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 <asm/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 = 100, 80}; 81 82static struct i2c_adapter scx200_i2c_ops = { 83 .owner = THIS_MODULE, 84 .id = I2C_HW_B_SCX200, 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*/ 132