// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * LoCoMo keyboard driver for Linux-based ARM PDAs:
 *      - SHARP Zaurus Collie (SL-5500)
 *      - SHARP Zaurus Poodle (SL-5600)
 *
 * Copyright (c) 2005 John Lenz
 * Based on from xtkbd.c
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>

#include <asm/hardware/locomo.h>
#include <asm/irq.h>

MODULE_AUTHOR("John Lenz <lenz@cs.wisc.edu>");
MODULE_DESCRIPTION("LoCoMo keyboard driver");
MODULE_LICENSE("GPL");

#define LOCOMOKBD_NUMKEYS       128

#define KEY_ACTIVITY            KEY_F16
#define KEY_CONTACT             KEY_F18
#define KEY_CENTER              KEY_F15

static const unsigned char
locomokbd_keycode[LOCOMOKBD_NUMKEYS] = {
        0, KEY_ESC, KEY_ACTIVITY, 0, 0, 0, 0, 0, 0, 0,                          /* 0 - 9 */
        0, 0, 0, 0, 0, 0, 0, KEY_MENU, KEY_HOME, KEY_CONTACT,                   /* 10 - 19 */
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0,                                           /* 20 - 29 */
        0, 0, 0, KEY_CENTER, 0, KEY_MAIL, 0, 0, 0, 0,                           /* 30 - 39 */
        0, 0, 0, 0, 0, 0, 0, 0, 0, KEY_RIGHT,                                   /* 40 - 49 */
        KEY_UP, KEY_LEFT, 0, 0, KEY_P, 0, KEY_O, KEY_I, KEY_Y, KEY_T,           /* 50 - 59 */
        KEY_E, KEY_W, 0, 0, 0, 0, KEY_DOWN, KEY_ENTER, 0, 0,                    /* 60 - 69 */
        KEY_BACKSPACE, 0, KEY_L, KEY_U, KEY_H, KEY_R, KEY_D, KEY_Q, 0, 0,       /* 70 - 79 */
        0, 0, 0, 0, 0, 0, KEY_ENTER, KEY_RIGHTSHIFT, KEY_K, KEY_J,              /* 80 - 89 */
        KEY_G, KEY_F, KEY_X, KEY_S, 0, 0, 0, 0, 0, 0,                           /* 90 - 99 */
        0, 0, KEY_DOT, 0, KEY_COMMA, KEY_N, KEY_B, KEY_C, KEY_Z, KEY_A,         /* 100 - 109 */
        KEY_LEFTSHIFT, KEY_TAB, KEY_LEFTCTRL, 0, 0, 0, 0, 0, 0, 0,              /* 110 - 119 */
        KEY_M, KEY_SPACE, KEY_V, KEY_APOSTROPHE, KEY_SLASH, 0, 0, 0             /* 120 - 128 */
};

#define KB_ROWS                 16
#define KB_COLS                 8
#define KB_ROWMASK(r)           (1 << (r))
#define SCANCODE(c,r)           ( ((c)<<4) + (r) + 1 )

#define KB_DELAY                8
#define SCAN_INTERVAL           (HZ/10)

struct locomokbd {
        unsigned char keycode[LOCOMOKBD_NUMKEYS];
        struct input_dev *input;
        char phys[32];

        unsigned long base;
        spinlock_t lock;

        struct timer_list timer;
        unsigned long suspend_jiffies;
        unsigned int count_cancel;
};

/* helper functions for reading the keyboard matrix */
static inline void locomokbd_charge_all(unsigned long membase)
{
        locomo_writel(0x00FF, membase + LOCOMO_KSC);
}

static inline void locomokbd_activate_all(unsigned long membase)
{
        unsigned long r;

        locomo_writel(0, membase + LOCOMO_KSC);
        r = locomo_readl(membase + LOCOMO_KIC);
        r &= 0xFEFF;
        locomo_writel(r, membase + LOCOMO_KIC);
}

static inline void locomokbd_activate_col(unsigned long membase, int col)
{
        unsigned short nset;
        unsigned short nbset;

        nset = 0xFF & ~(1 << col);
        nbset = (nset << 8) + nset;
        locomo_writel(nbset, membase + LOCOMO_KSC);
}

static inline void locomokbd_reset_col(unsigned long membase, int col)
{
        unsigned short nbset;

        nbset = ((0xFF & ~(1 << col)) << 8) + 0xFF;
        locomo_writel(nbset, membase + LOCOMO_KSC);
}

