// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OMAP4 Keypad Driver
 *
 * Copyright (C) 2010 Texas Instruments
 *
 * Author: Abraham Arce <x0066660@ti.com>
 * Initial Code: Syed Rafiuddin <rafiuddin.syed@ti.com>
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/input.h>
#include <linux/input/matrix_keypad.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/pm_wakeirq.h>

/* OMAP4 registers */
#define OMAP4_KBD_REVISION              0x00
#define OMAP4_KBD_SYSCONFIG             0x10
#define OMAP4_KBD_SYSSTATUS             0x14
#define OMAP4_KBD_IRQSTATUS             0x18
#define OMAP4_KBD_IRQENABLE             0x1C
#define OMAP4_KBD_WAKEUPENABLE          0x20
#define OMAP4_KBD_PENDING               0x24
#define OMAP4_KBD_CTRL                  0x28
#define OMAP4_KBD_DEBOUNCINGTIME        0x2C
#define OMAP4_KBD_LONGKEYTIME           0x30
#define OMAP4_KBD_TIMEOUT               0x34
#define OMAP4_KBD_STATEMACHINE          0x38
#define OMAP4_KBD_ROWINPUTS             0x3C
#define OMAP4_KBD_COLUMNOUTPUTS         0x40
#define OMAP4_KBD_FULLCODE31_0          0x44
#define OMAP4_KBD_FULLCODE63_32         0x48

/* OMAP4 bit definitions */
#define OMAP4_DEF_IRQENABLE_EVENTEN     BIT(0)
#define OMAP4_DEF_IRQENABLE_LONGKEY     BIT(1)
#define OMAP4_DEF_WUP_EVENT_ENA         BIT(0)
#define OMAP4_DEF_WUP_LONG_KEY_ENA      BIT(1)
#define OMAP4_DEF_CTRL_NOSOFTMODE       BIT(1)
#define OMAP4_DEF_CTRL_PTV_SHIFT        2

/* OMAP4 values */
#define OMAP4_VAL_IRQDISABLE            0x0

/*
 * Errata i689: If a key is released for a time shorter than debounce time,
 * the keyboard will idle and never detect the key release. The workaround
 * is to use at least a 12ms debounce time. See omap5432 TRM chapter
 * "26.4.6.2 Keyboard Controller Timer" for more information.
 */
#define OMAP4_KEYPAD_PTV_DIV_128        0x6
#define OMAP4_KEYPAD_DEBOUNCINGTIME_MS(dbms, ptv)     \
        ((((dbms) * 1000) / ((1 << ((ptv) + 1)) * (1000000 / 32768))) - 1)
#define OMAP4_VAL_DEBOUNCINGTIME_16MS                                   \
        OMAP4_KEYPAD_DEBOUNCINGTIME_MS(16, OMAP4_KEYPAD_PTV_DIV_128)
#define OMAP4_KEYPAD_AUTOIDLE_MS        50      /* Approximate measured time */
#define OMAP4_KEYPAD_IDLE_CHECK_MS      (OMAP4_KEYPAD_AUTOIDLE_MS / 2)

enum {
        KBD_REVISION_OMAP4 = 0,
        KBD_REVISION_OMAP5,
};

struct omap4_keypad {
        struct input_dev *input;

        void __iomem *base;
        unsigned int irq;
        struct mutex lock;              /* for key scan */

        unsigned int rows;
        unsigned int cols;
        u32 reg_offset;
        u32 irqreg_offset;
        unsigned int row_shift;
        bool no_autorepeat;
        u64 keys;
        unsigned short *keymap;
        struct clk *fck;
};

static int kbd_readl(struct omap4_keypad *keypad_data, u32 offset)
{
        return __raw_readl(keypad_data->base +
                                keypad_data->reg_offset + offset);
}

static void kbd_writel(struct omap4_keypad *keypad_data, u32 offset, u32 value)
{
        __raw_writel(value,
                     keypad_data->base + keypad_data->reg_offset + offset);
}

