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(client->adapter, msg, 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(client->adapter, msg, 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(client->client))
77		return PTR_ERR(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);
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, reg);
96
97	ret = read_r16(client->client, reg, &b, 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, reg, val);
108	else
109		return write_r16(client->client, reg, &val, 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, values[i].reg, values[i].mask,
134					 values[i].val);
135		if (res < 0)
136			return res;
137	}
138
139	return 0;
140}
141