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[PATCH v2] Add driver to force WMI Thunderbolt controller power status

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  [PATCH v2] Add driver to force WMI Thunderbolt controller power status Mario Limonciello <mario.limonciello@dell.com> - 2017-09-07 20:50 +0200
    Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power  status "Bernat, Yehezkel" <yehezkel.bernat@intel.com> - 2017-09-07 21:20 +0200
      RE: [PATCH v2] Add driver to force WMI Thunderbolt controller power  status <Mario.Limonciello@dell.com> - 2017-09-07 22:20 +0200
        Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power  status Darren Hart <dvhart@infradead.org> - 2017-09-08 02:10 +0200
    Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power  status Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-09-08 10:20 +0200
      RE: [PATCH v2] Add driver to force WMI Thunderbolt controller power  status <Mario.Limonciello@dell.com> - 2017-09-08 17:20 +0200
        Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power  status Darren Hart <dvhart@infradead.org> - 2017-09-09 06:20 +0200
          Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power  status Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-09-09 09:10 +0200

#1728386 — [PATCH v2] Add driver to force WMI Thunderbolt controller power status

Current implementations of Intel Thunderbolt controllers will go
into a low power mode when not in use.

Many machines containing these controllers also have a GPIO wired up
that can force the controller awake.  This is offered via a ACPI-WMI
interface intended to be manipulated by a userspace utility.

This mechanism is provided by Intel to OEMs to include in BIOS.
It uses an industry wide GUID that is populated in a separate _WDG
entry with no binary MOF.

This interface allows software such as fwupd to wake up thunderbolt
controllers to query the firmware version or flash new firmware.

Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
---
changes from v1 to v2:
 * Add ABI documentation
 * Update thunderbolt.rst
 * Remove unnecessary cast
 * Remove unneeded whitespace
 * Adjust references of "Intel Wmi thunderbolt" -> 
   "Intel WMI thunderbolt force power"

 .../testing/sysfs-platform-intel-wmi-thunderbolt   | 11 +++
 Documentation/admin-guide/thunderbolt.rst          | 15 ++++
 MAINTAINERS                                        |  5 ++
 drivers/platform/x86/Kconfig                       | 13 +++
 drivers/platform/x86/Makefile                      |  1 +
 drivers/platform/x86/intel-wmi-thunderbolt.c       | 96 ++++++++++++++++++++++
 6 files changed, 141 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-platform-intel-wmi-thunderbolt
 create mode 100644 drivers/platform/x86/intel-wmi-thunderbolt.c

diff --git a/Documentation/ABI/testing/sysfs-platform-intel-wmi-thunderbolt b/Documentation/ABI/testing/sysfs-platform-intel-wmi-thunderbolt
new file mode 100644
index 0000000..7b8e61a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-intel-wmi-thunderbolt
@@ -0,0 +1,11 @@
+What:		/sys/devices/platform/<platform>/force_power
+Date:		September 2017
+KernelVersion:	4.14
+Contact:	"Mario LimonciellO" <mario.limonciello@dell.com>
+Description:
+		Modify the platform force power state, influencing
+		Thunderbolt controllers to turn on or off when no
+		devices are connected (write-only)
+		There are two available states:
+		    * 0 -> Force power disabled
+		    * 1 -> Force power enabled
diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst
index 6a4cd1f..dadcd66 100644
--- a/Documentation/admin-guide/thunderbolt.rst
+++ b/Documentation/admin-guide/thunderbolt.rst
@@ -197,3 +197,18 @@ information is missing.
 
 To recover from this mode, one needs to flash a valid NVM image to the
 host host controller in the same way it is done in the previous chapter.
+
+Forcing power
+-------------
+Many OEMs include a method that can be used to force the power of a
+thunderbolt controller to an "On" state even if nothing is connected.
+If supported by your machine this will be exposed by the WMI bus with
+a sysfs attribute called "force_power".
+
+For example the intel-wmi-thunderbolt driver exposes this attribute in:
+  /sys/devices/platform/PNP0C14:00/wmi_bus/wmi_bus-PNP0C14:00/86CCFD48-205E-4A77-9C48-2021CBEDE341/force_power
+
+  To force the power to on, write 1 to this attribute file.
+  To disable force power, write 0 to this attribute file.
+
+Note: it's currently not possible to query the force power state of a platform.
diff --git a/MAINTAINERS b/MAINTAINERS
index 1c3feff..9a6b73e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3949,6 +3949,11 @@ M:	Pali Rohár <pali.rohar@gmail.com>
 S:	Maintained
 F:	drivers/platform/x86/dell-wmi.c
 
