xref: /openbmc/linux/drivers/counter/104-quad-8.c (revision be58f710)
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/isa.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/types.h>
19 
20 #define QUAD8_EXTENT 32
21 
22 static unsigned int base[max_num_isa_dev(QUAD8_EXTENT)];
23 static unsigned int num_quad8;
24 module_param_hw_array(base, uint, ioport, &num_quad8, 0);
25 MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
26 
27 #define QUAD8_NUM_COUNTERS 8
28 
29 /**
30  * struct quad8 - device private data structure
31  * @lock:		lock to prevent clobbering device states during R/W ops
32  * @counter:		instance of the counter_device
33  * @fck_prescaler:	array of filter clock prescaler configurations
34  * @preset:		array of preset values
35  * @count_mode:		array of count mode configurations
36  * @quadrature_mode:	array of quadrature mode configurations
37  * @quadrature_scale:	array of quadrature mode scale configurations
38  * @ab_enable:		array of A and B inputs enable configurations
39  * @preset_enable:	array of set_to_preset_on_index attribute configurations
40  * @synchronous_mode:	array of index function synchronous mode configurations
41  * @index_polarity:	array of index function polarity configurations
42  * @cable_fault_enable:	differential encoder cable status enable configurations
43  * @base:		base port address of the device
44  */
45 struct quad8 {
46 	struct mutex lock;
47 	struct counter_device counter;
48 	unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
49 	unsigned int preset[QUAD8_NUM_COUNTERS];
50 	unsigned int count_mode[QUAD8_NUM_COUNTERS];
51 	unsigned int quadrature_mode[QUAD8_NUM_COUNTERS];
52 	unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
53 	unsigned int ab_enable[QUAD8_NUM_COUNTERS];
54 	unsigned int preset_enable[QUAD8_NUM_COUNTERS];
55 	unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
56 	unsigned int index_polarity[QUAD8_NUM_COUNTERS];
57 	unsigned int cable_fault_enable;
58 	unsigned int base;
59 };
60 
61 #define QUAD8_REG_CHAN_OP 0x11
62 #define QUAD8_REG_INDEX_INPUT_LEVELS 0x16
63 #define QUAD8_DIFF_ENCODER_CABLE_STATUS 0x17
64 /* Borrow Toggle flip-flop */
65 #define QUAD8_FLAG_BT BIT(0)
66 /* Carry Toggle flip-flop */
67 #define QUAD8_FLAG_CT BIT(1)
68 /* Error flag */
69 #define QUAD8_FLAG_E BIT(4)
70 /* Up/Down flag */
71 #define QUAD8_FLAG_UD BIT(5)
72 /* Reset and Load Signal Decoders */
73 #define QUAD8_CTR_RLD 0x00
74 /* Counter Mode Register */
75 #define QUAD8_CTR_CMR 0x20
76 /* Input / Output Control Register */
77 #define QUAD8_CTR_IOR 0x40
78 /* Index Control Register */
79 #define QUAD8_CTR_IDR 0x60
80 /* Reset Byte Pointer (three byte data pointer) */
81 #define QUAD8_RLD_RESET_BP 0x01
82 /* Reset Counter */
83 #define QUAD8_RLD_RESET_CNTR 0x02
84 /* Reset Borrow Toggle, Carry Toggle, Compare Toggle, and Sign flags */
85 #define QUAD8_RLD_RESET_FLAGS 0x04
86 /* Reset Error flag */
87 #define QUAD8_RLD_RESET_E 0x06
88 /* Preset Register to Counter */
89 #define QUAD8_RLD_PRESET_CNTR 0x08
90 /* Transfer Counter to Output Latch */
91 #define QUAD8_RLD_CNTR_OUT 0x10
92 /* Transfer Preset Register LSB to FCK Prescaler */
93 #define QUAD8_RLD_PRESET_PSC 0x18
94 #define QUAD8_CHAN_OP_ENABLE_COUNTERS 0x00
95 #define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
96 #define QUAD8_CMR_QUADRATURE_X1 0x08
97 #define QUAD8_CMR_QUADRATURE_X2 0x10
98 #define QUAD8_CMR_QUADRATURE_X4 0x18
99 
100 static int quad8_signal_read(struct counter_device *counter,
101 			     struct counter_signal *signal,
102 			     enum counter_signal_level *level)
103 {
104 	const struct quad8 *const priv = counter->priv;
105 	unsigned int state;
106 
107 	/* Only Index signal levels can be read */
108 	if (signal->id < 16)
109 		return -EINVAL;
110 
111 	state = inb(priv->base + QUAD8_REG_INDEX_INPUT_LEVELS)
112 		& BIT(signal->id - 16);
113 
114 	*level = (state) ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
115 
116 	return 0;
117 }
118 
119 static int quad8_count_read(struct counter_device *counter,
120 	struct counter_count *count, unsigned long *val)
121 {
122 	struct quad8 *const priv = counter->priv;
123 	const int base_offset = priv->base + 2 * count->id;
124 	unsigned int flags;
125 	unsigned int borrow;
126 	unsigned int carry;
127 	int i;
128 
129 	flags = inb(base_offset + 1);
130 	borrow = flags & QUAD8_FLAG_BT;
131 	carry = !!(flags & QUAD8_FLAG_CT);
132 
