/*
 * axp20x power button driver.
 *
 * Copyright (C) 2013 Carlo Caione <carlo@caione.org>
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License. See the file "COPYING" in the main directory of this
 * archive for more details.
 *
 * 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/acpi.h>
#include <linux/errno.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mfd/axp20x.h>
#include <linux/module.h>
#include <linux/platform_data/x86/soc.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#define AXP20X_PEK_STARTUP_MASK		(0xc0)
#define AXP20X_PEK_SHUTDOWN_MASK	(0x03)

struct axp20x_info {
	const struct axp20x_time *startup_time;
	unsigned int startup_mask;
	const struct axp20x_time *shutdown_time;
	unsigned int shutdown_mask;
};

struct axp20x_pek {
	struct axp20x_dev *axp20x;
	struct input_dev *input;
	struct axp20x_info *info;
	int irq_dbr;
	int irq_dbf;
};

struct axp20x_time {
	unsigned int time;
	unsigned int idx;
};

static const struct axp20x_time startup_time[] = {
	{ .time = 128,  .idx = 0 },
	{ .time = 1000, .idx = 2 },
	{ .time = 3000, .idx = 1 },
	{ .time = 2000, .idx = 3 },
};

static const struct axp20x_time axp221_startup_time[] = {
	{ .time = 128,  .idx = 0 },
	{ .time = 1000, .idx = 1 },
	{ .time = 2000, .idx = 2 },
	{ .time = 3000, .idx = 3 },
};

static const struct axp20x_time shutdown_time[] = {
	{ .time = 4000,  .idx = 0 },
	{ .time = 6000,  .idx = 1 },
	{ .time = 8000,  .idx = 2 },
	{ .time = 10000, .idx = 3 },
};

static const struct axp20x_info axp20x_info = {
	.startup_time = startup_time,
	.startup_mask = AXP20X_PEK_STARTUP_MASK,
	.shutdown_time = shutdown_time,
	.shutdown_mask = AXP20X_PEK_SHUTDOWN_MASK,
};

static const struct axp20x_info axp221_info = {
	.startup_time = axp221_startup_time,
	.startup_mask = AXP20X_PEK_STARTUP_MASK,
	.shutdown_time = shutdown_time,
	.shutdown_mask = AXP20X_PEK_SHUTDOWN_MASK,
};

static ssize_t axp20x_show_attr(struct device *dev,
				const struct axp20x_time *time,
				unsigned int mask, char *buf)
{
	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);
	unsigned int val;
	int ret, i;

	ret = regmap_read(axp20x_pek->axp20x->regmap, AXP20X_PEK_KEY, &val);
	if (ret != 0)
		return ret;

	val &= mask;
	val >>= ffs(mask) - 1;

	for (i = 0; i < 4; i++)
		if (val == time[i].idx)
			val = time[i].time;

	return sprintf(buf, "%u\n", val);
}

static ssize_t axp20x_show_attr_startup(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);

	return axp20x_show_attr(dev, axp20x_pek->info->startup_time,
				axp20x_pek->info->startup_mask, buf);
}

static ssize_t axp20x_show_attr_shutdown(struct device *dev,
					 struct device_attribute *attr,
					 char *buf)
{
	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);

	return axp20x_show_attr(dev, axp20x_pek->info->shutdown_time,
				axp20x_pek->info->shutdown_mask, buf);
}

static ssize_t axp20x_store_attr(struct device *dev,
				 const struct axp20x_time *time,
				 unsigned int mask, const char *buf,
				 size_t count)
{
	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);
	char val_str[20];
	size_t len;
	int ret, i;
	unsigned int val, idx = 0;
	unsigned int best_err = UINT_MAX;

	val_str[sizeof(val_str) - 1] = '\0';
	strncpy(val_str, buf, sizeof(val_str) - 1);
	len = strlen(val_str);

	if (len && val_str[len - 1] == '\n')
		val_str[len - 1] = '\0';

	ret = kstrtouint(val_str, 10, &val);
	if (ret)
		return ret;

	for (i = 3; i >= 0; i--) {
		unsigned int err;

		err = abs(time[i].time - val);
		if (err < best_err) {
			best_err = err;
			idx = time[i].idx;
		}

