xref: /openbmc/linux/drivers/counter/104-quad-8.c (revision 5626af8f)
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 /* Borrow Toggle flip-flop */
101 #define QUAD8_FLAG_BT BIT(0)
102 /* Carry Toggle flip-flop */
103 #define QUAD8_FLAG_CT BIT(1)
104 /* Error flag */
105 #define QUAD8_FLAG_E BIT(4)
106 /* Up/Down flag */
107 #define QUAD8_FLAG_UD BIT(5)
108 /* Reset and Load Signal Decoders */
109 #define QUAD8_CTR_RLD 0x00
110 /* Counter Mode Register */
111 #define QUAD8_CTR_CMR 0x20
112 /* Input / Output Control Register */
113 #define QUAD8_CTR_IOR 0x40
114 /* Index Control Register */
115 #define QUAD8_CTR_IDR 0x60
116 /* Reset Byte Pointer (three byte data pointer) */
117 #define QUAD8_RLD_RESET_BP 0x01
118 /* Reset Counter */
119 #define QUAD8_RLD_RESET_CNTR 0x02
120 /* Reset Borrow Toggle, Carry Toggle, Compare Toggle, and Sign flags */
121 #define QUAD8_RLD_RESET_FLAGS 0x04
122 /* Reset Error flag */
123 #define QUAD8_RLD_RESET_E 0x06
124 /* Preset Register to Counter */
125 #define QUAD8_RLD_PRESET_CNTR 0x08
126 /* Transfer Counter to Output Latch */
127 #define QUAD8_RLD_CNTR_OUT 0x10
128 /* Transfer Preset Register LSB to FCK Prescaler */
129 #define QUAD8_RLD_PRESET_PSC 0x18
130 #define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
131 #define QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC 0x04
132 #define QUAD8_CMR_QUADRATURE_X1 0x08
133 #define QUAD8_CMR_QUADRATURE_X2 0x10
134 #define QUAD8_CMR_QUADRATURE_X4 0x18
135 
136 static int quad8_signal_read(struct counter_device *counter,
137 			     struct counter_signal *signal,
138 			     enum counter_signal_level *level)
139 {
140 	const struct quad8 *const priv = counter_priv(counter);
141 	unsigned int state;
142 
143 	/* Only Index signal levels can be read */
144 	if (signal->id < 16)
145 		return -EINVAL;
146 
147 	state = ioread8(&priv->reg->index_input_levels) & BIT(signal->id - 16);
148 
149 	*level = (state) ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
150 
151 	return 0;
152 }
153 
154 static int quad8_count_read(struct counter_device *counter,
155 			    struct counter_count *count, u64 *val)
156 {
157 	struct quad8 *const priv = counter_priv(counter);
158 	struct channel_reg __iomem *const chan = priv->reg->channel + count->id;
159 	unsigned int flags;
160 	unsigned int borrow;
161 	unsigned int carry;
162 	unsigned long irqflags;
163 	int i;
164 
165 	flags = ioread8(&chan->control);
166 	borrow = flags & QUAD8_FLAG_BT;
167 	carry = !!(flags & QUAD8_FLAG_CT);
168 
169 	/* Borrow XOR Carry effectively doubles count range */
170 	*val = (unsigned long)(borrow ^ carry) << 24;
171 
172 	spin_lock_irqsave(&priv->lock, irqflags);
173 
174 	/* Reset Byte Pointer; transfer Counter to Output Latch */
175 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
176 		 &chan->control);
177 
178 	for (i = 0; i < 3; i++)
179 		*val |= (unsigned long)ioread8(&chan->data) << (8 * i);
180 
181 	spin_unlock_irqrestore(&priv->lock, irqflags);
182 
183 	return 0;
184 }
185 
186 static int quad8_count_write(struct counter_device *counter,
187 			     struct counter_count *count, u64 val)
188 {
189 	struct quad8 *const priv = counter_priv(counter);
190 	struct channel_reg __iomem *const chan = priv->reg->channel + count->id;
191 	unsigned long irqflags;
192 	int i;
193 
194 	/* Only 24-bit values are supported */
195 	if (val > 0xFFFFFF)
196 		return -ERANGE;
197 
198 	spin_lock_irqsave(&priv->lock, irqflags);
199 
200 	/* Reset Byte Pointer */
201 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
202 
203 	/* Counter can only be set via Preset Register */
204 	for (i = 0; i < 3; i++)
205 		iowrite8(val >> (8 * i), &chan->data);
206 
207 	/* Transfer Preset Register to Counter */
208 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, &chan->control);
209 
210 	/* Reset Byte Pointer */
211 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
212 
213 	/* Set Preset Register back to original value */
214 	val = priv->preset[count->id];
215 	for (i = 0; i < 3; i++)
216 		iowrite8(val >> (8 * i), &chan->data);
217 
218 	/* Reset Borrow, Carry, Compare, and Sign flags */
219 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, &chan->control);
220 	/* Reset Error flag */
221 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, &chan->control);
222 
223 	spin_unlock_irqrestore(&priv->lock, irqflags);
224 
225 	return 0;
226 }
227 
228 static const enum counter_function quad8_count_functions_list[] = {
229 	COUNTER_FUNCTION_PULSE_DIRECTION,
230 	COUNTER_FUNCTION_QUADRATURE_X1_A,
231 	COUNTER_FUNCTION_QUADRATURE_X2_A,
232 	COUNTER_FUNCTION_QUADRATURE_X4,
233 };
234 
235 static int quad8_function_get(const struct quad8 *const priv, const size_t id,
236 			      enum counter_function *const function)
237 {
238 	if (!priv->quadrature_mode[id]) {
239 		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
240 		return 0;
241 	}
242 