133 	/* Borrow XOR Carry effectively doubles count range */
134 	*val = (unsigned long)(borrow ^ carry) << 24;
135 
136 	mutex_lock(&priv->lock);
137 
138 	/* Reset Byte Pointer; transfer Counter to Output Latch */
139 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
140 	     base_offset + 1);
141 
142 	for (i = 0; i < 3; i++)
143 		*val |= (unsigned long)inb(base_offset) << (8 * i);
144 
145 	mutex_unlock(&priv->lock);
146 
147 	return 0;
148 }
149 
150 static int quad8_count_write(struct counter_device *counter,
151 	struct counter_count *count, unsigned long val)
152 {
153 	struct quad8 *const priv = counter->priv;
154 	const int base_offset = priv->base + 2 * count->id;
155 	int i;
156 
157 	/* Only 24-bit values are supported */
158 	if (val > 0xFFFFFF)
159 		return -ERANGE;
160 
161 	mutex_lock(&priv->lock);
162 
163 	/* Reset Byte Pointer */
164 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
165 
166 	/* Counter can only be set via Preset Register */
167 	for (i = 0; i < 3; i++)
168 		outb(val >> (8 * i), base_offset);
169 
170 	/* Transfer Preset Register to Counter */
171 	outb(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, base_offset + 1);
172 
173 	/* Reset Byte Pointer */
174 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
175 
176 	/* Set Preset Register back to original value */
177 	val = priv->preset[count->id];
178 	for (i = 0; i < 3; i++)
179 		outb(val >> (8 * i), base_offset);
180 
181 	/* Reset Borrow, Carry, Compare, and Sign flags */
182 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
183 	/* Reset Error flag */
184 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
185 
186 	mutex_unlock(&priv->lock);
187 
188 	return 0;
189 }
190 
191 enum quad8_count_function {
192 	QUAD8_COUNT_FUNCTION_PULSE_DIRECTION = 0,
193 	QUAD8_COUNT_FUNCTION_QUADRATURE_X1,
194 	QUAD8_COUNT_FUNCTION_QUADRATURE_X2,
195 	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
196 };
197 
198 static const enum counter_function quad8_count_functions_list[] = {
199 	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_FUNCTION_PULSE_DIRECTION,
200 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_FUNCTION_QUADRATURE_X1_A,
201 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_FUNCTION_QUADRATURE_X2_A,
202 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X4] = COUNTER_FUNCTION_QUADRATURE_X4
203 };
204 
205 static int quad8_function_get(struct counter_device *counter,
206 	struct counter_count *count, size_t *function)
207 {
208 	struct quad8 *const priv = counter->priv;
209 	const int id = count->id;
210 
211 	mutex_lock(&priv->lock);
212 
213 	if (priv->quadrature_mode[id])
214 		switch (priv->quadrature_scale[id]) {
215 		case 0:
216 			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X1;
217 			break;
218 		case 1:
219 			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X2;
220 			break;
221 		case 2:
222 			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X4;
223 			break;
224 		}
225 	else
226 		*function = QUAD8_COUNT_FUNCTION_PULSE_DIRECTION;
227 
228 	mutex_unlock(&priv->lock);
229 
230 	return 0;
231 }
232 
233 static int quad8_function_set(struct counter_device *counter,
234 	struct counter_count *count, size_t function)
235 {
236 	struct quad8 *const priv = counter->priv;
237 	const int id = count->id;
238 	unsigned int *const quadrature_mode = priv->quadrature_mode + id;
239 	unsigned int *const scale = priv->quadrature_scale + id;
240 	unsigned int *const synchronous_mode = priv->synchronous_mode + id;
241 	const int base_offset = priv->base + 2 * id + 1;
242 	unsigned int mode_cfg;
243 	unsigned int idr_cfg;
244 
245 	mutex_lock(&priv->lock);
246 
247 	mode_cfg = priv->count_mode[id] << 1;
248 	idr_cfg = priv->index_polarity[id] << 1;
249 
250 	if (function == QUAD8_COUNT_FUNCTION_PULSE_DIRECTION) {
251 		*quadrature_mode = 0;
252 
253 		/* Quadrature scaling only available in quadrature mode */
254 		*scale = 0;
255 
256 		/* Synchronous function not supported in non-quadrature mode */
257 		if (*synchronous_mode) {
258 			*synchronous_mode = 0;
259 			/* Disable synchronous function mode */
260 			outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
261 		}
262 	} else {
263 		*quadrature_mode = 1;
264 
265 		switch (function) {
266 		case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
267 			*scale = 0;
268 			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
269 			break;
270 		case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
