Re: [PATCH v8] platform/x86: add lenovo wmi camera button driver
From: Armin Wolf
Date: Fri Mar 15 2024 - 13:27:16 EST
Am 15.03.24 um 12:51 schrieb Ilpo Järvinen:
On Thu, 14 Mar 2024, Armin Wolf wrote:
Am 14.03.24 um 06:03 schrieb Ai Chao:
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>
---
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 | 108 +++++++++++++++++++++++
3 files changed, 121 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..f83e3ccd9189
--- /dev/null
+++ b/drivers/platform/x86/lenovo-wmi-camera.c
@@ -0,0 +1,108 @@
+// 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/wmi.h>
+
+#define WMI_LENOVO_CAMERABUTTON_EVENT_GUID
"50C76F1F-D8E4-D895-0A3D-62F4EA400013"
+
+struct lenovo_wmi_priv {
+ struct input_dev *idev;
+};
+
+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);
+ 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;
+ }
+
+ if (camera_mode == SW_CAMERA_ON) {
+ input_report_key(priv->idev, KEY_CAMERA_ACCESS_ENABLE, 1);
+ input_sync(priv->idev);
+ input_report_key(priv->idev, KEY_CAMERA_ACCESS_ENABLE, 0);
+ } else {
+ input_report_key(priv->idev, KEY_CAMERA_ACCESS_DISABLE, 1);
+ input_sync(priv->idev);
+ input_report_key(priv->idev, KEY_CAMERA_ACCESS_DISABLE, 0);
+ }
While not exactly wrong the if seems unnecessary, you could do:
unsigned int keycode;
...
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);
+}
Armin,
I tried to figure out the concurrency rules for the WMI notify handler but
came up basically nothing. I suppose it boils down on ACPI notify handling
and I couldn't find useful documentation about that either. :-/
Could you perhaps add this information into WMI documentation?
As far as i know, the ACPI notify handlers can be scheduled concurrently on all CPUs,
see https://lore.kernel.org/all/7617703.EvYhyI6sBW@kreacher/ for details.
I will add a short note about this to the WMI driver guide which i plan to upstream
soon (after the EC handler stuff is finished).
Thanks,
Armin Wolf