/*
 * OnKey device driver for DA9063
 * Copyright (C) 2015  Dialog Semiconductor Ltd.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>
#include <linux/regmap.h>
#include <linux/of.h>
#include <linux/mfd/da9063/core.h>
#include <linux/mfd/da9063/pdata.h>
#include <linux/mfd/da9063/registers.h>

struct da9063_onkey {
	struct da9063 *hw;
	struct delayed_work work;
	struct input_dev *input;
	struct device *dev;
	bool key_power;
};

static void da9063_poll_on(struct work_struct *work)
{
	struct da9063_onkey *onkey = container_of(work, struct da9063_onkey,
						  work.work);
	unsigned int val;
	int fault_log = 0;
	bool poll = true;
	int error;

	/* Poll to see when the pin is released */
	error = regmap_read(onkey->hw->regmap, DA9063_REG_STATUS_A, &val);
	if (error) {
		dev_err(onkey->dev,
			"Failed to read ON status: %d\n", error);
		goto err_poll;
	}

	if (!(val & DA9063_NONKEY)) {
		error = regmap_update_bits(onkey->hw->regmap,
					   DA9063_REG_CONTROL_B,
					   DA9063_NONKEY_LOCK, 0);
		if (error) {
			dev_err(onkey->dev,
				"Failed to reset the Key Delay %d\n", error);
			goto err_poll;
		}

		input_report_key(onkey->input, KEY_POWER, 0);
		input_sync(onkey->input);

		poll = false;
	}

	/*
	 * If the fault log KEY_RESET is detected, then clear it
	 * and shut down the system.
	 */
	error = regmap_read(onkey->hw->regmap,
			    DA9063_REG_FAULT_LOG, &fault_log);
	if (error) {
		dev_warn(&onkey->input->dev,
			 "Cannot read FAULT_LOG: %d\n", error);
	} else if (fault_log & DA9063_KEY_RESET) {
		error = regmap_write(onkey->hw->regmap,
				     DA9063_REG_FAULT_LOG,
				     DA9063_KEY_RESET);
		if (error) {
			dev_warn(&onkey->input->dev,
				 "Cannot reset KEY_RESET fault log: %d\n",
				 error);
		} else {
			/* at this point we do any S/W housekeeping
			 * and then send shutdown command
			 */
			dev_dbg(&onkey->input->dev,
				 "Sending SHUTDOWN to DA9063 ...\n");
			error = regmap_write(onkey->hw->regmap,
					     DA9063_REG_CONTROL_F,
					     DA9063_SHUTDOWN);
			if (error)
				dev_err(&onkey->input->dev,
					"Cannot SHUTDOWN DA9063: %d\n",
					error);
		}
	}

err_poll:
	if (poll)
		schedule_delayed_work(&onkey->work, msecs_to_jiffies(50));
}

static irqreturn_t da9063_onkey_irq_handler(int irq, void *data)
{
	struct da9063_onkey *onkey = data;
	unsigned int val;
	int error;

	error = regmap_read(onkey->hw->regmap, DA9063_REG_STATUS_A, &val);
	if (onkey->key_power && !error && (val & DA9063_NONKEY)) {
		input_report_key(onkey->input, KEY_POWER, 1);
		input_sync(onkey->input);
		schedule_delayed_work(&onkey->work, 0);
		dev_dbg(onkey->dev, "KEY_POWER pressed.\n");
	} else {
		input_report_key(onkey->input, KEY_SLEEP, 1);
		input_sync(onkey->input);
		input_report_key(onkey->input, KEY_SLEEP, 0);
		input_sync(onkey->input);
		dev_dbg(onkey->dev, "KEY_SLEEP pressed.\n");
	}

	return IRQ_HANDLED;
}

static void da9063_cancel_poll(void *data)
{
	struct da9063_onkey *onkey = data;

	cancel_delayed_work_sync(&onkey->work);
}

static int da9063_onkey_probe(struct platform_device *pdev)
{
	struct da9063 *da9063 = dev_get_drvdata(pdev->dev.parent);
	struct da9063_pdata *pdata = dev_get_platdata(da9063->dev);
	struct da9063_onkey *onkey;
	int irq;
	int error;

	onkey = devm_kzalloc(&pdev->dev, sizeof(struct da9063_onkey),
			     GFP_KERNEL);
	if (!onkey) {
		dev_err(&pdev->dev, "Failed to allocate memory.\n");
		return -ENOMEM;
	}

	onkey->dev = &pdev->dev;
	onkey->hw = da9063;

	if (pdata)
		onkey->key_power = pdata->key_power;
	else
		onkey->key_power =
			!of_property_read_bool(pdev->dev.of_node,
					       "dlg,disable-key-power");

	onkey->input = devm_input_allocate_device(&pdev->dev);
	if (!onkey->input) {
		dev_err(&pdev->dev, "Failed to allocated input device.\n");
		return -ENOMEM;
	}

	onkey->input->name = DA9063_DRVNAME_ONKEY;
	onkey->input->phys = DA9063_DRVNAME_ONKEY "/input0";
	onkey->input->dev.parent = &pdev->dev;

	if (onkey->key_power)
		input_set_capability(onkey->input, EV_KEY, KEY_POWER);

	input_set_capability(onkey->input, EV_KEY, KEY_SLEEP);

	INIT_DELAYED_WORK(&onkey->work, da9063_poll_on);

	error = devm_add_action(&pdev->dev, da9063_cancel_poll, onkey);
	if (error) {
		dev_err(&pdev->dev,
			"Failed to add cancel poll action: %d\n",
			error);
		return error;
	}

	irq = platform_get_irq_byname(pdev, "ONKEY");
	if (irq < 0) {
		error = irq;
		dev_err(&pdev->dev, "Failed to get platform IRQ: %d\n", error);
		return error;
	}

	error = devm_request_threaded_irq(&pdev->dev, irq,
					  NULL, da9063_onkey_irq_handler,
					  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
					  "ONKEY", onkey);
	if (error) {
		dev_err(&pdev->dev,
			"Failed to request IRQ %d: %d\n", irq, error);
		return error;
	}

	error = input_register_device(onkey->input);
	if (error) {
		dev_err(&pdev->dev,
			"Failed to register input device: %d\n", error);
		return error;
	}

	platform_set_drvdata(pdev, onkey);
	return 0;
}

static struct platform_driver da9063_onkey_driver = {
	.probe	= da9063_onkey_probe,
	.driver	= {
		.name	= DA9063_DRVNAME_ONKEY,
	},
};
module_platform_driver(da9063_onkey_driver);

MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
MODULE_DESCRIPTION("Onkey device driver for Dialog DA9063");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DA9063_DRVNAME_ONKEY);