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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, chris.healy@zii.aero,
        Andrew Lunn <andrew@lunn.ch>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.19 13/50] net: phy: sfp: hwmon: Fix scaling of RX power
Date:   Fri, 26 Jul 2019 17:24:48 +0200
Message-Id: <20190726152301.937711203@linuxfoundation.org>
In-Reply-To: <20190726152300.760439618@linuxfoundation.org>
References: <20190726152300.760439618@linuxfoundation.org>
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From: Andrew Lunn <andrew@lunn.ch>

[ Upstream commit 0cea0e1148fe134a4a3aaf0b1496f09241fb943a ]

The RX power read from the SFP uses units of 0.1uW. This must be
scaled to units of uW for HWMON. This requires a divide by 10, not the
current 100.

With this change in place, sensors(1) and ethtool -m agree:

sff2-isa-0000
Adapter: ISA adapter
in0:          +3.23 V
temp1:        +33.1 C
power1:      270.00 uW
power2:      200.00 uW
curr1:        +0.01 A

        Laser output power                        : 0.2743 mW / -5.62 dBm
        Receiver signal average optical power     : 0.2014 mW / -6.96 dBm

Reported-by: chris.healy@zii.aero
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Fixes: 1323061a018a ("net: phy: sfp: Add HWMON support for module sensors")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/phy/sfp.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -514,7 +514,7 @@ static int sfp_hwmon_read_sensor(struct
 
 static void sfp_hwmon_to_rx_power(long *value)
 {
-	*value = DIV_ROUND_CLOSEST(*value, 100);
+	*value = DIV_ROUND_CLOSEST(*value, 10);
 }
 
 static void sfp_hwmon_calibrate(struct sfp *sfp, unsigned int slope, int offset,