event_node->channel] << 3;
477 		iowrite8(QUAD8_CTR_IOR | ior_cfg,
478 			 &priv->reg->channel[event_node->channel].control);
479 	}
480 
481 	iowrite8(irq_enabled, &priv->reg->index_interrupt);
482 
483 	spin_unlock_irqrestore(&priv->lock, irqflags);
484 
485 	return 0;
486 }
487 
488 static int quad8_watch_validate(struct counter_device *counter,
489 				const struct counter_watch *watch)
490 {
491 	struct counter_event_node *event_node;
492 
493 	if (watch->channel > QUAD8_NUM_COUNTERS - 1)
494 		return -EINVAL;
495 
496 	switch (watch->event) {
497 	case COUNTER_EVENT_OVERFLOW:
498 	case COUNTER_EVENT_THRESHOLD:
499 	case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
500 	case COUNTER_EVENT_INDEX:
501 		list_for_each_entry(event_node, &counter->next_events_list, l)
502 			if (watch->channel == event_node->channel &&
503 				watch->event != event_node->event)
504 				return -EINVAL;
505 		return 0;
506 	default:
507 		return -EINVAL;
508 	}
509 }
510 
511 static const struct counter_ops quad8_ops = {
512 	.signal_read = quad8_signal_read,
513 	.count_read = quad8_count_read,
514 	.count_write = quad8_count_write,
515 	.function_read = quad8_function_read,
516 	.function_write = quad8_function_write,
517 	.action_read = quad8_action_read,
518 	.events_configure = quad8_events_configure,
519 	.watch_validate = quad8_watch_validate,
520 };
521 
522 static const char *const quad8_index_polarity_modes[] = {
523 	"negative",
524 	"positive"
525 };
526 
527 static int quad8_index_polarity_get(struct counter_device *counter,
528 				    struct counter_signal *signal,
529 				    u32 *index_polarity)
530 {
531 	const struct quad8 *const priv = counter_priv(counter);
532 	const size_t channel_id = signal->id - 16;
533 
534 	*index_polarity = priv->index_polarity[channel_id];
535 
536 	return 0;
537 }
538 
539 static int quad8_index_polarity_set(struct counter_device *counter,
540 				    struct counter_signal *signal,
541 				    u32 index_polarity)
542 {
543 	struct quad8 *const priv = counter_priv(counter);
544 	const size_t channel_id = signal->id - 16;
545 	u8 __iomem *const control = &priv->reg->channel[channel_id].control;
546 	unsigned long irqflags;
547 	unsigned int idr_cfg = index_polarity << 1;
548 
549 	spin_lock_irqsave(&priv->lock, irqflags);
550 
551 	idr_cfg |= priv->synchronous_mode[channel_id];
552 
553 	priv->index_polarity[channel_id] = index_polarity;
554 
555 	/* Load Index Control configuration to Index Control Register */
556 	iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
557 
558 	spin_unlock_irqrestore(&priv->lock, irqflags);
559 
560 	return 0;
561 }
562 
563 static int quad8_polarity_read(struct counter_device *counter,
564 			       struct counter_signal *signal,
565 			       enum counter_signal_polarity *polarity)
566 {
567 	int err;
568 	u32 index_polarity;
569 
570 	err = quad8_index_polarity_get(counter, signal, &index_polarity);
571 	if (err)
572 		return err;
573 
574 	*polarity = (index_polarity) ? COUNTER_SIGNAL_POLARITY_POSITIVE :
575 		COUNTER_SIGNAL_POLARITY_NEGATIVE;
576 
577 	return 0;
578 }
579 
580 static int quad8_polarity_write(struct counter_device *counter,
581 				struct counter_signal *signal,
582 				enum counter_signal_polarity polarity)
583 {
