On Fri, Mar 22, 2013 at 12:29 AM, Rajeshwari Shinde rajeshwari.s@samsung.com wrote:
A SPI slave may take time to react to a request. For SPI flash devices this time is defined as one bit time, or a whole byte for 'fast read' mode.
If the SPI slave is another CPU, then the time it takes to react may vary. It is convenient to allow the slave device to tag the start of the actual reply so that the host can determine when this 'preamble' finishes and the actual message starts.
Add a preamble flag to the available SPI flags. If supported by the driver then it will ignore any received bytes before the preamble on each transaction. This ensures that reliable communication with the slave is possible.
Signed-off-by: Simon Glass sjg@chromium.org Signed-off-by: Rajeshwari Shinde rajeshwari.s@samsung.com
Acked-by: Simon Glass sjg@chromium.org