File: gpio-gpio-mm.c

package info (click to toggle)
linux 4.19.20-1
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 954,852 kB
  • sloc: ansic: 16,749,828; asm: 271,286; makefile: 38,257; sh: 32,808; perl: 27,671; python: 21,022; cpp: 5,063; yacc: 4,648; lex: 2,585; awk: 1,385; ruby: 25; sed: 5
file content (354 lines) | stat: -rw-r--r-- 10,762 bytes parent folder | download | duplicates (7)
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
/*
 * GPIO driver for the Diamond Systems GPIO-MM
 * 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.
 *
 * This driver supports the following Diamond Systems devices: GPIO-MM and
 * GPIO-MM-12.
 */
#include <linux/bitmap.h>
#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/isa.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>

#define GPIOMM_EXTENT 8
#define MAX_NUM_GPIOMM max_num_isa_dev(GPIOMM_EXTENT)

static unsigned int base[MAX_NUM_GPIOMM];
static unsigned int num_gpiomm;
module_param_hw_array(base, uint, ioport, &num_gpiomm, 0);
MODULE_PARM_DESC(base, "Diamond Systems GPIO-MM base addresses");

/**
 * struct gpiomm_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
 * @control:	Control registers state
 * @lock:	synchronization lock to prevent I/O race conditions
 * @base:	base port address of the GPIO device
 */
struct gpiomm_gpio {
	struct gpio_chip chip;
	unsigned char io_state[6];
	unsigned char out_state[6];
	unsigned char control[2];
	spinlock_t lock;
	unsigned int base;
};

static int gpiomm_gpio_get_direction(struct gpio_chip *chip,
	unsigned int offset)
{
	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
	const unsigned int port = offset / 8;
	const unsigned int mask = BIT(offset % 8);

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

static int gpiomm_gpio_direction_input(struct gpio_chip *chip,
	unsigned int offset)
{
	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
	const unsigned int io_port = offset / 8;
	const unsigned int control_port = io_port / 3;
	const unsigned int control_addr = gpiommgpio->base + 3 + control_port*4;
	unsigned long flags;
	unsigned int control;

	spin_lock_irqsave(&gpiommgpio->lock, flags);

	/* Check if configuring Port C */
	if (io_port == 2 || io_port == 5) {
		/* Port C can be configured by nibble */
		if (offset % 8 > 3) {
			gpiommgpio->io_state[io_port] |= 0xF0;
			gpiommgpio->control[control_port] |= BIT(3);
		} else {
			gpiommgpio->io_state[io_port] |= 0x0F;
			gpiommgpio->control[control_port] |= BIT(0);
		}
	} else {
		gpiommgpio->io_state[io_port] |= 0xFF;
		if (io_port == 0 || io_port == 3)
			gpiommgpio->control[control_port] |= BIT(4);
		else
			gpiommgpio->control[control_port] |= BIT(1);
	}

	control = BIT(7) | gpiommgpio->control[control_port];
	outb(control, control_addr);

	spin_unlock_irqrestore(&gpiommgpio->lock, flags);

	return 0;
}

static int gpiomm_gpio_direction_output(struct gpio_chip *chip,
	unsigned int offset, int value)
{
	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
	const unsigned int io_port = offset / 8;
	const unsigned int control_port = io_port / 3;
	const unsigned int mask = BIT(offset % 8);
	const unsigned int control_addr = gpiommgpio->base + 3 + control_port*4;
	const unsigned int out_port = (io_port > 2) ? io_port + 1 : io_port;
	unsigned long flags;
	unsigned int control;

	spin_lock_irqsave(&gpiommgpio->lock, flags);

	/* Check if configuring Port C */
	if (io_port == 2 || io_port == 5) {
		/* Port C can be configured by nibble */
		if (offset % 8 > 3) {
			gpiommgpio->io_state[io_port] &= 0x0F;
			gpiommgpio->control[control_port] &= ~BIT(3);
		} else {
			gpiommgpio->io_state[io_port] &= 0xF0;
			gpiommgpio->control[control_port] &= ~BIT(0);
		}
	} else {
		gpiommgpio->io_state[io_port] &= 0x00;
		if (io_port == 0 || io_port == 3)
			gpiommgpio->control[control_port] &= ~BIT(4);
		else
			gpiommgpio->control[control_port] &= ~BIT(1);
	}

	if (value)
		gpiommgpio->out_state[io_port] |= mask;
	else
		gpiommgpio->out_state[io_port] &= ~mask;

	control = BIT(7) | gpiommgpio->control[control_port];
	outb(control, control_addr);

	outb(gpiommgpio->out_state[io_port], gpiommgpio->base + out_port);

	spin_unlock_irqrestore(&gpiommgpio->lock, flags);

	return 0;
}

static int gpiomm_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
	const unsigned int port = offset / 8;
	const unsigned int mask = BIT(offset % 8);
	const unsigned int in_port = (port > 2) ? port + 1 : port;
	unsigned long flags;
	unsigned int port_state;

	spin_lock_irqsave(&gpiommgpio->lock, flags);

