Re: [PATCH 1/3] hwmon: Add thermal sensor driver for Surface Aggregator Module

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 3/30/24 12:24 PM, Maximilian Luz wrote:
> Some of the newer Microsoft Surface devices (such as the Surface Book
> 3 and Pro 9) have thermal sensors connected via the Surface Aggregator
> Module (the embedded controller on those devices). Add a basic driver
> to read out the temperature values of those sensors.
> 
> Link: https://github.com/linux-surface/surface-aggregator-module/issues/59
> Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans



> ---
>  MAINTAINERS                  |   6 ++
>  drivers/hwmon/Kconfig        |  10 +++
>  drivers/hwmon/Makefile       |   1 +
>  drivers/hwmon/surface_temp.c | 165 +++++++++++++++++++++++++++++++++++
>  4 files changed, 182 insertions(+)
>  create mode 100644 drivers/hwmon/surface_temp.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d36c19c1bf811..bc5bc418ed479 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14738,6 +14738,12 @@ S:	Maintained
>  F:	Documentation/hwmon/surface_fan.rst
>  F:	drivers/hwmon/surface_fan.c
>  
> +MICROSOFT SURFACE SENSOR THERMAL DRIVER
> +M:	Maximilian Luz <luzmaximilian@gmail.com>
> +L:	linux-hwmon@vger.kernel.org
> +S:	Maintained
> +F:	drivers/hwmon/surface_temp.c
> +
>  MICROSOFT SURFACE GPE LID SUPPORT DRIVER
>  M:	Maximilian Luz <luzmaximilian@gmail.com>
>  L:	platform-driver-x86@vger.kernel.org
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 83945397b6eb1..338ef73c96a3a 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -2070,6 +2070,16 @@ config SENSORS_SURFACE_FAN
>  
>  	  Select M or Y here, if you want to be able to read the fan's speed.
>  
> +config SENSORS_SURFACE_TEMP
> +	tristate "Microsoft Surface Thermal Sensor Driver"
> +	depends on SURFACE_AGGREGATOR
> +	help
> +	  Driver for monitoring thermal sensors connected via the Surface
> +	  Aggregator Module (embedded controller) on Microsoft Surface devices.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called surface_temp.
> +
>  config SENSORS_ADC128D818
>  	tristate "Texas Instruments ADC128D818"
>  	depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 5c31808f6378d..de8bc99719e63 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -208,6 +208,7 @@ 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-$(CONFIG_SENSORS_SURFACE_TEMP)+= surface_temp.o
>  obj-$(CONFIG_SENSORS_SY7636A)	+= sy7636a-hwmon.o
>  obj-$(CONFIG_SENSORS_AMC6821)	+= amc6821.o
>  obj-$(CONFIG_SENSORS_TC74)	+= tc74.o
> diff --git a/drivers/hwmon/surface_temp.c b/drivers/hwmon/surface_temp.c
> new file mode 100644
> index 0000000000000..48c3e826713f6
> --- /dev/null
> +++ b/drivers/hwmon/surface_temp.c
> @@ -0,0 +1,165 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Thermal sensor subsystem driver for Surface System Aggregator Module (SSAM).
