1 /*
2    tea6415c - i2c-driver for the tea6415c by SGS Thomson
3
4    Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
5
6    The tea6415c is a bus controlled video-matrix-switch
7    with 8 inputs and 6 outputs.
8    It is cascadable, i.e. it can be found at the addresses
9    0x86 and 0x06 on the i2c-bus.
10
11    For detailed informations download the specifications directly
12    from SGS Thomson at http://www.st.com
13
14    This program is free software; you can redistribute it and/or modify
15    it under the terms of the GNU General Public License vs published by
16    the Free Software Foundation; either version 2 of the License, or
17    (at your option) any later version.
18
19    This program is distributed in the hope that it will be useful,
20    but WITHOUT ANY WARRANTY; without even the implied warranty of
21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22    GNU General Public License for more details.
23
24    You should have received a copy of the GNU General Public License
25    along with this program; if not, write to the Free Software
26    Foundation, Inc., 675 Mvss Ave, Cambridge, MA 02139, USA.
27  */
28
29
30#include <linux/module.h>
31#include <linux/ioctl.h>
32#include <linux/i2c.h>
33
34#include "tea6415c.h"
35
36static int debug = 0;		/* insmod parameter */
37module_param(debug, int, 0644);
38MODULE_PARM_DESC(debug, "Turn on/off device debugging (default:off).");
39#define dprintk(args...) \
40	    do { if (debug) { printk("%s: %s()[%d]: ", KBUILD_MODNAME, __FUNCTION__, __LINE__); printk(args); } } while (0)
41
42#define TEA6415C_NUM_INPUTS	8
43#define TEA6415C_NUM_OUTPUTS	6
44
45/* addresses to scan, found only at 0x03 and/or 0x43 (7-bit) */
46static unsigned short normal_i2c[] = { I2C_TEA6415C_1, I2C_TEA6415C_2, I2C_CLIENT_END };
47
48/* magic definition of all other variables and things */
49I2C_CLIENT_INSMOD;
50
51static struct i2c_driver driver;
52static struct i2c_client client_template;
53
54/* this function is called by i2c_probe */
55static int detect(struct i2c_adapter *adapter, int address, int kind)
56{
57	struct i2c_client *client = NULL;
58	int err = 0;
59
60	/* let's see whether this adapter can support what we need */
61	if (0 == i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE)) {
62		return 0;
63	}
64
65	/* allocate memory for client structure */
66	client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
67	if (0 == client) {
68		return -ENOMEM;
69	}
70
71	/* fill client structure */
72	memcpy(client, &client_template, sizeof(struct i2c_client));
73	client->addr = address;
74	client->adapter = adapter;
75
76	/* tell the i2c layer a new client has arrived */
77	if (0 != (err = i2c_attach_client(client))) {
78		kfree(client);
79		return err;
80	}
81
82	printk("tea6415c: detected @ 0x%02x on adapter %s\n", address, &client->adapter->name[0]);
83
84	return 0;
85}
86
87static int attach(struct i2c_adapter *adapter)
88{
89	/* let's see whether this is a know adapter we can attach to */
90	if (adapter->id != I2C_HW_SAA7146) {
91		dprintk("refusing to probe on unknown adapter [name='%s',id=0x%x]\n", adapter->name, adapter->id);
92		return -ENODEV;
93	}
94
95	return i2c_probe(adapter, &addr_data, &detect);
96}
97
98static int detach(struct i2c_client *client)
99{
100	int ret = i2c_detach_client(client);
101	kfree(client);
102	return ret;
103}
104
105/* makes a connection between the input-pin 'i' and the output-pin 'o'
106   for the tea6415c-client 'client' */
107static int switch_matrix(struct i2c_client *client, int i, int o)
108{
109	u8 byte = 0;
110	int ret;
111
112	dprintk("adr:0x%02x, i:%d, o:%d\n", client->addr, i, o);
113
114	/* check if the pins are valid */
115	if (0 == ((1 == i ||  3 == i ||  5 == i ||  6 == i ||  8 == i || 10 == i || 20 == i || 11 == i)
116	      && (18 == o || 17 == o || 16 == o || 15 == o || 14 == o || 13 == o)))
117		return -1;
118
119	/* to understand this, have a look at the tea6415c-specs (p.5) */
120	switch (o) {
121	case 18:
122		byte = 0x00;
123		break;
124	case 14:
125		byte = 0x20;
126		break;
127	case 16:
128		byte = 0x10;
129		break;
130	case 17:
131		byte = 0x08;
132		break;
133	case 15:
134		byte = 0x18;
135		break;
136	case 13:
137		byte = 0x28;
138		break;
139	};
140
141	switch (i) {
142	case 5:
143		byte |= 0x00;
144		break;
145	case 8:
146		byte |= 0x04;
147		break;
148	case 3:
149		byte |= 0x02;
150		break;
151	case 20:
152		byte |= 0x06;
153		break;
154	case 6:
155		byte |= 0x01;
156		break;
157	case 10:
158		byte |= 0x05;
159		break;
160	case 1:
161		byte |= 0x03;
162		break;
163	case 11:
164		byte |= 0x07;
165		break;
166	};
167
168	ret = i2c_smbus_write_byte(client, byte);
169	if (ret) {
170		dprintk("i2c_smbus_write_byte() failed, ret:%d\n", ret);
171		return -EIO;
172	}
173
174	return ret;
175}
176
177static int command(struct i2c_client *client, unsigned int cmd, void *arg)
178{
179	struct tea6415c_multiplex *v = (struct tea6415c_multiplex *)arg;
180	int result = 0;
181
182	switch (cmd) {
183	case TEA6415C_SWITCH:
184		result = switch_matrix(client, v->in, v->out);
185		break;
186	default:
187		return -ENOIOCTLCMD;
188	}
189
190	return result;
191}
192
193static struct i2c_driver driver = {
194	.driver = {
195		.name = "tea6415c",
196	},
197	.id 	= I2C_DRIVERID_TEA6415C,
198	.attach_adapter	= attach,
199	.detach_client	= detach,
200	.command	= command,
201};
202
203static struct i2c_client client_template = {
204	.name = "tea6415c",
205	.driver = &driver,
206};
207
208static int __init this_module_init(void)
209{
210	return i2c_add_driver(&driver);
211}
212
213static void __exit this_module_exit(void)
214{
215	i2c_del_driver(&driver);
216}
217
218module_init(this_module_init);
219module_exit(this_module_exit);
220
221MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
222MODULE_DESCRIPTION("tea6415c driver");
223MODULE_LICENSE("GPL");
224