xref: /openbmc/linux/drivers/counter/104-quad-8.c (revision 15e3ae36)
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/iio/iio.h>
13 #include <linux/iio/types.h>
14 #include <linux/io.h>
15 #include <linux/ioport.h>
16 #include <linux/isa.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/types.h>
21 
22 #define QUAD8_EXTENT 32
23 
24 static unsigned int base[max_num_isa_dev(QUAD8_EXTENT)];
25 static unsigned int num_quad8;
26 module_param_array(base, uint, &num_quad8, 0);
27 MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
28 
29 #define QUAD8_NUM_COUNTERS 8
30 
31 /**
32  * struct quad8_iio - IIO device private data structure
33  * @counter:		instance of the counter_device
34  * @fck_prescaler:	array of filter clock prescaler configurations
35  * @preset:		array of preset values
36  * @count_mode:		array of count mode configurations
37  * @quadrature_mode:	array of quadrature mode configurations
38  * @quadrature_scale:	array of quadrature mode scale configurations
39  * @ab_enable:		array of A and B inputs enable configurations
40  * @preset_enable:	array of set_to_preset_on_index attribute configurations
41  * @synchronous_mode:	array of index function synchronous mode configurations
42  * @index_polarity:	array of index function polarity configurations
43  * @cable_fault_enable:	differential encoder cable status enable configurations
44  * @base:		base port address of the IIO device
45  */
46 struct quad8_iio {
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 
101 static int quad8_read_raw(struct iio_dev *indio_dev,
102 	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
103 {
104 	struct quad8_iio *const priv = iio_priv(indio_dev);
105 	const int base_offset = priv->base + 2 * chan->channel;
106 	unsigned int flags;
107 	unsigned int borrow;
108 	unsigned int carry;
109 	int i;
110 
111 	switch (mask) {
112 	case IIO_CHAN_INFO_RAW:
113 		if (chan->type == IIO_INDEX) {
114 			*val = !!(inb(priv->base + QUAD8_REG_INDEX_INPUT_LEVELS)
115 				& BIT(chan->channel));
116 			return IIO_VAL_INT;
117 		}
118 
119 		flags = inb(base_offset + 1);
120 		borrow = flags & QUAD8_FLAG_BT;
121 		carry = !!(flags & QUAD8_FLAG_CT);
122 
123 		/* Borrow XOR Carry effectively doubles count range */
124 		*val = (borrow ^ carry) << 24;
125 
126 		/* Reset Byte Pointer; transfer Counter to Output Latch */
127 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
128 		     base_offset + 1);
129 
130 		for (i = 0; i < 3; i++)
131 			*val |= (unsigned int)inb(base_offset) << (8 * i);
132 
133 		return IIO_VAL_INT;
134 	case IIO_CHAN_INFO_ENABLE:
135 		*val = priv->ab_enable[chan->channel];
136 		return IIO_VAL_INT;
137 	case IIO_CHAN_INFO_SCALE:
138 		*val = 1;
139 		*val2 = priv->quadrature_scale[chan->channel];
140 		return IIO_VAL_FRACTIONAL_LOG2;
141 	}
142 
143 	return -EINVAL;
144 }
145 
146 static int quad8_write_raw(struct iio_dev *indio_dev,
147 	struct iio_chan_spec const *chan, int val, int val2, long mask)
148 {
149 	struct quad8_iio *const priv = iio_priv(indio_dev);
150 	const int base_offset = priv->base + 2 * chan->channel;
151 	int i;
152 	unsigned int ior_cfg;
153 
154 	switch (mask) {
155 	case IIO_CHAN_INFO_RAW:
156 		if (chan->type == IIO_INDEX)
157 			return -EINVAL;
158 
159 		/* Only 24-bit values are supported */
160 		if ((unsigned int)val > 0xFFFFFF)
161 			return -EINVAL;
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[chan->channel];
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 		return 0;
187 	case IIO_CHAN_INFO_ENABLE:
188 		/* only boolean values accepted */
189 		if (val < 0 || val > 1)
190 			return -EINVAL;
191 
192 		priv->ab_enable[chan->channel] = val;
193 
194 		ior_cfg = val | priv->preset_enable[chan->channel] << 1;
195 
196 		/* Load I/O control configuration */
197 		outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
198 
199 		return 0;
200 	case IIO_CHAN_INFO_SCALE:
201 		/* Quadrature scaling only available in quadrature mode */
202 		if (!priv->quadrature_mode[chan->channel] && (val2 || val != 1))
203 			return -EINVAL;
204 
205 		/* Only three gain states (1, 0.5, 0.25) */
206 		if (val == 1 && !val2)
207 			priv->quadrature_scale[chan->channel] = 0;
208 		else if (!val)
209 			switch (val2) {
210 			case 500000:
211 				priv->quadrature_scale[chan->channel] = 1;
212 				break;
213 			case 250000:
214 				priv->quadrature_scale[chan->channel] = 2;
215 				break;
216 			default:
217 				return -EINVAL;
218 			}
219 		else
220 			return -EINVAL;
221 
222 		return 0;
223 	}
224 
225 	return -EINVAL;
226 }
227 
228 static const struct iio_info quad8_info = {
229 	.read_raw = quad8_read_raw,
230 	.write_raw = quad8_write_raw
231 };
232 
233 static ssize_t quad8_read_preset(struct iio_dev *indio_dev, uintptr_t private,
234 	const struct iio_chan_spec *chan, char *buf)
235 {
236 	const struct quad8_iio *const priv = iio_priv(indio_dev);
237 
238 	return snprintf(buf, PAGE_SIZE, "%u\n", priv->preset[chan->channel]);
239 }
240 
241 static ssize_t quad8_write_preset(struct iio_dev *indio_dev, uintptr_t private,
242 	const struct iio_chan_spec *chan, const char *buf, size_t len)
243 {
244 	struct quad8_iio *const priv = iio_priv(indio_dev);
245 	const int base_offset = priv->base + 2 * chan->channel;
246 	unsigned int preset;
247 	int ret;
248 	int i;
249 
250 	ret = kstrtouint(buf, 0, &preset);
251 	if (ret)
252 		return ret;
253 
254 	/* Only 24-bit values are supported */
255 	if (preset > 0xFFFFFF)
256 		return -EINVAL;
257 
258 	priv->preset[chan->channel] = preset;
259 
260 	/* Reset Byte Pointer */
261 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
262 
263 	/* Set Preset Register */
264 	for (i = 0; i < 3; i++)
265 		outb(preset >> (8 * i), base_offset);
266 
267 	return len;
268 }
269 
270 static ssize_t quad8_read_set_to_preset_on_index(struct iio_dev *indio_dev,
