linux-surface/patches/4.19/0004-surface-buttons.patch

From 25c1108f70fde7cca28e5f851427108737443088 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sat, 27 Jul 2019 17:51:37 +0200
Subject: [PATCH 04/10] surface-buttons

---
 drivers/input/misc/Kconfig                |   6 +-
 drivers/input/misc/soc_button_array.c     | 114 +++++++++++++++++++---
 drivers/platform/x86/surfacepro3_button.c |  47 +++++++++
 3 files changed, 151 insertions(+), 16 deletions(-)

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index ca59a2be9bc5..ea69610370e8 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -781,10 +781,10 @@ config INPUT_IDEAPAD_SLIDEBAR
 
 config INPUT_SOC_BUTTON_ARRAY
 	tristate "Windows-compatible SoC Button Array"
-	depends on KEYBOARD_GPIO
+	depends on KEYBOARD_GPIO && ACPI
 	help
-	  Say Y here if you have a SoC-based tablet that originally
-	  runs Windows 8.
+	  Say Y here if you have a SoC-based tablet that originally runs
+	  Windows 8 or a Microsoft Surface Book 2, Pro 5, Laptop 1 or later.
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called soc_button_array.
diff --git a/drivers/input/misc/soc_button_array.c b/drivers/input/misc/soc_button_array.c
index 55cd6e0b409c..c564ea99f47d 100644
--- a/drivers/input/misc/soc_button_array.c
+++ b/drivers/input/misc/soc_button_array.c
@@ -29,6 +29,11 @@ struct soc_button_info {
 	bool wakeup;
 };
 
+struct soc_device_data {
+	const struct soc_button_info *button_info;
+	int (*check)(struct device *dev);
+};
+
 /*
  * Some of the buttons like volume up/down are auto repeat, while others
  * are not. To support both, we register two platform devices, and put
@@ -91,8 +96,20 @@ soc_button_device_create(struct platform_device *pdev,
 			continue;
 
 		gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
-		if (!gpio_is_valid(gpio))
+		if (!gpio_is_valid(gpio)) {
+			/*
+			 * Skip GPIO if not present. Note we deliberately
+			 * ignore -EPROBE_DEFER errors here. On some devices
+			 * Intel is using so called virtual GPIOs which are not
+			 * GPIOs at all but some way for AML code to check some
+			 * random status bits without need a custom opregion.
+			 * In some cases the resources table we parse points to
+			 * such a virtual GPIO, since these are not real GPIOs
+			 * we do not have a driver for these so they will never
+			 * show up, therefor we ignore -EPROBE_DEFER.
+			 */
 			continue;
+		}
 
 		gpio_keys[n_buttons].type = info->event_type;
 		gpio_keys[n_buttons].code = info->event_code;
@@ -309,23 +326,26 @@ static int soc_button_remove(struct platform_device *pdev)
 static int soc_button_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	const struct acpi_device_id *id;
-	struct soc_button_info *button_info;
+	const struct soc_device_data *device_data;
+	const struct soc_button_info *button_info;
 	struct soc_button_data *priv;
 	struct platform_device *pd;
 	int i;
 	int error;
 
-	id = acpi_match_device(dev->driver->acpi_match_table, dev);
-	if (!id)
-		return -ENODEV;
+	device_data = acpi_device_get_match_data(dev);
+	if (device_data && device_data->check) {
+		error = device_data->check(dev);
+		if (error)
+			return error;
+	}
 
-	if (!id->driver_data) {
+	if (device_data && device_data->button_info) {
+		button_info = device_data->button_info;
+	} else {
 		button_info = soc_button_get_button_info(dev);
 		if (IS_ERR(button_info))
 			return PTR_ERR(button_info);
-	} else {
-		button_info = (struct soc_button_info *)id->driver_data;
 	}
 
 	error = gpiod_count(dev, NULL);
@@ -357,8 +377,8 @@ static int soc_button_probe(struct platform_device *pdev)
 	if (!priv->children[0] && !priv->children[1])
 		return -ENODEV;
 
-	if (!id->driver_data)
-		devm_kfree(dev, button_info);
+	if (!device_data || !device_data->button_info)
+		devm_kfree(dev, (void *)button_info);
 
 	return 0;
 }
@@ -368,7 +388,7 @@ static int soc_button_probe(struct platform_device *pdev)
  * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
  * Platforms"
  */
-static struct soc_button_info soc_button_PNP0C40[] = {
+static const struct soc_button_info soc_button_PNP0C40[] = {
 	{ "power", 0, EV_KEY, KEY_POWER, false, true },
 	{ "home", 1, EV_KEY, KEY_LEFTMETA, false, true },
 	{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
@@ -377,9 +397,77 @@ static struct soc_button_info soc_button_PNP0C40[] = {
 	{ }
 };
 