271 			*scale = 1;
272 			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
273 			break;
274 		case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
275 			*scale = 2;
276 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
277 			break;
278 		default:
279 			/* should never reach this path */
280 			mutex_unlock(&priv->lock);
281 			return -EINVAL;
282 		}
283 	}
284 
285 	/* Load mode configuration to Counter Mode Register */
286 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
287 
288 	mutex_unlock(&priv->lock);
289 
290 	return 0;
291 }
292 
293 static void quad8_direction_get(struct counter_device *counter,
294 	struct counter_count *count, enum counter_count_direction *direction)
295 {
296 	const struct quad8 *const priv = counter->priv;
297 	unsigned int ud_flag;
298 	const unsigned int flag_addr = priv->base + 2 * count->id + 1;
299 
300 	/* U/D flag: nonzero = up, zero = down */
301 	ud_flag = inb(flag_addr) & QUAD8_FLAG_UD;
302 
303 	*direction = (ud_flag) ? COUNTER_COUNT_DIRECTION_FORWARD :
304 		COUNTER_COUNT_DIRECTION_BACKWARD;
305 }
306 
307 enum quad8_synapse_action {
308 	QUAD8_SYNAPSE_ACTION_NONE = 0,
309 	QUAD8_SYNAPSE_ACTION_RISING_EDGE,
310 	QUAD8_SYNAPSE_ACTION_FALLING_EDGE,
311 	QUAD8_SYNAPSE_ACTION_BOTH_EDGES
312 };
313 
314 static const enum counter_synapse_action quad8_index_actions_list[] = {
315 	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
316 	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE
317 };
318 
319 static const enum counter_synapse_action quad8_synapse_actions_list[] = {
320 	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
321 	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
322 	[QUAD8_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
323 	[QUAD8_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
324 };
325 
326 static int quad8_action_get(struct counter_device *counter,
327 	struct counter_count *count, struct counter_synapse *synapse,
328 	size_t *action)
329 {
330 	struct quad8 *const priv = counter->priv;
331 	int err;
332 	size_t function = 0;
333 	const size_t signal_a_id = count->synapses[0].signal->id;
334 	enum counter_count_direction direction;
335 
336 	/* Handle Index signals */
337 	if (synapse->signal->id >= 16) {
338 		if (priv->preset_enable[count->id])
339 			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
340 		else
341 			*action = QUAD8_SYNAPSE_ACTION_NONE;
342 
343 		return 0;
344 	}
345 
346 	err = quad8_function_get(counter, count, &function);
347 	if (err)
348 		return err;
349 
350 	/* Default action mode */
351 	*action = QUAD8_SYNAPSE_ACTION_NONE;
352 
353 	/* Determine action mode based on current count function mode */
354 	switch (function) {
355 	case QUAD8_COUNT_FUNCTION_PULSE_DIRECTION:
356 		if (synapse->signal->id == signal_a_id)
357 			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
358 		return 0;
359 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
360 		if (synapse->signal->id == signal_a_id) {
361 			quad8_direction_get(counter, count, &direction);
362 
363 			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
364 				*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
365 			else
366 				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
367 		}
368 		return 0;
369 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
370 		if (synapse->signal->id == signal_a_id)
371 			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
372 		return 0;
373 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
374 		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
375 		return 0;
376 	default:
377 		/* should never reach this path */
378 		return -EINVAL;
379 	}
380 }
381 
382 static const struct counter_ops quad8_ops = {
383 	.signal_read = quad8_signal_read,
384 	.count_read = quad8_count_read,
385 	.count_write = quad8_count_write,
386 	.function_get = quad8_function_get,
387 	.function_set = quad8_function_set,
388 	.action_get = quad8_action_get
389 };
390 
391 static const char *const quad8_index_polarity_modes[] = {
392 	"negative",
393 	"positive"
394 };
395 
396 static int quad8_index_polarity_get(struct counter_device *counter,
397 	struct counter_signal *signal, size_t *index_polarity)
398 {
399 	const struct quad8 *const priv = counter->priv;
400 	const size_t channel_id = signal->id - 16;
401 
402 	*index_polarity = priv->index_polarity[channel_id];
403 
404 	return 0;
405 }
