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iio: dht11: Use boottime

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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 <klock.android@gmail.com>
Reviewed-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Abhilash Jindal 2016-01-27 17:46:02 -05:00 committed by Jonathan Cameron
parent ddeb35cbd6
commit 17a2f46c3d
1 changed files with 4 additions and 4 deletions
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8
drivers/iio/humidity/dht11.c
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@ -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);