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[87.0.193.30]) by smtp.googlemail.com with ESMTPSA id k6sm105954edv.77.2021.09.07.14.26.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Sep 2021 14:26:05 -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 v2 2/2] drivers: thermal: tsens: add timeout to get_tem_tsens_valid Date: Tue, 7 Sep 2021 23:25:43 +0200 Message-Id: <20210907212543.20220-2-ansuelsmth@gmail.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210907212543.20220-1-ansuelsmth@gmail.com> References: <20210907212543.20220-1-ansuelsmth@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@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. While at it also rework the function to improve readability. Signed-off-by: Ansuel Smith --- drivers/thermal/qcom/tsens.c | 40 +++++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 14 deletions(-) diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c index b1162e566a70..1ff244176beb 100644 --- a/drivers/thermal/qcom/tsens.c +++ b/drivers/thermal/qcom/tsens.c @@ -599,26 +599,38 @@ 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; /* VER_0 doesn't have VALID bit */ - if (tsens_version(priv) >= VER_0_1) { + if (tsens_version(priv) == VER_0) + goto get_temp; + + ret = regmap_field_read(priv->rf[valid_idx], &valid); + if (ret || valid) + goto check_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 (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 (ret) - return ret; - } - } + if (ret || valid) + goto check_valid; + } while (time_before(jiffies, timeout)); + + return -ETIMEDOUT; + +check_valid: + /* Check ret of valid bit read */ + if (ret) + return ret; +get_temp: /* Valid bit is set, OK to read the temperature */ *temp = tsens_hw_to_mC(s, temp_idx);