Re: [PATCH] platform/x86: wmi: add Positivo WMI key driver

[Armin Wolf <W_Armin@gmx.de>]

Am 28.06.23 um 23:04 schrieb Armin Wolf:

> Am 28.06.23 um 23:40 schrieb Edson Juliano Drosdeck:
>
>> Some function keys on the built in keyboard on Positivo's notebooks does
>> not produce any key events when pressed in combination with the function
>> key. Some of these keys do report that they are being pressed via WMI
>> events.
>>
>> This driver reports key events for Fn+F10,Fn+F11  and a custom key to
>> launch a custom program.
>>
>> Other WMI events that are reported by the hardware but not utilized by
>> this driver are Caps Lock(which already work).
>>
>> Signed-off-by: Edson Juliano Drosdeck <edson.drosdeck@gmail.com>
>> ---
>>   drivers/platform/x86/Kconfig        |  11 +++
>>   drivers/platform/x86/Makefile       |   1 +
>>   drivers/platform/x86/positivo-wmi.c | 136 ++++++++++++++++++++++++++++
>>   3 files changed, 148 insertions(+)
>>   create mode 100644 drivers/platform/x86/positivo-wmi.c
>>
>> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
>> index 22052031c719..f3ad84479460 100644
>> --- a/drivers/platform/x86/Kconfig
>> +++ b/drivers/platform/x86/Kconfig
>> @@ -134,6 +134,17 @@ config YOGABOOK_WMI
>>         To compile this driver as a module, choose M here: the module
>> will
>>         be called lenovo-yogabook-wmi.
>>
>> +config POSITIVO_WMI
>> +    tristate "Positivo WMI key driver"
>> +    depends on ACPI_WMI
>> +    depends on INPUT
>> +    select INPUT_SPARSEKMAP
>> +    help
>> +      This driver provides support for Positvo WMI hotkeys.
>> +
>> +      To compile this driver as a module, choose M here: the module
>> +      will be called positivo-wmi.
>> +
>>   config ACERHDF
>>       tristate "Acer Aspire One temperature and fan driver"
>>       depends on ACPI && THERMAL
>> diff --git a/drivers/platform/x86/Makefile
>> b/drivers/platform/x86/Makefile
>> index 2cafe51ec4d8..5458bb9a56d3 100644
>> --- a/drivers/platform/x86/Makefile
>> +++ b/drivers/platform/x86/Makefile
>> @@ -15,6 +15,7 @@ obj-$(CONFIG_NVIDIA_WMI_EC_BACKLIGHT)    +=
>> nvidia-wmi-ec-backlight.o
>>   obj-$(CONFIG_XIAOMI_WMI)        += xiaomi-wmi.o
>>   obj-$(CONFIG_GIGABYTE_WMI)        += gigabyte-wmi.o
>>   obj-$(CONFIG_YOGABOOK_WMI)        += lenovo-yogabook-wmi.o
>> +obj-$(CONFIG_POSITIVO_WMI)        += positivo-wmi.o
>>
>>   # Acer
>>   obj-$(CONFIG_ACERHDF)        += acerhdf.o
>> diff --git a/drivers/platform/x86/positivo-wmi.c
>> b/drivers/platform/x86/positivo-wmi.c
>> new file mode 100644
>> index 000000000000..5fbb4cf42154
>> --- /dev/null
>> +++ b/drivers/platform/x86/positivo-wmi.c
>> @@ -0,0 +1,136 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +
>> +/* WMI driver for Positivo Laptops
>> + *
>> + * Copyright (C) 2023 Edson Juliano Drosdeck <edson.drosdeck@gmail.com>
>> + *
>> + * */
>> +
>> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/acpi.h>
>> +#include <linux/input.h>
>> +#include <linux/input/sparse-keymap.h>
>> +#include <linux/dmi.h>
>> +#include <linux/module.h>
>> +
>> +MODULE_AUTHOR("Edson Juliano Drosdeck");
>> +MODULE_DESCRIPTION("Positivo WMI Hotkey Driver");
>> +MODULE_LICENSE("GPL");
>> +
>> +#define POSITIVO_WMI_EVENT_GUID "ABBC0F72-8EA1-11D1-00A0-C90629100000"
>> +
>> +MODULE_ALIAS("wmi:"POSITIVO_WMI_EVENT_GUID);
>> +
>> +static const struct key_entry positivo_wmi_keymap[] = {
>> +    { KE_KEY, 0x1c, { KEY_PROG1} },
>> +    { KE_KEY, 0x36, { KEY_WLAN } },
>> +    { KE_KEY, 0x37, { KEY_BLUETOOTH } },
>> +    { KE_END, 0},
>> +};
>> +
>> +static struct input_dev *positivo_wmi_input_dev;
>> +
>> +static void positivo_wmi_notify(u32 value, void *context)
>> +{
>> +    struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
>> +    union acpi_object *obj;
>> +    int eventcode;
>> +    acpi_status status;
>> +
>> +    status = wmi_get_event_data(value, &response);
>> +    if (status != AE_OK) {
>> +        pr_err("bad event status 0x%x\n", status);
>> +        return;
>> +    }
>> +
>> +    obj = (union acpi_object *)response.pointer;
>> +    if (obj && obj->type == ACPI_TYPE_INTEGER) {
>> +        eventcode = obj->integer.value;
>> +
>> +        if (!sparse_keymap_report_event(positivo_wmi_input_dev,
>> +                        eventcode, 1, true))
>> +            pr_err("Unknown key %x pressed\n", eventcode);
>> +    }
>> +
>> +    kfree(response.pointer);
>> +}
>> +
>> +static int positivo_wmi_input_setup(void)
>> +{
>> +
>> +    int err;
>> +
>> +    positivo_wmi_input_dev = input_allocate_device();
>> +    if (!positivo_wmi_input_dev)
>> +        return -ENOMEM;
>> +
>> +    positivo_wmi_input_dev->name = "Positivo laptop WMI hotkeys";
>> +    positivo_wmi_input_dev->phys = "wmi/input0";
>> +    positivo_wmi_input_dev->id.bustype = BUS_HOST;
>> +
>> +    err = sparse_keymap_setup(positivo_wmi_input_dev,
>> +                  positivo_wmi_keymap, NULL);
>> +    if (err)
>> +        goto err_free_dev;
>> +
>> +    err = input_register_device(positivo_wmi_input_dev);
>> +
>> +    if (err){
>> +        pr_info("Unable to register input device\n");
>> +        goto err_free_dev;
>> +    }
>> +
>> +    return 0;
>> +
>> +err_free_dev:
>> +    input_free_device(positivo_wmi_input_dev);
>> +    return err;
>> +}
>> +
>> +static const struct dmi_system_id positivo_wmi_dmi_table[]
>> __initconst = {
>> +    {
>> +        .ident = "Positivo laptop",
>> +        .matches = {
>> +            DMI_MATCH(DMI_SYS_VENDOR, "Positivo Tecnologia SA"),
>> +        },
>> +    },
>> +    {}
>> +};
>
> Hello,
>
> it would be better if the driver matches on the WMI GUID. More on this
> below.

