summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpio-adnp.c
blob: 416b2200d4f1b8f7aa385153c9ba50c6f870a54d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
/*
 * Copyright (C) 2011-2012 Avionic Design GmbH
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of_irq.h>
#include <linux/seq_file.h>
#include <linux/slab.h>

#define GPIO_DDR(gpio) (0x00 << (gpio)->reg_shift)
#define GPIO_PLR(gpio) (0x01 << (gpio)->reg_shift)
#define GPIO_IER(gpio) (0x02 << (gpio)->reg_shift)
#define GPIO_ISR(gpio) (0x03 << (gpio)->reg_shift)
#define GPIO_PTR(gpio) (0x04 << (gpio)->reg_shift)

struct adnp {
	struct i2c_client *client;
	struct gpio_chip gpio;
	unsigned int reg_shift;

	struct mutex i2c_lock;

	struct irq_domain *domain;
	struct mutex irq_lock;

	u8 *irq_enable;
	u8 *irq_level;
	u8 *irq_rise;
	u8 *irq_fall;
	u8 *irq_high;
	u8 *irq_low;
};

static inline struct adnp *to_adnp(struct gpio_chip *chip)
{
	return container_of(chip, struct adnp, gpio);
}

static int adnp_read(struct adnp *adnp, unsigned offset, uint8_t *value)
{
	int err;

	err = i2c_smbus_read_byte_data(adnp->client, offset);
	if (err < 0) {
		dev_err(adnp->gpio.dev, "%s failed: %d\n",
			"i2c_smbus_read_byte_data()", err);
		return err;
	}

	*value = err;
	return 0;
}

static int adnp_write(struct adnp *adnp, unsigned offset, uint8_t value)
{
	int err;

	err = i2c_smbus_write_byte_data(adnp->client, offset, value);
	if (err < 0) {
		dev_err(adnp->gpio.dev, "%s failed: %d\n",
			"i2c_smbus_write_byte_data()", err);
		return err;
	}

	return 0;
}

static int adnp_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct adnp *adnp = to_adnp(chip);
	unsigned int reg = offset >> adnp->reg_shift;
	unsigned int pos = offset & 7;
	u8 value;
	int err;

	err = adnp_read(adnp, GPIO_PLR(adnp) + reg, &value);
	if (err < 0)
		return err;

	return (value & BIT(pos)) ? 1 : 0;
}

static void __adnp_gpio_set(struct adnp *adnp, unsigned offset, int value)
{
	unsigned int reg = offset >> adnp->reg_shift;
	unsigned int pos = offset & 7;
	int err;
	u8 val;

	err = adnp_read(adnp, GPIO_PLR(adnp) + reg, &val);
	if (err < 0)
		return;

	if (value)
		val |= BIT(pos);
	else
		val &= ~BIT(pos);

	adnp_write(adnp, GPIO_PLR(adnp) + reg, val);
}

static void adnp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
	struct adnp *adnp = to_adnp(chip);

	mutex_lock(&adnp->i2c_lock);
	__adnp_gpio_set(adnp, offset, value);
	mutex_unlock(&adnp->i2c_lock);
}

static int adnp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
	struct adnp *adnp = to_adnp(chip);
	unsigned int reg = offset >> adnp->reg_shift;
	unsigned int pos = offset & 7;
	u8 value;
	int err;

	mutex_lock(&adnp->i2c_lock);

	err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &value);
	if (err < 0)
		goto out;

	value &= ~BIT(pos);

	err = adnp_write(adnp, GPIO_DDR(adnp) + reg, value);
	if (err < 0)
		goto out;

	err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &value);
	if (err < 0)
		goto out;

	if (err & BIT(pos))
		err = -EACCES;

	err = 0;

out:
	mutex_unlock(&adnp->i2c_lock);
	return err;
}

static int adnp_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
				      int value)
{
	struct adnp *adnp = to_adnp(chip);
	unsigned int reg = offset >> adnp->reg_shift;
	unsigned int pos = offset & 7;
	int err;
	u8 val;

	mutex_lock(&adnp->i2c_lock);

	err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &val);
	if (err < 0)
		goto out;

	val |= BIT(pos);

	err = adnp_write(adnp, GPIO_DDR(adnp) + reg, val);
	if (err < 0)
		goto out;

	err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &val);
	if (err < 0)
		goto out;