584 	const u32 pol = (polarity == COUNTER_SIGNAL_POLARITY_POSITIVE) ? 1 : 0;
585 
586 	return quad8_index_polarity_set(counter, signal, pol);
587 }
588 
589 static const char *const quad8_synchronous_modes[] = {
590 	"non-synchronous",
591 	"synchronous"
592 };
593 
594 static int quad8_synchronous_mode_get(struct counter_device *counter,
595 				      struct counter_signal *signal,
596 				      u32 *synchronous_mode)
597 {
598 	const struct quad8 *const priv = counter_priv(counter);
599 	const size_t channel_id = signal->id - 16;
600 
601 	*synchronous_mode = priv->synchronous_mode[channel_id];
602 
603 	return 0;
604 }
605 
606 static int quad8_synchronous_mode_set(struct counter_device *counter,
607 				      struct counter_signal *signal,
608 				      u32 synchronous_mode)
609 {
610 	struct quad8 *const priv = counter_priv(counter);
611 	const size_t channel_id = signal->id - 16;
612 	u8 __iomem *const control = &priv->reg->channel[channel_id].control;
613 	unsigned long irqflags;
614 	unsigned int idr_cfg = synchronous_mode;
615 
616 	spin_lock_irqsave(&priv->lock, irqflags);
617 
618 	idr_cfg |= priv->index_polarity[channel_id] << 1;
619 
620 	/* Index function must be non-synchronous in non-quadrature mode */
621 	if (synchronous_mode && !priv->quadrature_mode[channel_id]) {
622 		spin_unlock_irqrestore(&priv->lock, irqflags);
623 		return -EINVAL;
624 	}
625 
626 	priv->synchronous_mode[channel_id] = synchronous_mode;
627 
628 	/* Load Index Control configuration to Index Control Register */
629 	iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
630 
631 	spin_unlock_irqrestore(&priv->lock, irqflags);
632 
633 	return 0;
634 }
635 
636 static int quad8_count_floor_read(struct counter_device *counter,
637 				  struct counter_count *count, u64 *floor)
638 {
639 	/* Only a floor of 0 is supported */
640 	*floor = 0;
641 
642 	return 0;
643 }
644 
645 static int quad8_count_mode_read(struct counter_device *counter,
646 				 struct counter_count *count,
647 				 enum counter_count_mode *cnt_mode)
648 {
649 	const struct quad8 *const priv = counter_priv(counter);
650 
651 	/* Map 104-QUAD-8 count mode to Generic Counter count mode */
652 	switch (priv->count_mode[count->id]) {
653 	case 0:
654 		*cnt_mode = COUNTER_COUNT_MODE_NORMAL;
655 		break;
656 	case 1:
657 		*cnt_mode = COUNTER_COUNT_MODE_RANGE_LIMIT;
658 		break;
659 	case 2:
660 		*cnt_mode = COUNTER_COUNT_MODE_NON_RECYCLE;
661 		break;
662 	case 3:
663 		*cnt_mode = COUNTER_COUNT_MODE_MODULO_N;
664 		break;
665 	}
666 
667 	return 0;
668 }
669 
670 static int quad8_count_mode_write(struct counter_device *counter,
671 				  struct counter_count *count,
672 				  enum counter_count_mode cnt_mode)
673 {
674 	struct quad8 *const priv = counter_priv(counter);
675 	unsigned int count_mode;
676 	unsigned int mode_cfg;
677 	u8 __iomem *const control = &priv->reg->channel[count->id].control;
678 	unsigned long irqflags;
679 
680 	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
681 	switch (cnt_mode) {
682 	case COUNTER_COUNT_MODE_NORMAL:
683 		count_mode = 0;
684 		break;
685 	case COUNTER_COUNT_MODE_RANGE_LIMIT:
686 		count_mode = 1;
687 		break;
688 	case COUNTER_COUNT_MODE_NON_RECYCLE:
689 		count_mode = 2;
690 		break;
691 	case COUNTER_COUNT_MODE_MODULO_N:
692 		count_mode = 3;
693 		break;
694 	default:
