summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpio-htc-egpio.c
blob: 271356effb2e0ed7b84f52dabcfca812f10df9f9 (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
/*
 * Support for the GPIO/IRQ expander chips present on several HTC phones.
 * These are implemented in CPLD chips present on the board.
 *
 * Copyright (c) 2007 Kevin O'Connor <kevin@koconnor.net>
 * Copyright (c) 2007 Philipp Zabel <philipp.zabel@gmail.com>
 *
 * This file may be distributed under the terms of the GNU GPL license.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/platform_data/gpio-htc-egpio.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/init.h>

struct egpio_chip {
	int              reg_start;
	int              cached_values;
	unsigned long    is_out;
	struct device    *dev;
	struct gpio_chip chip;
};

struct egpio_info {
	spinlock_t        lock;

	/* iomem info */
	void __iomem      *base_addr;
	int               bus_shift;	/* byte shift */
	int               reg_shift;	/* bit shift */
	int               reg_mask;

	/* irq info */
	int               ack_register;
	int               ack_write;
	u16               irqs_enabled;
	uint              irq_start;
	int               nirqs;
	uint              chained_irq;

	/* egpio info */
	struct egpio_chip *chip;
	int               nchips;
};

static inline void egpio_writew(u16 value, struct egpio_info *ei, int reg)
{
	writew(value, ei->base_addr + (reg << ei->bus_shift));
}

static inline u16 egpio_readw(struct egpio_info *ei, int reg)
{
	return readw(ei->base_addr + (reg << ei->bus_shift));
}

/*
 * IRQs
 */

static inline void ack_irqs(struct egpio_info *ei)
{
	egpio_writew(ei->ack_write, ei, ei->ack_register);
	pr_debug("EGPIO ack - write %x to base+%x\n",
			ei->ack_write, ei->ack_register << ei->bus_shift);
}

static void egpio_ack(struct irq_data *data)
{
}

/* There does not appear to be a way to proactively mask interrupts
 * on the egpio chip itself.  So, we simply ignore interrupts that
 * aren't desired. */
static void egpio_mask(struct irq_data *data)
{
	struct egpio_info *ei = irq_data_get_irq_chip_data(data);
	ei->irqs_enabled &= ~(1 << (data->irq - ei->irq_start));
	pr_debug("EGPIO mask %d %04x\n", data->irq, ei->irqs_enabled);
}

static void egpio_unmask(struct irq_data *data)
{
	struct egpio_info *ei = irq_data_get_irq_chip_data(data);
	ei->irqs_enabled |= 1 << (data->irq - ei->irq_start);
	pr_debug("EGPIO unmask %d %04x\n", data->irq, ei->irqs_enabled);
}

static struct irq_chip egpio_muxed_chip = {
	.name		= "htc-egpio",
	.irq_ack	= egpio_ack,
	.irq_mask	= egpio_mask,
	.irq_unmask	= egpio_unmask,
};

static void egpio_handler(struct irq_desc *desc)
{
	struct egpio_info *ei = irq_desc_get_handler_data(desc);
	int irqpin;

	/* Read current pins. */
	unsigned long readval = egpio_readw(ei, ei->ack_register);
	pr_debug("IRQ reg: %x\n", (unsigned int)readval);
	/* Ack/unmask interrupts. */
	ack_irqs(ei);
	/* Process all set pins. */
	readval &= ei->irqs_enabled;
	for_each_set_bit(irqpin, &readval, ei->nirqs) {
		/* Run irq handler */
		pr_debug("got IRQ %d\n", irqpin);
		generic_handle_irq(ei->irq_start + irqpin);
	}
}

int htc_egpio_get_wakeup_irq(struct device *dev)
{
	struct egpio_info *ei = dev_get_drvdata(dev);

	/* Read current pins. */
	u16 readval = egpio_readw(ei, ei->ack_register);
	/* Ack/unmask interrupts. */
	ack_irqs(ei);
	/* Return first set pin. */
	readval &= ei->irqs_enabled;
	return ei->irq_start + ffs(readval) - 1;
}
EXPORT_SYMBOL(htc_egpio_get_wakeup_irq);

static inline int egpio_pos(struct egpio_info *ei, int bit)
{
	return bit >> ei->reg_shift;
}

static inline int egpio_bit(struct egpio_info *ei, int bit)
{
	return 1 << (bit & ((1 << ei->reg_shift)-1));
}

