linux-surface/patches/4.18/0003-buttons.patch

From ac9ac2a05180af9e356f2f4d6840b132b1fb45f7 Mon Sep 17 00:00:00 2001
From: qzed <qzed@users.noreply.github.com>
Date: Mon, 24 Dec 2018 14:05:07 +0100
Subject: [PATCH 3/8] buttons

---
 drivers/input/misc/soc_button_array.c     | 67 +++++++++++++++++++++--
 drivers/platform/x86/surfacepro3_button.c |  9 +++
 2 files changed, 70 insertions(+), 6 deletions(-)

diff --git a/drivers/input/misc/soc_button_array.c b/drivers/input/misc/soc_button_array.c
index 23520df7650f..d74f8c3dd54b 100644
--- a/drivers/input/misc/soc_button_array.c
+++ b/drivers/input/misc/soc_button_array.c
@@ -29,12 +29,20 @@ struct soc_button_info {
 	bool wakeup;
 };
 
+struct soc_device_data {
+	/* Button info, may be NULL. */
+	struct soc_button_info *button_info;
+	/* Special device check function, may be NULL. */
+	int (*check)(struct device *);
+};
+
 /*
  * 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
  * buttons into them based on whether the key should be auto repeat.
  */
-#define BUTTON_TYPES	2
+#define BUTTON_TYPES            2
+#define SURFACE_METHOD_DSM      "_DSM"
 
 struct soc_button_data {
 	struct platform_device *children[BUTTON_TYPES];
@@ -310,6 +318,7 @@ static int soc_button_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	const struct acpi_device_id *id;
+	struct soc_device_data *device_data;
 	struct soc_button_info *button_info;
 	struct soc_button_data *priv;
 	struct platform_device *pd;
@@ -320,12 +329,20 @@ static int soc_button_probe(struct platform_device *pdev)
 	if (!id)
 		return -ENODEV;
 
-	if (!id->driver_data) {
+	device_data = (struct soc_device_data *)id->driver_data;
+	if (device_data && device_data->check) {
+		// device dependent check, required for MSHW0040
+		error = device_data->check(dev);
+		if (error != 0)
+			return error;
+	}
+
+	if (device_data && device_data->button_info) {
+		button_info = (struct soc_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);
@@ -357,7 +374,7 @@ static int soc_button_probe(struct platform_device *pdev)
 	if (!priv->children[0] && !priv->children[1])
 		return -ENODEV;
 
-	if (!id->driver_data)
+	if (!device_data || !device_data->button_info)
 		devm_kfree(dev, button_info);
 
 	return 0;
@@ -377,9 +394,47 @@ static struct soc_button_info soc_button_PNP0C40[] = {
 	{ }
 };
 
+static struct soc_device_data soc_device_PNP0C40 = {
+	.button_info = soc_button_PNP0C40,
+	.check = NULL,
+};
+
+/*
+ * 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 if the _DSM method exists.
+ */
+static int soc_device_check_MSHW0040(struct device *dev)
+{
+	if (!acpi_has_method(ACPI_HANDLE(dev), SURFACE_METHOD_DSM))
+		return -ENODEV;
+
+	return 0;
+}
+
+/*
+ * Button infos for Microsoft Surface Book 2 and Surface Pro (2017).
+ * Extracted from DSDT.
+ */
+static 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 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 Book 2 and Surface Pro (2017) */
+	{ "MSHW0040", (unsigned long)&soc_device_MSHW0040 },
 	{ }
 };
 
diff --git a/drivers/platform/x86/surfacepro3_button.c b/drivers/platform/x86/surfacepro3_button.c
index 1b491690ce07..006c94eda7be 100644
--- a/drivers/platform/x86/surfacepro3_button.c
+++ b/drivers/platform/x86/surfacepro3_button.c
@@ -22,6 +22,7 @@
 #define SURFACE_PRO3_BUTTON_HID		"MSHW0028"
 #define SURFACE_PRO4_BUTTON_HID		"MSHW0040"
 #define SURFACE_BUTTON_OBJ_NAME		"VGBI"
+#define SURFACE_METHOD_DSM		"_DSM"
 #define SURFACE_BUTTON_DEVICE_NAME	"Surface Pro 3/4 Buttons"
 
 #define SURFACE_BUTTON_NOTIFY_TABLET_MODE	0xc8
@@ -158,6 +159,14 @@ static int surface_button_add(struct acpi_device *device)
 	    strlen(SURFACE_BUTTON_OBJ_NAME)))
 		return -ENODEV;
 
+	/*
+	 * 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.
+	 */
+	if (acpi_has_method(device->handle, SURFACE_METHOD_DSM))
+		return -ENODEV;
+
 	button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 	if (!button)
 		return -ENOMEM;
-- 
2.20.1