+INTEL WMI THUNDERBOLT FORCE POWER DRIVER
+M:	Mario Limonciello <mario.limonciello@dell.com>
+S:	Maintained
+F:	drivers/platform/x86/intel-wmi-thunderbolt.c
+
 DELTA ST MEDIA DRIVER
 M:	Hugues Fruchet <hugues.fruchet@st.com>
 L:	linux-media@vger.kernel.org
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 80b8795..f401ae4 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -658,6 +658,19 @@ config WMI_BMOF
 	  To compile this driver as a module, choose M here: the module will
 	  be called wmi-bmof.
 
+config INTEL_WMI_THUNDERBOLT
+	tristate "Intel WMI thunderbolt force power driver"
+	depends on ACPI_WMI
+	default ACPI_WMI
+	---help---
+	  Say Y here if you want to be able to use the WMI interface on select
+	  systems to force the power control of Intel Thunderbolt controllers.
+	  This is useful for updating the firmware when devices are not plugged
+	  into the controller.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called intel-wmi-thunderbolt.
+
 config MSI_WMI
 	tristate "MSI WMI extras"
 	depends on ACPI_WMI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 91cec17..2b315d0 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_PEAQ_WMI)		+= peaq-wmi.o
 obj-$(CONFIG_SURFACE3_WMI)	+= surface3-wmi.o
 obj-$(CONFIG_TOPSTAR_LAPTOP)	+= topstar-laptop.o
 obj-$(CONFIG_WMI_BMOF)		+= wmi-bmof.o
+obj-$(CONFIG_INTEL_WMI_THUNDERBOLT)	+= intel-wmi-thunderbolt.o
 
 # toshiba_acpi must link after wmi to ensure that wmi devices are found
 # before toshiba_acpi initializes
diff --git a/drivers/platform/x86/intel-wmi-thunderbolt.c b/drivers/platform/x86/intel-wmi-thunderbolt.c
new file mode 100644
index 0000000..e8c98dc
--- /dev/null
+++ b/drivers/platform/x86/intel-wmi-thunderbolt.c
@@ -0,0 +1,96 @@
+/*
+ * WMI Thunderbolt driver
+ *
+ * Copyright (C) 2017 Dell Inc. All Rights Reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+#include <linux/wmi.h>
+
+#define INTEL_WMI_THUNDERBOLT_GUID "86CCFD48-205E-4A77-9C48-2021CBEDE341"
+
+static ssize_t force_power_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t count)
+{
+	struct acpi_buffer input;
+	acpi_status status;
+	u8 mode;
+
+	input.length = sizeof(u8);
+	input.pointer = &mode;
+	mode = hex_to_bin(buf[0]);
+	if (mode == 0 || mode == 1) {
+		status = wmi_evaluate_method(INTEL_WMI_THUNDERBOLT_GUID, 0, 1,
+					     &input, NULL);
+		if (ACPI_FAILURE(status)) {
+			pr_err("intel-wmi-thunderbolt: failed setting %s\n",
+			       buf);
+			return -ENODEV;
+		}
+	} else {
+		pr_err("intel-wmi-thunderbolt: unsupported mode: %d", mode);
+	}
+	return count;
+}
+
+static DEVICE_ATTR_WO(force_power);
+
+static struct attribute *tbt_attrs[] = {
+	&dev_attr_force_power.attr,
+	NULL
+};
+
+static const struct attribute_group tbt_attribute_group = {
+	.attrs = tbt_attrs,
+};
+
+static int intel_wmi_thunderbolt_probe(struct wmi_device *wdev)
+{
+	return sysfs_create_group(&wdev->dev.kobj, &tbt_attribute_group);
+}
+
+static int intel_wmi_thunderbolt_remove(struct wmi_device *wdev)
+{
+	sysfs_remove_group(&wdev->dev.kobj, &tbt_attribute_group);
+	return 0;
+}
+
+static const struct wmi_device_id intel_wmi_thunderbolt_id_table[] = {
+	{ .guid_string = INTEL_WMI_THUNDERBOLT_GUID },
+	{ },
+};
+
+static struct wmi_driver intel_wmi_thunderbolt_driver = {
+	.driver = {
+		.name = "intel-wmi-thunderbolt",
+	},
+	.probe = intel_wmi_thunderbolt_probe,
+	.remove = intel_wmi_thunderbolt_remove,
+	.id_table = intel_wmi_thunderbolt_id_table,
+};
+
+module_wmi_driver(intel_wmi_thunderbolt_driver);
+
+MODULE_ALIAS("wmi:" INTEL_WMI_THUNDERBOLT_GUID);
+MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>");
+MODULE_DESCRIPTION("Intel WMI Thunderbolt force power driver");
+MODULE_LICENSE("GPL");
-- 
2.7.4

