243 lines
6.0 KiB
C
243 lines
6.0 KiB
C
/* ------------------------------------------------------------------------ *
|
|
* i2c-parport-light.c I2C bus over parallel port *
|
|
* ------------------------------------------------------------------------ *
|
|
Copyright (C) 2003-2007 Jean Delvare <khali@linux-fr.org>
|
|
|
|
Based on older i2c-velleman.c driver
|
|
Copyright (C) 1995-2000 Simon G. Vogl
|
|
With some changes from:
|
|
Frodo Looijaard <frodol@dds.nl>
|
|
Kyösti Mälkki <kmalkki@cc.hut.fi>
|
|
|
|
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/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/ioport.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/i2c-algo-bit.h>
|
|
#include <asm/io.h>
|
|
#include "i2c-parport.h"
|
|
|
|
#define DEFAULT_BASE 0x378
|
|
#define DRVNAME "i2c-parport-light"
|
|
|
|
static struct platform_device *pdev;
|
|
|
|
static u16 base;
|
|
module_param(base, ushort, 0);
|
|
MODULE_PARM_DESC(base, "Base I/O address");
|
|
|
|
/* ----- Low-level parallel port access ----------------------------------- */
|
|
|
|
static inline void port_write(unsigned char p, unsigned char d)
|
|
{
|
|
outb(d, base+p);
|
|
}
|
|
|
|
static inline unsigned char port_read(unsigned char p)
|
|
{
|
|
return inb(base+p);
|
|
}
|
|
|
|
/* ----- Unified line operation functions --------------------------------- */
|
|
|
|
static inline void line_set(int state, const struct lineop *op)
|
|
{
|
|
u8 oldval = port_read(op->port);
|
|
|
|
/* Touch only the bit(s) needed */
|
|
if ((op->inverted && !state) || (!op->inverted && state))
|
|
port_write(op->port, oldval | op->val);
|
|
else
|
|
port_write(op->port, oldval & ~op->val);
|
|
}
|
|
|
|
static inline int line_get(const struct lineop *op)
|
|
{
|
|
u8 oldval = port_read(op->port);
|
|
|
|
return ((op->inverted && (oldval & op->val) != op->val)
|
|
|| (!op->inverted && (oldval & op->val) == op->val));
|
|
}
|
|
|
|
/* ----- I2C algorithm call-back functions and structures ----------------- */
|
|
|
|
static void parport_setscl(void *data, int state)
|
|
{
|
|
line_set(state, &adapter_parm[type].setscl);
|
|
}
|
|
|
|
static void parport_setsda(void *data, int state)
|
|
{
|
|
line_set(state, &adapter_parm[type].setsda);
|
|
}
|
|
|
|
static int parport_getscl(void *data)
|
|
{
|
|
return line_get(&adapter_parm[type].getscl);
|
|
}
|
|
|
|
static int parport_getsda(void *data)
|
|
{
|
|
return line_get(&adapter_parm[type].getsda);
|
|
}
|
|
|
|
/* Encapsulate the functions above in the correct structure
|
|
Note that getscl will be set to NULL by the attaching code for adapters
|
|
that cannot read SCL back */
|
|
static struct i2c_algo_bit_data parport_algo_data = {
|
|
.setsda = parport_setsda,
|
|
.setscl = parport_setscl,
|
|
.getsda = parport_getsda,
|
|
.getscl = parport_getscl,
|
|
.udelay = 50,
|
|
.timeout = HZ,
|
|
};
|
|
|
|
/* ----- Driver registration ---------------------------------------------- */
|
|
|
|
static struct i2c_adapter parport_adapter = {
|
|
.owner = THIS_MODULE,
|
|
.class = I2C_CLASS_HWMON,
