• Alexandru Tachici's avatar
    iio: adc: ad7124: Fix DT channel configuration · d7857e4e
    Alexandru Tachici authored
    This patch fixes device tree channel configuration.
    
    ad7124 driver reads channels configuration from the device tree.
    It expects to find channel specifications as child nodes.
    Before this patch ad7124 driver assumed that the child nodes are parsed
    by for_each_available_child_of_node in the order 0,1,2,3...
    
    This is wrong and the real order of the children can be seen by running:
    dtc -I fs /sys/firmware/devicetree/base on the machine.
    
    For example, running this on an rpi 3B+ yields the real
    children order: 4,2,0,7,5,3,1,6
    
    Before this patch the driver assigned the channel configuration
    like this:
            - 0 <- 4
            - 1 <- 2
            - 2 <- 0
            ........
    For example, the symptoms can be observed by connecting the 4th channel
    to a 1V tension and then reading the in_voltage0-voltage19_raw sysfs
    (multiplied of course by the scale) one would see that channel 0
    measures 1V and channel 4 measures only noise.
    
    Now the driver uses the reg property of each child in order to
    correctly identify to which channel the parsed configuration
    belongs to.
    
    Fixes b3af341b: ("iio: adc: Add ad7124 support")
    Signed-off-by: default avatarAlexandru Tachici <alexandru.tachici@analog.com>
    Cc: <Stable@vger.kernel.org>
    Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    d7857e4e
ad7124.c 17.4 KB