xref: /qemu/hw/i2c/smbus_master.c (revision 727385c4) 
1 /*
2  * QEMU SMBus host (master) emulation.
3  *
4  * This code emulates SMBus transactions from the master point of view,
5  * it runs the individual I2C transaction to do the SMBus protocol
6  * over I2C.
7  *
8  * Copyright (c) 2007 CodeSourcery.
9  * Written by Paul Brook
10  *
11  * This code is licensed under the LGPL.
12  */
13 
14 #include "qemu/osdep.h"
15 #include "hw/i2c/i2c.h"
16 #include "hw/i2c/smbus_master.h"
17 
18 /* Master device commands.  */
19 int smbus_quick_command(I2CBus *bus, uint8_t addr, int read)
20 {
21     if (i2c_start_transfer(bus, addr, read)) {
22         return -1;
23     }
24     i2c_end_transfer(bus);
25     return 0;
26 }
27 
28 int smbus_receive_byte(I2CBus *bus, uint8_t addr)
29 {
30     uint8_t data;
31 
32     if (i2c_start_recv(bus, addr)) {
33         return -1;
34     }
35     data = i2c_recv(bus);
36     i2c_nack(bus);
37     i2c_end_transfer(bus);
38     return data;
39 }
40 
41 int smbus_send_byte(I2CBus *bus, uint8_t addr, uint8_t data)
42 {
43     if (i2c_start_send(bus, addr)) {
44         return -1;
45     }
46     i2c_send(bus, data);
47     i2c_end_transfer(bus);
48     return 0;
49 }
50 
51 int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command)
52 {
53     uint8_t data;
54     if (i2c_start_send(bus, addr)) {
55         return -1;
56     }
57     i2c_send(bus, command);
58     if (i2c_start_recv(bus, addr)) {
59         i2c_end_transfer(bus);
60         return -1;
61     }
62     data = i2c_recv(bus);
63     i2c_nack(bus);
64     i2c_end_transfer(bus);
65     return data;
66 }
67 
68 int smbus_write_byte(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t data)
69 {
70     if (i2c_start_send(bus, addr)) {
71         return -1;
72     }
73     i2c_send(bus, command);
74     i2c_send(bus, data);
75     i2c_end_transfer(bus);
76     return 0;
77 }
78 
79 int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command)
80 {
81     uint16_t data;
82     if (i2c_start_send(bus, addr)) {
83         return -1;
84     }
85     i2c_send(bus, command);
86     if (i2c_start_recv(bus, addr)) {
87         i2c_end_transfer(bus);
88         return -1;
89     }
90     data = i2c_recv(bus);
91     data |= i2c_recv(bus) << 8;
92     i2c_nack(bus);
93     i2c_end_transfer(bus);
94     return data;
95 }
96 
97 int smbus_write_word(I2CBus *bus, uint8_t addr, uint8_t command, uint16_t data)
98 {
99     if (i2c_start_send(bus, addr)) {
100         return -1;
101     }
102     i2c_send(bus, command);
103     i2c_send(bus, data & 0xff);
104     i2c_send(bus, data >> 8);
105     i2c_end_transfer(bus);
106     return 0;
107 }
108 
109 int smbus_read_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
110                      int len, bool recv_len, bool send_cmd)
111 {
112     int rlen;
113     int i;
114 
115     if (send_cmd) {
116         if (i2c_start_send(bus, addr)) {
117             return -1;
118         }
119         i2c_send(bus, command);
120     }
121     if (i2c_start_recv(bus, addr)) {
122         if (send_cmd) {
123             i2c_end_transfer(bus);
124         }
125         return -1;
126     }
127     if (recv_len) {
128         rlen = i2c_recv(bus);
129     } else {
130         rlen = len;
131     }
132     if (rlen > len) {
133         rlen = 0;
134     }
135     for (i = 0; i < rlen; i++) {
136         data[i] = i2c_recv(bus);
137     }
138     i2c_nack(bus);
139     i2c_end_transfer(bus);
140     return rlen;
141 }
142 
143 int smbus_write_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
144                       int len, bool send_len)
145 {
146     int i;
147 
148     if (len > 32) {
149         len = 32;
150     }
151 
152     if (i2c_start_send(bus, addr)) {
153         return -1;
154     }
155     i2c_send(bus, command);
156     if (send_len) {
157         i2c_send(bus, len);
158     }
159     for (i = 0; i < len; i++) {
160         i2c_send(bus, data[i]);
161     }
162     i2c_end_transfer(bus);
163     return 0;
164 }
165