[PATCH v7 0/1] platform/x86: Introduce dasharo-acpi platform driver

[PATCH v7 0/1] platform/x86: Introduce dasharo-acpi platform driver

[Michał Kopeć]

Introduce a driver for devices running Dasharo firmware. The driver
supports thermal monitoring using a new ACPI interface in Dasharo. The
initial version supports monitoring fan speeds, fan PWM duty cycles and
system temperatures as well as determining which specific interfaces are
implemented by firmware.

It has been tested on a NovaCustom laptop running pre-release Dasharo
firmware, which implements fan and thermal monitoring for the CPU and
the discrete GPU, if present.

Changes in v2:
- Remove redundant copyright information
- Turn dasharo_fill_* functions into single dasharo_fill_feature_caps
  function
- Code style fixes
- Turn large if / else blocks into switch / case
- Fix possible positive return values in hwmon read handler
- Change while loops to for loops
- Add local variable for data->sensors[data->sensors_count] in
  dasharo_fill_feature_caps
- Replace snprintf with scnprintf per Ilpo's review
- Keep the "ok" path silent

Changes in V3:
- Simplify dasharo_read_value_by_cap_idx arguments and rename to
  dasharo_read_channel

Changes in V4:
- Remove unnecessary linebreaks
- Simplify naming of variables
- Constify zone lookup table
- Remove unneeded includes
- Switch to platform_device API
- Remove unneeded driver remove handler
- Add myself to MAINTAINERS

Changes in V5:
- Fix up the MAINTAINERS entry
- Use PTR_ERR_OR_ZERO for the hwmon pointer in the register func
- Simplify if blocks in dasharo_hwmon_read
- Use ACPI_FAILURE instead of !ACPI_SUCCESS

Changes in V6:
- Validate input parameters in dasharo_read_channel
- Add default return code in dasharo_hwmon_read
- Return error if invalid channel is requested in hwmon_read_string
- Add missing include for ARRAY_SIZE
- Align line continuations in dasharo_probe

Changes in V7:
- Use cap count for bound checking in dasharo_read_channel

Michał Kopeć (1):
  platform/x86: Introduce dasharo-acpi platform driver

 MAINTAINERS                         |   6 +
 drivers/platform/x86/Kconfig        |  10 +
 drivers/platform/x86/Makefile       |   3 +
 drivers/platform/x86/dasharo-acpi.c | 357 ++++++++++++++++++++++++++++
 4 files changed, 376 insertions(+)
 create mode 100644 drivers/platform/x86/dasharo-acpi.c

-- 
2.49.0

[PATCH v7 1/1] platform/x86: Introduce dasharo-acpi platform driver

[Michał Kopeć]

Introduce a driver for devices running Dasharo firmware. The driver
supports thermal monitoring using a new ACPI interface in Dasharo. The
initial version supports monitoring fan speeds, fan PWM duty cycles and
system temperatures as well as determining which specific interfaces are
implemented by firmware.

It has been tested on a NovaCustom laptop running pre-release Dasharo
firmware, which implements fan and thermal monitoring for the CPU and
the discrete GPU, if present.

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Michał Kopeć <michal.kopec@3mdeb.com>

Address Ilpo's review

Signed-off-by: Michał Kopeć <michal.kopec@3mdeb.com>
---
 MAINTAINERS                         |   6 +
 drivers/platform/x86/Kconfig        |  10 +
 drivers/platform/x86/Makefile       |   3 +
 drivers/platform/x86/dasharo-acpi.c | 357 ++++++++++++++++++++++++++++
 4 files changed, 376 insertions(+)
 create mode 100644 drivers/platform/x86/dasharo-acpi.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 00e94bec401e..6d2e0909ac63 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6404,6 +6404,12 @@ F:	net/ax25/ax25_out.c
 F:	net/ax25/ax25_timer.c
 F:	net/ax25/sysctl_net_ax25.c
 
+DASHARO ACPI PLATFORM DRIVER
+M:	Michał Kopeć <michal.kopec@3mdeb.com>
+S:	Maintained
+W:	https://docs.dasharo.com/
+F:	drivers/platform/x86/dasharo_acpi.c
+
 DATA ACCESS MONITOR
 M:	SeongJae Park <sj@kernel.org>
 L:	damon@lists.linux.dev
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 0258dd879d64..8168c5274a08 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1060,6 +1060,16 @@ config LENOVO_WMI_CAMERA
 	  To compile this driver as a module, choose M here: the module
 	  will be called lenovo-wmi-camera.
 
