From 96f699ad09c8b3c55cd229506a9add0047838e3e Mon Sep 17 00:00:00 2001 From: Michele Jr De Candia Date: Tue, 28 Jul 2009 16:33:03 +0200 Subject: [PATCH] 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: Michele Jr De Candia Acked-by: Rodolfo Giometti Signed-off-by: Jean Delvare --- drivers/i2c/chips/tsl2550.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/i2c/chips/tsl2550.c b/drivers/i2c/chips/tsl2550.c index 1a9cc135219..b96f3025e58 100644 --- a/drivers/i2c/chips/tsl2550.c +++ b/drivers/i2c/chips/tsl2550.c @@ -27,7 +27,7 @@ #include #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)) - r = c1 * 128 / c0; + if (c1 <= c0) + if (c0) { + r = c1 * 128 / c0; + + /* Calculate LUX */ + lux = ((c0 - c1) * ratio_lut[r]) / 256; + } else + lux = 0; else - return -1; - - /* Calculate LUX */ - lux = ((c0 - c1) * ratio_lut[r]) / 256; + return -EAGAIN; /* LUX range check */ return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux; -- 2.20.1