// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  linux/drivers/input/serio/ambakmi.c
 *
 *  Copyright (C) 2000-2003 Deep Blue Solutions Ltd.
 *  Copyright (C) 2002 Russell King.
 */
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/amba/bus.h>
#include <linux/amba/kmi.h>
#include <linux/clk.h>

#include <asm/io.h>
#include <asm/irq.h>

#define KMI_BASE        (kmi->base)

struct amba_kmi_port {
        struct serio            *io;
        struct clk              *clk;
        void __iomem            *base;
        unsigned int            irq;
        unsigned int            divisor;
        unsigned int            open;
};

static irqreturn_t amba_kmi_int(int irq, void *dev_id)
{
        struct amba_kmi_port *kmi = dev_id;
        unsigned int status = readb(KMIIR);
        int handled = IRQ_NONE;

        while (status & KMIIR_RXINTR) {
                serio_interrupt(kmi->io, readb(KMIDATA), 0);
                status = readb(KMIIR);
                handled = IRQ_HANDLED;
        }

        return handled;
}

static int amba_kmi_write(struct serio *io, unsigned char val)
{
        struct amba_kmi_port *kmi = io->port_data;
        unsigned int timeleft = 10000; /* timeout in 100ms */

        while ((readb(KMISTAT) & KMISTAT_TXEMPTY) == 0 && --timeleft)
                udelay(10);

        if (timeleft)
                writeb(val, KMIDATA);

        return timeleft ? 0 : SERIO_TIMEOUT;
}

static int amba_kmi_open(struct serio *io)
{
        struct amba_kmi_port *kmi = io->port_data;
        unsigned int divisor;
        int ret;

        ret = clk_prepare_enable(kmi->clk);
        if (ret)
                goto out;

        divisor = clk_get_rate(kmi->clk) / 8000000 - 1;
        writeb(divisor, KMICLKDIV);
        writeb(KMICR_EN, KMICR);

        ret = request_irq(kmi->irq, amba_kmi_int, IRQF_SHARED, "kmi-pl050",
                          kmi);
        if (ret) {
                printk(KERN_ERR "kmi: failed to claim IRQ%d\n", kmi->irq);
                writeb(0, KMICR);
                goto clk_disable;
        }

        writeb(KMICR_EN | KMICR_RXINTREN, KMICR);

        return 0;

 clk_disable:
        clk_disable_unprepare(kmi->clk);
 out:
        return ret;
}

static void amba_kmi_close(struct serio *io)
{
        struct amba_kmi_port *kmi = io->port_data;

        writeb(0, KMICR);

        free_irq(kmi->irq, kmi);
        clk_disable_unprepare(kmi->clk);
}

static int amba_kmi_probe(struct amba_device *dev,
        const struct amba_id *id)
{
        struct amba_kmi_port *kmi;
        struct serio *io;
        int ret;

        ret = amba_request_regions(dev, NULL);
        if (ret)
                return ret;

        kmi = kzalloc_obj(*kmi);
        io = kzalloc_obj(*io);
        if (!kmi || !io) {
                ret = -ENOMEM;
                goto out;
        }


        io->id.type     = SERIO_8042;
        io->write       = amba_kmi_write;
        io->open        = amba_kmi_open;
        io->close       = amba_kmi_close;
        strscpy(io->name, dev_name(&dev->dev), sizeof(io->name));
        strscpy(io->phys, dev_name(&dev->dev), sizeof(io->phys));
        io->port_data   = kmi;
        io->dev.parent  = &dev->dev;

        kmi->io         = io;
        kmi->base       = ioremap(dev->res.start, resource_size(&dev->res));
        if (!kmi->base) {
                ret = -ENOMEM;
                goto out;
        }

        kmi->clk = clk_get(&dev->dev, "KMIREFCLK");
        if (IS_ERR(kmi->clk)) {
                ret = PTR_ERR(kmi->clk);
                goto unmap;
        }

        kmi->irq = dev->irq[0];
        amba_set_drvdata(dev, kmi);

        serio_register_port(kmi->io);
        return 0;

 unmap:
        iounmap(kmi->base);
 out:
        kfree(kmi);
        kfree(io);
        amba_release_regions(dev);
        return ret;
}

static void amba_kmi_remove(struct amba_device *dev)
{
        struct amba_kmi_port *kmi = amba_get_drvdata(dev);

        serio_unregister_port(kmi->io);
        clk_put(kmi->clk);
        iounmap(kmi->base);
        kfree(kmi);
        amba_release_regions(dev);
}

static int amba_kmi_resume(struct device *dev)
{
        struct amba_kmi_port *kmi = dev_get_drvdata(dev);

        /* kick the serio layer to rescan this port */
        serio_reconnect(kmi->io);

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(amba_kmi_dev_pm_ops, NULL, amba_kmi_resume);

static const struct amba_id amba_kmi_idtable[] = {
        {
                .id     = 0x00041050,
                .mask   = 0x000fffff,
        },
        { 0, 0 }
};

MODULE_DEVICE_TABLE(amba, amba_kmi_idtable);

static struct amba_driver ambakmi_driver = {
        .drv            = {
                .name   = "kmi-pl050",
                .pm     = pm_sleep_ptr(&amba_kmi_dev_pm_ops),
        },
        .id_table       = amba_kmi_idtable,
        .probe          = amba_kmi_probe,
        .remove         = amba_kmi_remove,
};

module_amba_driver(ambakmi_driver);

MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
MODULE_DESCRIPTION("AMBA KMI controller driver");
MODULE_LICENSE("GPL");