/*
 * Input pins
 */

static int egpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct egpio_chip *egpio;
	struct egpio_info *ei;
	unsigned           bit;
	int                reg;
	int                value;

	pr_debug("egpio_get_value(%d)\n", chip->base + offset);

	egpio = gpiochip_get_data(chip);
	ei    = dev_get_drvdata(egpio->dev);
	bit   = egpio_bit(ei, offset);
	reg   = egpio->reg_start + egpio_pos(ei, offset);

	if (test_bit(offset, &egpio->is_out)) {
		return !!(egpio->cached_values & (1 << offset));
	} else {
		value = egpio_readw(ei, reg);
		pr_debug("readw(%p + %x) = %x\n",
			 ei->base_addr, reg << ei->bus_shift, value);
		return !!(value & bit);
	}
}

static int egpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
	struct egpio_chip *egpio;

	egpio = gpiochip_get_data(chip);
	return test_bit(offset, &egpio->is_out) ? -EINVAL : 0;
}


/*
 * Output pins
 */

static void egpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
	unsigned long     flag;
	struct egpio_chip *egpio;
	struct egpio_info *ei;
	unsigned          bit;
	int               pos;
	int               reg;
	int               shift;

	pr_debug("egpio_set(%s, %d(%d), %d)\n",
			chip->label, offset, offset+chip->base, value);

	egpio = gpiochip_get_data(chip);
	ei    = dev_get_drvdata(egpio->dev);
	bit   = egpio_bit(ei, offset);
	pos   = egpio_pos(ei, offset);
	reg   = egpio->reg_start + pos;
	shift = pos << ei->reg_shift;

	pr_debug("egpio %s: reg %d = 0x%04x\n", value ? "set" : "clear",
			reg, (egpio->cached_values >> shift) & ei->reg_mask);

	spin_lock_irqsave(&ei->lock, flag);
	if (value)
		egpio->cached_values |= (1 << offset);
	else
		egpio->cached_values &= ~(1 << offset);
	egpio_writew((egpio->cached_values >> shift) & ei->reg_mask, ei, reg);
	spin_unlock_irqrestore(&ei->lock, flag);
}

static int egpio_direction_output(struct gpio_chip *chip,
					unsigned offset, int value)
{
	struct egpio_chip *egpio;

	egpio = gpiochip_get_data(chip);
	if (test_bit(offset, &egpio->is_out)) {
		egpio_set(chip, offset, value);
		return 0;
	} else {
		return -EINVAL;
	}
}

static int egpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
	struct egpio_chip *egpio;

	egpio = gpiochip_get_data(chip);

	return !test_bit(offset, &egpio->is_out);
}

static void egpio_write_cache(struct egpio_info *ei)
{
	int               i;
	struct egpio_chip *egpio;
	int               shift;

	for (i = 0; i < ei->nchips; i++) {
		egpio = &(ei->chip[i]);
		if (!egpio->is_out)
			continue;

		for (shift = 0; shift < egpio->chip.ngpio;
				shift += (1<<ei->reg_shift)) {

			int reg = egpio->reg_start + egpio_pos(ei, shift);

			if (!((egpio->is_out >> shift) & ei->reg_mask))
				continue;

			pr_debug("EGPIO: setting %x to %x, was %x\n", reg,
				(egpio->cached_values >> shift) & ei->reg_mask,
				egpio_readw(ei, reg));

			egpio_writew((egpio->cached_values >> shift)
					& ei->reg_mask, ei, reg);
		}
	}
}


/*
 * Setup
 */

static int __init egpio_probe(struct platform_device *pdev)
{
	struct htc_egpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
	struct resource   *res;
	struct egpio_info *ei;
	struct gpio_chip  *chip;
	unsigned int      irq, irq_end;
	int               i;
	int               ret;

	/* Initialize ei data structure. */
	ei = devm_kzalloc(&pdev->dev, sizeof(*ei), GFP_KERNEL);
	if (!ei)
		return -ENOMEM;

	spin_lock_init(&ei->lock);

	/* Find chained irq */
	ret = -EINVAL;
	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (res)
		ei->chained_irq = res->start;

