• Dirk Behme's avatar
    Input: zforce - make the interrupt GPIO optional · 62f46669
    Dirk Behme authored
    Add support for hardware which uses an I2C Serializer / Deserializer
    (SerDes) to communicate with the zFroce touch driver. In this case the
    SerDes will be configured as an interrupt controller and the zForce driver
    will have no access to poll the GPIO line.
    
    To support this, we add two dedicated new GPIOs in the device tree:
    reset-gpios and irq-gpios, with the irq-gpios being optional.
    
    To not break the existing device trees, the index based 'gpios' entries
    are still supported, but marked as deprecated.
    
    With this, if the interrupt GPIO is available, either via the old or new
    device tree style, the while loop will read and handle the packets as long
    as the GPIO indicates that the interrupt is asserted (existing, unchanged
    driver behavior).
    
    If the interrupt GPIO isn't available, i.e. not configured via the new
    device tree style, we are falling back to one read per ISR invocation
    (new behavior to support the SerDes).
    
    Note that the gpiod functions help to handle the optional GPIO:
    devm_gpiod_get_index_optional() will return NULL in case the interrupt
    GPIO isn't available. And gpiod_get_value_cansleep() does cover this, too,
    by returning 0 in this case.
    Signed-off-by: default avatarDirk Behme <dirk.behme@de.bosch.com>
    Reviewed-by: default avatarHeiko Stuebner <heiko.stuebner@bq.com>
    Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
    62f46669
zforce_ts.txt 784 Bytes