iio: dht11: Use usleep_range instead of msleep for start signal

[sfrench/cifs-2.6.git] / drivers / iio / humidity / dht11.c

diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c
index 9c47bc98f3acdea4cb4b56b23a72e582c34a413b..2a22ad92033306d02eec60f288c00a65d5186c37 100644 (file)
--- a/drivers/iio/humidity/dht11.c
+++ b/drivers/iio/humidity/dht11.c
@@ -71,7 +71,8 @@
  * a) select an implementation using busy loop polling on those systems
  * b) use the checksum to do some probabilistic decoding
  */
-#define DHT11_START_TRANSMISSION       18  /* ms */
+#define DHT11_START_TRANSMISSION_MIN   18000  /* us */
+#define DHT11_START_TRANSMISSION_MAX   20000  /* us */
 #define DHT11_MIN_TIMERES      34000  /* ns */
 #define DHT11_THRESHOLD                49000  /* ns */
 #define DHT11_AMBIG_LOW                23000  /* ns */
@@ -228,7 +229,8 @@ static int dht11_read_raw(struct iio_dev *iio_dev,
                ret = gpio_direction_output(dht11->gpio, 0);
                if (ret)
                        goto err;
-               msleep(DHT11_START_TRANSMISSION);
+               usleep_range(DHT11_START_TRANSMISSION_MIN,
+                            DHT11_START_TRANSMISSION_MAX);
                ret = gpio_direction_input(dht11->gpio);
                if (ret)
                        goto err;