| Message ID | 1518347380-9624-1-git-send-email-harald@ccbib.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, 11 Feb 2018 11:09:40 +0000 Harald Geyer <harald@ccbib.org> wrote: > 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> Applied to the togreg branch of iio.git and pushed out as testing for the autobuilders to play with it. Thanks, Jonathan > --- > 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 df6bab4..1a9f8f4 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; -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c index df6bab4..1a9f8f4 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;
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> --- drivers/iio/humidity/dht11.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)