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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 0C256C11F7B for ; Mon, 12 Jul 2021 07:29:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 02D746108B for ; Mon, 12 Jul 2021 07:29:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344482AbhGLHbw (ORCPT ); Mon, 12 Jul 2021 03:31:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:39382 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239846AbhGLHDh (ORCPT ); Mon, 12 Jul 2021 03:03:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8F98A610E5; Mon, 12 Jul 2021 07:00:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626073249; bh=eTrAhuEnhf1jwS563QR50Re9w5Dovg9QzGL1lL+ozPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=So2OtvuSLZ9RP/LEiNV6kIgSJFvjPj5Br+7R5D8Uc8VEanpqxy3lo0U4F3S/cGoxZ oJLIgPaeVEslzlYmSMt9Uv8O+M1JqlXgxxH4Z++uIE+OSvKQKdaM4gQMSqh7wSxaht qOTfF2D7TU5MRuNMVHUUyLojCKS3HUWDxcHI6eDU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Jan=20Kundr=C3=A1t?= , =?UTF-8?q?V=C3=A1clav=20Kubern=C3=A1t?= , Guenter Roeck , Sasha Levin Subject: [PATCH 5.12 178/700] hwmon: (max31790) Fix pwmX_enable attributes Date: Mon, 12 Jul 2021 08:04:21 +0200 Message-Id: <20210712060951.682995314@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060924.797321836@linuxfoundation.org> References: <20210712060924.797321836@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Guenter Roeck [ Upstream commit 148c847c9e5a54b99850617bf9c143af9a344f92 ] pwmX_enable supports three possible values: 0: Fan control disabled. Duty cycle is fixed to 0% 1: Fan control enabled, pwm mode. Duty cycle is determined by values written into Target Duty Cycle registers. 2: Fan control enabled, rpm mode Duty cycle is adjusted such that fan speed matches the values in Target Count registers The current code does not do this; instead, it mixes pwm control configuration with fan speed monitoring configuration. Worse, it reports that pwm control would be disabled (pwmX_enable==0) when it is in fact enabled in pwm mode. Part of the problem may be that the chip sets the "TACH input enable" bit on its own whenever the mode bit is set to RPM mode, but that doesn't mean that "TACH input enable" accurately reflects the pwm mode. Fix it up and only handle pwm control with the pwmX_enable attributes. In the documentation, clarify that disabling pwm control (pwmX_enable=0) sets the pwm duty cycle to 0%. In the code, explain why TACH_INPUT_EN is set together with RPM_MODE. While at it, only update the configuration register if the configuration has changed, and only update the cached configuration if updating the chip configuration was successful. Cc: Jan Kundrát Cc: Václav Kubernát Signed-off-by: Guenter Roeck Tested-by: Václav Kubernát Reviewed-by: Jan Kundrát Link: https://lore.kernel.org/r/20210526154022.3223012-4-linux@roeck-us.net Signed-off-by: Sasha Levin --- Documentation/hwmon/max31790.rst | 2 +- drivers/hwmon/max31790.c | 41 ++++++++++++++++++++------------ 2 files changed, 27 insertions(+), 16 deletions(-) diff --git a/Documentation/hwmon/max31790.rst b/Documentation/hwmon/max31790.rst index 54ff0f49e28f..7b097c3b9b90 100644 --- a/Documentation/hwmon/max31790.rst +++ b/Documentation/hwmon/max31790.rst @@ -38,7 +38,7 @@ Sysfs entries fan[1-12]_input RO fan tachometer speed in RPM fan[1-12]_fault RO fan experienced fault fan[1-6]_target RW desired fan speed in RPM -pwm[1-6]_enable RW regulator mode, 0=disabled, 1=manual mode, 2=rpm mode +pwm[1-6]_enable RW regulator mode, 0=disabled (duty cycle=0%), 1=manual mode, 2=rpm mode pwm[1-6] RW read: current pwm duty cycle, write: target pwm duty cycle (0-255) ================== === ======================================================= diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c index 8ad7a45bfe68..76aa96f5b984 100644 --- a/drivers/hwmon/max31790.c +++ b/drivers/hwmon/max31790.c @@ -27,6 +27,7 @@ /* Fan Config register bits */ #define MAX31790_FAN_CFG_RPM_MODE 0x80 +#define MAX31790_FAN_CFG_CTRL_MON 0x10 #define MAX31790_FAN_CFG_TACH_INPUT_EN 0x08 #define MAX31790_FAN_CFG_TACH_INPUT 0x01 @@ -271,12 +272,12 @@ static int max31790_read_pwm(struct device *dev, u32 attr, int channel, *val = data->pwm[channel] >> 8; return 0; case hwmon_pwm_enable: - if (fan_config & MAX31790_FAN_CFG_RPM_MODE) + if (fan_config & MAX31790_FAN_CFG_CTRL_MON) + *val = 0; + else if (fan_config & MAX31790_FAN_CFG_RPM_MODE) *val = 2; - else if (fan_config & MAX31790_FAN_CFG_TACH_INPUT_EN) - *val = 1; else - *val = 0; + *val = 1; return 0; default: return -EOPNOTSUPP; @@ -307,23 +308,33 @@ static int max31790_write_pwm(struct device *dev, u32 attr, int channel, case hwmon_pwm_enable: fan_config = data->fan_config[channel]; if (val == 0) { - fan_config &= ~(MAX31790_FAN_CFG_TACH_INPUT_EN | - MAX31790_FAN_CFG_RPM_MODE); + fan_config |= MAX31790_FAN_CFG_CTRL_MON; + /* + * Disable RPM mode; otherwise disabling fan speed + * monitoring is not possible. + */ + fan_config &= ~MAX31790_FAN_CFG_RPM_MODE; } else if (val == 1) { - fan_config = (fan_config | - MAX31790_FAN_CFG_TACH_INPUT_EN) & - ~MAX31790_FAN_CFG_RPM_MODE; + fan_config &= ~(MAX31790_FAN_CFG_CTRL_MON | MAX31790_FAN_CFG_RPM_MODE); } else if (val == 2) { - fan_config |= MAX31790_FAN_CFG_TACH_INPUT_EN | - MAX31790_FAN_CFG_RPM_MODE; + fan_config &= ~MAX31790_FAN_CFG_CTRL_MON; + /* + * The chip sets MAX31790_FAN_CFG_TACH_INPUT_EN on its + * own if MAX31790_FAN_CFG_RPM_MODE is set. + * Do it here as well to reflect the actual register + * value in the cache. + */ + fan_config |= (MAX31790_FAN_CFG_RPM_MODE | MAX31790_FAN_CFG_TACH_INPUT_EN); } else { err = -EINVAL; break; } - data->fan_config[channel] = fan_config; - err = i2c_smbus_write_byte_data(client, - MAX31790_REG_FAN_CONFIG(channel), - fan_config); + if (fan_config != data->fan_config[channel]) { + err = i2c_smbus_write_byte_data(client, MAX31790_REG_FAN_CONFIG(channel), + fan_config); + if (!err) + data->fan_config[channel] = fan_config; + } break; default: err = -EOPNOTSUPP; -- 2.30.2