+config DASHARO_ACPI
+	tristate "Dasharo ACPI Platform Driver"
+	depends on ACPI
+	depends on HWMON
+	help
+	  This driver provides HWMON support for devices running Dasharo
+	  firmware.
+
+	  If you have a device with Dasharo firmware, choose Y or M here.
+
 source "drivers/platform/x86/x86-android-tablets/Kconfig"
 
 config FW_ATTR_CLASS
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index e1b142947067..3ca53ae01d93 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -110,6 +110,9 @@ obj-$(CONFIG_ACPI_TOSHIBA)	+= toshiba_acpi.o
 # Inspur
 obj-$(CONFIG_INSPUR_PLATFORM_PROFILE)	+= inspur_platform_profile.o
 
+# Dasharo
+obj-$(CONFIG_DASHARO_ACPI)	+= dasharo-acpi.o
+
 # Laptop drivers
 obj-$(CONFIG_ACPI_CMPC)		+= classmate-laptop.o
 obj-$(CONFIG_COMPAL_LAPTOP)	+= compal-laptop.o
diff --git a/drivers/platform/x86/dasharo-acpi.c b/drivers/platform/x86/dasharo-acpi.c
new file mode 100644
index 000000000000..f3f01d4604b5
--- /dev/null
+++ b/drivers/platform/x86/dasharo-acpi.c
@@ -0,0 +1,357 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Dasharo ACPI Driver
+ */
+
+#include <linux/acpi.h>
+#include <linux/array_size.h>
+#include <linux/hwmon.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/units.h>
+
+enum dasharo_feature {
+	DASHARO_FEATURE_TEMPERATURE = 0,
+	DASHARO_FEATURE_FAN_PWM,
+	DASHARO_FEATURE_FAN_TACH,
+	DASHARO_FEATURE_MAX
+};
+
+enum dasharo_temperature {
+	DASHARO_TEMPERATURE_CPU_PACKAGE = 0,
+	DASHARO_TEMPERATURE_CPU_CORE,
+	DASHARO_TEMPERATURE_GPU,
+	DASHARO_TEMPERATURE_BOARD,
+	DASHARO_TEMPERATURE_CHASSIS,
+	DASHARO_TEMPERATURE_MAX
+};
+
+enum dasharo_fan {
+	DASHARO_FAN_CPU = 0,
+	DASHARO_FAN_GPU,
+	DASHARO_FAN_CHASSIS,
+	DASHARO_FAN_MAX
+};
+
+#define MAX_GROUPS_PER_FEAT 8
+
+static const char * const dasharo_group_names[DASHARO_FEATURE_MAX][MAX_GROUPS_PER_FEAT] = {
+	[DASHARO_FEATURE_TEMPERATURE] = {
+		[DASHARO_TEMPERATURE_CPU_PACKAGE] = "CPU Package",
+		[DASHARO_TEMPERATURE_CPU_CORE] = "CPU Core",
+		[DASHARO_TEMPERATURE_GPU] = "GPU",
+		[DASHARO_TEMPERATURE_BOARD] = "Board",
+		[DASHARO_TEMPERATURE_CHASSIS] = "Chassis",
+	},
+	[DASHARO_FEATURE_FAN_PWM] = {
+		[DASHARO_FAN_CPU] = "CPU",
+		[DASHARO_FAN_GPU] = "GPU",
+		[DASHARO_FAN_CHASSIS] = "Chassis",
+	},
+	[DASHARO_FEATURE_FAN_TACH] = {
+		[DASHARO_FAN_CPU] = "CPU",
+		[DASHARO_FAN_GPU] = "GPU",
+		[DASHARO_FAN_CHASSIS] = "Chassis",
+	},
+};
+
+struct dasharo_capability {
+	unsigned int group;
+	unsigned int index;
+	char name[16];
+};
+
+#define MAX_CAPS_PER_FEAT 24
+
+struct dasharo_data {
+	struct platform_device *pdev;
+	int caps_found[DASHARO_FEATURE_MAX];
+	struct dasharo_capability capabilities[DASHARO_FEATURE_MAX][MAX_CAPS_PER_FEAT];
+};
+
+static int dasharo_get_feature_cap_count(struct dasharo_data *data, enum dasharo_feature feat, int cap)
+{
+	struct acpi_object_list obj_list;
+	union acpi_object obj[2];
+	acpi_handle handle;
+	acpi_status status;
+	u64 count;
+
+	obj[0].type = ACPI_TYPE_INTEGER;
+	obj[0].integer.value = feat;
+	obj[1].type = ACPI_TYPE_INTEGER;
+	obj[1].integer.value = cap;
+	obj_list.count = 2;
+	obj_list.pointer = &obj[0];
+
+	handle = ACPI_HANDLE(&data->pdev->dev);
+	status = acpi_evaluate_integer(handle, "GFCP", &obj_list, &count);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	return count;
+}
+
+static int dasharo_read_channel(struct dasharo_data *data, char *method, enum dasharo_feature feat, int channel, long *value)
+{
+	struct acpi_object_list obj_list;
+	union acpi_object obj[2];
+	acpi_handle handle;
+	acpi_status status;
+	u64 val;
+
+	if (feat > ARRAY_SIZE(data->capabilities))
+		return -EINVAL;
+
+	if (channel > data->caps_found[feat])
+		return -EINVAL;
+
+	obj[0].type = ACPI_TYPE_INTEGER;
+	obj[0].integer.value = data->capabilities[feat][channel].group;
+	obj[1].type = ACPI_TYPE_INTEGER;
+	obj[1].integer.value = data->capabilities[feat][channel].index;
+	obj_list.count = 2;
+	obj_list.pointer = &obj[0];
+
+	handle = ACPI_HANDLE(&data->pdev->dev);
+	status = acpi_evaluate_integer(handle, method, &obj_list, &val);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	*value = val;
+	return 0;
+}
+
+static int dasharo_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+			      u32 attr, int channel, long *val)
