When the LM75 temperature sensor measures a temperature below 0 C, the
current driver does not perform sign extension, so the result returned is
256 C too high. This patch fixes the problem.
Signed-off-by: Larry Johnson <[EMAIL PROTECTED]>
---
The patch was tested on the AMCC Sequoia board, which uses the AD7414
temperature sensor. It appears that other drivers, such as "ds1621.c",
may have the same bug, but I have no way of testing these.
drivers/hwmon/lm75.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index 63f3b75..e29b294 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -179,7 +179,13 @@ int dtt_init (void)
int dtt_get_temp(int sensor)
{
- return (dtt_read(sensor, DTT_READ_TEMP) / 256);
+ int const ret = dtt_read(sensor, DTT_READ_TEMP);
+
+ if (ret < 0) {
+ printf("DTT temperature read failed.\n");
+ return 0;
+ }
+ return (int)((int16_t) ret / 256);
} /* dtt_get_temp() */
#endif /* CONFIG_DTT_LM75 */
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