695 		/* should never reach this path */
696 		return -EINVAL;
697 	}
698 
699 	spin_lock_irqsave(&priv->lock, irqflags);
700 
701 	priv->count_mode[count->id] = count_mode;
702 
703 	/* Set count mode configuration value */
704 	mode_cfg = count_mode << 1;
705 
706 	/* Add quadrature mode configuration */
707 	if (priv->quadrature_mode[count->id])
708 		mode_cfg |= (priv->quadrature_scale[count->id] + 1) << 3;
709 
710 	/* Load mode configuration to Counter Mode Register */
711 	iowrite8(QUAD8_CTR_CMR | mode_cfg, control);
712 
713 	spin_unlock_irqrestore(&priv->lock, irqflags);
714 
715 	return 0;
716 }
717 
718 static int quad8_count_enable_read(struct counter_device *counter,
719 				   struct counter_count *count, u8 *enable)
720 {
721 	const struct quad8 *const priv = counter_priv(counter);
722 
723 	*enable = priv->ab_enable[count->id];
724 
725 	return 0;
726 }
727 
728 static int quad8_count_enable_write(struct counter_device *counter,
729 				    struct counter_count *count, u8 enable)
730 {
731 	struct quad8 *const priv = counter_priv(counter);
732 	u8 __iomem *const control = &priv->reg->channel[count->id].control;
733 	unsigned long irqflags;
734 	unsigned int ior_cfg;
735 
736 	spin_lock_irqsave(&priv->lock, irqflags);
737 
738 	priv->ab_enable[count->id] = enable;
739 
740 	ior_cfg = enable | priv->preset_enable[count->id] << 1 |
741 		  priv->irq_trigger[count->id] << 3;
742 
743 	/* Load I/O control configuration */
744 	iowrite8(QUAD8_CTR_IOR | ior_cfg, control);
745 
746 	spin_unlock_irqrestore(&priv->lock, irqflags);
747 
748 	return 0;
749 }
750 
751 static const char *const quad8_noise_error_states[] = {
752 	"No excessive noise is present at the count inputs",
753 	"Excessive noise is present at the count inputs"
754 };
755 
756 static int quad8_error_noise_get(struct counter_device *counter,
757 				 struct counter_count *count, u32 *noise_error)
758 {
759 	const struct quad8 *const priv = counter_priv(counter);
760 	u8 __iomem *const flag_addr = &priv->reg->channel[count->id].control;
761 
762 	*noise_error = !!(ioread8(flag_addr) & QUAD8_FLAG_E);
763 
764 	return 0;
765 }
766 
767 static int quad8_count_preset_read(struct counter_device *counter,
768 				   struct counter_count *count, u64 *preset)
769 {
770 	const struct quad8 *const priv = counter_priv(counter);
771 
772 	*preset = priv->preset[count->id];
773 
774 	return 0;
775 }
776 
777 static void quad8_preset_register_set(struct quad8 *const priv, const int id,
778 				      const unsigned int preset)
779 {
780 	struct channel_reg __iomem *const chan = priv->reg->channel + id;
781 	int i;
782 
783 	priv->preset[id] = preset;
784 
785 	/* Reset Byte Pointer */
786 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
787 
788 	/* Set Preset Register */
789 	for (i = 0; i < 3; i++)
790 		iowrite8(preset >> (8 * i), &chan->data);
791 }
792 
793 static int quad8_count_preset_write(struct counter_device *counter,
794 				    struct counter_count *count, u64 preset)
795 {
796 	struct quad8 *const priv = counter_priv(counter);
797 	unsigned long irqflags;
798 
799 	if (preset > LS7267_CNTR_MAX)
800 		return -ERANGE;
801 
802 	spin_lock_irqsave(&priv->lock, irqflags);
803 
804 	quad8_preset_register_set(priv, count->id, preset);
805 
806 	spin_unlock_irqrestore(&priv->lock, irqflags);