271 	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
272 {
273 	const struct quad8_iio *const priv = iio_priv(indio_dev);
274 
275 	return snprintf(buf, PAGE_SIZE, "%u\n",
276 		!priv->preset_enable[chan->channel]);
277 }
278 
279 static ssize_t quad8_write_set_to_preset_on_index(struct iio_dev *indio_dev,
280 	uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
281 	size_t len)
282 {
283 	struct quad8_iio *const priv = iio_priv(indio_dev);
284 	const int base_offset = priv->base + 2 * chan->channel + 1;
285 	bool preset_enable;
286 	int ret;
287 	unsigned int ior_cfg;
288 
289 	ret = kstrtobool(buf, &preset_enable);
290 	if (ret)
291 		return ret;
292 
293 	/* Preset enable is active low in Input/Output Control register */
294 	preset_enable = !preset_enable;
295 
296 	priv->preset_enable[chan->channel] = preset_enable;
297 
298 	ior_cfg = priv->ab_enable[chan->channel] |
299 		(unsigned int)preset_enable << 1;
300 
301 	/* Load I/O control configuration to Input / Output Control Register */
302 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
303 
304 	return len;
305 }
306 
307 static const char *const quad8_noise_error_states[] = {
308 	"No excessive noise is present at the count inputs",
309 	"Excessive noise is present at the count inputs"
310 };
311 
312 static int quad8_get_noise_error(struct iio_dev *indio_dev,
313 	const struct iio_chan_spec *chan)
314 {
315 	struct quad8_iio *const priv = iio_priv(indio_dev);
316 	const int base_offset = priv->base + 2 * chan->channel + 1;
317 
318 	return !!(inb(base_offset) & QUAD8_FLAG_E);
319 }
320 
321 static const struct iio_enum quad8_noise_error_enum = {
322 	.items = quad8_noise_error_states,
323 	.num_items = ARRAY_SIZE(quad8_noise_error_states),
324 	.get = quad8_get_noise_error
325 };
326 
327 static const char *const quad8_count_direction_states[] = {
328 	"down",
329 	"up"
330 };
331 
332 static int quad8_get_count_direction(struct iio_dev *indio_dev,
333 	const struct iio_chan_spec *chan)
334 {
335 	struct quad8_iio *const priv = iio_priv(indio_dev);
336 	const int base_offset = priv->base + 2 * chan->channel + 1;
337 
338 	return !!(inb(base_offset) & QUAD8_FLAG_UD);
339 }
340 
341 static const struct iio_enum quad8_count_direction_enum = {
342 	.items = quad8_count_direction_states,
343 	.num_items = ARRAY_SIZE(quad8_count_direction_states),
344 	.get = quad8_get_count_direction
345 };
346 
347 static const char *const quad8_count_modes[] = {
348 	"normal",
349 	"range limit",
350 	"non-recycle",
351 	"modulo-n"
352 };
353 
354 static int quad8_set_count_mode(struct iio_dev *indio_dev,
355 	const struct iio_chan_spec *chan, unsigned int cnt_mode)
356 {
357 	struct quad8_iio *const priv = iio_priv(indio_dev);
358 	unsigned int mode_cfg = cnt_mode << 1;
359 	const int base_offset = priv->base + 2 * chan->channel + 1;
360 
361 	priv->count_mode[chan->channel] = cnt_mode;
362 
363 	/* Add quadrature mode configuration */
364 	if (priv->quadrature_mode[chan->channel])
365 		mode_cfg |= (priv->quadrature_scale[chan->channel] + 1) << 3;
366 
367 	/* Load mode configuration to Counter Mode Register */
368 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
369 
370 	return 0;
371 }
372 
373 static int quad8_get_count_mode(struct iio_dev *indio_dev,
374 	const struct iio_chan_spec *chan)
375 {
376 	const struct quad8_iio *const priv = iio_priv(indio_dev);
377 
378 	return priv->count_mode[chan->channel];
379 }
380 
381 static const struct iio_enum quad8_count_mode_enum = {
382 	.items = quad8_count_modes,
383 	.num_items = ARRAY_SIZE(quad8_count_modes),
384 	.set = quad8_set_count_mode,
385 	.get = quad8_get_count_mode
386 };
387 
388 static const char *const quad8_synchronous_modes[] = {
389 	"non-synchronous",
390 	"synchronous"
391 };
392 
393 static int quad8_set_synchronous_mode(struct iio_dev *indio_dev,
394 	const struct iio_chan_spec *chan, unsigned int synchronous_mode)
395 {
396 	struct quad8_iio *const priv = iio_priv(indio_dev);
397 	const unsigned int idr_cfg = synchronous_mode |
398 		priv->index_polarity[chan->channel] << 1;
399 	const int base_offset = priv->base + 2 * chan->channel + 1;
400 
401 	/* Index function must be non-synchronous in non-quadrature mode */
402 	if (synchronous_mode && !priv->quadrature_mode[chan->channel])
403 		return -EINVAL;
404 
405 	priv->synchronous_mode[chan->channel] = synchronous_mode;
406 
407 	/* Load Index Control configuration to Index Control Register */
408 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
409 
410 	return 0;
411 }
412 
413 static int quad8_get_synchronous_mode(struct iio_dev *indio_dev,
414 	const struct iio_chan_spec *chan)
415 {
416 	const struct quad8_iio *const priv = iio_priv(indio_dev);
417 
418 	return priv->synchronous_mode[chan->channel];
419 }
420 
421 static const struct iio_enum quad8_synchronous_mode_enum = {
422 	.items = quad8_synchronous_modes,
423 	.num_items = ARRAY_SIZE(quad8_synchronous_modes),
424 	.set = quad8_set_synchronous_mode,
425 	.get = quad8_get_synchronous_mode
426 };
427 
428 static const char *const quad8_quadrature_modes[] = {
429 	"non-quadrature",
430 	"quadrature"
431 };
432 
433 static int quad8_set_quadrature_mode(struct iio_dev *indio_dev,
434 	const struct iio_chan_spec *chan, unsigned int quadrature_mode)
435 {
436 	struct quad8_iio *const priv = iio_priv(indio_dev);
437 	unsigned int mode_cfg = priv->count_mode[chan->channel] << 1;
438 	const int base_offset = priv->base + 2 * chan->channel + 1;
439 
440 	if (quadrature_mode)
441 		mode_cfg |= (priv->quadrature_scale[chan->channel] + 1) << 3;
442 	else {
443 		/* Quadrature scaling only available in quadrature mode */
444 		priv->quadrature_scale[chan->channel] = 0;
445 
446 		/* Synchronous function not supported in non-quadrature mode */
447 		if (priv->synchronous_mode[chan->channel])
448 			quad8_set_synchronous_mode(indio_dev, chan, 0);
