Input: add RAVE SP Powerbutton driver

Add driver that properly handles input event emitted by RAVE SP
devices.

Reviewed-by: Lucas Stach <[e-mail]>
Signed-off-by: Andrey Smirnov <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/input/zii,rave-sp-pwrbutton.txt

···
+Zodiac Inflight Innovations RAVE Supervisory Processor Power Button Bindings
+
+RAVE SP input device is a "MFD cell" device corresponding to power
+button functionality of RAVE Supervisory Processor. It is expected
+that its Device Tree node is specified as a child of the node
+corresponding to the parent RAVE SP device (as documented in
+Documentation/devicetree/bindings/mfd/zii,rave-sp.txt)
+
+Required properties:
+
+- compatible: Should be "zii,rave-sp-pwrbutton"
+
+Example:
+
+	rave-sp {
+		compatible = "zii,rave-sp-rdu1";
+		current-speed = <38400>;
+
+		pwrbutton {
+			compatible = "zii,rave-sp-pwrbutton";
+		};
+	}

drivers/input/misc/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called hisi_powerkey.
 
+config INPUT_RAVE_SP_PWRBUTTON
+	tristate "RAVE SP Power button Driver"
+	depends on RAVE_SP_CORE
+	help
+	  Say Y here if you want to enable power key reporting from RAVE SP
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rave-sp-pwrbutton.
+
 endif

drivers/input/misc/Makefile

···
 obj-$(CONFIG_INPUT_POWERMATE)		+= powermate.o
 obj-$(CONFIG_INPUT_PWM_BEEPER)		+= pwm-beeper.o
 obj-$(CONFIG_INPUT_PWM_VIBRA)		+= pwm-vibra.o
+obj-$(CONFIG_INPUT_RAVE_SP_PWRBUTTON)	+= rave-sp-pwrbutton.o
 obj-$(CONFIG_INPUT_RB532_BUTTON)	+= rb532_button.o
 obj-$(CONFIG_INPUT_REGULATOR_HAPTIC)	+= regulator-haptic.o
 obj-$(CONFIG_INPUT_RETU_PWRBUTTON)	+= retu-pwrbutton.o

drivers/input/misc/rave-sp-pwrbutton.c

···
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Power Button driver for RAVE SP
+//
+// Copyright (C) 2017 Zodiac Inflight Innovations
+//
+//
+
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/rave-sp.h>
+#include <linux/platform_device.h>
+
+#define RAVE_SP_EVNT_BUTTON_PRESS	(RAVE_SP_EVNT_BASE + 0x00)
+
+struct rave_sp_power_button {
+	struct input_dev *idev;
+	struct notifier_block nb;
+};
+
+static int rave_sp_power_button_event(struct notifier_block *nb,
+				      unsigned long action, void *data)
+{
+	struct rave_sp_power_button *pb =
+		container_of(nb, struct rave_sp_power_button, nb);
+	const u8 event = rave_sp_action_unpack_event(action);
+	const u8 value = rave_sp_action_unpack_value(action);
+	struct input_dev *idev = pb->idev;
+
+	if (event == RAVE_SP_EVNT_BUTTON_PRESS) {
+		input_report_key(idev, KEY_POWER, value);
+		input_sync(idev);
+
+		return NOTIFY_STOP;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int rave_sp_pwrbutton_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rave_sp_power_button *pb;
+	struct input_dev *idev;
+	int error;
+
+	pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
+	if (!pb)
+		return -ENOMEM;
+
+	idev = devm_input_allocate_device(dev);
+	if (!idev)
+		return -ENOMEM;
+
+	idev->name = pdev->name;
+
+	input_set_capability(idev, EV_KEY, KEY_POWER);
+
+	error = input_register_device(idev);
+	if (error)
+		return error;
+
+	pb->idev = idev;
+	pb->nb.notifier_call = rave_sp_power_button_event;
+	pb->nb.priority = 128;
+
+	error = devm_rave_sp_register_event_notifier(dev, &pb->nb);
+	if (error)
+		return error;
+
+	return 0;
+}
+
+static const struct of_device_id rave_sp_pwrbutton_of_match[] = {
+	{ .compatible = "zii,rave-sp-pwrbutton" },
+	{}
+};
+
+static struct platform_driver rave_sp_pwrbutton_driver = {
+	.probe = rave_sp_pwrbutton_probe,
+	.driver	= {
+		.name = KBUILD_MODNAME,
+		.of_match_table = rave_sp_pwrbutton_of_match,
+	},
+};
+module_platform_driver(rave_sp_pwrbutton_driver);
+
+MODULE_DEVICE_TABLE(of, rave_sp_pwrbutton_of_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andrey Vostrikov <[e-mail]>");
+MODULE_AUTHOR("Nikita Yushchenko <[e-mail]>");
+MODULE_AUTHOR("Andrey Smirnov <[e-mail]>");
+MODULE_DESCRIPTION("RAVE SP Power Button driver");