406 
407 static int quad8_index_polarity_set(struct counter_device *counter,
408 	struct counter_signal *signal, size_t index_polarity)
409 {
410 	struct quad8 *const priv = counter->priv;
411 	const size_t channel_id = signal->id - 16;
412 	const int base_offset = priv->base + 2 * channel_id + 1;
413 	unsigned int idr_cfg = index_polarity << 1;
414 
415 	mutex_lock(&priv->lock);
416 
417 	idr_cfg |= priv->synchronous_mode[channel_id];
418 
419 	priv->index_polarity[channel_id] = index_polarity;
420 
421 	/* Load Index Control configuration to Index Control Register */
422 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
423 
424 	mutex_unlock(&priv->lock);
425 
426 	return 0;
427 }
428 
429 static struct counter_signal_enum_ext quad8_index_pol_enum = {
430 	.items = quad8_index_polarity_modes,
431 	.num_items = ARRAY_SIZE(quad8_index_polarity_modes),
432 	.get = quad8_index_polarity_get,
433 	.set = quad8_index_polarity_set
434 };
435 
436 static const char *const quad8_synchronous_modes[] = {
437 	"non-synchronous",
438 	"synchronous"
439 };
440 
441 static int quad8_synchronous_mode_get(struct counter_device *counter,
442 	struct counter_signal *signal, size_t *synchronous_mode)
443 {
444 	const struct quad8 *const priv = counter->priv;
445 	const size_t channel_id = signal->id - 16;
446 
447 	*synchronous_mode = priv->synchronous_mode[channel_id];
448 
449 	return 0;
450 }
451 
452 static int quad8_synchronous_mode_set(struct counter_device *counter,
453 	struct counter_signal *signal, size_t synchronous_mode)
454 {
455 	struct quad8 *const priv = counter->priv;
456 	const size_t channel_id = signal->id - 16;
457 	const int base_offset = priv->base + 2 * channel_id + 1;
458 	unsigned int idr_cfg = synchronous_mode;
459 
460 	mutex_lock(&priv->lock);
461 
462 	idr_cfg |= priv->index_polarity[channel_id] << 1;
463 
464 	/* Index function must be non-synchronous in non-quadrature mode */
465 	if (synchronous_mode && !priv->quadrature_mode[channel_id]) {
466 		mutex_unlock(&priv->lock);
467 		return -EINVAL;
468 	}
469 
470 	priv->synchronous_mode[channel_id] = synchronous_mode;
471 
472 	/* Load Index Control configuration to Index Control Register */
473 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
474 
475 	mutex_unlock(&priv->lock);
476 
477 	return 0;
478 }
479 
480 static struct counter_signal_enum_ext quad8_syn_mode_enum = {
481 	.items = quad8_synchronous_modes,
482 	.num_items = ARRAY_SIZE(quad8_synchronous_modes),
483 	.get = quad8_synchronous_mode_get,
484 	.set = quad8_synchronous_mode_set
485 };
486 
487 static ssize_t quad8_count_floor_read(struct counter_device *counter,
488 	struct counter_count *count, void *private, char *buf)
489 {
490 	/* Only a floor of 0 is supported */
491 	return sprintf(buf, "0\n");
492 }
493 
494 static int quad8_count_mode_get(struct counter_device *counter,
495 	struct counter_count *count, size_t *cnt_mode)
496 {
497 	const struct quad8 *const priv = counter->priv;
498 
499 	/* Map 104-QUAD-8 count mode to Generic Counter count mode */
500 	switch (priv->count_mode[count->id]) {
501 	case 0:
502 		*cnt_mode = COUNTER_COUNT_MODE_NORMAL;
503 		break;
504 	case 1:
505 		*cnt_mode = COUNTER_COUNT_MODE_RANGE_LIMIT;
506 		break;
507 	case 2:
508 		*cnt_mode = COUNTER_COUNT_MODE_NON_RECYCLE;
509 		break;
510 	case 3:
511 		*cnt_mode = COUNTER_COUNT_MODE_MODULO_N;
512 		break;
513 	}
514 
515 	return 0;
516 }
517 
518 static int quad8_count_mode_set(struct counter_device *counter,
519 	struct counter_count *count, size_t cnt_mode)
520 {
521 	struct quad8 *const priv = counter->priv;
522 	unsigned int mode_cfg;
523 	const int base_offset = priv->base + 2 * count->id + 1;
524 
525 	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
526 	switch (cnt_mode) {
527 	case COUNTER_COUNT_MODE_NORMAL:
528 		cnt_mode = 0;
529 		break;
530 	case COUNTER_COUNT_MODE_RANGE_LIMIT:
531 		cnt_mode = 1;
532 		break;
533 	case COUNTER_COUNT_MODE_NON_RECYCLE:
534 		cnt_mode = 2;
535 		break;
536 	case COUNTER_COUNT_MODE_MODULO_N:
537 		cnt_mode = 3;
538 		break;
539 	default:
540 		/* should never reach this path */
541 		return -EINVAL;
542 	}
543 
544 	mutex_lock(&priv->lock);
545 
546 	priv->count_mode[count->id] = cnt_mode;
547 
548 	/* Set count mode configuration value */
549 	mode_cfg = cnt_mode << 1;
550 
551 	/* Add quadrature mode configuration */
552 	if (priv->quadrature_mode[count->id])
553 		mode_cfg |= (priv->quadrature_scale[count->id] + 1) << 3;