449 	}
450 
451 	priv->quadrature_mode[chan->channel] = quadrature_mode;
452 
453 	/* Load mode configuration to Counter Mode Register */
454 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
455 
456 	return 0;
457 }
458 
459 static int quad8_get_quadrature_mode(struct iio_dev *indio_dev,
460 	const struct iio_chan_spec *chan)
461 {
462 	const struct quad8_iio *const priv = iio_priv(indio_dev);
463 
464 	return priv->quadrature_mode[chan->channel];
465 }
466 
467 static const struct iio_enum quad8_quadrature_mode_enum = {
468 	.items = quad8_quadrature_modes,
469 	.num_items = ARRAY_SIZE(quad8_quadrature_modes),
470 	.set = quad8_set_quadrature_mode,
471 	.get = quad8_get_quadrature_mode
472 };
473 
474 static const char *const quad8_index_polarity_modes[] = {
475 	"negative",
476 	"positive"
477 };
478 
479 static int quad8_set_index_polarity(struct iio_dev *indio_dev,
480 	const struct iio_chan_spec *chan, unsigned int index_polarity)
481 {
482 	struct quad8_iio *const priv = iio_priv(indio_dev);
483 	const unsigned int idr_cfg = priv->synchronous_mode[chan->channel] |
484 		index_polarity << 1;
485 	const int base_offset = priv->base + 2 * chan->channel + 1;
486 
487 	priv->index_polarity[chan->channel] = index_polarity;
488 
489 	/* Load Index Control configuration to Index Control Register */
490 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
491 
492 	return 0;
493 }
494 
495 static int quad8_get_index_polarity(struct iio_dev *indio_dev,
496 	const struct iio_chan_spec *chan)
497 {
498 	const struct quad8_iio *const priv = iio_priv(indio_dev);
499 
500 	return priv->index_polarity[chan->channel];
501 }
502 
503 static const struct iio_enum quad8_index_polarity_enum = {
504 	.items = quad8_index_polarity_modes,
505 	.num_items = ARRAY_SIZE(quad8_index_polarity_modes),
506 	.set = quad8_set_index_polarity,
507 	.get = quad8_get_index_polarity
508 };
509 
510 static const struct iio_chan_spec_ext_info quad8_count_ext_info[] = {
511 	{
512 		.name = "preset",
513 		.shared = IIO_SEPARATE,
514 		.read = quad8_read_preset,
515 		.write = quad8_write_preset
516 	},
517 	{
518 		.name = "set_to_preset_on_index",
519 		.shared = IIO_SEPARATE,
520 		.read = quad8_read_set_to_preset_on_index,
521 		.write = quad8_write_set_to_preset_on_index
522 	},
523 	IIO_ENUM("noise_error", IIO_SEPARATE, &quad8_noise_error_enum),
524 	IIO_ENUM_AVAILABLE("noise_error", &quad8_noise_error_enum),
525 	IIO_ENUM("count_direction", IIO_SEPARATE, &quad8_count_direction_enum),
526 	IIO_ENUM_AVAILABLE("count_direction", &quad8_count_direction_enum),
527 	IIO_ENUM("count_mode", IIO_SEPARATE, &quad8_count_mode_enum),
528 	IIO_ENUM_AVAILABLE("count_mode", &quad8_count_mode_enum),
529 	IIO_ENUM("quadrature_mode", IIO_SEPARATE, &quad8_quadrature_mode_enum),
530 	IIO_ENUM_AVAILABLE("quadrature_mode", &quad8_quadrature_mode_enum),
531 	{}
532 };
533 
534 static const struct iio_chan_spec_ext_info quad8_index_ext_info[] = {
535 	IIO_ENUM("synchronous_mode", IIO_SEPARATE,
536 		&quad8_synchronous_mode_enum),
537 	IIO_ENUM_AVAILABLE("synchronous_mode", &quad8_synchronous_mode_enum),
538 	IIO_ENUM("index_polarity", IIO_SEPARATE, &quad8_index_polarity_enum),
539 	IIO_ENUM_AVAILABLE("index_polarity", &quad8_index_polarity_enum),
540 	{}
541 };
542 
543 #define QUAD8_COUNT_CHAN(_chan) {					\
544 	.type = IIO_COUNT,						\
545 	.channel = (_chan),						\
546 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |			\
547 		BIT(IIO_CHAN_INFO_ENABLE) | BIT(IIO_CHAN_INFO_SCALE),	\
548 	.ext_info = quad8_count_ext_info,				\
549 	.indexed = 1							\
550 }
551 
552 #define QUAD8_INDEX_CHAN(_chan) {			\
553 	.type = IIO_INDEX,				\
554 	.channel = (_chan),				\
555 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
556 	.ext_info = quad8_index_ext_info,		\
557 	.indexed = 1					\
558 }
559 
560 static const struct iio_chan_spec quad8_channels[] = {
561 	QUAD8_COUNT_CHAN(0), QUAD8_INDEX_CHAN(0),
562 	QUAD8_COUNT_CHAN(1), QUAD8_INDEX_CHAN(1),
563 	QUAD8_COUNT_CHAN(2), QUAD8_INDEX_CHAN(2),
564 	QUAD8_COUNT_CHAN(3), QUAD8_INDEX_CHAN(3),
565 	QUAD8_COUNT_CHAN(4), QUAD8_INDEX_CHAN(4),
566 	QUAD8_COUNT_CHAN(5), QUAD8_INDEX_CHAN(5),
567 	QUAD8_COUNT_CHAN(6), QUAD8_INDEX_CHAN(6),
568 	QUAD8_COUNT_CHAN(7), QUAD8_INDEX_CHAN(7)
569 };
570 
571 static int quad8_signal_read(struct counter_device *counter,
572 	struct counter_signal *signal, enum counter_signal_value *val)
573 {
574 	const struct quad8_iio *const priv = counter->priv;
575 	unsigned int state;
576 
577 	/* Only Index signal levels can be read */
578 	if (signal->id < 16)
579 		return -EINVAL;
580 
581 	state = inb(priv->base + QUAD8_REG_INDEX_INPUT_LEVELS)
582 		& BIT(signal->id - 16);
583 
584 	*val = (state) ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
585 
586 	return 0;
587 }
588 
589 static int quad8_count_read(struct counter_device *counter,
590 	struct counter_count *count, unsigned long *val)
591 {
592 	const struct quad8_iio *const priv = counter->priv;
593 	const int base_offset = priv->base + 2 * count->id;
594 	unsigned int flags;
595 	unsigned int borrow;
596 	unsigned int carry;
597 	int i;
598 
599 	flags = inb(base_offset + 1);
600 	borrow = flags & QUAD8_FLAG_BT;
601 	carry = !!(flags & QUAD8_FLAG_CT);
602 
603 	/* Borrow XOR Carry effectively doubles count range */
604 	*val = (unsigned long)(borrow ^ carry) << 24;
605 
606 	/* Reset Byte Pointer; transfer Counter to Output Latch */
607 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
608 	     base_offset + 1);
609 
610 	for (i = 0; i < 3; i++)
611 		*val |= (unsigned long)inb(base_offset) << (8 * i);
612 
613 	return 0;
614 }
615 
616 static int quad8_count_write(struct counter_device *counter,
617 	struct counter_count *count, unsigned long val)
618 {
619 	const struct quad8_iio *const priv = counter->priv;
620 	const int base_offset = priv->base + 2 * count->id;
