/*
tea6420 - i2c-driver for the tea6420 by SGS Thomson
Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
The tea6420 is a bus controlled audio-matrix with 5 stereo inputs,
4 stereo outputs and gain control for each output.
It is cascadable, i.e. it can be found at the adresses 0x98
and 0x9a on the i2c-bus.
For detailed informations download the specifications directly
from SGS Thomson at http://www.st.com
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/module.h>
#include <linux/ioctl.h>
#include <linux/i2c.h>
#include "tea6420.h"
static int debug = 0; /* insmod parameter */
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Turn on/off device debugging (default:off).");
#define dprintk(args...) \
do { if (debug) { printk("%s: %s()[%d]: ", KBUILD_MODNAME, __FUNCTION__, __LINE__); printk(args); } } while (0)
/* addresses to scan, found only at 0x4c and/or 0x4d (7-Bit) */
static unsigned short normal_i2c[] = { I2C_TEA6420_1, I2C_TEA6420_2, I2C_CLIENT_END };
/* magic definition of all other variables and things */
I2C_CLIENT_INSMOD;
static struct i2c_driver driver;
static struct i2c_client client_template;
/* make a connection between the input 'i' and the output 'o'
with gain 'g' for the tea6420-client 'client' (note: i = 6 means 'mute') */
static int tea6420_switch(struct i2c_client *client, int i, int o, int g)
{
u8 byte = 0;
int ret;
dprintk("adr:0x%02x, i:%d, o:%d, g:%d\n", client->addr, i, o, g);
/* check if the paramters are valid */
if (i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g % 2 != 0)
return -1;
byte = ((o - 1) << 5);
byte |= (i - 1);
/* to understand this, have a look at the tea6420-specs (p.5) */
switch (g) {
case 0:
byte |= (3 << 3);
break;
case 2:
byte |= (2 << 3);
break;
case 4:
byte |= (1 << 3);
break;
case 6:
break;
}
ret = i2c_smbus_write_byte(client, byte);
if (ret) {
dprintk("i2c_smbus_write_byte() failed, ret:%d\n", ret);
return -EIO;
}
return 0;
}
/* this function is called by i2c_probe */
static int tea6420_detect(struct i2c_adapter *adapter, int address, int kind)
{
struct i2c_client *client;
int err = 0, i = 0;
/* let's see whether this adapter can support what we need */
if (0 == i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE)) {
return 0;
}
/* allocate memory for client structure */
client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
if (0 == client) {
return -ENOMEM;
}
/* fill client structure */
memcpy(client, &client_template, sizeof(struct i2c_client));
client->addr = address;
client->adapter = adapter;
/* tell the i2c layer a new client has arrived */
if (0 != (err = i2c_attach_client(client))) {
kfree(client);
return err;
}
/* set initial values: set "mute"-input to all outputs at gain 0 */
err = 0;
for (i = 1; i < 5; i++) {
err += tea6420_switch(client, 6, i, 0);
}
if (err) {
dprintk("could not initialize tea6420\n");
kfree(client);
return -ENODEV;
}
printk("tea6420: detected @ 0x%02x on adapter %s\n", address, &client->adapter->name[0]);
return 0;
}
static int attach(struct i2c_adapter *adapter)
{
/* let's see whether this is a know adapter we can attach to */
if (adapter->id != I2C_HW_SAA7146) {
dprintk("refusing to probe on unknown adapter [name='%s',id=0x%x]\n", adapter->name, adapter->id);
return -ENODEV;
}
return i2c_probe(adapter, &addr_data, &tea6420_detect);
}
static int detach(struct i2c_client *client)
{
int ret = i2c_detach_client(client);
kfree(client);
return ret;
}
static int command(struct i2c_client *client, unsigned int cmd, void *arg)
{
struct tea6420_multiplex *a = (struct tea6420_multiplex *)arg;
int result = 0;
switch (cmd) {
case TEA6420_SWITCH:
result = tea6420_switch(client, a->in, a->out, a->gain);
break;
default:
return -ENOIOCTLCMD;
}
return result;
}
static struct i2c_driver driver = {
.driver = {
.name = "tea6420",
},
.id = I2C_DRIVERID_TEA6420,
.attach_adapter = attach,
.detach_client = detach,
.command = command,
};
static struct i2c_client client_template = {
.name = "tea6420",
.driver = &driver,
};
static int __init this_module_init(void)
{
return i2c_add_driver(&driver);
}
static void __exit this_module_exit(void)
{
i2c_del_driver(&driver);
}
module_init(this_module_init);
module_exit(this_module_exit);
MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
MODULE_DESCRIPTION("tea6420 driver");
MODULE_LICENSE("GPL");