243 	switch (priv->quadrature_scale[id]) {
244 	case 0:
245 		*function = COUNTER_FUNCTION_QUADRATURE_X1_A;
246 		return 0;
247 	case 1:
248 		*function = COUNTER_FUNCTION_QUADRATURE_X2_A;
249 		return 0;
250 	case 2:
251 		*function = COUNTER_FUNCTION_QUADRATURE_X4;
252 		return 0;
253 	default:
254 		/* should never reach this path */
255 		return -EINVAL;
256 	}
257 }
258 
259 static int quad8_function_read(struct counter_device *counter,
260 			       struct counter_count *count,
261 			       enum counter_function *function)
262 {
263 	struct quad8 *const priv = counter_priv(counter);
264 	unsigned long irqflags;
265 	int retval;
266 
267 	spin_lock_irqsave(&priv->lock, irqflags);
268 
269 	retval = quad8_function_get(priv, count->id, function);
270 
271 	spin_unlock_irqrestore(&priv->lock, irqflags);
272 
273 	return retval;
274 }
275 
276 static int quad8_function_write(struct counter_device *counter,
277 				struct counter_count *count,
278 				enum counter_function function)
279 {
280 	struct quad8 *const priv = counter_priv(counter);
281 	const int id = count->id;
282 	unsigned int *const quadrature_mode = priv->quadrature_mode + id;
283 	unsigned int *const scale = priv->quadrature_scale + id;
284 	unsigned int *const synchronous_mode = priv->synchronous_mode + id;
285 	u8 __iomem *const control = &priv->reg->channel[id].control;
286 	unsigned long irqflags;
287 	unsigned int mode_cfg;
288 	unsigned int idr_cfg;
289 
290 	spin_lock_irqsave(&priv->lock, irqflags);
291 
292 	mode_cfg = priv->count_mode[id] << 1;
293 	idr_cfg = priv->index_polarity[id] << 1;
294 
295 	if (function == COUNTER_FUNCTION_PULSE_DIRECTION) {
296 		*quadrature_mode = 0;
297 
298 		/* Quadrature scaling only available in quadrature mode */
299 		*scale = 0;
300 
301 		/* Synchronous function not supported in non-quadrature mode */
302 		if (*synchronous_mode) {
303 			*synchronous_mode = 0;
304 			/* Disable synchronous function mode */
305 			iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
306 		}
307 	} else {
308 		*quadrature_mode = 1;
309 
310 		switch (function) {
311 		case COUNTER_FUNCTION_QUADRATURE_X1_A:
312 			*scale = 0;
313 			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
314 			break;
315 		case COUNTER_FUNCTION_QUADRATURE_X2_A:
316 			*scale = 1;
317 			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
318 			break;
319 		case COUNTER_FUNCTION_QUADRATURE_X4:
320 			*scale = 2;
321 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
322 			break;
323 		default:
324 			/* should never reach this path */
325 			spin_unlock_irqrestore(&priv->lock, irqflags);
326 			return -EINVAL;
327 		}
328 	}
329 
330 	/* Load mode configuration to Counter Mode Register */
331 	iowrite8(QUAD8_CTR_CMR | mode_cfg, control);
332 
333 	spin_unlock_irqrestore(&priv->lock, irqflags);
334 
335 	return 0;
336 }
337 
338 static int quad8_direction_read(struct counter_device *counter,
339 				struct counter_count *count,
340 				enum counter_count_direction *direction)
341 {
342 	const struct quad8 *const priv = counter_priv(counter);
343 	unsigned int ud_flag;
344 	u8 __iomem *const flag_addr = &priv->reg->channel[count->id].control;
345 
346 	/* U/D flag: nonzero = up, zero = down */
347 	ud_flag = ioread8(flag_addr) & QUAD8_FLAG_UD;
348 
349 	*direction = (ud_flag) ? COUNTER_COUNT_DIRECTION_FORWARD :
350 		COUNTER_COUNT_DIRECTION_BACKWARD;
351 
352 	return 0;
353 }
354 
355 static const enum counter_synapse_action quad8_index_actions_list[] = {
356 	COUNTER_SYNAPSE_ACTION_NONE,
357 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
358 };
359 
360 static const enum counter_synapse_action quad8_synapse_actions_list[] = {
361 	COUNTER_SYNAPSE_ACTION_NONE,
362 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
363 	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
364 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
365 };
366 
367 static int quad8_action_read(struct counter_device *counter,
368 			     struct counter_count *count,
369 			     struct counter_synapse *synapse,
370 			     enum counter_synapse_action *action)
371 {
372 	struct quad8 *const priv = counter_priv(counter);
373 	unsigned long irqflags;
374 	int err;
375 	enum counter_function function;
376 	const size_t signal_a_id = count->synapses[0].signal->id;
377 	enum counter_count_direction direction;
378 
379 	/* Handle Index signals */
380 	if (synapse->signal->id >= 16) {
381 		if (priv->preset_enable[count->id])
382 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
383 		else
384 			*action = COUNTER_SYNAPSE_ACTION_NONE;
385 
386 		return 0;
387 	}
388 
389 	spin_lock_irqsave(&priv->lock, irqflags);
390 
391 	/* Get Count function and direction atomically */
392 	err = quad8_function_get(priv, count->id, &function);
393 	if (err) {
394 		spin_unlock_irqrestore(&priv->lock, irqflags);
395 		return err;
396 	}
397 	err = quad8_direction_read(counter, count, &direction);
