aboutsummaryrefslogtreecommitdiff
path: root/drivers/gpio/gpio-pci-idio-16.c
blob: 6b73497832231e8911302c425e904a85664eacf7 (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
/*
 * GPIO driver for the ACCES PCI-IDIO-16
 * Copyright (C) 2017 William Breathitt Gray
 *
 * 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.
 *
 * This program is distributed in the hope that 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.
 */
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/irqdesc.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/spinlock.h>
#include <linux/types.h>

/**
 * struct idio_16_gpio_reg - GPIO device registers structure
 * @out0_7:	Read: FET Drive Outputs 0-7
 *		Write: FET Drive Outputs 0-7
 * @in0_7:	Read: Isolated Inputs 0-7
 *		Write: Clear Interrupt
 * @irq_ctl:	Read: Enable IRQ
 *		Write: Disable IRQ
 * @filter_ctl:	Read: Activate Input Filters 0-15
 *		Write: Deactivate Input Filters 0-15
 * @out8_15:	Read: FET Drive Outputs 8-15
 *		Write: FET Drive Outputs 8-15
 * @in8_15:	Read: Isolated Inputs 8-15
 *		Write: Unused
 * @irq_status:	Read: Interrupt status
 *		Write: Unused
 */
struct idio_16_gpio_reg {
	u8 out0_7;
	u8 in0_7;
	u8 irq_ctl;
	u8 filter_ctl;
	u8 out8_15;
	u8 in8_15;
	u8 irq_status;
};

/**
 * struct idio_16_gpio - GPIO device private data structure
 * @chip:	instance of the gpio_chip
 * @lock:	synchronization lock to prevent I/O race conditions
 * @reg:	I/O address offset for the GPIO device registers
 * @irq_mask:	I/O bits affected by interrupts
 */
struct idio_16_gpio {
	struct gpio_chip chip;
	raw_spinlock_t lock;
	struct idio_16_gpio_reg __iomem *reg;
	unsigned long irq_mask;
};

static int idio_16_gpio_get_direction(struct gpio_chip *chip,
	unsigned int offset)
{
	if (offset > 15)
		return 1;

	return 0;
}

static int idio_16_gpio_direction_input(struct gpio_chip *chip,
	unsigned int offset)
{
	return 0;
}

static int idio_16_gpio_direction_output(struct gpio_chip *chip,
	unsigned int offset, int value)
{
	chip->set(chip, offset, value);
	return 0;
}

static int idio_16_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
	unsigned long mask = BIT(offset);

	if (offset < 8)
		return !!(ioread8(&idio16gpio->reg->out0_7) & mask);

	if (offset < 16)
		return !!(ioread8(&idio16gpio->reg->out8_15) & (mask >> 8));

	if (offset < 24)
		return !!(ioread8(&idio16gpio->reg->in0_7) & (mask >> 16));

	return !!(ioread8(&idio16gpio->reg->in8_15) & (mask >> 24));
}

static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
	unsigned long *mask, unsigned long *bits)
{
	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
	size_t i;
	const unsigned int gpio_reg_size = 8;
	unsigned int bits_offset;
	size_t word_index;
	unsigned int word_offset;
	unsigned long word_mask;
	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
	unsigned long port_state;
	void __iomem *ports[] = {
		&idio16gpio->reg->out0_7, &idio16gpio->reg->out8_15,
		&idio16gpio->reg->in0_7, &idio16gpio->reg->in8_15,
	};

	/* clear bits array to a clean slate */
	bitmap_zero(bits, chip->ngpio);

	/* get bits are evaluated a gpio port register at a time */
	for (i = 0; i < ARRAY_SIZE(ports); i++) {
		/* gpio offset in bits array */
		bits_offset = i * gpio_reg_size;

		/* word index for bits array */
		word_index = BIT_WORD(bits_offset);

		/* gpio offset within current word of bits array */
		word_offset = bits_offset % BITS_PER_LONG;

