Author: gavin
Date: Thu Dec 22 00:09:53 2016
New Revision: 310381
URL: https://svnweb.freebsd.org/changeset/base/310381
Log:
ow_temp: Update the temperature visible via the sysctl atomically, rather
than using it as temporary calculation space.
Modified:
head/sys/dev/ow/ow_temp.c
Modified: head/sys/dev/ow/ow_temp.c
==============================================================================
--- head/sys/dev/ow/ow_temp.c Wed Dec 21 23:59:58 2016 (r310380)
+++ head/sys/dev/ow/ow_temp.c Thu Dec 22 00:09:53 2016 (r310381)
@@ -137,7 +137,7 @@ ow_temp_event_thread(void *arg)
struct ow_temp_softc *sc;
uint8_t scratch[8 + 1];
uint8_t crc;
- int retries, rv;
+ int retries, rv, tmp;
sc = arg;
pause("owtstart", device_get_unit(sc->dev) * hz / 100); // 10ms stagger
@@ -166,14 +166,14 @@ ow_temp_event_thread(void *arg)
* Formula from DS18S20
datasheet, page 6
* DS18S20 datasheet
says count_per_c is 16, DS1820 does not
*/
- sc->temp =
(int16_t)((scratch[0] & 0xfe) |
+ tmp =
(int16_t)((scratch[0] & 0xfe) |
(scratch[1] << 8))
<< 3;
- sc->temp += 16 -
scratch[6] - 4; /* count_per_c == 16 */
+ tmp += 16 - scratch[6]
- 4; /* count_per_c == 16 */
} else
- sc->temp =
(int16_t)(scratch[0] | (scratch[1] << 8)) << 3;
+ tmp =
(int16_t)(scratch[0] | (scratch[1] << 8)) << 3;
} else
- sc->temp = (int16_t)(scratch[0]
| (scratch[1] << 8));
- sc->temp = sc->temp * 1000 / 16 +
273150;
+ tmp = (int16_t)(scratch[0] |
(scratch[1] << 8));
+ sc->temp = tmp * 1000 / 16 + 273150;
break;
}
sc->bad_crc++;
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