319 lines
7.8 KiB
C
319 lines
7.8 KiB
C
/*
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* QEMU SMBus device emulation.
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*
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* Copyright (c) 2007 CodeSourcery.
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* Written by Paul Brook
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*
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* This code is licenced under the LGPL.
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*/
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/* TODO: Implement PEC. */
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#include "hw.h"
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#include "i2c.h"
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#include "smbus.h"
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//#define DEBUG_SMBUS 1
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#ifdef DEBUG_SMBUS
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#define DPRINTF(fmt, ...) \
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do { printf("smbus(%02x): " fmt , dev->i2c.address, ## __VA_ARGS__); } while (0)
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#define BADF(fmt, ...) \
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do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__); exit(1);} while (0)
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#else
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#define DPRINTF(fmt, ...) do {} while(0)
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#define BADF(fmt, ...) \
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do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__);} while (0)
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#endif
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enum {
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SMBUS_IDLE,
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SMBUS_WRITE_DATA,
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SMBUS_RECV_BYTE,
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SMBUS_READ_DATA,
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SMBUS_DONE,
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SMBUS_CONFUSED = -1
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};
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static void smbus_do_quick_cmd(SMBusDevice *dev, int recv)
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{
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SMBusDeviceInfo *t = container_of(dev->i2c.info, SMBusDeviceInfo, i2c);
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DPRINTF("Quick Command %d\n", recv);
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if (t->quick_cmd)
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t->quick_cmd(dev, recv);
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}
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static void smbus_do_write(SMBusDevice *dev)
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{
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SMBusDeviceInfo *t = container_of(dev->i2c.info, SMBusDeviceInfo, i2c);
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if (dev->data_len == 0) {
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smbus_do_quick_cmd(dev, 0);
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} else if (dev->data_len == 1) {
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DPRINTF("Send Byte\n");
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if (t->send_byte) {
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t->send_byte(dev, dev->data_buf[0]);
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}
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} else {
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dev->command = dev->data_buf[0];
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DPRINTF("Command %d len %d\n", dev->command, dev->data_len - 1);
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if (t->write_data) {
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t->write_data(dev, dev->command, dev->data_buf + 1,
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dev->data_len - 1);
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}
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}
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}
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static void smbus_i2c_event(i2c_slave *s, enum i2c_event event)
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{
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SMBusDevice *dev = FROM_I2C_SLAVE(SMBusDevice, s);
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switch (event) {
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case I2C_START_SEND:
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switch (dev->mode) {
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case SMBUS_IDLE:
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DPRINTF("Incoming data\n");
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dev->mode = SMBUS_WRITE_DATA;
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break;
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default:
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BADF("Unexpected send start condition in state %d\n", dev->mode);
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dev->mode = SMBUS_CONFUSED;
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break;
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}
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break;
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case I2C_START_RECV:
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switch (dev->mode) {
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case SMBUS_IDLE:
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DPRINTF("Read mode\n");
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dev->mode = SMBUS_RECV_BYTE;
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break;
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case SMBUS_WRITE_DATA:
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if (dev->data_len == 0) {
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BADF("Read after write with no data\n");
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dev->mode = SMBUS_CONFUSED;
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} else {
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if (dev->data_len > 1) {
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smbus_do_write(dev);
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} else {
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dev->command = dev->data_buf[0];
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DPRINTF("%02x: Command %d\n", dev->i2c.address,
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dev->command);
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}
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DPRINTF("Read mode\n");
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dev->data_len = 0;
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dev->mode = SMBUS_READ_DATA;
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}
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break;
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default:
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BADF("Unexpected recv start condition in state %d\n", dev->mode);
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dev->mode = SMBUS_CONFUSED;
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break;
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}
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break;
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case I2C_FINISH:
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switch (dev->mode) {
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case SMBUS_WRITE_DATA:
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smbus_do_write(dev);
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break;
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case SMBUS_RECV_BYTE:
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smbus_do_quick_cmd(dev, 1);
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break;
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case SMBUS_READ_DATA:
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BADF("Unexpected stop during receive\n");
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break;
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default:
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/* Nothing to do. */
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break;
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}
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dev->mode = SMBUS_IDLE;
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dev->data_len = 0;
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break;
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case I2C_NACK:
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switch (dev->mode) {
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case SMBUS_DONE:
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/* Nothing to do. */
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break;
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case SMBUS_READ_DATA:
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dev->mode = SMBUS_DONE;
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break;
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default:
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BADF("Unexpected NACK in state %d\n", dev->mode);
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dev->mode = SMBUS_CONFUSED;
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break;
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}
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}
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}
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static int smbus_i2c_recv(i2c_slave *s)
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{
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SMBusDeviceInfo *t = container_of(s->info, SMBusDeviceInfo, i2c);