+{
+	struct dasharo_data *data = dev_get_drvdata(dev);
+	long value;
+	int ret;
+
+	switch (type) {
+	case hwmon_temp:
+		ret = dasharo_read_channel(data, "GTMP", DASHARO_FEATURE_TEMPERATURE, channel, &value);
+		if (!ret)
+			*val = value * MILLIDEGREE_PER_DEGREE;
+		break;
+	case hwmon_fan:
+		ret = dasharo_read_channel(data, "GFTH", DASHARO_FEATURE_FAN_TACH, channel, &value);
+		if (!ret)
+			*val = value;
+		break;
+	case hwmon_pwm:
+		ret = dasharo_read_channel(data, "GFDC", DASHARO_FEATURE_FAN_PWM, channel, &value);
+		if (!ret)
+			*val = value;
+		break;
+	default:
+		return -ENODEV;
+		break;
+	}
+
+	return ret;
+}
+
+static int dasharo_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
+				     u32 attr, int channel, const char **str)
+{
+	struct dasharo_data *data = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_temp:
+		if (channel >= data->caps_found[DASHARO_FEATURE_TEMPERATURE])
+			return -EINVAL;
+
+		*str = data->capabilities[DASHARO_FEATURE_TEMPERATURE][channel].name;
+		break;
+	case hwmon_fan:
+		if (channel >= data->caps_found[DASHARO_FEATURE_FAN_TACH])
+			return -EINVAL;
+
+		*str = data->capabilities[DASHARO_FEATURE_FAN_TACH][channel].name;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static umode_t dasharo_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_types type,
+					u32 attr, int channel)
+{
+	const struct dasharo_data *data = drvdata;
+
+	switch (type) {
+	case hwmon_temp:
+		if (channel < data->caps_found[DASHARO_FEATURE_TEMPERATURE])
+			return 0444;
+		break;
+	case hwmon_pwm:
+		if (channel < data->caps_found[DASHARO_FEATURE_FAN_PWM])
+			return 0444;
+		break;
+	case hwmon_fan:
+		if (channel < data->caps_found[DASHARO_FEATURE_FAN_TACH])
+			return 0444;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static const struct hwmon_ops dasharo_hwmon_ops = {
+	.is_visible = dasharo_hwmon_is_visible,
+	.read_string = dasharo_hwmon_read_string,
+	.read = dasharo_hwmon_read,
+};
+
+// Max 24 capabilities per feature
+static const struct hwmon_channel_info * const dasharo_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(fan,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL,
+		HWMON_F_INPUT | HWMON_F_LABEL),
+	HWMON_CHANNEL_INFO(temp,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL,
+		HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(pwm,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT,
+		HWMON_PWM_INPUT),
+	NULL
+};
+
+static const struct hwmon_chip_info dasharo_hwmon_chip_info = {
+	.ops = &dasharo_hwmon_ops,
+	.info = dasharo_hwmon_info,
+};
+
+static void dasharo_fill_feature_caps(struct dasharo_data *data, enum dasharo_feature feat)
+{
+	struct dasharo_capability *cap;
+	int cap_count = 0;
+	int count;
+
+	for (int group = 0; group < MAX_GROUPS_PER_FEAT; ++group) {
+		count = dasharo_get_feature_cap_count(data, feat, group);
+
+		if (count <= 0)
+			continue;
+
+		for (unsigned int i = 0; i < count && cap_count < ARRAY_SIZE(data->capabilities[feat]); ++i) {
+			cap = &data->capabilities[feat][cap_count];
+			cap->group = group;
+			cap->index = i;
+			scnprintf(cap->name, sizeof(cap->name), "%s %d", dasharo_group_names[feat][group], i);
+			cap_count++;
+		}
+	}
+	data->caps_found[feat] = cap_count;
+}
+
+static int dasharo_probe(struct platform_device *pdev)
+{
+	struct dasharo_data *data;
+	struct device *hwmon;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	data->pdev = pdev;
+
+	for (unsigned int i = 0; i < DASHARO_FEATURE_MAX; ++i)
+		dasharo_fill_feature_caps(data, i);
+
+	hwmon = devm_hwmon_device_register_with_info(&pdev->dev, "dasharo_acpi", data,
+						     &dasharo_hwmon_chip_info, NULL);
+
+	return PTR_ERR_OR_ZERO(hwmon);
+}
+
+static const struct acpi_device_id dasharo_device_ids[] = {
+	{"DSHR0001", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, dasharo_device_ids);
+
+static struct platform_driver dasharo_driver = {
+	.driver = {
+		.name = "dasharo-acpi",
+		.acpi_match_table = dasharo_device_ids,
+	},
+	.probe = dasharo_probe,
+};
+module_platform_driver(dasharo_driver);
+
+MODULE_DESCRIPTION("Dasharo ACPI Driver");
+MODULE_AUTHOR("Michał Kopeć <michal.kopec@3mdeb.com>");
+MODULE_LICENSE("GPL");
-- 
2.49.0