398 	if (err) {
399 		spin_unlock_irqrestore(&priv->lock, irqflags);
400 		return err;
401 	}
402 
403 	spin_unlock_irqrestore(&priv->lock, irqflags);
404 
405 	/* Default action mode */
406 	*action = COUNTER_SYNAPSE_ACTION_NONE;
407 
408 	/* Determine action mode based on current count function mode */
409 	switch (function) {
410 	case COUNTER_FUNCTION_PULSE_DIRECTION:
411 		if (synapse->signal->id == signal_a_id)
412 			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
413 		return 0;
414 	case COUNTER_FUNCTION_QUADRATURE_X1_A:
415 		if (synapse->signal->id == signal_a_id) {
416 			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
417 				*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
418 			else
419 				*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
420 		}
421 		return 0;
422 	case COUNTER_FUNCTION_QUADRATURE_X2_A:
423 		if (synapse->signal->id == signal_a_id)
424 			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
425 		return 0;
426 	case COUNTER_FUNCTION_QUADRATURE_X4:
427 		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
428 		return 0;
429 	default:
430 		/* should never reach this path */
431 		return -EINVAL;
432 	}
433 }
434 
435 enum {
436 	QUAD8_EVENT_CARRY = 0,
437 	QUAD8_EVENT_COMPARE = 1,
438 	QUAD8_EVENT_CARRY_BORROW = 2,
439 	QUAD8_EVENT_INDEX = 3,
440 };
441 
442 static int quad8_events_configure(struct counter_device *counter)
443 {
444 	struct quad8 *const priv = counter_priv(counter);
445 	unsigned long irq_enabled = 0;
446 	unsigned long irqflags;
447 	struct counter_event_node *event_node;
448 	unsigned int next_irq_trigger;
449 	unsigned long ior_cfg;
450 
451 	spin_lock_irqsave(&priv->lock, irqflags);
452 
453 	list_for_each_entry(event_node, &counter->events_list, l) {
454 		switch (event_node->event) {
455 		case COUNTER_EVENT_OVERFLOW:
456 			next_irq_trigger = QUAD8_EVENT_CARRY;
457 			break;
458 		case COUNTER_EVENT_THRESHOLD:
459 			next_irq_trigger = QUAD8_EVENT_COMPARE;
460 			break;
461 		case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
462 			next_irq_trigger = QUAD8_EVENT_CARRY_BORROW;
463 			break;
464 		case COUNTER_EVENT_INDEX:
465 			next_irq_trigger = QUAD8_EVENT_INDEX;
466 			break;
467 		default:
468 			/* should never reach this path */
469 			spin_unlock_irqrestore(&priv->lock, irqflags);
470 			return -EINVAL;
471 		}
472 
473 		/* Enable IRQ line */
474 		irq_enabled |= BIT(event_node->channel);
475 
476 		/* Skip configuration if it is the same as previously set */
477 		if (priv->irq_trigger[event_node->channel] == next_irq_trigger)
478 			continue;
479 
480 		/* Save new IRQ function configuration */
481 		priv->irq_trigger[event_node->channel] = next_irq_trigger;
482 
483 		/* Load configuration to I/O Control Register */
484 		ior_cfg = priv->ab_enable[event_node->channel] |
485 			  priv->preset_enable[event_node->channel] << 1 |
486 			  priv->irq_trigger[event_node->channel] << 3;
487 		iowrite8(QUAD8_CTR_IOR | ior_cfg,
488 			 &priv->reg->channel[event_node->channel].control);
489 	}
490 
491 	iowrite8(irq_enabled, &priv->reg->index_interrupt);
492 
493 	spin_unlock_irqrestore(&priv->lock, irqflags);
494 
495 	return 0;
496 }
497 
498 static int quad8_watch_validate(struct counter_device *counter,
499 				const struct counter_watch *watch)
500 {
501 	struct counter_event_node *event_node;
502 
503 	if (watch->channel > QUAD8_NUM_COUNTERS - 1)
504 		return -EINVAL;
505 
506 	switch (watch->event) {
507 	case COUNTER_EVENT_OVERFLOW:
508 	case COUNTER_EVENT_THRESHOLD:
509 	case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
510 	case COUNTER_EVENT_INDEX:
511 		list_for_each_entry(event_node, &counter->next_events_list, l)
512 			if (watch->channel == event_node->channel &&
513 				watch->event != event_node->event)
514 				return -EINVAL;
515 		return 0;
516 	default:
517 		return -EINVAL;
518 	}
519 }
520 
521 static const struct counter_ops quad8_ops = {
522 	.signal_read = quad8_signal_read,
523 	.count_read = quad8_count_read,
524 	.count_write = quad8_count_write,
525 	.function_read = quad8_function_read,
526 	.function_write = quad8_function_write,
527 	.action_read = quad8_action_read,
528 	.events_configure = quad8_events_configure,
529 	.watch_validate = quad8_watch_validate,
530 };
531 
532 static const char *const quad8_index_polarity_modes[] = {
533 	"negative",
534 	"positive"
535 };
536 
537 static int quad8_index_polarity_get(struct counter_device *counter,
538 				    struct counter_signal *signal,
539 				    u32 *index_polarity)
540 {
541 	const struct quad8 *const priv = counter_priv(counter);
542 	const size_t channel_id = signal->id - 16;
543 
544 	*index_polarity = priv->index_polarity[channel_id];
545 
546 	return 0;
547 }
548 
549 static int quad8_index_polarity_set(struct counter_device *counter,
550 				    struct counter_signal *signal,
551 				    u32 index_polarity)
552 {
