summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpio-stmpe.c
blob: 994d542daf53fca19537e17dcbae4ff1b7cbe2cc (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) ST-Ericsson SA 2010
 *
 * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
 */

#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/mfd/stmpe.h>
#include <linux/seq_file.h>
#include <linux/bitops.h>

/*
 * These registers are modified under the irq bus lock and cached to avoid
 * unnecessary writes in bus_sync_unlock.
 */
enum { REG_RE, REG_FE, REG_IE };

enum { LSB, CSB, MSB };

#define CACHE_NR_REGS	3
/* No variant has more than 24 GPIOs */
#define CACHE_NR_BANKS	(24 / 8)

struct stmpe_gpio {
	struct gpio_chip chip;
	struct stmpe *stmpe;
	struct device *dev;
	struct mutex irq_lock;
	u32 norequest_mask;
	/* Caches of interrupt control registers for bus_lock */
	u8 regs[CACHE_NR_REGS][CACHE_NR_BANKS];
	u8 oldregs[CACHE_NR_REGS][CACHE_NR_BANKS];
};

static int stmpe_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	u8 reg = stmpe->regs[STMPE_IDX_GPMR_LSB + (offset / 8)];
	u8 mask = BIT(offset % 8);
	int ret;

	ret = stmpe_reg_read(stmpe, reg);
	if (ret < 0)
		return ret;

	return !!(ret & mask);
}

static void stmpe_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	int which = val ? STMPE_IDX_GPSR_LSB : STMPE_IDX_GPCR_LSB;
	u8 reg = stmpe->regs[which + (offset / 8)];
	u8 mask = BIT(offset % 8);

	/*
	 * Some variants have single register for gpio set/clear functionality.
	 * For them we need to write 0 to clear and 1 to set.
	 */
	if (stmpe->regs[STMPE_IDX_GPSR_LSB] == stmpe->regs[STMPE_IDX_GPCR_LSB])
		stmpe_set_bits(stmpe, reg, mask, val ? mask : 0);
	else
		stmpe_reg_write(stmpe, reg, mask);
}

static int stmpe_gpio_get_direction(struct gpio_chip *chip,
				    unsigned offset)
{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
	u8 mask = BIT(offset % 8);
	int ret;

	ret = stmpe_reg_read(stmpe, reg);
	if (ret < 0)
		return ret;

	return !(ret & mask);
}

static int stmpe_gpio_direction_output(struct gpio_chip *chip,
					 unsigned offset, int val)
{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB + (offset / 8)];
	u8 mask = BIT(offset % 8);

	stmpe_gpio_set(chip, offset, val);

	return stmpe_set_bits(stmpe, reg, mask, mask);
}

static int stmpe_gpio_direction_input(struct gpio_chip *chip,
					unsigned offset)
{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB + (offset / 8)];
	u8 mask = BIT(offset % 8);

	return stmpe_set_bits(stmpe, reg, mask, 0);
}

static int stmpe_gpio_request(struct gpio_chip *chip, unsigned offset)
{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;

	if (stmpe_gpio->norequest_mask & BIT(offset))
		return -EINVAL;

	return stmpe_set_altfunc(stmpe, BIT(offset), STMPE_BLOCK_GPIO);
}

static const struct gpio_chip template_chip = {
	.label			= "stmpe",
	.owner			= THIS_MODULE,
	.get_direction		= stmpe_gpio_get_direction,
	.direction_input	= stmpe_gpio_direction_input,
	.get			= stmpe_gpio_get,
	.direction_output	= stmpe_gpio_direction_output,
	.set			= stmpe_gpio_set,
	.request		= stmpe_gpio_request,
	.can_sleep		= true,
};

static int stmpe_gpio_irq_set_type(struct irq_data *d, unsigned int type)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	int offset = d->hwirq;
	int regoffset = offset / 8;
	int mask = BIT(offset % 8);

	if (type & IRQ_TYPE_LEVEL_LOW || type & IRQ_TYPE_LEVEL_HIGH)
		return -EINVAL;

