cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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tea6415c.c (3440B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2 /*
      3    tea6415c - i2c-driver for the tea6415c by SGS Thomson
      4
      5    Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
      6    Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
      7
      8    The tea6415c is a bus controlled video-matrix-switch
      9    with 8 inputs and 6 outputs.
     10    It is cascadable, i.e. it can be found at the addresses
     11    0x86 and 0x06 on the i2c-bus.
     12
     13    For detailed information download the specifications directly
     14    from SGS Thomson at http://www.st.com
     15
     16  */
     17
     18
     19#include <linux/module.h>
     20#include <linux/ioctl.h>
     21#include <linux/slab.h>
     22#include <linux/i2c.h>
     23#include <media/v4l2-device.h>
     24#include "tea6415c.h"
     25
     26MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
     27MODULE_DESCRIPTION("tea6415c driver");
     28MODULE_LICENSE("GPL");
     29
     30static int debug;
     31module_param(debug, int, 0644);
     32
     33MODULE_PARM_DESC(debug, "Debug level (0-1)");
     34
     35
     36/* makes a connection between the input-pin 'i' and the output-pin 'o' */
     37static int tea6415c_s_routing(struct v4l2_subdev *sd,
     38			      u32 i, u32 o, u32 config)
     39{
     40	struct i2c_client *client = v4l2_get_subdevdata(sd);
     41	u8 byte = 0;
     42	int ret;
     43
     44	v4l2_dbg(1, debug, sd, "i=%d, o=%d\n", i, o);
     45
     46	/* check if the pins are valid */
     47	if (0 == ((1 == i ||  3 == i ||  5 == i ||  6 == i ||  8 == i || 10 == i || 20 == i || 11 == i)
     48	      && (18 == o || 17 == o || 16 == o || 15 == o || 14 == o || 13 == o)))
     49		return -EINVAL;
     50
     51	/* to understand this, have a look at the tea6415c-specs (p.5) */
     52	switch (o) {
     53	case 18:
     54		byte = 0x00;
     55		break;
     56	case 14:
     57		byte = 0x20;
     58		break;
     59	case 16:
     60		byte = 0x10;
     61		break;
     62	case 17:
     63		byte = 0x08;
     64		break;
     65	case 15:
     66		byte = 0x18;
     67		break;
     68	case 13:
     69		byte = 0x28;
     70		break;
     71	}
     72
     73	switch (i) {
     74	case 5:
     75		byte |= 0x00;
     76		break;
     77	case 8:
     78		byte |= 0x04;
     79		break;
     80	case 3:
     81		byte |= 0x02;
     82		break;
     83	case 20:
     84		byte |= 0x06;
     85		break;
     86	case 6:
     87		byte |= 0x01;
     88		break;
     89	case 10:
     90		byte |= 0x05;
     91		break;
     92	case 1:
     93		byte |= 0x03;
     94		break;
     95	case 11:
     96		byte |= 0x07;
     97		break;
     98	}
     99
    100	ret = i2c_smbus_write_byte(client, byte);
    101	if (ret) {
    102		v4l2_dbg(1, debug, sd,
    103			"i2c_smbus_write_byte() failed, ret:%d\n", ret);
    104		return -EIO;
    105	}
    106	return ret;
    107}
    108
    109/* ----------------------------------------------------------------------- */
    110
    111static const struct v4l2_subdev_video_ops tea6415c_video_ops = {
    112	.s_routing = tea6415c_s_routing,
    113};
    114
    115static const struct v4l2_subdev_ops tea6415c_ops = {
    116	.video = &tea6415c_video_ops,
    117};
    118
    119static int tea6415c_probe(struct i2c_client *client,
    120			  const struct i2c_device_id *id)
    121{
    122	struct v4l2_subdev *sd;
    123
    124	/* let's see whether this adapter can support what we need */
    125	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE))
    126		return -EIO;
    127
    128	v4l_info(client, "chip found @ 0x%x (%s)\n",
    129			client->addr << 1, client->adapter->name);
    130	sd = devm_kzalloc(&client->dev, sizeof(*sd), GFP_KERNEL);
    131	if (sd == NULL)
    132		return -ENOMEM;
    133	v4l2_i2c_subdev_init(sd, client, &tea6415c_ops);
    134	return 0;
    135}
    136
    137static int tea6415c_remove(struct i2c_client *client)
    138{
    139	struct v4l2_subdev *sd = i2c_get_clientdata(client);
    140
    141	v4l2_device_unregister_subdev(sd);
    142	return 0;
    143}
    144
    145static const struct i2c_device_id tea6415c_id[] = {
    146	{ "tea6415c", 0 },
    147	{ }
    148};
    149MODULE_DEVICE_TABLE(i2c, tea6415c_id);
    150
    151static struct i2c_driver tea6415c_driver = {
    152	.driver = {
    153		.name	= "tea6415c",
    154	},
    155	.probe		= tea6415c_probe,
    156	.remove		= tea6415c_remove,
    157	.id_table	= tea6415c_id,
    158};
    159
    160module_i2c_driver(tea6415c_driver);