• Jon Hunter's avatar
    mfd: as3722: Handle interrupts on suspend · 35deff7e
    Jon Hunter authored
    The as3722 device is registered as an irqchip and the as3722-rtc interrupt
    is one of it's interrupt sources. When using the as3722-rtc as a wake-up
    device from suspend, the following is seen:
    
      PM: Syncing filesystems ... done.
      Freezing user space processes ... (elapsed 0.001 seconds) done.
      Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
      Suspending console(s) (use no_console_suspend to debug)
      PM: suspend of devices complete after 161.119 msecs
      PM: late suspend of devices complete after 1.048 msecs
      PM: noirq suspend of devices complete after 0.756 msecs
      Disabling non-boot CPUs ...
      CPU1: shutdown
      CPU2: shutdown
      CPU3: shutdown
      Entering suspend state LP1
      Enabling non-boot CPUs ...
      CPU1 is up
      CPU2 is up
      CPU3 is up
      PM: noirq resume of devices complete after 0.487 msecs
      as3722 4-0040: Failed to read IRQ status: -16
      as3722 4-0040: Failed to read IRQ status: -16
      as3722 4-0040: Failed to read IRQ status: -16
      as3722 4-0040: Failed to read IRQ status: -16
      ...
    
    The reason why the as3722 interrupt status cannot be read is because the
    as3722 interrupt is not masked during suspend and when the as3722-rtc
    interrupt occurs, to wake-up the device, the interrupt is seen before the
    i2c controller has been resumed in order to read the as3722 interrupt
    status.
    
    The as3722-rtc driver sets it's interrupt as a wake-up source during
    suspend, which gets propagated to the parent as3722 interrupt. However,
    the as3722-rtc driver cannot disable it's interrupt during suspend
    otherwise we would never be woken up and so the as3722 must disable it's
    interrupt instead.
    
    Fix this by disabling the as3722 interrupt during suspend. To ensure that
    a wake-up event from the as3722 is not missing, enable the as3722 interrupt
    as a wake-up source before disabling the interrupt on entering suspend.
    Signed-off-by: default avatarJon Hunter <jonathanh@nvidia.com>
    Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
    35deff7e
as3722.c 12.7 KB