553 	struct quad8 *const priv = counter_priv(counter);
554 	const size_t channel_id = signal->id - 16;
555 	u8 __iomem *const control = &priv->reg->channel[channel_id].control;
556 	unsigned long irqflags;
557 	unsigned int idr_cfg = index_polarity << 1;
558 
559 	spin_lock_irqsave(&priv->lock, irqflags);
560 
561 	idr_cfg |= priv->synchronous_mode[channel_id];
562 
563 	priv->index_polarity[channel_id] = index_polarity;
564 
565 	/* Load Index Control configuration to Index Control Register */
566 	iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
567 
568 	spin_unlock_irqrestore(&priv->lock, irqflags);
569 
570 	return 0;
571 }
572 
573 static int quad8_polarity_read(struct counter_device *counter,
574 			       struct counter_signal *signal,
575 			       enum counter_signal_polarity *polarity)
576 {
577 	int err;
578 	u32 index_polarity;
579 
580 	err = quad8_index_polarity_get(counter, signal, &index_polarity);
581 	if (err)
582 		return err;
583 
584 	*polarity = (index_polarity) ? COUNTER_SIGNAL_POLARITY_POSITIVE :
585 		COUNTER_SIGNAL_POLARITY_NEGATIVE;
586 
587 	return 0;
588 }
589 
590 static int quad8_polarity_write(struct counter_device *counter,
591 				struct counter_signal *signal,
592 				enum counter_signal_polarity polarity)
593 {
594 	const u32 pol = (polarity == COUNTER_SIGNAL_POLARITY_POSITIVE) ? 1 : 0;
595 
596 	return quad8_index_polarity_set(counter, signal, pol);
597 }
598 
599 static const char *const quad8_synchronous_modes[] = {
600 	"non-synchronous",
601 	"synchronous"
602 };
603 
604 static int quad8_synchronous_mode_get(struct counter_device *counter,
605 				      struct counter_signal *signal,
606 				      u32 *synchronous_mode)
607 {
608 	const struct quad8 *const priv = counter_priv(counter);
609 	const size_t channel_id = signal->id - 16;
610 
611 	*synchronous_mode = priv->synchronous_mode[channel_id];
612 
613 	return 0;
614 }
615 
616 static int quad8_synchronous_mode_set(struct counter_device *counter,
617 				      struct counter_signal *signal,
618 				      u32 synchronous_mode)
619 {
620 	struct quad8 *const priv = counter_priv(counter);
621 	const size_t channel_id = signal->id - 16;
622 	u8 __iomem *const control = &priv->reg->channel[channel_id].control;
623 	unsigned long irqflags;
624 	unsigned int idr_cfg = synchronous_mode;
625 
626 	spin_lock_irqsave(&priv->lock, irqflags);
627 
628 	idr_cfg |= priv->index_polarity[channel_id] << 1;
629 
630 	/* Index function must be non-synchronous in non-quadrature mode */
631 	if (synchronous_mode && !priv->quadrature_mode[channel_id]) {
632 		spin_unlock_irqrestore(&priv->lock, irqflags);
633 		return -EINVAL;
634 	}
635 
636 	priv->synchronous_mode[channel_id] = synchronous_mode;
637 
638 	/* Load Index Control configuration to Index Control Register */
639 	iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
640 
641 	spin_unlock_irqrestore(&priv->lock, irqflags);
642 
643 	return 0;
644 }
645 
646 static int quad8_count_floor_read(struct counter_device *counter,
647 				  struct counter_count *count, u64 *floor)
648 {
649 	/* Only a floor of 0 is supported */
650 	*floor = 0;
651 
652 	return 0;
653 }
654 
655 static int quad8_count_mode_read(struct counter_device *counter,
656 				 struct counter_count *count,
657 				 enum counter_count_mode *cnt_mode)
658 {
659 	const struct quad8 *const priv = counter_priv(counter);
660 
661 	/* Map 104-QUAD-8 count mode to Generic Counter count mode */
662 	switch (priv->count_mode[count->id]) {
663 	case 0:
664 		*cnt_mode = COUNTER_COUNT_MODE_NORMAL;
665 		break;
666 	case 1:
667 		*cnt_mode = COUNTER_COUNT_MODE_RANGE_LIMIT;
668 		break;
669 	case 2:
670 		*cnt_mode = COUNTER_COUNT_MODE_NON_RECYCLE;
671 		break;
672 	case 3:
673 		*cnt_mode = COUNTER_COUNT_MODE_MODULO_N;
674 		break;
675 	}
676 
677 	return 0;
678 }
679 
680 static int quad8_count_mode_write(struct counter_device *counter,
681 				  struct counter_count *count,
682 				  enum counter_count_mode cnt_mode)
683 {
684 	struct quad8 *const priv = counter_priv(counter);
685 	unsigned int count_mode;
686 	unsigned int mode_cfg;
687 	u8 __iomem *const control = &priv->reg->channel[count->id].control;
688 	unsigned long irqflags;
689 
690 	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
691 	switch (cnt_mode) {
692 	case COUNTER_COUNT_MODE_NORMAL:
693 		count_mode = 0;
694 		break;
695 	case COUNTER_COUNT_MODE_RANGE_LIMIT:
696 		count_mode = 1;
697 		break;
698 	case COUNTER_COUNT_MODE_NON_RECYCLE:
699 		count_mode = 2;
700 		break;
701 	case COUNTER_COUNT_MODE_MODULO_N:
702 		count_mode = 3;
703 		break;
704 	default:
705 		/* should never reach this path */
706 		return -EINVAL;
707 	}
708 
709 	spin_lock_irqsave(&priv->lock, irqflags);
710 
711 	priv->count_mode[count->id] = count_mode;
712 
713 	/* Set count mode configuration value */
714 	mode_cfg = count_mode << 1;
715 
716 	/* Add quadrature mode configuration */
