An sht3x sensor include limits register which contains temperature and humidity limit values. After a reset, pre-defined values are loaded into that register. During the probe function, the driver reads the limits register. However, if the reads are made too early, for example because the I2C bus frequency is high (e.g. 400 kHz), the loading could be not completed and the sensor returns a NACK which causes the probe to fail. A delay of at least 500 us before the first read solves this issue. Signed-off-by: Emiliano Ingrassia <ingrassia@xxxxxxxxxxxxxx> --- drivers/hwmon/sht3x.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/hwmon/sht3x.c b/drivers/hwmon/sht3x.c index 6ea99cd6ae79..f2098443df2f 100644 --- a/drivers/hwmon/sht3x.c +++ b/drivers/hwmon/sht3x.c @@ -732,6 +732,9 @@ static int sht3x_probe(struct i2c_client *client, mutex_init(&data->i2c_lock); mutex_init(&data->data_lock); + /* wait predefined limits loading complete before access */ + usleep_range(500, 600); + ret = limits_update(data); if (ret) return ret; -- 2.15.1 -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
