[PATCH v2] platform/x86: Add WMI driver for Redmibook keyboard.

[PATCH v2] platform/x86: Add WMI driver for Redmibook keyboard.

[Gladyshev Ilya]

This driver implements support for various Fn keys (like Cut) and Xiaomi
specific AI button.

Signed-off-by: Gladyshev Ilya <foxido@foxido.dev>
---

Changes from v1:
- Use sparse-keymap instead of manual matching
- Fix GUID case so it actually autoloads
- Other fixes from v1 review

Link to v1: https://lore.kernel.org/platform-driver-x86/20250727223516.29244-1-foxido@foxido.dev/

---
 MAINTAINERS                      |   6 ++
 drivers/platform/x86/Kconfig     |  11 +++
 drivers/platform/x86/Makefile    |   1 +
 drivers/platform/x86/redmi-wmi.c | 129 +++++++++++++++++++++++++++++++
 4 files changed, 147 insertions(+)
 create mode 100644 drivers/platform/x86/redmi-wmi.c

diff --git a/MAINTAINERS b/MAINTAINERS
index c0b444e5fd5a..eb25fb10e751 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20965,6 +20965,12 @@ S:	Maintained
 T:	git https://github.com/pkshih/rtw.git
 F:	drivers/net/wireless/realtek/rtw89/
 
+REDMIBOOK WMI DRIVERS
+M:	Gladyshev Ilya <foxido@foxido.dev>
+L:	platform-driver-x86@vger.kernel.org
+S:	Maintained
+F:	drivers/platform/x86/redmi-wmi.c
+
 REDPINE WIRELESS DRIVER
 L:	linux-wireless@vger.kernel.org
 S:	Orphan
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index e5cbd58a99f3..3c570cb398d3 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -109,6 +109,17 @@ config XIAOMI_WMI
 	  To compile this driver as a module, choose M here: the module will
 	  be called xiaomi-wmi.
 
+config REDMI_WMI
+	tristate "Redmibook WMI key driver"
+	depends on ACPI_WMI
+	depends on INPUT
+	help
+	  Say Y here if you want support for WMI-based hotkey events on
+	  Xiaomi Redmibook devices.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called redmi-wmi.
+
 config GIGABYTE_WMI
 	tristate "Gigabyte WMI temperature driver"
 	depends on ACPI_WMI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index bea87a85ae75..406dd0807ba7 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_HUAWEI_WMI)		+= huawei-wmi.o
 obj-$(CONFIG_MXM_WMI)			+= mxm-wmi.o
 obj-$(CONFIG_NVIDIA_WMI_EC_BACKLIGHT)	+= nvidia-wmi-ec-backlight.o
 obj-$(CONFIG_XIAOMI_WMI)		+= xiaomi-wmi.o
+obj-$(CONFIG_REDMI_WMI)			+= redmi-wmi.o
 obj-$(CONFIG_GIGABYTE_WMI)		+= gigabyte-wmi.o
 
