summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/scx200_i2c.c
blob: cb3ef5ac99fd06976c0145fd4be0399044f03b90 (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
/* linux/drivers/i2c/scx200_i2c.c 

   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>

   National Semiconductor SCx200 I2C bus on GPIO pins

   Based on i2c-velleman.c Copyright (C) 1995-96, 2000 Simon G. Vogl

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   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; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.		     
*/

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <asm/io.h>

#include <linux/scx200_gpio.h>

#define NAME "scx200_i2c"

MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
MODULE_DESCRIPTION("NatSemi SCx200 I2C Driver");
MODULE_LICENSE("GPL");

static int scl = CONFIG_SCx200_I2C_SCL;
static int sda = CONFIG_SCx200_I2C_SDA;

module_param(scl, int, 0);
MODULE_PARM_DESC(scl, "GPIO line for SCL");
module_param(sda, int, 0);
MODULE_PARM_DESC(sda, "GPIO line for SDA");

static void scx200_i2c_setscl(void *data, int state)
{
	scx200_gpio_set(scl, state);
}

static void scx200_i2c_setsda(void *data, int state)
{
	scx200_gpio_set(sda, state);
} 

static int scx200_i2c_getscl(void *data)
{
	return scx200_gpio_get(scl);
}

static int scx200_i2c_getsda(void *data)
{
	return scx200_gpio_get(sda);
}

/* ------------------------------------------------------------------------
 * Encapsulate the above functions in the correct operations structure.
 * This is only done when more than one hardware adapter is supported.
 */

static struct i2c_algo_bit_data scx200_i2c_data = {
	NULL,
	scx200_i2c_setsda,
	scx200_i2c_setscl,
	scx200_i2c_getsda,
	scx200_i2c_getscl,
	10, 10, 100,		/* waits, timeout */
};

static struct i2c_adapter scx200_i2c_ops = {
	.owner		   = THIS_MODULE,
	.algo_data	   = &scx200_i2c_data,
	.name	= "NatSemi SCx200 I2C",
};

static int scx200_i2c_init(void)
{
	pr_debug(NAME ": NatSemi SCx200 I2C Driver\n");

	if (!scx200_gpio_present()) {
		printk(KERN_ERR NAME ": no SCx200 gpio pins available\n");
		return -ENODEV;
	}

	pr_debug(NAME ": SCL=GPIO%02u, SDA=GPIO%02u\n", scl, sda);

	if (scl == -1 || sda == -1 || scl == sda) {
		printk(KERN_ERR NAME ": scl and sda must be specified\n");
		return -EINVAL;
	}

	/* Configure GPIOs as open collector outputs */
	scx200_gpio_configure(scl, ~2, 5);
	scx200_gpio_configure(sda, ~2, 5);

	if (i2c_bit_add_bus(&scx200_i2c_ops) < 0) {
		printk(KERN_ERR NAME ": adapter %s registration failed\n", 
		       scx200_i2c_ops.name);
		return -ENODEV;
	}
	
	return 0;
}

static void scx200_i2c_cleanup(void)
{
	i2c_bit_del_bus(&scx200_i2c_ops);
}

module_init(scx200_i2c_init);
module_exit(scx200_i2c_cleanup);

/*
    Local variables:
        compile-command: "make -k -C ../.. SUBDIRS=drivers/i2c modules"
        c-basic-offset: 8
    End:
*/
OpenPOWER on IntegriCloud