aboutsummaryrefslogtreecommitdiff
path: root/drivers/gpio/gpio-it8761e.c
blob: dadfc245cf0993ac27615fee19ca66262f683458 (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
/*
 *  GPIO interface for IT8761E Super I/O chip
 *
 *  Author: Denis Turischev <denis@compulab.co.il>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License 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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/ioport.h>

#include <linux/gpio.h>

#define SIO_CHIP_ID		0x8761
#define CHIP_ID_HIGH_BYTE	0x20
#define CHIP_ID_LOW_BYTE	0x21

static u8 ports[2] = { 0x2e, 0x4e };
static u8 port;

static DEFINE_SPINLOCK(sio_lock);

#define GPIO_NAME		"it8761-gpio"
#define GPIO_BA_HIGH_BYTE	0x60
#define GPIO_BA_LOW_BYTE	0x61
#define GPIO_IOSIZE		4
#define GPIO1X_IO		0xf0
#define GPIO2X_IO		0xf1

static u16 gpio_ba;

static u8 read_reg(u8 addr, u8 port)
{
	outb(addr, port);
	return inb(port + 1);
}

static void write_reg(u8 data, u8 addr, u8 port)
{
	outb(addr, port);
	outb(data, port + 1);
}

static void enter_conf_mode(u8 port)
{
	outb(0x87, port);
	outb(0x61, port);
	outb(0x55, port);
	outb((port == 0x2e) ? 0x55 : 0xaa, port);
}

static void exit_conf_mode(u8 port)
{
	outb(0x2, port);
	outb(0x2, port + 1);
}

static void enter_gpio_mode(u8 port)
{
	write_reg(0x2, 0x7, port);
}

static int it8761e_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
{
	u16 reg;
	u8 bit;

	bit = gpio_num % 8;
	reg = (gpio_num >= 8) ? gpio_ba + 1 : gpio_ba;

	return !!(inb(reg) & (1 << bit));
}

static int it8761e_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
{
	u8 curr_dirs;
	u8 io_reg, bit;

	bit = gpio_num % 8;
	io_reg = (gpio_num >= 8) ? GPIO2X_IO : GPIO1X_IO;

	spin_lock(&sio_lock);

	enter_conf_mode(port);
	enter_gpio_mode(port);

	curr_dirs = read_reg(io_reg, port);

	if (curr_dirs & (1 << bit))
		write_reg(curr_dirs & ~(1 << bit), io_reg, port);

	exit_conf_mode(port);

	spin_unlock(&sio_lock);
	return 0;
}

static void it8761e_gpio_set(struct gpio_chip *gc,
				unsigned gpio_num, int val)
{
	u8 curr_vals, bit;
	u16 reg;

	bit = gpio_num % 8;
	reg = (gpio_num >= 8) ? gpio_ba + 1 : gpio_ba;

	spin_lock(&sio_lock);

	curr_vals = inb(reg);
	if (val)
		outb(curr_vals | (1 << bit) , reg);
	else
		outb(curr_vals & ~(1 << bit), reg);

	spin_unlock(&sio_lock);
}

static int it8761e_gpio_direction_out(struct gpio_chip *gc,
					unsigned gpio_num, int val)
{
	u8 curr_dirs, io_reg, bit;

	bit = gpio_num % 8;
	io_reg = (gpio_num >= 8) ? GPIO2X_IO : GPIO1X_IO;

	it8761e_gpio_set(gc, gpio_num, val);

	spin_lock(&sio_lock);

	enter_conf_mode(port);
	enter_gpio_mode(port);

	curr_dirs = read_reg(io_reg, port);

	if (!(curr_dirs & (1 << bit)))
		write_reg(curr_dirs | (1 << bit), io_reg, port);

	exit_conf_mode(port);

	spin_unlock(&sio_lock);
	return 0;
}

static struct gpio_chip it8761e_gpio_chip = {
	.label			= GPIO_NAME,
	.owner			= THIS_MODULE,
	.get			= it8761e_gpio_get,
	.direction_input	= it8761e_gpio_direction_in,
	.set			= it8761e_gpio_set,
	.direction_output	= it8761e_gpio_direction_out,
};

static int __init it8761e_gpio_init(void)
{
	int i, id, err;

	/* chip and port detection */
	for (i = 0; i < ARRAY_SIZE(ports); i++) {
		spin_lock(&sio_lock);
		enter_conf_mode(ports[i]);

		id = (read_reg(CHIP_ID_HIGH_BYTE, ports[i]) << 8) +
				read_reg(CHIP_ID_LOW_BYTE, ports[i]);

		exit_conf_mode(ports[i]);
		spin_unlock(&sio_lock);

		if (id == SIO_CHIP_ID) {
			port = ports[i];
			break;
		}
	}

	if (!port)
		return -ENODEV;

	/* fetch GPIO base address */
	enter_conf_mode(port);
	enter_gpio_mode(port);
	gpio_ba = (read_reg(GPIO_BA_HIGH_BYTE, port) << 8) +
				read_reg(GPIO_BA_LOW_BYTE, port);
	exit_conf_mode(port);

	if (!request_region(gpio_ba, GPIO_IOSIZE, GPIO_NAME))
		return -EBUSY;

	it8761e_gpio_chip.base = -1;
	it8761e_gpio_chip.ngpio = 16;

	err = gpiochip_add(&it8761e_gpio_chip);
	if (err < 0)
		goto gpiochip_add_err;

	return 0;

gpiochip_add_err:
	release_region(gpio_ba, GPIO_IOSIZE);
	gpio_ba = 0;
	return err;
}

static void __exit it8761e_gpio_exit(void)
{
	if (gpio_ba) {
		gpiochip_remove(&it8761e_gpio_chip);
		release_region(gpio_ba, GPIO_IOSIZE);
		gpio_ba = 0;
	}
}
module_init(it8761e_gpio_init);
module_exit(it8761e_gpio_exit);

MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
MODULE_DESCRIPTION("GPIO interface for IT8761E Super I/O chip");
MODULE_LICENSE("GPL");