554 
555 	/* Load mode configuration to Counter Mode Register */
556 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
557 
558 	mutex_unlock(&priv->lock);
559 
560 	return 0;
561 }
562 
563 static struct counter_count_enum_ext quad8_cnt_mode_enum = {
564 	.items = counter_count_mode_str,
565 	.num_items = ARRAY_SIZE(counter_count_mode_str),
566 	.get = quad8_count_mode_get,
567 	.set = quad8_count_mode_set
568 };
569 
570 static ssize_t quad8_count_direction_read(struct counter_device *counter,
571 	struct counter_count *count, void *priv, char *buf)
572 {
573 	enum counter_count_direction dir;
574 
575 	quad8_direction_get(counter, count, &dir);
576 
577 	return sprintf(buf, "%s\n", counter_count_direction_str[dir]);
578 }
579 
580 static ssize_t quad8_count_enable_read(struct counter_device *counter,
581 	struct counter_count *count, void *private, char *buf)
582 {
583 	const struct quad8 *const priv = counter->priv;
584 
585 	return sprintf(buf, "%u\n", priv->ab_enable[count->id]);
586 }
587 
588 static ssize_t quad8_count_enable_write(struct counter_device *counter,
589 	struct counter_count *count, void *private, const char *buf, size_t len)
590 {
591 	struct quad8 *const priv = counter->priv;
592 	const int base_offset = priv->base + 2 * count->id;
593 	int err;
594 	bool ab_enable;
595 	unsigned int ior_cfg;
596 
597 	err = kstrtobool(buf, &ab_enable);
598 	if (err)
599 		return err;
600 
601 	mutex_lock(&priv->lock);
602 
603 	priv->ab_enable[count->id] = ab_enable;
604 
605 	ior_cfg = ab_enable | priv->preset_enable[count->id] << 1;
606 
607 	/* Load I/O control configuration */
608 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
609 
610 	mutex_unlock(&priv->lock);
611 
612 	return len;
613 }
614 
615 static const char *const quad8_noise_error_states[] = {
616 	"No excessive noise is present at the count inputs",
617 	"Excessive noise is present at the count inputs"
618 };
619 
620 static int quad8_error_noise_get(struct counter_device *counter,
621 	struct counter_count *count, size_t *noise_error)
622 {
623 	const struct quad8 *const priv = counter->priv;
624 	const int base_offset = priv->base + 2 * count->id + 1;
625 
626 	*noise_error = !!(inb(base_offset) & QUAD8_FLAG_E);
627 
628 	return 0;
629 }
630 
631 static struct counter_count_enum_ext quad8_error_noise_enum = {
632 	.items = quad8_noise_error_states,
633 	.num_items = ARRAY_SIZE(quad8_noise_error_states),
634 	.get = quad8_error_noise_get
635 };
636 
637 static ssize_t quad8_count_preset_read(struct counter_device *counter,
638 	struct counter_count *count, void *private, char *buf)
639 {
640 	const struct quad8 *const priv = counter->priv;
641 
642 	return sprintf(buf, "%u\n", priv->preset[count->id]);
643 }
644 
645 static void quad8_preset_register_set(struct quad8 *const priv, const int id,
646 				      const unsigned int preset)
647 {
648 	const unsigned int base_offset = priv->base + 2 * id;
649 	int i;
650 
651 	priv->preset[id] = preset;
652 
653 	/* Reset Byte Pointer */
654 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
655 
656 	/* Set Preset Register */
657 	for (i = 0; i < 3; i++)
658 		outb(preset >> (8 * i), base_offset);
659 }
660 
661 static ssize_t quad8_count_preset_write(struct counter_device *counter,
662 	struct counter_count *count, void *private, const char *buf, size_t len)
663 {
664 	struct quad8 *const priv = counter->priv;
665 	unsigned int preset;
666 	int ret;
667 
668 	ret = kstrtouint(buf, 0, &preset);
669 	if (ret)
670 		return ret;
671 
672 	/* Only 24-bit values are supported */
673 	if (preset > 0xFFFFFF)
674 		return -ERANGE;
675 
676 	mutex_lock(&priv->lock);
677 
678 	quad8_preset_register_set(priv, count->id, preset);
679 
680 	mutex_unlock(&priv->lock);
681 
682 	return len;
683 }
684 
685 static ssize_t quad8_count_ceiling_read(struct counter_device *counter,
686 	struct counter_count *count, void *private, char *buf)
687 {
688 	struct quad8 *const priv = counter->priv;
689 
690 	mutex_lock(&priv->lock);
691 
692 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
693 	switch (priv->count_mode[count->id]) {
694 	case 1:
695 	case 3:
696 		mutex_unlock(&priv->lock);
697 		return sprintf(buf, "%u\n", priv->preset[count->id]);
698 	}
699 
700 	mutex_unlock(&priv->lock);
701 
702 	/* By default 0x1FFFFFF (25 bits unsigned) is maximum count */
703 	return sprintf(buf, "33554431\n");
704 }
705 