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#1728394 — Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power status

> +Contact:       "Mario LimonciellO" <mario.limonciello@dell.com>
                                   ^
Looks like a typo

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#1728409 — RE: [PATCH v2] Add driver to force WMI Thunderbolt controller power status

> -----Original Message-----
> From: Bernat, Yehezkel [mailto:yehezkel.bernat@intel.com]
> Sent: Thursday, September 7, 2017 2:15 PM
> To: dvhart@infradead.org; Limonciello, Mario <Mario_Limonciello@Dell.com>
> Cc: mika.westerberg@linux.intel.com; linux-kernel@vger.kernel.org; platform-
> driver-x86@vger.kernel.org; hughsient@gmail.com
> Subject: Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power
> status
> 
> 
> > +Contact:       "Mario LimonciellO" <mario.limonciello@dell.com>
>                                    ^
> Looks like a typo

Yep - fat fingered shift while adding the second " :)

If that's all that's left, hopefully Daren can just fix it when committing.

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#1728513 — Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power status

On Thu, Sep 07, 2017 at 08:09:28PM +0000, Mario.Limonciello@dell.com wrote:
> > -----Original Message-----
> > From: Bernat, Yehezkel [mailto:yehezkel.bernat@intel.com]
> > Sent: Thursday, September 7, 2017 2:15 PM
> > To: dvhart@infradead.org; Limonciello, Mario <Mario_Limonciello@Dell.com>
> > Cc: mika.westerberg@linux.intel.com; linux-kernel@vger.kernel.org; platform-
> > driver-x86@vger.kernel.org; hughsient@gmail.com
> > Subject: Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power
> > status
> > 
> > 
> > > +Contact:       "Mario LimonciellO" <mario.limonciello@dell.com>
> >                                    ^
> > Looks like a typo
> 
> Yep - fat fingered shift while adding the second " :)
> 
> If that's all that's left, hopefully Daren can just fix it when committing.

Yup. I'd like an Reviewed-by from Mika. Bernat, you two if you're happy with it.
Appreciate all the reviews.

-- 
Darren Hart
VMware Open Source Technology Center

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#1728675 — Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power status

On Thu, Sep 07, 2017 at 01:47:22PM -0500, Mario Limonciello wrote:

I have a small comment which you might want to consider.

> +static int intel_wmi_thunderbolt_probe(struct wmi_device *wdev)
> +{
> +	return sysfs_create_group(&wdev->dev.kobj, &tbt_attribute_group);
> +}
> +
> +static int intel_wmi_thunderbolt_remove(struct wmi_device *wdev)
> +{
> +	sysfs_remove_group(&wdev->dev.kobj, &tbt_attribute_group);
> +	return 0;
> +}

In order to notify userspace about this, what if you send KOBJ_CHANGE
for the wdev when you add/remove this attribute?

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#1729020 — RE: [PATCH v2] Add driver to force WMI Thunderbolt controller power status

> -----Original Message-----
> From: Mika Westerberg [mailto:mika.westerberg@linux.intel.com]
> Sent: Friday, September 8, 2017 3:07 AM
> To: Limonciello, Mario <Mario_Limonciello@Dell.com>
> Cc: dvhart@infradead.org; LKML <linux-kernel@vger.kernel.org>; platform-driver-
> x86@vger.kernel.org; Richard Hughes <hughsient@gmail.com>; Yehezkel Bernat
> <yehezkelshb@gmail.com>
> Subject: Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power
> status
> 
> On Thu, Sep 07, 2017 at 01:47:22PM -0500, Mario Limonciello wrote:
> 
> I have a small comment which you might want to consider.
> 
> > +static int intel_wmi_thunderbolt_probe(struct wmi_device *wdev)
> > +{
> > +	return sysfs_create_group(&wdev->dev.kobj, &tbt_attribute_group);
> > +}
> > +
> > +static int intel_wmi_thunderbolt_remove(struct wmi_device *wdev)
> > +{
> > +	sysfs_remove_group(&wdev->dev.kobj, &tbt_attribute_group);
> > +	return 0;
> > +}
> 
> In order to notify userspace about this, what if you send KOBJ_CHANGE
> for the wdev when you add/remove this attribute?

