From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-path: Received: from bh-25.webhostbox.net ([208.91.199.152]:57509 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752715AbdGHPpT (ORCPT ); Sat, 8 Jul 2017 11:45:19 -0400 Date: Sat, 8 Jul 2017 08:45:15 -0700 From: Guenter Roeck To: Tom Levens Cc: Rob Herring , Mark Rutland , Jean Delvare , Mike Looijmans , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org Subject: Re: [v3,1/3] hwmon: ltc2990: refactor value conversion Message-ID: <20170708154515.GA6358@roeck-us.net> References: <1499056140-6064-1-git-send-email-tom.levens@cern.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1499056140-6064-1-git-send-email-tom.levens@cern.ch> Sender: linux-hwmon-owner@vger.kernel.org List-Id: linux-hwmon@vger.kernel.org On Mon, Jul 03, 2017 at 06:28:58AM +0200, Tom Levens wrote: > Conversion from raw values to signed integers has been refactored using > bitops.h. This also fixes a bug where negative temperatures were > converted incorrectly. > Documentation/process/submitting-patches.rst, chapter 2: "Solve only one problem per patch.". I can understand the urge to merge two sets of changes here. However, that creates a problem for me: The fix should be applied to stable kernels, but not the refactoring. Please split the patch in two, one for the bug fix and one for the refactoring. Thanks, Guenter > Signed-off-by: Tom Levens > --- > drivers/hwmon/ltc2990.c | 18 ++++-------------- > 1 file changed, 4 insertions(+), 14 deletions(-) > > diff --git a/drivers/hwmon/ltc2990.c b/drivers/hwmon/ltc2990.c > index 8f8fe05..e320d21 100644 > --- a/drivers/hwmon/ltc2990.c > +++ b/drivers/hwmon/ltc2990.c > @@ -11,6 +11,7 @@ > * the chip's internal temperature and Vcc power supply voltage. > */ > > +#include > #include > #include > #include > @@ -34,15 +35,6 @@ > #define LTC2990_CONTROL_MODE_CURRENT 0x06 > #define LTC2990_CONTROL_MODE_VOLTAGE 0x07 > > -/* convert raw register value to sign-extended integer in 16-bit range */ > -static int ltc2990_voltage_to_int(int raw) > -{ > - if (raw & BIT(14)) > - return -(0x4000 - (raw & 0x3FFF)) << 2; > - else > - return (raw & 0x3FFF) << 2; > -} > - > /* Return the converted value from the given register in uV or mC */ > static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, int *result) > { > @@ -55,18 +47,16 @@ static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, int *result) > switch (reg) { > case LTC2990_TINT_MSB: > /* internal temp, 0.0625 degrees/LSB, 13-bit */ > - val = (val & 0x1FFF) << 3; > - *result = (val * 1000) >> 7; > + *result = sign_extend32(val, 12) * 1000 / 16; > break; > case LTC2990_V1_MSB: > case LTC2990_V3_MSB: > /* Vx-Vy, 19.42uV/LSB. Depends on mode. */ > - *result = ltc2990_voltage_to_int(val) * 1942 / (4 * 100); > + *result = sign_extend32(val, 14) * 1942 / 100; > break; > case LTC2990_VCC_MSB: > /* Vcc, 305.18μV/LSB, 2.5V offset */ > - *result = (ltc2990_voltage_to_int(val) * 30518 / > - (4 * 100 * 1000)) + 2500; > + *result = sign_extend32(val, 14) * 30518 / (100 * 1000) + 2500; > break; > default: > return -EINVAL; /* won't happen, keep compiler happy */