706 static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
707 	struct counter_count *count, void *private, const char *buf, size_t len)
708 {
709 	struct quad8 *const priv = counter->priv;
710 	unsigned int ceiling;
711 	int ret;
712 
713 	ret = kstrtouint(buf, 0, &ceiling);
714 	if (ret)
715 		return ret;
716 
717 	/* Only 24-bit values are supported */
718 	if (ceiling > 0xFFFFFF)
719 		return -ERANGE;
720 
721 	mutex_lock(&priv->lock);
722 
723 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
724 	switch (priv->count_mode[count->id]) {
725 	case 1:
726 	case 3:
727 		quad8_preset_register_set(priv, count->id, ceiling);
728 		mutex_unlock(&priv->lock);
729 		return len;
730 	}
731 
732 	mutex_unlock(&priv->lock);
733 
734 	return -EINVAL;
735 }
736 
737 static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,
738 	struct counter_count *count, void *private, char *buf)
739 {
740 	const struct quad8 *const priv = counter->priv;
741 
742 	return sprintf(buf, "%u\n", !priv->preset_enable[count->id]);
743 }
744 
745 static ssize_t quad8_count_preset_enable_write(struct counter_device *counter,
746 	struct counter_count *count, void *private, const char *buf, size_t len)
747 {
748 	struct quad8 *const priv = counter->priv;
749 	const int base_offset = priv->base + 2 * count->id + 1;
750 	bool preset_enable;
751 	int ret;
752 	unsigned int ior_cfg;
753 
754 	ret = kstrtobool(buf, &preset_enable);
755 	if (ret)
756 		return ret;
757 
758 	/* Preset enable is active low in Input/Output Control register */
759 	preset_enable = !preset_enable;
760 
761 	mutex_lock(&priv->lock);
762 
763 	priv->preset_enable[count->id] = preset_enable;
764 
765 	ior_cfg = priv->ab_enable[count->id] | (unsigned int)preset_enable << 1;
766 
767 	/* Load I/O control configuration to Input / Output Control Register */
768 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
769 
770 	mutex_unlock(&priv->lock);
771 
772 	return len;
773 }
774 
775 static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter,
776 					     struct counter_signal *signal,
777 					     void *private, char *buf)
778 {
779 	struct quad8 *const priv = counter->priv;
780 	const size_t channel_id = signal->id / 2;
781 	bool disabled;
782 	unsigned int status;
783 	unsigned int fault;
784 
785 	mutex_lock(&priv->lock);
786 
787 	disabled = !(priv->cable_fault_enable & BIT(channel_id));
788 
789 	if (disabled) {
790 		mutex_unlock(&priv->lock);
791 		return -EINVAL;
792 	}
793 
794 	/* Logic 0 = cable fault */
795 	status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
796 
797 	mutex_unlock(&priv->lock);
798 
799 	/* Mask respective channel and invert logic */
800 	fault = !(status & BIT(channel_id));
801 
802 	return sprintf(buf, "%u\n", fault);
803 }
804 
805 static ssize_t quad8_signal_cable_fault_enable_read(
806 	struct counter_device *counter, struct counter_signal *signal,
807 	void *private, char *buf)
808 {
809 	const struct quad8 *const priv = counter->priv;
810 	const size_t channel_id = signal->id / 2;
811 	const unsigned int enb = !!(priv->cable_fault_enable & BIT(channel_id));
812 
813 	return sprintf(buf, "%u\n", enb);
814 }
815 
816 static ssize_t quad8_signal_cable_fault_enable_write(
817 	struct counter_device *counter, struct counter_signal *signal,
818 	void *private, const char *buf, size_t len)
819 {
820 	struct quad8 *const priv = counter->priv;
821 	const size_t channel_id = signal->id / 2;
822 	bool enable;
823 	int ret;
824 	unsigned int cable_fault_enable;
825 
826 	ret = kstrtobool(buf, &enable);
827 	if (ret)
828 		return ret;
829 
830 	mutex_lock(&priv->lock);
831 
832 	if (enable)
833 		priv->cable_fault_enable |= BIT(channel_id);
834 	else
835 		priv->cable_fault_enable &= ~BIT(channel_id);
836 
837 	/* Enable is active low in Differential Encoder Cable Status register */
838 	cable_fault_enable = ~priv->cable_fault_enable;
839 
840 	outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
841 
842 	mutex_unlock(&priv->lock);
843 
844 	return len;
845 }
846 
847 static ssize_t quad8_signal_fck_prescaler_read(struct counter_device *counter,
848 	struct counter_signal *signal, void *private, char *buf)
849 {
850 	const struct quad8 *const priv = counter->priv;
851 	const size_t channel_id = signal->id / 2;
852 
853 	return sprintf(buf, "%u\n", priv->fck_prescaler[channel_id]);
854 }
855 
856 static ssize_t quad8_signal_fck_prescaler_write(struct counter_device *counter,
