From a6bffb6920d16fb2ef4ba072fac5b64b36b1c254 Mon Sep 17 00:00:00 2001 From: Harald Geyer Date: Sun, 11 Feb 2018 11:09:40 +0000 Subject: [PATCH] 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 Signed-off-by: Harald Geyer Signed-off-by: Jonathan Cameron --- drivers/iio/humidity/dht11.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c index df6bab40d6fa..1a9f8f4ffb88 100644 --- a/drivers/iio/humidity/dht11.c +++ b/drivers/iio/humidity/dht11.c @@ -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 = (3*256+232)*100 */ dht11->temperature = (((temp_int & 0x7f) << 8) + temp_dec) * ((temp_int & 0x80) ? -100 : 100); dht11->humidity = ((hum_int << 8) + hum_dec) * 100; -- 2.20.1