807 
808 	return 0;
809 }
810 
811 static int quad8_count_ceiling_read(struct counter_device *counter,
812 				    struct counter_count *count, u64 *ceiling)
813 {
814 	struct quad8 *const priv = counter_priv(counter);
815 	unsigned long irqflags;
816 
817 	spin_lock_irqsave(&priv->lock, irqflags);
818 
819 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
820 	switch (priv->count_mode[count->id]) {
821 	case 1:
822 	case 3:
823 		*ceiling = priv->preset[count->id];
824 		break;
825 	default:
826 		*ceiling = LS7267_CNTR_MAX;
827 		break;
828 	}
829 
830 	spin_unlock_irqrestore(&priv->lock, irqflags);
831 
832 	return 0;
833 }
834 
835 static int quad8_count_ceiling_write(struct counter_device *counter,
836 				     struct counter_count *count, u64 ceiling)
837 {
838 	struct quad8 *const priv = counter_priv(counter);
839 	unsigned long irqflags;
840 
841 	if (ceiling > LS7267_CNTR_MAX)
842 		return -ERANGE;
843 
844 	spin_lock_irqsave(&priv->lock, irqflags);
845 
846 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
847 	switch (priv->count_mode[count->id]) {
848 	case 1:
849 	case 3:
850 		quad8_preset_register_set(priv, count->id, ceiling);
851 		spin_unlock_irqrestore(&priv->lock, irqflags);
852 		return 0;
853 	}
854 
855 	spin_unlock_irqrestore(&priv->lock, irqflags);
856 
857 	return -EINVAL;
858 }
859 
860 static int quad8_count_preset_enable_read(struct counter_device *counter,
861 					  struct counter_count *count,
862 					  u8 *preset_enable)
863 {
864 	const struct quad8 *const priv = counter_priv(counter);
865 
866 	*preset_enable = !priv->preset_enable[count->id];
867 
868 	return 0;
869 }
870 
871 static int quad8_count_preset_enable_write(struct counter_device *counter,
872 					   struct counter_count *count,
873 					   u8 preset_enable)
874 {
875 	struct quad8 *const priv = counter_priv(counter);
876 	u8 __iomem *const control = &priv->reg->channel[count->id].control;
877 	unsigned long irqflags;
878 	unsigned int ior_cfg;
879 
880 	/* Preset enable is active low in Input/Output Control register */
881 	preset_enable = !preset_enable;
882 
883 	spin_lock_irqsave(&priv->lock, irqflags);
884 
885 	priv->preset_enable[count->id] = preset_enable;
886 
887 	ior_cfg = priv->ab_enable[count->id] | preset_enable << 1 |
888 		  priv->irq_trigger[count->id] << 3;
889 
890 	/* Load I/O control configuration to Input / Output Control Register */
891 	iowrite8(QUAD8_CTR_IOR | ior_cfg, control);
892 
893 	spin_unlock_irqrestore(&priv->lock, irqflags);
894 
895 	return 0;
896 }
897 
898 static int quad8_signal_cable_fault_read(struct counter_device *counter,
899 					 struct counter_signal *signal,
900 					 u8 *cable_fault)
901 {
902 	struct quad8 *const priv = counter_priv(counter);
903 	const size_t channel_id = signal->id / 2;
904 	unsigned long irqflags;
905 	bool disabled;
906 	unsigned int status;
907 
908 	spin_lock_irqsave(&priv->lock, irqflags);
909 
910 	disabled = !(priv->cable_fault_enable & BIT(channel_id));
911 
912 	if (disabled) {
913 		spin_unlock_irqrestore(&priv->lock, irqflags);
914 		return -EINVAL;
915 	}
916 
917 	/* Logic 0 = cable fault */
918 	status = ioread8(&priv->reg->cable_status);
919 
920 	spin_unlock_irqrestore(&priv->lock, irqflags);
921 
922 	/* Mask respective channel and invert logic */
