1 files changed, 499 insertions, 0 deletions
diff --git a/drivers/platform/x86/dell-rbtn.c b/drivers/platform/x86/dell-rbtn.c
new file mode 100644
index 000000000..a89fad47f
--- /dev/null
+++ b/drivers/platform/x86/dell-rbtn.c
@@ -0,0 +1,499 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+    Dell Airplane Mode Switch driver
+    Copyright (C) 2014-2015  Pali Rohár <pali@kernel.org>
+
+*/
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/rfkill.h>
+#include <linux/input.h>
+
+#include "dell-rbtn.h"
+
+enum rbtn_type {
+	RBTN_UNKNOWN,
+	RBTN_TOGGLE,
+	RBTN_SLIDER,
+};
+
+struct rbtn_data {
+	enum rbtn_type type;
+	struct rfkill *rfkill;
+	struct input_dev *input_dev;
+	bool suspended;
+};
+
+
+/*
+ * acpi functions
+ */
+
+static enum rbtn_type rbtn_check(struct acpi_device *device)
+{
+	unsigned long long output;
+	acpi_status status;
+
+	status = acpi_evaluate_integer(device->handle, "CRBT", NULL, &output);
+	if (ACPI_FAILURE(status))
+		return RBTN_UNKNOWN;
+
+	switch (output) {
+	case 0:
+	case 1:
+		return RBTN_TOGGLE;
+	case 2:
+	case 3:
+		return RBTN_SLIDER;
+	default:
+		return RBTN_UNKNOWN;
+	}
+}
+
+static int rbtn_get(struct acpi_device *device)
+{
+	unsigned long long output;
+	acpi_status status;
+
+	status = acpi_evaluate_integer(device->handle, "GRBT", NULL, &output);
+	if (ACPI_FAILURE(status))
+		return -EINVAL;
+
+	return !output;
+}
+
+static int rbtn_acquire(struct acpi_device *device, bool enable)
+{
+	struct acpi_object_list input;
+	union acpi_object param;
+	acpi_status status;
+
+	param.type = ACPI_TYPE_INTEGER;
+	param.integer.value = enable;
+	input.count = 1;
+	input.pointer = &param;
+
+	status = acpi_evaluate_object(device->handle, "ARBT", &input, NULL);
+	if (ACPI_FAILURE(status))
+		return -EINVAL;
+
+	return 0;
+}
+
+
+/*
+ * rfkill device
+ */
+
+static void rbtn_rfkill_query(struct rfkill *rfkill, void *data)
+{
+	struct acpi_device *device = data;
+	int state;
+
+	state = rbtn_get(device);
+	if (state < 0)
+		return;
+
+	rfkill_set_states(rfkill, state, state);
+}
+
+static int rbtn_rfkill_set_block(void *data, bool blocked)
+{
+	/* NOTE: setting soft rfkill state is not supported */
+	return -EINVAL;
+}
+
+static const struct rfkill_ops rbtn_ops = {
+	.query = rbtn_rfkill_query,
+	.set_block = rbtn_rfkill_set_block,
+};
+
+static int rbtn_rfkill_init(struct acpi_device *device)
+{
+	struct rbtn_data *rbtn_data = device->driver_data;
+	int ret;
+
+	if (rbtn_data->rfkill)
+		return 0;
+
+	/*
+	 * NOTE: rbtn controls all radio devices, not only WLAN
+	 *       but rfkill interface does not support "ANY" type
+	 *       so "WLAN" type is used
+	 */
+	rbtn_data->rfkill = rfkill_alloc("dell-rbtn", &device->dev,
+					 RFKILL_TYPE_WLAN, &rbtn_ops, device);
+	if (!rbtn_data->rfkill)
+		return -ENOMEM;
+
+	ret = rfkill_register(rbtn_data->rfkill);
+	if (ret) {
+		rfkill_destroy(rbtn_data->rfkill);
+		rbtn_data->rfkill = NULL;
+		return ret;
+	}
+
+	return 0;
+}
+
+static void rbtn_rfkill_exit(struct acpi_device *device)
+{
+	struct rbtn_data *rbtn_data = device->driver_data;
+
+	if (!rbtn_data->rfkill)
+		return;
+
+	rfkill_unregister(rbtn_data->rfkill);
+	rfkill_destroy(rbtn_data->rfkill);
+	rbtn_data->rfkill = NULL;
+}
+
+static void rbtn_rfkill_event(struct acpi_device *device)
+{
+	struct rbtn_data *rbtn_data = device->driver_data;
+
+	if (rbtn_data->rfkill)