	/* STMPE801 and STMPE 1600 don't have RE and FE registers */
	if (stmpe_gpio->stmpe->partnum == STMPE801 ||
	    stmpe_gpio->stmpe->partnum == STMPE1600)
		return 0;

	if (type & IRQ_TYPE_EDGE_RISING)
		stmpe_gpio->regs[REG_RE][regoffset] |= mask;
	else
		stmpe_gpio->regs[REG_RE][regoffset] &= ~mask;

	if (type & IRQ_TYPE_EDGE_FALLING)
		stmpe_gpio->regs[REG_FE][regoffset] |= mask;
	else
		stmpe_gpio->regs[REG_FE][regoffset] &= ~mask;

	return 0;
}

static void stmpe_gpio_irq_lock(struct irq_data *d)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);

	mutex_lock(&stmpe_gpio->irq_lock);
}

static void stmpe_gpio_irq_sync_unlock(struct irq_data *d)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
	static const u8 regmap[CACHE_NR_REGS][CACHE_NR_BANKS] = {
		[REG_RE][LSB] = STMPE_IDX_GPRER_LSB,
		[REG_RE][CSB] = STMPE_IDX_GPRER_CSB,
		[REG_RE][MSB] = STMPE_IDX_GPRER_MSB,
		[REG_FE][LSB] = STMPE_IDX_GPFER_LSB,
		[REG_FE][CSB] = STMPE_IDX_GPFER_CSB,
		[REG_FE][MSB] = STMPE_IDX_GPFER_MSB,
		[REG_IE][LSB] = STMPE_IDX_IEGPIOR_LSB,
		[REG_IE][CSB] = STMPE_IDX_IEGPIOR_CSB,
		[REG_IE][MSB] = STMPE_IDX_IEGPIOR_MSB,
	};
	int i, j;

	/*
	 * STMPE1600: to be able to get IRQ from pins,
	 * a read must be done on GPMR register, or a write in
	 * GPSR or GPCR registers
	 */
	if (stmpe->partnum == STMPE1600) {
		stmpe_reg_read(stmpe, stmpe->regs[STMPE_IDX_GPMR_LSB]);
		stmpe_reg_read(stmpe, stmpe->regs[STMPE_IDX_GPMR_CSB]);
	}

	for (i = 0; i < CACHE_NR_REGS; i++) {
		/* STMPE801 and STMPE1600 don't have RE and FE registers */
		if ((stmpe->partnum == STMPE801 ||
		     stmpe->partnum == STMPE1600) &&
		     (i != REG_IE))
			continue;

		for (j = 0; j < num_banks; j++) {
			u8 old = stmpe_gpio->oldregs[i][j];
			u8 new = stmpe_gpio->regs[i][j];

			if (new == old)
				continue;

			stmpe_gpio->oldregs[i][j] = new;
			stmpe_reg_write(stmpe, stmpe->regs[regmap[i][j]], new);
		}
	}

	mutex_unlock(&stmpe_gpio->irq_lock);
}

static void stmpe_gpio_irq_mask(struct irq_data *d)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	int offset = d->hwirq;
	int regoffset = offset / 8;
	int mask = BIT(offset % 8);

	stmpe_gpio->regs[REG_IE][regoffset] &= ~mask;
}

static void stmpe_gpio_irq_unmask(struct irq_data *d)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	int offset = d->hwirq;
	int regoffset = offset / 8;
	int mask = BIT(offset % 8);

	stmpe_gpio->regs[REG_IE][regoffset] |= mask;
}

static void stmpe_dbg_show_one(struct seq_file *s,
			       struct gpio_chip *gc,
			       unsigned offset, unsigned gpio)
{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	const char *label = gpiochip_is_requested(gc, offset);
	bool val = !!stmpe_gpio_get(gc, offset);
	u8 bank = offset / 8;
	u8 dir_reg = stmpe->regs[STMPE_IDX_GPDR_LSB + bank];
	u8 mask = BIT(offset % 8);
	int ret;
	u8 dir;

	ret = stmpe_reg_read(stmpe, dir_reg);
	if (ret < 0)
		return;
	dir = !!(ret & mask);

	if (dir) {
		seq_printf(s, " gpio-%-3d (%-20.20s) out %s",
			   gpio, label ?: "(none)",
			   val ? "hi" : "lo");
	} else {
		u8 edge_det_reg;
		u8 rise_reg;
		u8 fall_reg;
		u8 irqen_reg;

		static const char * const edge_det_values[] = {
			"edge-inactive",
			"edge-asserted",
			"not-supported"
		};
		static const char * const rise_values[] = {
			"no-rising-edge-detection",
			"rising-edge-detection",
			"not-supported"
		};
		static const char * const fall_values[] = {
			"no-falling-edge-detection",
			"falling-edge-detection",
			"not-supported"
		};
		#define NOT_SUPPORTED_IDX 2
		u8 edge_det = NOT_SUPPORTED_IDX;
		u8 rise = NOT_SUPPORTED_IDX;
		u8 fall = NOT_SUPPORTED_IDX;
		bool irqen;