Re: [PATCH v7 1/1] platform/x86: Introduce dasharo-acpi platform driver

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 14375 bytes --]

On Mon, 7 Apr 2025, Michał Kopeć wrote:

> Introduce a driver for devices running Dasharo firmware. The driver
> supports thermal monitoring using a new ACPI interface in Dasharo. The
> initial version supports monitoring fan speeds, fan PWM duty cycles and
> system temperatures as well as determining which specific interfaces are
> implemented by firmware.
> 
> It has been tested on a NovaCustom laptop running pre-release Dasharo
> firmware, which implements fan and thermal monitoring for the CPU and
> the discrete GPU, if present.
> 
> Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
> Signed-off-by: Michał Kopeć <michal.kopec@3mdeb.com>
> 
> Address Ilpo's review
> 
> Signed-off-by: Michał Kopeć <michal.kopec@3mdeb.com>
> ---
>  MAINTAINERS                         |   6 +
>  drivers/platform/x86/Kconfig        |  10 +
>  drivers/platform/x86/Makefile       |   3 +
>  drivers/platform/x86/dasharo-acpi.c | 357 ++++++++++++++++++++++++++++
>  4 files changed, 376 insertions(+)
>  create mode 100644 drivers/platform/x86/dasharo-acpi.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 00e94bec401e..6d2e0909ac63 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6404,6 +6404,12 @@ F:	net/ax25/ax25_out.c
>  F:	net/ax25/ax25_timer.c
>  F:	net/ax25/sysctl_net_ax25.c
>  
> +DASHARO ACPI PLATFORM DRIVER
> +M:	Michał Kopeć <michal.kopec@3mdeb.com>
> +S:	Maintained
> +W:	https://docs.dasharo.com/
> +F:	drivers/platform/x86/dasharo_acpi.c
> +
>  DATA ACCESS MONITOR
>  M:	SeongJae Park <sj@kernel.org>
>  L:	damon@lists.linux.dev
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 0258dd879d64..8168c5274a08 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -1060,6 +1060,16 @@ config LENOVO_WMI_CAMERA
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called lenovo-wmi-camera.
>  
> +config DASHARO_ACPI
> +	tristate "Dasharo ACPI Platform Driver"
> +	depends on ACPI
> +	depends on HWMON
> +	help
> +	  This driver provides HWMON support for devices running Dasharo
> +	  firmware.
> +
> +	  If you have a device with Dasharo firmware, choose Y or M here.
> +
>  source "drivers/platform/x86/x86-android-tablets/Kconfig"
>  
>  config FW_ATTR_CLASS
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index e1b142947067..3ca53ae01d93 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -110,6 +110,9 @@ obj-$(CONFIG_ACPI_TOSHIBA)	+= toshiba_acpi.o
>  # Inspur
>  obj-$(CONFIG_INSPUR_PLATFORM_PROFILE)	+= inspur_platform_profile.o
>  
> +# Dasharo
> +obj-$(CONFIG_DASHARO_ACPI)	+= dasharo-acpi.o
> +
>  # Laptop drivers
>  obj-$(CONFIG_ACPI_CMPC)		+= classmate-laptop.o
>  obj-$(CONFIG_COMPAL_LAPTOP)	+= compal-laptop.o
> diff --git a/drivers/platform/x86/dasharo-acpi.c b/drivers/platform/x86/dasharo-acpi.c
> new file mode 100644
> index 000000000000..f3f01d4604b5
> --- /dev/null
> +++ b/drivers/platform/x86/dasharo-acpi.c
> @@ -0,0 +1,357 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Dasharo ACPI Driver
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/array_size.h>