		/* mask of get bits for current gpio within current word */
		word_mask = mask[word_index] & (port_mask << word_offset);
		if (!word_mask) {
			/* no get bits in this port so skip to next one */
			continue;
		}

		/* read bits from current gpio port */
		port_state = ioread8(ports[i]);

		/* store acquired bits at respective bits array offset */
		bits[word_index] |= (port_state << word_offset) & word_mask;
	}

	return 0;
}

static void idio_16_gpio_set(struct gpio_chip *chip, unsigned int offset,
	int value)
{
	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
	unsigned int mask = BIT(offset);
	void __iomem *base;
	unsigned long flags;
	unsigned int out_state;

	if (offset > 15)
		return;

	if (offset > 7) {
		mask >>= 8;
		base = &idio16gpio->reg->out8_15;
	} else
		base = &idio16gpio->reg->out0_7;

	raw_spin_lock_irqsave(&idio16gpio->lock, flags);

	if (value)
		out_state = ioread8(base) | mask;
	else
		out_state = ioread8(base) & ~mask;

	iowrite8(out_state, base);

	raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}

static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
	unsigned long *mask, unsigned long *bits)
{
	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
	unsigned long flags;
	unsigned int out_state;

	raw_spin_lock_irqsave(&idio16gpio->lock, flags);

	/* process output lines 0-7 */
	if (*mask & 0xFF) {
		out_state = ioread8(&idio16gpio->reg->out0_7) & ~*mask;
		out_state |= *mask & *bits;
		iowrite8(out_state, &idio16gpio->reg->out0_7);
	}

	/* shift to next output line word */
	*mask >>= 8;

	/* process output lines 8-15 */
	if (*mask & 0xFF) {
		*bits >>= 8;
		out_state = ioread8(&idio16gpio->reg->out8_15) & ~*mask;
		out_state |= *mask & *bits;
		iowrite8(out_state, &idio16gpio->reg->out8_15);
	}

	raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}

static void idio_16_irq_ack(struct irq_data *data)
{
}

static void idio_16_irq_mask(struct irq_data *data)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
	const unsigned long mask = BIT(irqd_to_hwirq(data));
	unsigned long flags;

	idio16gpio->irq_mask &= ~mask;

	if (!idio16gpio->irq_mask) {
		raw_spin_lock_irqsave(&idio16gpio->lock, flags);

		iowrite8(0, &idio16gpio->reg->irq_ctl);

		raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
	}
}

static void idio_16_irq_unmask(struct irq_data *data)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
	const unsigned long mask = BIT(irqd_to_hwirq(data));
	const unsigned long prev_irq_mask = idio16gpio->irq_mask;
	unsigned long flags;

	idio16gpio->irq_mask |= mask;

	if (!prev_irq_mask) {
		raw_spin_lock_irqsave(&idio16gpio->lock, flags);

		ioread8(&idio16gpio->reg->irq_ctl);

		raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
	}
}

static int idio_16_irq_set_type(struct irq_data *data, unsigned int flow_type)
{
	/* The only valid irq types are none and both-edges */
	if (flow_type != IRQ_TYPE_NONE &&
		(flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
		return -EINVAL;

	return 0;
}

static struct irq_chip idio_16_irqchip = {
	.name = "pci-idio-16",
	.irq_ack = idio_16_irq_ack,
	.irq_mask = idio_16_irq_mask,
	.irq_unmask = idio_16_irq_unmask,
	.irq_set_type = idio_16_irq_set_type
};

static irqreturn_t idio_16_irq_handler(int irq, void *dev_id)
{
	struct idio_16_gpio *const idio16gpio = dev_id;
	unsigned int irq_status;
	struct gpio_chip *const chip = &idio16gpio->chip;
	int gpio;

	raw_spin_lock(&idio16gpio->lock);

	irq_status = ioread8(&idio16gpio->reg->irq_status);

	raw_spin_unlock(&idio16gpio->lock);

	/* Make sure our device generated IRQ */
	if (!(irq_status & 0x3) || !(irq_status & 0x4))
		return IRQ_NONE;

	for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio)
		generic_handle_irq(irq_find_mapping(chip->irq.domain, gpio));

	raw_spin_lock(&idio16gpio->lock);