	/* Map egpio chip into virtual address space. */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		goto fail;
	ei->base_addr = devm_ioremap_nocache(&pdev->dev, res->start,
					     resource_size(res));
	if (!ei->base_addr)
		goto fail;
	pr_debug("EGPIO phys=%08x virt=%p\n", (u32)res->start, ei->base_addr);

	if ((pdata->bus_width != 16) && (pdata->bus_width != 32))
		goto fail;
	ei->bus_shift = fls(pdata->bus_width - 1) - 3;
	pr_debug("bus_shift = %d\n", ei->bus_shift);

	if ((pdata->reg_width != 8) && (pdata->reg_width != 16))
		goto fail;
	ei->reg_shift = fls(pdata->reg_width - 1);
	pr_debug("reg_shift = %d\n", ei->reg_shift);

	ei->reg_mask = (1 << pdata->reg_width) - 1;

	platform_set_drvdata(pdev, ei);

	ei->nchips = pdata->num_chips;
	ei->chip = devm_kzalloc(&pdev->dev,
				sizeof(struct egpio_chip) * ei->nchips,
				GFP_KERNEL);
	if (!ei->chip) {
		ret = -ENOMEM;
		goto fail;
	}
	for (i = 0; i < ei->nchips; i++) {
		ei->chip[i].reg_start = pdata->chip[i].reg_start;
		ei->chip[i].cached_values = pdata->chip[i].initial_values;
		ei->chip[i].is_out = pdata->chip[i].direction;
		ei->chip[i].dev = &(pdev->dev);
		chip = &(ei->chip[i].chip);
		chip->label           = "htc-egpio";
		chip->parent          = &pdev->dev;
		chip->owner           = THIS_MODULE;
		chip->get             = egpio_get;
		chip->set             = egpio_set;
		chip->direction_input = egpio_direction_input;
		chip->direction_output = egpio_direction_output;
		chip->get_direction   = egpio_get_direction;
		chip->base            = pdata->chip[i].gpio_base;
		chip->ngpio           = pdata->chip[i].num_gpios;

		gpiochip_add_data(chip, &ei->chip[i]);
	}

	/* Set initial pin values */
	egpio_write_cache(ei);

	ei->irq_start = pdata->irq_base;
	ei->nirqs = pdata->num_irqs;
	ei->ack_register = pdata->ack_register;

	if (ei->chained_irq) {
		/* Setup irq handlers */
		ei->ack_write = 0xFFFF;
		if (pdata->invert_acks)
			ei->ack_write = 0;
		irq_end = ei->irq_start + ei->nirqs;
		for (irq = ei->irq_start; irq < irq_end; irq++) {
			irq_set_chip_and_handler(irq, &egpio_muxed_chip,
						 handle_simple_irq);
			irq_set_chip_data(irq, ei);
			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
		}
		irq_set_irq_type(ei->chained_irq, IRQ_TYPE_EDGE_RISING);
		irq_set_chained_handler_and_data(ei->chained_irq,
						 egpio_handler, ei);
		ack_irqs(ei);

		device_init_wakeup(&pdev->dev, 1);
	}

	return 0;

fail:
	printk(KERN_ERR "EGPIO failed to setup\n");
	return ret;
}

#ifdef CONFIG_PM
static int egpio_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct egpio_info *ei = platform_get_drvdata(pdev);

	if (ei->chained_irq && device_may_wakeup(&pdev->dev))
		enable_irq_wake(ei->chained_irq);
	return 0;
}

static int egpio_resume(struct platform_device *pdev)
{
	struct egpio_info *ei = platform_get_drvdata(pdev);

	if (ei->chained_irq && device_may_wakeup(&pdev->dev))
		disable_irq_wake(ei->chained_irq);

	/* Update registers from the cache, in case
	   the CPLD was powered off during suspend */
	egpio_write_cache(ei);
	return 0;
}
#else
#define egpio_suspend NULL
#define egpio_resume NULL
#endif


static struct platform_driver egpio_driver = {
	.driver = {
		.name = "htc-egpio",
		.suppress_bind_attrs = true,
	},
	.suspend      = egpio_suspend,
	.resume       = egpio_resume,
};

static int __init egpio_init(void)
{
	return platform_driver_probe(&egpio_driver, egpio_probe);
}
/* start early for dependencies */
subsys_initcall(egpio_init);
OpenPOWER on IntegriCloud