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1da177e4 LT |
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 | ||
37 | MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); | |
38 | MODULE_DESCRIPTION("NatSemi SCx200 I2C Driver"); | |
39 | MODULE_LICENSE("GPL"); | |
40 | ||
41 | static int scl = CONFIG_SCx200_I2C_SCL; | |
42 | static int sda = CONFIG_SCx200_I2C_SDA; | |
43 | ||
44 | module_param(scl, int, 0); | |
45 | MODULE_PARM_DESC(scl, "GPIO line for SCL"); | |
46 | module_param(sda, int, 0); | |
47 | MODULE_PARM_DESC(sda, "GPIO line for SDA"); | |
48 | ||
49 | static void scx200_i2c_setscl(void *data, int state) | |
50 | { | |
51 | scx200_gpio_set(scl, state); | |
52 | } | |
53 | ||
54 | static void scx200_i2c_setsda(void *data, int state) | |
55 | { | |
56 | scx200_gpio_set(sda, state); | |
57 | } | |
58 | ||
59 | static int scx200_i2c_getscl(void *data) | |
60 | { | |
61 | return scx200_gpio_get(scl); | |
62 | } | |
63 | ||
64 | static 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 | ||
74 | static 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 | ||
83 | static struct i2c_adapter scx200_i2c_ops = { | |
84 | .owner = THIS_MODULE, | |
85 | .algo_data = &scx200_i2c_data, | |
86 | .name = "NatSemi SCx200 I2C", | |
87 | }; | |
88 | ||
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 | ||
118 | static void scx200_i2c_cleanup(void) | |
119 | { | |
120 | i2c_bit_del_bus(&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 | */ |