summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpio-104-idi-48.c
blob: 6c75c83baf5a82a3eb1da0c7a5d5949bcf31e43b (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
/*
 * GPIO driver for the ACCES 104-IDI-48 family
 * Copyright (C) 2015 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.
 *
 * This driver supports the following ACCES devices: 104-IDI-48A,
 * 104-IDI-48AC, 104-IDI-48B, and 104-IDI-48BC.
 */
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/irqdesc.h>
#include <linux/isa.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>

#define IDI_48_EXTENT 8
#define MAX_NUM_IDI_48 max_num_isa_dev(IDI_48_EXTENT)

static unsigned int base[MAX_NUM_IDI_48];
static unsigned int num_idi_48;
module_param_array(base, uint, &num_idi_48, 0);
MODULE_PARM_DESC(base, "ACCES 104-IDI-48 base addresses");

static unsigned int irq[MAX_NUM_IDI_48];
module_param_array(irq, uint, NULL, 0);
MODULE_PARM_DESC(irq, "ACCES 104-IDI-48 interrupt line numbers");

/**
 * struct idi_48_gpio - GPIO device private data structure
 * @chip:	instance of the gpio_chip
 * @lock:	synchronization lock to prevent I/O race conditions
 * @ack_lock:	synchronization lock to prevent IRQ handler race conditions
 * @irq_mask:	input bits affected by interrupts
 * @base:	base port address of the GPIO device
 * @irq:	Interrupt line number
 * @cos_enb:	Change-Of-State IRQ enable boundaries mask
 */
struct idi_48_gpio {
	struct gpio_chip chip;
	spinlock_t lock;
	spinlock_t ack_lock;
	unsigned char irq_mask[6];
	unsigned base;
	unsigned irq;
	unsigned char cos_enb;
};

static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
	return 1;
}

static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
	return 0;
}

static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
	unsigned i;
	const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 };
	unsigned base_offset;
	unsigned mask;

	for (i = 0; i < 48; i += 8)
		if (offset < i + 8) {
			base_offset = register_offset[i / 8];
			mask = BIT(offset - i);

			return !!(inb(idi48gpio->base + base_offset) & mask);
		}

	/* The following line should never execute since offset < 48 */
	return 0;
}

static void idi_48_irq_ack(struct irq_data *data)
{
}

static void idi_48_irq_mask(struct irq_data *data)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
	struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
	const unsigned offset = irqd_to_hwirq(data);
	unsigned i;
	unsigned mask;
	unsigned boundary;
	unsigned long flags;

	for (i = 0; i < 48; i += 8)
		if (offset < i + 8) {
			mask = BIT(offset - i);
			boundary = i / 8;

			idi48gpio->irq_mask[boundary] &= ~mask;

			if (!idi48gpio->irq_mask[boundary]) {
				idi48gpio->cos_enb &= ~BIT(boundary);

				spin_lock_irqsave(&idi48gpio->lock, flags);

				outb(idi48gpio->cos_enb, idi48gpio->base + 7);

				spin_unlock_irqrestore(&idi48gpio->lock, flags);
			}

			return;
		}
}

static void idi_48_irq_unmask(struct irq_data *data)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
	struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
	const unsigned offset = irqd_to_hwirq(data);
	unsigned i;
	unsigned mask;
	unsigned boundary;
	unsigned prev_irq_mask;
	unsigned long flags;

	for (i = 0; i < 48; i += 8)
		if (offset < i + 8) {
			mask = BIT(offset - i);
			boundary = i / 8;
			prev_irq_mask = idi48gpio->irq_mask[boundary];

			idi48gpio->irq_mask[boundary] |= mask;

			if (!prev_irq_mask) {
				idi48gpio->cos_enb |= BIT(boundary);

				spin_lock_irqsave(&idi48gpio->lock, flags);

				outb(idi48gpio->cos_enb, idi48gpio->base + 7);

