Third version of a hwmon driver to monitor the fan's rpm on Microsoft
Surface devices, originally submitted in [1], v2 at [2]. All changes since
v2 are incorporating feedback, cleaning up and simplifying the module.
Changes in v3:
- Removed type and attr checks in read and is_visible.
- Removed assigning sdev to ssam_device drvdata.
- Propagate return from __ssam_fan_rpm_get.
- Renamed hwmon chip name from 'fan' to 'surface_fan'.
- Removed unnecessary platform_device header.
Changes in v2:
- Removed all unsupported sysfs attributes from the hwmon driver, leaving
the fan input as the only supported attribute.
[1] https://lore.kernel.org/linux-hwmon/[email protected]/T/
[2] https://lore.kernel.org/linux-hwmon/[email protected]/T/
Ivor Wanders (2):
platform/surface: aggregator_registry: add entry for fan speed
hwmon: add fan speed monitoring driver for Surface devices
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/surface_fan.rst | 25 +++++
MAINTAINERS | 8 ++
drivers/hwmon/Kconfig | 13 +++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/surface_fan.c | 93 +++++++++++++++++++
.../surface/surface_aggregator_registry.c | 7 ++
7 files changed, 148 insertions(+)
create mode 100644 Documentation/hwmon/surface_fan.rst
create mode 100644 drivers/hwmon/surface_fan.c
--
2.17.1
Add an entry for the fan speed function.
Add this new entry to the Surface Pro 9 group.
Signed-off-by: Ivor Wanders <[email protected]>
Link: https://github.com/linux-surface/kernel/pull/144
Reviewed-by: Maximilian Luz <[email protected]>
---
Changes in v3:
- No changes in this patch.
Changes in v2:
- No changes in this patch.
---
drivers/platform/surface/surface_aggregator_registry.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index 530db4db7..b0db25886 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -74,6 +74,12 @@ static const struct software_node ssam_node_tmp_pprof = {
.parent = &ssam_node_root,
};
+/* Fan speed function. */
+static const struct software_node ssam_node_fan_speed = {
+ .name = "ssam:01:05:01:01:01",
+ .parent = &ssam_node_root,
+};
+
/* Tablet-mode switch via KIP subsystem. */
static const struct software_node ssam_node_kip_tablet_switch = {
.name = "ssam:01:0e:01:00:01",
@@ -319,6 +325,7 @@ static const struct software_node *ssam_node_group_sp9[] = {
&ssam_node_bat_ac,
&ssam_node_bat_main,
&ssam_node_tmp_pprof,
+ &ssam_node_fan_speed,
&ssam_node_pos_tablet_switch,
&ssam_node_hid_kip_keyboard,
&ssam_node_hid_kip_penstash,
--
2.17.1
Adds a driver that provides read only access to the fan speed for Microsoft
Surface Pro devices. The fan speed is always regulated by the EC and cannot
be influenced directly.
Signed-off-by: Ivor Wanders <[email protected]>
Link: https://github.com/linux-surface/kernel/pull/144
---
Changes in v3:
- Removed type and attr checks in read and is_visible.
- Removed assigning sdev to ssam_device drvdata.
- Propagate return from __ssam_fan_rpm_get.
- Renamed hwmon chip name from 'fan' to 'surface_fan'.
- Removed unnecessary platform_device header.
Changes in v2:
- Removed all sysfs attributes except fan1_input. Simplified code
and updated documentation accordingly.
---
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/surface_fan.rst | 25 ++++++++
MAINTAINERS | 8 +++
drivers/hwmon/Kconfig | 13 ++++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/surface_fan.c | 93 +++++++++++++++++++++++++++++
6 files changed, 141 insertions(+)
create mode 100644 Documentation/hwmon/surface_fan.rst
create mode 100644 drivers/hwmon/surface_fan.c
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 042e1cf95..4dfb3b9bd 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -202,6 +202,7 @@ Hardware Monitoring Kernel Drivers
smsc47m1
sparx5-temp
stpddc60
+ surface_fan
sy7636a-hwmon
tc654
tc74
diff --git a/Documentation/hwmon/surface_fan.rst b/Documentation/hwmon/surface_fan.rst
new file mode 100644
index 000000000..07942574c
--- /dev/null
+++ b/Documentation/hwmon/surface_fan.rst
@@ -0,0 +1,25 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver surface_fan
+=========================
+
+Supported Devices:
+
+ * Microsoft Surface Pro 9
+
+Author: Ivor Wanders <[email protected]>
+
+Description
+-----------
+
+This provides monitoring of the fan found in some Microsoft Surface Pro devices,
+like the Surface Pro 9. The fan is always controlled by the onboard controller.