 # Acer
diff --git a/drivers/platform/x86/redmi-wmi.c b/drivers/platform/x86/redmi-wmi.c
new file mode 100644
index 000000000000..732688fb94e0
--- /dev/null
+++ b/drivers/platform/x86/redmi-wmi.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/* WMI driver for Xiaomi Redmibooks */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/input/sparse-keymap.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/unaligned.h>
+#include <linux/wmi.h>
+
+#include <uapi/linux/input-event-codes.h>
+
+#define WMI_REDMIBOOK_KEYBOARD_EVENT_GUID "46C93E13-EE9B-4262-8488-563BCA757FEF"
+
+#define AI_KEY_VALUE_MASK 0x00000100
+
+static const struct key_entry redmi_wmi_keymap[] = {
+	{KE_KEY, 0x00000201,	{KEY_SELECTIVE_SCREENSHOT}},
+	{KE_KEY, 0x00000301,	{KEY_ALL_APPLICATIONS}},
+	{KE_KEY, 0x00001b01,	{KEY_SETUP}},
+
+	/* AI button has code for each position */
+	{KE_KEY, 0x00011801,	{KEY_ASSISTANT}},
+	{KE_KEY, 0x00011901,	{KEY_ASSISTANT}},
+
+	/* Keyboard backlight */
+	{KE_IGNORE, 0x00000501, {}},
+	{KE_IGNORE, 0x00800501, {}},
+	{KE_IGNORE, 0x00050501, {}},
+	{KE_IGNORE, 0x000a0501, {}},
+
+	{KE_END}
+};
+
+struct redmi_wmi {
+	struct input_dev *input_dev;
+	/* Protects the key event sequence */
+	struct mutex key_lock;
+};
+
+static int redmi_wmi_probe(struct wmi_device *wdev, const void *context)
+{
+	struct redmi_wmi *data;
+	int err;
+
+	/* Init dev */
+	data = devm_kzalloc(&wdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	dev_set_drvdata(&wdev->dev, data);
+
+	err = devm_mutex_init(&wdev->dev, &data->key_lock);
+	if (err)
+		return err;
+
+	/* Setup input device */
+	data->input_dev = devm_input_allocate_device(&wdev->dev);
+	if (!data->input_dev)
+		return -ENOMEM;
+	data->input_dev->name = "Redmibook WMI keys";
+	data->input_dev->phys = "wmi/input0";
+
+	err = sparse_keymap_setup(data->input_dev, redmi_wmi_keymap, NULL);
+	if (err)
+		return err;
+
+	return input_register_device(data->input_dev);
+}
+
+static void redmi_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
+{
+	struct redmi_wmi *data = dev_get_drvdata(&wdev->dev);
+	int value = 1;
+	bool autorelease = true;
+
+	if (obj->type != ACPI_TYPE_BUFFER) {
+		dev_err(&wdev->dev, "Bad response type %u\n", obj->type);
+		return;
+	}
+
+	if (obj->buffer.length != 32) {
+		dev_err(&wdev->dev, "Invalid buffer length %u\n", obj->buffer.length);
+		return;
+	}
+
+	/* For linearizability */
+	guard(mutex)(&data->key_lock);
+
+	u32 payload = get_unaligned_le32(obj->buffer.pointer);
+	struct key_entry *entry = sparse_keymap_entry_from_scancode(data->input_dev, payload);
+
+	if (!entry) {
+		dev_dbg(&wdev->dev, "Unknown WMI event with payload %u", payload);
+		return;
+	}
+
+	/* AI key quirk */
+	if (entry->keycode == KEY_ASSISTANT) {
+		value = !(payload & AI_KEY_VALUE_MASK);
+		autorelease = false;
+	}
+
+	sparse_keymap_report_entry(data->input_dev, entry, value, autorelease);
+}
+
+static const struct wmi_device_id redmi_wmi_id_table[] = {
+	{ .guid_string = WMI_REDMIBOOK_KEYBOARD_EVENT_GUID },
+	{ }
+};
+
+static struct wmi_driver redmi_wmi_driver = {
+	.driver = {
+		.name = "redmi-wmi",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS
+	},
+	.id_table = redmi_wmi_id_table,
+	.probe = redmi_wmi_probe,
+	.notify = redmi_wmi_notify,
+	.no_singleton = true,
+};
+module_wmi_driver(redmi_wmi_driver);
+
+MODULE_DEVICE_TABLE(wmi, redmi_wmi_id_table);
+MODULE_AUTHOR("Gladyshev Ilya <foxido@foxido.dev>");
+MODULE_DESCRIPTION("Redmibook WMI driver");
+MODULE_LICENSE("GPL");
-- 
2.50.0

Re: [PATCH v2] platform/x86: Add WMI driver for Redmibook keyboard.