> + *
> + * Copyright (C) 2022-2023 Maximilian Luz <luzmaximilian@gmail.com>
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/hwmon.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/types.h>
> +
> +#include <linux/surface_aggregator/controller.h>
> +#include <linux/surface_aggregator/device.h>
> +
> +
> +/* -- SAM interface. -------------------------------------------------------- */
> +
> +SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_tmp_get_available_sensors, __le16, {
> +	.target_category = SSAM_SSH_TC_TMP,
> +	.command_id      = 0x04,
> +});
> +
> +SSAM_DEFINE_SYNC_REQUEST_MD_R(__ssam_tmp_get_temperature, __le16, {
> +	.target_category = SSAM_SSH_TC_TMP,
> +	.command_id      = 0x01,
> +});
> +
> +static int ssam_tmp_get_available_sensors(struct ssam_device *sdev, s16 *sensors)
> +{
> +	__le16 sensors_le;
> +	int status;
> +
> +	status = __ssam_tmp_get_available_sensors(sdev, &sensors_le);
> +	if (status)
> +		return status;
> +
> +	*sensors = le16_to_cpu(sensors_le);
> +	return 0;
> +}
> +
> +static int ssam_tmp_get_temperature(struct ssam_device *sdev, u8 iid, long *temperature)
> +{
> +	__le16 temp_le;
> +	int status;
> +
> +	status = __ssam_tmp_get_temperature(sdev->ctrl, sdev->uid.target, iid, &temp_le);
> +	if (status)
> +		return status;
> +
> +	/* Convert 1/10 °K to 1/1000 °C */
> +	*temperature = (le16_to_cpu(temp_le) - 2731) * 100L;
> +	return 0;
> +}
> +
> +
> +/* -- Driver.---------------------------------------------------------------- */
> +
> +struct ssam_temp {
> +	struct ssam_device *sdev;
> +	s16 sensors;
> +};
> +
> +static umode_t ssam_temp_hwmon_is_visible(const void *data,
> +					  enum hwmon_sensor_types type,
> +					  u32 attr, int channel)
> +{
> +	const struct ssam_temp *ssam_temp = data;
> +
> +	if (!(ssam_temp->sensors & BIT(channel)))
> +		return 0;
> +
> +	return 0444;
> +}
> +
> +static int ssam_temp_hwmon_read(struct device *dev,
> +				enum hwmon_sensor_types type,
> +				u32 attr, int channel, long *value)
> +{
> +	const struct ssam_temp *ssam_temp = dev_get_drvdata(dev);
> +
> +	return ssam_tmp_get_temperature(ssam_temp->sdev, channel + 1, value);
> +}
> +
> +static const struct hwmon_channel_info * const ssam_temp_hwmon_info[] = {
> +	HWMON_CHANNEL_INFO(chip,
> +			   HWMON_C_REGISTER_TZ),
> +	/* We have at most 16 thermal sensor channels. */
> +	HWMON_CHANNEL_INFO(temp,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT,
> +			   HWMON_T_INPUT),
> +	NULL
> +};
> +
> +static const struct hwmon_ops ssam_temp_hwmon_ops = {
> +	.is_visible = ssam_temp_hwmon_is_visible,
> +	.read = ssam_temp_hwmon_read,
> +};
> +
> +static const struct hwmon_chip_info ssam_temp_hwmon_chip_info = {
> +	.ops = &ssam_temp_hwmon_ops,
> +	.info = ssam_temp_hwmon_info,
> +};
> +
> +static int ssam_temp_probe(struct ssam_device *sdev)
> +{
> +	struct ssam_temp *ssam_temp;
> +	struct device *hwmon_dev;
> +	s16 sensors;
> +	int status;
> +
> +	status = ssam_tmp_get_available_sensors(sdev, &sensors);
> +	if (status)
> +		return status;
> +
> +	ssam_temp = devm_kzalloc(&sdev->dev, sizeof(*ssam_temp), GFP_KERNEL);
> +	if (!ssam_temp)
> +		return -ENOMEM;
> +
> +	ssam_temp->sdev = sdev;
> +	ssam_temp->sensors = sensors;
> +
> +	hwmon_dev = devm_hwmon_device_register_with_info(&sdev->dev,
> +			"surface_thermal", ssam_temp, &ssam_temp_hwmon_chip_info,
> +			NULL);
> +	if (IS_ERR(hwmon_dev))
> +		return PTR_ERR(hwmon_dev);
> +
> +	return 0;
> +}
> +
> +static const struct ssam_device_id ssam_temp_match[] = {
> +	{ SSAM_SDEV(TMP, SAM, 0x00, 0x02) },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(ssam, ssam_temp_match);
> +
> +static struct ssam_device_driver ssam_temp = {
> +	.probe = ssam_temp_probe,
> +	.match_table = ssam_temp_match,
> +	.driver = {
> +		.name = "surface_temp",
> +		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
> +	},
> +};
> +module_ssam_device_driver(ssam_temp);
> +
> +MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
> +MODULE_DESCRIPTION("Thermal sensor subsystem driver for Surface System Aggregator Module");
> +MODULE_LICENSE("GPL");