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[0/3] Intel SPI unbind fixes

Message ID cover.1590408496.git.lukas@wunner.de
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Series Intel SPI unbind fixes | expand

Message

Lukas Wunner May 25, 2020, 12:25 p.m. UTC 
Fix unbind ordering issues in the Designware and PXA2xx SPI controllers
built into Intel SoCs.

To test, you'll also need the following commit:
https://git.kernel.org/broonie/spi/c/84855678add8

This is compile-tested only, so please review and test thoroughly.

Pay particular attention to the IRQ handlers dw_spi_irq() and ssp_int():
Both drivers request the interrupt with IRQF_SHARED, so the IRQ handler
may run even though the SPI controller itself hasn't signalled an
interrupt.  The IRQ is requested before registering the controller and
freed after unregistering the controller.  Thus, the IRQ handler should
immediately bail out if the controller is not yet or no longer registered,
e.g. by checking in the controller's registers whether an interrupt is
actually pending.  The drivers may need to disable interrupts in the
controllers' registers upon unbinding and they need to make sure that
the registers are accessible until the IRQ is freed.

I don't have a datasheet for these SPI controllers but I hope someone
who is more familiar with them will be able to check for correctness
of the IRQ handling.

Lukas Wunner (3):
  spi: dw: Fix controller unregister order
  spi: pxa2xx: Fix controller unregister order
  spi: pxa2xx: Fix runtime PM ref imbalance on probe error

 drivers/spi/spi-dw.c     | 4 +++-
 drivers/spi/spi-pxa2xx.c | 5 +++--
 2 files changed, 6 insertions(+), 3 deletions(-)