/*
 * The LoCoMo keyboard only generates interrupts when a key is pressed.
 * So when a key is pressed, we enable a timer.  This timer scans the
 * keyboard, and this is how we detect when the key is released.
 */

/* Scan the hardware keyboard and push any changes up through the input layer */
static void locomokbd_scankeyboard(struct locomokbd *locomokbd)
{
        unsigned int row, col, rowd;
        unsigned int num_pressed;
        unsigned long membase = locomokbd->base;

        guard(spinlock_irqsave)(&locomokbd->lock);

        locomokbd_charge_all(membase);

        num_pressed = 0;
        for (col = 0; col < KB_COLS; col++) {

                locomokbd_activate_col(membase, col);
                udelay(KB_DELAY);

                rowd = ~locomo_readl(membase + LOCOMO_KIB);
                for (row = 0; row < KB_ROWS; row++) {
                        unsigned int scancode, pressed, key;

                        scancode = SCANCODE(col, row);
                        pressed = rowd & KB_ROWMASK(row);
                        key = locomokbd->keycode[scancode];

                        input_report_key(locomokbd->input, key, pressed);
                        if (likely(!pressed))
                                continue;

                        num_pressed++;

                        /* The "Cancel/ESC" key is labeled "On/Off" on
                         * Collie and Poodle and should suspend the device
                         * if it was pressed for more than a second. */
                        if (unlikely(key == KEY_ESC)) {
                                if (!time_after(jiffies,
                                        locomokbd->suspend_jiffies + HZ))
                                        continue;
                                if (locomokbd->count_cancel++
                                        != (HZ/SCAN_INTERVAL + 1))
                                        continue;
                                input_event(locomokbd->input, EV_PWR,
                                        KEY_SUSPEND, 1);
                                locomokbd->suspend_jiffies = jiffies;
                        } else
                                locomokbd->count_cancel = 0;
                }
                locomokbd_reset_col(membase, col);
        }
        locomokbd_activate_all(membase);

        input_sync(locomokbd->input);

        /* if any keys are pressed, enable the timer */
        if (num_pressed)
                mod_timer(&locomokbd->timer, jiffies + SCAN_INTERVAL);
        else
                locomokbd->count_cancel = 0;
}

/*
 * LoCoMo keyboard interrupt handler.
 */
static irqreturn_t locomokbd_interrupt(int irq, void *dev_id)
{
        struct locomokbd *locomokbd = dev_id;
        u16 r;

        r = locomo_readl(locomokbd->base + LOCOMO_KIC);
        if ((r & 0x0001) == 0)
                return IRQ_HANDLED;

        locomo_writel(r & ~0x0100, locomokbd->base + LOCOMO_KIC); /* Ack */

        /** wait chattering delay **/
        udelay(100);

        locomokbd_scankeyboard(locomokbd);
        return IRQ_HANDLED;
}

/*
 * LoCoMo timer checking for released keys
 */
static void locomokbd_timer_callback(struct timer_list *t)
{
        struct locomokbd *locomokbd = timer_container_of(locomokbd, t, timer);

        locomokbd_scankeyboard(locomokbd);
}

static int locomokbd_open(struct input_dev *dev)
{
        struct locomokbd *locomokbd = input_get_drvdata(dev);
        u16 r;
        
        r = locomo_readl(locomokbd->base + LOCOMO_KIC) | 0x0010;
        locomo_writel(r, locomokbd->base + LOCOMO_KIC);
        return 0;
}

static void locomokbd_close(struct input_dev *dev)
{
        struct locomokbd *locomokbd = input_get_drvdata(dev);
        u16 r;
        
        r = locomo_readl(locomokbd->base + LOCOMO_KIC) & ~0x0010;
        locomo_writel(r, locomokbd->base + LOCOMO_KIC);
}

static int locomokbd_probe(struct locomo_dev *dev)
{
        struct locomokbd *locomokbd;
        struct input_dev *input_dev;
        int i, err;

        locomokbd = kzalloc_obj(*locomokbd);
        input_dev = input_allocate_device();
        if (!locomokbd || !input_dev) {
                err = -ENOMEM;
                goto err_free_mem;
        }

