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From: Stanislav Aleksandrov <lightofmysoul@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Nurettin Bolucu <Nurettin.Bolucu@analog.com>,
	 linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org,
	 Stanislav Aleksandrov <lightofmysoul@gmail.com>
Subject: [PATCH 2/3] hwmon: (max31760) Leave standby mode at probe
Date: Sun, 08 Nov 2026 03:59:54 +0000	[thread overview]
Message-ID: <20261108-max31760-fixes-v1-2-a61450463059@gmail.com> (raw)
In-Reply-To: <20261108-max31760-fixes-v1-0-a61450463059@gmail.com>

The driver never clears the standby bit (CR2_STBY) during probe.
While max31760_resume() clears this bit on resume, probe only
configured CR2_ALERTS.

If the chip was left in standby (for example, by boot firmware or a
previously running OS before a warm reboot), it remains in standby:
temperature sensing, fan speed counting, and PWM output are halted.
This occurs on the Samsung Galaxy XR, where the bootloader places the
chip in standby during boot.

Clear CR2_STBY alongside setting CR2_ALERTS in probe.

Fixes: 38b04ad02d0d ("drivers: hwmon: Add max31760 fan speed controller driver")
Signed-off-by: Stanislav Aleksandrov <lightofmysoul@gmail.com>
---
 drivers/hwmon/max31760.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/max31760.c b/drivers/hwmon/max31760.c
index e3d86dc4257e..e967555a21af 100644
--- a/drivers/hwmon/max31760.c
+++ b/drivers/hwmon/max31760.c
@@ -533,8 +533,9 @@ static int max31760_probe(struct i2c_client *client)
 
 	dev_set_drvdata(dev, state);
 
-	/* Set alert output to comparator mode */
-	ret = regmap_set_bits(state->regmap, REG_CR2, CR2_ALERTS);
+	/* Leave standby mode, set alert output to comparator mode */
+	ret = regmap_update_bits(state->regmap, REG_CR2, CR2_STBY | CR2_ALERTS,
+				 CR2_ALERTS);
 	if (ret)
 		return dev_err_probe(dev, ret, "cannot write register\n");
 

-- 
2.55.0


  parent reply	other threads:[~2026-11-08  4:00 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-08  3:59 [PATCH 0/3] hwmon: (max31760) Fix local limits, standby and the initial fan speed Stanislav Aleksandrov
2026-11-08  3:59 ` [PATCH 1/3] hwmon: (max31760) Fix the local temperature limit registers Stanislav Aleksandrov
2026-11-08  3:59 ` Stanislav Aleksandrov [this message]
2026-11-08  3:59 ` [PATCH 3/3] hwmon: (max31760) Report 0 RPM before the first fan speed measurement Stanislav Aleksandrov

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