linux-surface/patches/4.19/0003-buttons.patch

From 65be92a4e7a1373a08dc1d75892dc6cafef830d0 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 2 Jul 2019 23:49:56 +0200
Subject: [PATCH 03/12] buttons

---
 drivers/input/misc/soc_button_array.c     | 151 ++++++++++++++++++++--
 drivers/platform/x86/surfacepro3_button.c |  38 ++++++
 2 files changed, 176 insertions(+), 13 deletions(-)

diff --git a/drivers/input/misc/soc_button_array.c b/drivers/input/misc/soc_button_array.c
index 55cd6e0b409c..171d8a5c8bfd 100644
--- a/drivers/input/misc/soc_button_array.c
+++ b/drivers/input/misc/soc_button_array.c
@@ -29,6 +29,17 @@ struct soc_button_info {
 	bool wakeup;
 };
 
+/**
+ * struct soc_device_data - driver data for different device types
+ * @button_info: specifications of buttons, if NULL specification is assumed to
+ *               be present in _DSD
+ * @check: device-specific check (NULL means all will be accepted)
+ */
+struct soc_device_data {
+	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 +102,12 @@ 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 == -EPROBE_DEFER) {
+			error = -EPROBE_DEFER;
+			goto err_free_mem;
+		} else if (!gpio_is_valid(gpio)) {
 			continue;
+		}
 
 		gpio_keys[n_buttons].type = info->event_type;
 		gpio_keys[n_buttons].code = info->event_code;
@@ -310,6 +325,7 @@ 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;
@@ -320,18 +336,20 @@ 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) {
+		error = device_data->check(dev);
+		if (error)
+			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);
-	if (error < 0) {
-		dev_dbg(dev, "no GPIO attached, ignoring...\n");
-		return -ENODEV;
 	}
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
@@ -357,12 +375,32 @@ 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;
 }
 
+
+static int soc_device_check_generic(struct device *dev)
+{
+	int gpios;
+
+	gpios = gpiod_count(dev, NULL);
+	if (gpios < 0) {
+		dev_dbg(dev, "no GPIO attached, ignoring...\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static struct soc_device_data soc_device_ACPI0011 = {
+	.button_info = NULL,
+	.check = soc_device_check_generic,
+};
+
+
 /*
  * Definition of buttons on the tablet. The ACPI index of each button
  * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
@@ -377,9 +415,96 @@ static struct soc_button_info soc_button_PNP0C40[] = {
 	{ }
 };
 
+static struct soc_device_data soc_device_PNP0C40 = {
+	.button_info = soc_button_PNP0C40,
+	.check = soc_device_check_generic,
+};
+
+
+/*
+ * 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);
+
+#ifdef CONFIG_ACPI
+
+static int soc_device_check_MSHW0040(struct device *dev)
+{
+	acpi_handle handle = ACPI_HANDLE(dev);
+	union acpi_object *result;
+	u64 oem_platform_rev = 0;
+	int gpios;
+
+	// 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 (oem_platform_rev == 0)
+		return -ENODEV;
+
+	dev_dbg(dev, "OEM Platform Revision %llu\n", oem_platform_rev);
+
+	/*
+	 * We are _really_ expecting GPIOs here. If we do not get any, this
+	 * means the GPIO driver has not been loaded yet (which can happen).
+	 * Try again later.
+	 */
+	gpios = gpiod_count(dev, NULL);
+	if (gpios < 0)
+		return -EPROBE_DEFER;
+
+	return 0;
+}
+
+#else   /* CONFIG_ACPI */
+
+static int soc_device_check_MSHW0040(struct device *dev)
+{
+    return -ENODEV;
+}
+
+#endif  /* CONFIG_ACPI */
+
+/*
+ * Button infos for Microsoft Surface Book 2 and Surface Pro (2017).
+ * Obtained from DSDT/testing.
+ */
+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 },
-	{ "ACPI0011", 0 },
+	{ "PNP0C40", (unsigned long)&soc_device_PNP0C40 },
+	{ "ACPI0011", (unsigned long)&soc_device_ACPI0011 },
+
+	/* 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..eaec30380b11 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 +152,34 @@ 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.
+ */
+static int surface_button_check_MSHW0040(struct acpi_device *dev)
+{
+	acpi_handle handle = dev->handle;
+	union acpi_object *result;
+	u64 oem_platform_rev = 0;
+
+	// 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);
+	}
+
+	dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);
+
+	return oem_platform_rev == 0 ? 0 : -ENODEV;
+}
+
+
 static int surface_button_add(struct acpi_device *device)
 {
 	struct surface_button *button;
@@ -158,6 +192,10 @@ static int surface_button_add(struct acpi_device *device)
 	    strlen(SURFACE_BUTTON_OBJ_NAME)))
 		return -ENODEV;
 
+	error = surface_button_check_MSHW0040(device);
+	if (error)
+		return error;
+
 	button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 	if (!button)
 		return -ENOMEM;
-- 
2.22.0