|
|
.id = I2C_HW_B_LP,
|
|
.algo_data = &parport_algo_data,
|
|
.name = "Parallel port adapter (light)",
|
|
};
|
|
|
|
static int __devinit i2c_parport_probe(struct platform_device *pdev)
|
|
{
|
|
int err;
|
|
|
|
/* Reset hardware to a sane state (SCL and SDA high) */
|
|
parport_setsda(NULL, 1);
|
|
parport_setscl(NULL, 1);
|
|
/* Other init if needed (power on...) */
|
|
if (adapter_parm[type].init.val)
|
|
line_set(1, &adapter_parm[type].init);
|
|
|
|
parport_adapter.dev.parent = &pdev->dev;
|
|
err = i2c_bit_add_bus(&parport_adapter);
|
|
if (err)
|
|
dev_err(&pdev->dev, "Unable to register with I2C\n");
|
|
return err;
|
|
}
|
|
|
|
static int __devexit i2c_parport_remove(struct platform_device *pdev)
|
|
{
|
|
i2c_del_adapter(&parport_adapter);
|
|
|
|
/* Un-init if needed (power off...) */
|
|
if (adapter_parm[type].init.val)
|
|
line_set(0, &adapter_parm[type].init);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver i2c_parport_driver = {
|
|
.driver = {
|
|
.owner = THIS_MODULE,
|
|
.name = DRVNAME,
|
|
},
|
|
.probe = i2c_parport_probe,
|
|
.remove = __devexit_p(i2c_parport_remove),
|
|
};
|
|
|
|
static int __init i2c_parport_device_add(u16 address)
|
|
{
|
|
int err;
|
|
|
|
pdev = platform_device_alloc(DRVNAME, -1);
|
|
if (!pdev) {
|
|
err = -ENOMEM;
|
|
printk(KERN_ERR DRVNAME ": Device allocation failed\n");
|
|
goto exit;
|
|
}
|
|
|
|
err = platform_device_add(pdev);
|
|
if (err) {
|
|
printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n",
|
|
err);
|
|
goto exit_device_put;
|
|
}
|
|
|
|
return 0;
|
|
|
|
exit_device_put:
|
|
platform_device_put(pdev);
|
|
exit:
|
|
return err;
|
|
}
|
|
|
|
static int __init i2c_parport_init(void)
|
|
{
|
|
int err;
|
|
|
|
if (type < 0) {
|
|
printk(KERN_ERR DRVNAME ": adapter type unspecified\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
if (type >= ARRAY_SIZE(adapter_parm)) {
|
|
printk(KERN_ERR DRVNAME ": invalid type (%d)\n", type);
|
|
return -ENODEV;
|
|
}
|
|
|
|
if (base == 0) {
|
|
pr_info(DRVNAME ": using default base 0x%x\n", DEFAULT_BASE);
|
|
base = DEFAULT_BASE;
|
|
}
|
|
|
|
if (!request_region(base, 3, DRVNAME))
|
|
return -EBUSY;
|
|
|
|
if (!adapter_parm[type].getscl.val)
|
|
parport_algo_data.getscl = NULL;
|
|
|
|
/* Sets global pdev as a side effect */
|
|
err = i2c_parport_device_add(base);
|
|
if (err)
|
|
goto exit_release;
|
|
|
|
err = platform_driver_register(&i2c_parport_driver);
|
|
if (err)
|
|
goto exit_device;
|
|
|
|
return 0;
|
|
|
|
exit_device:
|
|
platform_device_unregister(pdev);
|
|
exit_release:
|
|
release_region(base, 3);
|
|
return err;
|
|
}
|
|
|
|
static void __exit i2c_parport_exit(void)
|
|
{
|
|
platform_driver_unregister(&i2c_parport_driver);
|
|
platform_device_unregister(pdev);
|
|
release_region(base, 3);
|
|
}
|
|
|
|
MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
|
|
MODULE_DESCRIPTION("I2C bus over parallel port (light)");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
module_init(i2c_parport_init);
|
|
module_exit(i2c_parport_exit);
|