621 	int i;
622 
623 	/* Only 24-bit values are supported */
624 	if (val > 0xFFFFFF)
625 		return -EINVAL;
626 
627 	/* Reset Byte Pointer */
628 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
629 
630 	/* Counter can only be set via Preset Register */
631 	for (i = 0; i < 3; i++)
632 		outb(val >> (8 * i), base_offset);
633 
634 	/* Transfer Preset Register to Counter */
635 	outb(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, base_offset + 1);
636 
637 	/* Reset Byte Pointer */
638 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
639 
640 	/* Set Preset Register back to original value */
641 	val = priv->preset[count->id];
642 	for (i = 0; i < 3; i++)
643 		outb(val >> (8 * i), base_offset);
644 
645 	/* Reset Borrow, Carry, Compare, and Sign flags */
646 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
647 	/* Reset Error flag */
648 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
649 
650 	return 0;
651 }
652 
653 enum quad8_count_function {
654 	QUAD8_COUNT_FUNCTION_PULSE_DIRECTION = 0,
655 	QUAD8_COUNT_FUNCTION_QUADRATURE_X1,
656 	QUAD8_COUNT_FUNCTION_QUADRATURE_X2,
657 	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
658 };
659 
660 static enum counter_count_function quad8_count_functions_list[] = {
661 	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
662 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
663 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
664 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X4] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4
665 };
666 
667 static int quad8_function_get(struct counter_device *counter,
668 	struct counter_count *count, size_t *function)
669 {
670 	const struct quad8_iio *const priv = counter->priv;
671 	const int id = count->id;
672 	const unsigned int quadrature_mode = priv->quadrature_mode[id];
673 	const unsigned int scale = priv->quadrature_scale[id];
674 
675 	if (quadrature_mode)
676 		switch (scale) {
677 		case 0:
678 			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X1;
679 			break;
680 		case 1:
681 			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X2;
682 			break;
683 		case 2:
684 			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X4;
685 			break;
686 		}
687 	else
688 		*function = QUAD8_COUNT_FUNCTION_PULSE_DIRECTION;
689 
690 	return 0;
691 }
692 
693 static int quad8_function_set(struct counter_device *counter,
694 	struct counter_count *count, size_t function)
695 {
696 	struct quad8_iio *const priv = counter->priv;
697 	const int id = count->id;
698 	unsigned int *const quadrature_mode = priv->quadrature_mode + id;
699 	unsigned int *const scale = priv->quadrature_scale + id;
700 	unsigned int mode_cfg = priv->count_mode[id] << 1;
701 	unsigned int *const synchronous_mode = priv->synchronous_mode + id;
702 	const unsigned int idr_cfg = priv->index_polarity[id] << 1;
703 	const int base_offset = priv->base + 2 * id + 1;
704 
705 	if (function == QUAD8_COUNT_FUNCTION_PULSE_DIRECTION) {
706 		*quadrature_mode = 0;
707 
708 		/* Quadrature scaling only available in quadrature mode */
709 		*scale = 0;
710 
711 		/* Synchronous function not supported in non-quadrature mode */
712 		if (*synchronous_mode) {
713 			*synchronous_mode = 0;
714 			/* Disable synchronous function mode */
715 			outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
716 		}
717 	} else {
718 		*quadrature_mode = 1;
719 
720 		switch (function) {
721 		case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
722 			*scale = 0;
723 			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
724 			break;
725 		case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
726 			*scale = 1;
727 			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
728 			break;
729 		case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
730 			*scale = 2;
731 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
732 			break;
733 		}
734 	}
735 
736 	/* Load mode configuration to Counter Mode Register */
737 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
738 
739 	return 0;
740 }
741 
742 static void quad8_direction_get(struct counter_device *counter,
743 	struct counter_count *count, enum counter_count_direction *direction)
744 {
745 	const struct quad8_iio *const priv = counter->priv;
746 	unsigned int ud_flag;
747 	const unsigned int flag_addr = priv->base + 2 * count->id + 1;
748 
749 	/* U/D flag: nonzero = up, zero = down */
750 	ud_flag = inb(flag_addr) & QUAD8_FLAG_UD;
751 
752 	*direction = (ud_flag) ? COUNTER_COUNT_DIRECTION_FORWARD :
753 		COUNTER_COUNT_DIRECTION_BACKWARD;
754 }
755 
756 enum quad8_synapse_action {
757 	QUAD8_SYNAPSE_ACTION_NONE = 0,
758 	QUAD8_SYNAPSE_ACTION_RISING_EDGE,
759 	QUAD8_SYNAPSE_ACTION_FALLING_EDGE,
760 	QUAD8_SYNAPSE_ACTION_BOTH_EDGES
761 };
762 
763 static enum counter_synapse_action quad8_index_actions_list[] = {
764 	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
765 	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE
766 };
767 
768 static enum counter_synapse_action quad8_synapse_actions_list[] = {
769 	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
770 	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
771 	[QUAD8_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
772 	[QUAD8_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
773 };
774 
775 static int quad8_action_get(struct counter_device *counter,
776 	struct counter_count *count, struct counter_synapse *synapse,
777 	size_t *action)
778 {
779 	struct quad8_iio *const priv = counter->priv;
780 	int err;
781 	size_t function = 0;
782 	const size_t signal_a_id = count->synapses[0].signal->id;
783 	enum counter_count_direction direction;
784 
785 	/* Handle Index signals */
786 	if (synapse->signal->id >= 16) {
787 		if (priv->preset_enable[count->id])
788 			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