	if (!(val & BIT(pos))) {
		err = -EPERM;
		goto out;
	}

	__adnp_gpio_set(adnp, offset, value);
	err = 0;

out:
	mutex_unlock(&adnp->i2c_lock);
	return err;
}

static void adnp_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
	struct adnp *adnp = to_adnp(chip);
	unsigned int num_regs = 1 << adnp->reg_shift, i, j;
	int err;

	for (i = 0; i < num_regs; i++) {
		u8 ddr, plr, ier, isr;

		mutex_lock(&adnp->i2c_lock);

		err = adnp_read(adnp, GPIO_DDR(adnp) + i, &ddr);
		if (err < 0) {
			mutex_unlock(&adnp->i2c_lock);
			return;
		}

		err = adnp_read(adnp, GPIO_PLR(adnp) + i, &plr);
		if (err < 0) {
			mutex_unlock(&adnp->i2c_lock);
			return;
		}

		err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
		if (err < 0) {
			mutex_unlock(&adnp->i2c_lock);
			return;
		}

		err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
		if (err < 0) {
			mutex_unlock(&adnp->i2c_lock);
			return;
		}

		mutex_unlock(&adnp->i2c_lock);

		for (j = 0; j < 8; j++) {
			unsigned int bit = (i << adnp->reg_shift) + j;
			const char *direction = "input ";
			const char *level = "low ";
			const char *interrupt = "disabled";
			const char *pending = "";

			if (ddr & BIT(j))
				direction = "output";

			if (plr & BIT(j))
				level = "high";

			if (ier & BIT(j))
				interrupt = "enabled ";

			if (isr & BIT(j))
				pending = "pending";

			seq_printf(s, "%2u: %s %s IRQ %s %s\n", bit,
				   direction, level, interrupt, pending);
		}
	}
}

static int adnp_gpio_setup(struct adnp *adnp, unsigned int num_gpios)
{
	struct gpio_chip *chip = &adnp->gpio;

	adnp->reg_shift = get_count_order(num_gpios) - 3;

	chip->direction_input = adnp_gpio_direction_input;
	chip->direction_output = adnp_gpio_direction_output;
	chip->get = adnp_gpio_get;
	chip->set = adnp_gpio_set;
	chip->can_sleep = true;

	if (IS_ENABLED(CONFIG_DEBUG_FS))
		chip->dbg_show = adnp_gpio_dbg_show;

	chip->base = -1;
	chip->ngpio = num_gpios;
	chip->label = adnp->client->name;
	chip->dev = &adnp->client->dev;
	chip->of_node = chip->dev->of_node;
	chip->owner = THIS_MODULE;

	return 0;
}

static irqreturn_t adnp_irq(int irq, void *data)
{
	struct adnp *adnp = data;
	unsigned int num_regs, i;

	num_regs = 1 << adnp->reg_shift;

	for (i = 0; i < num_regs; i++) {
		unsigned int base = i << adnp->reg_shift, bit;
		u8 changed, level, isr, ier;
		unsigned long pending;
		int err;

		mutex_lock(&adnp->i2c_lock);

		err = adnp_read(adnp, GPIO_PLR(adnp) + i, &level);
		if (err < 0) {
			mutex_unlock(&adnp->i2c_lock);
			continue;
		}

		err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
		if (err < 0) {
			mutex_unlock(&adnp->i2c_lock);
			continue;
		}

		err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
		if (err < 0) {
			mutex_unlock(&adnp->i2c_lock);
			continue;
		}

		mutex_unlock(&adnp->i2c_lock);

		/* determine pins that changed levels */
		changed = level ^ adnp->irq_level[i];

		/* compute edge-triggered interrupts */
		pending = changed & ((adnp->irq_fall[i] & ~level) |
				     (adnp->irq_rise[i] & level));

		/* add in level-triggered interrupts */
		pending |= (adnp->irq_high[i] & level) |
			   (adnp->irq_low[i] & ~level);

		/* mask out non-pending and disabled interrupts */
		pending &= isr & ier;

		for_each_set_bit(bit, &pending, 8) {
			unsigned int child_irq;
			child_irq = irq_find_mapping(adnp->domain, base + bit);
			handle_nested_irq(child_irq);
		}
	}

	return IRQ_HANDLED;
}

static int adnp_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
{
	struct adnp *adnp = to_adnp(chip);
	return irq_create_mapping(adnp->domain, offset);
}

static void adnp_irq_mask(struct irq_data *data)
{
	struct adnp *adnp = irq_data_get_irq_chip_data(data);
	unsigned int reg = data->hwirq >> adnp->reg_shift;
	unsigned int pos = data->hwirq & 7;

