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[78.94.0.51]) by smtp.gmail.com with ESMTPSA id h17-20020adff4d1000000b0031c52e81490sm1511297wrp.72.2023.11.03.03.31.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Nov 2023 03:31:42 -0700 (PDT) From: Alexander Hansen To: Jean Delvare , Guenter Roeck , Joel Stanley , Andrew Jeffery Cc: Loic Prylli , Alexander Hansen , linux-hwmon@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH v1 1/1] hwmon: (aspeed-pwm-tacho) mutex for tach reading Date: Fri, 3 Nov 2023 11:30:55 +0100 Message-ID: <121d888762a1232ef403cf35230ccf7b3887083a.1699007401.git.alexander.hansen@9elements.com> X-Mailer: git-send-email 2.42.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org From: Loic Prylli the ASPEED_PTCR_RESULT Register can only hold the result for a single fan input. Adding a mutex to protect the register until the reading is done. Signed-off-by: Loic Prylli Signed-off-by: Alexander Hansen --- drivers/hwmon/aspeed-pwm-tacho.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c index 997df4b40509..b2ae2176f11f 100644 --- a/drivers/hwmon/aspeed-pwm-tacho.c +++ b/drivers/hwmon/aspeed-pwm-tacho.c @@ -193,6 +193,8 @@ struct aspeed_pwm_tacho_data { u8 fan_tach_ch_source[16]; struct aspeed_cooling_device *cdev[8]; const struct attribute_group *groups[3]; + /* protects access to shared ASPEED_PTCR_RESULT */ + struct mutex tach_lock; }; enum type { TYPEM, TYPEN, TYPEO }; @@ -527,6 +529,8 @@ static int aspeed_get_fan_tach_ch_rpm(struct aspeed_pwm_tacho_data *priv, u8 fan_tach_ch_source, type, mode, both; int ret; + mutex_lock(&priv->tach_lock); + regmap_write(priv->regmap, ASPEED_PTCR_TRIGGER, 0); regmap_write(priv->regmap, ASPEED_PTCR_TRIGGER, 0x1 << fan_tach_ch); @@ -544,6 +548,8 @@ static int aspeed_get_fan_tach_ch_rpm(struct aspeed_pwm_tacho_data *priv, ASPEED_RPM_STATUS_SLEEP_USEC, usec); + mutex_unlock(&priv->tach_lock); + /* return -ETIMEDOUT if we didn't get an answer. */ if (ret) return ret; @@ -903,6 +909,7 @@ static int aspeed_pwm_tacho_probe(struct platform_device *pdev) priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; + mutex_init(&priv->tach_lock); priv->regmap = devm_regmap_init(dev, NULL, (__force void *)regs, &aspeed_pwm_tacho_regmap_config); if (IS_ERR(priv->regmap))