717 	if (priv->quadrature_mode[count->id])
718 		mode_cfg |= (priv->quadrature_scale[count->id] + 1) << 3;
719 
720 	/* Load mode configuration to Counter Mode Register */
721 	iowrite8(QUAD8_CTR_CMR | mode_cfg, control);
722 
723 	spin_unlock_irqrestore(&priv->lock, irqflags);
724 
725 	return 0;
726 }
727 
728 static int quad8_count_enable_read(struct counter_device *counter,
729 				   struct counter_count *count, u8 *enable)
730 {
731 	const struct quad8 *const priv = counter_priv(counter);
732 
733 	*enable = priv->ab_enable[count->id];
734 
735 	return 0;
736 }
737 
738 static int quad8_count_enable_write(struct counter_device *counter,
739 				    struct counter_count *count, u8 enable)
740 {
741 	struct quad8 *const priv = counter_priv(counter);
742 	u8 __iomem *const control = &priv->reg->channel[count->id].control;
743 	unsigned long irqflags;
744 	unsigned int ior_cfg;
745 
746 	spin_lock_irqsave(&priv->lock, irqflags);
747 
748 	priv->ab_enable[count->id] = enable;
749 
750 	ior_cfg = enable | priv->preset_enable[count->id] << 1 |
751 		  priv->irq_trigger[count->id] << 3;
752 
753 	/* Load I/O control configuration */
754 	iowrite8(QUAD8_CTR_IOR | ior_cfg, control);
755 
756 	spin_unlock_irqrestore(&priv->lock, irqflags);
757 
758 	return 0;
759 }
760 
761 static const char *const quad8_noise_error_states[] = {
762 	"No excessive noise is present at the count inputs",
763 	"Excessive noise is present at the count inputs"
764 };
765 
766 static int quad8_error_noise_get(struct counter_device *counter,
767 				 struct counter_count *count, u32 *noise_error)
768 {
769 	const struct quad8 *const priv = counter_priv(counter);
770 	u8 __iomem *const flag_addr = &priv->reg->channel[count->id].control;
771 
772 	*noise_error = !!(ioread8(flag_addr) & QUAD8_FLAG_E);
773 
774 	return 0;
775 }
776 
777 static int quad8_count_preset_read(struct counter_device *counter,
778 				   struct counter_count *count, u64 *preset)
779 {
780 	const struct quad8 *const priv = counter_priv(counter);
781 
782 	*preset = priv->preset[count->id];
783 
784 	return 0;
785 }
786 
787 static void quad8_preset_register_set(struct quad8 *const priv, const int id,
788 				      const unsigned int preset)
789 {
790 	struct channel_reg __iomem *const chan = priv->reg->channel + id;
791 	int i;
792 
793 	priv->preset[id] = preset;
794 
795 	/* Reset Byte Pointer */
796 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
797 
798 	/* Set Preset Register */
799 	for (i = 0; i < 3; i++)
800 		iowrite8(preset >> (8 * i), &chan->data);
801 }
802 
803 static int quad8_count_preset_write(struct counter_device *counter,
804 				    struct counter_count *count, u64 preset)
805 {
806 	struct quad8 *const priv = counter_priv(counter);
807 	unsigned long irqflags;
808 
809 	/* Only 24-bit values are supported */
810 	if (preset > 0xFFFFFF)
811 		return -ERANGE;
812 
813 	spin_lock_irqsave(&priv->lock, irqflags);
814 
815 	quad8_preset_register_set(priv, count->id, preset);
816 
817 	spin_unlock_irqrestore(&priv->lock, irqflags);
818 
819 	return 0;
820 }
821 
822 static int quad8_count_ceiling_read(struct counter_device *counter,
823 				    struct counter_count *count, u64 *ceiling)
824 {
825 	struct quad8 *const priv = counter_priv(counter);
826 	unsigned long irqflags;
827 
828 	spin_lock_irqsave(&priv->lock, irqflags);
829 
830 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
831 	switch (priv->count_mode[count->id]) {
832 	case 1:
833 	case 3:
834 		*ceiling = priv->preset[count->id];
835 		break;
836 	default:
837 		/* By default 0x1FFFFFF (25 bits unsigned) is maximum count */
838 		*ceiling = 0x1FFFFFF;
839 		break;
840 	}
841 
842 	spin_unlock_irqrestore(&priv->lock, irqflags);
843 
844 	return 0;
845 }
846 
847 static int quad8_count_ceiling_write(struct counter_device *counter,
848 				     struct counter_count *count, u64 ceiling)
849 {
850 	struct quad8 *const priv = counter_priv(counter);
851 	unsigned long irqflags;
852 
853 	/* Only 24-bit values are supported */
854 	if (ceiling > 0xFFFFFF)
855 		return -ERANGE;
856 
857 	spin_lock_irqsave(&priv->lock, irqflags);
858 
859 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
860 	switch (priv->count_mode[count->id]) {
861 	case 1:
862 	case 3:
863 		quad8_preset_register_set(priv, count->id, ceiling);
864 		spin_unlock_irqrestore(&priv->lock, irqflags);
865 		return 0;
866 	}
867 
868 	spin_unlock_irqrestore(&priv->lock, irqflags);
869 
870 	return -EINVAL;
871 }
872 
873 static int quad8_count_preset_enable_read(struct counter_device *counter,
874 					  struct counter_count *count,
875 					  u8 *preset_enable)
876 {
877 	const struct quad8 *const priv = counter_priv(counter);
878 
879 	*preset_enable = !priv->preset_enable[count->id];
880 
881 	return 0;
882 }
883 
884 static int quad8_count_preset_enable_write(struct counter_device *counter,
885 					   struct counter_count *count,