        /* try and claim memory region */
        if (!request_mem_region((unsigned long) dev->mapbase,
                                dev->length,
                                LOCOMO_DRIVER_NAME(dev))) {
                err = -EBUSY;
                printk(KERN_ERR "locomokbd: Can't acquire access to io memory for keyboard\n");
                goto err_free_mem;
        }

        locomo_set_drvdata(dev, locomokbd);

        locomokbd->base = (unsigned long) dev->mapbase;

        spin_lock_init(&locomokbd->lock);

        timer_setup(&locomokbd->timer, locomokbd_timer_callback, 0);

        locomokbd->suspend_jiffies = jiffies;

        locomokbd->input = input_dev;
        strcpy(locomokbd->phys, "locomokbd/input0");

        input_dev->name = "LoCoMo keyboard";
        input_dev->phys = locomokbd->phys;
        input_dev->id.bustype = BUS_HOST;
        input_dev->id.vendor = 0x0001;
        input_dev->id.product = 0x0001;
        input_dev->id.version = 0x0100;
        input_dev->open = locomokbd_open;
        input_dev->close = locomokbd_close;
        input_dev->dev.parent = &dev->dev;

        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP) |
                                BIT_MASK(EV_PWR);
        input_dev->keycode = locomokbd->keycode;
        input_dev->keycodesize = sizeof(locomokbd_keycode[0]);
        input_dev->keycodemax = ARRAY_SIZE(locomokbd_keycode);

        input_set_drvdata(input_dev, locomokbd);

        memcpy(locomokbd->keycode, locomokbd_keycode, sizeof(locomokbd->keycode));
        for (i = 0; i < LOCOMOKBD_NUMKEYS; i++)
                set_bit(locomokbd->keycode[i], input_dev->keybit);
        clear_bit(0, input_dev->keybit);

        /* attempt to get the interrupt */
        err = request_irq(dev->irq[0], locomokbd_interrupt, 0, "locomokbd", locomokbd);
        if (err) {
                printk(KERN_ERR "locomokbd: Can't get irq for keyboard\n");
                goto err_release_region;
        }

        err = input_register_device(locomokbd->input);
        if (err)
                goto err_free_irq;

        return 0;

 err_free_irq:
        free_irq(dev->irq[0], locomokbd);
 err_release_region:
        release_mem_region((unsigned long) dev->mapbase, dev->length);
        locomo_set_drvdata(dev, NULL);
 err_free_mem:
        input_free_device(input_dev);
        kfree(locomokbd);

        return err;
}

static void locomokbd_remove(struct locomo_dev *dev)
{
        struct locomokbd *locomokbd = locomo_get_drvdata(dev);

        free_irq(dev->irq[0], locomokbd);

        timer_shutdown_sync(&locomokbd->timer);

        input_unregister_device(locomokbd->input);
        locomo_set_drvdata(dev, NULL);

        release_mem_region((unsigned long) dev->mapbase, dev->length);

        kfree(locomokbd);
}

static struct locomo_driver keyboard_driver = {
        .drv = {
                .name = "locomokbd"
        },
        .devid  = LOCOMO_DEVID_KEYBOARD,
        .probe  = locomokbd_probe,
        .remove = locomokbd_remove,
};

static int __init locomokbd_init(void)
{
        return locomo_driver_register(&keyboard_driver);
}

static void __exit locomokbd_exit(void)
{
        locomo_driver_unregister(&keyboard_driver);
}

module_init(locomokbd_init);
module_exit(locomokbd_exit);