923 	*cable_fault = !(status & BIT(channel_id));
924 
925 	return 0;
926 }
927 
928 static int quad8_signal_cable_fault_enable_read(struct counter_device *counter,
929 						struct counter_signal *signal,
930 						u8 *enable)
931 {
932 	const struct quad8 *const priv = counter_priv(counter);
933 	const size_t channel_id = signal->id / 2;
934 
935 	*enable = !!(priv->cable_fault_enable & BIT(channel_id));
936 
937 	return 0;
938 }
939 
940 static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
941 						 struct counter_signal *signal,
942 						 u8 enable)
943 {
944 	struct quad8 *const priv = counter_priv(counter);
945 	const size_t channel_id = signal->id / 2;
946 	unsigned long irqflags;
947 	unsigned int cable_fault_enable;
948 
949 	spin_lock_irqsave(&priv->lock, irqflags);
950 
951 	if (enable)
952 		priv->cable_fault_enable |= BIT(channel_id);
953 	else
954 		priv->cable_fault_enable &= ~BIT(channel_id);
955 
956 	/* Enable is active low in Differential Encoder Cable Status register */
957 	cable_fault_enable = ~priv->cable_fault_enable;
958 
959 	iowrite8(cable_fault_enable, &priv->reg->cable_status);
960 
961 	spin_unlock_irqrestore(&priv->lock, irqflags);
962 
963 	return 0;
964 }
965 
966 static int quad8_signal_fck_prescaler_read(struct counter_device *counter,
967 					   struct counter_signal *signal,
968 					   u8 *prescaler)
969 {
970 	const struct quad8 *const priv = counter_priv(counter);
971 
972 	*prescaler = priv->fck_prescaler[signal->id / 2];
973 
974 	return 0;
975 }
976 
977 static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
978 					    struct counter_signal *signal,
979 					    u8 prescaler)
980 {
981 	struct quad8 *const priv = counter_priv(counter);
982 	const size_t channel_id = signal->id / 2;
983 	struct channel_reg __iomem *const chan = priv->reg->channel + channel_id;
984 	unsigned long irqflags;
985 
986 	spin_lock_irqsave(&priv->lock, irqflags);
987 
988 	priv->fck_prescaler[channel_id] = prescaler;
989 
990 	/* Reset Byte Pointer */
991 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
992 
993 	/* Set filter clock factor */
994 	iowrite8(prescaler, &chan->data);
995 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
996 		 &chan->control);
997 
998 	spin_unlock_irqrestore(&priv->lock, irqflags);
999 
1000 	return 0;
1001 }
1002 
1003 static struct counter_comp quad8_signal_ext[] = {
1004 	COUNTER_COMP_SIGNAL_BOOL("cable_fault", quad8_signal_cable_fault_read,
1005 				 NULL),
1006 	COUNTER_COMP_SIGNAL_BOOL("cable_fault_enable",
1007 				 quad8_signal_cable_fault_enable_read,
1008 				 quad8_signal_cable_fault_enable_write),
1009 	COUNTER_COMP_SIGNAL_U8("filter_clock_prescaler",
1010 			       quad8_signal_fck_prescaler_read,
1011 			       quad8_signal_fck_prescaler_write)
1012 };
1013 
1014 static const enum counter_signal_polarity quad8_polarities[] = {
1015 	COUNTER_SIGNAL_POLARITY_POSITIVE,
1016 	COUNTER_SIGNAL_POLARITY_NEGATIVE,
1017 };
1018 
1019 static DEFINE_COUNTER_AVAILABLE(quad8_polarity_available, quad8_polarities);
1020 
1021 static DEFINE_COUNTER_ENUM(quad8_index_pol_enum, quad8_index_polarity_modes);
1022 static DEFINE_COUNTER_ENUM(quad8_synch_mode_enum, quad8_synchronous_modes);
1023 
1024 static struct counter_comp quad8_index_ext[] = {
