spi-rx-bus-width 0 not supported in boot logs

[rus084]

I read boot log from https://t.me/zhovner_hub/2253
and found warning message "spi-rx-bus-width 0 not supported"

This happenes because in dts file spi-rx-bus-width set is not correct for display here:

u-boot/dts/upstream/src/arm64/rockchip/rk3576-flipper-one-rev-f0b0c1.dts

Line 1530 in 11b81e3

spi-rx-bus-width = <0>;

and log prints here

u-boot/drivers/spi/spi-uclass.c

Line 262 in 11b81e3

warn_non_xpl("spi-rx-bus-width %d not supported\n", value);

[alchark]

This happenes because in dts file spi-rx-bus-width set is not correct for display

It is correct in the device tree, but U-boot doesn’t currently explicitly support this mode of operation. It still works though.

The rx line (MISO in SPI terms) is physically unconnected on the display bus, as its pin is reused as the GPIO to signal end of frame.

Patches to add explicit support for no-RX operation are welcome (directly to upstream U-boot ideally), though it’s not super high priority as it doesn’t have any functional effect apart from this warning