PINE64 Rock64 - How to get SPI driver working

[Johannes Krottmayer]

Hello,

I just compiled U-Boot v2020.04 for a PINE64 Rock media board.
It compiles fine without errors, but when I try to probe the
on board flash I get an error:

=> sf probe
Invalid bus 0 (err=-19)
Failed to initialize SPI flash at 0:0 (error -19)
=>

SPI is activated in the Device-Tree blob. I also added support
to the Rockchip SPI driver (added IDS strings for this SoC).

In the device config I added the following:

CONFIG_SPI=y
CONFIG_ROCKCHIP_SPI=y
CONFIG_SPI_FLASH=y

But the driver still doesn't work. Output of DM (shortened):

=> dm tree
[...]
  spi           0  [   ]   rockchip_spi          |-- spi at ff190000

  spi_flash     0  [   ]   spi_flash_std         |   `-- spiflash at 0
[...]

What is missing? Is there a way to load driver?

Any kind of help is highly appreciated.

-- 
Kind regards,

Johannes K.