[Armin Wolf]

Am 29.07.25 um 21:05 schrieb Gladyshev Ilya:

> This driver implements support for various Fn keys (like Cut) and Xiaomi
> specific AI button.
>
> Signed-off-by: Gladyshev Ilya <foxido@foxido.dev>
> ---
>
> Changes from v1:
> - Use sparse-keymap instead of manual matching
> - Fix GUID case so it actually autoloads
> - Other fixes from v1 review
>
> Link to v1: https://lore.kernel.org/platform-driver-x86/20250727223516.29244-1-foxido@foxido.dev/
>
> ---
>   MAINTAINERS                      |   6 ++
>   drivers/platform/x86/Kconfig     |  11 +++
>   drivers/platform/x86/Makefile    |   1 +
>   drivers/platform/x86/redmi-wmi.c | 129 +++++++++++++++++++++++++++++++
>   4 files changed, 147 insertions(+)
>   create mode 100644 drivers/platform/x86/redmi-wmi.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c0b444e5fd5a..eb25fb10e751 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -20965,6 +20965,12 @@ S:	Maintained
>   T:	git https://github.com/pkshih/rtw.git
>   F:	drivers/net/wireless/realtek/rtw89/
>   
> +REDMIBOOK WMI DRIVERS
> +M:	Gladyshev Ilya <foxido@foxido.dev>
> +L:	platform-driver-x86@vger.kernel.org
> +S:	Maintained
> +F:	drivers/platform/x86/redmi-wmi.c
> +
>   REDPINE WIRELESS DRIVER
>   L:	linux-wireless@vger.kernel.org
>   S:	Orphan
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index e5cbd58a99f3..3c570cb398d3 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -109,6 +109,17 @@ config XIAOMI_WMI
>   	  To compile this driver as a module, choose M here: the module will
>   	  be called xiaomi-wmi.
>   
> +config REDMI_WMI
> +	tristate "Redmibook WMI key driver"
> +	depends on ACPI_WMI
> +	depends on INPUT

Please also select INPUT_SPARSEKMAP.

> +	help
> +	  Say Y here if you want support for WMI-based hotkey events on
> +	  Xiaomi Redmibook devices.
> +
> +	  To compile this driver as a module, choose M here: the module will
> +	  be called redmi-wmi.
> +
>   config GIGABYTE_WMI
>   	tristate "Gigabyte WMI temperature driver"
>   	depends on ACPI_WMI
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index bea87a85ae75..406dd0807ba7 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -13,6 +13,7 @@ obj-$(CONFIG_HUAWEI_WMI)		+= huawei-wmi.o
>   obj-$(CONFIG_MXM_WMI)			+= mxm-wmi.o
>   obj-$(CONFIG_NVIDIA_WMI_EC_BACKLIGHT)	+= nvidia-wmi-ec-backlight.o
>   obj-$(CONFIG_XIAOMI_WMI)		+= xiaomi-wmi.o
> +obj-$(CONFIG_REDMI_WMI)			+= redmi-wmi.o
>   obj-$(CONFIG_GIGABYTE_WMI)		+= gigabyte-wmi.o
>   
>   # Acer
> diff --git a/drivers/platform/x86/redmi-wmi.c b/drivers/platform/x86/redmi-wmi.c
> new file mode 100644
> index 000000000000..732688fb94e0
> --- /dev/null
> +++ b/drivers/platform/x86/redmi-wmi.c
> @@ -0,0 +1,129 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* WMI driver for Xiaomi Redmibooks */
> +
> +#include <linux/acpi.h>
> +#include <linux/device.h>
> +#include <linux/input.h>
> +#include <linux/input/sparse-keymap.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/unaligned.h>
> +#include <linux/wmi.h>
> +
> +#include <uapi/linux/input-event-codes.h>
> +
> +#define WMI_REDMIBOOK_KEYBOARD_EVENT_GUID "46C93E13-EE9B-4262-8488-563BCA757FEF"
> +
> +#define AI_KEY_VALUE_MASK 0x00000100
> +
> +static const struct key_entry redmi_wmi_keymap[] = {
> +	{KE_KEY, 0x00000201,	{KEY_SELECTIVE_SCREENSHOT}},
> +	{KE_KEY, 0x00000301,	{KEY_ALL_APPLICATIONS}},
> +	{KE_KEY, 0x00001b01,	{KEY_SETUP}},
> +
> +	/* AI button has code for each position */
> +	{KE_KEY, 0x00011801,	{KEY_ASSISTANT}},
> +	{KE_KEY, 0x00011901,	{KEY_ASSISTANT}},
> +
> +	/* Keyboard backlight */
> +	{KE_IGNORE, 0x00000501, {}},
> +	{KE_IGNORE, 0x00800501, {}},
> +	{KE_IGNORE, 0x00050501, {}},
> +	{KE_IGNORE, 0x000a0501, {}},
> +
> +	{KE_END}
> +};
> +
> +struct redmi_wmi {
> +	struct input_dev *input_dev;
> +	/* Protects the key event sequence */
> +	struct mutex key_lock;
> +};
> +
> +static int redmi_wmi_probe(struct wmi_device *wdev, const void *context)
> +{
> +	struct redmi_wmi *data;
> +	int err;
> +
> +	/* Init dev */
> +	data = devm_kzalloc(&wdev->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	dev_set_drvdata(&wdev->dev, data);
> +
> +	err = devm_mutex_init(&wdev->dev, &data->key_lock);
> +	if (err)
> +		return err;
> +
> +	/* Setup input device */
> +	data->input_dev = devm_input_allocate_device(&wdev->dev);
> +	if (!data->input_dev)
> +		return -ENOMEM;
> +	data->input_dev->name = "Redmibook WMI keys";
> +	data->input_dev->phys = "wmi/input0";
> +
> +	err = sparse_keymap_setup(data->input_dev, redmi_wmi_keymap, NULL);
> +	if (err)
> +		return err;
> +
> +	return input_register_device(data->input_dev);
> +}
> +
> +static void redmi_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
> +{
> +	struct redmi_wmi *data = dev_get_drvdata(&wdev->dev);
> +	int value = 1;
> +	bool autorelease = true;