static int kbd_read_irqreg(struct omap4_keypad *keypad_data, u32 offset)
{
        return __raw_readl(keypad_data->base +
                                keypad_data->irqreg_offset + offset);
}

static void kbd_write_irqreg(struct omap4_keypad *keypad_data,
                             u32 offset, u32 value)
{
        __raw_writel(value,
                     keypad_data->base + keypad_data->irqreg_offset + offset);
}

static int omap4_keypad_report_keys(struct omap4_keypad *keypad_data,
                                    u64 keys, bool down)
{
        struct input_dev *input_dev = keypad_data->input;
        unsigned int col, row, code;
        DECLARE_BITMAP(mask, 64);
        unsigned long bit;
        int events = 0;

        bitmap_from_u64(mask, keys);

        for_each_set_bit(bit, mask, keypad_data->rows * BITS_PER_BYTE) {
                row = bit / BITS_PER_BYTE;
                col = bit % BITS_PER_BYTE;
                code = MATRIX_SCAN_CODE(row, col, keypad_data->row_shift);

                input_event(input_dev, EV_MSC, MSC_SCAN, code);
                input_report_key(input_dev, keypad_data->keymap[code], down);

                events++;
        }

        if (events)
                input_sync(input_dev);

        return events;
}

static void omap4_keypad_scan_keys(struct omap4_keypad *keypad_data, u64 keys)
{
        u64 changed;

        guard(mutex)(&keypad_data->lock);

        changed = keys ^ keypad_data->keys;

        /*
         * Report key up events separately and first. This matters in case we
         * lost key-up interrupt and just now catching up.
         */
        omap4_keypad_report_keys(keypad_data, changed & ~keys, false);

        /* Report key down events */
        omap4_keypad_report_keys(keypad_data, changed & keys, true);

        keypad_data->keys = keys;
}

/* Interrupt handlers */
static irqreturn_t omap4_keypad_irq_handler(int irq, void *dev_id)
{
        struct omap4_keypad *keypad_data = dev_id;

        if (kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS))
                return IRQ_WAKE_THREAD;

        return IRQ_NONE;
}

static irqreturn_t omap4_keypad_irq_thread_fn(int irq, void *dev_id)
{
        struct omap4_keypad *keypad_data = dev_id;
        struct device *dev = keypad_data->input->dev.parent;
        u32 low, high;
        int error;
        u64 keys;

        error = pm_runtime_resume_and_get(dev);
        if (error)
                return IRQ_NONE;

        low = kbd_readl(keypad_data, OMAP4_KBD_FULLCODE31_0);
        high = kbd_readl(keypad_data, OMAP4_KBD_FULLCODE63_32);
        keys = low | (u64)high << 32;

        omap4_keypad_scan_keys(keypad_data, keys);

        /* clear pending interrupts */
        kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
                         kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));

        pm_runtime_put_autosuspend(dev);

        return IRQ_HANDLED;
}

static int omap4_keypad_open(struct input_dev *input)
{
        struct omap4_keypad *keypad_data = input_get_drvdata(input);
        struct device *dev = input->dev.parent;
        int error;

        error = pm_runtime_resume_and_get(dev);
        if (error)
                return error;

        error = clk_prepare_enable(keypad_data->fck);
        if (error)
                goto out;

        disable_irq(keypad_data->irq);

        kbd_writel(keypad_data, OMAP4_KBD_CTRL,
                        OMAP4_DEF_CTRL_NOSOFTMODE |
                        (OMAP4_KEYPAD_PTV_DIV_128 << OMAP4_DEF_CTRL_PTV_SHIFT));
        kbd_writel(keypad_data, OMAP4_KBD_DEBOUNCINGTIME,
                        OMAP4_VAL_DEBOUNCINGTIME_16MS);
        /* clear pending interrupts */
        kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
                         kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));
        kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
                        OMAP4_DEF_IRQENABLE_EVENTEN);
        kbd_writel(keypad_data, OMAP4_KBD_WAKEUPENABLE,
                        OMAP4_DEF_WUP_EVENT_ENA);

        enable_irq(keypad_data->irq);

out:
        pm_runtime_put_autosuspend(dev);

        return error;
}

static void omap4_keypad_stop(struct omap4_keypad *keypad_data)
{
        /* Disable interrupts and wake-up events */
        kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
                         OMAP4_VAL_IRQDISABLE);
        kbd_writel(keypad_data, OMAP4_KBD_WAKEUPENABLE, 0);