+		rbtn_rfkill_query(rbtn_data->rfkill, device);
+}
+
+
+/*
+ * input device
+ */
+
+static int rbtn_input_init(struct rbtn_data *rbtn_data)
+{
+	int ret;
+
+	rbtn_data->input_dev = input_allocate_device();
+	if (!rbtn_data->input_dev)
+		return -ENOMEM;
+
+	rbtn_data->input_dev->name = "DELL Wireless hotkeys";
+	rbtn_data->input_dev->phys = "dellabce/input0";
+	rbtn_data->input_dev->id.bustype = BUS_HOST;
+	rbtn_data->input_dev->evbit[0] = BIT(EV_KEY);
+	set_bit(KEY_RFKILL, rbtn_data->input_dev->keybit);
+
+	ret = input_register_device(rbtn_data->input_dev);
+	if (ret) {
+		input_free_device(rbtn_data->input_dev);
+		rbtn_data->input_dev = NULL;
+		return ret;
+	}
+
+	return 0;
+}
+
+static void rbtn_input_exit(struct rbtn_data *rbtn_data)
+{
+	input_unregister_device(rbtn_data->input_dev);
+	rbtn_data->input_dev = NULL;
+}
+
+static void rbtn_input_event(struct rbtn_data *rbtn_data)
+{
+	input_report_key(rbtn_data->input_dev, KEY_RFKILL, 1);
+	input_sync(rbtn_data->input_dev);
+	input_report_key(rbtn_data->input_dev, KEY_RFKILL, 0);
+	input_sync(rbtn_data->input_dev);
+}
+
+
+/*
+ * acpi driver
+ */
+
+static int rbtn_add(struct acpi_device *device);
+static int rbtn_remove(struct acpi_device *device);
+static void rbtn_notify(struct acpi_device *device, u32 event);
+
+static const struct acpi_device_id rbtn_ids[] = {
+	{ "DELRBTN", 0 },
+	{ "DELLABCE", 0 },
+
+	/*
+	 * This driver can also handle the "DELLABC6" device that
+	 * appears on the XPS 13 9350, but that device is disabled by
+	 * the DSDT unless booted with acpi_osi="!Windows 2012"
+	 * acpi_osi="!Windows 2013".
+	 *
+	 * According to Mario at Dell:
+	 *
+	 *  DELLABC6 is a custom interface that was created solely to
+	 *  have airplane mode support for Windows 7.  For Windows 10
+	 *  the proper interface is to use that which is handled by
+	 *  intel-hid. A OEM airplane mode driver is not used.
+	 *
+	 *  Since the kernel doesn't identify as Windows 7 it would be
+	 *  incorrect to do attempt to use that interface.
+	 *
+	 * Even if we override _OSI and bind to DELLABC6, we end up with
+	 * inconsistent behavior in which userspace can get out of sync
+	 * with the rfkill state as it conflicts with events from
+	 * intel-hid.
+	 *
+	 * The upshot is that it is better to just ignore DELLABC6
+	 * devices.
+	 */
+
+	{ "", 0 },
+};
+
+#ifdef CONFIG_PM_SLEEP
+static void ACPI_SYSTEM_XFACE rbtn_clear_suspended_flag(void *context)
+{
+	struct rbtn_data *rbtn_data = context;
+
+	rbtn_data->suspended = false;
+}
+
+static int rbtn_suspend(struct device *dev)
+{
+	struct acpi_device *device = to_acpi_device(dev);
+	struct rbtn_data *rbtn_data = acpi_driver_data(device);
+
+	rbtn_data->suspended = true;
+
+	return 0;
+}
+
+static int rbtn_resume(struct device *dev)
+{
+	struct acpi_device *device = to_acpi_device(dev);
+	struct rbtn_data *rbtn_data = acpi_driver_data(device);
+	acpi_status status;
+
+	/*
+	 * Upon resume, some BIOSes send an ACPI notification thet triggers
+	 * an unwanted input event. In order to ignore it, we use a flag
+	 * that we set at suspend and clear once we have received the extra
+	 * ACPI notification. Since ACPI notifications are delivered
+	 * asynchronously to drivers, we clear the flag from the workqueue
+	 * used to deliver the notifications. This should be enough
+	 * to have the flag cleared only after we received the extra
+	 * notification, if any.