+
+Sysfs interface
+---------------
+
+======================= ======= =========================================
+Name Perm Description
+======================= ======= =========================================
+``fan1_input`` RO Current fan speed in RPM.
+======================= ======= =========================================
diff --git a/MAINTAINERS b/MAINTAINERS
index 439cf523b..8e7870af3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14078,6 +14078,14 @@ F: Documentation/driver-api/surface_aggregator/clients/dtx.rst
F: drivers/platform/surface/surface_dtx.c
F: include/uapi/linux/surface_aggregator/dtx.h
+MICROSOFT SURFACE SENSOR FAN DRIVER
+M: Maximilian Luz <[email protected]>
+M: Ivor Wanders <[email protected]>
+L: [email protected]
+S: Maintained
+F: Documentation/hwmon/surface_fan.rst
+F: drivers/hwmon/surface_fan.c
+
MICROSOFT SURFACE GPE LID SUPPORT DRIVER
M: Maximilian Luz <[email protected]>
L: [email protected]
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 307477b8a..4b4d999af 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1965,6 +1965,19 @@ config SENSORS_SMM665
This driver can also be built as a module. If so, the module will
be called smm665.
+config SENSORS_SURFACE_FAN
+ tristate "Surface Fan Driver"
+ depends on SURFACE_AGGREGATOR
+ help
+ Driver that provides monitoring of the fan on Surface Pro devices that
+ have a fan, like the Surface Pro 9.
+
+ This makes the fan's current speed accessible through the hwmon
+ system. It does not provide control over the fan, the firmware is
+ responsible for that, this driver merely provides monitoring.
+
+ Select M or Y here, if you want to be able to read the fan's speed.
+
config SENSORS_ADC128D818
tristate "Texas Instruments ADC128D818"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 3f4b0fda0..5ae214c06 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -198,6 +198,7 @@ obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o
obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
obj-$(CONFIG_SENSORS_SPARX5) += sparx5-temp.o
obj-$(CONFIG_SENSORS_STTS751) += stts751.o
+obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o
obj-$(CONFIG_SENSORS_SY7636A) += sy7636a-hwmon.o
obj-$(CONFIG_SENSORS_AMC6821) += amc6821.o
obj-$(CONFIG_SENSORS_TC74) += tc74.o
diff --git a/drivers/hwmon/surface_fan.c b/drivers/hwmon/surface_fan.c
new file mode 100644
index 000000000..7c2e3ae3e
--- /dev/null
+++ b/drivers/hwmon/surface_fan.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Surface Fan driver for Surface System Aggregator Module. It provides access
+ * to the fan's rpm through the hwmon system.
+ *
+ * Copyright (C) 2023 Ivor Wanders <[email protected]>
+ */
+
+#include <linux/hwmon.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/surface_aggregator/device.h>
+#include <linux/types.h>
+
+// SSAM
+SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_fan_rpm_get, __le16, {
+ .target_category = SSAM_SSH_TC_FAN,
+ .command_id = 0x01,
+});
+
+// hwmon
+umode_t surface_fan_hwmon_is_visible(const void *drvdata,
+ enum hwmon_sensor_types type, u32 attr,
+ int channel)
+{
+ return 0444;
+}
+
+static int surface_fan_hwmon_read(struct device *dev,
+ enum hwmon_sensor_types type, u32 attr,
+ int channel, long *val)
+{
+ struct ssam_device *sdev = dev_get_drvdata(dev);
+ int ret;
+ __le16 value;
+
+ ret = __ssam_fan_rpm_get(sdev, &value);
+ if (ret)
+ return ret;
+
+ *val = le16_to_cpu(value);
+
+ return ret;
+}
+
+static const struct hwmon_channel_info *const surface_fan_info[] = {
+ HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
+ NULL
+};
+
+static const struct hwmon_ops surface_fan_hwmon_ops = {
+ .is_visible = surface_fan_hwmon_is_visible,
+ .read = surface_fan_hwmon_read,
+};
+
+static const struct hwmon_chip_info surface_fan_chip_info = {
+ .ops = &surface_fan_hwmon_ops,
+ .info = surface_fan_info,
+};
+
+static int surface_fan_probe(struct ssam_device *sdev)
+{
+ struct device *hdev;
+
+ hdev = devm_hwmon_device_register_with_info(&sdev->dev,
+ "surface_fan", sdev,
+ &surface_fan_chip_info,
