• Ian Abbott's avatar
    staging: comedi: amplc_pci230: simplify interrupt enable handling · d8b0e423
    Ian Abbott authored
    `struct pci230_private` has two members to manage the enabled interrupt
    sources.  `int_en` is the interrupt sources we want to be enabled and
    `ier` is a shadow of the write-only interrupt enable register.  They
    have the same value most of the time.  They differ in the interrupt
    handler (`pci230_interrupt()`) itself when it temporarily clears bits in
    the interrupt enable register and the `ier` member in order to unlatch
    them in hardware, but leaves the `int_en` member alone.  They also
    differ in `pci230_ai_stop()` and `pci230_ao_stop()` which clear bits in
    the `int_en` member and wait for the interrupt handler to finish before
    copying the value to the `ier` member and the interrupt enable register.
    
    Simplify the handling a bit, by making the `ier` member take on the role
    of the `int_en` member, and allowing the value to differ from the
    interrupt enable register while the interrupt handler is running.
    Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
    Reviewed-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    d8b0e423
amplc_pci230.c 79.5 KB