linux-kernel - Re: [PATCH] ACPI / button: add support for tablet mode switch

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Message-ID: <CABicQ-XJaYGiDVKgefwN-6ckcwepUAvtpjJhwQN3cw389a+12w@mail.gmail.com>
Date:   Wed, 31 Aug 2016 16:52:19 +0800
From:   Wei-Ning Huang <wnhuang@...gle.com>
To:     Zhang Rui <rui.zhang@...el.com>
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI / button: add support for tablet mode switch

On Wed, Aug 31, 2016 at 4:01 PM, Zhang Rui <rui.zhang@...el.com> wrote:
> On 三, 2016-08-31 at 15:33 +0800, Wei-Ning Huang wrote:
>> From: Wei-Ning Huang <wnhuang@...omium.org>
>>
>> ACPI PNP device HID 'PNP0C60' is a device that indicates tablet mode
>> status. Add support for mapping this device to the SW_TABLET_MODE
>> input
>> event.
>>
>> Signed-off-by: Wei-Ning Huang <wnhuang@...omium.org>
>> ---
>>  drivers/acpi/button.c | 36 ++++++++++++++++++++++++++++++++++++
>>  1 file changed, 36 insertions(+)
>>
>> diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
>> index 148f4e5..50e9de6 100644
>> --- a/drivers/acpi/button.c
>> +++ b/drivers/acpi/button.c
>> @@ -53,6 +53,11 @@
>>  #define ACPI_BUTTON_DEVICE_NAME_LID  "Lid Switch"
>>  #define ACPI_BUTTON_TYPE_LID         0x05
>>
>> +#define ACPI_BUTTON_SUBCLASS_TABLET  "tablet"
>> +#define ACPI_BUTTON_HID_TABLET               "PNP0C60"
>> +#define ACPI_BUTTON_DEVICE_NAME_TABLET       "Tablet Mode Switch"
>> +#define ACPI_BUTTON_TYPE_TABLET              0x07
>> +
>>  #define ACPI_BUTTON_LID_INIT_IGNORE  0x00
>>  #define ACPI_BUTTON_LID_INIT_OPEN    0x01
>>  #define ACPI_BUTTON_LID_INIT_METHOD  0x02
>> @@ -70,6 +75,7 @@ static const struct acpi_device_id
>> button_device_ids[] = {
>>       {ACPI_BUTTON_HID_SLEEPF, 0},
>>       {ACPI_BUTTON_HID_POWER,  0},
>>       {ACPI_BUTTON_HID_POWERF, 0},
>> +     {ACPI_BUTTON_HID_TABLET, 0},
>>       {"", 0},
>>  };
>>  MODULE_DEVICE_TABLE(acpi, button_device_ids);
>> @@ -305,6 +311,23 @@ static void acpi_lid_initialize_state(struct
>> acpi_device *device)
>>       }
>>  }
>>
>> +static int acpi_tablet_send_state(struct acpi_device *device)
>> +{
>> +     struct acpi_button *button = acpi_driver_data(device);
>> +     unsigned long long state;
>> +     acpi_status status;
>> +
>> +     status = acpi_evaluate_integer(device->handle, "_TBL", NULL,
>> &state);
>
> Control methods with prefix "_" suggests this is an ACPI predefined
> control method, but I can not find it in ACPI spec 6.1.
> Can you illustrate me where I can find the definition of _TBL?

Sorry, I'm not very familiar with ACPI's control method.
'_TBL' is not a predefined ACPI control method according to the ACPI 6.1 spec.
Maybe I should change it to '_LID'? As a tablet switch is sort of a
'inverted' lid switch.

Wei-Ning
>
> thanks,
> rui
>> +     if (ACPI_FAILURE(status))
>> +             return -ENODEV;
>> +
>> +     /* input layer checks if event is redundant */
>> +     input_report_switch(button->input, SW_TABLET_MODE, state);
>> +     input_sync(button->input);
>> +
>> +     return 0;
>> +}
>> +
>>  static void acpi_button_notify(struct acpi_device *device, u32
>> event)
>>  {
>>       struct acpi_button *button = acpi_driver_data(device);
>> @@ -318,6 +341,8 @@ static void acpi_button_notify(struct acpi_device
>> *device, u32 event)
>>               input = button->input;
>>               if (button->type == ACPI_BUTTON_TYPE_LID) {
>>                       acpi_lid_update_state(device);
>> +             } else if (button->type == ACPI_BUTTON_TYPE_TABLET)
>> {
>> +                     acpi_tablet_send_state(device);
>>               } else {
>>                       int keycode;
>>
>> @@ -407,6 +432,11 @@ static int acpi_button_add(struct acpi_device
>> *device)
>>               strcpy(name, ACPI_BUTTON_DEVICE_NAME_LID);
>>               sprintf(class, "%s/%s",
>>                       ACPI_BUTTON_CLASS,
>> ACPI_BUTTON_SUBCLASS_LID);
>> +     } else if (!strcmp(hid, ACPI_BUTTON_HID_TABLET)) {
>> +             button->type = ACPI_BUTTON_TYPE_TABLET;
>> +             strcpy(name, ACPI_BUTTON_DEVICE_NAME_TABLET);
>> +             sprintf(class, "%s/%s",
>> +                     ACPI_BUTTON_CLASS,
>> ACPI_BUTTON_SUBCLASS_TABLET);
>>       } else {
>>               printk(KERN_ERR PREFIX "Unsupported hid [%s]\n",
>> hid);
>>               error = -ENODEV;
>> @@ -437,6 +467,10 @@ static int acpi_button_add(struct acpi_device
>> *device)
>>       case ACPI_BUTTON_TYPE_LID:
>>               input_set_capability(input, EV_SW, SW_LID);
>>               break;
>> +
>> +     case ACPI_BUTTON_TYPE_TABLET:
>> +             input_set_capability(input, EV_SW, SW_TABLET_MODE);
>> +             break;
>>       }
>>
>>       error = input_register_device(input);
>> @@ -450,6 +484,8 @@ static int acpi_button_add(struct acpi_device
>> *device)
>>                */
>>               lid_device = device;
>>       }
>> +     if (button->type == ACPI_BUTTON_TYPE_TABLET)
>> +             acpi_tablet_send_state(device);
>>
>>       printk(KERN_INFO PREFIX "%s [%s]\n", name,
>> acpi_device_bid(device));
>>       return 0;



-- 
Wei-Ning Huang, 黃偉寧 | Software Engineer, Google Inc., Taiwan |
wnhuang@...gle.com | Cell: +886 910-380678