linux-kernel - [PATCH 1/2] Revert "thermal/drivers/mediatek: Add delay after thermal banks initialization"

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Date:   Wed, 19 Apr 2023 08:11:45 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     rafael@...nel.org
Cc:     daniel.lezcano@...aro.org, amitk@...nel.org, rui.zhang@...el.com,
        matthias.bgg@...il.com, angelogioacchino.delregno@...labora.com,
        aouledameur@...libre.com, bchihi@...libre.com,
        daniel@...rotopia.org, ye.xingchen@....com.cn, hsinyi@...omium.org,
        michael.kao@...iatek.com, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        "kernelci.org bot" <bot@...nelci.org>
Subject: [PATCH 1/2] Revert "thermal/drivers/mediatek: Add delay after thermal banks initialization"

Some more testing revealed that this commit introduces a regression on some
MT8173 Chromebooks and at least on one MT6795 Sony Xperia M5 smartphone due
to the delay being apparently variable and machine specific.

Another solution would be to delay for a bit more (~70ms) but this is not
feasible for two reasons: first of all, we're adding an even bigger delay
in a probe function; second, some machines need less, some may need even
more, making the msleep at probe solution highly suboptimal.

This reverts commit 10debf8c2da8011c8009dd4b3f6d0ab85891c81b.

Fixes: 10debf8c2da8 ("thermal/drivers/mediatek: Add delay after thermal banks initialization")
Reported-by: "kernelci.org bot" <bot@...nelci.org>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
 drivers/thermal/mediatek/auxadc_thermal.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/thermal/mediatek/auxadc_thermal.c b/drivers/thermal/mediatek/auxadc_thermal.c
index b6bb9eaafb74..3c959a827451 100644
--- a/drivers/thermal/mediatek/auxadc_thermal.c
+++ b/drivers/thermal/mediatek/auxadc_thermal.c
@@ -816,6 +816,14 @@ static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
 			mt, conf->bank_data[bank->id].sensors[i], raw);
 
 
+		/*
+		 * The first read of a sensor often contains very high bogus
+		 * temperature value. Filter these out so that the system does
+		 * not immediately shut down.
+		 */
+		if (temp > 200000)
+			temp = 0;
+
 		if (temp > max)
 			max = temp;
 	}
@@ -1273,9 +1281,6 @@ static int mtk_thermal_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, mt);
 
-	/* Delay for thermal banks to be ready */
-	msleep(30);
-
 	tzdev = devm_thermal_of_zone_register(&pdev->dev, 0, mt,
 					      &mtk_thermal_ops);
 	if (IS_ERR(tzdev)) {
-- 
2.40.0