thermal: tsens: Fix negative temperature reporting

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@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
This commit is contained in:
Amit Kucheria 2018-07-26 16:03:10 +05:30 committed by Eduardo Valentin
parent faa590baf8
commit 432121adf5
1 changed files with 5 additions and 8 deletions

View File

@ -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;
}