From: Matt Ranostay <matt.ranostay@konsulko.com>
Date: Sat, 9 Jun 2018 06:58:15 +0000 (-0700)
Subject: tsl2550: fix lux1_input error in low light
X-Git-Tag: v4.14.74~137
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4804f372b53f65a9e04348ccfa494f169bbeadd9;p=platform%2Fkernel%2Flinux-rpi.git

tsl2550: fix lux1_input error in low light

[ 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>
---

diff --git a/drivers/misc/tsl2550.c b/drivers/misc/tsl2550.c
index adf4607..3fce3b6 100644
--- 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;