summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpio-lynxpoint.c
blob: 13107772be4ffc4e1d12d471cf5df7a65a1ab639 (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
/*
 * GPIO controller driver for Intel Lynxpoint PCH chipset>
 * Copyright (c) 2012, Intel Corporation.
 *
 * Author: Mathias Nyman <mathias.nyman@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/io.h>

/* LynxPoint chipset has support for 94 gpio pins */

#define LP_NUM_GPIO	94

/* Bitmapped register offsets */
#define LP_ACPI_OWNED	0x00 /* Bitmap, set by bios, 0: pin reserved for ACPI */
#define LP_GC		0x7C /* set APIC IRQ to IRQ14 or IRQ15 for all pins */
#define LP_INT_STAT	0x80
#define LP_INT_ENABLE	0x90

/* Each pin has two 32 bit config registers, starting at 0x100 */
#define LP_CONFIG1	0x100
#define LP_CONFIG2	0x104

/* LP_CONFIG1 reg bits */
#define OUT_LVL_BIT	BIT(31)
#define IN_LVL_BIT	BIT(30)
#define TRIG_SEL_BIT	BIT(4) /* 0: Edge, 1: Level */
#define INT_INV_BIT	BIT(3) /* Invert interrupt triggering */
#define DIR_BIT		BIT(2) /* 0: Output, 1: Input */
#define USE_SEL_BIT	BIT(0) /* 0: Native, 1: GPIO */

/* LP_CONFIG2 reg bits */
#define GPINDIS_BIT	BIT(2) /* disable input sensing */
#define GPIWP_BIT	(BIT(0) | BIT(1)) /* weak pull options */

struct lp_gpio {
	struct gpio_chip	chip;
	struct platform_device	*pdev;
	spinlock_t		lock;
	unsigned long		reg_base;
};

/*
 * Lynxpoint gpios are controlled through both bitmapped registers and
 * per gpio specific registers. The bitmapped registers are in chunks of
 * 3 x 32bit registers to cover all 94 gpios
 *
 * per gpio specific registers consist of two 32bit registers per gpio
 * (LP_CONFIG1 and LP_CONFIG2), with 94 gpios there's a total of
 * 188 config registers.
 *
 * A simplified view of the register layout look like this:
 *
 * LP_ACPI_OWNED[31:0] gpio ownerships for gpios 0-31  (bitmapped registers)
 * LP_ACPI_OWNED[63:32] gpio ownerships for gpios 32-63
 * LP_ACPI_OWNED[94:64] gpio ownerships for gpios 63-94
 * ...
 * LP_INT_ENABLE[31:0] ...
 * LP_INT_ENABLE[63:31] ...
 * LP_INT_ENABLE[94:64] ...
 * LP0_CONFIG1 (gpio 0) config1 reg for gpio 0 (per gpio registers)
 * LP0_CONFIG2 (gpio 0) config2 reg for gpio 0
 * LP1_CONFIG1 (gpio 1) config1 reg for gpio 1
 * LP1_CONFIG2 (gpio 1) config2 reg for gpio 1
 * LP2_CONFIG1 (gpio 2) ...
 * LP2_CONFIG2 (gpio 2) ...
 * ...
 * LP94_CONFIG1 (gpio 94) ...
 * LP94_CONFIG2 (gpio 94) ...
 */

static unsigned long lp_gpio_reg(struct gpio_chip *chip, unsigned offset,
				 int reg)
{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	int reg_offset;

	if (reg == LP_CONFIG1 || reg == LP_CONFIG2)
		/* per gpio specific config registers */
		reg_offset = offset * 8;
	else
		/* bitmapped registers */
		reg_offset = (offset / 32) * 4;

	return lg->reg_base + reg + reg_offset;
}

static int lp_gpio_request(struct gpio_chip *chip, unsigned offset)
{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);
	unsigned long acpi_use = lp_gpio_reg(chip, offset, LP_ACPI_OWNED);

	pm_runtime_get(&lg->pdev->dev); /* should we put if failed */

	/* Fail if BIOS reserved pin for ACPI use */
	if (!(inl(acpi_use) & BIT(offset % 32))) {
		dev_err(&lg->pdev->dev, "gpio %d reserved for ACPI\n", offset);
		return -EBUSY;
	}
	/* Fail if pin is in alternate function mode (not GPIO mode) */
	if (!(inl(reg) & USE_SEL_BIT))
		return -ENODEV;

	/* enable input sensing */
	outl(inl(conf2) & ~GPINDIS_BIT, conf2);


	return 0;
}

static void lp_gpio_free(struct gpio_chip *chip, unsigned offset)
{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);

	/* disable input sensing */
	outl(inl(conf2) | GPINDIS_BIT, conf2);

	pm_runtime_put(&lg->pdev->dev);
}

static int lp_irq_type(struct irq_data *d, unsigned type)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct lp_gpio *lg = gpiochip_get_data(gc);
	u32 hwirq = irqd_to_hwirq(d);
	unsigned long flags;
	u32 value;
	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_CONFIG1);

	if (hwirq >= lg->chip.ngpio)
		return -EINVAL;

	spin_lock_irqsave(&lg->lock, flags);
	value = inl(reg);

