1/* linux/drivers/i2c/busses/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/module.h>
 25#include <linux/errno.h>
 26#include <linux/kernel.h>
 27#include <linux/init.h>
 28#include <linux/i2c.h>
 29#include <linux/i2c-algo-bit.h>
 30#include <linux/io.h>
 31
 32#include <linux/scx200_gpio.h>
 33
 34#define NAME "scx200_i2c"
 35
 36MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
 37MODULE_DESCRIPTION("NatSemi SCx200 I2C Driver");
 38MODULE_LICENSE("GPL");
 39
 40static int scl = CONFIG_SCx200_I2C_SCL;
 41static int sda = CONFIG_SCx200_I2C_SDA;
 42
 43module_param(scl, int, 0);
 44MODULE_PARM_DESC(scl, "GPIO line for SCL");
 45module_param(sda, int, 0);
 46MODULE_PARM_DESC(sda, "GPIO line for SDA");
 47
 48static void scx200_i2c_setscl(void *data, int state)
 49{
 50	scx200_gpio_set(scl, state);
 51}
 52
 53static void scx200_i2c_setsda(void *data, int state)
 54{
 55	scx200_gpio_set(sda, state);
 56} 
 57
 58static int scx200_i2c_getscl(void *data)
 59{
 60	return scx200_gpio_get(scl);
 61}
 62
 63static int scx200_i2c_getsda(void *data)
 64{
 65	return scx200_gpio_get(sda);
 66}
 67
 68/* ------------------------------------------------------------------------
 69 * Encapsulate the above functions in the correct operations structure.
 70 * This is only done when more than one hardware adapter is supported.
 71 */
 72
 73static struct i2c_algo_bit_data scx200_i2c_data = {
 74	.setsda		= scx200_i2c_setsda,
 75	.setscl		= scx200_i2c_setscl,
 76	.getsda		= scx200_i2c_getsda,
 77	.getscl		= scx200_i2c_getscl,
 78	.udelay		= 10,
 79	.timeout	= HZ,
 80};
 81
 82static struct i2c_adapter scx200_i2c_ops = {
 83	.owner		   = THIS_MODULE,
 84	.class             = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 85	.algo_data	   = &scx200_i2c_data,
 86	.name	= "NatSemi SCx200 I2C",
 87};
 88
 89static 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
118static void scx200_i2c_cleanup(void)
119{
120	i2c_del_adapter(&scx200_i2c_ops);
121}
122
123module_init(scx200_i2c_init);
124module_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*/