[PATCH v9 16/16] platform/x86: lenovo-wmi-capdata: Add debugfs file for dumping capdata

Derek J. Clark
2026-04-11T16:23:49Z

From: Rong Zhang <i@rong.moe>

The Lenovo GameZone/Other interfaces have some delicate divergences
among different devices. When making a bug report or adding support for
new devices/interfaces, capdata is the most important information to
cross-check with.

Add a debugfs file (lenovo_wmi/<device_name>/capdata), so that users can
dump capdata and include it in their reports.

Since `struct capdata01' is just an extension to `struct capdata00',
also converts the former to include the latter anonymously
(-fms-extensions, since v6.19). In this manner type casting won't be
confusing.

Tested-by: Kurt Borja <kuurtb@gmail.com>
Signed-off-by: Rong Zhang <i@rong.moe>
Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com>
---
drivers/platform/x86/lenovo/Kconfig | 1 +
drivers/platform/x86/lenovo/wmi-capdata.c | 120 ++++++++++++++++++++++
drivers/platform/x86/lenovo/wmi-capdata.h | 4 +-
3 files changed, 122 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/lenovo/Kconfig b/drivers/platform/x86/lenovo/Kconfig
index b9a5d18caa1e..4443f40ef8aa 100644
--- a/drivers/platform/x86/lenovo/Kconfig
+++ b/drivers/platform/x86/lenovo/Kconfig
@@ -236,6 +236,7 @@ config YT2_1380
config LENOVO_WMI_CAPDATA
tristate
depends on ACPI_WMI
+ depends on LENOVO_WMI_HELPERS

config LENOVO_WMI_EVENTS
tristate
diff --git a/drivers/platform/x86/lenovo/wmi-capdata.c b/drivers/platform/x86/lenovo/wmi-capdata.c
index 169665be4dcf..b5e2c16d638f 100644
--- a/drivers/platform/x86/lenovo/wmi-capdata.c
+++ b/drivers/platform/x86/lenovo/wmi-capdata.c
@@ -31,6 +31,7 @@
#include <linux/cleanup.h>
#include <linux/component.h>
#include <linux/container_of.h>
+#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/dev_printk.h>
#include <linux/err.h>
@@ -42,6 +43,7 @@
#include <linux/mutex_types.h>
#include <linux/notifier.h>
#include <linux/overflow.h>
+#include <linux/seq_file.h>
#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/wmi.h>
@@ -88,6 +90,7 @@ struct lwmi_cd_priv {
struct notifier_block acpi_nb; /* ACPI events */
struct wmi_device *wdev;
struct cd_list *list;
+ struct dentry *debugfs_dir;

/*
* A capdata device may be a component master of another capdata device.
@@ -118,6 +121,8 @@ struct cd_list {

static struct wmi_driver lwmi_cd_driver;

+/* ======== Device components ======== */
+
/**
* lwmi_cd_match() - Match rule for the master driver.
* @dev: Pointer to the capability data parent device.
@@ -471,6 +476,116 @@ EXPORT_SYMBOL_NS_GPL(lwmi_cd01_get_data, "LENOVO_WMI_CAPDATA");
DEF_LWMI_CDXX_GET_DATA(cd_fan, LENOVO_FAN_TEST_DATA, struct capdata_fan);
EXPORT_SYMBOL_NS_GPL(lwmi_cd_fan_get_data, "LENOVO_WMI_CAPDATA");

