[PATCH v3 0/4] mtd: spi: spi-nor: rk3399: rock-pi-4: u-boot/next Support SPI NOR Flash in Rock Pi 4 (XTX xt25f32b)

[Xavier Drudis Ferran]

The Radxa Rock Pi 4 board is sold from revision 1.4 with a soldered
4Mb SPI NOR Flash. This series allows to use it from U-Boot and boot
from it.

This series applies to u-boot/master.

Changes since v2:

   - rebased on master
 
   - droped 5th path, and enabled CONFIG_SPL_DM_SEQ_ALIAS instead
     to have the flash on spi1 both on SPL and U-Boot proper.

Changes since v1:

   - Changed bus number to 1 in SPL to match U-Boot proper (before it
     was bus 0 in SPL and bus 1 in U-Boot).

   - Generalization. v1 did a first soft_reset in 8_8_8_DTR but that
     wouldn't work since Pratyush Yadav fixed supports_op() in commit
     5752d6ae8daacbd ("spi: spi-mem: add spi_mem_dtr_supports_op()").
     So now we try a few protocols until 1_1_1 is supported by
     controller and device. Might work for more systems.