[PATCH 6.10 17/22] platform/x86: ideapad-laptop: introduce a generic notification chain

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gergo Koteles <soyer@irl.hu>

[ Upstream commit 613e3900c24bb1379d994f44d75d31c3223cc263 ]

There are several cases where a notification chain can simplify Lenovo
WMI drivers.

Add a generic notification chain into ideapad-laptop.

Signed-off-by: Gergo Koteles <soyer@irl.hu>
Link: https://lore.kernel.org/r/c5a43efae8a32bd034c3d19c0a686941347575a7.1721898747.git.soyer@irl.hu
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Stable-dep-of: 7cc06e729460 ("platform/x86: ideapad-laptop: add a mutex to synchronize VPC commands")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/x86/ideapad-laptop.c | 37 +++++++++++++++++++++++++++
 drivers/platform/x86/ideapad-laptop.h |  5 ++++
 2 files changed, 42 insertions(+)

diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
index fcf13d88fd6ed..38d98ee558d32 100644
--- a/drivers/platform/x86/ideapad-laptop.c
+++ b/drivers/platform/x86/ideapad-laptop.c
@@ -1599,6 +1599,39 @@ static void ideapad_sync_touchpad_state(struct ideapad_private *priv, bool send_
 	priv->r_touchpad_val = value;
 }
 
+static int ideapad_laptop_nb_notify(struct notifier_block *nb,
+				    unsigned long action, void *data)
+{
+	switch (action) {
+	}
+
+	return 0;
+}
+
+static struct notifier_block ideapad_laptop_notifier = {
+	.notifier_call = ideapad_laptop_nb_notify,
+};
+
+static BLOCKING_NOTIFIER_HEAD(ideapad_laptop_chain_head);
+
+int ideapad_laptop_register_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&ideapad_laptop_chain_head, nb);
+}
+EXPORT_SYMBOL_NS_GPL(ideapad_laptop_register_notifier, IDEAPAD_LAPTOP);
+
+int ideapad_laptop_unregister_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&ideapad_laptop_chain_head, nb);
+}
+EXPORT_SYMBOL_NS_GPL(ideapad_laptop_unregister_notifier, IDEAPAD_LAPTOP);
+
+void ideapad_laptop_call_notifier(unsigned long action, void *data)
+{
+	blocking_notifier_call_chain(&ideapad_laptop_chain_head, action, data);
+}
+EXPORT_SYMBOL_NS_GPL(ideapad_laptop_call_notifier, IDEAPAD_LAPTOP);
+
 static void ideapad_acpi_notify(acpi_handle handle, u32 event, void *data)
 {
 	struct ideapad_private *priv = data;
@@ -1983,6 +2016,8 @@ static int ideapad_acpi_add(struct platform_device *pdev)
 	if (err)
 		goto shared_init_failed;
 
+	ideapad_laptop_register_notifier(&ideapad_laptop_notifier);
+
 	return 0;
 
 shared_init_failed:
@@ -2015,6 +2050,8 @@ static void ideapad_acpi_remove(struct platform_device *pdev)
 	struct ideapad_private *priv = dev_get_drvdata(&pdev->dev);
 	int i;
 
+	ideapad_laptop_unregister_notifier(&ideapad_laptop_notifier);
+
 	ideapad_shared_exit(priv);
 
 	acpi_remove_notify_handler(priv->adev->handle,
diff --git a/drivers/platform/x86/ideapad-laptop.h b/drivers/platform/x86/ideapad-laptop.h
index 4498a96de5976..3eb0dcd6bf7ba 100644
--- a/drivers/platform/x86/ideapad-laptop.h
+++ b/drivers/platform/x86/ideapad-laptop.h
@@ -12,6 +12,11 @@
 #include <linux/acpi.h>
 #include <linux/jiffies.h>
 #include <linux/errno.h>
+#include <linux/notifier.h>
+
+int ideapad_laptop_register_notifier(struct notifier_block *nb);
+int ideapad_laptop_unregister_notifier(struct notifier_block *nb);
+void ideapad_laptop_call_notifier(unsigned long action, void *data);
 
 enum {
 	VPCCMD_R_VPC1 = 0x10,
-- 
2.43.0