tsl2550: fix lux1_input error in low light

ADC channel 0 photodiode detects both infrared + visible light,
but ADC channel 1 just detects infrared. However, the latter is a bit
more sensitive in that range so complete darkness or low light causes
a error condition in which the chan0 - chan1 is negative that
results in a -EAGAIN.

This patch changes the resulting lux1_input sysfs attribute message from
"Resource temporarily unavailable" to a user-grokable lux value of 0.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/tsl2550.c b/drivers/misc/tsl2550.c
index adf4607..3fce3b6 100644 (file)
--- a/drivers/misc/tsl2550.c
+++ b/drivers/misc/tsl2550.c
@@ -177,7 +177,7 @@ static int tsl2550_calculate_lux(u8 ch0, u8 ch1)
                } else
                        lux = 0;
        else
-               return -EAGAIN;
+               return 0;
 
        /* LUX range check */
        return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux;