drv_generic_i2c.c


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
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173

/* $Id$
 * $URL$
 *
 * generic driver helper for i2c displays
 *
 * Copyright (C) 2005 Luis Correia <lfcorreia@users.sf.net>
 * Copyright (C) 2005 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
 *
 * This file is part of LCD4Linux.
 *
 * LCD4Linux 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, or (at your option)
 * any later version.
 *
 * LCD4Linux 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.
 *
 */

    /*
       DISCLAIMER!!!!

       The following code is WORK IN PROGRESS, since it basicly 'works for us...'

       (C) 2005 Paul Kamphuis & Luis Correia

       We have removed all of the delays from this code, as the I2C bus is slow enough...
       (maximum possible speed is 100KHz only)

     */

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <termios.h>
#include <fcntl.h>
#include <time.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>

#include "lcd4linux_i2c.h"
#include "debug.h"
#include "qprintf.h"
#include "cfg.h"
#include "udelay.h"
#include "drv_generic_i2c.h"


static char *Driver = "";
static char *Section = "";
static int i2c_device;


static void my_i2c_smbus_write_byte_data(const int device, const unsigned char val)
{
    struct i2c_smbus_ioctl_data args;
    union i2c_smbus_data data;
    args.read_write = I2C_SMBUS_WRITE;
    args.command = val;
    args.size = I2C_SMBUS_BYTE_DATA;
    data.byte = val;
    args.data = &data;
    if (ioctl(device, I2C_SMBUS, &args) < 0) {
	info("I2C: device %d IOCTL failed !\n", device);
    }
}

/* unused, ifdef'ed away to avoid compiler warning */
#if 0
static void my_i2c_smbus_read_byte_data(const int device, const unsigned char data)
{
    struct i2c_smbus_ioctl_data args;
    args.read_write = I2C_SMBUS_READ;
    args.command = data;
    args.size = I2C_SMBUS_BYTE;
    args.data = 0;
    ioctl(device, I2C_SMBUS, &args);
}
#endif


int drv_generic_i2c_open(const char *section, const char *driver)
{
    int dev;
    char *bus, *device;
    udelay_init();
    Section = (char *) section;
    Driver = (char *) driver;
    bus = cfg_get(Section, "Port", NULL);
    device = cfg_get(Section, "Device", NULL);
    dev = atoi(device);
    info("%s: initializing I2C bus %s", Driver, bus);
    if ((i2c_device = open(bus, O_WRONLY)) < 0) {
	error("%s: I2C bus %s open failed !\n", Driver, bus);
	goto exit_error;
    }
    info("%s: selecting slave device 0x%x", Driver, dev);
    if (ioctl(i2c_device, I2C_SLAVE, dev) < 0) {
	error("%s: error selecting slave device 0x%x\n", Driver, dev);
	goto exit_error;
    }

    info("%s: initializing I2C slave device 0x%x", Driver, dev);
    if (i2c_smbus_write_quick(i2c_device, I2C_SMBUS_WRITE) < 0) {
	error("%s: error initializing device 0x%x\n", Driver, dev);
	close(i2c_device);
    }

    return 0;

  exit_error:
    free(bus);
    free(device);
    close(i2c_device);
    return -1;
}

int drv_generic_i2c_close(void)
{
    close(i2c_device);
    return 0;
}

unsigned char drv_generic_i2c_wire(const char *name, const char *deflt)
{
    unsigned char w;
    char wire[256];
    char *s;
    qprintf(wire, sizeof(wire), "Wire.%s", name);
    s = cfg_get(Section, wire, deflt);
    if (strlen(s) == 3 && strncasecmp(s, "DB", 2) == 0 && s[2] >= '0' && s[2] <= '7') {
	w = s[2] - '0';
    } else if (strcasecmp(s, "GND") == 0) {
	w = 0;
    } else {
	error("%s: unknown signal <%s> for wire <%s>", Driver, s, name);
	error("%s: should be DB0..7 or GND", Driver);
	return 0xff;
    }
    free(s);
    if (w == 0) {
	info("%s: wiring: [DISPLAY:%s]<==>[i2c:GND]", Driver, name);
    } else {
	info("%s: wiring: [DISPLAY:%s]<==>[i2c:DB%d]", Driver, name, w);
    }
    w = 1 << w;
    return w;
}


void drv_generic_i2c_data(const unsigned char data)
{
    my_i2c_smbus_write_byte_data(i2c_device, data);
}


void drv_generic_i2c_command(const unsigned char command, /*const */ unsigned char *data, const unsigned char length)
{
    i2c_smbus_write_block_data(i2c_device, command, length, data);
}