[En-Nut-Discussion] SPI and polling transfer

[Uwe Bonnes]

Hello,

bringing up SPI on some new device, probably always polling transfer is
implemented first. So did the STM32 SPI driver. However, is there any reason
to keep polling transfer in a mature driver? At present the STM32 provides
a choice polling transfer, IRQ transfer with an event every byte transferred
and block DMA transfer with only one event at the end of the tranferred block.

For STM32 an SPI interrupt entry is always available. So there is no
incentive to "keep polling transfer as otherwise precious resources are
occupied".

Any other reasons?

B.t.w: "SPIBUSx_POLLING_MODE" is found in the configurator for nearly all
archs...

-- 
Uwe Bonnes                bon at elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
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