I just found out that the WMI GUID used by the driver (ABBC0F72-8EA1-11D1-00A0-C90629100000),
which is supposed to be unique, is actually also used by the eeepc-wmi driver.

This _should_ normally not happen, but it seems that Positivio reused a WMI GUID found inside
the Microsoft ACPI WMI driver samples (line 227), which can be found under:
https://github.com/microsoft/Windows-driver-samples/blob/main/wmi/wmiacpi/acpimof.mof

Could you share the output of "acpidump"? I would be very interested to find out why this
WMI GUID is not unique.

Armin Wolf

>
>> +
>> +static int __init positivo_wmi_init(void)
>> +{
>> +    int err;
>> +
>> +    if (!wmi_has_guid(POSITIVO_WMI_EVENT_GUID) ||
>> +        !dmi_check_system(positivo_wmi_dmi_table))
>> +        return -ENODEV;
>> +
>> +    err = positivo_wmi_input_setup();
>> +    if (err)
>> +        return err;
>> +
>> +    err = wmi_install_notify_handler(POSITIVO_WMI_EVENT_GUID,
>> +                    positivo_wmi_notify, NULL);
>
> Please use the newer bus-based WMI interface. The legacy GUID-based
> interface is
> deprecated an has several issues. I recommend you to take a look at
> the xiaomi-wmi
> driver. It seems to do a very similar thing and uses the modern
> bus-based WMI interface.
> The only big difference is that your driver uses the acpi_object
> passed by the notify
> callback to determine the key code.
>
> You can find more documentation regarding the bus-based WMI interface
> under:
> https://www.kernel.org/doc/html/next/driver-api/wmi.html
>
> Thanks,
> Armin Wolf
>
>> +        if (ACPI_FAILURE(err)) {
>> +            pr_err("Unable to setup WMI notify handler\n");
>> +            goto err_free_input;
>> +        }
>> +
>> +    return 0;
>> +
>> +err_free_input:
>> +    input_unregister_device(positivo_wmi_input_dev);
>> +    return err;
>> +
>> +}
>> +
>> +static void __exit positivo_wmi_exit(void)
>> +{
>> +       wmi_remove_notify_handler(POSITIVO_WMI_EVENT_GUID);
>> +       input_free_device(positivo_wmi_input_dev);
>> +}
>> +
>> +module_init(positivo_wmi_init);
>> +module_exit(positivo_wmi_exit);