	adnp->irq_enable[reg] &= ~BIT(pos);
}

static void adnp_irq_unmask(struct irq_data *data)
{
	struct adnp *adnp = irq_data_get_irq_chip_data(data);
	unsigned int reg = data->hwirq >> adnp->reg_shift;
	unsigned int pos = data->hwirq & 7;

	adnp->irq_enable[reg] |= BIT(pos);
}

static int adnp_irq_set_type(struct irq_data *data, unsigned int type)
{
	struct adnp *adnp = irq_data_get_irq_chip_data(data);
	unsigned int reg = data->hwirq >> adnp->reg_shift;
	unsigned int pos = data->hwirq & 7;

	if (type & IRQ_TYPE_EDGE_RISING)
		adnp->irq_rise[reg] |= BIT(pos);
	else
		adnp->irq_rise[reg] &= ~BIT(pos);

	if (type & IRQ_TYPE_EDGE_FALLING)
		adnp->irq_fall[reg] |= BIT(pos);
	else
		adnp->irq_fall[reg] &= ~BIT(pos);

	if (type & IRQ_TYPE_LEVEL_HIGH)
		adnp->irq_high[reg] |= BIT(pos);
	else
		adnp->irq_high[reg] &= ~BIT(pos);

	if (type & IRQ_TYPE_LEVEL_LOW)
		adnp->irq_low[reg] |= BIT(pos);
	else
		adnp->irq_low[reg] &= ~BIT(pos);

	return 0;
}

static void adnp_irq_bus_lock(struct irq_data *data)
{
	struct adnp *adnp = irq_data_get_irq_chip_data(data);

	mutex_lock(&adnp->irq_lock);
}

static void adnp_irq_bus_unlock(struct irq_data *data)
{
	struct adnp *adnp = irq_data_get_irq_chip_data(data);
	unsigned int num_regs = 1 << adnp->reg_shift, i;

	mutex_lock(&adnp->i2c_lock);

	for (i = 0; i < num_regs; i++)
		adnp_write(adnp, GPIO_IER(adnp) + i, adnp->irq_enable[i]);

	mutex_unlock(&adnp->i2c_lock);
	mutex_unlock(&adnp->irq_lock);
}

static int adnp_irq_reqres(struct irq_data *data)
{
	struct adnp *adnp = irq_data_get_irq_chip_data(data);

	if (gpio_lock_as_irq(&adnp->gpio, data->hwirq)) {
		dev_err(adnp->gpio.dev,
			"unable to lock HW IRQ %lu for IRQ\n",
			data->hwirq);
		return -EINVAL;
	}
	return 0;
}

static void adnp_irq_relres(struct irq_data *data)
{
	struct adnp *adnp = irq_data_get_irq_chip_data(data);

	gpio_unlock_as_irq(&adnp->gpio, data->hwirq);
}

static struct irq_chip adnp_irq_chip = {
	.name = "gpio-adnp",
	.irq_mask = adnp_irq_mask,
	.irq_unmask = adnp_irq_unmask,
	.irq_set_type = adnp_irq_set_type,
	.irq_bus_lock = adnp_irq_bus_lock,
	.irq_bus_sync_unlock = adnp_irq_bus_unlock,
	.irq_request_resources = adnp_irq_reqres,
	.irq_release_resources = adnp_irq_relres,
};

static int adnp_irq_map(struct irq_domain *domain, unsigned int irq,
			irq_hw_number_t hwirq)
{
	irq_set_chip_data(irq, domain->host_data);
	irq_set_chip(irq, &adnp_irq_chip);
	irq_set_nested_thread(irq, true);

#ifdef CONFIG_ARM
	set_irq_flags(irq, IRQF_VALID);
#else
	irq_set_noprobe(irq);
#endif

	return 0;
}

static const struct irq_domain_ops adnp_irq_domain_ops = {
	.map = adnp_irq_map,
	.xlate = irq_domain_xlate_twocell,
};

static int adnp_irq_setup(struct adnp *adnp)
{
	unsigned int num_regs = 1 << adnp->reg_shift, i;
	struct gpio_chip *chip = &adnp->gpio;
	int err;

	mutex_init(&adnp->irq_lock);

