blob: c3022a023449ec2012b7911c0be94d8f7446869b [file] [log] [blame]
/* linux/drivers/i2c/busses/scx200_i2c.c
Copyright (c) 2001,2002 Christer Weinigel <>
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
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 <>");
MODULE_DESCRIPTION("NatSemi SCx200 I2C Driver");
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 = {
.setsda = scx200_i2c_setsda,
.setscl = scx200_i2c_setscl,
.getsda = scx200_i2c_getsda,
.getscl = scx200_i2c_getscl,
.udelay = 10,
.timeout = 100,
static struct i2c_adapter scx200_i2c_ops = {
.owner = THIS_MODULE,
.id = I2C_HW_B_SCX200,
.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",;
return -ENODEV;
return 0;
static void scx200_i2c_cleanup(void)
Local variables:
compile-command: "make -k -C ../.. SUBDIRS=drivers/i2c modules"
c-basic-offset: 8