	/* set both TRIG_SEL and INV bits to 0 for rising edge */
	if (type & IRQ_TYPE_EDGE_RISING)
		value &= ~(TRIG_SEL_BIT | INT_INV_BIT);

	/* TRIG_SEL bit 0, INV bit 1 for falling edge */
	if (type & IRQ_TYPE_EDGE_FALLING)
		value = (value | INT_INV_BIT) & ~TRIG_SEL_BIT;

	/* TRIG_SEL bit 1, INV bit 0 for level low */
	if (type & IRQ_TYPE_LEVEL_LOW)
		value = (value | TRIG_SEL_BIT) & ~INT_INV_BIT;

	/* TRIG_SEL bit 1, INV bit 1 for level high */
	if (type & IRQ_TYPE_LEVEL_HIGH)
		value |= TRIG_SEL_BIT | INT_INV_BIT;

	outl(value, reg);
	spin_unlock_irqrestore(&lg->lock, flags);

	return 0;
}

static int lp_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	return !!(inl(reg) & IN_LVL_BIT);
}

static void lp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	unsigned long flags;

	spin_lock_irqsave(&lg->lock, flags);

	if (value)
		outl(inl(reg) | OUT_LVL_BIT, reg);
	else
		outl(inl(reg) & ~OUT_LVL_BIT, reg);

	spin_unlock_irqrestore(&lg->lock, flags);
}

static int lp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	unsigned long flags;

	spin_lock_irqsave(&lg->lock, flags);
	outl(inl(reg) | DIR_BIT, reg);
	spin_unlock_irqrestore(&lg->lock, flags);

	return 0;
}

static int lp_gpio_direction_output(struct gpio_chip *chip,
				      unsigned offset, int value)
{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	unsigned long flags;

	lp_gpio_set(chip, offset, value);

	spin_lock_irqsave(&lg->lock, flags);
	outl(inl(reg) & ~DIR_BIT, reg);
	spin_unlock_irqrestore(&lg->lock, flags);

	return 0;
}

static void lp_gpio_irq_handler(struct irq_desc *desc)
{
	struct irq_data *data = irq_desc_get_irq_data(desc);
	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
	struct lp_gpio *lg = gpiochip_get_data(gc);
	struct irq_chip *chip = irq_data_get_irq_chip(data);
	u32 base, pin, mask;
	unsigned long reg, ena, pending;

	/* check from GPIO controller which pin triggered the interrupt */
	for (base = 0; base < lg->chip.ngpio; base += 32) {
		reg = lp_gpio_reg(&lg->chip, base, LP_INT_STAT);
		ena = lp_gpio_reg(&lg->chip, base, LP_INT_ENABLE);

		while ((pending = (inl(reg) & inl(ena)))) {
			unsigned irq;

			pin = __ffs(pending);
			mask = BIT(pin);
			/* Clear before handling so we don't lose an edge */
			outl(mask, reg);
			irq = irq_find_mapping(lg->chip.irqdomain, base + pin);
			generic_handle_irq(irq);
		}
	}
	chip->irq_eoi(data);
}

static void lp_irq_unmask(struct irq_data *d)
{
}

static void lp_irq_mask(struct irq_data *d)
{
}

static void lp_irq_enable(struct irq_data *d)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct lp_gpio *lg = gpiochip_get_data(gc);
	u32 hwirq = irqd_to_hwirq(d);
	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
	unsigned long flags;

	spin_lock_irqsave(&lg->lock, flags);
	outl(inl(reg) | BIT(hwirq % 32), reg);
	spin_unlock_irqrestore(&lg->lock, flags);
}

static void lp_irq_disable(struct irq_data *d)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct lp_gpio *lg = gpiochip_get_data(gc);
	u32 hwirq = irqd_to_hwirq(d);
	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
	unsigned long flags;

	spin_lock_irqsave(&lg->lock, flags);
	outl(inl(reg) & ~BIT(hwirq % 32), reg);
	spin_unlock_irqrestore(&lg->lock, flags);
}

static struct irq_chip lp_irqchip = {
	.name = "LP-GPIO",
	.irq_mask = lp_irq_mask,
	.irq_unmask = lp_irq_unmask,
	.irq_enable = lp_irq_enable,
	.irq_disable = lp_irq_disable,
	.irq_set_type = lp_irq_type,
	.flags = IRQCHIP_SKIP_SET_WAKE,
};

static void lp_gpio_irq_init_hw(struct lp_gpio *lg)
{
	unsigned long reg;
	unsigned base;

