summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpio-ws16c48.c
blob: eaa71d440ccf66a581410d1e35e62e260e39ddcb (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
/*
 * GPIO driver for the WinSystems WS16C48
 * Copyright (C) 2016 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/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 WS16C48_EXTENT 16
#define MAX_NUM_WS16C48 max_num_isa_dev(WS16C48_EXTENT)

static unsigned int base[MAX_NUM_WS16C48];
static unsigned int num_ws16c48;
module_param_array(base, uint, &num_ws16c48, 0);
MODULE_PARM_DESC(base, "WinSystems WS16C48 base addresses");

static unsigned int irq[MAX_NUM_WS16C48];
module_param_array(irq, uint, NULL, 0);
MODULE_PARM_DESC(irq, "WinSystems WS16C48 interrupt line numbers");

/**
 * struct ws16c48_gpio - GPIO device private data structure
 * @chip:	instance of the gpio_chip
 * @io_state:	bit I/O state (whether bit is set to input or output)
 * @out_state:	output bits state
 * @lock:	synchronization lock to prevent I/O race conditions
 * @irq_mask:	I/O bits affected by interrupts
 * @flow_mask:	IRQ flow type mask for the respective I/O bits
 * @base:	base port address of the GPIO device
 * @irq:	Interrupt line number
 */
struct ws16c48_gpio {
	struct gpio_chip chip;
	unsigned char io_state[6];
	unsigned char out_state[6];
	spinlock_t lock;
	unsigned long irq_mask;
	unsigned long flow_mask;
	unsigned base;
	unsigned irq;
};

static int ws16c48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
	const unsigned port = offset / 8;
	const unsigned mask = BIT(offset % 8);

	return !!(ws16c48gpio->io_state[port] & mask);
}

static int ws16c48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
	const unsigned port = offset / 8;
	const unsigned mask = BIT(offset % 8);
	unsigned long flags;

	spin_lock_irqsave(&ws16c48gpio->lock, flags);

	ws16c48gpio->io_state[port] |= mask;
	ws16c48gpio->out_state[port] &= ~mask;
	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);

	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

	return 0;
}

static int ws16c48_gpio_direction_output(struct gpio_chip *chip,
	unsigned offset, int value)
{
	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
	const unsigned port = offset / 8;
	const unsigned mask = BIT(offset % 8);
	unsigned long flags;

	spin_lock_irqsave(&ws16c48gpio->lock, flags);

	ws16c48gpio->io_state[port] &= ~mask;
	if (value)
		ws16c48gpio->out_state[port] |= mask;
	else
		ws16c48gpio->out_state[port] &= ~mask;
	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);

	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

	return 0;
}

static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
	const unsigned port = offset / 8;
	const unsigned mask = BIT(offset % 8);
	unsigned long flags;
	unsigned port_state;

	spin_lock_irqsave(&ws16c48gpio->lock, flags);

	/* ensure that GPIO is set for input */
	if (!(ws16c48gpio->io_state[port] & mask)) {
		spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
		return -EINVAL;
	}

	port_state = inb(ws16c48gpio->base + port);

	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

	return !!(port_state & mask);
}

static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
	const unsigned port = offset / 8;
	const unsigned mask = BIT(offset % 8);
	unsigned long flags;

	spin_lock_irqsave(&ws16c48gpio->lock, flags);

	/* ensure that GPIO is set for output */
	if (ws16c48gpio->io_state[port] & mask) {
		spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
		return;
	}

	if (value)
		ws16c48gpio->out_state[port] |= mask;
	else
		ws16c48gpio->out_state[port] &= ~mask;
	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);

	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}

static void ws16c48_irq_ack(struct irq_data *data)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
	const unsigned long offset = irqd_to_hwirq(data);
	const unsigned port = offset / 8;
	const unsigned mask = BIT(offset % 8);
	unsigned long flags;
	unsigned port_state;

	/* only the first 3 ports support interrupts */
	if (port > 2)
		return;

	spin_lock_irqsave(&ws16c48gpio->lock, flags);

	port_state = ws16c48gpio->irq_mask >> (8*port);

	outb(0x80, ws16c48gpio->base + 7);
	outb(port_state & ~mask, ws16c48gpio->base + 8 + port);
	outb(port_state | mask, ws16c48gpio->base + 8 + port);
	outb(0xC0, ws16c48gpio->base + 7);

	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}

static void ws16c48_irq_mask(struct irq_data *data)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
	const unsigned long offset = irqd_to_hwirq(data);
	const unsigned long mask = BIT(offset);
	const unsigned port = offset / 8;
	unsigned long flags;

	/* only the first 3 ports support interrupts */
	if (port > 2)
		return;

	spin_lock_irqsave(&ws16c48gpio->lock, flags);

	ws16c48gpio->irq_mask &= ~mask;

	outb(0x80, ws16c48gpio->base + 7);
	outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
	outb(0xC0, ws16c48gpio->base + 7);

	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}

static void ws16c48_irq_unmask(struct irq_data *data)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
	const unsigned long offset = irqd_to_hwirq(data);
	const unsigned long mask = BIT(offset);
	const unsigned port = offset / 8;
	unsigned long flags;

