Message ID | 20240920101820.44850-4-kfting@nuvoton.com |
---|---|
State | New |
Headers | show |
Series | i2c: npcm: read/write operation, checkpatch | expand |
Hi Tyrone, ... > diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c > index 2d034503d8bc..68f3d47323ab 100644 > --- a/drivers/i2c/busses/i2c-npcm7xx.c > +++ b/drivers/i2c/busses/i2c-npcm7xx.c > @@ -2132,19 +2132,12 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > } > } > > - /* > - * Adaptive TimeOut: estimated time in usec + 100% margin: > - * 2: double the timeout for clock stretching case > - * 9: bits per transaction (including the ack/nack) > - */ > - timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite); > - timeout = max_t(unsigned long, bus->adap.timeout, usecs_to_jiffies(timeout_usec)); > if (nwrite >= 32 * 1024 || nread >= 32 * 1024) { > dev_err(bus->dev, "i2c%d buffer too big\n", bus->num); > return -EINVAL; > } > > - time_left = jiffies + timeout + 1; > + time_left = jiffies + bus->adap.timeout / bus->adap.retries + 1; > do { > /* > * we must clear slave address immediately when the bus is not > @@ -2183,6 +2176,14 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > if (npcm_i2c_master_start_xmit(bus, slave_addr, nwrite, nread, > write_data, read_data, read_PEC, > read_block)) { > + /* > + * Adaptive TimeOut: estimated time in usec + 100% margin: > + * 2: double the timeout for clock stretching case > + * 9: bits per transaction (including the ack/nack) > + */ > + timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite); > + timeout = max_t(unsigned long, bus->adap.timeout / bus->adap.retries, > + usecs_to_jiffies(timeout_usec)); > time_left = wait_for_completion_timeout(&bus->cmd_complete, > timeout); > > @@ -2308,7 +2309,7 @@ static int npcm_i2c_probe_bus(struct platform_device *pdev) > adap = &bus->adap; > adap->owner = THIS_MODULE; > adap->retries = 3; > - adap->timeout = msecs_to_jiffies(35); > + adap->timeout = 2 * HZ; Same here, I need some good description of why timeout is set to 2 seconds. If the datasheet says 35ms, I do not exclude that someone in the future will send a patch saying "we don't need to wait 2 seconds, wait 35ms as per datasheet". Thanks, Andi > adap->algo = &npcm_i2c_algo; > adap->quirks = &npcm_i2c_quirks; > adap->algo_data = bus; > -- > 2.34.1 >
Hi Andi: Thank you for your feedback. Your comments will be addressed. Andi Shyti <andi.shyti@kernel.org> 於 2024年9月26日 週四 上午4:24寫道: > > Hi Tyrone, > > ... > > > diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c > > index 2d034503d8bc..68f3d47323ab 100644 > > --- a/drivers/i2c/busses/i2c-npcm7xx.c > > +++ b/drivers/i2c/busses/i2c-npcm7xx.c > > @@ -2132,19 +2132,12 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > } > > } > > > > - /* > > - * Adaptive TimeOut: estimated time in usec + 100% margin: > > - * 2: double the timeout for clock stretching case > > - * 9: bits per transaction (including the ack/nack) > > - */ > > - timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite); > > - timeout = max_t(unsigned long, bus->adap.timeout, usecs_to_jiffies(timeout_usec)); > > if (nwrite >= 32 * 1024 || nread >= 32 * 1024) { > > dev_err(bus->dev, "i2c%d buffer too big\n", bus->num); > > return -EINVAL; > > } > > > > - time_left = jiffies + timeout + 1; > > + time_left = jiffies + bus->adap.timeout / bus->adap.retries + 1; > > do { > > /* > > * we must clear slave address immediately when the bus is not > > @@ -2183,6 +2176,14 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > if (npcm_i2c_master_start_xmit(bus, slave_addr, nwrite, nread, > > write_data, read_data, read_PEC, > > read_block)) { > > + /* > > + * Adaptive TimeOut: estimated time in usec + 100% margin: > > + * 2: double the timeout for clock stretching case > > + * 9: bits per transaction (including the ack/nack) > > + */ > > + timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite); > > + timeout = max_t(unsigned long, bus->adap.timeout / bus->adap.retries, > > + usecs_to_jiffies(timeout_usec)); > > time_left = wait_for_completion_timeout(&bus->cmd_complete, > > timeout); > > > > @@ -2308,7 +2309,7 @@ static int npcm_i2c_probe_bus(struct platform_device *pdev) > > adap = &bus->adap; > > adap->owner = THIS_MODULE; > > adap->retries = 3; > > - adap->timeout = msecs_to_jiffies(35); > > + adap->timeout = 2 * HZ; > > Same here, I need some good description of why timeout is set to > 2 seconds. If the datasheet says 35ms, I do not exclude that > someone in the future will send a patch saying "we don't need to > wait 2 seconds, wait 35ms as per datasheet". > > Thanks, > Andi > > > adap->algo = &npcm_i2c_algo; > > adap->quirks = &npcm_i2c_quirks; > > adap->algo_data = bus; > > -- > > 2.34.1 > > Have a nice day. Regards, Tyrone
diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c index 2d034503d8bc..68f3d47323ab 100644 --- a/drivers/i2c/busses/i2c-npcm7xx.c +++ b/drivers/i2c/busses/i2c-npcm7xx.c @@ -2132,19 +2132,12 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, } } - /* - * Adaptive TimeOut: estimated time in usec + 100% margin: - * 2: double the timeout for clock stretching case - * 9: bits per transaction (including the ack/nack) - */ - timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite); - timeout = max_t(unsigned long, bus->adap.timeout, usecs_to_jiffies(timeout_usec)); if (nwrite >= 32 * 1024 || nread >= 32 * 1024) { dev_err(bus->dev, "i2c%d buffer too big\n", bus->num); return -EINVAL; } - time_left = jiffies + timeout + 1; + time_left = jiffies + bus->adap.timeout / bus->adap.retries + 1; do { /* * we must clear slave address immediately when the bus is not @@ -2183,6 +2176,14 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, if (npcm_i2c_master_start_xmit(bus, slave_addr, nwrite, nread, write_data, read_data, read_PEC, read_block)) { + /* + * Adaptive TimeOut: estimated time in usec + 100% margin: + * 2: double the timeout for clock stretching case + * 9: bits per transaction (including the ack/nack) + */ + timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite); + timeout = max_t(unsigned long, bus->adap.timeout / bus->adap.retries, + usecs_to_jiffies(timeout_usec)); time_left = wait_for_completion_timeout(&bus->cmd_complete, timeout); @@ -2308,7 +2309,7 @@ static int npcm_i2c_probe_bus(struct platform_device *pdev) adap = &bus->adap; adap->owner = THIS_MODULE; adap->retries = 3; - adap->timeout = msecs_to_jiffies(35); + adap->timeout = 2 * HZ; adap->algo = &npcm_i2c_algo; adap->quirks = &npcm_i2c_quirks; adap->algo_data = bus;