[PATCH v2] spi: rockchip: restore bus_num alias lookup via dev->id

[Stephano Cetola <stephano@cetola.net>]

ctlr->bus_num = pdev->id was commented out when this driver was
ported from Linux. pdev doesn't exist in barebox's device model here,
only dev. The port left this line unresolved instead of translating
it. With bus_num left at its kzalloc default of 0,
spi_register_controller() only runs the alias lookup when bus_num < 0,
so it's skipped and every Rockchip SPI controller ends up on bus 0.

Any board that enables two Rockchip SPI controllers at once hits this
bug. Both end up on bus 0. Looking one up by bus number can then
return the wrong controller.

Fixes: 1efba64ba04 ("spi: add rockchip spi controller support")
Signed-off-by: Stephano Cetola <stephano@cetola.net>
---
We saw this on the MNT Pocket Reform (RK3588S). spi@feb20000 returns
the PMIC controller instead of the intended gpio-spi RP2040 bus. The
barebox spi command then does a write+read through the Rockchip SPI
driver, which programmes the hardware in XFM_RO (RX-only) mode for
the read phase. In that mode dummy TXDR writes don't generate clock
pulses, the RX FIFO never fills, and rockchip_spi_pio's while(1) loop
never exits.
---
Changes in v2:
- Updated commit message for clarity.
- Link to v1: https://patch.msgid.link/20260822-send-spi-rockchip-busnum-v1-1-bf9c183786e4@cetola.net

To: Sascha Hauer <s.hauer@pengutronix.de>
To: "open list:BAREBOX" <barebox@lists.infradead.org>
---
 drivers/spi/spi-rockchip.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index 1e81e9393f..b9f43fa4d6 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -514,7 +514,7 @@ static int rockchip_spi_probe(struct device *dev)
 		goto err_put_ctlr;
 	}
 
-//	ctlr->bus_num = pdev->id;
+	ctlr->bus_num = dev->id;
 //	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_LSB_FIRST;
 
 	/*

---
base-commit: 9bc1a26592a59919d2ee8c60c273d87d3d9f2e81
change-id: 20260821-send-spi-rockchip-busnum-a9b1116e14a5