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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>,
        "Lubomir Rintel" <lkundrak@v3.sk>,
        "Sebastian Reichel" <sebastian.reichel@collabora.com>,
        "Pavel Machek" <pavel@ucw.cz>
Date:   Tue, 02 Apr 2019 14:38:27 +0100
Message-ID: <lsq.1554212307.527416660@decadent.org.uk>
Subject: [PATCH 3.16 10/99] power: supply: olpc_battery: correct the
 temperature units
In-Reply-To: <lsq.1554212307.17110877@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.65-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Lubomir Rintel <lkundrak@v3.sk>

commit ed54ffbe554f0902689fd6d1712bbacbacd11376 upstream.

According to [1] and [2], the temperature values are in tenths of degree
Celsius. Exposing the Celsius value makes the battery appear on fire:

  $ upower -i /org/freedesktop/UPower/devices/battery_olpc_battery
  ...
      temperature:         236.9 degrees C

Tested on OLPC XO-1 and OLPC XO-1.75 laptops.

[1] include/linux/power_supply.h
[2] Documentation/power/power_supply_class.txt

Fixes: fb972873a767 ("[BATTERY] One Laptop Per Child power/battery driver")
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/power/olpc_battery.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/power/olpc_battery.c
+++ b/drivers/power/olpc_battery.c
@@ -425,14 +425,14 @@ static int olpc_bat_get_property(struct
 		if (ret)
 			return ret;
 
-		val->intval = (s16)be16_to_cpu(ec_word) * 100 / 256;
+		val->intval = (s16)be16_to_cpu(ec_word) * 10 / 256;
 		break;
 	case POWER_SUPPLY_PROP_TEMP_AMBIENT:
 		ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
 		if (ret)
 			return ret;
 
-		val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;
+		val->intval = (int)be16_to_cpu(ec_word) * 10 / 256;
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
 		ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);