Input: add a new driver for GPIO beeper

This patch adds a new driver for the beeper controlled via GPIO pin.
The driver does not depend on the architecture and is positioned as
a replacement for the specific drivers that are used for this function.

Signed-off-by: Alexander Shiyan <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/input/gpio-beeper.txt

···
+* GPIO beeper device tree bindings
+
+Register a beeper connected to GPIO pin.
+
+Required properties:
+- compatible:	Should be "gpio-beeper".
+- gpios:	From common gpio binding; gpio connection to beeper enable pin.
+
+Example:
+	beeper: beeper {
+		compatible = "gpio-beeper";
+		gpios = <&gpio3 23 GPIO_ACTIVE_HIGH>;
+	};

drivers/input/misc/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called gp2ap002a00f.
 
+config INPUT_GPIO_BEEPER
+	tristate "Generic GPIO Beeper support"
+	depends on OF_GPIO
+	help
+	  Say Y here if you have a beeper connected to a GPIO pin.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called gpio-beeper.
+
 config INPUT_GPIO_TILT_POLLED
 	tristate "Polled GPIO tilt switch"
 	depends on GPIOLIB

drivers/input/misc/Makefile

···
 obj-$(CONFIG_INPUT_DA9055_ONKEY)	+= da9055_onkey.o
 obj-$(CONFIG_INPUT_DM355EVM)		+= dm355evm_keys.o
 obj-$(CONFIG_INPUT_GP2A)		+= gp2ap002a00f.o
+obj-$(CONFIG_INPUT_GPIO_BEEPER)		+= gpio-beeper.o
 obj-$(CONFIG_INPUT_GPIO_TILT_POLLED)	+= gpio_tilt_polled.o
 obj-$(CONFIG_HP_SDC_RTC)		+= hp_sdc_rtc.o
 obj-$(CONFIG_INPUT_IMS_PCU)		+= ims-pcu.o

drivers/input/misc/gpio-beeper.c

···
+/*
+ * Generic GPIO beeper driver
+ *
+ * Copyright (C) 2013 Alexander Shiyan <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/workqueue.h>
+#include <linux/platform_device.h>
+
+#define BEEPER_MODNAME		"gpio-beeper"
+
+struct gpio_beeper {
+	struct work_struct	work;
+	int			gpio;
+	bool			active_low;
+	bool			beeping;
+};
+
+static void gpio_beeper_toggle(struct gpio_beeper *beep, bool on)
+{
+	gpio_set_value_cansleep(beep->gpio, on ^ beep->active_low);
+}
+
+static void gpio_beeper_work(struct work_struct *work)
+{
+	struct gpio_beeper *beep = container_of(work, struct gpio_beeper, work);
+
+	gpio_beeper_toggle(beep, beep->beeping);
+}
+
+static int gpio_beeper_event(struct input_dev *dev, unsigned int type,
+			     unsigned int code, int value)
+{
+	struct gpio_beeper *beep = input_get_drvdata(dev);
+
+	if (type != EV_SND || code != SND_BELL)
+		return -ENOTSUPP;
+
+	if (value < 0)
+		return -EINVAL;
+
+	beep->beeping = value;
+	/* Schedule work to actually turn the beeper on or off */
+	schedule_work(&beep->work);
+
+	return 0;
+}
+
+static void gpio_beeper_close(struct input_dev *input)
+{
+	struct gpio_beeper *beep = input_get_drvdata(input);
+
+	cancel_work_sync(&beep->work);
+	gpio_beeper_toggle(beep, false);
+}
+
+static int gpio_beeper_probe(struct platform_device *pdev)
+{
+	struct gpio_beeper *beep;
+	enum of_gpio_flags flags;
+	struct input_dev *input;
+	unsigned long gflags;
+	int err;
+
+	beep = devm_kzalloc(&pdev->dev, sizeof(*beep), GFP_KERNEL);
+	if (!beep)
+		return -ENOMEM;
+
+	beep->gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
+	if (!gpio_is_valid(beep->gpio))
+		return beep->gpio;
+
+	input = devm_input_allocate_device(&pdev->dev);
+	if (!input)
+		return -ENOMEM;
+
+	INIT_WORK(&beep->work, gpio_beeper_work);
+
+	input->name		= pdev->name;
+	input->id.bustype	= BUS_HOST;
+	input->id.vendor	= 0x0001;
+	input->id.product	= 0x0001;
+	input->id.version	= 0x0100;
+	input->close		= gpio_beeper_close;
+	input->event		= gpio_beeper_event;
+
+	input_set_capability(input, EV_SND, SND_BELL);
+
+	beep->active_low = flags & OF_GPIO_ACTIVE_LOW;
+	gflags = beep->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
+
+	err = devm_gpio_request_one(&pdev->dev, beep->gpio, gflags, pdev->name);
+	if (err)
+		return err;
+
+	input_set_drvdata(input, beep);
+
+	return input_register_device(input);
+}
+
+static struct of_device_id gpio_beeper_of_match[] = {
+	{ .compatible = BEEPER_MODNAME, },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, gpio_beeper_of_match);
+
+static struct platform_driver gpio_beeper_platform_driver = {
+	.driver	= {
+		.name		= BEEPER_MODNAME,
+		.owner		= THIS_MODULE,
+		.of_match_table	= gpio_beeper_of_match,
+	},
+	.probe	= gpio_beeper_probe,
+};
+module_platform_driver(gpio_beeper_platform_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alexander Shiyan <[e-mail]>");
+MODULE_DESCRIPTION("Generic GPIO beeper driver");