/*
 * 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 input_dev *idev = pwr;
        struct axp20x_pek *axp20x_pek = input_get_drvdata(idev);

        /*
         * 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 axp20x_dev *axp20x = axp20x_pek->axp20x;
        struct input_dev *idev;
        int error;

        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->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->regmap_irqc,
                                                  axp20x_pek->irq_dbf);

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

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

        device_init_wakeup(&pdev->dev, true);

        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);

        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;

        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");