hw/i2c/smbus_master.c

   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_transfer(bus, addr, 1)) {
  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_transfer(bus, addr, 0)) {
  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_transfer(bus, addr, 0)) {
  55         return -1;
  56     }
  57     i2c_send(bus, command);
  58     if (i2c_start_transfer(bus, addr, 1)) {
  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_transfer(bus, addr, 0)) {
  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_transfer(bus, addr, 0)) {
  83         return -1;
  84     }
  85     i2c_send(bus, command);
  86     if (i2c_start_transfer(bus, addr, 1)) {
  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_transfer(bus, addr, 0)) {
 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_transfer(bus, addr, 0)) {
 117             return -1;
 118         }
 119         i2c_send(bus, command);
 120     }
 121     if (i2c_start_transfer(bus, addr, 1)) {
 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_transfer(bus, addr, 0)) {
 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 }