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SMBusDevice *dev = FROM_I2C_SLAVE(SMBusDevice, s);
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int ret;
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switch (dev->mode) {
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case SMBUS_RECV_BYTE:
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if (t->receive_byte) {
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ret = t->receive_byte(dev);
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} else {
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ret = 0;
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}
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DPRINTF("Receive Byte %02x\n", ret);
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dev->mode = SMBUS_DONE;
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break;
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case SMBUS_READ_DATA:
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if (t->read_data) {
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ret = t->read_data(dev, dev->command, dev->data_len);
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dev->data_len++;
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} else {
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ret = 0;
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}
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DPRINTF("Read data %02x\n", ret);
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break;
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default:
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BADF("Unexpected read in state %d\n", dev->mode);
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dev->mode = SMBUS_CONFUSED;
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ret = 0;
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break;
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}
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return ret;
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}
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static int smbus_i2c_send(i2c_slave *s, uint8_t data)
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{
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SMBusDevice *dev = FROM_I2C_SLAVE(SMBusDevice, s);
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switch (dev->mode) {
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case SMBUS_WRITE_DATA:
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DPRINTF("Write data %02x\n", data);
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dev->data_buf[dev->data_len++] = data;
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break;
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default:
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BADF("Unexpected write in state %d\n", dev->mode);
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break;
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}
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return 0;
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}
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static void smbus_device_init(i2c_slave *i2c)
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{
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SMBusDeviceInfo *t = container_of(i2c->info, SMBusDeviceInfo, i2c);
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SMBusDevice *dev = FROM_I2C_SLAVE(SMBusDevice, i2c);
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t->init(dev);
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}
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void smbus_register_device(const char *name, int size, SMBusDeviceInfo *info)
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{
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assert(size >= sizeof(SMBusDevice));
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info->i2c.init = smbus_device_init;
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info->i2c.event = smbus_i2c_event;
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info->i2c.recv = smbus_i2c_recv;
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info->i2c.send = smbus_i2c_send;
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i2c_register_slave(name, size, &info->i2c);
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}
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/* Master device commands. */
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void smbus_quick_command(i2c_bus *bus, int addr, int read)
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{
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i2c_start_transfer(bus, addr, read);
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i2c_end_transfer(bus);
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}
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uint8_t smbus_receive_byte(i2c_bus *bus, int addr)
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{
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uint8_t data;
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i2c_start_transfer(bus, addr, 1);
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data = i2c_recv(bus);
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i2c_nack(bus);
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i2c_end_transfer(bus);
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return data;
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}
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void smbus_send_byte(i2c_bus *bus, int addr, uint8_t data)
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{
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, data);
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i2c_end_transfer(bus);
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}
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uint8_t smbus_read_byte(i2c_bus *bus, int addr, uint8_t command)
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{
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uint8_t data;
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command);
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i2c_start_transfer(bus, addr, 1);
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data = i2c_recv(bus);
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i2c_nack(bus);
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i2c_end_transfer(bus);
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return data;
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}
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void smbus_write_byte(i2c_bus *bus, int addr, uint8_t command, uint8_t data)
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{
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command);
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i2c_send(bus, data);
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i2c_end_transfer(bus);
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}
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uint16_t smbus_read_word(i2c_bus *bus, int addr, uint8_t command)
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{
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uint16_t data;
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command);
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i2c_start_transfer(bus, addr, 1);
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data = i2c_recv(bus);
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data |= i2c_recv(bus) << 8;
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i2c_nack(bus);
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i2c_end_transfer(bus);
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return data;
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}
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void smbus_write_word(i2c_bus *bus, int addr, uint8_t command, uint16_t data)
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{
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command);
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i2c_send(bus, data & 0xff);
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i2c_send(bus, data >> 8);
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i2c_end_transfer(bus);
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}
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int smbus_read_block(i2c_bus *bus, int addr, uint8_t command, uint8_t *data)
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{
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int len;
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int i;
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command);
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i2c_start_transfer(bus, addr, 1);
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len = i2c_recv(bus);
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if (len > 32)
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len = 0;
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for (i = 0; i < len; i++)
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data[i] = i2c_recv(bus);
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i2c_nack(bus);
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i2c_end_transfer(bus);
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return len;
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}
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void smbus_write_block(i2c_bus *bus, int addr, uint8_t command, uint8_t *data,
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int len)
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{
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int i;
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if (len > 32)
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len = 32;
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command);
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i2c_send(bus, len);
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for (i = 0; i < len; i++)
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i2c_send(bus, data[i]);
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i2c_end_transfer(bus);
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}
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