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

	port_state = inb(gpiommgpio->base + in_port);

	spin_unlock_irqrestore(&gpiommgpio->lock, flags);

	return !!(port_state & mask);
}

static int gpiomm_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
	unsigned long *bits)
{
	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
	size_t i;
	static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
	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;

	/* 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 = inb(gpiommgpio->base + ports[i]);

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

	return 0;
}

static void gpiomm_gpio_set(struct gpio_chip *chip, unsigned int offset,
	int value)
{
	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
	const unsigned int port = offset / 8;
	const unsigned int mask = BIT(offset % 8);
	const unsigned int out_port = (port > 2) ? port + 1 : port;
	unsigned long flags;

	spin_lock_irqsave(&gpiommgpio->lock, flags);

	if (value)
		gpiommgpio->out_state[port] |= mask;
	else
		gpiommgpio->out_state[port] &= ~mask;

	outb(gpiommgpio->out_state[port], gpiommgpio->base + out_port);

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

static void gpiomm_gpio_set_multiple(struct gpio_chip *chip,
	unsigned long *mask, unsigned long *bits)
{
	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
	unsigned int i;
	const unsigned int gpio_reg_size = 8;
	unsigned int port;
	unsigned int out_port;
	unsigned int bitmask;
	unsigned long flags;

	/* set bits are evaluated a gpio register size at a time */
	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
		/* no more set bits in this mask word; skip to the next word */
		if (!mask[BIT_WORD(i)]) {
			i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
			continue;
		}

		port = i / gpio_reg_size;
		out_port = (port > 2) ? port + 1 : port;
		bitmask = mask[BIT_WORD(i)] & bits[BIT_WORD(i)];

		spin_lock_irqsave(&gpiommgpio->lock, flags);

		/* update output state data and set device gpio register */
		gpiommgpio->out_state[port] &= ~mask[BIT_WORD(i)];
		gpiommgpio->out_state[port] |= bitmask;
		outb(gpiommgpio->out_state[port], gpiommgpio->base + out_port);

		spin_unlock_irqrestore(&gpiommgpio->lock, flags);

		/* prepare for next gpio register set */
		mask[BIT_WORD(i)] >>= gpio_reg_size;
		bits[BIT_WORD(i)] >>= gpio_reg_size;
	}
}

#define GPIOMM_NGPIO 48
static const char *gpiomm_names[GPIOMM_NGPIO] = {
	"Port 1A0", "Port 1A1", "Port 1A2", "Port 1A3", "Port 1A4", "Port 1A5",
	"Port 1A6", "Port 1A7", "Port 1B0", "Port 1B1", "Port 1B2", "Port 1B3",
	"Port 1B4", "Port 1B5", "Port 1B6", "Port 1B7", "Port 1C0", "Port 1C1",
	"Port 1C2", "Port 1C3", "Port 1C4", "Port 1C5", "Port 1C6", "Port 1C7",
	"Port 2A0", "Port 2A1", "Port 2A2", "Port 2A3", "Port 2A4", "Port 2A5",
	"Port 2A6", "Port 2A7", "Port 2B0", "Port 2B1", "Port 2B2", "Port 2B3",
	"Port 2B4", "Port 2B5", "Port 2B6", "Port 2B7", "Port 2C0", "Port 2C1",
	"Port 2C2", "Port 2C3", "Port 2C4", "Port 2C5", "Port 2C6", "Port 2C7",
};

static int gpiomm_probe(struct device *dev, unsigned int id)
{
	struct gpiomm_gpio *gpiommgpio;
	const char *const name = dev_name(dev);
	int err;

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

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

	gpiommgpio->chip.label = name;
	gpiommgpio->chip.parent = dev;
	gpiommgpio->chip.owner = THIS_MODULE;
	gpiommgpio->chip.base = -1;
	gpiommgpio->chip.ngpio = GPIOMM_NGPIO;
	gpiommgpio->chip.names = gpiomm_names;
	gpiommgpio->chip.get_direction = gpiomm_gpio_get_direction;
	gpiommgpio->chip.direction_input = gpiomm_gpio_direction_input;
	gpiommgpio->chip.direction_output = gpiomm_gpio_direction_output;
	gpiommgpio->chip.get = gpiomm_gpio_get;
	gpiommgpio->chip.get_multiple = gpiomm_gpio_get_multiple;
	gpiommgpio->chip.set = gpiomm_gpio_set;
	gpiommgpio->chip.set_multiple = gpiomm_gpio_set_multiple;
	gpiommgpio->base = base[id];

	spin_lock_init(&gpiommgpio->lock);

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

	/* initialize all GPIO as output */
	outb(0x80, base[id] + 3);
	outb(0x00, base[id]);
	outb(0x00, base[id] + 1);
	outb(0x00, base[id] + 2);
	outb(0x80, base[id] + 7);
	outb(0x00, base[id] + 4);
	outb(0x00, base[id] + 5);
	outb(0x00, base[id] + 6);

	return 0;
}

static struct isa_driver gpiomm_driver = {
	.probe = gpiomm_probe,
	.driver = {
		.name = "gpio-mm"
	},
};

module_isa_driver(gpiomm_driver, num_gpiomm);

MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("Diamond Systems GPIO-MM GPIO driver");
MODULE_LICENSE("GPL v2");