[PATCH] hwmon: (scmi) Enable sensors to assure they can be read

[PATCH] hwmon: (scmi) Enable sensors to assure they can be read

[Marek Vasut]

The SCMI specification states that SENSOR_CONFIG_SET is used to
enable/disable the sensors. The sensors can be disabled by default,
which is the case at least on NXP i.MX95. Explicitly trigger the
SENSOR_CONFIG_SET to enable the sensors, otherwise sensor read may
fail and won't return valid data.

Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
---
Cc: Cristian Marussi <cristian.marussi@arm.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: arm-scmi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-hwmon@vger.kernel.org
---
 drivers/hwmon/scmi-hwmon.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/hwmon/scmi-hwmon.c b/drivers/hwmon/scmi-hwmon.c
index 364199b332c0a..eec223d174c07 100644
--- a/drivers/hwmon/scmi-hwmon.c
+++ b/drivers/hwmon/scmi-hwmon.c
@@ -240,6 +240,8 @@ static int scmi_hwmon_probe(struct scmi_device *sdev)
 	const struct hwmon_channel_info **ptr_scmi_ci;
 	const struct scmi_handle *handle = sdev->handle;
 	struct scmi_protocol_handle *ph;
+	u32 sensor_config = FIELD_PREP(SCMI_SENS_CFG_SENSOR_ENABLED_MASK,
+				       SCMI_SENS_CFG_SENSOR_ENABLE);
 
 	if (!handle)
 		return -ENODEV;
@@ -339,6 +341,13 @@ static int scmi_hwmon_probe(struct scmi_device *sdev)
 		if (!sensor)
 			continue;
 
+		ret = sensor_ops->config_set(ph, i, sensor_config);
+		if (ret) {
+			dev_err(dev, "Error enabling sensor %s. err=%d\n",
+				sensor->name, ret);
+			continue;
+		}
+
 		/*
 		 * Warn on any misconfiguration related to thermal zones but
 		 * bail out of probing only on memory errors.
-- 
2.51.0

Re: [PATCH] hwmon: (scmi) Enable sensors to assure they can be read

[Guenter Roeck]

On Wed, Oct 15, 2025 at 01:49:28PM +0200, Marek Vasut wrote:
> The SCMI specification states that SENSOR_CONFIG_SET is used to
> enable/disable the sensors. The sensors can be disabled by default,
> which is the case at least on NXP i.MX95. Explicitly trigger the
> SENSOR_CONFIG_SET to enable the sensors, otherwise sensor read may
> fail and won't return valid data.
> 
> Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>

Applied.

Thanks,
Guenter