Hello Wolfram, On 03/04/2019 22:54, Wolfram Sang wrote: >> Some recent commits to this driver were trying to make sure the TSS >> interrupt is not generated on busy system due to 25ms timer expiring >> between commands. It can still happen, however if STOP command is not >> issued on time at the end of the transmission. If wait_for_completion in >> axxia_i2c_xfer_msg() would not return after 25ms of getting an >> interrupt, TSS will be generated and idev->err_msg will be set to >> -ETIMEDOUT which will be returned from the axxia_i2c_xfer_msg(), even >> though the transfer did actually succeed (STOP is automatically issued >> when TSS triggers). >> >> Fortunately, apart from already used manual and sequence commands, the >> controller also has so called auto command. It works just like manual >> mode but it but an automatic STOP is issued when either transfer length >> is met or NAK is received from slave device. >> >> This patch changes the axxia_i2c_xfer_msg() function so that auto >> command is used for last message in transaction letting hardware manage >> issuing STOP. TSS is disabled just after command transferring last >> message finishes. Auto command, just like sequence, ends with SS >> interrupt instead of SNS so handling of both had to be unified. >> >> The axxia_i2c_stop() is no longer needed as the transfer can only end >> with following conditions: >> - fully successful - then last message was send by AUTO command and STOP >> was issued automatically >> - NAK received - STOP is issued automatically by controller >> - arbitration lost - STOP should not be issued as we don't control the >> bus >> - IP interrupt received - this is sent when transfer length is set to 0 >> for auto/sequence command. The check for that is done before START is >> send so no STOP is required >> - TSS received between commands - STOP is issued by the controller > I am not sure. Is this a bugfix (= for-current) or more a new feature (= > for-next)? > >> Signed-off-by: Krzysztof Adamski <krzysztof.adamski@xxxxxxxxx> >> Reviewed-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx> > I trust you that Alexander gave the review, but it would be a tad more > 'open development' if he could give it as a reply to your patch on the > mailing list. sure, here it is: Reviewed-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx> -- Best regards, Alexander Sverdlin.
