![Jan Engelhardt](/assets/img/avatar_default.png)
* Convert files to UTF-8. * Also correct some people's names (one example is Eißfeldt, which was found in a source file. Given that the author used an ß at all in a source file indicates that the real name has in fact a 'ß' and not an 'ss', which is commonly used as a substitute for 'ß' when limited to 7bit.) * Correct town names (Goettingen -> Göttingen) * Update Eberhard Mönkeberg's address (http://lkml.org/lkml/2007/1/8/313) Signed-off-by: Jan Engelhardt <jengelh@gmx.de> Signed-off-by: Adrian Bunk <bunk@kernel.org>
269 lines
7.4 KiB
C
269 lines
7.4 KiB
C
/* ------------------------------------------------------------------------ *
|
|
* i2c-parport.c I2C bus over parallel port *
|
|
* ------------------------------------------------------------------------ *
|
|
Copyright (C) 2003-2007 Jean Delvare <khali@linux-fr.org>
|
|
|
|
Based on older i2c-philips-par.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/parport.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/i2c-algo-bit.h>
|
|
#include "i2c-parport.h"
|
|
|
|
/* ----- Device list ------------------------------------------------------ */
|
|
|
|
struct i2c_par {
|
|
struct pardevice *pdev;
|
|
struct i2c_adapter adapter;
|
|
struct i2c_algo_bit_data algo_data;
|
|
struct i2c_par *next;
|
|
};
|
|
|
|
static struct i2c_par *adapter_list;
|
|
|
|
/* ----- Low-level parallel port access ----------------------------------- */
|
|
|
|
static void port_write_data(struct parport *p, unsigned char d)
|
|
{
|
|
parport_write_data(p, d);
|
|
}
|
|
|
|
static void port_write_control(struct parport *p, unsigned char d)
|
|
{
|
|
parport_write_control(p, d);
|
|
}
|
|
|
|
static unsigned char port_read_data(struct parport *p)
|
|
{
|
|
return parport_read_data(p);
|
|
}
|
|
|
|
static unsigned char port_read_status(struct parport *p)
|
|
{
|
|
return parport_read_status(p);
|
|
}
|
|
|
|
static unsigned char port_read_control(struct parport *p)
|
|
{
|
|
return parport_read_control(p);
|
|
}
|
|
|
|
static void (*port_write[])(struct parport *, unsigned char) = {
|
|
port_write_data,
|
|
NULL,
|
|
port_write_control,
|
|
};
|
|
|
|
static unsigned char (*port_read[])(struct parport *) = {
|
|
port_read_data,
|
|
port_read_status,
|
|
port_read_control,
|
|
};
|
|
|
|
/* ----- Unified line operation functions --------------------------------- */
|
|
|
|
static inline void line_set(struct parport *data, int state,
|
|
const struct lineop *op)
|
|
{
|
|
u8 oldval = port_read[op->port](data);
|
|
|
|
/* Touch only the bit(s) needed */
|
|
if ((op->inverted && !state) || (!op->inverted && state))
|
|
port_write[op->port](data, oldval | op->val);
|
|
else
|
|
port_write[op->port](data, oldval & ~op->val);
|
|
}
|
|
|
|
static inline int line_get(struct parport *data,
|
|
const struct lineop *op)
|
|
{
|
|
u8 oldval = port_read[op->port](data);
|
|
|
|
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((struct parport *) data, state, &adapter_parm[type].setscl);
|
|
}
|
|
|
|
static void parport_setsda(void *data, int state)
|
|
{
|
|
line_set((struct parport *) data, state, &adapter_parm[type].setsda);
|
|
}
|
|
|
|
static int parport_getscl(void *data)
|
|
{
|
|
return line_get((struct parport *) data, &adapter_parm[type].getscl);
|
|
}
|
|
|
|
static int parport_getsda(void *data)
|
|
{
|
|
return line_get((struct parport *) data, &adapter_parm[type].getsda);
|
|
}
|
|
|
|
/* Encapsulate the functions above in the correct structure.