	/*
	 * Allocate memory to keep track of the current level and trigger
	 * modes of the interrupts. To avoid multiple allocations, a single
	 * large buffer is allocated and pointers are setup to point at the
	 * corresponding offsets. For consistency, the layout of the buffer
	 * is chosen to match the register layout of the hardware in that
	 * each segment contains the corresponding bits for all interrupts.
	 */
	adnp->irq_enable = devm_kzalloc(chip->dev, num_regs * 6, GFP_KERNEL);
	if (!adnp->irq_enable)
		return -ENOMEM;

	adnp->irq_level = adnp->irq_enable + (num_regs * 1);
	adnp->irq_rise = adnp->irq_enable + (num_regs * 2);
	adnp->irq_fall = adnp->irq_enable + (num_regs * 3);
	adnp->irq_high = adnp->irq_enable + (num_regs * 4);
	adnp->irq_low = adnp->irq_enable + (num_regs * 5);

	for (i = 0; i < num_regs; i++) {
		/*
		 * Read the initial level of all pins to allow the emulation
		 * of edge triggered interrupts.
		 */
		err = adnp_read(adnp, GPIO_PLR(adnp) + i, &adnp->irq_level[i]);
		if (err < 0)
			return err;

		/* disable all interrupts */
		err = adnp_write(adnp, GPIO_IER(adnp) + i, 0);
		if (err < 0)
			return err;

		adnp->irq_enable[i] = 0x00;
	}

	adnp->domain = irq_domain_add_linear(chip->of_node, chip->ngpio,
					     &adnp_irq_domain_ops, adnp);

	err = request_threaded_irq(adnp->client->irq, NULL, adnp_irq,
				   IRQF_TRIGGER_RISING | IRQF_ONESHOT,
				   dev_name(chip->dev), adnp);
	if (err != 0) {
		dev_err(chip->dev, "can't request IRQ#%d: %d\n",
			adnp->client->irq, err);
		return err;
	}

	chip->to_irq = adnp_gpio_to_irq;
	return 0;
}

static void adnp_irq_teardown(struct adnp *adnp)
{
	unsigned int irq, i;

	free_irq(adnp->client->irq, adnp);

	for (i = 0; i < adnp->gpio.ngpio; i++) {
		irq = irq_find_mapping(adnp->domain, i);
		if (irq > 0)
			irq_dispose_mapping(irq);
	}

	irq_domain_remove(adnp->domain);
}

static int adnp_i2c_probe(struct i2c_client *client,
				    const struct i2c_device_id *id)
{
	struct device_node *np = client->dev.of_node;
	struct adnp *adnp;
	u32 num_gpios;
	int err;

	err = of_property_read_u32(np, "nr-gpios", &num_gpios);
	if (err < 0)
		return err;

	client->irq = irq_of_parse_and_map(np, 0);
	if (!client->irq)
		return -EPROBE_DEFER;

	adnp = devm_kzalloc(&client->dev, sizeof(*adnp), GFP_KERNEL);
	if (!adnp)
		return -ENOMEM;

	mutex_init(&adnp->i2c_lock);
	adnp->client = client;

	err = adnp_gpio_setup(adnp, num_gpios);
	if (err < 0)
		return err;

	if (of_find_property(np, "interrupt-controller", NULL)) {
		err = adnp_irq_setup(adnp);
		if (err < 0)
			goto teardown;
	}

	err = gpiochip_add(&adnp->gpio);
	if (err < 0)
		goto teardown;

	i2c_set_clientdata(client, adnp);
	return 0;

teardown:
	if (of_find_property(np, "interrupt-controller", NULL))
		adnp_irq_teardown(adnp);

	return err;
}

static int adnp_i2c_remove(struct i2c_client *client)
{
	struct adnp *adnp = i2c_get_clientdata(client);
	struct device_node *np = client->dev.of_node;

	gpiochip_remove(&adnp->gpio);
	if (of_find_property(np, "interrupt-controller", NULL))
		adnp_irq_teardown(adnp);

	return 0;
}

static const struct i2c_device_id adnp_i2c_id[] = {
	{ "gpio-adnp" },
	{ },
};
MODULE_DEVICE_TABLE(i2c, adnp_i2c_id);

static const struct of_device_id adnp_of_match[] = {
	{ .compatible = "ad,gpio-adnp", },
	{ },
};
MODULE_DEVICE_TABLE(of, adnp_of_match);

static struct i2c_driver adnp_i2c_driver = {
	.driver = {
		.name = "gpio-adnp",
		.owner = THIS_MODULE,
		.of_match_table = adnp_of_match,
	},
	.probe = adnp_i2c_probe,
	.remove = adnp_i2c_remove,
	.id_table = adnp_i2c_id,
};
module_i2c_driver(adnp_i2c_driver);

MODULE_DESCRIPTION("Avionic Design N-bit GPIO expander");
MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
MODULE_LICENSE("GPL");