1025 	COUNTER_COMP_SIGNAL_ENUM("index_polarity", quad8_index_polarity_get,
1026 				 quad8_index_polarity_set,
1027 				 quad8_index_pol_enum),
1028 	COUNTER_COMP_POLARITY(quad8_polarity_read, quad8_polarity_write,
1029 			      quad8_polarity_available),
1030 	COUNTER_COMP_SIGNAL_ENUM("synchronous_mode", quad8_synchronous_mode_get,
1031 				 quad8_synchronous_mode_set,
1032 				 quad8_synch_mode_enum),
1033 };
1034 
1035 #define QUAD8_QUAD_SIGNAL(_id, _name) {		\
1036 	.id = (_id),				\
1037 	.name = (_name),			\
1038 	.ext = quad8_signal_ext,		\
1039 	.num_ext = ARRAY_SIZE(quad8_signal_ext)	\
1040 }
1041 
1042 #define	QUAD8_INDEX_SIGNAL(_id, _name) {	\
1043 	.id = (_id),				\
1044 	.name = (_name),			\
1045 	.ext = quad8_index_ext,			\
1046 	.num_ext = ARRAY_SIZE(quad8_index_ext)	\
1047 }
1048 
1049 static struct counter_signal quad8_signals[] = {
1050 	QUAD8_QUAD_SIGNAL(0, "Channel 1 Quadrature A"),
1051 	QUAD8_QUAD_SIGNAL(1, "Channel 1 Quadrature B"),
1052 	QUAD8_QUAD_SIGNAL(2, "Channel 2 Quadrature A"),
1053 	QUAD8_QUAD_SIGNAL(3, "Channel 2 Quadrature B"),
1054 	QUAD8_QUAD_SIGNAL(4, "Channel 3 Quadrature A"),
1055 	QUAD8_QUAD_SIGNAL(5, "Channel 3 Quadrature B"),
1056 	QUAD8_QUAD_SIGNAL(6, "Channel 4 Quadrature A"),
1057 	QUAD8_QUAD_SIGNAL(7, "Channel 4 Quadrature B"),
1058 	QUAD8_QUAD_SIGNAL(8, "Channel 5 Quadrature A"),
1059 	QUAD8_QUAD_SIGNAL(9, "Channel 5 Quadrature B"),
1060 	QUAD8_QUAD_SIGNAL(10, "Channel 6 Quadrature A"),
1061 	QUAD8_QUAD_SIGNAL(11, "Channel 6 Quadrature B"),
1062 	QUAD8_QUAD_SIGNAL(12, "Channel 7 Quadrature A"),
1063 	QUAD8_QUAD_SIGNAL(13, "Channel 7 Quadrature B"),
1064 	QUAD8_QUAD_SIGNAL(14, "Channel 8 Quadrature A"),
1065 	QUAD8_QUAD_SIGNAL(15, "Channel 8 Quadrature B"),
1066 	QUAD8_INDEX_SIGNAL(16, "Channel 1 Index"),
1067 	QUAD8_INDEX_SIGNAL(17, "Channel 2 Index"),
1068 	QUAD8_INDEX_SIGNAL(18, "Channel 3 Index"),
1069 	QUAD8_INDEX_SIGNAL(19, "Channel 4 Index"),
1070 	QUAD8_INDEX_SIGNAL(20, "Channel 5 Index"),
1071 	QUAD8_INDEX_SIGNAL(21, "Channel 6 Index"),
1072 	QUAD8_INDEX_SIGNAL(22, "Channel 7 Index"),
1073 	QUAD8_INDEX_SIGNAL(23, "Channel 8 Index")
1074 };
1075 
1076 #define QUAD8_COUNT_SYNAPSES(_id) {					\
1077 	{								\
1078 		.actions_list = quad8_synapse_actions_list,		\
1079 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1080 		.signal = quad8_signals + 2 * (_id)			\
1081 	},								\
1082 	{								\
1083 		.actions_list = quad8_synapse_actions_list,		\
1084 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1085 		.signal = quad8_signals + 2 * (_id) + 1			\
1086 	},								\
1087 	{								\
1088 		.actions_list = quad8_index_actions_list,		\
1089 		.num_actions = ARRAY_SIZE(quad8_index_actions_list),	\
1090 		.signal = quad8_signals + 2 * (_id) + 16		\
1091 	}								\
1092 }
1093 
1094 static struct counter_synapse quad8_count_synapses[][3] = {
1095 	QUAD8_COUNT_SYNAPSES(0), QUAD8_COUNT_SYNAPSES(1),
1096 	QUAD8_COUNT_SYNAPSES(2), QUAD8_COUNT_SYNAPSES(3),
1097 	QUAD8_COUNT_SYNAPSES(4), QUAD8_COUNT_SYNAPSES(5),
1098 	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
1099 };
1100 
1101 static const enum counter_count_mode quad8_cnt_modes[] = {
1102 	COUNTER_COUNT_MODE_NORMAL,
1103 	COUNTER_COUNT_MODE_RANGE_LIMIT,
1104 	COUNTER_COUNT_MODE_NON_RECYCLE,
1105 	COUNTER_COUNT_MODE_MODULO_N,
1106 };
1107 
