tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* linux/drivers/i2c/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/config.h>
25#include <linux/module.h>
26#include <linux/errno.h>
27#include <linux/kernel.h>
28#include <linux/init.h>
29#include <linux/i2c.h>
30#include <linux/i2c-algo-bit.h>
31#include <asm/io.h>
32
33#include <linux/scx200_gpio.h>
34
35#define NAME "scx200_i2c"
36
37MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
38MODULE_DESCRIPTION("NatSemi SCx200 I2C Driver");
39MODULE_LICENSE("GPL");
40
41static int scl = CONFIG_SCx200_I2C_SCL;
42static int sda = CONFIG_SCx200_I2C_SDA;
43
44module_param(scl, int, 0);
45MODULE_PARM_DESC(scl, "GPIO line for SCL");
46module_param(sda, int, 0);
47MODULE_PARM_DESC(sda, "GPIO line for SDA");
48
49static void scx200_i2c_setscl(void *data, int state)
50{
51 scx200_gpio_set(scl, state);
52}
53
54static void scx200_i2c_setsda(void *data, int state)
55{
56 scx200_gpio_set(sda, state);
57}
58
59static int scx200_i2c_getscl(void *data)
60{
61 return scx200_gpio_get(scl);
62}
63
64static int scx200_i2c_getsda(void *data)
65{
66 return scx200_gpio_get(sda);
67}
68
69/* ------------------------------------------------------------------------
70 * Encapsulate the above functions in the correct operations structure.
71 * This is only done when more than one hardware adapter is supported.
72 */
73
74static struct i2c_algo_bit_data scx200_i2c_data = {
75 NULL,
76 scx200_i2c_setsda,
77 scx200_i2c_setscl,
78 scx200_i2c_getsda,
79 scx200_i2c_getscl,
80 10, 10, 100, /* waits, timeout */
81};
82
83static struct i2c_adapter scx200_i2c_ops = {
84 .owner = THIS_MODULE,
85 .algo_data = &scx200_i2c_data,
86 .name = "NatSemi SCx200 I2C",
87};
88
89static 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
118static void scx200_i2c_cleanup(void)
119{
120 i2c_bit_del_bus(&scx200_i2c_ops);
121}
122
123module_init(scx200_i2c_init);
124module_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*/