| Message ID | 20240830034640.7049-6-kfting@nuvoton.com |
|---|---|
| State | New |
| Headers | show |
| Series | i2c: npcm: Bug fixes read/write operation, checkpatch | expand |
On Fri, Aug 30, 2024 at 11:46:38AM +0800, Tyrone Ting wrote: > Store the client address earlier since it's used in the i2c_recover_bus > logic flow. Here no explanation why it's now left-shifted by one bit.
Hi Andy: Thank you for your comments. Andy Shevchenko <andriy.shevchenko@linux.intel.com> 於 2024年8月31日 週六 上午3:16寫道： > > On Fri, Aug 30, 2024 at 11:46:38AM +0800, Tyrone Ting wrote: > > Store the client address earlier since it's used in the i2c_recover_bus > > logic flow. > > Here no explanation why it's now left-shifted by one bit. The address is stored from bit 1 to bit 7 in the register for sending the i2c address later. I'll write some comments about the left-shifted by one bit behavior above this modification in next patch set. > > -- > With Best Regards, > Andy Shevchenko > > Thank you. Regards, Tyrone
On Mon, Sep 02, 2024 at 09:40:09AM +0800, Tyrone Ting wrote: > Andy Shevchenko <andriy.shevchenko@linux.intel.com> 於 2024年8月31日 週六 上午3:16寫道： > > On Fri, Aug 30, 2024 at 11:46:38AM +0800, Tyrone Ting wrote: > > > Store the client address earlier since it's used in the i2c_recover_bus > > > logic flow. > > > > Here no explanation why it's now left-shifted by one bit. > > The address is stored from bit 1 to bit 7 in the register for sending > the i2c address later. Yes, but previously it was stored w/o that shift. > I'll write some comments about the left-shifted by one bit behavior > above this modification in next patch set.
Hi Andy: Thank you for your feedback. Andy Shevchenko <andriy.shevchenko@linux.intel.com> 於 2024年9月2日 週一 下午7:54寫道： > > On Mon, Sep 02, 2024 at 09:40:09AM +0800, Tyrone Ting wrote: > > Andy Shevchenko <andriy.shevchenko@linux.intel.com> 於 2024年8月31日 週六 上午3:16寫道： > > > On Fri, Aug 30, 2024 at 11:46:38AM +0800, Tyrone Ting wrote: > > > > Store the client address earlier since it's used in the i2c_recover_bus > > > > logic flow. > > > > > > Here no explanation why it's now left-shifted by one bit. > > > > The address is stored from bit 1 to bit 7 in the register for sending > > the i2c address later. > > Yes, but previously it was stored w/o that shift. > Previously, the address was stored w/o that shift and with that shift in the following call to npcm_i2c_master_start_xmit, just like what https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-npcm7xx.c#L2043 shows. Since there are cases that the i2c_recover_bus gets called at the early stage of the function npcm_i2c_master_xfer, the address is stored with the shift and used in the i2c_recover_bus call. > > I'll write some comments about the left-shifted by one bit behavior > > above this modification in next patch set. > > -- > With Best Regards, > Andy Shevchenko > > Thank you. Regards, Tyrone
diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c index 68f3d47323ab..67d156ed29b9 100644 --- a/drivers/i2c/busses/i2c-npcm7xx.c +++ b/drivers/i2c/busses/i2c-npcm7xx.c @@ -2155,6 +2155,7 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, } while (time_is_after_jiffies(time_left) && bus_busy); + bus->dest_addr = slave_addr << 1; if (bus_busy || bus->ber_state) { iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST); npcm_i2c_reset(bus); @@ -2163,7 +2164,6 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, } npcm_i2c_init_params(bus); - bus->dest_addr = slave_addr; bus->msgs = msgs; bus->msgs_num = num; bus->cmd_err = 0;
Store the client address earlier since it's used in the i2c_recover_bus logic flow. Fixes: 48acf8292280 ("i2c: Remove redundant comparison in npcm_i2c_reg_slave") Signed-off-by: Tyrone Ting <kfting@nuvoton.com> --- drivers/i2c/busses/i2c-npcm7xx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)