Re: [PATCH v5] fpga: xilinx-selectmap: control CSI_B and RDWR_B during configuration

[Xu Yilun]

On Wed, Sep 09, 2026 at 01:21:54PM +0200, Heiko Schocher wrote:
> The driver requests the optional CSI_B and RDWR_B GPIOs with
> GPIOD_OUT_HIGH and never touches them again. That flag carries a
> logical value, so both signals end up asserted from probe on, whatever
> polarity the device tree states, and they stay asserted for the
> lifetime of the device.
> 
> Neither signal belongs to the driver's lifetime. CSI_B (Chip Select)
> selects the device on the SelectMAP port, RDWR_B (Read/Write) selects
> the transfer direction, so both belong to the data transfer. A device
> that is never deselected never lets go of the port, and a port pinned
> to write mode cannot be read back.
> 
> Keep the two descriptors in the driver private data, request them
> deasserted, and assert them only around the configuration data
> transfer. RDWR_B is asserted first, UG470 describes in chapter
> "SelectMAP ABORT" that changing it while the device is selected aborts
> the configuration on the next CCLK.
> 
> Signed-off-by: Heiko Schocher <hs@xxxxxxxxxxxx>

Reviewed-by: Xu Yilun <yilun.xu@xxxxxxxxx>

Applied to for-next.