Commit a4493f22 authored Nov 27, 2017 by Arnd Bergmann Committed by Greg Kroah-Hartman Jan 08, 2018

iio: common: ssp_sensors: use ktime_get_real_ns() timestamps



getnstimeofday() suffers from the overflow in y2038 on 32-bit
architectures and requires a conversion into the nanosecond format that
we want here.

This changes ssp_parse_dataframe() to use ktime_get_real_ns() directly,
which does not have that problem.

An open question is what time base should be used here. Normally
timestamps should use ktime_get_ns() or ktime_get_boot_ns() to read
monotonic time instead of "real" time, which suffers from time jumps
due to settimeofday() calls or leap seconds.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 1b39eacd

drivers/iio/common/ssp_sensors/ssp_spi.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -277,12 +277,9 @@ static int ssp_handle_big_data(struct ssp_data data, char dataframe, int *idx)
		static int ssp_parse_dataframe(struct ssp_data data, char dataframe, int len)
		{
		int idx, sd;
		struct timespec ts;
		struct ssp_sensor_data *spd;
		struct iio_dev **indio_devs = data->sensor_devs;

		getnstimeofday(&ts);

		for (idx = 0; idx < len;) {
		switch (dataframe[idx++]) {
		case SSP_MSG2AP_INST_BYPASS_DATA:
		@@ -329,7 +326,7 @@ static int ssp_parse_dataframe(struct ssp_data data, char dataframe, int len)
		}

		if (data->time_syncing)
		data->timestamp = ts.tv_sec * 1000000000ULL + ts.tv_nsec;
		data->timestamp = ktime_get_real_ns();

		return 0;
		}