/* 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_ADDR_TEA6420_1, I2C_ADDR_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 parameters 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 (!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");