+	 */
+	status = acpi_os_execute(OSL_NOTIFY_HANDLER,
+			 rbtn_clear_suspended_flag, rbtn_data);
+	if (ACPI_FAILURE(status))
+		rbtn_clear_suspended_flag(rbtn_data);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
+
+static struct acpi_driver rbtn_driver = {
+	.name = "dell-rbtn",
+	.ids = rbtn_ids,
+	.drv.pm = &rbtn_pm_ops,
+	.ops = {
+		.add = rbtn_add,
+		.remove = rbtn_remove,
+		.notify = rbtn_notify,
+	},
+	.owner = THIS_MODULE,
+};
+
+
+/*
+ * notifier export functions
+ */
+
+static bool auto_remove_rfkill = true;
+
+static ATOMIC_NOTIFIER_HEAD(rbtn_chain_head);
+
+static int rbtn_inc_count(struct device *dev, void *data)
+{
+	struct acpi_device *device = to_acpi_device(dev);
+	struct rbtn_data *rbtn_data = device->driver_data;
+	int *count = data;
+
+	if (rbtn_data->type == RBTN_SLIDER)
+		(*count)++;
+
+	return 0;
+}
+
+static int rbtn_switch_dev(struct device *dev, void *data)
+{
+	struct acpi_device *device = to_acpi_device(dev);
+	struct rbtn_data *rbtn_data = device->driver_data;
+	bool enable = data;
+
+	if (rbtn_data->type != RBTN_SLIDER)
+		return 0;
+
+	if (enable)
+		rbtn_rfkill_init(device);
+	else
+		rbtn_rfkill_exit(device);
+
+	return 0;
+}
+
+int dell_rbtn_notifier_register(struct notifier_block *nb)
+{
+	bool first;
+	int count;
+	int ret;
+
+	count = 0;
+	ret = driver_for_each_device(&rbtn_driver.drv, NULL, &count,
+				     rbtn_inc_count);
+	if (ret || count == 0)
+		return -ENODEV;
+
+	first = !rbtn_chain_head.head;
+
+	ret = atomic_notifier_chain_register(&rbtn_chain_head, nb);
+	if (ret != 0)
+		return ret;
+
+	if (auto_remove_rfkill && first)
+		ret = driver_for_each_device(&rbtn_driver.drv, NULL,
+					     (void *)false, rbtn_switch_dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dell_rbtn_notifier_register);
+
+int dell_rbtn_notifier_unregister(struct notifier_block *nb)
+{
+	int ret;
+
+	ret = atomic_notifier_chain_unregister(&rbtn_chain_head, nb);
+	if (ret != 0)
+		return ret;
+
+	if (auto_remove_rfkill && !rbtn_chain_head.head)
+		ret = driver_for_each_device(&rbtn_driver.drv, NULL,
+					     (void *)true, rbtn_switch_dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dell_rbtn_notifier_unregister);
+
+
+/*
+ * acpi driver functions
+ */
+
+static int rbtn_add(struct acpi_device *device)
+{
+	struct rbtn_data *rbtn_data;
+	enum rbtn_type type;
+	int ret = 0;
+
+	type = rbtn_check(device);
+	if (type == RBTN_UNKNOWN) {
+		dev_info(&device->dev, "Unknown device type\n");
+		return -EINVAL;
+	}
+
+	ret = rbtn_acquire(device, true);
+	if (ret < 0) {
+		dev_err(&device->dev, "Cannot enable device\n");
+		return ret;
+	}
+
+	rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
+	if (!rbtn_data)
+		return -ENOMEM;
+
+	rbtn_data->type = type;
+	device->driver_data = rbtn_data;
+
+	switch (rbtn_data->type) {
+	case RBTN_TOGGLE:
+		ret = rbtn_input_init(rbtn_data);
+		break;
+	case RBTN_SLIDER:
+		if (auto_remove_rfkill && rbtn_chain_head.head)
+			ret = 0;
+		else
+			ret = rbtn_rfkill_init(device);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+
+}
+
+static int rbtn_remove(struct acpi_device *device)
+{
+	struct rbtn_data *rbtn_data = device->driver_data;
+
+	switch (rbtn_data->type) {
+	case RBTN_TOGGLE:
+		rbtn_input_exit(rbtn_data);
+		break;
+	case RBTN_SLIDER:
+		rbtn_rfkill_exit(device);
+		break;
+	default:
+		break;
+	}
+
+	rbtn_acquire(device, false);
+	device->driver_data = NULL;
+
+	return 0;
+}
+
+static void rbtn_notify(struct acpi_device *device, u32 event)
+{
+	struct rbtn_data *rbtn_data = device->driver_data;
+
+	/*
+	 * Some BIOSes send a notification at resume.
+	 * Ignore it to prevent unwanted input events.
+	 */
+	if (rbtn_data->suspended) {
+		dev_dbg(&device->dev, "ACPI notification ignored\n");
+		return;
+	}
+
+	if (event != 0x80) {
+		dev_info(&device->dev, "Received unknown event (0x%x)\n",
+			 event);
+		return;
+	}
+
+	switch (rbtn_data->type) {
+	case RBTN_TOGGLE:
+		rbtn_input_event(rbtn_data);
+		break;
+	case RBTN_SLIDER:
+		rbtn_rfkill_event(device);
+		atomic_notifier_call_chain(&rbtn_chain_head, event, device);
+		break;
+	default:
+		break;
+	}
+}
+
+
+/*
+ * module functions
+ */
+
+module_acpi_driver(rbtn_driver);
+
+module_param(auto_remove_rfkill, bool, 0444);
+
+MODULE_PARM_DESC(auto_remove_rfkill, "Automatically remove rfkill devices when "
+				     "other modules start receiving events "
+				     "from this module and re-add them when "
+				     "the last module stops receiving events "
+				     "(default true)");
+MODULE_DEVICE_TABLE(acpi, rbtn_ids);
+MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
+MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
+MODULE_LICENSE("GPL");