		if (!err)
			break;
	}

	idx <<= ffs(mask) - 1;
	ret = regmap_update_bits(axp20x_pek->axp20x->regmap, AXP20X_PEK_KEY,
				 mask, idx);
	if (ret != 0)
		return -EINVAL;

	return count;
}

static ssize_t axp20x_store_attr_startup(struct device *dev,
					 struct device_attribute *attr,
					 const char *buf, size_t count)
{
	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);

	return axp20x_store_attr(dev, axp20x_pek->info->startup_time,
				 axp20x_pek->info->startup_mask, buf, count);
}

static ssize_t axp20x_store_attr_shutdown(struct device *dev,
					  struct device_attribute *attr,
					  const char *buf, size_t count)
{
	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);

	return axp20x_store_attr(dev, axp20x_pek->info->shutdown_time,
				 axp20x_pek->info->shutdown_mask, buf, count);
}

static DEVICE_ATTR(startup, 0644, axp20x_show_attr_startup,
		   axp20x_store_attr_startup);
static DEVICE_ATTR(shutdown, 0644, axp20x_show_attr_shutdown,
		   axp20x_store_attr_shutdown);

static struct attribute *axp20x_attrs[] = {
	&dev_attr_startup.attr,
	&dev_attr_shutdown.attr,
	NULL,
};
ATTRIBUTE_GROUPS(axp20x);

static irqreturn_t axp20x_pek_irq(int irq, void *pwr)
{
	struct axp20x_pek *axp20x_pek = pwr;
	struct input_dev *idev = axp20x_pek->input;

	if (!idev)
		return IRQ_HANDLED;

	/*
	 * The power-button is connected to ground so a falling edge (dbf)
	 * means it is pressed.
	 */
	if (irq == axp20x_pek->irq_dbf)
		input_report_key(idev, KEY_POWER, true);
	else if (irq == axp20x_pek->irq_dbr)
		input_report_key(idev, KEY_POWER, false);

	input_sync(idev);

	return IRQ_HANDLED;
}

static int axp20x_pek_probe_input_device(struct axp20x_pek *axp20x_pek,
					 struct platform_device *pdev)
{
	struct input_dev *idev;
	int error;

	axp20x_pek->input = devm_input_allocate_device(&pdev->dev);
	if (!axp20x_pek->input)
		return -ENOMEM;

	idev = axp20x_pek->input;

	idev->name = "axp20x-pek";
	idev->phys = "m1kbd/input2";
	idev->dev.parent = &pdev->dev;

	input_set_capability(idev, EV_KEY, KEY_POWER);

	input_set_drvdata(idev, axp20x_pek);

	error = input_register_device(idev);
	if (error) {
		dev_err(&pdev->dev, "Can't register input device: %d\n",
			error);
		return error;
	}

	return 0;
}

static bool axp20x_pek_should_register_input(struct axp20x_pek *axp20x_pek)
{
	if (IS_ENABLED(CONFIG_INPUT_SOC_BUTTON_ARRAY) &&
	    axp20x_pek->axp20x->variant == AXP288_ID) {
		/*
		 * On Cherry Trail platforms (hrv == 3), do not register the
		 * input device if there is an "INTCFD9" or "ACPI0011" gpio
		 * button ACPI device, as that handles the power button too,
		 * and otherwise we end up reporting all presses twice.
		 */
		if (soc_intel_is_cht() &&
				(acpi_dev_present("INTCFD9", NULL, -1) ||
				 acpi_dev_present("ACPI0011", NULL, -1)))
			return false;
	}

	return true;
}

static int axp20x_pek_probe(struct platform_device *pdev)
{
	struct axp20x_pek *axp20x_pek;
	const struct platform_device_id *match = platform_get_device_id(pdev);
	int error;

	if (!match) {
		dev_err(&pdev->dev, "Failed to get platform_device_id\n");
		return -EINVAL;
	}

	axp20x_pek = devm_kzalloc(&pdev->dev, sizeof(struct axp20x_pek),
				  GFP_KERNEL);
	if (!axp20x_pek)
		return -ENOMEM;

	axp20x_pek->axp20x = dev_get_drvdata(pdev->dev.parent);

	axp20x_pek->irq_dbr = platform_get_irq_byname(pdev, "PEK_DBR");
	if (axp20x_pek->irq_dbr < 0)
		return axp20x_pek->irq_dbr;
	axp20x_pek->irq_dbr = regmap_irq_get_virq(
			axp20x_pek->axp20x->regmap_irqc, axp20x_pek->irq_dbr);

