From 17a2f46c3d8877fe2a0b6ff391d1df30e67892a6 Mon Sep 17 00:00:00 2001 From: Abhilash Jindal Date: Wed, 27 Jan 2016 17:46:02 -0500 Subject: [PATCH] iio: dht11: Use boottime Wall time obtained from ktime_get_real_ns is susceptible to sudden jumps due to user setting the time or due to NTP. Boot time is constantly increasing time better suited for comparing two timestamps. Signed-off-by: Abhilash Jindal Reviewed-by: Harald Geyer Signed-off-by: Jonathan Cameron --- drivers/iio/humidity/dht11.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c index 1165b1c4f9d6..cfc5a051ab9f 100644 --- a/drivers/iio/humidity/dht11.c +++ b/drivers/iio/humidity/dht11.c @@ -117,7 +117,7 @@ static int dht11_decode(struct dht11 *dht11, int offset, int timeres) if (((hum_int + hum_dec + temp_int + temp_dec) & 0xff) != checksum) return -EIO; - dht11->timestamp = ktime_get_real_ns(); + dht11->timestamp = ktime_get_boot_ns(); if (hum_int < 20) { /* DHT22 */ dht11->temperature = (((temp_int & 0x7f) << 8) + temp_dec) * ((temp_int & 0x80) ? -100 : 100); @@ -145,7 +145,7 @@ static irqreturn_t dht11_handle_irq(int irq, void *data) /* TODO: Consider making the handler safe for IRQ sharing */ if (dht11->num_edges < DHT11_EDGES_PER_READ && dht11->num_edges >= 0) { - dht11->edges[dht11->num_edges].ts = ktime_get_real_ns(); + dht11->edges[dht11->num_edges].ts = ktime_get_boot_ns(); dht11->edges[dht11->num_edges++].value = gpio_get_value(dht11->gpio); @@ -164,7 +164,7 @@ static int dht11_read_raw(struct iio_dev *iio_dev, int ret, timeres; mutex_lock(&dht11->lock); - if (dht11->timestamp + DHT11_DATA_VALID_TIME < ktime_get_real_ns()) { + if (dht11->timestamp + DHT11_DATA_VALID_TIME < ktime_get_boot_ns()) { timeres = ktime_get_resolution_ns(); if (DHT11_DATA_BIT_HIGH < 2 * timeres) { dev_err(dht11->dev, "timeresolution %dns too low\n", @@ -279,7 +279,7 @@ static int dht11_probe(struct platform_device *pdev) return -EINVAL; } - dht11->timestamp = ktime_get_real_ns() - DHT11_DATA_VALID_TIME - 1; + dht11->timestamp = ktime_get_boot_ns() - DHT11_DATA_VALID_TIME - 1; dht11->num_edges = -1; platform_set_drvdata(pdev, iio); -- 2.30.2