From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AB66CBA49 for ; Tue, 7 Mar 2023 18:52:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D525C433EF; Tue, 7 Mar 2023 18:52:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678215174; bh=LQcjWHSK0t8axOX1xwGU3uCI7fw5qyf5YkeNveO4wPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=v4d/95kQVni/Qs1ZZiCnZUC98SuibieDEgnb9OT5oV0gNWeAM5gBZyX+Lpb4zZy6O eupoNJLBK8nVE8dVFXeaEPgVdBUurU9QJrmIz8RDDoIaOGoo2VF4fWwBzrZa8LdD0H ogxe8qvg2xhjFOFVPJCxj/SEmQ5JUtUq4qveMDJ0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Armin Wolf , Guenter Roeck , Sasha Levin Subject: [PATCH 5.15 175/567] hwmon: (ftsteutates) Fix scaling of measurements Date: Tue, 7 Mar 2023 17:58:31 +0100 Message-Id: <20230307165913.545810936@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307165905.838066027@linuxfoundation.org> References: <20230307165905.838066027@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Armin Wolf [ Upstream commit ca8fd8c16a8b77dfcf7f6ce52d2c863220693a78 ] A user complained that the ftsteutates driver was displaying bogus values since its introduction. This happens because the sensor measurements need to be scaled in order to produce meaningful results: - the fan speed needs to be multiplied by 60 since its in RPS - the temperature is in degrees celsius and needs an offset of 64 - the voltage is in 1/256 of 3.3V The offical datasheet says the voltage needs to be divided by 256, but this is likely an off-by-one-error, since even the BIOS devides by 255 (otherwise 3.3V could not be measured). The voltage channels additionally need a board-specific multiplier, however this can be done by the driver since its board-specific. The reason the missing scaling of measurements is the way Fujitsu used this driver when it was still out-of-tree. Back then, all scaling was done in userspace by libsensors, even the generic one. Tested on a Fujitsu DS3401-B1. Fixes: 08426eda58e0 ("hwmon: Add driver for FTS BMC chip "Teutates"") Signed-off-by: Armin Wolf Link: https://lore.kernel.org/r/20221224041855.83981-2-W_Armin@gmx.de Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin --- Documentation/hwmon/ftsteutates.rst | 4 ++++ drivers/hwmon/ftsteutates.c | 19 +++++++++++++------ 2 files changed, 17 insertions(+), 6 deletions(-) diff --git a/Documentation/hwmon/ftsteutates.rst b/Documentation/hwmon/ftsteutates.rst index 58a2483d8d0da..198fa8e2819da 100644 --- a/Documentation/hwmon/ftsteutates.rst +++ b/Documentation/hwmon/ftsteutates.rst @@ -22,6 +22,10 @@ enhancements. It can monitor up to 4 voltages, 16 temperatures and 8 fans. It also contains an integrated watchdog which is currently implemented in this driver. +The 4 voltages require a board-specific multiplier, since the BMC can +only measure voltages up to 3.3V and thus relies on voltage dividers. +Consult your motherboard manual for details. + To clear a temperature or fan alarm, execute the following command with the correct path to the alarm file:: diff --git a/drivers/hwmon/ftsteutates.c b/drivers/hwmon/ftsteutates.c index ceffc76a0c515..2998d8cdce006 100644 --- a/drivers/hwmon/ftsteutates.c +++ b/drivers/hwmon/ftsteutates.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -347,13 +348,15 @@ static ssize_t in_value_show(struct device *dev, { struct fts_data *data = dev_get_drvdata(dev); int index = to_sensor_dev_attr(devattr)->index; - int err; + int value, err; err = fts_update_device(data); if (err < 0) return err; - return sprintf(buf, "%u\n", data->volt[index]); + value = DIV_ROUND_CLOSEST(data->volt[index] * 3300, 255); + + return sprintf(buf, "%d\n", value); } static ssize_t temp_value_show(struct device *dev, @@ -361,13 +364,15 @@ static ssize_t temp_value_show(struct device *dev, { struct fts_data *data = dev_get_drvdata(dev); int index = to_sensor_dev_attr(devattr)->index; - int err; + int value, err; err = fts_update_device(data); if (err < 0) return err; - return sprintf(buf, "%u\n", data->temp_input[index]); + value = (data->temp_input[index] - 64) * 1000; + + return sprintf(buf, "%d\n", value); } static ssize_t temp_fault_show(struct device *dev, @@ -436,13 +441,15 @@ static ssize_t fan_value_show(struct device *dev, { struct fts_data *data = dev_get_drvdata(dev); int index = to_sensor_dev_attr(devattr)->index; - int err; + int value, err; err = fts_update_device(data); if (err < 0) return err; - return sprintf(buf, "%u\n", data->fan_input[index]); + value = data->fan_input[index] * 60; + + return sprintf(buf, "%d\n", value); } static ssize_t fan_source_show(struct device *dev, -- 2.39.2