i2c/tsl2550: Fix lux value in dark environment (96f699ad) · Commits · 戴 / test

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:

Michele Jr De Candia <michele.decandia@valueteam.com> Acked-by:

Rodolfo Giometti <giometti@linux.it> Signed-off-by:

Jean Delvare <khali@linux-fr.org>

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;

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