#2733 assigned defect

raspberrypi: SPI driver has several flaws

Reported by: Jan Sommer Owned by: Needs Funding
Priority: normal Milestone: Indefinite
Component: unspecified Version: 5
Severity: normal Keywords: spi raspberrypi driver
Cc: Blocked By:
Blocking:

Description

I started to work with the SPI of the raspberry pi and noticed several problems with the current driver after recording the frames with a logic analyzer:

  • Setting the chip select signal using the CSPOL-bits of the control register creates incorrect chip select signals
  • After every byte written to the TX FIFO buffer the driver waits for a signal from an interrupt. This creates very long pauses between consecutive bytes.
  • The lsb-first mode does not look as if it would work
  • 3-wire/bidirectional mode might not work
  • Accessing the driver from a different thread than the one which called spi_init will cause a deadlock
  • Simultaneous read-write-operation is not supported

I will submit a patchset for this after some testing.

Change History (1)

comment:1 Changed on Feb 15, 2017 at 2:20:42 PM by Sebastian Huber

Milestone: 4.12Indefinite
Owner: set to Needs Funding
Status: newassigned
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