				spin_unlock_irqrestore(&idi48gpio->lock, flags);
			}

			return;
		}
}

static int idi_48_irq_set_type(struct irq_data *data, unsigned 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 idi_48_irqchip = {
	.name = "104-idi-48",
	.irq_ack = idi_48_irq_ack,
	.irq_mask = idi_48_irq_mask,
	.irq_unmask = idi_48_irq_unmask,
	.irq_set_type = idi_48_irq_set_type
};

static irqreturn_t idi_48_irq_handler(int irq, void *dev_id)
{
	struct idi_48_gpio *const idi48gpio = dev_id;
	unsigned long cos_status;
	unsigned long boundary;
	unsigned long irq_mask;
	unsigned long bit_num;
	unsigned long gpio;
	struct gpio_chip *const chip = &idi48gpio->chip;

	spin_lock(&idi48gpio->ack_lock);

	spin_lock(&idi48gpio->lock);

	cos_status = inb(idi48gpio->base + 7);

	spin_unlock(&idi48gpio->lock);

	/* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
	if (cos_status & BIT(6)) {
		spin_unlock(&idi48gpio->ack_lock);
		return IRQ_NONE;
	}

	/* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
	cos_status &= 0x3F;

	for_each_set_bit(boundary, &cos_status, 6) {
		irq_mask = idi48gpio->irq_mask[boundary];

		for_each_set_bit(bit_num, &irq_mask, 8) {
			gpio = bit_num + boundary * 8;

			generic_handle_irq(irq_find_mapping(chip->irqdomain,
				gpio));
		}
	}

	spin_unlock(&idi48gpio->ack_lock);

	return IRQ_HANDLED;
}

static int idi_48_probe(struct device *dev, unsigned int id)
{
	struct idi_48_gpio *idi48gpio;
	const char *const name = dev_name(dev);
	int err;

	idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
	if (!idi48gpio)
		return -ENOMEM;

	if (!devm_request_region(dev, base[id], IDI_48_EXTENT, name)) {
		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
			base[id], base[id] + IDI_48_EXTENT);
		return -EBUSY;
	}

	idi48gpio->chip.label = name;
	idi48gpio->chip.parent = dev;
	idi48gpio->chip.owner = THIS_MODULE;
	idi48gpio->chip.base = -1;
	idi48gpio->chip.ngpio = 48;
	idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
	idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
	idi48gpio->chip.get = idi_48_gpio_get;
	idi48gpio->base = base[id];
	idi48gpio->irq = irq[id];

	spin_lock_init(&idi48gpio->lock);

	dev_set_drvdata(dev, idi48gpio);

	err = gpiochip_add_data(&idi48gpio->chip, idi48gpio);
	if (err) {
		dev_err(dev, "GPIO registering failed (%d)\n", err);
		return err;
	}

	/* Disable IRQ by default */
	outb(0, base[id] + 7);
	inb(base[id] + 7);

	err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_irqchip, 0,
		handle_edge_irq, IRQ_TYPE_NONE);
	if (err) {
		dev_err(dev, "Could not add irqchip (%d)\n", err);
		goto err_gpiochip_remove;
	}

	err = request_irq(irq[id], idi_48_irq_handler, IRQF_SHARED, name,
		idi48gpio);
	if (err) {
		dev_err(dev, "IRQ handler registering failed (%d)\n", err);
		goto err_gpiochip_remove;
	}

	return 0;

err_gpiochip_remove:
	gpiochip_remove(&idi48gpio->chip);
	return err;
}

static int idi_48_remove(struct device *dev, unsigned int id)
{
	struct idi_48_gpio *const idi48gpio = dev_get_drvdata(dev);

	free_irq(idi48gpio->irq, idi48gpio);
	gpiochip_remove(&idi48gpio->chip);

	return 0;
}

static struct isa_driver idi_48_driver = {
	.probe = idi_48_probe,
	.driver = {
		.name = "104-idi-48"
	},
	.remove = idi_48_remove
};
module_isa_driver(idi_48_driver, num_idi_48);

MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
MODULE_LICENSE("GPL v2");