linux-kernel - RE: [PATCH v3] Support intel-vbtn based tablet mode switch

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Message-ID: <ac4ffb2b86ef450b90eec53f5a97bcbc@ausx13mpc120.AMER.DELL.COM>
Date:   Tue, 23 Jan 2018 14:51:49 +0000
From:   <Mario.Limonciello@...l.com>
To:     <notmart@...il.com>, <linux-kernel@...r.kernel.org>
CC:     <mjg59@...f.ucam.org>, <pali.rohar@...il.com>,
        <dvhart@...radead.org>, <andy@...radead.org>, <bhush94@...il.com>,
        <platform-driver-x86@...r.kernel.org>
Subject: RE: [PATCH v3] Support intel-vbtn based tablet mode switch

> -----Original Message-----
> From: platform-driver-x86-owner@...r.kernel.org [mailto:platform-driver-x86-
> owner@...r.kernel.org] On Behalf Of Marco Martin
> Sent: Tuesday, January 23, 2018 6:42 AM
> To: linux-kernel@...r.kernel.org
> Cc: mjg59@...f.ucam.org; pali.rohar@...il.com; dvhart@...radead.org;
> andy@...radead.org; bhush94@...il.com; platform-driver-x86@...r.kernel.org;
> Limonciello, Mario <Mario_Limonciello@...l.com>; Marco Martin
> <notmart@...il.com>; Limonciello, Mario <Mario_Limonciello@...l.com>
> Subject: [PATCH v3] Support intel-vbtn based tablet mode switch
> 
> Some laptops such as Dell Inspiron 7000 series have the
> tablet mode switch implemented in Intel ACPI,
> the events to enter and exit the tablet mode are 0xCC and 0xCD
> 
> CC: platform-driver-x86@...r.kernel.org
> CC: Matthew Garrett <mjg59@...f.ucam.org>
> CC: "Pali Rohár" <pali.rohar@...il.com>
> CC: Darren Hart <dvhart@...radead.org>
> CC: Mario Limonciello <mario_limonciello@...l.com>
> CC: Andy Shevchenko <andy@...radead.org>
> 
> Signed-off-by: Marco Martin <notmart@...il.com>
> ---
>  drivers/platform/x86/intel-vbtn.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/drivers/platform/x86/intel-vbtn.c b/drivers/platform/x86/intel-vbtn.c
> index 58c5ff3..64b4b34 100644
> --- a/drivers/platform/x86/intel-vbtn.c
> +++ b/drivers/platform/x86/intel-vbtn.c
> @@ -26,6 +26,9 @@
>  #include <linux/suspend.h>
>  #include <acpi/acpi_bus.h>
> 
> +/* When NOT in tablet mode, VBDS has the flag 0x40 */
> +#define TABLET_MODE_FLAG 0x40

Minor typographical error here, you mean VGBS output
not VDBS right?

VDBS may be implementation specific, you're explicitly
looking at VGBS.

> +
>  MODULE_LICENSE("GPL");
>  MODULE_AUTHOR("AceLan Kao");
> 
> @@ -42,6 +45,8 @@ static const struct key_entry intel_vbtn_keymap[] = {
>  	{ KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },		/* volume-up key
> release */
>  	{ KE_KEY, 0xC6, { KEY_VOLUMEDOWN } },		/* volume-down
> key press */
>  	{ KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },	/* volume-down key
> release */
> +	{ KE_SW,  0xCC, { .sw = { SW_TABLET_MODE, 1 } } }, /* Tablet mode in */
> +	{ KE_SW,  0xCD, { .sw = { SW_TABLET_MODE, 0 } } }, /* Tablet mode out */
>  	{ KE_END },
>  };
> 
> @@ -88,6 +93,7 @@ static void notify_handler(acpi_handle handle, u32 event,
> void *context)
> 
>  static int intel_vbtn_probe(struct platform_device *device)
>  {
> +	struct acpi_buffer vgbs_output = { ACPI_ALLOCATE_BUFFER, NULL };
>  	acpi_handle handle = ACPI_HANDLE(&device->dev);
>  	struct intel_vbtn_priv *priv;
>  	acpi_status status;
> @@ -110,6 +116,21 @@ static int intel_vbtn_probe(struct platform_device
> *device)
>  		return err;
>  	}
> 
> +	status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
> +	/* VGBS being present and returning something means
> +	 * we have a tablet mode switch
> +	 */
> +	if (ACPI_SUCCESS(status)) {
> +		union acpi_object *obj = vgbs_output.pointer;
> +
> +		if (obj && obj->type == ACPI_TYPE_INTEGER) {
> +			input_set_capability(priv->input_dev, EV_SW,
> SW_TABLET_MODE);
> +			input_report_switch(priv->input_dev,
> +
> 	SW_TABLET_MODE,
> +								!(obj-
> >integer.value & TABLET_MODE_FLAG));
> +		}
> +	}
> +
>  	status = acpi_install_notify_handler(handle,
>  					     ACPI_DEVICE_NOTIFY,
>  					     notify_handler,
> --
> 2.7.4