Currently, the driver does only support a custom sysfs
to allow userspace to read the fan speed.
Add support for the standard hwmon interface so users
can read the fan speed with standard tools like "sensors".
Compile-tested only.
Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
---
Changes since v1:
- fix undefined reference error
- fix fan speed validation
- coding style fixes
- clarify that the changes are compile-tested only
- add hwmon maintainers to cc list
The changes will be tested by Mikael Lund Jepsen from Danelec and
should be merged only after those tests.
---
drivers/acpi/Makefile | 1 +
drivers/acpi/fan.h | 9 +++++
drivers/acpi/fan_core.c | 4 ++
drivers/acpi/fan_hwmon.c | 83 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 97 insertions(+)
create mode 100644 drivers/acpi/fan_hwmon.c
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index d69d5444acdb..c272ab2c93b9 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -83,6 +83,7 @@ obj-$(CONFIG_ACPI_TINY_POWER_BUTTON) += tiny-power-button.o
obj-$(CONFIG_ACPI_FAN) += fan.o
fan-objs := fan_core.o
fan-objs += fan_attr.o
+fan-$(CONFIG_HWMON) += fan_hwmon.o
obj-$(CONFIG_ACPI_VIDEO) += video.o
obj-$(CONFIG_ACPI_TAD) += acpi_tad.o
diff --git a/drivers/acpi/fan.h b/drivers/acpi/fan.h
index e7b4b4e4a55e..97863bdb6303 100644
--- a/drivers/acpi/fan.h
+++ b/drivers/acpi/fan.h
@@ -10,6 +10,8 @@
#ifndef _ACPI_FAN_H_
#define _ACPI_FAN_H_
+#include <linux/kconfig.h>
+
#define ACPI_FAN_DEVICE_IDS \
{"INT3404", }, /* Fan */ \
{"INTC1044", }, /* Fan for Tiger Lake generation */ \
@@ -56,4 +58,11 @@ struct acpi_fan {
int acpi_fan_get_fst(struct acpi_device *device, struct acpi_fan_fst *fst);
int acpi_fan_create_attributes(struct acpi_device *device);
void acpi_fan_delete_attributes(struct acpi_device *device);
+
+#if IS_REACHABLE(CONFIG_HWMON)
+int devm_acpi_fan_create_hwmon(struct acpi_device *device);
+#else
+static inline int devm_acpi_fan_create_hwmon(struct acpi_device *device) { return 0; };
+#endif
+
#endif
diff --git a/drivers/acpi/fan_core.c b/drivers/acpi/fan_core.c
index ff72e4ef8738..7cea4495f19b 100644
--- a/drivers/acpi/fan_core.c
+++ b/drivers/acpi/fan_core.c
@@ -336,6 +336,10 @@ static int acpi_fan_probe(struct platform_device *pdev)
if (result)
return result;
+ result = devm_acpi_fan_create_hwmon(device);
+ if (result)
+ return result;
+
result = acpi_fan_create_attributes(device);
if (result)
return result;
diff --git a/drivers/acpi/fan_hwmon.c b/drivers/acpi/fan_hwmon.c
new file mode 100644
index 000000000000..b01055432ded
--- /dev/null
+++ b/drivers/acpi/fan_hwmon.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * fan_hwmon.c - hwmon interface for the ACPI Fan driver
+ *
+ * Copyright (C) 2024 Armin Wolf <W_Armin@xxxxxx>
+ */
+
+#include <linux/acpi.h>
+#include <linux/hwmon.h>
+#include <linux/limits.h>
+
+#include "fan.h"
+
+/* Returned when the ACPI fan does not support speed reporting */
+#define FAN_SPEED_UNAVAILABLE 0xffffffff
+
+static umode_t acpi_fan_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
+ int channel)
+{
+ return 0444;
+}
+
+static int acpi_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
+ long *val)
+{
+ struct acpi_device *adev = dev_get_drvdata(dev);
+ struct acpi_fan_fst fst;
+ int ret;
+
+ switch (type) {
+ case hwmon_fan:
+ ret = acpi_fan_get_fst(adev, &fst);
+ if (ret < 0)
+ return ret;
+
+ switch (attr) {
+ case hwmon_fan_input:
+ if (fst.speed == FAN_SPEED_UNAVAILABLE)
+ return -ENODATA;
+
+ if (fst.speed > LONG_MAX)
+ return -EOVERFLOW;
+
+ *val = fst.speed;
+ return 0;
+ case hwmon_fan_fault:
+ *val = (fst.speed == FAN_SPEED_UNAVAILABLE);
+ return 0;
+ default:
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+
+ return -EOPNOTSUPP;
+}
+
+static const struct hwmon_ops acpi_fan_ops = {
+ .is_visible = acpi_fan_is_visible,
+ .read = acpi_fan_read,
+};
+
+static const struct hwmon_channel_info * const acpi_fan_info[] = {
+ HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_FAULT),
+ NULL
+};
+
+static const struct hwmon_chip_info acpi_fan_chip_info = {
+ .ops = &acpi_fan_ops,
+ .info = acpi_fan_info,
+};
+
+int devm_acpi_fan_create_hwmon(struct acpi_device *device)
+{
+ struct device *hdev;
+
+ hdev = devm_hwmon_device_register_with_info(&device->dev, "acpi_fan", device,
+ &acpi_fan_chip_info, NULL);
+
+ return PTR_ERR_OR_ZERO(hdev);
+}
--
2.39.2
