The current code will always return 0xffffffff in case of negative
temperatures due to a bug in how the binary sign extension is being done.
Use sign_extend32() instead.
Signed-off-by: Amit Kucheria <amit.kucheria@xxxxxxxxxx>
Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---
drivers/thermal/qcom/tsens-v2.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/drivers/thermal/qcom/tsens-v2.c b/drivers/thermal/qcom/tsens-v2.c
index 908e3dcb2d5c..44da02f594ac 100644
--- a/drivers/thermal/qcom/tsens-v2.c
+++ b/drivers/thermal/qcom/tsens-v2.c
@@ -5,19 +5,20 @@
*/
#include <linux/regmap.h>
+#include <linux/bitops.h>
#include "tsens.h"
#define STATUS_OFFSET 0xa0
#define LAST_TEMP_MASK 0xfff
#define STATUS_VALID_BIT BIT(21)
-#define CODE_SIGN_BIT BIT(11)
static int get_temp_tsens_v2(struct tsens_device *tmdev, int id, int *temp)
{
struct tsens_sensor *s = &tmdev->sensor[id];
u32 code;
unsigned int status_reg;
- int last_temp = 0, last_temp2 = 0, last_temp3 = 0, ret;
+ u32 last_temp = 0, last_temp2 = 0, last_temp3 = 0;
+ int ret;
status_reg = tmdev->tm_offset + STATUS_OFFSET + s->hw_id * 4;
ret = regmap_read(tmdev->map, status_reg, &code);
@@ -54,12 +55,8 @@ static int get_temp_tsens_v2(struct tsens_device *tmdev, int id, int *temp)
else if (last_temp2 == last_temp3)
last_temp = last_temp3;
done:
- /* Code sign bit is the sign extension for a negative value */
- if (last_temp & CODE_SIGN_BIT)
- last_temp |= ~CODE_SIGN_BIT;
-
- /* Temperatures are in deciCelicius */
- *temp = last_temp * 100;
+ /* Convert temperature from deciCelsius to milliCelsius */
+ *temp = sign_extend32(last_temp, fls(LAST_TEMP_MASK) - 1) * 100;
return 0;
}
--
2.17.GIT
--
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