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 <asm/io.h>
31
32#include <linux/scx200_gpio.h>
33
34#define NAME "scx200_i2c"
35
36MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
37MODULE_DESCRIPTION("NatSemi SCx200 I2C Driver");
38MODULE_LICENSE("GPL");
39
40static int scl = CONFIG_SCx200_I2C_SCL;
41static int sda = CONFIG_SCx200_I2C_SDA;
42
43module_param(scl, int, 0);
44MODULE_PARM_DESC(scl, "GPIO line for SCL");
45module_param(sda, int, 0);
46MODULE_PARM_DESC(sda, "GPIO line for SDA");
47
48static void scx200_i2c_setscl(void *data, int state)
49{
50	scx200_gpio_set(scl, state);
51}
52
53static void scx200_i2c_setsda(void *data, int state)
54{
55	scx200_gpio_set(sda, state);
56}
57
58static int scx200_i2c_getscl(void *data)
59{
60	return scx200_gpio_get(scl);
61}
62
63static 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
73static 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	= 100,
80};
81
82static struct i2c_adapter scx200_i2c_ops = {
83	.owner		   = THIS_MODULE,
84	.id		   = I2C_HW_B_SCX200,
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_del_adapter(&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*/
132