• Doug Anderson's avatar
    charger: tps65090: Allow charger module to be used when no irq · 193dcced
    Doug Anderson authored
    On the ARM Chromebook tps65090 has two masters: the AP (the main
    processor running linux) and the EC (the embedded controller).  The AP
    is allowed to mess with FETs but the EC is in charge of charge control.
    
    The tps65090 interupt line is routed to both the AP and the EC, which
    can cause quite a headache.  Having two people adjusting masks and
    acking interrupts is a recipe for disaster.
    
    In the shipping kernel we had a hack to have the AP pay attention to
    the IRQ but not to ack it.  It also wasn't supposed to configure the
    IRQ in any way.  That hack allowed us to detect when the device was
    charging without messing with the EC's state.
    
    The current tps65090 infrastructure makes the above difficult, and it
    was a bit of a hack to begin with.  Rather than uglify the driver to
    support it, just extend the driver's existing notion of "no irq" to
    the charger.  This makes the charger code poll every 2 seconds for AC
    detect, which is sufficient.
    
    For proper functioning, requires (mfd: tps65090: Don't tell child
    devices we have an IRQ if we don't).  If we don't have that patch
    we'll simply fail to probe on devices without an interrupt (just like
    we did before this patch).
    Signed-off-by: default avatarDoug Anderson <dianders@chromium.org>
    Reviewed-by: default avatarJavier Martinez Canillas <javier.martinez@collabora.co.uk>
    Tested-by: default avatarJavier Martinez Canillas <javier.martinez@collabora.co.uk>
    [sre@kernel.org: Use -ENXIO instead of NO_IRQ for missing interrupt,
    since NO_IRQ is not available on all architectures.]
    Signed-off-by: default avatarSebastian Reichel <sre@kernel.org>
    193dcced
tps65090-charger.c 8.93 KB