857 	struct counter_signal *signal, void *private, const char *buf,
858 	size_t len)
859 {
860 	struct quad8 *const priv = counter->priv;
861 	const size_t channel_id = signal->id / 2;
862 	const int base_offset = priv->base + 2 * channel_id;
863 	u8 prescaler;
864 	int ret;
865 
866 	ret = kstrtou8(buf, 0, &prescaler);
867 	if (ret)
868 		return ret;
869 
870 	mutex_lock(&priv->lock);
871 
872 	priv->fck_prescaler[channel_id] = prescaler;
873 
874 	/* Reset Byte Pointer */
875 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
876 
877 	/* Set filter clock factor */
878 	outb(prescaler, base_offset);
879 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
880 	     base_offset + 1);
881 
882 	mutex_unlock(&priv->lock);
883 
884 	return len;
885 }
886 
887 static const struct counter_signal_ext quad8_signal_ext[] = {
888 	{
889 		.name = "cable_fault",
890 		.read = quad8_signal_cable_fault_read
891 	},
892 	{
893 		.name = "cable_fault_enable",
894 		.read = quad8_signal_cable_fault_enable_read,
895 		.write = quad8_signal_cable_fault_enable_write
896 	},
897 	{
898 		.name = "filter_clock_prescaler",
899 		.read = quad8_signal_fck_prescaler_read,
900 		.write = quad8_signal_fck_prescaler_write
901 	}
902 };
903 
904 static const struct counter_signal_ext quad8_index_ext[] = {
905 	COUNTER_SIGNAL_ENUM("index_polarity", &quad8_index_pol_enum),
906 	COUNTER_SIGNAL_ENUM_AVAILABLE("index_polarity",	&quad8_index_pol_enum),
907 	COUNTER_SIGNAL_ENUM("synchronous_mode", &quad8_syn_mode_enum),
908 	COUNTER_SIGNAL_ENUM_AVAILABLE("synchronous_mode", &quad8_syn_mode_enum)
909 };
910 
911 #define QUAD8_QUAD_SIGNAL(_id, _name) {		\
912 	.id = (_id),				\
913 	.name = (_name),			\
914 	.ext = quad8_signal_ext,		\
915 	.num_ext = ARRAY_SIZE(quad8_signal_ext)	\
916 }
917 
918 #define	QUAD8_INDEX_SIGNAL(_id, _name) {	\
919 	.id = (_id),				\
920 	.name = (_name),			\
921 	.ext = quad8_index_ext,			\
922 	.num_ext = ARRAY_SIZE(quad8_index_ext)	\
923 }
924 
925 static struct counter_signal quad8_signals[] = {
926 	QUAD8_QUAD_SIGNAL(0, "Channel 1 Quadrature A"),
927 	QUAD8_QUAD_SIGNAL(1, "Channel 1 Quadrature B"),
928 	QUAD8_QUAD_SIGNAL(2, "Channel 2 Quadrature A"),
929 	QUAD8_QUAD_SIGNAL(3, "Channel 2 Quadrature B"),
930 	QUAD8_QUAD_SIGNAL(4, "Channel 3 Quadrature A"),
931 	QUAD8_QUAD_SIGNAL(5, "Channel 3 Quadrature B"),
932 	QUAD8_QUAD_SIGNAL(6, "Channel 4 Quadrature A"),
933 	QUAD8_QUAD_SIGNAL(7, "Channel 4 Quadrature B"),
934 	QUAD8_QUAD_SIGNAL(8, "Channel 5 Quadrature A"),
935 	QUAD8_QUAD_SIGNAL(9, "Channel 5 Quadrature B"),
936 	QUAD8_QUAD_SIGNAL(10, "Channel 6 Quadrature A"),
937 	QUAD8_QUAD_SIGNAL(11, "Channel 6 Quadrature B"),
938 	QUAD8_QUAD_SIGNAL(12, "Channel 7 Quadrature A"),
939 	QUAD8_QUAD_SIGNAL(13, "Channel 7 Quadrature B"),
940 	QUAD8_QUAD_SIGNAL(14, "Channel 8 Quadrature A"),
941 	QUAD8_QUAD_SIGNAL(15, "Channel 8 Quadrature B"),
942 	QUAD8_INDEX_SIGNAL(16, "Channel 1 Index"),
943 	QUAD8_INDEX_SIGNAL(17, "Channel 2 Index"),
944 	QUAD8_INDEX_SIGNAL(18, "Channel 3 Index"),
945 	QUAD8_INDEX_SIGNAL(19, "Channel 4 Index"),
946 	QUAD8_INDEX_SIGNAL(20, "Channel 5 Index"),
947 	QUAD8_INDEX_SIGNAL(21, "Channel 6 Index"),
948 	QUAD8_INDEX_SIGNAL(22, "Channel 7 Index"),
949 	QUAD8_INDEX_SIGNAL(23, "Channel 8 Index")
950 };
951 
952 #define QUAD8_COUNT_SYNAPSES(_id) {					\
953 	{								\
954 		.actions_list = quad8_synapse_actions_list,		\
955 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
956 		.signal = quad8_signals + 2 * (_id)			\
957 	},								\
958 	{								\
959 		.actions_list = quad8_synapse_actions_list,		\
960 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
961 		.signal = quad8_signals + 2 * (_id) + 1			\
962 	},								\
963 	{								\
964 		.actions_list = quad8_index_actions_list,		\
965 		.num_actions = ARRAY_SIZE(quad8_index_actions_list),	\
966 		.signal = quad8_signals + 2 * (_id) + 16		\
967 	}								\
968 }
969 
970 static struct counter_synapse quad8_count_synapses[][3] = {
971 	QUAD8_COUNT_SYNAPSES(0), QUAD8_COUNT_SYNAPSES(1),
972 	QUAD8_COUNT_SYNAPSES(2), QUAD8_COUNT_SYNAPSES(3),
973 	QUAD8_COUNT_SYNAPSES(4), QUAD8_COUNT_SYNAPSES(5),
974 	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
975 };
976 
977 static const struct counter_count_ext quad8_count_ext[] = {
978 	{
979 		.name = "ceiling",
980 		.read = quad8_count_ceiling_read,
981 		.write = quad8_count_ceiling_write
982 	},
983 	{
984 		.name = "floor",
985 		.read = quad8_count_floor_read