> +#include <linux/hwmon.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/types.h>
> +#include <linux/units.h>
> +
> +enum dasharo_feature {
> +	DASHARO_FEATURE_TEMPERATURE = 0,
> +	DASHARO_FEATURE_FAN_PWM,
> +	DASHARO_FEATURE_FAN_TACH,
> +	DASHARO_FEATURE_MAX
> +};
> +
> +enum dasharo_temperature {
> +	DASHARO_TEMPERATURE_CPU_PACKAGE = 0,
> +	DASHARO_TEMPERATURE_CPU_CORE,
> +	DASHARO_TEMPERATURE_GPU,
> +	DASHARO_TEMPERATURE_BOARD,
> +	DASHARO_TEMPERATURE_CHASSIS,
> +	DASHARO_TEMPERATURE_MAX
> +};
> +
> +enum dasharo_fan {
> +	DASHARO_FAN_CPU = 0,
> +	DASHARO_FAN_GPU,
> +	DASHARO_FAN_CHASSIS,
> +	DASHARO_FAN_MAX
> +};
> +
> +#define MAX_GROUPS_PER_FEAT 8
> +
> +static const char * const dasharo_group_names[DASHARO_FEATURE_MAX][MAX_GROUPS_PER_FEAT] = {
> +	[DASHARO_FEATURE_TEMPERATURE] = {
> +		[DASHARO_TEMPERATURE_CPU_PACKAGE] = "CPU Package",
> +		[DASHARO_TEMPERATURE_CPU_CORE] = "CPU Core",
> +		[DASHARO_TEMPERATURE_GPU] = "GPU",
> +		[DASHARO_TEMPERATURE_BOARD] = "Board",
> +		[DASHARO_TEMPERATURE_CHASSIS] = "Chassis",
> +	},
> +	[DASHARO_FEATURE_FAN_PWM] = {
> +		[DASHARO_FAN_CPU] = "CPU",
> +		[DASHARO_FAN_GPU] = "GPU",
> +		[DASHARO_FAN_CHASSIS] = "Chassis",
> +	},
> +	[DASHARO_FEATURE_FAN_TACH] = {
> +		[DASHARO_FAN_CPU] = "CPU",
> +		[DASHARO_FAN_GPU] = "GPU",
> +		[DASHARO_FAN_CHASSIS] = "Chassis",
> +	},
> +};
> +
> +struct dasharo_capability {
> +	unsigned int group;
> +	unsigned int index;
> +	char name[16];
> +};
> +
> +#define MAX_CAPS_PER_FEAT 24
> +
> +struct dasharo_data {
> +	struct platform_device *pdev;
> +	int caps_found[DASHARO_FEATURE_MAX];
> +	struct dasharo_capability capabilities[DASHARO_FEATURE_MAX][MAX_CAPS_PER_FEAT];
> +};
> +
> +static int dasharo_get_feature_cap_count(struct dasharo_data *data, enum dasharo_feature feat, int cap)
> +{
> +	struct acpi_object_list obj_list;
> +	union acpi_object obj[2];
> +	acpi_handle handle;
> +	acpi_status status;
> +	u64 count;
> +
> +	obj[0].type = ACPI_TYPE_INTEGER;
> +	obj[0].integer.value = feat;
> +	obj[1].type = ACPI_TYPE_INTEGER;
> +	obj[1].integer.value = cap;
> +	obj_list.count = 2;
> +	obj_list.pointer = &obj[0];
> +
> +	handle = ACPI_HANDLE(&data->pdev->dev);
> +	status = acpi_evaluate_integer(handle, "GFCP", &obj_list, &count);
> +	if (ACPI_FAILURE(status))
> +		return -ENODEV;
> +
> +	return count;
> +}
> +
> +static int dasharo_read_channel(struct dasharo_data *data, char *method, enum dasharo_feature feat, int channel, long *value)
> +{
> +	struct acpi_object_list obj_list;
> +	union acpi_object obj[2];
> +	acpi_handle handle;
> +	acpi_status status;
> +	u64 val;
> +
> +	if (feat > ARRAY_SIZE(data->capabilities))
> +		return -EINVAL;
> +
> +	if (channel > data->caps_found[feat])
> +		return -EINVAL;
> +
> +	obj[0].type = ACPI_TYPE_INTEGER;
> +	obj[0].integer.value = data->capabilities[feat][channel].group;
> +	obj[1].type = ACPI_TYPE_INTEGER;
> +	obj[1].integer.value = data->capabilities[feat][channel].index;
> +	obj_list.count = 2;
> +	obj_list.pointer = &obj[0];
> +
> +	handle = ACPI_HANDLE(&data->pdev->dev);
> +	status = acpi_evaluate_integer(handle, method, &obj_list, &val);
> +	if (ACPI_FAILURE(status))
> +		return -ENODEV;
> +
> +	*value = val;
> +	return 0;
> +}
> +
