[PATCH v2] platform/x86: lenovo-wmi-other: Deconflict battery with thinkpad_acpi

[Aaron Ma <aaron.ma@canonical.com>]

ThinkPads expose battery charge thresholds and charge_behaviour through
thinkpad_acpi's ACPI battery hook using raw sysfs attribute groups. The
Lenovo WMI "Other Mode" driver also registers a power_supply_ext for
charge_behaviour and charge_types on systems advertising those WMI
capabilities.

When lenovo-wmi-other registers first, thinkpad_acpi fails to create a
duplicate charge_behaviour sysfs attribute and unregisters its battery
extension. Conversely, registering or updating any power_supply_ext on
the same battery runs sysfs_update_groups(), which removes standard
power-supply attributes not owned by power_supply_core and wipes out
thinkpad_acpi's charge_control_start_threshold,
charge_control_end_threshold, and charge_behaviour files.

Deconflict both ideapad_laptop (VPC2004 with GBMD and SBMC) and
thinkpad_acpi (LEN0268, LEN0068, or IBM0068 with BDSG and BICG) via a
table check when the corresponding driver is enabled in Kconfig, and
update the force_load_psy_ext description accordingly.

Fixes: 9ca8fc065b88b ("platform/x86: lenovo-wmi-other: Add WMI battery charge limiting")
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
---
Changes in v2:
- Consolidate IdeaPad and ThinkPad deconfliction into a table of ACPI
  device IDs, method pairs, and driver configuration checks, as suggested
  by Derek J. Clark.
- Check GBMD and SBMC for IdeaPads, and BDSG and BICG for ThinkPads,
  instead of relying only on ThinkPad ACPI device presence.
- Check whether the corresponding driver is enabled before looking up
  its ACPI device, including for ideapad_laptop.
- Update the force_load_psy_ext description to cover both drivers.

v1: https://lore.kernel.org/platform-driver-x86/20261111083529.727285-1-aaron.ma@canonical.com/

 drivers/platform/x86/lenovo/wmi-other.c | 51 ++++++++++++++++++-------
 1 file changed, 38 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/x86/lenovo/wmi-other.c b/drivers/platform/x86/lenovo/wmi-other.c
index bd64e7b44669d..14b2c3f4cc7ae 100644
--- a/drivers/platform/x86/lenovo/wmi-other.c
+++ b/drivers/platform/x86/lenovo/wmi-other.c
@@ -189,10 +189,10 @@ MODULE_PARM_DESC(relax_fan_constraint,
 static bool force_load_psy_ext;
 module_param(force_load_psy_ext, bool, 0444);
 MODULE_PARM_DESC(force_load_psy_ext,
-	"This option will skip checking if the ideapad_laptop driver will conflict "
+	"This option will skip checking if the ideapad_laptop or thinkpad_acpi driver will conflict "
 	"with adding an extension to set the battery charge behavior and battery charge "
 	"control end threshold. It will also skip checking if the BIOS reports that "
-	"those features are fully supported. It is recommended to blacklist the ideapad "
+	"those features are fully supported. It is recommended to blacklist the conflicting "
 	"driver before using this option.");
 
 /* ======== HWMON (component: lenovo-wmi-capdata 00 & fan) ======== */
@@ -905,17 +905,32 @@ static acpi_status lwmi_acpi_match(acpi_handle handle, u32 lvl,
 	return AE_CTRL_TERMINATE;
 }
 
+struct lwmi_psy_deconflict {
+	const char *hid;
+	char * const *methods;
+	bool driver_enabled;
+};
+
+static char * const lwmi_ideapad_psy_methods[] = { "GBMD", "SBMC" };
+static char * const lwmi_thinkpad_psy_methods[] = { "BDSG", "BICG" };
+
+static const struct lwmi_psy_deconflict lwmi_psy_deconflict_list[] = {
+	{ "VPC2004", lwmi_ideapad_psy_methods, IS_ENABLED(CONFIG_IDEAPAD_LAPTOP) },
+	{ "LEN0268", lwmi_thinkpad_psy_methods, IS_ENABLED(CONFIG_THINKPAD_ACPI) },
+	{ "LEN0068", lwmi_thinkpad_psy_methods, IS_ENABLED(CONFIG_THINKPAD_ACPI) },
+	{ "IBM0068", lwmi_thinkpad_psy_methods, IS_ENABLED(CONFIG_THINKPAD_ACPI) },
+};
+
 /**
  * lwmi_om_psy_ext_init() - Hooks power supply extension to device battery
  * @priv: Pointer to the lwmi_om_priv drvdata.
  *
- * Checks if the ideapad_laptop driver is going to manage charge attributes first,
- * then if not, hooks the battery to our WMI methods if they are supported.
+ * Checks if the ideapad_laptop or thinkpad_acpi driver is going to manage
+ * charge attributes first, then if not, hooks the battery to our WMI methods
+ * if they are supported.
  */
 static void lwmi_om_psy_ext_init(struct lwmi_om_priv *priv)
 {
-	static const char * const ideapad_hid = "VPC2004";
-	acpi_handle handle = NULL;
 	unsigned int props = 0;
 	int ret;
 
@@ -928,14 +943,24 @@ static void lwmi_om_psy_ext_init(struct lwmi_om_priv *priv)
 	if (force_load_psy_ext)
 		goto load_psy_ext;
 
-	/* Deconflict ideapad_laptop driver */
-	ret = acpi_get_devices(ideapad_hid, lwmi_acpi_match, &handle, NULL);
-	if (ret)
-		return;
+	for (unsigned int i = 0; i < ARRAY_SIZE(lwmi_psy_deconflict_list); i++) {
+		const struct lwmi_psy_deconflict *entry = &lwmi_psy_deconflict_list[i];
+		acpi_handle handle = NULL;
 
-	if (handle && acpi_has_method(handle, "GBMD") && acpi_has_method(handle, "SBMC")) {
-		dev_dbg(&priv->wdev->dev, "ideapad_laptop driver manages battery for device\n");
-		return;
+		if (!entry->driver_enabled)
+			continue;
+
+		ret = acpi_get_devices(entry->hid, lwmi_acpi_match, &handle, NULL);
+		if (ret || !handle)
+			continue;
+
+		if (acpi_has_method(handle, entry->methods[0]) &&
+		    acpi_has_method(handle, entry->methods[1])) {
+			dev_dbg(&priv->wdev->dev,
+				"ACPI device %s manages battery for device\n",
+				entry->hid);
+			return;
+		}
 	}
 
 load_psy_ext:
-- 
2.53.0