• Rob Herring's avatar
    spi: bcm2835aux: ensure interrupts are enabled for shared handler · bc519d95
    Rob Herring authored
    The BCM2835 AUX SPI has a shared interrupt line (with AUX UART).
    Downstream fixes this with an AUX irqchip to demux the IRQ sources and a
    DT change which breaks compatibility with older kernels. The AUX irqchip
    was already rejected for upstream[1] and the DT change would break
    working systems if the DTB is updated to a newer one. The latter issue
    was brought to my attention by Alex Graf.
    
    The root cause however is a bug in the shared handler. Shared handlers
    must check that interrupts are actually enabled before servicing the
    interrupt. Add a check that the TXEMPTY or IDLE interrupts are enabled.
    
    [1] https://patchwork.kernel.org/patch/9781221/
    
    Cc: Alexander Graf <agraf@suse.de>
    Cc: Marc Zyngier <marc.zyngier@arm.com>
    Cc: Mark Brown <broonie@kernel.org>
    Cc: Eric Anholt <eric@anholt.net>
    Cc: Stefan Wahren <stefan.wahren@i2se.com>
    Cc: Florian Fainelli <f.fainelli@gmail.com>
    Cc: Ray Jui <rjui@broadcom.com>
    Cc: Scott Branden <sbranden@broadcom.com>
    Cc: bcm-kernel-feedback-list@broadcom.com
    Cc: linux-spi@vger.kernel.org
    Cc: linux-rpi-kernel@lists.infradead.org
    Cc: linux-arm-kernel@lists.infradead.org
    Signed-off-by: default avatarRob Herring <robh@kernel.org>
    Reviewed-by: default avatarEric Anholt <eric@anholt.net>
    Signed-off-by: default avatarMark Brown <broonie@kernel.org>
    bc519d95
spi-bcm2835aux.c 15 KB