/* ------------------------------------------------------------------------ *
* 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;
struct resource *res;
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
if (!request_region(res->start, res->end - res->start + 1, DRVNAME))
return -EBUSY;
/* 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");
goto exit_region;
}
return 0;
exit_region:
release_region(res->start, res->end - res->start + 1);
return err;
}
static int __devexit i2c_parport_remove(struct platform_device *pdev)
{
struct resource *res;
i2c_del_adapter(&parport_adapter);
/* Un-init if needed (power off...) */
if (adapter_parm[type].init.val)
line_set(0, &adapter_parm[type].init);
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
release_region(res->start, res->end - res->start + 1);
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)
{
struct resource res = {
.start = address,
.end = address + 2,
.name = DRVNAME,
.flags = IORESOURCE_IO,
};
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_resources(pdev, &res, 1);
if (err) {
printk(KERN_ERR DRVNAME ": Device resource addition failed "
"(%d)\n", err);
goto exit_device_put;
}
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 (!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;
err = platform_driver_register(&i2c_parport_driver);
if (err)
goto exit_device;
return 0;
exit_device:
platform_device_unregister(pdev);
exit:
return err;
}
static void __exit i2c_parport_exit(void)
{
platform_driver_unregister(&i2c_parport_driver);
platform_device_unregister(pdev);
}
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);