	axp20x_pek->irq_dbf = platform_get_irq_byname(pdev, "PEK_DBF");
	if (axp20x_pek->irq_dbf < 0)
		return axp20x_pek->irq_dbf;
	axp20x_pek->irq_dbf = regmap_irq_get_virq(
			axp20x_pek->axp20x->regmap_irqc, axp20x_pek->irq_dbf);

	if (axp20x_pek_should_register_input(axp20x_pek)) {
		error = axp20x_pek_probe_input_device(axp20x_pek, pdev);
		if (error)
			return error;
	}

	axp20x_pek->info = (struct axp20x_info *)match->driver_data;

	error = devm_request_any_context_irq(&pdev->dev, axp20x_pek->irq_dbr,
					     axp20x_pek_irq, 0,
					     "axp20x-pek-dbr", axp20x_pek);
	if (error < 0) {
		dev_err(&pdev->dev, "Failed to request dbr IRQ#%d: %d\n",
			axp20x_pek->irq_dbr, error);
		return error;
	}

	error = devm_request_any_context_irq(&pdev->dev, axp20x_pek->irq_dbf,
					  axp20x_pek_irq, 0,
					  "axp20x-pek-dbf", axp20x_pek);
	if (error < 0) {
		dev_err(&pdev->dev, "Failed to request dbf IRQ#%d: %d\n",
			axp20x_pek->irq_dbf, error);
		return error;
	}

	device_init_wakeup(&pdev->dev, true);

	platform_set_drvdata(pdev, axp20x_pek);

	return 0;
}

static int __maybe_unused axp20x_pek_suspend(struct device *dev)
{
	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);

	/*
	 * As nested threaded IRQs are not automatically disabled during
	 * suspend, we must explicitly disable non-wakeup IRQs.
	 */
	if (device_may_wakeup(dev)) {
		enable_irq_wake(axp20x_pek->irq_dbf);
		enable_irq_wake(axp20x_pek->irq_dbr);
	} else {
		disable_irq(axp20x_pek->irq_dbf);
		disable_irq(axp20x_pek->irq_dbr);
	}

	return 0;
}

static int __maybe_unused axp20x_pek_resume(struct device *dev)
{
	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);

	if (device_may_wakeup(dev)) {
		disable_irq_wake(axp20x_pek->irq_dbf);
		disable_irq_wake(axp20x_pek->irq_dbr);
	} else {
		enable_irq(axp20x_pek->irq_dbf);
		enable_irq(axp20x_pek->irq_dbr);
	}

	return 0;
}

static int __maybe_unused axp20x_pek_resume_noirq(struct device *dev)
{
	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);

	if (axp20x_pek->axp20x->variant != AXP288_ID)
		return 0;

	/*
	 * Clear interrupts from button presses during suspend, to avoid
	 * a wakeup power-button press getting reported to userspace.
	 */
	regmap_write(axp20x_pek->axp20x->regmap,
		     AXP20X_IRQ1_STATE + AXP288_IRQ_POKN / 8,
		     BIT(AXP288_IRQ_POKN % 8));

	return 0;
}

static const struct dev_pm_ops axp20x_pek_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(axp20x_pek_suspend, axp20x_pek_resume)
#ifdef CONFIG_PM_SLEEP
	.resume_noirq = axp20x_pek_resume_noirq,
#endif
};

static const struct platform_device_id axp_pek_id_match[] = {
	{
		.name = "axp20x-pek",
		.driver_data = (kernel_ulong_t)&axp20x_info,
	},
	{
		.name = "axp221-pek",
		.driver_data = (kernel_ulong_t)&axp221_info,
	},
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, axp_pek_id_match);

static struct platform_driver axp20x_pek_driver = {
	.probe		= axp20x_pek_probe,
	.id_table	= axp_pek_id_match,
	.driver		= {
		.name		= "axp20x-pek",
		.pm		= &axp20x_pek_pm_ops,
		.dev_groups	= axp20x_groups,
	},
};
module_platform_driver(axp20x_pek_driver);

MODULE_DESCRIPTION("axp20x Power Button");
MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
MODULE_LICENSE("GPL");