tsl2550: fix lux1_input error in low light
authorMatt Ranostay <matt.ranostay@konsulko.com>
Sat, 9 Jun 2018 06:58:15 +0000 (23:58 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 4 Oct 2018 00:00:45 +0000 (17:00 -0700)
[ Upstream commit ce054546cc2c26891cefa2f284d90d93b52205de ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/misc/tsl2550.c

index adf46072cb37d4a41a3ec95a9fd7d8a52890e677..3fce3b6a36246b28f9c81e339ba83bc67f0a08d2 100644 (file)
@@ -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;