[PATCH v2 3/4] platform/x86: Add Lenovo Capability Data 01 WMI Driver

["Derek J. Clark" <derekjohn.clark@gmail.com>]

Adds lenovo-wmi-capdata01.c which provides a driver for the
LENOVO_CAPABILITY_DATA_01 WMI data block that comes on "Other Method"
enabled hardware. Provides an interface for querying if a given
attribute is supported by the hardware, as well as its default_value,
max_value, min_value, and step increment.

v2:
- Use devm_kzalloc to ensure driver can be instanced, remove global
  reference.
- Ensure reverse Christmas tree for all variable declarations.
- Remove extra whitespace.
- Use guard(mutex) in all mutex instances, global mutex.
- Use pr_fmt instead of adding the driver name to each pr_err.
- Remove noisy pr_info usage.
- Rename capdata_wmi to lenovo_wmi_cd01_priv and cd01_wmi to priv.
- Use list to get the lenovo_wmi_cd01_priv instance in
  lenovo_wmi_capdata01_get as none of the data provided by the macros
  that will use it can pass a member of the struct for use in
  container_of.

Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com>
---
 MAINTAINERS                                 |   1 +
 drivers/platform/x86/Kconfig                |  11 ++
 drivers/platform/x86/Makefile               |   1 +
 drivers/platform/x86/lenovo-wmi-capdata01.c | 131 ++++++++++++++++++++
 drivers/platform/x86/lenovo-wmi.h           |  20 +++
 5 files changed, 164 insertions(+)
 create mode 100644 drivers/platform/x86/lenovo-wmi-capdata01.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 8f8a6aec6b92..c9374c395905 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13038,6 +13038,7 @@ LENOVO WMI drivers
 M:	Derek J. Clark <derekjohn.clark@gmail.com>
 L:	platform-driver-x86@vger.kernel.org
 S:	Maintained
+F:	drivers/platform/x86/lenovo-wmi-capdata01.c
 F:	drivers/platform/x86/lenovo-wmi-gamezone.c
 F:	drivers/platform/x86/lenovo-wmi.h
 
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 9a6ac7fdec9f..a2c1ab47ad9e 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -470,6 +470,17 @@ config LENOVO_WMI_GAMEZONE
 	  To compile this driver as a module, choose M here: the module will
 	  be called lenovo_wmi_gamezone.
 
+config LENOVO_WMI_DATA01
+	tristate "Lenovo Legion WMI capability Data 01 Driver"
+	depends on ACPI_WMI
+	help
+	  Say Y here if you have a WMI aware Lenovo Legion device in the "Gaming Series"
+	  line of hardware. This interface is a dependency for exposing tunable power
+	  settings.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called lenovo_wmi_capdata01.
+
 config IDEAPAD_LAPTOP
 	tristate "Lenovo IdeaPad Laptop Extras"
 	depends on ACPI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 7cb29a480ed2..6c96cc3f3855 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_YOGABOOK)		+= lenovo-yogabook.o
 obj-$(CONFIG_YT2_1380)		+= lenovo-yoga-tab2-pro-1380-fastcharger.o
 obj-$(CONFIG_LENOVO_WMI_CAMERA)	+= lenovo-wmi-camera.o
 obj-$(CONFIG_LENOVO_WMI_GAMEZONE)	+= lenovo-wmi-gamezone.o
+obj-$(CONFIG_LENOVO_WMI_DATA01)	+= lenovo-wmi-capdata01.o
 