986 	},
987 	COUNTER_COUNT_ENUM("count_mode", &quad8_cnt_mode_enum),
988 	COUNTER_COUNT_ENUM_AVAILABLE("count_mode", &quad8_cnt_mode_enum),
989 	{
990 		.name = "direction",
991 		.read = quad8_count_direction_read
992 	},
993 	{
994 		.name = "enable",
995 		.read = quad8_count_enable_read,
996 		.write = quad8_count_enable_write
997 	},
998 	COUNTER_COUNT_ENUM("error_noise", &quad8_error_noise_enum),
999 	COUNTER_COUNT_ENUM_AVAILABLE("error_noise", &quad8_error_noise_enum),
1000 	{
1001 		.name = "preset",
1002 		.read = quad8_count_preset_read,
1003 		.write = quad8_count_preset_write
1004 	},
1005 	{
1006 		.name = "preset_enable",
1007 		.read = quad8_count_preset_enable_read,
1008 		.write = quad8_count_preset_enable_write
1009 	}
1010 };
1011 
1012 #define QUAD8_COUNT(_id, _cntname) {					\
1013 	.id = (_id),							\
1014 	.name = (_cntname),						\
1015 	.functions_list = quad8_count_functions_list,			\
1016 	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
1017 	.synapses = quad8_count_synapses[(_id)],			\
1018 	.num_synapses =	2,						\
1019 	.ext = quad8_count_ext,						\
1020 	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
1021 }
1022 
1023 static struct counter_count quad8_counts[] = {
1024 	QUAD8_COUNT(0, "Channel 1 Count"),
1025 	QUAD8_COUNT(1, "Channel 2 Count"),
1026 	QUAD8_COUNT(2, "Channel 3 Count"),
1027 	QUAD8_COUNT(3, "Channel 4 Count"),
1028 	QUAD8_COUNT(4, "Channel 5 Count"),
1029 	QUAD8_COUNT(5, "Channel 6 Count"),
1030 	QUAD8_COUNT(6, "Channel 7 Count"),
1031 	QUAD8_COUNT(7, "Channel 8 Count")
1032 };
1033 
1034 static int quad8_probe(struct device *dev, unsigned int id)
1035 {
1036 	struct quad8 *priv;
1037 	int i, j;
1038 	unsigned int base_offset;
1039 
1040 	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
1041 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
1042 			base[id], base[id] + QUAD8_EXTENT);
1043 		return -EBUSY;
1044 	}
1045 
1046 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
1047 	if (!priv)
1048 		return -ENOMEM;
1049 
1050 	/* Initialize Counter device and driver data */
1051 	priv->counter.name = dev_name(dev);
1052 	priv->counter.parent = dev;
1053 	priv->counter.ops = &quad8_ops;
1054 	priv->counter.counts = quad8_counts;
1055 	priv->counter.num_counts = ARRAY_SIZE(quad8_counts);
1056 	priv->counter.signals = quad8_signals;
1057 	priv->counter.num_signals = ARRAY_SIZE(quad8_signals);
1058 	priv->counter.priv = priv;
1059 	priv->base = base[id];
1060 
1061 	/* Initialize mutex */
1062 	mutex_init(&priv->lock);
1063 
1064 	/* Reset all counters and disable interrupt function */
1065 	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
1066 	/* Set initial configuration for all counters */
1067 	for (i = 0; i < QUAD8_NUM_COUNTERS; i++) {
1068 		base_offset = base[id] + 2 * i;
1069 		/* Reset Byte Pointer */
1070 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
1071 		/* Reset filter clock factor */
1072 		outb(0, base_offset);
1073 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
1074 		     base_offset + 1);
1075 		/* Reset Byte Pointer */
1076 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
1077 		/* Reset Preset Register */
1078 		for (j = 0; j < 3; j++)
1079 			outb(0x00, base_offset);
1080 		/* Reset Borrow, Carry, Compare, and Sign flags */
1081 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
1082 		/* Reset Error flag */
1083 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
1084 		/* Binary encoding; Normal count; non-quadrature mode */
1085 		outb(QUAD8_CTR_CMR, base_offset + 1);
1086 		/* Disable A and B inputs; preset on index; FLG1 as Carry */
1087 		outb(QUAD8_CTR_IOR, base_offset + 1);
1088 		/* Disable index function; negative index polarity */
1089 		outb(QUAD8_CTR_IDR, base_offset + 1);
1090 	}
1091 	/* Disable Differential Encoder Cable Status for all channels */
1092 	outb(0xFF, base[id] + QUAD8_DIFF_ENCODER_CABLE_STATUS);
1093 	/* Enable all counters */
1094 	outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
1095 
1096 	return devm_counter_register(dev, &priv->counter);
1097 }
1098 
1099 static struct isa_driver quad8_driver = {
1100 	.probe = quad8_probe,
1101 	.driver = {
1102 		.name = "104-quad-8"
1103 	}
1104 };
1105 
1106 module_isa_driver(quad8_driver, num_quad8);
1107 
1108 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
1109 MODULE_DESCRIPTION("ACCES 104-QUAD-8 driver");
1110 MODULE_LICENSE("GPL v2");
1111