+ NULL);
+ if (IS_ERR(hdev))
+ return PTR_ERR(hdev);
+
+ return 0;
+}
+
+static const struct ssam_device_id ssam_fan_match[] = {
+ { SSAM_SDEV(FAN, SAM, 0x01, 0x01) },
+ {},
+};
+MODULE_DEVICE_TABLE(ssam, ssam_fan_match);
+
+static struct ssam_device_driver surface_fan = {
+ .probe = surface_fan_probe,
+ .match_table = ssam_fan_match,
+ .driver = {
+ .name = "surface_fan",
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ },
+};
+module_ssam_device_driver(surface_fan);
+
+MODULE_AUTHOR("Ivor Wanders <[email protected]>");
+MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module");
+MODULE_LICENSE("GPL");
--
2.17.1
On 1/13/24 19:33, Ivor Wanders wrote:
> Adds a driver that provides read only access to the fan speed for Microsoft
> Surface Pro devices. The fan speed is always regulated by the EC and cannot
> be influenced directly.
>
> Signed-off-by: Ivor Wanders <[email protected]>
> Link: https://github.com/linux-surface/kernel/pull/144
The Surface related things look good to me. For those:
Reviewed-by: Maximilian Luz <[email protected]>
> ---
> Changes in v3:
> - Removed type and attr checks in read and is_visible.
> - Removed assigning sdev to ssam_device drvdata.
> - Propagate return from __ssam_fan_rpm_get.
> - Renamed hwmon chip name from 'fan' to 'surface_fan'.
> - Removed unnecessary platform_device header.
> Changes in v2:
> - Removed all sysfs attributes except fan1_input. Simplified code
> and updated documentation accordingly.
> ---
> Documentation/hwmon/index.rst | 1 +
> Documentation/hwmon/surface_fan.rst | 25 ++++++++
> MAINTAINERS | 8 +++
> drivers/hwmon/Kconfig | 13 ++++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/surface_fan.c | 93 +++++++++++++++++++++++++++++
> 6 files changed, 141 insertions(+)
> create mode 100644 Documentation/hwmon/surface_fan.rst
> create mode 100644 drivers/hwmon/surface_fan.c
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 042e1cf95..4dfb3b9bd 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -202,6 +202,7 @@ Hardware Monitoring Kernel Drivers
> smsc47m1
> sparx5-temp
> stpddc60
> + surface_fan
> sy7636a-hwmon
> tc654
> tc74
> diff --git a/Documentation/hwmon/surface_fan.rst b/Documentation/hwmon/surface_fan.rst
> new file mode 100644
> index 000000000..07942574c
> --- /dev/null
> +++ b/Documentation/hwmon/surface_fan.rst
> @@ -0,0 +1,25 @@
> +.. SPDX-License-Identifier: GPL-2.0-or-later
> +
> +Kernel driver surface_fan
> +=========================
> +
> +Supported Devices:
> +
> + * Microsoft Surface Pro 9
> +
> +Author: Ivor Wanders <[email protected]>
> +
> +Description
> +-----------
> +
> +This provides monitoring of the fan found in some Microsoft Surface Pro devices,
> +like the Surface Pro 9. The fan is always controlled by the onboard controller.
> +
> +Sysfs interface
> +---------------
> +
> +======================= ======= =========================================
> +Name Perm Description
> +======================= ======= =========================================
> +``fan1_input`` RO Current fan speed in RPM.
> +======================= ======= =========================================
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 439cf523b..8e7870af3 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14078,6 +14078,14 @@ F: Documentation/driver-api/surface_aggregator/clients/dtx.rst
> F: drivers/platform/surface/surface_dtx.c
> F: include/uapi/linux/surface_aggregator/dtx.h
>
> +MICROSOFT SURFACE SENSOR FAN DRIVER
> +M: Maximilian Luz <[email protected]>
> +M: Ivor Wanders <[email protected]>
> +L: [email protected]
> +S: Maintained
> +F: Documentation/hwmon/surface_fan.rst
> +F: drivers/hwmon/surface_fan.c
> +
> MICROSOFT SURFACE GPE LID SUPPORT DRIVER
> M: Maximilian Luz <[email protected]>
> L: [email protected]
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 307477b8a..4b4d999af 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1965,6 +1965,19 @@ config SENSORS_SMM665
> This driver can also be built as a module. If so, the module will
> be called smm665.