789 		else
790 			*action = QUAD8_SYNAPSE_ACTION_NONE;
791 
792 		return 0;
793 	}
794 
795 	err = quad8_function_get(counter, count, &function);
796 	if (err)
797 		return err;
798 
799 	/* Default action mode */
800 	*action = QUAD8_SYNAPSE_ACTION_NONE;
801 
802 	/* Determine action mode based on current count function mode */
803 	switch (function) {
804 	case QUAD8_COUNT_FUNCTION_PULSE_DIRECTION:
805 		if (synapse->signal->id == signal_a_id)
806 			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
807 		break;
808 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
809 		if (synapse->signal->id == signal_a_id) {
810 			quad8_direction_get(counter, count, &direction);
811 
812 			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
813 				*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
814 			else
815 				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
816 		}
817 		break;
818 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
819 		if (synapse->signal->id == signal_a_id)
820 			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
821 		break;
822 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
823 		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
824 		break;
825 	}
826 
827 	return 0;
828 }
829 
830 static const struct counter_ops quad8_ops = {
831 	.signal_read = quad8_signal_read,
832 	.count_read = quad8_count_read,
833 	.count_write = quad8_count_write,
834 	.function_get = quad8_function_get,
835 	.function_set = quad8_function_set,
836 	.action_get = quad8_action_get
837 };
838 
839 static int quad8_index_polarity_get(struct counter_device *counter,
840 	struct counter_signal *signal, size_t *index_polarity)
841 {
842 	const struct quad8_iio *const priv = counter->priv;
843 	const size_t channel_id = signal->id - 16;
844 
845 	*index_polarity = priv->index_polarity[channel_id];
846 
847 	return 0;
848 }
849 
850 static int quad8_index_polarity_set(struct counter_device *counter,
851 	struct counter_signal *signal, size_t index_polarity)
852 {
853 	struct quad8_iio *const priv = counter->priv;
854 	const size_t channel_id = signal->id - 16;
855 	const unsigned int idr_cfg = priv->synchronous_mode[channel_id] |
856 		index_polarity << 1;
857 	const int base_offset = priv->base + 2 * channel_id + 1;
858 
859 	priv->index_polarity[channel_id] = index_polarity;
860 
861 	/* Load Index Control configuration to Index Control Register */
862 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
863 
864 	return 0;
865 }
866 
867 static struct counter_signal_enum_ext quad8_index_pol_enum = {
868 	.items = quad8_index_polarity_modes,
869 	.num_items = ARRAY_SIZE(quad8_index_polarity_modes),
870 	.get = quad8_index_polarity_get,
871 	.set = quad8_index_polarity_set
872 };
873 
874 static int quad8_synchronous_mode_get(struct counter_device *counter,
875 	struct counter_signal *signal, size_t *synchronous_mode)
876 {
877 	const struct quad8_iio *const priv = counter->priv;
878 	const size_t channel_id = signal->id - 16;
879 
880 	*synchronous_mode = priv->synchronous_mode[channel_id];
881 
882 	return 0;
883 }
884 
885 static int quad8_synchronous_mode_set(struct counter_device *counter,
886 	struct counter_signal *signal, size_t synchronous_mode)
887 {
888 	struct quad8_iio *const priv = counter->priv;
889 	const size_t channel_id = signal->id - 16;
890 	const unsigned int idr_cfg = synchronous_mode |
891 		priv->index_polarity[channel_id] << 1;
892 	const int base_offset = priv->base + 2 * channel_id + 1;
893 
894 	/* Index function must be non-synchronous in non-quadrature mode */
895 	if (synchronous_mode && !priv->quadrature_mode[channel_id])
896 		return -EINVAL;
897 
898 	priv->synchronous_mode[channel_id] = synchronous_mode;
899 
900 	/* Load Index Control configuration to Index Control Register */
901 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
902 
903 	return 0;
904 }
905 
906 static struct counter_signal_enum_ext quad8_syn_mode_enum = {
907 	.items = quad8_synchronous_modes,
908 	.num_items = ARRAY_SIZE(quad8_synchronous_modes),
909 	.get = quad8_synchronous_mode_get,
910 	.set = quad8_synchronous_mode_set
911 };
912 
913 static ssize_t quad8_count_floor_read(struct counter_device *counter,
914 	struct counter_count *count, void *private, char *buf)
915 {
916 	/* Only a floor of 0 is supported */
917 	return sprintf(buf, "0\n");
918 }
919 
920 static int quad8_count_mode_get(struct counter_device *counter,
921 	struct counter_count *count, size_t *cnt_mode)
922 {
923 	const struct quad8_iio *const priv = counter->priv;
924 
925 	/* Map 104-QUAD-8 count mode to Generic Counter count mode */
926 	switch (priv->count_mode[count->id]) {
927 	case 0:
928 		*cnt_mode = COUNTER_COUNT_MODE_NORMAL;
929 		break;
930 	case 1:
931 		*cnt_mode = COUNTER_COUNT_MODE_RANGE_LIMIT;
932 		break;
933 	case 2:
934 		*cnt_mode = COUNTER_COUNT_MODE_NON_RECYCLE;
935 		break;
936 	case 3:
937 		*cnt_mode = COUNTER_COUNT_MODE_MODULO_N;
938 		break;
939 	}
940 
941 	return 0;
942 }
943 
944 static int quad8_count_mode_set(struct counter_device *counter,
945 	struct counter_count *count, size_t cnt_mode)
946 {
947 	struct quad8_iio *const priv = counter->priv;
948 	unsigned int mode_cfg;
949 	const int base_offset = priv->base + 2 * count->id + 1;
950 
951 	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
952 	switch (cnt_mode) {
953 	case COUNTER_COUNT_MODE_NORMAL:
954 		cnt_mode = 0;
955 		break;
956 	case COUNTER_COUNT_MODE_RANGE_LIMIT:
957 		cnt_mode = 1;
958 		break;
959 	case COUNTER_COUNT_MODE_NON_RECYCLE:
960 		cnt_mode = 2;
961 		break;
962 	case COUNTER_COUNT_MODE_MODULO_N:
963 		cnt_mode = 3;
964 		break;
965 	}
966 
967 	priv->count_mode[count->id] = cnt_mode;
968 
969 	/* Set count mode configuration value */
970 	mode_cfg = cnt_mode << 1;
971 
972 	/* Add quadrature mode configuration */
