1 /* linux/drivers/i2c/busses/scx200_i2c.c
2
3 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
4
5 National Semiconductor SCx200 I2C bus on GPIO pins
6
7 Based on i2c-velleman.c Copyright (C) 1995-96, 2000 Simon G. Vogl
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 */
23
24 #include <linux/module.h>
25 #include <linux/errno.h>
26 #include <linux/kernel.h>
27 #include <linux/init.h>
28 #include <linux/i2c.h>
29 #include <linux/i2c-algo-bit.h>
30 #include <linux/io.h>
31
32 #include <linux/scx200_gpio.h>
33
34 #define NAME "scx200_i2c"
35
36 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
37 MODULE_DESCRIPTION("NatSemi SCx200 I2C Driver");
38 MODULE_LICENSE("GPL");
39
40 static int scl = CONFIG_SCx200_I2C_SCL;
41 static int sda = CONFIG_SCx200_I2C_SDA;
42
43 module_param(scl, int, 0);
44 MODULE_PARM_DESC(scl, "GPIO line for SCL");
45 module_param(sda, int, 0);
46 MODULE_PARM_DESC(sda, "GPIO line for SDA");
47
scx200_i2c_setscl(void * data,int state)48 static void scx200_i2c_setscl(void *data, int state)
49 {
50 scx200_gpio_set(scl, state);
51 }
52
scx200_i2c_setsda(void * data,int state)53 static void scx200_i2c_setsda(void *data, int state)
54 {
55 scx200_gpio_set(sda, state);
56 }
57
scx200_i2c_getscl(void * data)58 static int scx200_i2c_getscl(void *data)
59 {
60 return scx200_gpio_get(scl);
61 }
62
scx200_i2c_getsda(void * data)63 static int scx200_i2c_getsda(void *data)
64 {
65 return scx200_gpio_get(sda);
66 }
67
68 /* ------------------------------------------------------------------------
69 * Encapsulate the above functions in the correct operations structure.
70 * This is only done when more than one hardware adapter is supported.
71 */
72
73 static struct i2c_algo_bit_data scx200_i2c_data = {
74 .setsda = scx200_i2c_setsda,
75 .setscl = scx200_i2c_setscl,
76 .getsda = scx200_i2c_getsda,
77 .getscl = scx200_i2c_getscl,
78 .udelay = 10,
79 .timeout = HZ,
80 };
81
82 static struct i2c_adapter scx200_i2c_ops = {
83 .owner = THIS_MODULE,
84 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
85 .algo_data = &scx200_i2c_data,
86 .name = "NatSemi SCx200 I2C",
87 };
88
scx200_i2c_init(void)89 static int scx200_i2c_init(void)
90 {
91 pr_debug(NAME ": NatSemi SCx200 I2C Driver\n");
92
93 if (!scx200_gpio_present()) {
94 printk(KERN_ERR NAME ": no SCx200 gpio pins available\n");
95 return -ENODEV;
96 }
97
98 pr_debug(NAME ": SCL=GPIO%02u, SDA=GPIO%02u\n", scl, sda);
99
100 if (scl == -1 || sda == -1 || scl == sda) {
101 printk(KERN_ERR NAME ": scl and sda must be specified\n");
102 return -EINVAL;
103 }
104
105 /* Configure GPIOs as open collector outputs */
106 scx200_gpio_configure(scl, ~2, 5);
107 scx200_gpio_configure(sda, ~2, 5);
108
109 if (i2c_bit_add_bus(&scx200_i2c_ops) < 0) {
110 printk(KERN_ERR NAME ": adapter %s registration failed\n",
111 scx200_i2c_ops.name);
112 return -ENODEV;
113 }
114
115 return 0;
116 }
117
scx200_i2c_cleanup(void)118 static void scx200_i2c_cleanup(void)
119 {
120 i2c_del_adapter(&scx200_i2c_ops);
121 }
122
123 module_init(scx200_i2c_init);
124 module_exit(scx200_i2c_cleanup);
125
126 /*
127 Local variables:
128 compile-command: "make -k -C ../.. SUBDIRS=drivers/i2c modules"
129 c-basic-offset: 8
130 End:
131 */
132