Commit a6bffb69 authored Feb 11, 2018 by Harald Geyer Committed by Jonathan Cameron Feb 17, 2018

iio: dht11: Improve detection of sensor type



The old code was based on a DHT11 datasheet which specifies a measurement
range of 20%-90% RH. Turns out the sensor actually reports values outside
this range, so we should support it as far as possible.

Reported-by: Edward Attfield <edward@attfield.ca>
Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

parent 7fe2241c

drivers/iio/humidity/dht11.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -159,7 +159,7 @@ static int dht11_decode(struct dht11 *dht11, int offset)
		}

		dht11->timestamp = ktime_get_boot_ns();
		if (hum_int < 20) { /* DHT22 */
		if (hum_int < 4) { /* DHT22: 100000 = (3256+232)100 */
		dht11->temperature = (((temp_int & 0x7f) << 8) + temp_dec) *
		((temp_int & 0x80) ? -100 : 100);
		dht11->humidity = ((hum_int << 8) + hum_dec) * 100;

Admin message