From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753320AbdK0VnZ (ORCPT ); Mon, 27 Nov 2017 16:43:25 -0500 Received: from mail-io0-f196.google.com ([209.85.223.196]:42561 "EHLO mail-io0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752456AbdK0VnO (ORCPT ); Mon, 27 Nov 2017 16:43:14 -0500 X-Google-Smtp-Source: AGs4zMakRNQsAkosHWfYa/WuVnErkV8d8N+n3VSRNBQbb5k5QxUOsEaepGIs0a4LJr2NkFN27bJn5A== From: Robert Lippert X-Google-Original-From: Robert Lippert To: linux@roeck-us.net Cc: linux-hwmon@vger.kernel.org, jdelvare@suse.com, linux-kernel@vger.kernel.org, xow@google.com, Robert Lippert Subject: [PATCH v2] hwmon: (pmbus) Use 64bit math for DIRECT format values Date: Mon, 27 Nov 2017 13:39:14 -0800 Message-Id: <20171127213914.141687-1-rlippert@google.com> X-Mailer: git-send-email 2.15.0.417.g466bffb3ac-goog In-Reply-To: <20171122220843.18309-1-rlippert@google.com> References: <20171122220843.18309-1-rlippert@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Power values in the 100s of watt range can easily blow past 32bit math limits when processing everything in microwatts. Use 64bit math instead to avoid these issues on common 32bit ARM BMC platforms. Signed-off-by: Robert Lippert --- drivers/hwmon/pmbus/pmbus_core.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index 52a58b8b6e1b..ff701502974a 100644 --- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -21,6 +21,7 @@ #include #include +#include #include #include #include @@ -499,8 +500,9 @@ static long pmbus_reg2data_linear(struct pmbus_data *data, static long pmbus_reg2data_direct(struct pmbus_data *data, struct pmbus_sensor *sensor) { - long val = (s16) sensor->data; - long m, b, R; + s64 val = (s16) sensor->data; + s64 b, R; + s32 m; m = data->info->m[sensor->class]; b = data->info->b[sensor->class]; @@ -528,11 +530,12 @@ static long pmbus_reg2data_direct(struct pmbus_data *data, R--; } while (R < 0) { - val = DIV_ROUND_CLOSEST(val, 10); + val = div_s64(val + 5LL, 10L); // round closest R++; } - return (val - b) / m; + val = div_s64(val - b, m); + return clamp_val(val, LONG_MIN, LONG_MAX); } /* @@ -656,7 +659,9 @@ static u16 pmbus_data2reg_linear(struct pmbus_data *data, static u16 pmbus_data2reg_direct(struct pmbus_data *data, struct pmbus_sensor *sensor, long val) { - long m, b, R; + s64 b, R; + s32 m; + s64 val64 = val; m = data->info->m[sensor->class]; b = data->info->b[sensor->class]; @@ -673,18 +678,18 @@ static u16 pmbus_data2reg_direct(struct pmbus_data *data, R -= 3; /* Adjust R and b for data in milli-units */ b *= 1000; } - val = val * m + b; + val64 = val64 * m + b; while (R > 0) { - val *= 10; + val64 *= 10; R--; } while (R < 0) { - val = DIV_ROUND_CLOSEST(val, 10); + val64 = div_s64(val64 + 5LL, 10L); // round closest R++; } - return val; + return (u16) clamp_val(val64, S16_MIN, S16_MAX); } static u16 pmbus_data2reg_vid(struct pmbus_data *data, -- 2.15.0.417.g466bffb3ac-goog