On Mon, Apr 13, 2015 at 12:59:30PM +0200, Michael Grzeschik wrote: > The current implementation of bitbang_txrx_be_cpha0 and > bitbang_txrx_be_cpha1 always call setmosi. That runs into several > unnecessary calls into the gpiolib when the level of the GPIO actually > has not to be changed. > > This patch changes the routines to remember the last GPIO level > and only calls setmosi if an change has to be made. This > way it improves the transfer throughput. Do you have any benchmarking or anything showing that this offers a practical benefit? Generally a bitbanging system would be using memory mapped GPIOs for the bus so we're talking about replacing a memory access with some shifts and logic operations here and while I can believe that something that runs in cache is going to be an overall win over going out to a device it's not quite so clear cut as it could be.
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