iio: adc: ti-ads1015: avoid getting stale result after runtime resume
BugLink: http://bugs.launchpad.net/bugs/1716284
commit
73e3e3fc50de50cfd68e945d85679c983ed31bd9 upstream.
This driver assumes that the device is operating in the continuous
conversion mode which performs the conversion continuously. So this driver
doesn't insert a wait time before reading the conversion register if the
configuration is not changed from a previous request.
This assumption is broken if the device is runtime suspended and entered
a power-down state. The forthcoming request causes reading a stale result
from the conversion register as the device is runtime resumed just before.
Fix it by adding a flag to detect that condition and insert a necessary
wait time.
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>