1108 static DEFINE_COUNTER_AVAILABLE(quad8_count_mode_available, quad8_cnt_modes);
1109 
1110 static DEFINE_COUNTER_ENUM(quad8_error_noise_enum, quad8_noise_error_states);
1111 
1112 static struct counter_comp quad8_count_ext[] = {
1113 	COUNTER_COMP_CEILING(quad8_count_ceiling_read,
1114 			     quad8_count_ceiling_write),
1115 	COUNTER_COMP_FLOOR(quad8_count_floor_read, NULL),
1116 	COUNTER_COMP_COUNT_MODE(quad8_count_mode_read, quad8_count_mode_write,
1117 				quad8_count_mode_available),
1118 	COUNTER_COMP_DIRECTION(quad8_direction_read),
1119 	COUNTER_COMP_ENABLE(quad8_count_enable_read, quad8_count_enable_write),
1120 	COUNTER_COMP_COUNT_ENUM("error_noise", quad8_error_noise_get, NULL,
1121 				quad8_error_noise_enum),
1122 	COUNTER_COMP_PRESET(quad8_count_preset_read, quad8_count_preset_write),
1123 	COUNTER_COMP_PRESET_ENABLE(quad8_count_preset_enable_read,
1124 				   quad8_count_preset_enable_write),
1125 };
1126 
1127 #define QUAD8_COUNT(_id, _cntname) {					\
1128 	.id = (_id),							\
1129 	.name = (_cntname),						\
1130 	.functions_list = quad8_count_functions_list,			\
1131 	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
1132 	.synapses = quad8_count_synapses[(_id)],			\
1133 	.num_synapses =	2,						\
1134 	.ext = quad8_count_ext,						\
1135 	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
1136 }
1137 
1138 static struct counter_count quad8_counts[] = {
1139 	QUAD8_COUNT(0, "Channel 1 Count"),
1140 	QUAD8_COUNT(1, "Channel 2 Count"),
1141 	QUAD8_COUNT(2, "Channel 3 Count"),
1142 	QUAD8_COUNT(3, "Channel 4 Count"),
1143 	QUAD8_COUNT(4, "Channel 5 Count"),
1144 	QUAD8_COUNT(5, "Channel 6 Count"),
1145 	QUAD8_COUNT(6, "Channel 7 Count"),
1146 	QUAD8_COUNT(7, "Channel 8 Count")
1147 };
1148 
1149 static irqreturn_t quad8_irq_handler(int irq, void *private)
1150 {
1151 	struct counter_device *counter = private;
1152 	struct quad8 *const priv = counter_priv(counter);
1153 	unsigned long irq_status;
1154 	unsigned long channel;
1155 	u8 event;
1156 
1157 	irq_status = ioread8(&priv->reg->interrupt_status);
1158 	if (!irq_status)
1159 		return IRQ_NONE;
1160 
1161 	for_each_set_bit(channel, &irq_status, QUAD8_NUM_COUNTERS) {
1162 		switch (priv->irq_trigger[channel]) {
1163 		case QUAD8_EVENT_CARRY:
1164 			event = COUNTER_EVENT_OVERFLOW;
1165 				break;
1166 		case QUAD8_EVENT_COMPARE:
1167 			event = COUNTER_EVENT_THRESHOLD;
1168 				break;
1169 		case QUAD8_EVENT_CARRY_BORROW:
1170 			event = COUNTER_EVENT_OVERFLOW_UNDERFLOW;
1171 				break;
1172 		case QUAD8_EVENT_INDEX:
1173 			event = COUNTER_EVENT_INDEX;
1174 				break;
1175 		default:
1176 			/* should never reach this path */
1177 			WARN_ONCE(true, "invalid interrupt trigger function %u configured for channel %lu\n",
1178 				  priv->irq_trigger[channel], channel);
1179 			continue;
1180 		}
1181 
1182 		counter_push_event(counter, event, channel);
1183 	}
1184 
1185 	/* Clear pending interrupts on device */
1186 	iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, &priv->reg->channel_oper);
1187 
1188 	return IRQ_HANDLED;
1189 }
1190 
1191 static void quad8_init_counter(struct channel_reg __iomem *const chan)
1192 {
1193 	unsigned long i;
1194 
1195 	/* Reset Byte Pointer */
1196 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
1197 	/* Reset filter clock factor */
