1 /*
2 * GPIO interface for IT8761E Super I/O chip
3 *
4 * Author: Denis Turischev <denis@compulab.co.il>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License 2 as published
8 * by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; see the file COPYING. If not, write to
17 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19
20 #include <linux/init.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/io.h>
24 #include <linux/errno.h>
25 #include <linux/ioport.h>
26
27 #include <linux/gpio.h>
28
29 #define SIO_CHIP_ID 0x8761
30 #define CHIP_ID_HIGH_BYTE 0x20
31 #define CHIP_ID_LOW_BYTE 0x21
32
33 static u8 ports[2] = { 0x2e, 0x4e };
34 static u8 port;
35
36 static DEFINE_SPINLOCK(sio_lock);
37
38 #define GPIO_NAME "it8761-gpio"
39 #define GPIO_BA_HIGH_BYTE 0x60
40 #define GPIO_BA_LOW_BYTE 0x61
41 #define GPIO_IOSIZE 4
42 #define GPIO1X_IO 0xf0
43 #define GPIO2X_IO 0xf1
44
45 static u16 gpio_ba;
46
read_reg(u8 addr,u8 port)47 static u8 read_reg(u8 addr, u8 port)
48 {
49 outb(addr, port);
50 return inb(port + 1);
51 }
52
write_reg(u8 data,u8 addr,u8 port)53 static void write_reg(u8 data, u8 addr, u8 port)
54 {
55 outb(addr, port);
56 outb(data, port + 1);
57 }
58
enter_conf_mode(u8 port)59 static void enter_conf_mode(u8 port)
60 {
61 outb(0x87, port);
62 outb(0x61, port);
63 outb(0x55, port);
64 outb((port == 0x2e) ? 0x55 : 0xaa, port);
65 }
66
exit_conf_mode(u8 port)67 static void exit_conf_mode(u8 port)
68 {
69 outb(0x2, port);
70 outb(0x2, port + 1);
71 }
72
enter_gpio_mode(u8 port)73 static void enter_gpio_mode(u8 port)
74 {
75 write_reg(0x2, 0x7, port);
76 }
77
it8761e_gpio_get(struct gpio_chip * gc,unsigned gpio_num)78 static int it8761e_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
79 {
80 u16 reg;
81 u8 bit;
82
83 bit = gpio_num % 8;
84 reg = (gpio_num >= 8) ? gpio_ba + 1 : gpio_ba;
85
86 return !!(inb(reg) & (1 << bit));
87 }
88
it8761e_gpio_direction_in(struct gpio_chip * gc,unsigned gpio_num)89 static int it8761e_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
90 {
91 u8 curr_dirs;
92 u8 io_reg, bit;
93
94 bit = gpio_num % 8;
95 io_reg = (gpio_num >= 8) ? GPIO2X_IO : GPIO1X_IO;
96
97 spin_lock(&sio_lock);
98
99 enter_conf_mode(port);
100 enter_gpio_mode(port);
101
102 curr_dirs = read_reg(io_reg, port);
103
104 if (curr_dirs & (1 << bit))
105 write_reg(curr_dirs & ~(1 << bit), io_reg, port);
106
107 exit_conf_mode(port);
108
109 spin_unlock(&sio_lock);
110 return 0;
111 }
112
it8761e_gpio_set(struct gpio_chip * gc,unsigned gpio_num,int val)113 static void it8761e_gpio_set(struct gpio_chip *gc,
114 unsigned gpio_num, int val)
115 {
116 u8 curr_vals, bit;
117 u16 reg;
118
119 bit = gpio_num % 8;
120 reg = (gpio_num >= 8) ? gpio_ba + 1 : gpio_ba;
121
122 spin_lock(&sio_lock);
123
124 curr_vals = inb(reg);
125 if (val)
126 outb(curr_vals | (1 << bit) , reg);
127 else
128 outb(curr_vals & ~(1 << bit), reg);
129
130 spin_unlock(&sio_lock);
131 }
132
it8761e_gpio_direction_out(struct gpio_chip * gc,unsigned gpio_num,int val)133 static int it8761e_gpio_direction_out(struct gpio_chip *gc,
134 unsigned gpio_num, int val)
135 {
136 u8 curr_dirs, io_reg, bit;
137
138 bit = gpio_num % 8;
139 io_reg = (gpio_num >= 8) ? GPIO2X_IO : GPIO1X_IO;
140
141 it8761e_gpio_set(gc, gpio_num, val);
142
143 spin_lock(&sio_lock);
144
145 enter_conf_mode(port);
146 enter_gpio_mode(port);
147
148 curr_dirs = read_reg(io_reg, port);
149
150 if (!(curr_dirs & (1 << bit)))
151 write_reg(curr_dirs | (1 << bit), io_reg, port);
152
153 exit_conf_mode(port);
154
155 spin_unlock(&sio_lock);
156 return 0;
157 }
158
159 static struct gpio_chip it8761e_gpio_chip = {
160 .label = GPIO_NAME,
161 .owner = THIS_MODULE,
162 .get = it8761e_gpio_get,
163 .direction_input = it8761e_gpio_direction_in,
164 .set = it8761e_gpio_set,
165 .direction_output = it8761e_gpio_direction_out,
166 };
167
it8761e_gpio_init(void)168 static int __init it8761e_gpio_init(void)
169 {
170 int i, id, err;
171
172 /* chip and port detection */
173 for (i = 0; i < ARRAY_SIZE(ports); i++) {
174 spin_lock(&sio_lock);
175 enter_conf_mode(ports[i]);
176
177 id = (read_reg(CHIP_ID_HIGH_BYTE, ports[i]) << 8) +
178 read_reg(CHIP_ID_LOW_BYTE, ports[i]);
179
180 exit_conf_mode(ports[i]);
181 spin_unlock(&sio_lock);
182
183 if (id == SIO_CHIP_ID) {
184 port = ports[i];
185 break;
186 }
187 }
188
189 if (!port)
190 return -ENODEV;
191
192 /* fetch GPIO base address */
193 enter_conf_mode(port);
194 enter_gpio_mode(port);
195 gpio_ba = (read_reg(GPIO_BA_HIGH_BYTE, port) << 8) +
196 read_reg(GPIO_BA_LOW_BYTE, port);
197 exit_conf_mode(port);
198
199 if (!request_region(gpio_ba, GPIO_IOSIZE, GPIO_NAME))
200 return -EBUSY;
201
202 it8761e_gpio_chip.base = -1;
203 it8761e_gpio_chip.ngpio = 16;
204
205 err = gpiochip_add(&it8761e_gpio_chip);
206 if (err < 0)
207 goto gpiochip_add_err;
208
209 return 0;
210
211 gpiochip_add_err:
212 release_region(gpio_ba, GPIO_IOSIZE);
213 gpio_ba = 0;
214 return err;
215 }
216
it8761e_gpio_exit(void)217 static void __exit it8761e_gpio_exit(void)
218 {
219 if (gpio_ba) {
220 int ret = gpiochip_remove(&it8761e_gpio_chip);
221
222 WARN(ret, "%s(): gpiochip_remove() failed, ret=%d\n",
223 __func__, ret);
224
225 release_region(gpio_ba, GPIO_IOSIZE);
226 gpio_ba = 0;
227 }
228 }
229 module_init(it8761e_gpio_init);
230 module_exit(it8761e_gpio_exit);
231
232 MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
233 MODULE_DESCRIPTION("GPIO interface for IT8761E Super I/O chip");
234 MODULE_LICENSE("GPL");
235