spi: Kconfig: Add help text
Add detailed help text for SPI support.
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index b8ca2bd..0152dff 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -1,5 +1,22 @@
menuconfig SPI
bool "SPI Support"
+ help
+ The "Serial Peripheral Interface" is a low level synchronous
+ protocol. Chips that support SPI can have data transfer rates
+ up to several tens of Mbit/sec. Chips are addressed with a
+ controller and a chipselect. Most SPI slaves don't support
+ dynamic device discovery; some are even write-only or read-only.
+
+ SPI is widely used by microcontrollers to talk with sensors,
+ eeprom and flash memory, codecs and various other controller
+ chips, analog to digital (and d-to-a) converters, and more.
+ MMC and SD cards can be accessed using SPI protocol; and for
+ DataFlash cards used in MMC sockets, SPI must always be used.
+
+ SPI is one of a family of similar protocols using a four wire
+ interface (select, clock, data in, data out) including Microwire
+ (half duplex), SSP, SSI, and PSP. This driver framework should
+ work with most such devices and controllers.
if SPI