Please order the variable declarations using reverse xmas tree order.

> +
> +	if (obj->type != ACPI_TYPE_BUFFER) {
> +		dev_err(&wdev->dev, "Bad response type %u\n", obj->type);
> +		return;
> +	}
> +
> +	if (obj->buffer.length != 32) {

Please also accept oversized buffers.

> +		dev_err(&wdev->dev, "Invalid buffer length %u\n", obj->buffer.length);
> +		return;
> +	}
> +
> +	/* For linearizability */
> +	guard(mutex)(&data->key_lock);
> +
> +	u32 payload = get_unaligned_le32(obj->buffer.pointer);
> +	struct key_entry *entry = sparse_keymap_entry_from_scancode(data->input_dev, payload);
> +
> +	if (!entry) {
> +		dev_dbg(&wdev->dev, "Unknown WMI event with payload %u", payload);
> +		return;
> +	}
> +
> +	/* AI key quirk */
> +	if (entry->keycode == KEY_ASSISTANT) {
> +		value = !(payload & AI_KEY_VALUE_MASK);

I would rather check the payload for 0x00011901 here.

Thanks,
Armin Wolf

> +		autorelease = false;
> +	}
> +
> +	sparse_keymap_report_entry(data->input_dev, entry, value, autorelease);
> +}
> +
> +static const struct wmi_device_id redmi_wmi_id_table[] = {
> +	{ .guid_string = WMI_REDMIBOOK_KEYBOARD_EVENT_GUID },
> +	{ }
> +};
> +
> +static struct wmi_driver redmi_wmi_driver = {
> +	.driver = {
> +		.name = "redmi-wmi",
> +		.probe_type = PROBE_PREFER_ASYNCHRONOUS
> +	},
> +	.id_table = redmi_wmi_id_table,
> +	.probe = redmi_wmi_probe,
> +	.notify = redmi_wmi_notify,
> +	.no_singleton = true,
> +};
> +module_wmi_driver(redmi_wmi_driver);
> +
> +MODULE_DEVICE_TABLE(wmi, redmi_wmi_id_table);
> +MODULE_AUTHOR("Gladyshev Ilya <foxido@foxido.dev>");
> +MODULE_DESCRIPTION("Redmibook WMI driver");
> +MODULE_LICENSE("GPL");

Re: [PATCH v2] platform/x86: Add WMI driver for Redmibook keyboard.

[Gladyshev Ilya]

Thx for review

On 7/30/25 19:33, Armin Wolf wrote:
>> +
>> +    if (obj->type != ACPI_TYPE_BUFFER) {
>> +        dev_err(&wdev->dev, "Bad response type %u\n", obj->type);
>> +        return;
>> +    }
>> +
>> +    if (obj->buffer.length != 32) {
> 
> Please also accept oversized buffers.
>
Sorry if this is a stupid question, but isn't any size other than 32 a 
sign of a firmware bug?

