On 27/01/16 22:46, Abhilash Jindal wrote:
> 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@xxxxxxxxx>
Seems sensible to me, but would like Richard / Harald to take a quick
look before I apply it.
Thanks,
Jonathan
> ---
> 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 1165b1c..cfc5a05 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);
>
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