From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from bh-25.webhostbox.net ([208.91.199.152]:37333 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750927AbcJDWRC (ORCPT ); Tue, 4 Oct 2016 18:17:02 -0400 Date: Tue, 4 Oct 2016 15:16:55 -0700 From: Guenter Roeck To: Chris Packham Cc: jdelvare@suse.com, linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, Michael.Wang@alliedtelesis.co.nz Subject: Re: [PATCHv2] hwmon: adm9240: handle temperature readings below 0 Message-ID: <20161004221655.GA436@roeck-us.net> References: <20161004214054.18501-1-chris.packham@alliedtelesis.co.nz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161004214054.18501-1-chris.packham@alliedtelesis.co.nz> Sender: linux-hwmon-owner@vger.kernel.org List-Id: linux-hwmon@vger.kernel.org On Wed, Oct 05, 2016 at 10:40:54AM +1300, Chris Packham wrote: > Unlike the temperature thresholds the temperature data is a 9-bit signed > value. This allows and additional 0.5 degrees of precision on the > reading but makes handling negative values slightly harder. In order to > have sign-extension applied correctly the 9-bit value is stored in the > upper bits of a signed 16-bit value. When presenting this in sysfs the > value is shifted and scaled appropriately. > > Signed-off-by: Chris Packham Applied (after removing the extra () in the data->temp assignment). Thanks, Guenter > --- > Changes in v2: > - Simplify as per feedback from Guenter. > - Re-word commit message. > > drivers/hwmon/adm9240.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwmon/adm9240.c b/drivers/hwmon/adm9240.c > index 98114ce..8d8ede8 100644 > --- a/drivers/hwmon/adm9240.c > +++ b/drivers/hwmon/adm9240.c > @@ -197,7 +197,7 @@ static struct adm9240_data *adm9240_update_device(struct device *dev) > data->temp = ((i2c_smbus_read_byte_data(client, > ADM9240_REG_TEMP) << 8) | > i2c_smbus_read_byte_data(client, > - ADM9240_REG_TEMP_CONF)) / 128; > + ADM9240_REG_TEMP_CONF)); > > for (i = 0; i < 2; i++) { /* read fans */ > data->fan[i] = i2c_smbus_read_byte_data(client, > @@ -263,7 +263,7 @@ static ssize_t show_temp(struct device *dev, struct device_attribute *dummy, > char *buf) > { > struct adm9240_data *data = adm9240_update_device(dev); > - return sprintf(buf, "%d\n", data->temp * 500); /* 9-bit value */ > + return sprintf(buf, "%d\n", data->temp / 128 * 500); /* 9-bit value */ > } > > static ssize_t show_max(struct device *dev, struct device_attribute *devattr, > -- > 2.10.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html