From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f196.google.com ([209.85.223.196]:40933 "EHLO mail-io0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752652AbdK0XwK (ORCPT ); Mon, 27 Nov 2017 18:52:10 -0500 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 v3] hwmon: (pmbus) Use 64bit math for DIRECT format values Date: Mon, 27 Nov 2017 15:51:55 -0800 Message-Id: <20171127235155.91764-1-rlippert@google.com> In-Reply-To: <20171122220843.18309-1-rlippert@google.com> References: <20171122220843.18309-1-rlippert@google.com> Sender: linux-hwmon-owner@vger.kernel.org List-Id: linux-hwmon@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 | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index 52a58b8b6e1b..09977440bbea 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 +500,8 @@ 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 b, val = (s16) sensor->data; + s32 m, R; m = data->info->m[sensor->class]; b = data->info->b[sensor->class]; @@ -528,11 +529,12 @@ 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 +658,8 @@ 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, val64 = val; + s32 m, R; m = data->info->m[sensor->class]; b = data->info->b[sensor->class]; @@ -673,18 +676,18 @@ 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