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Commit 96f699ad authored by Michele Jr De Candia's avatar Michele Jr De Candia Committed by Jean Delvare
Browse files

i2c/tsl2550: Fix lux value in dark environment 



I've tested TSL2550 driver and I've found a bug: when light is off, 
returned value from tsl2550_calculate_lux function is -1 when it should 
be 0 (sensor correctly read that light was off).

I think the bug is that a zero c0 value (approximated value of ch0) is 
misinterpreted as an error. 

Signed-off-by: default avatarMichele Jr De Candia <michele.decandia@valueteam.com>
Acked-by: default avatarRodolfo Giometti <giometti@linux.it>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 4733fd32

drivers/i2c/chips/tsl2550.c

+10 −7
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ 
#include <linux/delay.h>



#define TSL2550_DRV_NAME	"tsl2550"

#define DRIVER_VERSION		"1.1.1"

#define DRIVER_VERSION		"1.1.2"



/*

 * Defines
@@ -189,13 +189,16 @@ static int tsl2550_calculate_lux(u8 ch0, u8 ch1) 
	u8 r = 128;



	/* Avoid division by 0 and count 1 cannot be greater than count 0 */

	if (c0 && (c1 <= c0))

	if (c1 <= c0)

		if (c0) {

			r = c1 * 128 / c0;

	else

		return -1;



			/* Calculate LUX */

			lux = ((c0 - c1) * ratio_lut[r]) / 256;

		} else

			lux = 0;

	else

		return -EAGAIN;



	/* LUX range check */

	return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux;