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Commit 432121ad authored by Amit Kucheria's avatar Amit Kucheria Committed by Eduardo Valentin
Browse files

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: default avatarAmit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: default avatarMatthias Kaehlcke <mka@chromium.org>
Reviewed-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: default avatarEduardo Valentin <edubezval@gmail.com>
parent faa590ba

drivers/thermal/qcom/tsens-v2.c

+5 −8
Original line number Diff line number Diff line
@@ -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;

}