From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22F67C43217 for ; Thu, 7 Jan 2021 10:32:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DA3D82336F for ; Thu, 7 Jan 2021 10:32:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727590AbhAGKbt (ORCPT ); Thu, 7 Jan 2021 05:31:49 -0500 Received: from mx0a-00128a01.pphosted.com ([148.163.135.77]:52108 "EHLO mx0a-00128a01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726110AbhAGKbs (ORCPT ); Thu, 7 Jan 2021 05:31:48 -0500 Received: from pps.filterd (m0167088.ppops.net [127.0.0.1]) by mx0a-00128a01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 107AUhLq013617; Thu, 7 Jan 2021 05:30:52 -0500 Received: from nwd2mta4.analog.com ([137.71.173.58]) by mx0a-00128a01.pphosted.com with ESMTP id 35wsv6gwm0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 07 Jan 2021 05:30:51 -0500 Received: from ASHBMBX9.ad.analog.com (ASHBMBX9.ad.analog.com [10.64.17.10]) by nwd2mta4.analog.com (8.14.7/8.14.7) with ESMTP id 107AUouP023977 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=FAIL); Thu, 7 Jan 2021 05:30:50 -0500 Received: from ASHBMBX8.ad.analog.com (10.64.17.5) by ASHBMBX9.ad.analog.com (10.64.17.10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Thu, 7 Jan 2021 05:30:49 -0500 Received: from zeus.spd.analog.com (10.66.68.11) by ashbmbx8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server id 15.2.721.2 via Frontend Transport; Thu, 7 Jan 2021 05:30:49 -0500 Received: from localhost.localdomain ([10.48.65.12]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 107AUhsj013109; Thu, 7 Jan 2021 05:30:47 -0500 From: Alexandru Ardelean To: , , CC: , , , , , Alexandru Ardelean Subject: [PATCH v3 2/4] hwmon: (ltc2945): clamp values before converting Date: Thu, 7 Jan 2021 12:34:15 +0200 Message-ID: <20210107103417.16010-3-alexandru.ardelean@analog.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210107103417.16010-1-alexandru.ardelean@analog.com> References: <20210107103417.16010-1-alexandru.ardelean@analog.com> MIME-Version: 1.0 Content-Type: text/plain X-ADIRuleOP-NewSCL: Rule Triggered X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343,18.0.737 definitions=2021-01-07_05:2021-01-07,2021-01-07 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 impostorscore=0 malwarescore=0 mlxlogscore=999 mlxscore=0 adultscore=0 suspectscore=0 bulkscore=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101070063 Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org We can compute the full-scale values for power, voltages and current, and apply them before conversion. This way we sanitize the input from userspace a bit. We can't however clamp the value for power, since that is represented in micro-Watts. The full-scale power that can be represented is around 10480 Watts, which in micro-Watts ends up being around 10 billion micro-Watts. Current and voltage is represented in millis, so these can be clamped. Signed-off-by: Alexandru Ardelean --- drivers/hwmon/ltc2945.c | 48 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/drivers/hwmon/ltc2945.c b/drivers/hwmon/ltc2945.c index 42a59170da78..41df2c8b7673 100644 --- a/drivers/hwmon/ltc2945.c +++ b/drivers/hwmon/ltc2945.c @@ -58,6 +58,15 @@ #define CONTROL_MULT_SELECT (1 << 0) #define CONTROL_TEST_MODE (1 << 4) +/* Full scale ranges (page 4 of the datasheet) */ + +#define LTC2945_VIN_FULL_SCALE_MV 102375 +#define LTC2945_ADIN_FULL_SCALE_MV 2048 + +/* Power and current computed assuming a 1mOhm sense resistor */ +#define LTC2945_POWER_FULL_SCALE_UW 10485759375ULL +#define LTC2945_SENSE_FULL_SCALE_MA 102375 + /** * struct ltc2945_state - driver instance specific data * @regmap: regmap object to access device registers @@ -154,6 +163,43 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg) return val; } +static unsigned long ltc2945_val_clamp(u8 reg, unsigned long val) +{ + switch (reg) { + case LTC2945_POWER_H: + case LTC2945_MAX_POWER_H: + case LTC2945_MIN_POWER_H: + case LTC2945_MAX_POWER_THRES_H: + case LTC2945_MIN_POWER_THRES_H: + /* No sense in clamping now, LTC2945_POWER_FULL_SCALE_UW is larger than UINT32_MAX */ + return val; + case LTC2945_VIN_H: + case LTC2945_MAX_VIN_H: + case LTC2945_MIN_VIN_H: + case LTC2945_MAX_VIN_THRES_H: + case LTC2945_MIN_VIN_THRES_H: + return clamp_val(val, 0, LTC2945_VIN_FULL_SCALE_MV); + case LTC2945_ADIN_H: + case LTC2945_MAX_ADIN_H: + case LTC2945_MIN_ADIN_THRES_H: + case LTC2945_MAX_ADIN_THRES_H: + case LTC2945_MIN_ADIN_H: + return clamp_val(val, 0, LTC2945_ADIN_FULL_SCALE_MV); + case LTC2945_SENSE_H: + case LTC2945_MAX_SENSE_H: + case LTC2945_MIN_SENSE_H: + case LTC2945_MAX_SENSE_THRES_H: + case LTC2945_MIN_SENSE_THRES_H: + return clamp_val(val, 0, LTC2945_SENSE_FULL_SCALE_MA); + default: + /* + * This is unlikely to happen, and if it does, it should + * error out on the next call, we can't return negative here + */ + return 0; + } +} + static int ltc2945_val_to_reg(struct device *dev, u8 reg, unsigned long val) { @@ -257,6 +303,8 @@ static ssize_t ltc2945_value_store(struct device *dev, if (ret) return ret; + val = ltc2945_val_clamp(reg, val); + /* convert to register value, then clamp and write result */ regval = ltc2945_val_to_reg(dev, reg, val); if (is_power_reg(reg)) { -- 2.17.1