        /* clear pending interrupts */
        kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
                         kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));
}

static void omap4_keypad_close(struct input_dev *input)
{
        struct omap4_keypad *keypad_data = input_get_drvdata(input);
        struct device *dev = input->dev.parent;
        int error;

        error = pm_runtime_resume_and_get(dev);
        if (error)
                dev_err(dev, "%s: pm_runtime_resume_and_get() failed: %d\n",
                        __func__, error);

        disable_irq(keypad_data->irq);
        omap4_keypad_stop(keypad_data);
        enable_irq(keypad_data->irq);
        clk_disable_unprepare(keypad_data->fck);

        pm_runtime_put_autosuspend(dev);
}

static int omap4_keypad_parse_dt(struct device *dev,
                                 struct omap4_keypad *keypad_data)
{
        struct device_node *np = dev->of_node;
        int err;

        err = matrix_keypad_parse_properties(dev, &keypad_data->rows,
                                             &keypad_data->cols);
        if (err)
                return err;

        keypad_data->no_autorepeat = of_property_read_bool(np, "linux,input-no-autorepeat");

        return 0;
}

static int omap4_keypad_check_revision(struct device *dev,
                                       struct omap4_keypad *keypad_data)
{
        unsigned int rev;

        rev = __raw_readl(keypad_data->base + OMAP4_KBD_REVISION);
        rev &= 0x03 << 30;
        rev >>= 30;
        switch (rev) {
        case KBD_REVISION_OMAP4:
                keypad_data->reg_offset = 0x00;
                keypad_data->irqreg_offset = 0x00;
                break;
        case KBD_REVISION_OMAP5:
                keypad_data->reg_offset = 0x10;
                keypad_data->irqreg_offset = 0x0c;
                break;
        default:
                dev_err(dev, "Keypad reports unsupported revision %d", rev);
                return -EINVAL;
        }

        return 0;
}

/*
 * Errata ID i689 "1.32 Keyboard Key Up Event Can Be Missed".
 * Interrupt may not happen for key-up events. We must clear stuck
 * key-up events after the keyboard hardware has auto-idled.
 */
static int omap4_keypad_runtime_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct omap4_keypad *keypad_data = platform_get_drvdata(pdev);
        u32 active;

        active = kbd_readl(keypad_data, OMAP4_KBD_STATEMACHINE);
        if (active) {
                pm_runtime_mark_last_busy(dev);
                return -EBUSY;
        }

        omap4_keypad_scan_keys(keypad_data, 0);

        return 0;
}

static const struct dev_pm_ops omap4_keypad_pm_ops = {
        RUNTIME_PM_OPS(omap4_keypad_runtime_suspend, NULL, NULL)
};

static void omap4_disable_pm(void *d)
{
        pm_runtime_dont_use_autosuspend(d);
        pm_runtime_disable(d);
}

static int omap4_keypad_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct omap4_keypad *keypad_data;
        struct input_dev *input_dev;
        unsigned int max_keys;
        int irq;
        int error;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        keypad_data = devm_kzalloc(dev, sizeof(*keypad_data), GFP_KERNEL);
        if (!keypad_data) {
                dev_err(dev, "keypad_data memory allocation failed\n");
                return -ENOMEM;
        }

        keypad_data->irq = irq;
        keypad_data->fck = devm_clk_get(&pdev->dev, "fck");
        if (IS_ERR(keypad_data->fck))
                return dev_err_probe(&pdev->dev, PTR_ERR(keypad_data->fck),
                                     "unable to get fck");

        mutex_init(&keypad_data->lock);
        platform_set_drvdata(pdev, keypad_data);

        error = omap4_keypad_parse_dt(dev, keypad_data);
        if (error)
                return error;

        keypad_data->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(keypad_data->base))
                return PTR_ERR(keypad_data->base);

        pm_runtime_use_autosuspend(dev);
        pm_runtime_set_autosuspend_delay(dev, OMAP4_KEYPAD_IDLE_CHECK_MS);
        pm_runtime_enable(dev);

        error = devm_add_action_or_reset(dev, omap4_disable_pm, dev);
        if (error) {
                dev_err(dev, "unable to register cleanup action\n");
                return error;
        }