	for (base = 0; base < lg->chip.ngpio; base += 32) {
		/* disable gpio pin interrupts */
		reg = lp_gpio_reg(&lg->chip, base, LP_INT_ENABLE);
		outl(0, reg);
		/* Clear interrupt status register */
		reg = lp_gpio_reg(&lg->chip, base, LP_INT_STAT);
		outl(0xffffffff, reg);
	}
}

static int lp_gpio_probe(struct platform_device *pdev)
{
	struct lp_gpio *lg;
	struct gpio_chip *gc;
	struct resource *io_rc, *irq_rc;
	struct device *dev = &pdev->dev;
	unsigned long reg_len;
	int ret = -ENODEV;

	lg = devm_kzalloc(dev, sizeof(struct lp_gpio), GFP_KERNEL);
	if (!lg)
		return -ENOMEM;

	lg->pdev = pdev;
	platform_set_drvdata(pdev, lg);

	io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
	irq_rc = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

	if (!io_rc) {
		dev_err(dev, "missing IO resources\n");
		return -EINVAL;
	}

	lg->reg_base = io_rc->start;
	reg_len = resource_size(io_rc);

	if (!devm_request_region(dev, lg->reg_base, reg_len, "lp-gpio")) {
		dev_err(dev, "failed requesting IO region 0x%x\n",
			(unsigned int)lg->reg_base);
		return -EBUSY;
	}

	spin_lock_init(&lg->lock);

	gc = &lg->chip;
	gc->label = dev_name(dev);
	gc->owner = THIS_MODULE;
	gc->request = lp_gpio_request;
	gc->free = lp_gpio_free;
	gc->direction_input = lp_gpio_direction_input;
	gc->direction_output = lp_gpio_direction_output;
	gc->get = lp_gpio_get;
	gc->set = lp_gpio_set;
	gc->base = -1;
	gc->ngpio = LP_NUM_GPIO;
	gc->can_sleep = false;
	gc->parent = dev;

	ret = gpiochip_add_data(gc, lg);
	if (ret) {
		dev_err(dev, "failed adding lp-gpio chip\n");
		return ret;
	}

	/* set up interrupts  */
	if (irq_rc && irq_rc->start) {
		lp_gpio_irq_init_hw(lg);
		ret = gpiochip_irqchip_add(gc, &lp_irqchip, 0,
					   handle_simple_irq, IRQ_TYPE_NONE);
		if (ret) {
			dev_err(dev, "failed to add irqchip\n");
			gpiochip_remove(gc);
			return ret;
		}

		gpiochip_set_chained_irqchip(gc, &lp_irqchip,
					     (unsigned)irq_rc->start,
					     lp_gpio_irq_handler);
	}

	pm_runtime_enable(dev);

	return 0;
}

static int lp_gpio_runtime_suspend(struct device *dev)
{
	return 0;
}

static int lp_gpio_runtime_resume(struct device *dev)
{
	return 0;
}

static int lp_gpio_resume(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct lp_gpio *lg = platform_get_drvdata(pdev);
	unsigned long reg;
	int i;

	/* on some hardware suspend clears input sensing, re-enable it here */
	for (i = 0; i < lg->chip.ngpio; i++) {
		if (gpiochip_is_requested(&lg->chip, i) != NULL) {
			reg = lp_gpio_reg(&lg->chip, i, LP_CONFIG2);
			outl(inl(reg) & ~GPINDIS_BIT, reg);
		}
	}
	return 0;
}

static const struct dev_pm_ops lp_gpio_pm_ops = {
	.runtime_suspend = lp_gpio_runtime_suspend,
	.runtime_resume = lp_gpio_runtime_resume,
	.resume = lp_gpio_resume,
};

static const struct acpi_device_id lynxpoint_gpio_acpi_match[] = {
	{ "INT33C7", 0 },
	{ "INT3437", 0 },
	{ }
};
MODULE_DEVICE_TABLE(acpi, lynxpoint_gpio_acpi_match);

static int lp_gpio_remove(struct platform_device *pdev)
{
	struct lp_gpio *lg = platform_get_drvdata(pdev);
	pm_runtime_disable(&pdev->dev);
	gpiochip_remove(&lg->chip);
	return 0;
}

static struct platform_driver lp_gpio_driver = {
	.probe          = lp_gpio_probe,
	.remove         = lp_gpio_remove,
	.driver         = {
		.name   = "lp_gpio",
		.pm	= &lp_gpio_pm_ops,
		.acpi_match_table = ACPI_PTR(lynxpoint_gpio_acpi_match),
	},
};

static int __init lp_gpio_init(void)
{
	return platform_driver_register(&lp_gpio_driver);
}

static void __exit lp_gpio_exit(void)
{
	platform_driver_unregister(&lp_gpio_driver);
}

subsys_initcall(lp_gpio_init);
module_exit(lp_gpio_exit);

MODULE_AUTHOR("Mathias Nyman (Intel)");
MODULE_DESCRIPTION("GPIO interface for Intel Lynxpoint");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:lp_gpio");