	/* only the first 3 ports support interrupts */
	if (port > 2)
		return;

	spin_lock_irqsave(&ws16c48gpio->lock, flags);

	ws16c48gpio->irq_mask |= mask;

	outb(0x80, ws16c48gpio->base + 7);
	outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
	outb(0xC0, ws16c48gpio->base + 7);

	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}

static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
	const unsigned long offset = irqd_to_hwirq(data);
	const unsigned long mask = BIT(offset);
	const unsigned port = offset / 8;
	unsigned long flags;

	/* only the first 3 ports support interrupts */
	if (port > 2)
		return -EINVAL;

	spin_lock_irqsave(&ws16c48gpio->lock, flags);

	switch (flow_type) {
	case IRQ_TYPE_NONE:
		break;
	case IRQ_TYPE_EDGE_RISING:
		ws16c48gpio->flow_mask |= mask;
		break;
	case IRQ_TYPE_EDGE_FALLING:
		ws16c48gpio->flow_mask &= ~mask;
		break;
	default:
		spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
		return -EINVAL;
	}

	outb(0x40, ws16c48gpio->base + 7);
	outb(ws16c48gpio->flow_mask >> (8*port), ws16c48gpio->base + 8 + port);
	outb(0xC0, ws16c48gpio->base + 7);

	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

	return 0;
}

static struct irq_chip ws16c48_irqchip = {
	.name = "ws16c48",
	.irq_ack = ws16c48_irq_ack,
	.irq_mask = ws16c48_irq_mask,
	.irq_unmask = ws16c48_irq_unmask,
	.irq_set_type = ws16c48_irq_set_type
};

static irqreturn_t ws16c48_irq_handler(int irq, void *dev_id)
{
	struct ws16c48_gpio *const ws16c48gpio = dev_id;
	struct gpio_chip *const chip = &ws16c48gpio->chip;
	unsigned long int_pending;
	unsigned long port;
	unsigned long int_id;
	unsigned long gpio;

	int_pending = inb(ws16c48gpio->base + 6) & 0x7;
	if (!int_pending)
		return IRQ_NONE;

	/* loop until all pending interrupts are handled */
	do {
		for_each_set_bit(port, &int_pending, 3) {
			int_id = inb(ws16c48gpio->base + 8 + port);
			for_each_set_bit(gpio, &int_id, 8)
				generic_handle_irq(irq_find_mapping(
					chip->irqdomain, gpio + 8*port));
		}

		int_pending = inb(ws16c48gpio->base + 6) & 0x7;
	} while (int_pending);

	return IRQ_HANDLED;
}

static int ws16c48_probe(struct device *dev, unsigned int id)
{
	struct ws16c48_gpio *ws16c48gpio;
	const char *const name = dev_name(dev);
	int err;

	ws16c48gpio = devm_kzalloc(dev, sizeof(*ws16c48gpio), GFP_KERNEL);
	if (!ws16c48gpio)
		return -ENOMEM;

	if (!devm_request_region(dev, base[id], WS16C48_EXTENT, name)) {
		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
			base[id], base[id] + WS16C48_EXTENT);
		return -EBUSY;
	}

	ws16c48gpio->chip.label = name;
	ws16c48gpio->chip.parent = dev;
	ws16c48gpio->chip.owner = THIS_MODULE;
	ws16c48gpio->chip.base = -1;
	ws16c48gpio->chip.ngpio = 48;
	ws16c48gpio->chip.get_direction = ws16c48_gpio_get_direction;
	ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input;
	ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;
	ws16c48gpio->chip.get = ws16c48_gpio_get;
	ws16c48gpio->chip.set = ws16c48_gpio_set;
	ws16c48gpio->base = base[id];
	ws16c48gpio->irq = irq[id];

	spin_lock_init(&ws16c48gpio->lock);

	dev_set_drvdata(dev, ws16c48gpio);

	err = gpiochip_add_data(&ws16c48gpio->chip, ws16c48gpio);
	if (err) {
		dev_err(dev, "GPIO registering failed (%d)\n", err);
		return err;
	}

	/* Disable IRQ by default */
	outb(0x80, base[id] + 7);
	outb(0, base[id] + 8);
	outb(0, base[id] + 9);
	outb(0, base[id] + 10);
	outb(0xC0, base[id] + 7);

	err = gpiochip_irqchip_add(&ws16c48gpio->chip, &ws16c48_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], ws16c48_irq_handler, IRQF_SHARED, name,
		ws16c48gpio);
	if (err) {
		dev_err(dev, "IRQ handler registering failed (%d)\n", err);
		goto err_gpiochip_remove;
	}

	return 0;

err_gpiochip_remove:
	gpiochip_remove(&ws16c48gpio->chip);
	return err;
}

static int ws16c48_remove(struct device *dev, unsigned int id)
{
	struct ws16c48_gpio *const ws16c48gpio = dev_get_drvdata(dev);

	free_irq(ws16c48gpio->irq, ws16c48gpio);
	gpiochip_remove(&ws16c48gpio->chip);

	return 0;
}

static struct isa_driver ws16c48_driver = {
	.probe = ws16c48_probe,
	.driver = {
		.name = "ws16c48"
	},
	.remove = ws16c48_remove
};

module_isa_driver(ws16c48_driver, num_ws16c48);

MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("WinSystems WS16C48 GPIO driver");
MODULE_LICENSE("GPL v2");