        /*
         * Enable clocks for the keypad module so that we can read
         * revision register.
         */
        error = pm_runtime_resume_and_get(dev);
        if (error) {
                dev_err(dev, "pm_runtime_resume_and_get() failed\n");
                return error;
        }

        error = omap4_keypad_check_revision(dev, keypad_data);
        if (!error) {
                /* Ensure device does not raise interrupts */
                omap4_keypad_stop(keypad_data);
        }

        pm_runtime_put_autosuspend(dev);
        if (error)
                return error;

        /* input device allocation */
        keypad_data->input = input_dev = devm_input_allocate_device(dev);
        if (!input_dev)
                return -ENOMEM;

        input_dev->name = pdev->name;
        input_dev->id.bustype = BUS_HOST;
        input_dev->id.vendor = 0x0001;
        input_dev->id.product = 0x0001;
        input_dev->id.version = 0x0001;

        input_dev->open = omap4_keypad_open;
        input_dev->close = omap4_keypad_close;

        input_set_capability(input_dev, EV_MSC, MSC_SCAN);
        if (!keypad_data->no_autorepeat)
                __set_bit(EV_REP, input_dev->evbit);

        input_set_drvdata(input_dev, keypad_data);

        keypad_data->row_shift = get_count_order(keypad_data->cols);
        max_keys = keypad_data->rows << keypad_data->row_shift;
        keypad_data->keymap = devm_kcalloc(dev,
                                           max_keys,
                                           sizeof(keypad_data->keymap[0]),
                                           GFP_KERNEL);
        if (!keypad_data->keymap) {
                dev_err(dev, "Not enough memory for keymap\n");
                return -ENOMEM;
        }

        error = matrix_keypad_build_keymap(NULL, NULL,
                                           keypad_data->rows, keypad_data->cols,
                                           keypad_data->keymap, input_dev);
        if (error) {
                dev_err(dev, "failed to build keymap\n");
                return error;
        }

        error = devm_request_threaded_irq(dev, keypad_data->irq,
                                          omap4_keypad_irq_handler,
                                          omap4_keypad_irq_thread_fn,
                                          IRQF_ONESHOT,
                                          "omap4-keypad", keypad_data);
        if (error) {
                dev_err(dev, "failed to register interrupt\n");
                return error;
        }

        error = input_register_device(keypad_data->input);
        if (error) {
                dev_err(dev, "failed to register input device\n");
                return error;
        }

        device_init_wakeup(dev, true);
        error = dev_pm_set_wake_irq(dev, keypad_data->irq);
        if (error)
                dev_warn(dev, "failed to set up wakeup irq: %d\n", error);

        return 0;
}

static void omap4_keypad_remove(struct platform_device *pdev)
{
        dev_pm_clear_wake_irq(&pdev->dev);
}

static const struct of_device_id omap_keypad_dt_match[] = {
        { .compatible = "ti,omap4-keypad" },
        {},
};
MODULE_DEVICE_TABLE(of, omap_keypad_dt_match);

static struct platform_driver omap4_keypad_driver = {
        .probe          = omap4_keypad_probe,
        .remove         = omap4_keypad_remove,
        .driver         = {
                .name   = "omap4-keypad",
                .of_match_table = omap_keypad_dt_match,
                .pm = pm_ptr(&omap4_keypad_pm_ops),
        },
};
module_platform_driver(omap4_keypad_driver);

MODULE_AUTHOR("Texas Instruments");
MODULE_DESCRIPTION("OMAP4 Keypad Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:omap4-keypad");