linux-kernel - [PATCH 4/4] hwmon: emc2305: Set initial PWM minimum value during probe based on thermal state

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Message-Id: <20250603113125.3175103-5-florin.leotescu@oss.nxp.com>
Date: Tue,  3 Jun 2025 14:31:25 +0300
From: florin.leotescu@....nxp.com
To: Jean Delvare <jdelvare@...e.com>,
	Guenter Roeck <linux@...ck-us.net>,
	Florin Leotescu <florin.leotescu@....com>,
	linux-hwmon@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: viorel.suman@....com,
	carlos.song@....com,
	daniel.baluta@....com,
	linux-arm-kernel@...ts.infradead.org,
	imx@...ts.linux.dev,
	festevam@...il.com
Subject: [PATCH 4/4] hwmon: emc2305: Set initial PWM minimum value during probe based on thermal state

From: Florin Leotescu <florin.leotescu@....com>

Prevent the PWM value from being set to minimum when thermal zone
temperature exceeds any trip point during driver probe. Otherwise, the
PWM fan speed will remains at minimum speed and not respond to
temperature changes.

Signed-off-by: Florin Leotescu <florin.leotescu@....com>
---
 drivers/hwmon/emc2305.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/emc2305.c b/drivers/hwmon/emc2305.c
index db65c3177f29..60809289f816 100644
--- a/drivers/hwmon/emc2305.c
+++ b/drivers/hwmon/emc2305.c
@@ -317,6 +317,12 @@ static int emc2305_set_single_tz(struct device *dev, struct device_node *fan_nod
 		dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]);
 		return PTR_ERR(data->cdev_data[cdev_idx].cdev);
 	}
+
+	if (data->cdev_data[cdev_idx].cur_state > 0)
+		/* Update pwm when temperature is above trips */
+		pwm = EMC2305_PWM_STATE2DUTY(data->cdev_data[cdev_idx].cur_state,
+					     data->max_state, EMC2305_FAN_MAX);
+
 	/* Set minimal PWM speed. */
 	if (data->pwm_separate) {
 		ret = emc2305_set_pwm(dev, pwm, cdev_idx);
@@ -330,10 +336,10 @@ static int emc2305_set_single_tz(struct device *dev, struct device_node *fan_nod
 		}
 	}
 	data->cdev_data[cdev_idx].cur_state =
-		EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,
+		EMC2305_PWM_DUTY2STATE(pwm, data->max_state,
 				       EMC2305_FAN_MAX);
 	data->cdev_data[cdev_idx].last_hwmon_state =
-		EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,
+		EMC2305_PWM_DUTY2STATE(pwm, data->max_state,
 				       EMC2305_FAN_MAX);
 	return 0;
 }
-- 
2.34.1