886 					   u8 preset_enable)
887 {
888 	struct quad8 *const priv = counter_priv(counter);
889 	u8 __iomem *const control = &priv->reg->channel[count->id].control;
890 	unsigned long irqflags;
891 	unsigned int ior_cfg;
892 
893 	/* Preset enable is active low in Input/Output Control register */
894 	preset_enable = !preset_enable;
895 
896 	spin_lock_irqsave(&priv->lock, irqflags);
897 
898 	priv->preset_enable[count->id] = preset_enable;
899 
900 	ior_cfg = priv->ab_enable[count->id] | preset_enable << 1 |
901 		  priv->irq_trigger[count->id] << 3;
902 
903 	/* Load I/O control configuration to Input / Output Control Register */
904 	iowrite8(QUAD8_CTR_IOR | ior_cfg, control);
905 
906 	spin_unlock_irqrestore(&priv->lock, irqflags);
907 
908 	return 0;
909 }
910 
911 static int quad8_signal_cable_fault_read(struct counter_device *counter,
912 					 struct counter_signal *signal,
913 					 u8 *cable_fault)
914 {
915 	struct quad8 *const priv = counter_priv(counter);
916 	const size_t channel_id = signal->id / 2;
917 	unsigned long irqflags;
918 	bool disabled;
919 	unsigned int status;
920 
921 	spin_lock_irqsave(&priv->lock, irqflags);
922 
923 	disabled = !(priv->cable_fault_enable & BIT(channel_id));
924 
925 	if (disabled) {
926 		spin_unlock_irqrestore(&priv->lock, irqflags);
927 		return -EINVAL;
928 	}
929 
930 	/* Logic 0 = cable fault */
931 	status = ioread8(&priv->reg->cable_status);
932 
933 	spin_unlock_irqrestore(&priv->lock, irqflags);
934 
935 	/* Mask respective channel and invert logic */
936 	*cable_fault = !(status & BIT(channel_id));
937 
938 	return 0;
939 }
940 
941 static int quad8_signal_cable_fault_enable_read(struct counter_device *counter,
942 						struct counter_signal *signal,
943 						u8 *enable)
944 {
945 	const struct quad8 *const priv = counter_priv(counter);
946 	const size_t channel_id = signal->id / 2;
947 
948 	*enable = !!(priv->cable_fault_enable & BIT(channel_id));
949 
950 	return 0;
951 }
952 
953 static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
954 						 struct counter_signal *signal,
955 						 u8 enable)
956 {
957 	struct quad8 *const priv = counter_priv(counter);
958 	const size_t channel_id = signal->id / 2;
959 	unsigned long irqflags;
960 	unsigned int cable_fault_enable;
961 
962 	spin_lock_irqsave(&priv->lock, irqflags);
963 
964 	if (enable)
965 		priv->cable_fault_enable |= BIT(channel_id);
966 	else
967 		priv->cable_fault_enable &= ~BIT(channel_id);
968 
969 	/* Enable is active low in Differential Encoder Cable Status register */
970 	cable_fault_enable = ~priv->cable_fault_enable;
971 
972 	iowrite8(cable_fault_enable, &priv->reg->cable_status);
973 
974 	spin_unlock_irqrestore(&priv->lock, irqflags);
975 
976 	return 0;
977 }
978 
979 static int quad8_signal_fck_prescaler_read(struct counter_device *counter,
980 					   struct counter_signal *signal,
981 					   u8 *prescaler)
982 {
983 	const struct quad8 *const priv = counter_priv(counter);
984 
985 	*prescaler = priv->fck_prescaler[signal->id / 2];
986 
987 	return 0;
988 }
989 
990 static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
991 					    struct counter_signal *signal,
992 					    u8 prescaler)
993 {
994 	struct quad8 *const priv = counter_priv(counter);
995 	const size_t channel_id = signal->id / 2;
996 	struct channel_reg __iomem *const chan = priv->reg->channel + channel_id;
997 	unsigned long irqflags;
998 
999 	spin_lock_irqsave(&priv->lock, irqflags);
1000 
1001 	priv->fck_prescaler[channel_id] = prescaler;
1002 
1003 	/* Reset Byte Pointer */
1004 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
1005 
1006 	/* Set filter clock factor */
1007 	iowrite8(prescaler, &chan->data);
1008 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
1009 		 &chan->control);
1010 
1011 	spin_unlock_irqrestore(&priv->lock, irqflags);
1012 
1013 	return 0;
1014 }
1015 
1016 static struct counter_comp quad8_signal_ext[] = {
1017 	COUNTER_COMP_SIGNAL_BOOL("cable_fault", quad8_signal_cable_fault_read,
1018 				 NULL),
1019 	COUNTER_COMP_SIGNAL_BOOL("cable_fault_enable",
1020 				 quad8_signal_cable_fault_enable_read,
1021 				 quad8_signal_cable_fault_enable_write),
1022 	COUNTER_COMP_SIGNAL_U8("filter_clock_prescaler",
1023 			       quad8_signal_fck_prescaler_read,
1024 			       quad8_signal_fck_prescaler_write)
1025 };
1026 
1027 static const enum counter_signal_polarity quad8_polarities[] = {
1028 	COUNTER_SIGNAL_POLARITY_POSITIVE,
1029 	COUNTER_SIGNAL_POLARITY_NEGATIVE,
1030 };
1031 
1032 static DEFINE_COUNTER_AVAILABLE(quad8_polarity_available, quad8_polarities);
1033 
1034 static DEFINE_COUNTER_ENUM(quad8_index_pol_enum, quad8_index_polarity_modes);
1035 static DEFINE_COUNTER_ENUM(quad8_synch_mode_enum, quad8_synchronous_modes);
1036 
1037 static struct counter_comp quad8_index_ext[] = {
1038 	COUNTER_COMP_SIGNAL_ENUM("index_polarity", quad8_index_polarity_get,
1039 				 quad8_index_polarity_set,
