Hello ,
What's issus cause i2c ack too slow as below function?
check my dts file , clock-frequency set 375000 . but receive response still slow.
[ 17.756617] [i2c-core.c][i2c_transfer], line:[2111] i2c_transfer start
[ 17.757515] i2c i2c-0: master_xfer[0] W, addr=0x68, len=1
[ 17.758213] i2c i2c-0: master_xfer[1] R, addr=0x68, len=1
[ 17.805545] [i2c-core.c][i2c_transfer], line:[2134] i2c_transfer done
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
int ret;
/* REVISIT the fault reporting model here is weak:
*
* - When we get an error after receiving N bytes from a slave,
* there is no way to report "N".
*
* - When we get a NAK after transmitting N bytes to a slave,
* there is no way to report "N" ... or to let the master
* continue executing the rest of this combined message, if
* that's the appropriate response.
*
* - When for example "num" is two and we successfully complete
* the first message but get an error part way through the
* second, it's unclear whether that should be reported as
* one (discarding status on the second message) or errno
* (discarding status on the first one).
*/
KDBG("i2c_transfer start");
if (adap->algo->master_xfer) {
//#ifdef DEBUG
for (ret = 0; ret < num; ret++) {
dev_info(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
"len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
}
//#endif
if (in_atomic() || irqs_disabled()) {
ret = i2c_trylock_adapter(adap);
if (!ret)
/* I2C activity is ongoing. */
KDBG("i2c_transfer done");
return -EAGAIN;
} else {
i2c_lock_adapter(adap);
}
ret = __i2c_transfer(adap, msgs, num);
i2c_unlock_adapter(adap);
KDBG("i2c_transfer done");
return ret;
} else {
dev_dbg(&adap->dev, "I2C level transfers not supported\n");
return -EOPNOTSUPP;
}
}
Thanks,
Ben