973 	if (priv->quadrature_mode[count->id])
974 		mode_cfg |= (priv->quadrature_scale[count->id] + 1) << 3;
975 
976 	/* Load mode configuration to Counter Mode Register */
977 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
978 
979 	return 0;
980 }
981 
982 static struct counter_count_enum_ext quad8_cnt_mode_enum = {
983 	.items = counter_count_mode_str,
984 	.num_items = ARRAY_SIZE(counter_count_mode_str),
985 	.get = quad8_count_mode_get,
986 	.set = quad8_count_mode_set
987 };
988 
989 static ssize_t quad8_count_direction_read(struct counter_device *counter,
990 	struct counter_count *count, void *priv, char *buf)
991 {
992 	enum counter_count_direction dir;
993 
994 	quad8_direction_get(counter, count, &dir);
995 
996 	return sprintf(buf, "%s\n", counter_count_direction_str[dir]);
997 }
998 
999 static ssize_t quad8_count_enable_read(struct counter_device *counter,
1000 	struct counter_count *count, void *private, char *buf)
1001 {
1002 	const struct quad8_iio *const priv = counter->priv;
1003 
1004 	return sprintf(buf, "%u\n", priv->ab_enable[count->id]);
1005 }
1006 
1007 static ssize_t quad8_count_enable_write(struct counter_device *counter,
1008 	struct counter_count *count, void *private, const char *buf, size_t len)
1009 {
1010 	struct quad8_iio *const priv = counter->priv;
1011 	const int base_offset = priv->base + 2 * count->id;
1012 	int err;
1013 	bool ab_enable;
1014 	unsigned int ior_cfg;
1015 
1016 	err = kstrtobool(buf, &ab_enable);
1017 	if (err)
1018 		return err;
1019 
1020 	priv->ab_enable[count->id] = ab_enable;
1021 
1022 	ior_cfg = ab_enable | priv->preset_enable[count->id] << 1;
1023 
1024 	/* Load I/O control configuration */
1025 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
1026 
1027 	return len;
1028 }
1029 
1030 static int quad8_error_noise_get(struct counter_device *counter,
1031 	struct counter_count *count, size_t *noise_error)
1032 {
1033 	const struct quad8_iio *const priv = counter->priv;
1034 	const int base_offset = priv->base + 2 * count->id + 1;
1035 
1036 	*noise_error = !!(inb(base_offset) & QUAD8_FLAG_E);
1037 
1038 	return 0;
1039 }
1040 
1041 static struct counter_count_enum_ext quad8_error_noise_enum = {
1042 	.items = quad8_noise_error_states,
1043 	.num_items = ARRAY_SIZE(quad8_noise_error_states),
1044 	.get = quad8_error_noise_get
1045 };
1046 
1047 static ssize_t quad8_count_preset_read(struct counter_device *counter,
1048 	struct counter_count *count, void *private, char *buf)
1049 {
1050 	const struct quad8_iio *const priv = counter->priv;
1051 
1052 	return sprintf(buf, "%u\n", priv->preset[count->id]);
1053 }
1054 
1055 static ssize_t quad8_count_preset_write(struct counter_device *counter,
1056 	struct counter_count *count, void *private, const char *buf, size_t len)
1057 {
1058 	struct quad8_iio *const priv = counter->priv;
1059 	const int base_offset = priv->base + 2 * count->id;
1060 	unsigned int preset;
1061 	int ret;
1062 	int i;
1063 
1064 	ret = kstrtouint(buf, 0, &preset);
1065 	if (ret)
1066 		return ret;
1067 
1068 	/* Only 24-bit values are supported */
1069 	if (preset > 0xFFFFFF)
1070 		return -EINVAL;
1071 
1072 	priv->preset[count->id] = preset;
1073 
1074 	/* Reset Byte Pointer */
1075 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
1076 
1077 	/* Set Preset Register */
1078 	for (i = 0; i < 3; i++)
1079 		outb(preset >> (8 * i), base_offset);
1080 
1081 	return len;
1082 }
1083 
1084 static ssize_t quad8_count_ceiling_read(struct counter_device *counter,
1085 	struct counter_count *count, void *private, char *buf)
1086 {
1087 	const struct quad8_iio *const priv = counter->priv;
1088 
1089 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
1090 	switch (priv->count_mode[count->id]) {
1091 	case 1:
1092 	case 3:
1093 		return quad8_count_preset_read(counter, count, private, buf);
1094 	}
1095 
1096 	/* By default 0x1FFFFFF (25 bits unsigned) is maximum count */
1097 	return sprintf(buf, "33554431\n");
1098 }
1099 
1100 static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
1101 	struct counter_count *count, void *private, const char *buf, size_t len)
1102 {
1103 	struct quad8_iio *const priv = counter->priv;
1104 
1105 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
1106 	switch (priv->count_mode[count->id]) {
1107 	case 1:
1108 	case 3:
1109 		return quad8_count_preset_write(counter, count, private, buf,
1110 						len);
1111 	}
1112 
1113 	return len;
1114 }
1115 
1116 static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,
1117 	struct counter_count *count, void *private, char *buf)
1118 {
1119 	const struct quad8_iio *const priv = counter->priv;
1120 
1121 	return sprintf(buf, "%u\n", !priv->preset_enable[count->id]);
1122 }
1123 
1124 static ssize_t quad8_count_preset_enable_write(struct counter_device *counter,
1125 	struct counter_count *count, void *private, const char *buf, size_t len)
1126 {
1127 	struct quad8_iio *const priv = counter->priv;
1128 	const int base_offset = priv->base + 2 * count->id + 1;
1129 	bool preset_enable;
1130 	int ret;
1131 	unsigned int ior_cfg;
1132 
1133 	ret = kstrtobool(buf, &preset_enable);
1134 	if (ret)
1135 		return ret;
1136 
1137 	/* Preset enable is active low in Input/Output Control register */
1138 	preset_enable = !preset_enable;
1139 
1140 	priv->preset_enable[count->id] = preset_enable;
1141 
1142 	ior_cfg = priv->ab_enable[count->id] | (unsigned int)preset_enable << 1;
1143 
1144 	/* Load I/O control configuration to Input / Output Control Register */
1145 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
1146 
1147 	return len;
1148 }
1149 
1150 static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter,
1151 					     struct counter_signal *signal,
1152 					     void *private, char *buf)
1153 {
1154 	const struct quad8_iio *const priv = counter->priv;