>> +
>> +    /* AI key quirk */
>> +    if (entry->keycode == KEY_ASSISTANT) {
>> +        value = !(payload & AI_KEY_VALUE_MASK);
> 
> I would rather check the payload for 0x00011901 here.
Personally I prefer to think about it as "some value encoded in payload" 
rather than "is it AI button release payload?", because in the latter 
case alternatives are more unclear. It's just a preference, btw, would 
fix if you insist.

--
Gladyshev Ilya

Re: [PATCH v2] platform/x86: Add WMI driver for Redmibook keyboard.

[Armin Wolf]

Am 30.07.25 um 19:37 schrieb Gladyshev Ilya:

> Thx for review
>
> On 7/30/25 19:33, Armin Wolf wrote:
>>> +
>>> +    if (obj->type != ACPI_TYPE_BUFFER) {
>>> +        dev_err(&wdev->dev, "Bad response type %u\n", obj->type);
>>> +        return;
>>> +    }
>>> +
>>> +    if (obj->buffer.length != 32) {
>>
>> Please also accept oversized buffers.
>>
> Sorry if this is a stupid question, but isn't any size other than 32 a 
> sign of a firmware bug?
>
Theoretically yes, practically no because the Windows WMI-ACPI driver does accept oversized buffers :(.

In order to support ACPI implementations that rely on the Windows behavior your driver should also
accept oversized buffers.

>>> +
>>> +    /* AI key quirk */
>>> +    if (entry->keycode == KEY_ASSISTANT) {
>>> +        value = !(payload & AI_KEY_VALUE_MASK);
>>
>> I would rather check the payload for 0x00011901 here.
> Personally I prefer to think about it as "some value encoded in 
> payload" rather than "is it AI button release payload?", because in 
> the latter case alternatives are more unclear. It's just a preference, 
> btw, would fix if you insist.
>
Alright, in this case you can ignore my comment.

Thanks,
Armin Wolf

> -- 
> Gladyshev Ilya
>

Re: [PATCH v2] platform/x86: Add WMI driver for Redmibook keyboard.

[Dmitry Torokhov]

On Tue, Jul 29, 2025 at 10:05:21PM +0300, Gladyshev Ilya wrote:
> +static void redmi_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
> +{
> +	struct redmi_wmi *data = dev_get_drvdata(&wdev->dev);
> +	int value = 1;
> +	bool autorelease = true;
> +
> +	if (obj->type != ACPI_TYPE_BUFFER) {
> +		dev_err(&wdev->dev, "Bad response type %u\n", obj->type);
> +		return;
> +	}
> +
> +	if (obj->buffer.length != 32) {
> +		dev_err(&wdev->dev, "Invalid buffer length %u\n", obj->buffer.length);
> +		return;
> +	}
> +
> +	/* For linearizability */
> +	guard(mutex)(&data->key_lock);

What is the exact purpose of this mutex? What does it protect? 

> +
> +	u32 payload = get_unaligned_le32(obj->buffer.pointer);
> +	struct key_entry *entry = sparse_keymap_entry_from_scancode(data->input_dev, payload);
> +
> +	if (!entry) {
> +		dev_dbg(&wdev->dev, "Unknown WMI event with payload %u", payload);
> +		return;
> +	}
> +
> +	/* AI key quirk */
> +	if (entry->keycode == KEY_ASSISTANT) {
> +		value = !(payload & AI_KEY_VALUE_MASK);
> +		autorelease = false;
> +	}
> +
> +	sparse_keymap_report_entry(data->input_dev, entry, value, autorelease);
> +}


Thanks.

-- 
Dmitry

Re: [PATCH v2] platform/x86: Add WMI driver for Redmibook keyboard.

[foxidokun]

> > +	/* For linearizability */
> > +	guard(mutex)(&data->key_lock);
>
> What is the exact purpose of this mutex? What does it protect? 

It protects key sequence, so there wouldn't be race between two press & release combinations resuulting into press - press - release - release order.

--
Gladyshev Ilya