>
> +config SENSORS_SURFACE_FAN
> + tristate "Surface Fan Driver"
> + depends on SURFACE_AGGREGATOR
> + help
> + Driver that provides monitoring of the fan on Surface Pro devices that
> + have a fan, like the Surface Pro 9.
> +
> + This makes the fan's current speed accessible through the hwmon
> + system. It does not provide control over the fan, the firmware is
> + responsible for that, this driver merely provides monitoring.
> +
> + Select M or Y here, if you want to be able to read the fan's speed.
> +
> config SENSORS_ADC128D818
> tristate "Texas Instruments ADC128D818"
> depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 3f4b0fda0..5ae214c06 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -198,6 +198,7 @@ obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o
> obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
> obj-$(CONFIG_SENSORS_SPARX5) += sparx5-temp.o
> obj-$(CONFIG_SENSORS_STTS751) += stts751.o
> +obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o
> obj-$(CONFIG_SENSORS_SY7636A) += sy7636a-hwmon.o
> obj-$(CONFIG_SENSORS_AMC6821) += amc6821.o
> obj-$(CONFIG_SENSORS_TC74) += tc74.o
> diff --git a/drivers/hwmon/surface_fan.c b/drivers/hwmon/surface_fan.c
> new file mode 100644
> index 000000000..7c2e3ae3e
> --- /dev/null
> +++ b/drivers/hwmon/surface_fan.c
> @@ -0,0 +1,93 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Surface Fan driver for Surface System Aggregator Module. It provides access
> + * to the fan's rpm through the hwmon system.
> + *
> + * Copyright (C) 2023 Ivor Wanders <[email protected]>
> + */
> +
> +#include <linux/hwmon.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/surface_aggregator/device.h>
> +#include <linux/types.h>
> +
> +// SSAM
> +SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_fan_rpm_get, __le16, {
> + .target_category = SSAM_SSH_TC_FAN,
> + .command_id = 0x01,
> +});
> +
> +// hwmon
> +umode_t surface_fan_hwmon_is_visible(const void *drvdata,
> + enum hwmon_sensor_types type, u32 attr,
> + int channel)
> +{
> + return 0444;
> +}
> +
> +static int surface_fan_hwmon_read(struct device *dev,
> + enum hwmon_sensor_types type, u32 attr,
> + int channel, long *val)
> +{
> + struct ssam_device *sdev = dev_get_drvdata(dev);
> + int ret;
> + __le16 value;
> +
> + ret = __ssam_fan_rpm_get(sdev, &value);
> + if (ret)
> + return ret;
> +
> + *val = le16_to_cpu(value);
> +
> + return ret;
> +}
> +
> +static const struct hwmon_channel_info *const surface_fan_info[] = {
> + HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
> + NULL
> +};
> +
> +static const struct hwmon_ops surface_fan_hwmon_ops = {
> + .is_visible = surface_fan_hwmon_is_visible,
> + .read = surface_fan_hwmon_read,
> +};
> +
> +static const struct hwmon_chip_info surface_fan_chip_info = {
> + .ops = &surface_fan_hwmon_ops,
> + .info = surface_fan_info,
> +};
> +
> +static int surface_fan_probe(struct ssam_device *sdev)
> +{
> + struct device *hdev;
> +
> + hdev = devm_hwmon_device_register_with_info(&sdev->dev,
> + "surface_fan", sdev,
> + &surface_fan_chip_info,
> + NULL);
> + if (IS_ERR(hdev))
> + return PTR_ERR(hdev);
> +
> + return 0;
> +}
> +
> +static const struct ssam_device_id ssam_fan_match[] = {
> + { SSAM_SDEV(FAN, SAM, 0x01, 0x01) },
> + {},
> +};
> +MODULE_DEVICE_TABLE(ssam, ssam_fan_match);
> +
> +static struct ssam_device_driver surface_fan = {
> + .probe = surface_fan_probe,
> + .match_table = ssam_fan_match,
> + .driver = {
> + .name = "surface_fan",
> + .probe_type = PROBE_PREFER_ASYNCHRONOUS,
> + },
> +};
> +module_ssam_device_driver(surface_fan);
> +
> +MODULE_AUTHOR("Ivor Wanders <[email protected]>");
> +MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module");
> +MODULE_LICENSE("GPL");
Am 13.01.24 um 19:33 schrieb Ivor Wanders:
> Adds a driver that provides read only access to the fan speed for Microsoft
> Surface Pro devices. The fan speed is always regulated by the EC and cannot
> be influenced directly.