1155 	const size_t channel_id = signal->id / 2;
1156 	const bool disabled = !(priv->cable_fault_enable & BIT(channel_id));
1157 	unsigned int status;
1158 	unsigned int fault;
1159 
1160 	if (disabled)
1161 		return -EINVAL;
1162 
1163 	/* Logic 0 = cable fault */
1164 	status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
1165 
1166 	/* Mask respective channel and invert logic */
1167 	fault = !(status & BIT(channel_id));
1168 
1169 	return sprintf(buf, "%u\n", fault);
1170 }
1171 
1172 static ssize_t quad8_signal_cable_fault_enable_read(
1173 	struct counter_device *counter, struct counter_signal *signal,
1174 	void *private, char *buf)
1175 {
1176 	const struct quad8_iio *const priv = counter->priv;
1177 	const size_t channel_id = signal->id / 2;
1178 	const unsigned int enb = !!(priv->cable_fault_enable & BIT(channel_id));
1179 
1180 	return sprintf(buf, "%u\n", enb);
1181 }
1182 
1183 static ssize_t quad8_signal_cable_fault_enable_write(
1184 	struct counter_device *counter, struct counter_signal *signal,
1185 	void *private, const char *buf, size_t len)
1186 {
1187 	struct quad8_iio *const priv = counter->priv;
1188 	const size_t channel_id = signal->id / 2;
1189 	bool enable;
1190 	int ret;
1191 	unsigned int cable_fault_enable;
1192 
1193 	ret = kstrtobool(buf, &enable);
1194 	if (ret)
1195 		return ret;
1196 
1197 	if (enable)
1198 		priv->cable_fault_enable |= BIT(channel_id);
1199 	else
1200 		priv->cable_fault_enable &= ~BIT(channel_id);
1201 
1202 	/* Enable is active low in Differential Encoder Cable Status register */
1203 	cable_fault_enable = ~priv->cable_fault_enable;
1204 
1205 	outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
1206 
1207 	return len;
1208 }
1209 
1210 static ssize_t quad8_signal_fck_prescaler_read(struct counter_device *counter,
1211 	struct counter_signal *signal, void *private, char *buf)
1212 {
1213 	const struct quad8_iio *const priv = counter->priv;
1214 	const size_t channel_id = signal->id / 2;
1215 
1216 	return sprintf(buf, "%u\n", priv->fck_prescaler[channel_id]);
1217 }
1218 
1219 static ssize_t quad8_signal_fck_prescaler_write(struct counter_device *counter,
1220 	struct counter_signal *signal, void *private, const char *buf,
1221 	size_t len)
1222 {
1223 	struct quad8_iio *const priv = counter->priv;
1224 	const size_t channel_id = signal->id / 2;
1225 	const int base_offset = priv->base + 2 * channel_id;
1226 	u8 prescaler;
1227 	int ret;
1228 
1229 	ret = kstrtou8(buf, 0, &prescaler);
1230 	if (ret)
1231 		return ret;
1232 
1233 	priv->fck_prescaler[channel_id] = prescaler;
1234 
1235 	/* Reset Byte Pointer */
1236 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
1237 
1238 	/* Set filter clock factor */
1239 	outb(prescaler, base_offset);
1240 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
1241 	     base_offset + 1);
1242 
1243 	return len;
1244 }
1245 
1246 static const struct counter_signal_ext quad8_signal_ext[] = {
1247 	{
1248 		.name = "cable_fault",
1249 		.read = quad8_signal_cable_fault_read
1250 	},
1251 	{
1252 		.name = "cable_fault_enable",
1253 		.read = quad8_signal_cable_fault_enable_read,
1254 		.write = quad8_signal_cable_fault_enable_write
1255 	},
1256 	{
1257 		.name = "filter_clock_prescaler",
1258 		.read = quad8_signal_fck_prescaler_read,
1259 		.write = quad8_signal_fck_prescaler_write
1260 	}
1261 };
1262 
1263 static const struct counter_signal_ext quad8_index_ext[] = {
1264 	COUNTER_SIGNAL_ENUM("index_polarity", &quad8_index_pol_enum),
1265 	COUNTER_SIGNAL_ENUM_AVAILABLE("index_polarity",	&quad8_index_pol_enum),
1266 	COUNTER_SIGNAL_ENUM("synchronous_mode", &quad8_syn_mode_enum),
1267 	COUNTER_SIGNAL_ENUM_AVAILABLE("synchronous_mode", &quad8_syn_mode_enum)
1268 };
1269 
1270 #define QUAD8_QUAD_SIGNAL(_id, _name) {		\
1271 	.id = (_id),				\
1272 	.name = (_name),			\
1273 	.ext = quad8_signal_ext,		\
1274 	.num_ext = ARRAY_SIZE(quad8_signal_ext)	\
1275 }
1276 
1277 #define	QUAD8_INDEX_SIGNAL(_id, _name) {	\
1278 	.id = (_id),				\
1279 	.name = (_name),			\
1280 	.ext = quad8_index_ext,			\
1281 	.num_ext = ARRAY_SIZE(quad8_index_ext)	\
1282 }
1283 
1284 static struct counter_signal quad8_signals[] = {
1285 	QUAD8_QUAD_SIGNAL(0, "Channel 1 Quadrature A"),
1286 	QUAD8_QUAD_SIGNAL(1, "Channel 1 Quadrature B"),
1287 	QUAD8_QUAD_SIGNAL(2, "Channel 2 Quadrature A"),
1288 	QUAD8_QUAD_SIGNAL(3, "Channel 2 Quadrature B"),
1289 	QUAD8_QUAD_SIGNAL(4, "Channel 3 Quadrature A"),
1290 	QUAD8_QUAD_SIGNAL(5, "Channel 3 Quadrature B"),
1291 	QUAD8_QUAD_SIGNAL(6, "Channel 4 Quadrature A"),
1292 	QUAD8_QUAD_SIGNAL(7, "Channel 4 Quadrature B"),
1293 	QUAD8_QUAD_SIGNAL(8, "Channel 5 Quadrature A"),
1294 	QUAD8_QUAD_SIGNAL(9, "Channel 5 Quadrature B"),
1295 	QUAD8_QUAD_SIGNAL(10, "Channel 6 Quadrature A"),
1296 	QUAD8_QUAD_SIGNAL(11, "Channel 6 Quadrature B"),
1297 	QUAD8_QUAD_SIGNAL(12, "Channel 7 Quadrature A"),
1298 	QUAD8_QUAD_SIGNAL(13, "Channel 7 Quadrature B"),
1299 	QUAD8_QUAD_SIGNAL(14, "Channel 8 Quadrature A"),
1300 	QUAD8_QUAD_SIGNAL(15, "Channel 8 Quadrature B"),
1301 	QUAD8_INDEX_SIGNAL(16, "Channel 1 Index"),
1302 	QUAD8_INDEX_SIGNAL(17, "Channel 2 Index"),
1303 	QUAD8_INDEX_SIGNAL(18, "Channel 3 Index"),
1304 	QUAD8_INDEX_SIGNAL(19, "Channel 4 Index"),
1305 	QUAD8_INDEX_SIGNAL(20, "Channel 5 Index"),
1306 	QUAD8_INDEX_SIGNAL(21, "Channel 6 Index"),
1307 	QUAD8_INDEX_SIGNAL(22, "Channel 7 Index"),
1308 	QUAD8_INDEX_SIGNAL(23, "Channel 8 Index")
1309 };
1310 
1311 #define QUAD8_COUNT_SYNAPSES(_id) {					\
1312 	{								\
1313 		.actions_list = quad8_synapse_actions_list,		\
1314 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1315 		.signal = quad8_signals + 2 * (_id)			\
1316 	},								\
1317 	{								\
1318 		.actions_list = quad8_synapse_actions_list,		\
1319 		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
1320 		.signal = quad8_signals + 2 * (_id) + 1			\
