diff options
| author | Michele Jr De Candia <michele.decandia@valueteam.com> | 2009-07-28 16:33:03 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-08-16 14:26:23 -0700 |
| commit | dd2d70a7ba542030c152cdc224d3d303e9b6e21a (patch) | |
| tree | 123f3ecacec4e7d0f5e93dfccb00c62b26857822 | |
| parent | 49a8cf1d49e9c956fcbc999018126804309887d7 (diff) | |
i2c/tsl2550: Fix lux value in dark environment
commit 96f699ad09c8b3c55cd229506a9add0047838e3e upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/i2c/chips/tsl2550.c | 17 |
1 files 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 <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)) - 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; |