|
|
Note that this is only a template, from which the real structures are
|
|
copied. The attaching code will set getscl to NULL for adapters that
|
|
cannot read SCL back, and will also make the data field point to
|
|
the parallel port structure. */
|
|
static struct i2c_algo_bit_data parport_algo_data = {
|
|
.setsda = parport_setsda,
|
|
.setscl = parport_setscl,
|
|
.getsda = parport_getsda,
|
|
.getscl = parport_getscl,
|
|
.udelay = 10, /* ~50 kbps */
|
|
.timeout = HZ,
|
|
};
|
|
|
|
/* ----- I2c and parallel port call-back functions and structures --------- */
|
|
|
|
static void i2c_parport_attach (struct parport *port)
|
|
{
|
|
struct i2c_par *adapter;
|
|
|
|
adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL);
|
|
if (adapter == NULL) {
|
|
printk(KERN_ERR "i2c-parport: Failed to kzalloc\n");
|
|
return;
|
|
}
|
|
|
|
pr_debug("i2c-parport: attaching to %s\n", port->name);
|
|
adapter->pdev = parport_register_device(port, "i2c-parport",
|
|
NULL, NULL, NULL, PARPORT_FLAG_EXCL, NULL);
|
|
if (!adapter->pdev) {
|
|
printk(KERN_ERR "i2c-parport: Unable to register with parport\n");
|
|
goto ERROR0;
|
|
}
|
|
|
|
/* Fill the rest of the structure */
|
|
adapter->adapter.owner = THIS_MODULE;
|
|
adapter->adapter.class = I2C_CLASS_HWMON;
|
|
adapter->adapter.id = I2C_HW_B_LP;
|
|
strlcpy(adapter->adapter.name, "Parallel port adapter",
|
|
sizeof(adapter->adapter.name));
|
|
adapter->algo_data = parport_algo_data;
|
|
/* Slow down if we can't sense SCL */
|
|
if (!adapter_parm[type].getscl.val) {
|
|
adapter->algo_data.getscl = NULL;
|
|
adapter->algo_data.udelay = 50; /* ~10 kbps */
|
|
}
|
|
adapter->algo_data.data = port;
|
|
adapter->adapter.algo_data = &adapter->algo_data;
|
|
adapter->adapter.dev.parent = port->physport->dev;
|
|
|
|
if (parport_claim_or_block(adapter->pdev) < 0) {
|
|
printk(KERN_ERR "i2c-parport: Could not claim parallel port\n");
|
|
goto ERROR1;
|
|
}
|
|
|
|
/* Reset hardware to a sane state (SCL and SDA high) */
|
|
parport_setsda(port, 1);
|
|
parport_setscl(port, 1);
|
|
/* Other init if needed (power on...) */
|
|
if (adapter_parm[type].init.val)
|
|
line_set(port, 1, &adapter_parm[type].init);
|
|
|
|
parport_release(adapter->pdev);
|
|
|
|
if (i2c_bit_add_bus(&adapter->adapter) < 0) {
|
|
printk(KERN_ERR "i2c-parport: Unable to register with I2C\n");
|
|
goto ERROR1;
|
|
}
|
|
|
|
/* Add the new adapter to the list */
|
|
adapter->next = adapter_list;
|
|
adapter_list = adapter;
|
|
return;
|
|
|
|
ERROR1:
|
|
parport_unregister_device(adapter->pdev);
|
|
ERROR0:
|
|
kfree(adapter);
|
|
}
|
|
|
|
static void i2c_parport_detach (struct parport *port)
|
|
{
|
|
struct i2c_par *adapter, *prev;
|
|
|
|
/* Walk the list */
|
|
for (prev = NULL, adapter = adapter_list; adapter;
|
|
prev = adapter, adapter = adapter->next) {
|
|
if (adapter->pdev->port == port) {
|
|
i2c_del_adapter(&adapter->adapter);
|
|
|
|
/* Un-init if needed (power off...) */
|
|
if (adapter_parm[type].init.val)
|
|
line_set(port, 0, &adapter_parm[type].init);
|
|
|
|
parport_unregister_device(adapter->pdev);
|
|
if (prev)
|
|
prev->next = adapter->next;
|
|
else
|
|
adapter_list = adapter->next;
|
|
kfree(adapter);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
static struct parport_driver i2c_parport_driver = {
|
|
.name = "i2c-parport",
|
|
.attach = i2c_parport_attach,
|
|
.detach = i2c_parport_detach,
|
|
};
|
|
|
|
/* ----- Module loading, unloading and information ------------------------ */
|
|
|
|
static int __init i2c_parport_init(void)
|
|
{
|
|
if (type < 0) {
|
|
printk(KERN_WARNING "i2c-parport: adapter type unspecified\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
if (type >= ARRAY_SIZE(adapter_parm)) {
|
|
printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type);
|
|
return -ENODEV;
|
|
}
|
|
|
|
return parport_register_driver(&i2c_parport_driver);
|
|
}
|
|
|
|
static void __exit i2c_parport_exit(void)
|
|
{
|
|
parport_unregister_driver(&i2c_parport_driver);
|
|
}
|
|
|
|
MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
|
|
MODULE_DESCRIPTION("I2C bus over parallel port");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
module_init(i2c_parport_init);
|
|
module_exit(i2c_parport_exit);
|