1040 				 quad8_index_pol_enum),
1041 	COUNTER_COMP_POLARITY(quad8_polarity_read, quad8_polarity_write,
1042 			      quad8_polarity_available),
1043 	COUNTER_COMP_SIGNAL_ENUM("synchronous_mode", quad8_synchronous_mode_get,
1044 				 quad8_synchronous_mode_set,
1045 				 quad8_synch_mode_enum),
1046 };
1047 
1048 #define QUAD8_QUAD_SIGNAL(_id, _name) {		\
1049 	.id = (_id),				\
1050 	.name = (_name),			\
1051 	.ext = quad8_signal_ext,		\
1052 	.num_ext = ARRAY_SIZE(quad8_signal_ext)	\
1053 }
1054 
1055 #define	QUAD8_INDEX_SIGNAL(_id, _name) {	\
1056 	.id = (_id),				\
1057 	.name = (_name),			\
1058 	.ext = quad8_index_ext,			\
1059 	.num_ext = ARRAY_SIZE(quad8_index_ext)	\
1060 }
1061 
1062 static struct counter_signal quad8_signals[] = {
1063 	QUAD8_QUAD_SIGNAL(0, "Channel 1 Quadrature A"),
1064 	QUAD8_QUAD_SIGNAL(1, "Channel 1 Quadrature B"),
1065 	QUAD8_QUAD_SIGNAL(2, "Channel 2 Quadrature A"),
1066 	QUAD8_QUAD_SIGNAL(3, "Channel 2 Quadrature B"),
1067 	QUAD8_QUAD_SIGNAL(4, "Channel 3 Quadrature A"),
1068 	QUAD8_QUAD_SIGNAL(5, "Channel 3 Quadrature B"),
1069 	QUAD8_QUAD_SIGNAL(6, "Channel 4 Quadrature A"),
1070 	QUAD8_QUAD_SIGNAL(7, "Channel 4 Quadrature B"),
1071 	QUAD8_QUAD_SIGNAL(8, "Channel 5 Quadrature A"),
1072 	QUAD8_QUAD_SIGNAL(9, "Channel 5 Quadrature B"),
1073 	QUAD8_QUAD_SIGNAL(10, "Channel 6 Quadrature A"),
1074 	QUAD8_QUAD_SIGNAL(11, "Channel 6 Quadrature B"),
1075 	QUAD8_QUAD_SIGNAL(12, "Channel 7 Quadrature A"),
1076 	QUAD8_QUAD_SIGNAL(13, "Channel 7 Quadrature B"),
1077 	QUAD8_QUAD_SIGNAL(14, "Channel 8 Quadrature A"),
1078 	QUAD8_QUAD_SIGNAL(15, "Channel 8 Quadrature B"),
1079 	QUAD8_INDEX_SIGNAL(16, "Channel 1 Index"),
1080 	QUAD8_INDEX_SIGNAL(17, "Channel 2 Index"),
1081 	QUAD8_INDEX_SIGNAL(18, "Channel 3 Index"),
1082 	QUAD8_INDEX_SIGNAL(19, "Channel 4 Index"),
1083 	QUAD8_INDEX_SIGNAL(20, "Channel 5 Index"),
1084 	QUAD8_INDEX_SIGNAL(21, "Channel 6 Index"),
1085 	QUAD8_INDEX_SIGNAL(22, "Channel 7 Index"),
1086 	QUAD8_INDEX_SIGNAL(23, "Channel 8 Index")
1087 };
1088 
1089 #define QUAD8_COUNT_SYNAPSES(_id) {					\
1090 	{								\
1091 		.actions_list = quad8_synapse_actions_list,		\
1092 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1093 		.signal = quad8_signals + 2 * (_id)			\
1094 	},								\
1095 	{								\
1096 		.actions_list = quad8_synapse_actions_list,		\
1097 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1098 		.signal = quad8_signals + 2 * (_id) + 1			\
1099 	},								\
1100 	{								\
1101 		.actions_list = quad8_index_actions_list,		\
1102 		.num_actions = ARRAY_SIZE(quad8_index_actions_list),	\
1103 		.signal = quad8_signals + 2 * (_id) + 16		\
1104 	}								\
1105 }
1106 
1107 static struct counter_synapse quad8_count_synapses[][3] = {
1108 	QUAD8_COUNT_SYNAPSES(0), QUAD8_COUNT_SYNAPSES(1),
1109 	QUAD8_COUNT_SYNAPSES(2), QUAD8_COUNT_SYNAPSES(3),
1110 	QUAD8_COUNT_SYNAPSES(4), QUAD8_COUNT_SYNAPSES(5),
1111 	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
1112 };
1113 
1114 static const enum counter_count_mode quad8_cnt_modes[] = {
1115 	COUNTER_COUNT_MODE_NORMAL,
1116 	COUNTER_COUNT_MODE_RANGE_LIMIT,
1117 	COUNTER_COUNT_MODE_NON_RECYCLE,
1118 	COUNTER_COUNT_MODE_MODULO_N,
1119 };
1120 
1121 static DEFINE_COUNTER_AVAILABLE(quad8_count_mode_available, quad8_cnt_modes);
1122 
1123 static DEFINE_COUNTER_ENUM(quad8_error_noise_enum, quad8_noise_error_states);
1124 
1125 static struct counter_comp quad8_count_ext[] = {
1126 	COUNTER_COMP_CEILING(quad8_count_ceiling_read,
1127 			     quad8_count_ceiling_write),
1128 	COUNTER_COMP_FLOOR(quad8_count_floor_read, NULL),
1129 	COUNTER_COMP_COUNT_MODE(quad8_count_mode_read, quad8_count_mode_write,
1130 				quad8_count_mode_available),
1131 	COUNTER_COMP_DIRECTION(quad8_direction_read),
1132 	COUNTER_COMP_ENABLE(quad8_count_enable_read, quad8_count_enable_write),
1133 	COUNTER_COMP_COUNT_ENUM("error_noise", quad8_error_noise_get, NULL,
1134 				quad8_error_noise_enum),
1135 	COUNTER_COMP_PRESET(quad8_count_preset_read, quad8_count_preset_write),
1136 	COUNTER_COMP_PRESET_ENABLE(quad8_count_preset_enable_read,
1137 				   quad8_count_preset_enable_write),
1138 };
1139 
1140 #define QUAD8_COUNT(_id, _cntname) {					\
1141 	.id = (_id),							\
1142 	.name = (_cntname),						\
1143 	.functions_list = quad8_count_functions_list,			\
1144 	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
1145 	.synapses = quad8_count_synapses[(_id)],			\
1146 	.num_synapses =	2,						\
1147 	.ext = quad8_count_ext,						\
1148 	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
1149 }
1150 
1151 static struct counter_count quad8_counts[] = {
1152 	QUAD8_COUNT(0, "Channel 1 Count"),
1153 	QUAD8_COUNT(1, "Channel 2 Count"),
1154 	QUAD8_COUNT(2, "Channel 3 Count"),
1155 	QUAD8_COUNT(3, "Channel 4 Count"),
1156 	QUAD8_COUNT(4, "Channel 5 Count"),
1157 	QUAD8_COUNT(5, "Channel 6 Count"),
1158 	QUAD8_COUNT(6, "Channel 7 Count"),
