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[79.19.158.155]) by smtp.googlemail.com with ESMTPSA id j13sm3165986edt.72.2021.09.05.10.47.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 05 Sep 2021 10:47:33 -0700 (PDT) From: Ansuel Smith To: Andy Gross , Bjorn Andersson , Amit Kucheria , Thara Gopinath , Zhang Rui , Daniel Lezcano , linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ansuel Smith Subject: [PATCH 2/2] drivers: thermal: tsens: add timeout to get_tem_tsens_valid Date: Sun, 5 Sep 2021 19:47:08 +0200 Message-Id: <20210905174708.4605-2-ansuelsmth@gmail.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210905174708.4605-1-ansuelsmth@gmail.com> References: <20210905174708.4605-1-ansuelsmth@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The function can loop and lock the system if for whatever reason the bit for the target sensor is NEVER valid. This is the case if a sensor is disabled by the factory and the valid bit is never reported as actually valid. Add a timeout check and exit if a timeout occurs. As this is a very rare condition, handle the timeout only if the first read fails. Signed-off-by: Ansuel Smith --- drivers/thermal/qcom/tsens.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c index b1162e566a70..38afde1a599f 100644 --- a/drivers/thermal/qcom/tsens.c +++ b/drivers/thermal/qcom/tsens.c @@ -599,6 +599,7 @@ int get_temp_tsens_valid(const struct tsens_sensor *s, int *temp) int hw_id = s->hw_id; u32 temp_idx = LAST_TEMP_0 + hw_id; u32 valid_idx = VALID_0 + hw_id; + unsigned long timeout; u32 valid; int ret; @@ -607,13 +608,21 @@ int get_temp_tsens_valid(const struct tsens_sensor *s, int *temp) ret = regmap_field_read(priv->rf[valid_idx], &valid); if (ret) return ret; - while (!valid) { - /* Valid bit is 0 for 6 AHB clock cycles. - * At 19.2MHz, 1 AHB clock is ~60ns. - * We should enter this loop very, very rarely. - */ - ndelay(400); - ret = regmap_field_read(priv->rf[valid_idx], &valid); + + if (!valid) { + timeout = jiffies + msecs_to_jiffies(20); + + do { + /* Valid bit is 0 for 6 AHB clock cycles. + * At 19.2MHz, 1 AHB clock is ~60ns. + * We should enter this loop very, very rarely. + */ + ndelay(400); + ret = regmap_field_read(priv->rf[valid_idx], &valid); + if (valid || ret) + break; + } while (!(ret = time_after_eq(jiffies, timeout))); + if (ret) return ret; } -- 2.32.0