 # Intel
 obj-y				+= intel/
diff --git a/drivers/platform/x86/lenovo-wmi-capdata01.c b/drivers/platform/x86/lenovo-wmi-capdata01.c
new file mode 100644
index 000000000000..b10a6e4b320f
--- /dev/null
+++ b/drivers/platform/x86/lenovo-wmi-capdata01.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * LENOVO_CAPABILITY_DATA_01 WMI data block driver. This interface provides
+ * information on tunable attributes used by the "Other Method" WMI interface,
+ * including if it is supported by the hardware, the default_value, max_value,
+ * min_value, and step increment.
+ *
+ * Copyright(C) 2024 Derek J. Clark <derekjohn.clark@gmail.com>
+ */
+
+#include <linux/list.h>
+#include "lenovo-wmi.h"
+
+#define LENOVO_CAPABILITY_DATA_01_GUID "7A8F5407-CB67-4D6E-B547-39B3BE018154"
+
+static DEFINE_MUTEX(cd01_call_mutex);
+static DEFINE_MUTEX(cd01_list_mutex);
+static LIST_HEAD(cd01_wmi_list);
+
+static const struct wmi_device_id lenovo_wmi_capdata01_id_table[] = {
+	{ LENOVO_CAPABILITY_DATA_01_GUID, NULL },
+	{}
+};
+
+struct lenovo_wmi_cd01_priv {
+	struct wmi_device *wdev;
+	struct list_head list;
+};
+
+static inline struct lenovo_wmi_cd01_priv *get_first_wmi_priv(void)
+{
+	guard(mutex)(&cd01_list_mutex);
+	return list_first_entry_or_null(&cd01_wmi_list,
+					struct lenovo_wmi_cd01_priv, list);
+}
+
+int lenovo_wmi_capdata01_get(struct lenovo_wmi_attr_id attr_id,
+			     struct capability_data_01 *cap_data)
+{
+	u32 attribute_id = *(int *)&attr_id;
+	struct lenovo_wmi_cd01_priv *priv;
+	union acpi_object *ret_obj;
+	int instance_idx;
+	int count;
+
+	priv = get_first_wmi_priv();
+	if (!priv)
+		return -ENODEV;
+
+	guard(mutex)(&cd01_call_mutex);
+	count = wmidev_instance_count(priv->wdev);
+	pr_info("Got instance count: %u\n", count);
+
+	for (instance_idx = 0; instance_idx < count; instance_idx++) {
+		ret_obj = wmidev_block_query(priv->wdev, instance_idx);
+		if (!ret_obj) {
+			pr_err("WMI Data block query failed.\n");
+			continue;
+		}
+
+		if (ret_obj->type != ACPI_TYPE_BUFFER) {
+			pr_err("WMI Data block query returned wrong type.\n");
+			kfree(ret_obj);
+			continue;
+		}
+
+		if (ret_obj->buffer.length != sizeof(*cap_data)) {
+			pr_err("WMI Data block query returned wrong buffer length: %u vice expected %lu.\n",
+			       ret_obj->buffer.length, sizeof(*cap_data));
+			kfree(ret_obj);
+			continue;
+		}
+
+		memcpy(cap_data, ret_obj->buffer.pointer,
+		       ret_obj->buffer.length);
+		kfree(ret_obj);
+
+		if (cap_data->id != attribute_id)
+			continue;
+		break;
+	}
+
+	if (cap_data->id != attribute_id) {
+		pr_err("Unable to find capability data for attribute_id %x\n",
+		       attribute_id);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(lenovo_wmi_capdata01_get, "CAPDATA_WMI");
+
+static int lenovo_wmi_capdata01_probe(struct wmi_device *wdev,
+				      const void *context)
+
+{
+	struct lenovo_wmi_cd01_priv *priv;
+
+	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->wdev = wdev;
+
+	guard(mutex)(&cd01_list_mutex);
+	list_add_tail(&priv->list, &cd01_wmi_list);
+
+	return 0;
+}
+
+static void lenovo_wmi_capdata01_remove(struct wmi_device *wdev)
+{
+	struct lenovo_wmi_cd01_priv *priv = dev_get_drvdata(&wdev->dev);
+
+	guard(mutex)(&cd01_list_mutex);
+	list_del(&priv->list);
+}
+
+static struct wmi_driver lenovo_wmi_capdata01_driver = {
+	.driver = { .name = "lenovo_wmi_capdata01" },
+	.id_table = lenovo_wmi_capdata01_id_table,
+	.probe = lenovo_wmi_capdata01_probe,
+	.remove = lenovo_wmi_capdata01_remove,
+};
+
+module_wmi_driver(lenovo_wmi_capdata01_driver);
+
+MODULE_DEVICE_TABLE(wmi, lenovo_wmi_capdata01_id_table);
+MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@gmail.com>");
+MODULE_DESCRIPTION("Lenovo Capability Data 01 WMI Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/x86/lenovo-wmi.h b/drivers/platform/x86/lenovo-wmi.h
index 8a302c6c47cb..53cea84a956b 100644
--- a/drivers/platform/x86/lenovo-wmi.h
+++ b/drivers/platform/x86/lenovo-wmi.h
@@ -36,6 +36,22 @@ struct wmi_method_args {
 	u32 arg1;
 };
 
+struct lenovo_wmi_attr_id {
+	u32 mode_id : 16; /* Fan profile */
+	u32 feature_id : 8; /* Attribute (SPL/SPPT/...) */
+	u32 device_id : 8; /* CPU/GPU/... */
+} __packed;
+
+/* Data struct for LENOVO_CAPABILITY_DATA_01 */
+struct capability_data_01 {
+	u32 id;
+	u32 supported;
+	u32 default_value;
+	u32 step;
+	u32 min_value;
+	u32 max_value;
+};
+
 /* General Use functions */
 static int lenovo_wmidev_evaluate_method(struct wmi_device *wdev, u8 instance,
 					 u32 method_id, struct acpi_buffer *in,
@@ -102,4 +118,8 @@ int lenovo_wmidev_evaluate_method_1(struct wmi_device *wdev, u8 instance,
 					       0, retval);
 }
 
+/* LENOVO_CAPABILITY_DATA_01 exported functions */
+int lenovo_wmi_capdata01_get(struct lenovo_wmi_attr_id attr_id,
+			     struct capability_data_01 *cap_data);
+
 #endif /* !_LENOVO_WMI_H_ */
-- 
2.47.0