+/* ======== debugfs ======== */
+
+/**
+ * lwmi_cd00_show() - Dump capdata00
+ * @s: Pointer to seq_file where the capdata00 is dumped.
+ * @cd00: Pointer to a capdata00 struct to be dumped.
+ */
+static void lwmi_cd00_show(struct seq_file *s, struct capdata00 *cd00)
+{
+ u8 dev = FIELD_GET(LWMI_ATTR_DEV_ID_MASK, cd00->id);
+ u8 feat = FIELD_GET(LWMI_ATTR_FEAT_ID_MASK, cd00->id);
+ u8 mode = FIELD_GET(LWMI_ATTR_MODE_ID_MASK, cd00->id);
+ u8 type = FIELD_GET(LWMI_ATTR_TYPE_ID_MASK, cd00->id);
+ bool extra = cd00->supported & ~(LWMI_SUPP_GET | LWMI_SUPP_SET | LWMI_SUPP_VALID);
+ bool get = cd00->supported & LWMI_SUPP_GET;
+ bool set = cd00->supported & LWMI_SUPP_SET;
+ bool valid = cd00->supported & LWMI_SUPP_VALID;
+
+ seq_printf(s, " id: 0x%08x [dev: %2u, feat: %2u, mode: %2u, type: %2u]\n",
+ cd00->id, dev, feat, mode, type);
+
+ seq_printf(s, " supported: 0x%08x [%c%c%c%c]\n", cd00->supported,
+ extra ? '+' : ' ',
+ get ? 'R' : ' ',
+ set ? 'W' : ' ',
+ valid ? 'V' : ' ');
+
+ seq_printf(s, " default_value: %u\n", cd00->default_value);
+}
+
+/**
+ * lwmi_cd01_show() - Dump capdata01
+ * @s: Pointer to seq_file where the capdata01 is dumped.
+ * @cd01: Pointer to a capdata01 struct to be dumped.
+ */
+static void lwmi_cd01_show(struct seq_file *s, struct capdata01 *cd01)
+{
+ /* capdata01 is an extension to capdata00. */
+ lwmi_cd00_show(s, (struct capdata00 *)cd01);
+
+ seq_printf(s, " step: %u\n", cd01->step);
+ seq_printf(s, " min_value: %u\n", cd01->min_value);
+ seq_printf(s, " max_value: %u\n", cd01->max_value);
+}
+
+/**
+ * lwmi_cd_fan_show() - Dump capdata_fan
+ * @s: Pointer to seq_file where the capdata_fan is dumped.
+ * @cd_fan: Pointer to a capdata_fan struct to be dumped.
+ */
+static void lwmi_cd_fan_show(struct seq_file *s, struct capdata_fan *cd_fan)
+{
+ seq_printf(s, " id: %u\n", cd_fan->id);
+ seq_printf(s, " min_rpm: %u\n", cd_fan->min_rpm);
+ seq_printf(s, " max_rpm: %u\n", cd_fan->max_rpm);
+}
+
+/**
+ * lwmi_cd_debugfs_show() - Dump capability data to debugfs
+ * @s: Pointer to seq_file where the capability data is dumped.
+ * @data: unused.
+ *
+ * Return: 0
+ */
+static int lwmi_cd_debugfs_show(struct seq_file *s, void *data)
+{
+ struct lwmi_cd_priv *priv = s->private;
+ u8 idx;
+
+ guard(mutex)(&priv->list->list_mutex);
+
+ /* lwmi_cd_alloc() ensured priv->list->type must be a valid type. */
+ for (idx = 0; idx < priv->list->count; idx++) {
+ seq_printf(s, "%s[%u]:\n", lwmi_cd_table[priv->list->type].name, idx);
+
+ if (priv->list->type == LENOVO_CAPABILITY_DATA_00)
+ lwmi_cd00_show(s, &priv->list->cd00[idx]);
+ else if (priv->list->type == LENOVO_CAPABILITY_DATA_01)
+ lwmi_cd01_show(s, &priv->list->cd01[idx]);
+ else if (priv->list->type == LENOVO_FAN_TEST_DATA)
+ lwmi_cd_fan_show(s, &priv->list->cd_fan[idx]);
+ }
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(lwmi_cd_debugfs);
+
+/**
+ * lwmi_cd_debugfs_add() - Create debugfs directory and files for a device
+ * @priv: lenovo-wmi-capdata driver data.
+ */
+static void lwmi_cd_debugfs_add(struct lwmi_cd_priv *priv)
+{
+ priv->debugfs_dir = lwmi_debugfs_create_dir(priv->wdev);
+
+ debugfs_create_file("capdata", 0444, priv->debugfs_dir, priv, &lwmi_cd_debugfs_fops);
+}
+
+/**
+ * lwmi_cd_debugfs_remove() - Remove debugfs directory for a device
+ * @priv: lenovo-wmi-capdata driver data.
+ */
+static void lwmi_cd_debugfs_remove(struct lwmi_cd_priv *priv)
+{
+ debugfs_remove_recursive(priv->debugfs_dir);
+ priv->debugfs_dir = NULL;
+}
+
+/* ======== WMI interface ======== */
+
/**
* lwmi_cd_cache() - Cache all WMI data block information
* @priv: lenovo-wmi-capdata driver data.
@@ -773,6 +888,8 @@ static int lwmi_cd_probe(struct wmi_device *wdev, const void *context)
dev_err(&wdev->dev, "failed to register %s: %d\n",
info->name, ret);
} else {
+ lwmi_cd_debugfs_add(priv);
+
dev_dbg(&wdev->dev, "registered %s with %u items\n",
info->name, priv->list->count);
}
@@ -783,6 +900,8 @@ static void lwmi_cd_remove(struct wmi_device *wdev)
{
struct lwmi_cd_priv *priv = dev_get_drvdata(&wdev->dev);

+ lwmi_cd_debugfs_remove(priv);
+
switch (priv->list->type) {
case LENOVO_CAPABILITY_DATA_00:
lwmi_cd_sub_master_del(priv);
@@ -822,6 +941,7 @@ static struct wmi_driver lwmi_cd_driver = {

module_wmi_driver(lwmi_cd_driver);

+MODULE_IMPORT_NS("LENOVO_WMI_HELPERS");
MODULE_DEVICE_TABLE(wmi, lwmi_cd_id_table);
MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@gmail.com>");
MODULE_AUTHOR("Rong Zhang <i@rong.moe>");
diff --git a/drivers/platform/x86/lenovo/wmi-capdata.h b/drivers/platform/x86/lenovo/wmi-capdata.h
index e0a30f2c0c87..0df3ae534ed5 100644
--- a/drivers/platform/x86/lenovo/wmi-capdata.h
+++ b/drivers/platform/x86/lenovo/wmi-capdata.h
@@ -38,9 +38,7 @@ struct capdata00 {
};

struct capdata01 {
- u32 id;
- u32 supported;
- u32 default_value;
+ struct capdata00;
u32 step;
u32 min_value;
u32 max_value;
--
2.53.0