> +static int dasharo_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
> +			      u32 attr, int channel, long *val)
> +{
> +	struct dasharo_data *data = dev_get_drvdata(dev);
> +	long value;
> +	int ret;
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		ret = dasharo_read_channel(data, "GTMP", DASHARO_FEATURE_TEMPERATURE, channel, &value);
> +		if (!ret)
> +			*val = value * MILLIDEGREE_PER_DEGREE;
> +		break;
> +	case hwmon_fan:
> +		ret = dasharo_read_channel(data, "GFTH", DASHARO_FEATURE_FAN_TACH, channel, &value);
> +		if (!ret)
> +			*val = value;
> +		break;
> +	case hwmon_pwm:
> +		ret = dasharo_read_channel(data, "GFDC", DASHARO_FEATURE_FAN_PWM, channel, &value);
> +		if (!ret)
> +			*val = value;
> +		break;
> +	default:
> +		return -ENODEV;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static int dasharo_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
> +				     u32 attr, int channel, const char **str)
> +{
> +	struct dasharo_data *data = dev_get_drvdata(dev);
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		if (channel >= data->caps_found[DASHARO_FEATURE_TEMPERATURE])
> +			return -EINVAL;
> +
> +		*str = data->capabilities[DASHARO_FEATURE_TEMPERATURE][channel].name;
> +		break;
> +	case hwmon_fan:
> +		if (channel >= data->caps_found[DASHARO_FEATURE_FAN_TACH])
> +			return -EINVAL;
> +
> +		*str = data->capabilities[DASHARO_FEATURE_FAN_TACH][channel].name;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return 0;
> +}
> +
> +static umode_t dasharo_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_types type,
> +					u32 attr, int channel)
> +{
> +	const struct dasharo_data *data = drvdata;
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		if (channel < data->caps_found[DASHARO_FEATURE_TEMPERATURE])
> +			return 0444;
> +		break;
> +	case hwmon_pwm:
> +		if (channel < data->caps_found[DASHARO_FEATURE_FAN_PWM])
> +			return 0444;
> +		break;
> +	case hwmon_fan:
> +		if (channel < data->caps_found[DASHARO_FEATURE_FAN_TACH])
> +			return 0444;
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct hwmon_ops dasharo_hwmon_ops = {
> +	.is_visible = dasharo_hwmon_is_visible,
> +	.read_string = dasharo_hwmon_read_string,
> +	.read = dasharo_hwmon_read,
> +};
> +
> +// Max 24 capabilities per feature
> +static const struct hwmon_channel_info * const dasharo_hwmon_info[] = {
> +	HWMON_CHANNEL_INFO(fan,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL,
> +		HWMON_F_INPUT | HWMON_F_LABEL),
> +	HWMON_CHANNEL_INFO(temp,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL,
> +		HWMON_T_INPUT | HWMON_T_LABEL),
> +	HWMON_CHANNEL_INFO(pwm,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT,
> +		HWMON_PWM_INPUT),
> +	NULL
> +};
> +
> +static const struct hwmon_chip_info dasharo_hwmon_chip_info = {
> +	.ops = &dasharo_hwmon_ops,
> +	.info = dasharo_hwmon_info,
> +};
> +
> +static void dasharo_fill_feature_caps(struct dasharo_data *data, enum dasharo_feature feat)
> +{
> +	struct dasharo_capability *cap;
> +	int cap_count = 0;
> +	int count;
> +
> +	for (int group = 0; group < MAX_GROUPS_PER_FEAT; ++group) {
> +		count = dasharo_get_feature_cap_count(data, feat, group);
> +
> +		if (count <= 0)

