Messages in this thread Patch in this message | | | Date | Thu, 13 Aug 2009 12:40:24 -0700 | From | Greg KH <> | Subject | [patch 03/28] i2c/tsl2550: Fix lux value in dark environment |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
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From: Michele Jr De Candia <michele.decandia@valueteam.com>
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>
--- drivers/i2c/chips/tsl2550.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-)
--- 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 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;
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