[U-Boot] [PATCH] README: SPI: Add & explain missed SPI & serial flash options.

[Ahmed Samir Khalil]

There are no README documentation about these options of SPI &
serial flash devices. Documenting these options makes getting
startup, configuration & testing easier.

Signed-off-by: Ahmed Samir Khalil <engkhalil86 at gmail.com>
---
 README | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/README b/README
index 1d0b946..9cf3a05 100644
--- a/README
+++ b/README
@@ -2689,6 +2689,21 @@ CBFS (Coreboot Filesystem) support
 		Timeout for waiting until spi transfer completed.
 		default: (CONFIG_SYS_HZ/100)     /* 10 ms */
 
+		CONFIG_SPI_FLASH
+		Include SPI flash core, interface, and parameters table,
+		and serial flash probing.
+
+		CONFIG_SPI_FLASH_MTD
+		Register SPI flash to the MTD subsystem. Needed for MTD operations.
+
+		CONFIG_SYS_SPI_U_BOOT_OFFS
+		Location in SPI to read U-Boot from.
+
+		CONFIG_DM_SPI, CONFIG_DM_SPI_FLASH
+		Use the Driver Model (DM) for SPI devices, and SPI flash.
+		For more details on how to port legacy driver to the new DM,
+		see doc/driver-model/spi-howto.txt
+
 - FPGA Support: CONFIG_FPGA
 
 		Enables FPGA subsystem.
-- 
2.7.4