tree 0b7ae226269634ac2f4d572d44bb39617942fde0
parent 3b95c03d5706255f39a8f1a0fa02045d4fd981df
author Quentin Schulz <quentin.schulz@theobroma-systems.com> 1710408974 +0100
committer Kever Yang <kever.yang@rock-chips.com> 1710411584 +0800

rockchip: spi: rk_spi: do not write bytes when in read-only mode

The read-only mode is currently supported but only for 16b-aligned
buffers. For unaligned buffers, the last byte will be read in RW mode
right now, which isn't what is desired. Instead, let's put the
controller back into RO mode for that last byte and skip any write in
the xfer loop.

This is required for 3-wire SPI mode where PICO/POCI lanes are shorted
on HW level. This incidentally the recommended design for RK806 PMIC for
RK3588 products.

Cc: Quentin Schulz <foss+uboot@0leil.net>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>