>
> Signed-off-by: Ivor Wanders <[email protected]>
> Link: https://github.com/linux-surface/kernel/pull/144
> ---
> Changes in v3:
> - Removed type and attr checks in read and is_visible.
> - Removed assigning sdev to ssam_device drvdata.
> - Propagate return from __ssam_fan_rpm_get.
> - Renamed hwmon chip name from 'fan' to 'surface_fan'.
> - Removed unnecessary platform_device header.
> Changes in v2:
> - Removed all sysfs attributes except fan1_input. Simplified code
> and updated documentation accordingly.
> ---
> Documentation/hwmon/index.rst | 1 +
> Documentation/hwmon/surface_fan.rst | 25 ++++++++
> MAINTAINERS | 8 +++
> drivers/hwmon/Kconfig | 13 ++++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/surface_fan.c | 93 +++++++++++++++++++++++++++++
> 6 files changed, 141 insertions(+)
> create mode 100644 Documentation/hwmon/surface_fan.rst
> create mode 100644 drivers/hwmon/surface_fan.c
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 042e1cf95..4dfb3b9bd 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -202,6 +202,7 @@ Hardware Monitoring Kernel Drivers
> smsc47m1
> sparx5-temp
> stpddc60
> + surface_fan
> sy7636a-hwmon
> tc654
> tc74
> diff --git a/Documentation/hwmon/surface_fan.rst b/Documentation/hwmon/surface_fan.rst
> new file mode 100644
> index 000000000..07942574c
> --- /dev/null
> +++ b/Documentation/hwmon/surface_fan.rst
> @@ -0,0 +1,25 @@
> +.. SPDX-License-Identifier: GPL-2.0-or-later
> +
> +Kernel driver surface_fan
> +=========================
> +
> +Supported Devices:
> +
> + * Microsoft Surface Pro 9
> +
> +Author: Ivor Wanders <[email protected]>
> +
> +Description
> +-----------
> +
> +This provides monitoring of the fan found in some Microsoft Surface Pro devices,
> +like the Surface Pro 9. The fan is always controlled by the onboard controller.
> +
> +Sysfs interface
> +---------------
> +
> +======================= ======= =========================================
> +Name Perm Description
> +======================= ======= =========================================
> +``fan1_input`` RO Current fan speed in RPM.
> +======================= ======= =========================================
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 439cf523b..8e7870af3 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14078,6 +14078,14 @@ F: Documentation/driver-api/surface_aggregator/clients/dtx.rst
> F: drivers/platform/surface/surface_dtx.c
> F: include/uapi/linux/surface_aggregator/dtx.h
>
> +MICROSOFT SURFACE SENSOR FAN DRIVER
> +M: Maximilian Luz <[email protected]>
> +M: Ivor Wanders <[email protected]>
> +L: [email protected]
> +S: Maintained
> +F: Documentation/hwmon/surface_fan.rst
> +F: drivers/hwmon/surface_fan.c
> +
> MICROSOFT SURFACE GPE LID SUPPORT DRIVER
> M: Maximilian Luz <[email protected]>
> L: [email protected]
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 307477b8a..4b4d999af 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1965,6 +1965,19 @@ config SENSORS_SMM665
> This driver can also be built as a module. If so, the module will
> be called smm665.
>
> +config SENSORS_SURFACE_FAN
> + tristate "Surface Fan Driver"
> + depends on SURFACE_AGGREGATOR
> + help
> + Driver that provides monitoring of the fan on Surface Pro devices that
> + have a fan, like the Surface Pro 9.
> +
> + This makes the fan's current speed accessible through the hwmon
> + system. It does not provide control over the fan, the firmware is
> + responsible for that, this driver merely provides monitoring.
