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drv_generic_i2c.c
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drv_generic_i2c.c
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/* $Id$
* $URL$
*
* generic driver helper for i2c displays
*
* Copyright (C) 2005 Luis Correia <[email protected]>
* Copyright (C) 2005 The LCD4Linux Team <[email protected]>
*
* 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 int ctrldev;
static int datadev;
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_pre_write(int dev)
{
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);
return -EPIPE;
}
info("%s: initializing I2C slave device 0x%x for output", Driver, dev);
if (i2c_smbus_write_byte_data(i2c_device, 3, 0) < 0) {
error("%s: error initializing device 0x%x\n", Driver, dev);
close(i2c_device);
}
return 0;
}
int drv_generic_i2c_open(const char *section, const char *driver)
{
char *bus, *device;
udelay_init();
Section = (char *) section;
Driver = (char *) driver;
bus = cfg_get(Section, "Port", NULL);
device = cfg_get(Section, "Device", NULL);
ctrldev = atoi(device);
device = cfg_get(Section, "DDevice", NULL);
datadev = 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;
}
if (datadev) {
if (drv_generic_i2c_pre_write(datadev) < 0)
goto exit_error;
}
if (drv_generic_i2c_pre_write(ctrldev) < 0)
goto exit_error;
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_byte(const unsigned char data)
{
i2c_smbus_write_byte(i2c_device, data);
}
void drv_generic_i2c_data(const unsigned char data)
{
my_i2c_smbus_write_byte_data(i2c_device, data);
}
static void i2c_out(int dev, unsigned char val)
{
info("%s: initializing I2C 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);
return;
}
i2c_smbus_write_byte_data(i2c_device, 1, val);
}
void drv_generic_i2c_command(const unsigned char command, /*const */ unsigned char *data, const unsigned char length,
int bits)
{
if (bits == 4) {
i2c_smbus_write_block_data(i2c_device, command, length, data);
} else if (bits == 8 && datadev) {
/* set data on pins */
info("cmd: %08x, data0: %08x, data1: %08x\n", command, data[0], data[1]);
i2c_out(datadev, data[0]);
/* set enable pin including optional rs and rw */
i2c_out(ctrldev, command | data[1]);
/* unset enable pin including optional rs and rw */
i2c_out(ctrldev, command);
}
}