1198 	iowrite8(0, &chan->data);
1199 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
1200 		 &chan->control);
1201 	/* Reset Byte Pointer */
1202 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
1203 	/* Reset Preset Register */
1204 	for (i = 0; i < 3; i++)
1205 		iowrite8(0x00, &chan->data);
1206 	/* Reset Borrow, Carry, Compare, and Sign flags */
1207 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, &chan->control);
1208 	/* Reset Error flag */
1209 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, &chan->control);
1210 	/* Binary encoding; Normal count; non-quadrature mode */
1211 	iowrite8(QUAD8_CTR_CMR, &chan->control);
1212 	/* Disable A and B inputs; preset on index; FLG1 as Carry */
1213 	iowrite8(QUAD8_CTR_IOR, &chan->control);
1214 	/* Disable index function; negative index polarity */
1215 	iowrite8(QUAD8_CTR_IDR, &chan->control);
1216 }
1217 
1218 static int quad8_probe(struct device *dev, unsigned int id)
1219 {
1220 	struct counter_device *counter;
1221 	struct quad8 *priv;
1222 	unsigned long i;
1223 	int err;
1224 
1225 	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
1226 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
1227 			base[id], base[id] + QUAD8_EXTENT);
1228 		return -EBUSY;
1229 	}
1230 
1231 	counter = devm_counter_alloc(dev, sizeof(*priv));
1232 	if (!counter)
1233 		return -ENOMEM;
1234 	priv = counter_priv(counter);
1235 
1236 	priv->reg = devm_ioport_map(dev, base[id], QUAD8_EXTENT);
1237 	if (!priv->reg)
1238 		return -ENOMEM;
1239 
1240 	/* Initialize Counter device and driver data */
1241 	counter->name = dev_name(dev);
1242 	counter->parent = dev;
1243 	counter->ops = &quad8_ops;
1244 	counter->counts = quad8_counts;
1245 	counter->num_counts = ARRAY_SIZE(quad8_counts);
1246 	counter->signals = quad8_signals;
1247 	counter->num_signals = ARRAY_SIZE(quad8_signals);
1248 
1249 	spin_lock_init(&priv->lock);
1250 
1251 	/* Reset Index/Interrupt Register */
1252 	iowrite8(0x00, &priv->reg->index_interrupt);
1253 	/* Reset all counters and disable interrupt function */
1254 	iowrite8(QUAD8_CHAN_OP_RESET_COUNTERS, &priv->reg->channel_oper);
1255 	/* Set initial configuration for all counters */
1256 	for (i = 0; i < QUAD8_NUM_COUNTERS; i++)
1257 		quad8_init_counter(priv->reg->channel + i);
1258 	/* Disable Differential Encoder Cable Status for all channels */
1259 	iowrite8(0xFF, &priv->reg->cable_status);
1260 	/* Enable all counters and enable interrupt function */
1261 	iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, &priv->reg->channel_oper);
1262 
1263 	err = devm_request_irq(&counter->dev, irq[id], quad8_irq_handler,
1264 			       IRQF_SHARED, counter->name, counter);
1265 	if (err)
1266 		return err;
1267 
1268 	err = devm_counter_add(dev, counter);
1269 	if (err < 0)
1270 		return dev_err_probe(dev, err, "Failed to add counter\n");
1271 
1272 	return 0;
1273 }
1274 
1275 static struct isa_driver quad8_driver = {
1276 	.probe = quad8_probe,
1277 	.driver = {
1278 		.name = "104-quad-8"
1279 	}
1280 };
1281 
1282 module_isa_driver_with_irq(quad8_driver, num_quad8, num_irq);
1283 
1284 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
1285 MODULE_DESCRIPTION("ACCES 104-QUAD-8 driver");
1286 MODULE_LICENSE("GPL v2");
1287 MODULE_IMPORT_NS(COUNTER);
1288