+static const struct soc_device_data soc_device_PNP0C40 = {
+	.button_info = soc_button_PNP0C40,
+};
+
+/*
+ * Special device check for Surface Book 2 and Surface Pro (2017).
+ * Both, the Surface Pro 4 (surfacepro3_button.c) and the above mentioned
+ * devices use MSHW0040 for power and volume buttons, however the way they
+ * have to be addressed differs. Make sure that we only load this drivers
+ * for the correct devices by checking the OEM Platform Revision provided by
+ * the _DSM method.
+ */
+#define MSHW0040_DSM_REVISION		0x01
+#define MSHW0040_DSM_GET_OMPR		0x02	// get OEM Platform Revision
+static const guid_t MSHW0040_DSM_UUID =
+	GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65,
+		  0x49, 0x80, 0x35);
+
+static int soc_device_check_MSHW0040(struct device *dev)
+{
+	acpi_handle handle = ACPI_HANDLE(dev);
+	union acpi_object *result;
+	u64 oem_platform_rev = 0;	// valid revisions are nonzero
+
+	// get OEM platform revision
+	result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
+					 MSHW0040_DSM_REVISION,
+					 MSHW0040_DSM_GET_OMPR, NULL,
+					 ACPI_TYPE_INTEGER);
+
+	if (result) {
+		oem_platform_rev = result->integer.value;
+		ACPI_FREE(result);
+	}
+
+	/*
+	 * If the revision is zero here, the _DSM evaluation has failed. This
+	 * indicates that we have a Pro 4 or Book 1 and this driver should not
+	 * be used.
+	 */
+	if (oem_platform_rev == 0)
+		return -ENODEV;
+
+	dev_dbg(dev, "OEM Platform Revision %llu\n", oem_platform_rev);
+
+	return 0;
+}
+
+/*
+ * Button infos for Microsoft Surface Book 2 and Surface Pro (2017).
+ * Obtained from DSDT/testing.
+ */
+static const struct soc_button_info soc_button_MSHW0040[] = {
+	{ "power", 0, EV_KEY, KEY_POWER, false, true },
+	{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
+	{ "volume_down", 4, EV_KEY, KEY_VOLUMEDOWN, true, false },
+	{ }
+};
+
+static const struct soc_device_data soc_device_MSHW0040 = {
+	.button_info = soc_button_MSHW0040,
+	.check = soc_device_check_MSHW0040,
+};
+
 static const struct acpi_device_id soc_button_acpi_match[] = {
-	{ "PNP0C40", (unsigned long)soc_button_PNP0C40 },
+	{ "PNP0C40", (unsigned long)&soc_device_PNP0C40 },
 	{ "ACPI0011", 0 },
+
+	/* Microsoft Surface Devices (5th and 6th generation) */
+	{ "MSHW0040", (unsigned long)&soc_device_MSHW0040 },
+
 	{ }
 };
 
diff --git a/drivers/platform/x86/surfacepro3_button.c b/drivers/platform/x86/surfacepro3_button.c
index 1b491690ce07..96627627060e 100644
--- a/drivers/platform/x86/surfacepro3_button.c
+++ b/drivers/platform/x86/surfacepro3_button.c
@@ -24,6 +24,12 @@
 #define SURFACE_BUTTON_OBJ_NAME		"VGBI"
 #define SURFACE_BUTTON_DEVICE_NAME	"Surface Pro 3/4 Buttons"
 
+#define MSHW0040_DSM_REVISION		0x01
+#define MSHW0040_DSM_GET_OMPR		0x02	// get OEM Platform Revision
+static const guid_t MSHW0040_DSM_UUID =
+	GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65,
+		  0x49, 0x80, 0x35);
+
 #define SURFACE_BUTTON_NOTIFY_TABLET_MODE	0xc8
 
 #define SURFACE_BUTTON_NOTIFY_PRESS_POWER	0xc6
@@ -146,6 +152,44 @@ static int surface_button_resume(struct device *dev)
 }
 #endif
 
+/*
+ * Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device
+ * ID (MSHW0040) for the power/volume buttons. Make sure this is the right
+ * device by checking for the _DSM method and OEM Platform Revision.
+ *
+ * Returns true if the driver should bind to this device, i.e. the device is
+ * either MSWH0028 (Pro 3) or MSHW0040 on a Pro 4 or Book 1.
+ */
+static bool surface_button_check_MSHW0040(struct acpi_device *dev)
+{
+	acpi_handle handle = dev->handle;
+	union acpi_object *result;
+	u64 oem_platform_rev = 0;	// valid revisions are nonzero
+
+	// get OEM platform revision
+	result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
+					 MSHW0040_DSM_REVISION,
+					 MSHW0040_DSM_GET_OMPR,
+					 NULL, ACPI_TYPE_INTEGER);
+
+	/*
+	 * If evaluating the _DSM fails, the method is not present. This means
+	 * that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we
+	 * should use this driver. We use revision 0 indicating it is
+	 * unavailable.
+	 */
+
+	if (result) {
+		oem_platform_rev = result->integer.value;
+		ACPI_FREE(result);
+	}
+
+	dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);
+
+	return oem_platform_rev == 0;
+}
+
+
 static int surface_button_add(struct acpi_device *device)
 {
 	struct surface_button *button;
@@ -158,6 +202,9 @@ static int surface_button_add(struct acpi_device *device)
 	    strlen(SURFACE_BUTTON_OBJ_NAME)))
 		return -ENODEV;
 
+	if (!surface_button_check_MSHW0040(device))
+		return -ENODEV;
+
 	button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 	if (!button)
 		return -ENOMEM;
-- 
2.26.2