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The existing driver erroneously treats I2C_BLOCK_DATA and BLOCK_DATA commands the same. For I2C_BLOCK_DATA reads, the length of the read is provided in data->block[0], but the length itself should not be sent to the slave. In contrast, for BLOCK_DATA reads no length is specified since the length will be the first byte returned from the slave. When copying data back to the data buffer, for an I2C_BLOCK_DATA read we have to take care not to overwrite data->block[0] to avoid overwriting the length. A BLOCK_DATA read doesn't have this concern since the first byte returned by the device is the length and belongs in data->block[0]. For I2C_BLOCK_DATA writes, the length is also provided in data->block[0], but the length itself is not sent to the slave (in contrast to BLOCK_DATA writes where the length prefixes the data sent to the slave). This was tested on physical hardware using i2cdump with the i and s flags to test the behavior of I2C_BLOCK_DATA reads and BLOCK_DATA reads, respectively. Writes were not tested but the I2C_BLOCK_DATA write change is pretty simple to verify by inspection. Signed-off-by: Eudean Sun <eudean@arista.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.