qemu/hw/i2c/smbus_master.c
Philippe Mathieu-Daudé 90603c5b89 hw/i2c: Introduce i2c_start_recv() and i2c_start_send()
To ease reviewing code using the I2C bus API, introduce the
i2c_start_recv() and i2c_start_send() helpers which don't
take the confusing 'is_recv' boolean argument.

Use these new helpers in the SMBus / AUX bus models.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2021-07-08 14:15:01 -05:00

165 lines
3.4 KiB
C

/*
* QEMU SMBus host (master) emulation.
*
* This code emulates SMBus transactions from the master point of view,
* it runs the individual I2C transaction to do the SMBus protocol
* over I2C.
*
* Copyright (c) 2007 CodeSourcery.
* Written by Paul Brook
*
* This code is licensed under the LGPL.
*/
#include "qemu/osdep.h"
#include "hw/i2c/i2c.h"
#include "hw/i2c/smbus_master.h"
/* Master device commands. */
int smbus_quick_command(I2CBus *bus, uint8_t addr, int read)
{
if (i2c_start_transfer(bus, addr, read)) {
return -1;
}
i2c_end_transfer(bus);
return 0;
}
int smbus_receive_byte(I2CBus *bus, uint8_t addr)
{
uint8_t data;
if (i2c_start_recv(bus, addr)) {
return -1;
}
data = i2c_recv(bus);
i2c_nack(bus);
i2c_end_transfer(bus);
return data;
}
int smbus_send_byte(I2CBus *bus, uint8_t addr, uint8_t data)
{
if (i2c_start_send(bus, addr)) {
return -1;
}
i2c_send(bus, data);
i2c_end_transfer(bus);
return 0;
}
int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command)
{
uint8_t data;
if (i2c_start_send(bus, addr)) {
return -1;
}
i2c_send(bus, command);
if (i2c_start_recv(bus, addr)) {
i2c_end_transfer(bus);
return -1;
}
data = i2c_recv(bus);
i2c_nack(bus);
i2c_end_transfer(bus);
return data;
}
int smbus_write_byte(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t data)
{
if (i2c_start_send(bus, addr)) {
return -1;
}
i2c_send(bus, command);
i2c_send(bus, data);
i2c_end_transfer(bus);
return 0;
}
int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command)
{
uint16_t data;
if (i2c_start_send(bus, addr)) {
return -1;
}
i2c_send(bus, command);
if (i2c_start_recv(bus, addr)) {
i2c_end_transfer(bus);
return -1;
}
data = i2c_recv(bus);
data |= i2c_recv(bus) << 8;
i2c_nack(bus);
i2c_end_transfer(bus);
return data;
}
int smbus_write_word(I2CBus *bus, uint8_t addr, uint8_t command, uint16_t data)
{
if (i2c_start_send(bus, addr)) {
return -1;
}
i2c_send(bus, command);
i2c_send(bus, data & 0xff);
i2c_send(bus, data >> 8);
i2c_end_transfer(bus);
return 0;
}
int smbus_read_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
int len, bool recv_len, bool send_cmd)
{
int rlen;
int i;
if (send_cmd) {
if (i2c_start_send(bus, addr)) {
return -1;
}
i2c_send(bus, command);
}
if (i2c_start_recv(bus, addr)) {
if (send_cmd) {
i2c_end_transfer(bus);
}
return -1;
}
if (recv_len) {
rlen = i2c_recv(bus);
} else {
rlen = len;
}
if (rlen > len) {
rlen = 0;
}
for (i = 0; i < rlen; i++) {
data[i] = i2c_recv(bus);
}
i2c_nack(bus);
i2c_end_transfer(bus);
return rlen;
}
int smbus_write_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
int len, bool send_len)
{
int i;
if (len > 32) {
len = 32;
}
if (i2c_start_send(bus, addr)) {
return -1;
}
i2c_send(bus, command);
if (send_len) {
i2c_send(bus, len);
}
for (i = 0; i < len; i++) {
i2c_send(bus, data[i]);
}
i2c_end_transfer(bus);
return 0;
}