This relates to the previous line, it's sort of error handling so please 
remove the empty line between them.

> +			continue;
> +
> +		for (unsigned int i = 0; i < count && cap_count < ARRAY_SIZE(data->capabilities[feat]); ++i) {

This exceeds 100 chars which is the current hard limit for code line 
lengths.

I suggest you make that cap_count check a separate if () check, I'm not 
sure though if it should just goto to the final assignment of the function 
as there's nothing more to do here in these loops if the array fills up
(or break the inner loop, that reads a few counts unnecessarily in the 
outer loop but I guess this is just a safety check that is never 
supposed to match anyway so doesn't matter much I think which way it is 
done).

> +			cap = &data->capabilities[feat][cap_count];
> +			cap->group = group;
> +			cap->index = i;
> +			scnprintf(cap->name, sizeof(cap->name), "%s %d", dasharo_group_names[feat][group], i);

This too is beyond 100 chars.

After you've addressed these, please add:

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

> +			cap_count++;
> +		}
> +	}
> +	data->caps_found[feat] = cap_count;
> +}
> +
> +static int dasharo_probe(struct platform_device *pdev)
> +{
> +	struct dasharo_data *data;
> +	struct device *hwmon;
> +
> +	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +	data->pdev = pdev;
> +
> +	for (unsigned int i = 0; i < DASHARO_FEATURE_MAX; ++i)
> +		dasharo_fill_feature_caps(data, i);
> +
> +	hwmon = devm_hwmon_device_register_with_info(&pdev->dev, "dasharo_acpi", data,
> +						     &dasharo_hwmon_chip_info, NULL);
> +
> +	return PTR_ERR_OR_ZERO(hwmon);
> +}
> +
> +static const struct acpi_device_id dasharo_device_ids[] = {
> +	{"DSHR0001", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(acpi, dasharo_device_ids);
> +
> +static struct platform_driver dasharo_driver = {
> +	.driver = {
> +		.name = "dasharo-acpi",
> +		.acpi_match_table = dasharo_device_ids,
> +	},
> +	.probe = dasharo_probe,
> +};
> +module_platform_driver(dasharo_driver);
> +
> +MODULE_DESCRIPTION("Dasharo ACPI Driver");
> +MODULE_AUTHOR("Michał Kopeć <michal.kopec@3mdeb.com>");
> +MODULE_LICENSE("GPL");
> 

-- 
 i.