Sure, makes sense to me.   I'll send a follow up patch.

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#1729382 — Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power status

On Fri, Sep 08, 2017 at 03:15:10PM +0000, Mario.Limonciello@dell.com wrote:
> > -----Original Message-----
> > From: Mika Westerberg [mailto:mika.westerberg@linux.intel.com]
> > Sent: Friday, September 8, 2017 3:07 AM
> > To: Limonciello, Mario <Mario_Limonciello@Dell.com>
> > Cc: dvhart@infradead.org; LKML <linux-kernel@vger.kernel.org>; platform-driver-
> > x86@vger.kernel.org; Richard Hughes <hughsient@gmail.com>; Yehezkel Bernat
> > <yehezkelshb@gmail.com>
> > Subject: Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power
> > status
> > 
> > On Thu, Sep 07, 2017 at 01:47:22PM -0500, Mario Limonciello wrote:
> > 
> > I have a small comment which you might want to consider.
> > 
> > > +static int intel_wmi_thunderbolt_probe(struct wmi_device *wdev)
> > > +{
> > > +	return sysfs_create_group(&wdev->dev.kobj, &tbt_attribute_group);
> > > +}
> > > +
> > > +static int intel_wmi_thunderbolt_remove(struct wmi_device *wdev)
> > > +{
> > > +	sysfs_remove_group(&wdev->dev.kobj, &tbt_attribute_group);
> > > +	return 0;
> > > +}
> > 
> > In order to notify userspace about this, what if you send KOBJ_CHANGE
> > for the wdev when you add/remove this attribute?
> 
> Sure, makes sense to me.   I'll send a follow up patch.

Hrm, what am I missing.... the reason I recommended Mario add the attribute
group was so this would be automatically taken care of prior to the KOBJ_ADD
event, per the device documentation:

driver-model/device.txt

-- 
Darren Hart
VMware Open Source Technology Center

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#1729400 — Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power status

On Fri, Sep 08, 2017 at 09:14:52PM -0700, Darren Hart wrote:
> On Fri, Sep 08, 2017 at 03:15:10PM +0000, Mario.Limonciello@dell.com wrote:
> > > -----Original Message-----
> > > From: Mika Westerberg [mailto:mika.westerberg@linux.intel.com]
> > > Sent: Friday, September 8, 2017 3:07 AM
> > > To: Limonciello, Mario <Mario_Limonciello@Dell.com>
> > > Cc: dvhart@infradead.org; LKML <linux-kernel@vger.kernel.org>; platform-driver-
> > > x86@vger.kernel.org; Richard Hughes <hughsient@gmail.com>; Yehezkel Bernat
> > > <yehezkelshb@gmail.com>
> > > Subject: Re: [PATCH v2] Add driver to force WMI Thunderbolt controller power
> > > status
> > > 
> > > On Thu, Sep 07, 2017 at 01:47:22PM -0500, Mario Limonciello wrote:
> > > 
> > > I have a small comment which you might want to consider.
> > > 
> > > > +static int intel_wmi_thunderbolt_probe(struct wmi_device *wdev)
> > > > +{
> > > > +	return sysfs_create_group(&wdev->dev.kobj, &tbt_attribute_group);
> > > > +}
> > > > +
> > > > +static int intel_wmi_thunderbolt_remove(struct wmi_device *wdev)
> > > > +{
> > > > +	sysfs_remove_group(&wdev->dev.kobj, &tbt_attribute_group);
> > > > +	return 0;
> > > > +}
> > > 
> > > In order to notify userspace about this, what if you send KOBJ_CHANGE
> > > for the wdev when you add/remove this attribute?
> > 
> > Sure, makes sense to me.   I'll send a follow up patch.
> 
> Hrm, what am I missing.... the reason I recommended Mario add the attribute
> group was so this would be automatically taken care of prior to the KOBJ_ADD
> event, per the device documentation:
> 
> driver-model/device.txt

At this point the KOBJ_ADD event has already been send to the userspace
when the device was added to the system.

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