[PATCH v12 16/16] platform/x86: lenovo-wmi-capdata: Add debugfs file for dumping capdata

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

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 convert the former to include the latter anonymously
(-fms-extensions, since v6.19). This is declared as a union in the
capdata01 struct, with both the anonymous declaration and as a named
member to avoid type casting when passing just the capdata00 struct
pointer.

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>
---
v12:
  - Make capdata00 a union of an anonymous member and a named member of
    capdata01 to avoid casting when capdata00 is accessed directly.
---
 drivers/platform/x86/lenovo/Kconfig       |   1 +
 drivers/platform/x86/lenovo/wmi-capdata.c | 120 ++++++++++++++++++++++
 drivers/platform/x86/lenovo/wmi-capdata.h |   7 +-
 3 files changed, 125 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..63561af734c8 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, &cd01->cd00);
+
+	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 a49229cec245..92098aeeee84 100644
--- a/drivers/platform/x86/lenovo/wmi-capdata.h
+++ b/drivers/platform/x86/lenovo/wmi-capdata.h
@@ -38,9 +38,10 @@ struct capdata00 {
 };
 
 struct capdata01 {
-	u32 id;
-	u32 supported;
-	u32 default_value;
+	union {
+		struct capdata00;
+		struct capdata00 cd00;
+	};
 	u32 step;
 	u32 min_value;
 	u32 max_value;
-- 
2.53.0