Re: [PATCH v11] platform/x86: add lenovo wmi camera button driver
From: Armin Wolf
Date: Fri Mar 22 2024 - 14:49:23 EST
Am 22.03.24 um 17:47 schrieb Kuppuswamy Sathyanarayanan:
On 3/22/24 7:39 AM, Ilpo Järvinen wrote:
On Fri, 22 Mar 2024, Kuppuswamy Sathyanarayanan wrote:
On 3/21/24 11:47 PM, Ai Chao wrote:
Add lenovo generic wmi driver to support camera button.
The Camera button is a GPIO device. This driver receives ACPI notifyi
when the camera button is switched on/off. This driver is used in
Lenovo A70, it is a Computer integrated machine.
Signed-off-by: Ai Chao <aichao@xxxxxxxxxx>
---
v11: remove input_unregister_device.
v10: Add lenovo_wmi_remove and mutex_destroy.
v9: Add mutex for wmi notify.
v8: Dev_deb convert to dev_err.
v7: Add dev_dbg and remove unused dev in struct.
v6: Modify SW_CAMERA_LENS_COVER to KEY_CAMERA_ACCESS_ENABLE/KEY_CAMERA_ACCESS_DISABLE.
v5: Remove camera button groups, modify KEY_CAMERA to SW_CAMERA_LENS_COVER.
v4: Remove lenovo_wmi_input_setup, move camera_mode into struct lenovo_wmi_priv.
v3: Remove lenovo_wmi_remove function.
v2: Adjust GPL v2 to GPL, adjust sprintf to sysfs_emit.
drivers/platform/x86/Kconfig | 12 +++
drivers/platform/x86/Makefile | 1 +
drivers/platform/x86/lenovo-wmi-camera.c | 126 +++++++++++++++++++++++
3 files changed, 139 insertions(+)
create mode 100644 drivers/platform/x86/lenovo-wmi-camera.c
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index bdd302274b9a..9506a455b547 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1001,6 +1001,18 @@ config INSPUR_PLATFORM_PROFILE
To compile this driver as a module, choose M here: the module
will be called inspur-platform-profile.
+config LENOVO_WMI_CAMERA
+ tristate "Lenovo WMI Camera Button driver"
+ depends on ACPI_WMI
+ depends on INPUT
+ help
+ This driver provides support for Lenovo camera button. The Camera
+ button is a GPIO device. This driver receives ACPI notify when the
+ camera button is switched on/off.
+
+ To compile this driver as a module, choose M here: the module
+ will be called lenovo-wmi-camera.
+
source "drivers/platform/x86/x86-android-tablets/Kconfig"
config FW_ATTR_CLASS
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 1de432e8861e..217e94d7c877 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -66,6 +66,7 @@ obj-$(CONFIG_SENSORS_HDAPS) += hdaps.o
obj-$(CONFIG_THINKPAD_ACPI) += thinkpad_acpi.o
obj-$(CONFIG_THINKPAD_LMI) += think-lmi.o
obj-$(CONFIG_YOGABOOK) += lenovo-yogabook.o
+obj-$(CONFIG_LENOVO_WMI_CAMERA) += lenovo-wmi-camera.o
# Intel
obj-y += intel/
diff --git a/drivers/platform/x86/lenovo-wmi-camera.c b/drivers/platform/x86/lenovo-wmi-camera.c
new file mode 100644
index 000000000000..fda936e2f37c
--- /dev/null
+++ b/drivers/platform/x86/lenovo-wmi-camera.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Lenovo WMI Camera Button Driver
+ *
+ * Author: Ai Chao <aichao@xxxxxxxxxx>
+ * Copyright (C) 2024 KylinSoft Corporation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/wmi.h>
+
+#define WMI_LENOVO_CAMERABUTTON_EVENT_GUID "50C76F1F-D8E4-D895-0A3D-62F4EA400013"
+
+struct lenovo_wmi_priv {
+ struct input_dev *idev;
+ struct mutex notify_lock; /* lenovo wmi camera button notify lock */
+};
+
+enum {
+ SW_CAMERA_OFF = 0,
+ SW_CAMERA_ON = 1,
+};
+
+static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
+{
+ struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
+ unsigned int keycode;
+ u8 camera_mode;
+
+ if (obj->type != ACPI_TYPE_BUFFER) {
+ dev_err(&wdev->dev, "Bad response type %u\n", obj->type);
+ return;
+ }
+
+ if (obj->buffer.length != 1) {
+ dev_err(&wdev->dev, "Invalid buffer length %u\n", obj->buffer.length);
+ return;
+ }
+
+ /* obj->buffer.pointer[0] is camera mode:
+ * 0 camera close
+ * 1 camera open
+ */
+ camera_mode = obj->buffer.pointer[0];
+ if (camera_mode > SW_CAMERA_ON) {
+ dev_err(&wdev->dev, "Unknown camera mode %u\n", camera_mode);
+ return;
+ }
+
+ mutex_lock(&priv->notify_lock);
+
+ keycode = (camera_mode == SW_CAMERA_ON ?
+ KEY_CAMERA_ACCESS_ENABLE : KEY_CAMERA_ACCESS_DISABLE);
+ input_report_key(priv->idev, keycode, 1);
+ input_sync(priv->idev);
+ input_report_key(priv->idev, keycode, 0);
+ input_sync(priv->idev);
+
+ mutex_unlock(&priv->notify_lock);
+}
+
+static int lenovo_wmi_probe(struct wmi_device *wdev, const void *context)
+{
+ struct lenovo_wmi_priv *priv;
+ int ret;
+
+ priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ dev_set_drvdata(&wdev->dev, priv);
+
+ priv->idev = devm_input_allocate_device(&wdev->dev);
+ if (!priv->idev)
+ return -ENOMEM;
+
+ priv->idev->name = "Lenovo WMI Camera Button";
+ priv->idev->phys = "wmi/input0";
+ priv->idev->id.bustype = BUS_HOST;
+ priv->idev->dev.parent = &wdev->dev;
+ input_set_capability(priv->idev, EV_KEY, KEY_CAMERA_ACCESS_ENABLE);
+ input_set_capability(priv->idev, EV_KEY, KEY_CAMERA_ACCESS_DISABLE);
+
+ ret = input_register_device(priv->idev);
+ if (ret)
+ return ret;
+
+ mutex_init(&priv->notify_lock);
+
+ return 0;
+}
+
+static void lenovo_wmi_remove(struct wmi_device *wdev)
+{
+ struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
+
+ mutex_destroy(&priv->notify_lock);
Do you really need to call mutex_destroy() during the module unload?
I don't think kernel allocates any memory during mutex_init() that needs
be freed.
Is all debug code going to be happy if it's not called?
I am not aware of any issue. Do you have any details about it?
From the comments, it looks like mutex_destroy() is used to mark a
mutex unusable. Not sure why we need to mark a device priv lock
unusable during the unload process.
Hi,
AFAIK calling mutex_destroy() allows the lock debugging code to catch
attempts to access the mutex afterwards, so this would allow us to spot
such issues when enabling lock debugging.
For the whole driver:
Reviewed-by: Armin Wolf <W_Armin@xxxxxx>