// SPDX-License-Identifier: GPL-2.0
/* auxio.c: Probing for the Sparc AUXIO register at boot time.
 *
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 *
 * Refactoring for unified NCR/PCIO support 2002 Eric Brower (ebrower@usa.net)
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/of.h>
#include <linux/platform_device.h>

#include <asm/prom.h>
#include <asm/io.h>
#include <asm/auxio.h>

void __iomem *auxio_register = NULL;
EXPORT_SYMBOL(auxio_register);

enum auxio_type {
        AUXIO_TYPE_NODEV,
        AUXIO_TYPE_SBUS,
        AUXIO_TYPE_EBUS
};

static enum auxio_type auxio_devtype = AUXIO_TYPE_NODEV;
static DEFINE_SPINLOCK(auxio_lock);

static void __auxio_rmw(u8 bits_on, u8 bits_off, int ebus)
{
        if (auxio_register) {
                unsigned long flags;
                u8 regval, newval;

                spin_lock_irqsave(&auxio_lock, flags);

                regval = (ebus ?
                          (u8) readl(auxio_register) :
                          sbus_readb(auxio_register));
                newval =  regval | bits_on;
                newval &= ~bits_off;
                if (!ebus)
                        newval &= ~AUXIO_AUX1_MASK;
                if (ebus)
                        writel((u32) newval, auxio_register);
                else
                        sbus_writeb(newval, auxio_register);
                
                spin_unlock_irqrestore(&auxio_lock, flags);
        }
}

static void __auxio_set_bit(u8 bit, int on, int ebus)
{
        u8 bits_on = (ebus ? AUXIO_PCIO_LED : AUXIO_AUX1_LED);
        u8 bits_off = 0;

        if (!on) {
                u8 tmp = bits_off;
                bits_off = bits_on;
                bits_on = tmp;
        }
        __auxio_rmw(bits_on, bits_off, ebus);
}

void auxio_set_led(int on)
{
        int ebus = auxio_devtype == AUXIO_TYPE_EBUS;
        u8 bit;

        bit = (ebus ? AUXIO_PCIO_LED : AUXIO_AUX1_LED);
        __auxio_set_bit(bit, on, ebus);
}
EXPORT_SYMBOL(auxio_set_led);

static void __auxio_sbus_set_lte(int on)
{
        __auxio_set_bit(AUXIO_AUX1_LTE, on, 0);
}

void auxio_set_lte(int on)
{
        switch(auxio_devtype) {
        case AUXIO_TYPE_SBUS:
                __auxio_sbus_set_lte(on);
                break;
        case AUXIO_TYPE_EBUS:
        default:
                break;
        }
}
EXPORT_SYMBOL(auxio_set_lte);

static const struct of_device_id auxio_match[] = {
        {
                .name = "auxio",
        },
        {},
};

MODULE_DEVICE_TABLE(of, auxio_match);

static int auxio_probe(struct platform_device *dev)
{
        struct device_node *dp = dev->dev.of_node;
        unsigned long size;

        if (of_node_name_eq(dp->parent, "ebus")) {
                auxio_devtype = AUXIO_TYPE_EBUS;
                size = sizeof(u32);
        } else if (of_node_name_eq(dp->parent, "sbus")) {
                auxio_devtype = AUXIO_TYPE_SBUS;
                size = 1;
        } else {
                printk("auxio: Unknown parent bus type [%pOFn]\n",
                       dp->parent);
                return -ENODEV;
        }
        auxio_register = of_ioremap(&dev->resource[0], 0, size, "auxio");
        if (!auxio_register)
                return -ENODEV;

        printk(KERN_INFO "AUXIO: Found device at %pOF\n", dp);

        if (auxio_devtype == AUXIO_TYPE_EBUS)
                auxio_set_led(AUXIO_LED_ON);

        return 0;
}

static struct platform_driver auxio_driver = {
        .probe          = auxio_probe,
        .driver = {
                .name = "auxio",
                .of_match_table = auxio_match,
        },
};

static int __init auxio_init(void)
{
        return platform_driver_register(&auxio_driver);
}

/* Must be after subsys_initcall() so that busses are probed.  Must
 * be before device_initcall() because things like the floppy driver
 * need to use the AUXIO register.
 */
fs_initcall(auxio_init);