1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2021-2023 Digiteq Automotive
4 * author: Martin Tuma <martin.tuma@digiteqautomotive.com>
5 *
6 * The i2c module unifies the I2C access to the serializes/deserializes. The I2C
7 * chips on the GMSL module use 16b addressing, the FPDL3 chips use standard
8 * 8b addressing.
9 */
10
11#include "mgb4_i2c.h"
12
13static int read_r16(struct i2c_client *client, u16 reg, u8 *val, int len)
14{
15 int ret;
16 u8 buf[2];
17 struct i2c_msg msg[2] = {
18 {
19 .addr = client->addr,
20 .flags = 0,
21 .len = 2,
22 .buf = buf,
23 }, {
24 .addr = client->addr,
25 .flags = I2C_M_RD,
26 .len = len,
27 .buf = val,
28 }
29 };
30
31 buf[0] = (reg >> 8) & 0xff;
32 buf[1] = (reg >> 0) & 0xff;
33
34 ret = i2c_transfer(adap: client->adapter, msgs: msg, num: 2);
35 if (ret < 0)
36 return ret;
37 else if (ret != 2)
38 return -EREMOTEIO;
39 else
40 return 0;
41}
42
43static int write_r16(struct i2c_client *client, u16 reg, const u8 *val, int len)
44{
45 int ret;
46 u8 buf[4];
47 struct i2c_msg msg[1] = {
48 {
49 .addr = client->addr,
50 .flags = 0,
51 .len = 2 + len,
52 .buf = buf,
53 }
54 };
55
56 if (2 + len > sizeof(buf))
57 return -EINVAL;
58
59 buf[0] = (reg >> 8) & 0xff;
60 buf[1] = (reg >> 0) & 0xff;
61 memcpy(&buf[2], val, len);
62
63 ret = i2c_transfer(adap: client->adapter, msgs: msg, num: 1);
64 if (ret < 0)
65 return ret;
66 else if (ret != 1)
67 return -EREMOTEIO;
68 else
69 return 0;
70}
71
72int mgb4_i2c_init(struct mgb4_i2c_client *client, struct i2c_adapter *adap,
73 struct i2c_board_info const *info, int addr_size)
74{
75 client->client = i2c_new_client_device(adap, info);
76 if (IS_ERR(ptr: client->client))
77 return PTR_ERR(ptr: client->client);
78
79 client->addr_size = addr_size;
80
81 return 0;
82}
83
84void mgb4_i2c_free(struct mgb4_i2c_client *client)
85{
86 i2c_unregister_device(client: client->client);
87}
88
89s32 mgb4_i2c_read_byte(struct mgb4_i2c_client *client, u16 reg)
90{
91 int ret;
92 u8 b;
93
94 if (client->addr_size == 8)
95 return i2c_smbus_read_byte_data(client: client->client, command: reg);
96
97 ret = read_r16(client: client->client, reg, val: &b, len: 1);
98 if (ret < 0)
99 return ret;
100
101 return (s32)b;
102}
103
104s32 mgb4_i2c_write_byte(struct mgb4_i2c_client *client, u16 reg, u8 val)
105{
106 if (client->addr_size == 8)
107 return i2c_smbus_write_byte_data(client: client->client, command: reg, value: val);
108 else
109 return write_r16(client: client->client, reg, val: &val, len: 1);
110}
111
112s32 mgb4_i2c_mask_byte(struct mgb4_i2c_client *client, u16 reg, u8 mask, u8 val)
113{
114 s32 ret;
115
116 if (mask != 0xFF) {
117 ret = mgb4_i2c_read_byte(client, reg);
118 if (ret < 0)
119 return ret;
120 val |= (u8)ret & ~mask;
121 }
122
123 return mgb4_i2c_write_byte(client, reg, val);
124}
125
126int mgb4_i2c_configure(struct mgb4_i2c_client *client,
127 const struct mgb4_i2c_kv *values, size_t count)
128{
129 size_t i;
130 s32 res;
131
132 for (i = 0; i < count; i++) {
133 res = mgb4_i2c_mask_byte(client, reg: values[i].reg, mask: values[i].mask,
134 val: values[i].val);
135 if (res < 0)
136 return res;
137 }
138
139 return 0;
140}
141

source code of linux/drivers/media/pci/mgb4/mgb4_i2c.c