1321 	},								\
1322 	{								\
1323 		.actions_list = quad8_index_actions_list,		\
1324 		.num_actions = ARRAY_SIZE(quad8_index_actions_list),	\
1325 		.signal = quad8_signals + 2 * (_id) + 16		\
1326 	}								\
1327 }
1328 
1329 static struct counter_synapse quad8_count_synapses[][3] = {
1330 	QUAD8_COUNT_SYNAPSES(0), QUAD8_COUNT_SYNAPSES(1),
1331 	QUAD8_COUNT_SYNAPSES(2), QUAD8_COUNT_SYNAPSES(3),
1332 	QUAD8_COUNT_SYNAPSES(4), QUAD8_COUNT_SYNAPSES(5),
1333 	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
1334 };
1335 
1336 static const struct counter_count_ext quad8_count_ext[] = {
1337 	{
1338 		.name = "ceiling",
1339 		.read = quad8_count_ceiling_read,
1340 		.write = quad8_count_ceiling_write
1341 	},
1342 	{
1343 		.name = "floor",
1344 		.read = quad8_count_floor_read
1345 	},
1346 	COUNTER_COUNT_ENUM("count_mode", &quad8_cnt_mode_enum),
1347 	COUNTER_COUNT_ENUM_AVAILABLE("count_mode", &quad8_cnt_mode_enum),
1348 	{
1349 		.name = "direction",
1350 		.read = quad8_count_direction_read
1351 	},
1352 	{
1353 		.name = "enable",
1354 		.read = quad8_count_enable_read,
1355 		.write = quad8_count_enable_write
1356 	},
1357 	COUNTER_COUNT_ENUM("error_noise", &quad8_error_noise_enum),
1358 	COUNTER_COUNT_ENUM_AVAILABLE("error_noise", &quad8_error_noise_enum),
1359 	{
1360 		.name = "preset",
1361 		.read = quad8_count_preset_read,
1362 		.write = quad8_count_preset_write
1363 	},
1364 	{
1365 		.name = "preset_enable",
1366 		.read = quad8_count_preset_enable_read,
1367 		.write = quad8_count_preset_enable_write
1368 	}
1369 };
1370 
1371 #define QUAD8_COUNT(_id, _cntname) {					\
1372 	.id = (_id),							\
1373 	.name = (_cntname),						\
1374 	.functions_list = quad8_count_functions_list,			\
1375 	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
1376 	.synapses = quad8_count_synapses[(_id)],			\
1377 	.num_synapses =	2,						\
1378 	.ext = quad8_count_ext,						\
1379 	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
1380 }
1381 
1382 static struct counter_count quad8_counts[] = {
1383 	QUAD8_COUNT(0, "Channel 1 Count"),
1384 	QUAD8_COUNT(1, "Channel 2 Count"),
1385 	QUAD8_COUNT(2, "Channel 3 Count"),
1386 	QUAD8_COUNT(3, "Channel 4 Count"),
1387 	QUAD8_COUNT(4, "Channel 5 Count"),
1388 	QUAD8_COUNT(5, "Channel 6 Count"),
1389 	QUAD8_COUNT(6, "Channel 7 Count"),
1390 	QUAD8_COUNT(7, "Channel 8 Count")
1391 };
1392 
1393 static int quad8_probe(struct device *dev, unsigned int id)
1394 {
1395 	struct iio_dev *indio_dev;
1396 	struct quad8_iio *quad8iio;
1397 	int i, j;
1398 	unsigned int base_offset;
1399 	int err;
1400 
1401 	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
1402 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
1403 			base[id], base[id] + QUAD8_EXTENT);
1404 		return -EBUSY;
1405 	}
1406 
1407 	/* Allocate IIO device; this also allocates driver data structure */
1408 	indio_dev = devm_iio_device_alloc(dev, sizeof(*quad8iio));
1409 	if (!indio_dev)
1410 		return -ENOMEM;
1411 
1412 	/* Initialize IIO device */
1413 	indio_dev->info = &quad8_info;
1414 	indio_dev->modes = INDIO_DIRECT_MODE;
1415 	indio_dev->num_channels = ARRAY_SIZE(quad8_channels);
1416 	indio_dev->channels = quad8_channels;
1417 	indio_dev->name = dev_name(dev);
1418 	indio_dev->dev.parent = dev;
1419 
1420 	/* Initialize Counter device and driver data */
1421 	quad8iio = iio_priv(indio_dev);
1422 	quad8iio->counter.name = dev_name(dev);
1423 	quad8iio->counter.parent = dev;
1424 	quad8iio->counter.ops = &quad8_ops;
1425 	quad8iio->counter.counts = quad8_counts;
1426 	quad8iio->counter.num_counts = ARRAY_SIZE(quad8_counts);
1427 	quad8iio->counter.signals = quad8_signals;
1428 	quad8iio->counter.num_signals = ARRAY_SIZE(quad8_signals);
1429 	quad8iio->counter.priv = quad8iio;
1430 	quad8iio->base = base[id];
1431 
1432 	/* Reset all counters and disable interrupt function */
1433 	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
1434 	/* Set initial configuration for all counters */
1435 	for (i = 0; i < QUAD8_NUM_COUNTERS; i++) {
1436 		base_offset = base[id] + 2 * i;
1437 		/* Reset Byte Pointer */
1438 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
1439 		/* Reset filter clock factor */
1440 		outb(0, base_offset);
1441 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
1442 		     base_offset + 1);
1443 		/* Reset Byte Pointer */
1444 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
1445 		/* Reset Preset Register */
1446 		for (j = 0; j < 3; j++)
1447 			outb(0x00, base_offset);
1448 		/* Reset Borrow, Carry, Compare, and Sign flags */
1449 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
1450 		/* Reset Error flag */
1451 		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
1452 		/* Binary encoding; Normal count; non-quadrature mode */
1453 		outb(QUAD8_CTR_CMR, base_offset + 1);
1454 		/* Disable A and B inputs; preset on index; FLG1 as Carry */
1455 		outb(QUAD8_CTR_IOR, base_offset + 1);
1456 		/* Disable index function; negative index polarity */
1457 		outb(QUAD8_CTR_IDR, base_offset + 1);
1458 	}
1459 	/* Disable Differential Encoder Cable Status for all channels */
1460 	outb(0xFF, base[id] + QUAD8_DIFF_ENCODER_CABLE_STATUS);
1461 	/* Enable all counters */
1462 	outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
1463 
1464 	/* Register IIO device */
1465 	err = devm_iio_device_register(dev, indio_dev);
1466 	if (err)
1467 		return err;
1468 
1469 	/* Register Counter device */
1470 	return devm_counter_register(dev, &quad8iio->counter);
1471 }
1472 
1473 static struct isa_driver quad8_driver = {
1474 	.probe = quad8_probe,
1475 	.driver = {
1476 		.name = "104-quad-8"
1477 	}
1478 };
1479 
1480 module_isa_driver(quad8_driver, num_quad8);
1481 
1482 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
1483 MODULE_DESCRIPTION("ACCES 104-QUAD-8 IIO driver");
1484 MODULE_LICENSE("GPL v2");
1485