diff options
Diffstat (limited to 'drivers/i2c/busses/scx200_i2c.c')
| -rw-r--r-- | drivers/i2c/busses/scx200_i2c.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/i2c/busses/scx200_i2c.c b/drivers/i2c/busses/scx200_i2c.c new file mode 100644 index 00000000000..27fbfecc414 --- /dev/null +++ b/drivers/i2c/busses/scx200_i2c.c @@ -0,0 +1,131 @@ +/* linux/drivers/i2c/scx200_i2c.c + + Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> + + 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 + 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. +*/ + +#include <linux/config.h> +#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 <wingel@nano-system.com>"); +MODULE_DESCRIPTION("NatSemi SCx200 I2C Driver"); +MODULE_LICENSE("GPL"); + +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 = { + NULL, + scx200_i2c_setsda, + scx200_i2c_setscl, + scx200_i2c_getsda, + scx200_i2c_getscl, + 10, 10, 100, /* waits, timeout */ +}; + +static struct i2c_adapter scx200_i2c_ops = { + .owner = THIS_MODULE, + .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", + scx200_i2c_ops.name); + return -ENODEV; + } + + return 0; +} + +static void scx200_i2c_cleanup(void) +{ + i2c_bit_del_bus(&scx200_i2c_ops); +} + +module_init(scx200_i2c_init); +module_exit(scx200_i2c_cleanup); + +/* + Local variables: + compile-command: "make -k -C ../.. SUBDIRS=drivers/i2c modules" + c-basic-offset: 8 + End: +*/ |