1159 	QUAD8_COUNT(7, "Channel 8 Count")
1160 };
1161 
1162 static irqreturn_t quad8_irq_handler(int irq, void *private)
1163 {
1164 	struct counter_device *counter = private;
1165 	struct quad8 *const priv = counter_priv(counter);
1166 	unsigned long irq_status;
1167 	unsigned long channel;
1168 	u8 event;
1169 
1170 	irq_status = ioread8(&priv->reg->interrupt_status);
1171 	if (!irq_status)
1172 		return IRQ_NONE;
1173 
1174 	for_each_set_bit(channel, &irq_status, QUAD8_NUM_COUNTERS) {
1175 		switch (priv->irq_trigger[channel]) {
1176 		case QUAD8_EVENT_CARRY:
1177 			event = COUNTER_EVENT_OVERFLOW;
1178 				break;
1179 		case QUAD8_EVENT_COMPARE:
1180 			event = COUNTER_EVENT_THRESHOLD;
1181 				break;
1182 		case QUAD8_EVENT_CARRY_BORROW:
1183 			event = COUNTER_EVENT_OVERFLOW_UNDERFLOW;
1184 				break;
1185 		case QUAD8_EVENT_INDEX:
1186 			event = COUNTER_EVENT_INDEX;
1187 				break;
1188 		default:
1189 			/* should never reach this path */
1190 			WARN_ONCE(true, "invalid interrupt trigger function %u configured for channel %lu\n",
1191 				  priv->irq_trigger[channel], channel);
1192 			continue;
1193 		}
1194 
1195 		counter_push_event(counter, event, channel);
1196 	}
1197 
1198 	/* Clear pending interrupts on device */
1199 	iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, &priv->reg->channel_oper);
1200 
1201 	return IRQ_HANDLED;
1202 }
1203 
1204 static void quad8_init_counter(struct channel_reg __iomem *const chan)
1205 {
1206 	unsigned long i;
1207 
1208 	/* Reset Byte Pointer */
1209 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
1210 	/* Reset filter clock factor */
1211 	iowrite8(0, &chan->data);
1212 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
1213 		 &chan->control);
1214 	/* Reset Byte Pointer */
1215 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
1216 	/* Reset Preset Register */
1217 	for (i = 0; i < 3; i++)
1218 		iowrite8(0x00, &chan->data);
1219 	/* Reset Borrow, Carry, Compare, and Sign flags */
1220 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, &chan->control);
1221 	/* Reset Error flag */
1222 	iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, &chan->control);
1223 	/* Binary encoding; Normal count; non-quadrature mode */
1224 	iowrite8(QUAD8_CTR_CMR, &chan->control);
1225 	/* Disable A and B inputs; preset on index; FLG1 as Carry */
1226 	iowrite8(QUAD8_CTR_IOR, &chan->control);
1227 	/* Disable index function; negative index polarity */
1228 	iowrite8(QUAD8_CTR_IDR, &chan->control);
1229 }
1230 
1231 static int quad8_probe(struct device *dev, unsigned int id)
1232 {
1233 	struct counter_device *counter;
1234 	struct quad8 *priv;
1235 	unsigned long i;
1236 	int err;
1237 
1238 	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
1239 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
1240 			base[id], base[id] + QUAD8_EXTENT);
1241 		return -EBUSY;
1242 	}
1243 
1244 	counter = devm_counter_alloc(dev, sizeof(*priv));
1245 	if (!counter)
1246 		return -ENOMEM;
1247 	priv = counter_priv(counter);
1248 
1249 	priv->reg = devm_ioport_map(dev, base[id], QUAD8_EXTENT);
1250 	if (!priv->reg)
1251 		return -ENOMEM;
1252 
1253 	/* Initialize Counter device and driver data */
1254 	counter->name = dev_name(dev);
1255 	counter->parent = dev;
1256 	counter->ops = &quad8_ops;
1257 	counter->counts = quad8_counts;
1258 	counter->num_counts = ARRAY_SIZE(quad8_counts);
1259 	counter->signals = quad8_signals;
1260 	counter->num_signals = ARRAY_SIZE(quad8_signals);
1261 
1262 	spin_lock_init(&priv->lock);
1263 
1264 	/* Reset Index/Interrupt Register */
1265 	iowrite8(0x00, &priv->reg->index_interrupt);
1266 	/* Reset all counters and disable interrupt function */
1267 	iowrite8(QUAD8_CHAN_OP_RESET_COUNTERS, &priv->reg->channel_oper);
1268 	/* Set initial configuration for all counters */
1269 	for (i = 0; i < QUAD8_NUM_COUNTERS; i++)
1270 		quad8_init_counter(priv->reg->channel + i);
1271 	/* Disable Differential Encoder Cable Status for all channels */
1272 	iowrite8(0xFF, &priv->reg->cable_status);
1273 	/* Enable all counters and enable interrupt function */
1274 	iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, &priv->reg->channel_oper);
1275 
1276 	err = devm_request_irq(&counter->dev, irq[id], quad8_irq_handler,
1277 			       IRQF_SHARED, counter->name, counter);
1278 	if (err)
1279 		return err;
1280 
1281 	err = devm_counter_add(dev, counter);
1282 	if (err < 0)
1283 		return dev_err_probe(dev, err, "Failed to add counter\n");
1284 
1285 	return 0;
1286 }
1287 
1288 static struct isa_driver quad8_driver = {
1289 	.probe = quad8_probe,
1290 	.driver = {
1291 		.name = "104-quad-8"
1292 	}
1293 };
1294 
1295 module_isa_driver_with_irq(quad8_driver, num_quad8, num_irq);
1296 
1297 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
1298 MODULE_DESCRIPTION("ACCES 104-QUAD-8 driver");
1299 MODULE_LICENSE("GPL v2");
1300 MODULE_IMPORT_NS(COUNTER);
1301