Hi, I am sorry for not replying to questions in time, when I left the office early on Friday. I sincerely apologize to you again. -----邮件原件----- 发件人: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> 发送时间: 2024年9月6日 19:48 收件人: Liu Kimriver/刘金河 <kimriver.liu@xxxxxxxxxxxx> 抄送: jarkko.nikula@xxxxxxxxxxxxxxx; mika.westerberg@xxxxxxxxxxxxxxx; jsd@xxxxxxxxxxxx; andi.shyti@xxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx 主题: Re: [PATCH] i2c: designware: fix master is holding SCL low while ENABLE bit is disabled On Fri, Sep 06, 2024 at 01:42:50PM +0800, Kimriver Liu wrote: > It was observed issuing ABORT bit(IC_ENABLE[1]) will not work when > IC_ENABLE is already disabled. > > Check if ENABLE bit(IC_ENABLE[0]) is disabled when the master is > holding SCL low. If ENABLE bit is disabled, the software need enable > it before trying to issue ABORT bit. otherwise, the controller ignores > any write to ABORT bit > > Signed-off-by: Kimriver Liu <kimriver.liu@xxxxxxxxxxxx> > > --- > V3->V4: >Nice, but the Subject (which is most important part) still has no versioning :-( Thanks or your guidance. ON Monday , I will update the Subject versioning and resend V7 patch: [PATCH V7] i2c: designware: fix master is holding SCL low while ENABLE bit is disabled > 1. update commit messages and add patch version and changelog > 2. move print the error message in i2c_dw_xfer > V2->V3: change (!enable) to (!(enable & DW_IC_ENABLE_ENABLE)) > V1->V2: used standard words in function names and addressed review > V1->comments ... > + /* > + * Wait two ic_clk delay when enabling the i2c to ensure ENABLE bit > + * is already set by the driver (for 400KHz this is 25us) > + * as described in the DesignWare I2C databook. > + */ > + fsleep(25); >And if we use 100kHz? >Please, calculate this delay based on the actual speed in use (or about to be in use). Yes, I will change fsleep(25) to usleep_range(25, 250), for next V7 version. Wait 10 times the signaling period of the highest I2C transfer supported by the driver (for 400KHz this is* 25us) > + } --------------- Kimriver Liu
