530edb501c
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 Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com> Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> |
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.