The API for PTP system timestamping (associating a SPI transaction with
the system time at which it was transferred) is flawed: it assumes that
the xfer->tx_buf pointer will always be present.
This is, of course, not always the case.
So introduce a "progress" variable that denotes how many word have been
transferred.
Fix the Freescale DSPI driver, the only user of the API so far, in the
same patch.
Fixes: b42faeee71 ("spi: Add a PTP system timestamp to the transfer structure")
Fixes: d6b71dfaee ("spi: spi-fsl-dspi: Implement the PTP system timestamping for TCFQ mode")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20191227012417.1057-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
862dd2a946