		switch (stmpe->partnum) {
		case STMPE610:
		case STMPE811:
		case STMPE1601:
		case STMPE2401:
		case STMPE2403:
			edge_det_reg = stmpe->regs[STMPE_IDX_GPEDR_LSB + bank];
			ret = stmpe_reg_read(stmpe, edge_det_reg);
			if (ret < 0)
				return;
			edge_det = !!(ret & mask);
			/* fall through */
		case STMPE1801:
			rise_reg = stmpe->regs[STMPE_IDX_GPRER_LSB + bank];
			fall_reg = stmpe->regs[STMPE_IDX_GPFER_LSB + bank];

			ret = stmpe_reg_read(stmpe, rise_reg);
			if (ret < 0)
				return;
			rise = !!(ret & mask);
			ret = stmpe_reg_read(stmpe, fall_reg);
			if (ret < 0)
				return;
			fall = !!(ret & mask);
			/* fall through */
		case STMPE801:
		case STMPE1600:
			irqen_reg = stmpe->regs[STMPE_IDX_IEGPIOR_LSB + bank];
			break;

		default:
			return;
		}

		ret = stmpe_reg_read(stmpe, irqen_reg);
		if (ret < 0)
			return;
		irqen = !!(ret & mask);

		seq_printf(s, " gpio-%-3d (%-20.20s) in  %s %13s %13s %25s %25s",
			   gpio, label ?: "(none)",
			   val ? "hi" : "lo",
			   edge_det_values[edge_det],
			   irqen ? "IRQ-enabled" : "IRQ-disabled",
			   rise_values[rise],
			   fall_values[fall]);
	}
}

static void stmpe_dbg_show(struct seq_file *s, struct gpio_chip *gc)
{
	unsigned i;
	unsigned gpio = gc->base;

	for (i = 0; i < gc->ngpio; i++, gpio++) {
		stmpe_dbg_show_one(s, gc, i, gpio);
		seq_putc(s, '\n');
	}
}

static struct irq_chip stmpe_gpio_irq_chip = {
	.name			= "stmpe-gpio",
	.irq_bus_lock		= stmpe_gpio_irq_lock,
	.irq_bus_sync_unlock	= stmpe_gpio_irq_sync_unlock,
	.irq_mask		= stmpe_gpio_irq_mask,
	.irq_unmask		= stmpe_gpio_irq_unmask,
	.irq_set_type		= stmpe_gpio_irq_set_type,
};

#define MAX_GPIOS 24

static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
{
	struct stmpe_gpio *stmpe_gpio = dev;
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	u8 statmsbreg;
	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
	u8 status[DIV_ROUND_UP(MAX_GPIOS, 8)];
	int ret;
	int i;

	/*
	 * the stmpe_block_read() call below, imposes to set statmsbreg
	 * with the register located at the lowest address. As STMPE1600
	 * variant is the only one which respect registers address's order
	 * (LSB regs located at lowest address than MSB ones) whereas all
	 * the others have a registers layout with MSB located before the
	 * LSB regs.
	 */
	if (stmpe->partnum == STMPE1600)
		statmsbreg = stmpe->regs[STMPE_IDX_ISGPIOR_LSB];
	else
		statmsbreg = stmpe->regs[STMPE_IDX_ISGPIOR_MSB];

	ret = stmpe_block_read(stmpe, statmsbreg, num_banks, status);
	if (ret < 0)
		return IRQ_NONE;

	for (i = 0; i < num_banks; i++) {
		int bank = (stmpe_gpio->stmpe->partnum == STMPE1600) ? i :
			   num_banks - i - 1;
		unsigned int enabled = stmpe_gpio->regs[REG_IE][bank];
		unsigned int stat = status[i];

		stat &= enabled;
		if (!stat)
			continue;

		while (stat) {
			int bit = __ffs(stat);
			int line = bank * 8 + bit;
			int child_irq = irq_find_mapping(stmpe_gpio->chip.irq.domain,
							 line);

