spi: amlogic: spisg: Fix the incorrect keep_ss of the last descriptor

The driver currently unconditionally clears CFG_KEEP_SS on the last
descriptor, causing the last transfer's cs_change setting to be ignored.

Record the cs_change value of the last SPI transfer and use it to
program CFG_KEEP_SS on the final descriptor. When a null descriptor is
inserted to implement the cs-hold delay, keep CFG_KEEP_SS set on the
preceding transfer descriptor and apply the recorded value to the final
descriptor instead.

This ensures the controller handles chip select correctly for the last
transfer regardless of whether a cs-hold delay is required.

Fixes: cef9991e04ae ("spi: Add Amlogic SPISG driver")
Signed-off-by: Sunny Luo <sunny.luo@amlogic.com>
Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
Link: https://patch.msgid.link/20260731-a9-spisg-v3-3-a15da3f70029@amlogic.com
Signed-off-by: Mark Brown <broonie@kernel.org>

0 files changed, 0 insertions, 0 deletions