/**
* cdns_i2c_master_xfer - The main i2c transfer function
* @adap: pointer to the i2c adapter driver instance
* @msgs: pointer to the i2c message structure
* @num: the number of messages to transfer
*
* Initiates the send/recv activity based on the transfer message received.
*
* Return: number of msgs processed on success, negative error otherwise
*/
static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
int ret, count;
u32 reg;
struct cdns_i2c *id = adap->algo_data;
/* Check if the bus is free */
if (msgs->len)
if (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & CDNS_I2C_SR_BA)
return -EAGAIN;
/*
* Set the flag to one when multiple messages are to be
* processed with a repeated start.
*/
if (num > 1) {
/*
* This controller does not give completion interrupt after a
* master receive message if HOLD bit is set (repeated start),
* resulting in SW timeout. Hence, if a receive message is
* followed by any other message, an error is returned
* indicating that this sequence is not supported.
*/
for (count = 0; count < num - 1; count++) {
if (msgs[count].flags & I2C_M_RD) {
dev_warn(adap->dev.parent,
"Can't do repeated start after a receive message\n");
return -EOPNOTSUPP;
}
}
id->bus_hold_flag = 1;
reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
reg |= CDNS_I2C_CR_HOLD;
cdns_i2c_writereg(reg, CDNS_I2C_CR_OFFSET);
} else {
id->bus_hold_flag = 0;
}
/* Process the msg one by one */
for (count = 0; count < num; count++, msgs++) {
if (count == (num - 1))
id->bus_hold_flag = 0;
ret = cdns_i2c_process_msg(id, msgs, adap);
if (ret)
return ret;
/* Report the other error interrupts to application */
if (id->err_status) {
cdns_i2c_master_reset(adap);
if (id->err_status & CDNS_I2C_IXR_NACK)
return -ENXIO;
return -EIO;
}
}
return num;
}
/**
* cdns_i2c_master_xfer - The main i2c transfer function
* @adap: pointer to the i2c adapter driver instance
* @msgs: pointer to the i2c message structure
* @num: the number of messages to transfer
*
* Initiates the send/recv activity based on the transfer message received.
*
* Return: number of msgs processed on success, negative error otherwise
*/
static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
int ret, count;
u32 reg;
struct cdns_i2c *id = adap->algo_data;
/* Check if the bus is free */
if (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & CDNS_I2C_SR_BA)
return -EAGAIN;
/*
* Set the flag to one when multiple messages are to be
* processed with a repeated start.
*/
if (num > 1) {
id->bus_hold_flag = 1;
reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
reg |= CDNS_I2C_CR_HOLD;
cdns_i2c_writereg(reg, CDNS_I2C_CR_OFFSET);
} else {
id->bus_hold_flag = 0;
}
/* Process the msg one by one */
for (count = 0; count < num; count++, msgs++) {
if (count == (num - 1))
id->bus_hold_flag = 0;
ret = cdns_i2c_process_msg(id, msgs, adap);
if (ret)
return ret;
/* Report the other error interrupts to application */
if (id->err_status) {
cdns_i2c_master_reset(adap);
if (id->err_status & CDNS_I2C_IXR_NACK)
return -ENXIO;
return -EIO;
}
}
return num;
}