> +
> + Select M or Y here, if you want to be able to read the fan's speed.
> +
> config SENSORS_ADC128D818
> tristate "Texas Instruments ADC128D818"
> depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 3f4b0fda0..5ae214c06 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -198,6 +198,7 @@ obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o
> obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
> obj-$(CONFIG_SENSORS_SPARX5) += sparx5-temp.o
> obj-$(CONFIG_SENSORS_STTS751) += stts751.o
> +obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o
> obj-$(CONFIG_SENSORS_SY7636A) += sy7636a-hwmon.o
> obj-$(CONFIG_SENSORS_AMC6821) += amc6821.o
> obj-$(CONFIG_SENSORS_TC74) += tc74.o
> diff --git a/drivers/hwmon/surface_fan.c b/drivers/hwmon/surface_fan.c
> new file mode 100644
> index 000000000..7c2e3ae3e
> --- /dev/null
> +++ b/drivers/hwmon/surface_fan.c
> @@ -0,0 +1,93 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Surface Fan driver for Surface System Aggregator Module. It provides access
> + * to the fan's rpm through the hwmon system.
> + *
> + * Copyright (C) 2023 Ivor Wanders <[email protected]>
> + */
> +
> +#include <linux/hwmon.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/surface_aggregator/device.h>
> +#include <linux/types.h>
> +
> +// SSAM
> +SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_fan_rpm_get, __le16, {
> + .target_category = SSAM_SSH_TC_FAN,
> + .command_id = 0x01,
> +});
> +
> +// hwmon
> +umode_t surface_fan_hwmon_is_visible(const void *drvdata,
> + enum hwmon_sensor_types type, u32 attr,
> + int channel)
> +{
> + return 0444;
> +}
> +
> +static int surface_fan_hwmon_read(struct device *dev,
> + enum hwmon_sensor_types type, u32 attr,
> + int channel, long *val)
> +{
> + struct ssam_device *sdev = dev_get_drvdata(dev);
> + int ret;
> + __le16 value;
> +
> + ret = __ssam_fan_rpm_get(sdev, &value);
> + if (ret)
> + return ret;
> +
> + *val = le16_to_cpu(value);
> +
> + return ret;
Hello,
maybe you can just return 0 here.
> +}
> +
> +static const struct hwmon_channel_info *const surface_fan_info[] = {
> + HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
> + NULL
> +};
> +
> +static const struct hwmon_ops surface_fan_hwmon_ops = {
> + .is_visible = surface_fan_hwmon_is_visible,
> + .read = surface_fan_hwmon_read,
> +};
> +
> +static const struct hwmon_chip_info surface_fan_chip_info = {
> + .ops = &surface_fan_hwmon_ops,
> + .info = surface_fan_info,
> +};
> +
> +static int surface_fan_probe(struct ssam_device *sdev)
> +{
> + struct device *hdev;
> +
> + hdev = devm_hwmon_device_register_with_info(&sdev->dev,
> + "surface_fan", sdev,
> + &surface_fan_chip_info,
> + NULL);
> + if (IS_ERR(hdev))
> + return PTR_ERR(hdev);
> +
> + return 0;
Maybe use PTR_ERR_OR_ZERO() here?
Other than those two small things:
Reviewed-by: Armin Wolf <[email protected]>
> +}
> +
> +static const struct ssam_device_id ssam_fan_match[] = {
> + { SSAM_SDEV(FAN, SAM, 0x01, 0x01) },
> + {},
> +};
> +MODULE_DEVICE_TABLE(ssam, ssam_fan_match);
> +
> +static struct ssam_device_driver surface_fan = {
> + .probe = surface_fan_probe,
> + .match_table = ssam_fan_match,
> + .driver = {
> + .name = "surface_fan",
> + .probe_type = PROBE_PREFER_ASYNCHRONOUS,
> + },
> +};
> +module_ssam_device_driver(surface_fan);
> +
> +MODULE_AUTHOR("Ivor Wanders <[email protected]>");
> +MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module");
> +MODULE_LICENSE("GPL");
Hello Armin, thank you for your second review.
> maybe you can just return 0 here.
Good idea, that's indeed the only option for ret, so that makes it clearer.
> Maybe use PTR_ERR_OR_ZERO() here?
Definitely, thanks for suggesting this; cleans it up nicely.
~Ivor