	/* Clear interrupt */
	iowrite8(0, &idio16gpio->reg->in0_7);

	raw_spin_unlock(&idio16gpio->lock);

	return IRQ_HANDLED;
}

#define IDIO_16_NGPIO 32
static const char *idio_16_names[IDIO_16_NGPIO] = {
	"OUT0", "OUT1", "OUT2", "OUT3", "OUT4", "OUT5", "OUT6", "OUT7",
	"OUT8", "OUT9", "OUT10", "OUT11", "OUT12", "OUT13", "OUT14", "OUT15",
	"IIN0", "IIN1", "IIN2", "IIN3", "IIN4", "IIN5", "IIN6", "IIN7",
	"IIN8", "IIN9", "IIN10", "IIN11", "IIN12", "IIN13", "IIN14", "IIN15"
};

static int idio_16_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
	struct device *const dev = &pdev->dev;
	struct idio_16_gpio *idio16gpio;
	int err;
	const size_t pci_bar_index = 2;
	const char *const name = pci_name(pdev);

	idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL);
	if (!idio16gpio)
		return -ENOMEM;

	err = pcim_enable_device(pdev);
	if (err) {
		dev_err(dev, "Failed to enable PCI device (%d)\n", err);
		return err;
	}

	err = pcim_iomap_regions(pdev, BIT(pci_bar_index), name);
	if (err) {
		dev_err(dev, "Unable to map PCI I/O addresses (%d)\n", err);
		return err;
	}

	idio16gpio->reg = pcim_iomap_table(pdev)[pci_bar_index];

	/* Deactivate input filters */
	iowrite8(0, &idio16gpio->reg->filter_ctl);

	idio16gpio->chip.label = name;
	idio16gpio->chip.parent = dev;
	idio16gpio->chip.owner = THIS_MODULE;
	idio16gpio->chip.base = -1;
	idio16gpio->chip.ngpio = IDIO_16_NGPIO;
	idio16gpio->chip.names = idio_16_names;
	idio16gpio->chip.get_direction = idio_16_gpio_get_direction;
	idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
	idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
	idio16gpio->chip.get = idio_16_gpio_get;
	idio16gpio->chip.get_multiple = idio_16_gpio_get_multiple;
	idio16gpio->chip.set = idio_16_gpio_set;
	idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;

	raw_spin_lock_init(&idio16gpio->lock);

	err = devm_gpiochip_add_data(dev, &idio16gpio->chip, idio16gpio);
	if (err) {
		dev_err(dev, "GPIO registering failed (%d)\n", err);
		return err;
	}

	/* Disable IRQ by default and clear any pending interrupt */
	iowrite8(0, &idio16gpio->reg->irq_ctl);
	iowrite8(0, &idio16gpio->reg->in0_7);

	err = gpiochip_irqchip_add(&idio16gpio->chip, &idio_16_irqchip, 0,
		handle_edge_irq, IRQ_TYPE_NONE);
	if (err) {
		dev_err(dev, "Could not add irqchip (%d)\n", err);
		return err;
	}

	err = devm_request_irq(dev, pdev->irq, idio_16_irq_handler, IRQF_SHARED,
		name, idio16gpio);
	if (err) {
		dev_err(dev, "IRQ handler registering failed (%d)\n", err);
		return err;
	}

	return 0;
}

static const struct pci_device_id idio_16_pci_dev_id[] = {
	{ PCI_DEVICE(0x494F, 0x0DC8) }, { 0 }
};
MODULE_DEVICE_TABLE(pci, idio_16_pci_dev_id);

static struct pci_driver idio_16_driver = {
	.name = "pci-idio-16",
	.id_table = idio_16_pci_dev_id,
	.probe = idio_16_probe
};

module_pci_driver(idio_16_driver);

MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("ACCES PCI-IDIO-16 GPIO driver");
MODULE_LICENSE("GPL v2");