			handle_nested_irq(child_irq);
			stat &= ~BIT(bit);
		}

		/*
		 * interrupt status register write has no effect on
		 * 801/1801/1600, bits are cleared when read.
		 * Edge detect register is not present on 801/1600/1801
		 */
		if (stmpe->partnum != STMPE801 && stmpe->partnum != STMPE1600 &&
		    stmpe->partnum != STMPE1801) {
			stmpe_reg_write(stmpe, statmsbreg + i, status[i]);
			stmpe_reg_write(stmpe,
					stmpe->regs[STMPE_IDX_GPEDR_MSB] + i,
					status[i]);
		}
	}

	return IRQ_HANDLED;
}

static void stmpe_init_irq_valid_mask(struct gpio_chip *gc,
				      unsigned long *valid_mask,
				      unsigned int ngpios)
{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	int i;

	if (!stmpe_gpio->norequest_mask)
		return;

	/* Forbid unused lines to be mapped as IRQs */
	for (i = 0; i < sizeof(u32); i++) {
		if (stmpe_gpio->norequest_mask & BIT(i))
			clear_bit(i, valid_mask);
	}
}

static int stmpe_gpio_probe(struct platform_device *pdev)
{
	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
	struct device_node *np = pdev->dev.of_node;
	struct stmpe_gpio *stmpe_gpio;
	int ret, irq;

	if (stmpe->num_gpios > MAX_GPIOS) {
		dev_err(&pdev->dev, "Need to increase maximum GPIO number\n");
		return -EINVAL;
	}

	stmpe_gpio = kzalloc(sizeof(*stmpe_gpio), GFP_KERNEL);
	if (!stmpe_gpio)
		return -ENOMEM;

	mutex_init(&stmpe_gpio->irq_lock);

	stmpe_gpio->dev = &pdev->dev;
	stmpe_gpio->stmpe = stmpe;
	stmpe_gpio->chip = template_chip;
	stmpe_gpio->chip.ngpio = stmpe->num_gpios;
	stmpe_gpio->chip.parent = &pdev->dev;
	stmpe_gpio->chip.of_node = np;
	stmpe_gpio->chip.base = -1;
	/*
	 * REVISIT: this makes sure the valid mask gets allocated and
	 * filled in when adding the gpio_chip, but the rest of the
	 * gpio_irqchip is still filled in using the old method
	 * in gpiochip_irqchip_add_nested() so clean this up once we
	 * get the gpio_irqchip to initialize while adding the
	 * gpio_chip also for threaded irqchips.
	 */
	stmpe_gpio->chip.irq.init_valid_mask = stmpe_init_irq_valid_mask;

	if (IS_ENABLED(CONFIG_DEBUG_FS))
                stmpe_gpio->chip.dbg_show = stmpe_dbg_show;

	of_property_read_u32(np, "st,norequest-mask",
			&stmpe_gpio->norequest_mask);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		dev_info(&pdev->dev,
			"device configured in no-irq mode: "
			"irqs are not available\n");

	ret = stmpe_enable(stmpe, STMPE_BLOCK_GPIO);
	if (ret)
		goto out_free;

	ret = gpiochip_add_data(&stmpe_gpio->chip, stmpe_gpio);
	if (ret) {
		dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
		goto out_disable;
	}

	if (irq > 0) {
		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
				stmpe_gpio_irq, IRQF_ONESHOT,
				"stmpe-gpio", stmpe_gpio);
		if (ret) {
			dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
			goto out_disable;
		}
		ret =  gpiochip_irqchip_add_nested(&stmpe_gpio->chip,
						   &stmpe_gpio_irq_chip,
						   0,
						   handle_simple_irq,
						   IRQ_TYPE_NONE);
		if (ret) {
			dev_err(&pdev->dev,
				"could not connect irqchip to gpiochip\n");
			goto out_disable;
		}

		gpiochip_set_nested_irqchip(&stmpe_gpio->chip,
					    &stmpe_gpio_irq_chip,
					    irq);
	}

	platform_set_drvdata(pdev, stmpe_gpio);

	return 0;

out_disable:
	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
	gpiochip_remove(&stmpe_gpio->chip);
out_free:
	kfree(stmpe_gpio);
	return ret;
}

static struct platform_driver stmpe_gpio_driver = {
	.driver = {
		.suppress_bind_attrs	= true,
		.name			= "stmpe-gpio",
	},
	.probe		= stmpe_gpio_probe,
};

static int __init stmpe_gpio_init(void)
{
	return platform_driver_register(&stmpe_gpio_driver);
}
subsys_initcall(stmpe_gpio_init);