// SPDX-License-Identifier: GPL-2.0-or-later
/*
    i2c Support for the Apple `Hydra' Mac I/O

    Copyright (c) 1999-2004 Geert Uytterhoeven <geert@linux-m68k.org>

    Based on i2c Support for Via Technologies 82C586B South Bridge
    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>

*/

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/types.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/io.h>
#include <asm/hydra.h>


#define HYDRA_CPD_PD0   0x00000001      /* CachePD lines */
#define HYDRA_CPD_PD1   0x00000002
#define HYDRA_CPD_PD2   0x00000004
#define HYDRA_CPD_PD3   0x00000008

#define HYDRA_SCLK      HYDRA_CPD_PD0
#define HYDRA_SDAT      HYDRA_CPD_PD1
#define HYDRA_SCLK_OE   0x00000010
#define HYDRA_SDAT_OE   0x00000020

static inline void pdregw(void *data, u32 val)
{
        struct Hydra *hydra = (struct Hydra *)data;
        writel(val, &hydra->CachePD);
}

static inline u32 pdregr(void *data)
{
        struct Hydra *hydra = (struct Hydra *)data;
        return readl(&hydra->CachePD);
}

static void hydra_bit_setscl(void *data, int state)
{
        u32 val = pdregr(data);
        if (state)
                val &= ~HYDRA_SCLK_OE;
        else {
                val &= ~HYDRA_SCLK;
                val |= HYDRA_SCLK_OE;
        }
        pdregw(data, val);
}

static void hydra_bit_setsda(void *data, int state)
{
        u32 val = pdregr(data);
        if (state)
                val &= ~HYDRA_SDAT_OE;
        else {
                val &= ~HYDRA_SDAT;
                val |= HYDRA_SDAT_OE;
        }
        pdregw(data, val);
}

static int hydra_bit_getscl(void *data)
{
        return (pdregr(data) & HYDRA_SCLK) != 0;
}

static int hydra_bit_getsda(void *data)
{
        return (pdregr(data) & HYDRA_SDAT) != 0;
}

/* ------------------------------------------------------------------------ */

static struct i2c_algo_bit_data hydra_bit_data = {
        .setsda         = hydra_bit_setsda,
        .setscl         = hydra_bit_setscl,
        .getsda         = hydra_bit_getsda,
        .getscl         = hydra_bit_getscl,
        .udelay         = 5,
        .timeout        = HZ
};

static struct i2c_adapter hydra_adap = {
        .owner          = THIS_MODULE,
        .name           = "Hydra i2c",
        .algo_data      = &hydra_bit_data,
};

static const struct pci_device_id hydra_ids[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_APPLE, PCI_DEVICE_ID_APPLE_HYDRA) },
        { 0, }
};

MODULE_DEVICE_TABLE (pci, hydra_ids);

static int hydra_probe(struct pci_dev *dev,
                                 const struct pci_device_id *id)
{
        unsigned long base = pci_resource_start(dev, 0);
        int res;

        if (!request_mem_region(base+offsetof(struct Hydra, CachePD), 4,
                                hydra_adap.name))
                return -EBUSY;

        hydra_bit_data.data = pci_ioremap_bar(dev, 0);
        if (hydra_bit_data.data == NULL) {
                release_mem_region(base+offsetof(struct Hydra, CachePD), 4);
                return -ENODEV;
        }

        pdregw(hydra_bit_data.data, 0);         /* clear SCLK_OE and SDAT_OE */
        hydra_adap.dev.parent = &dev->dev;
        res = i2c_bit_add_bus(&hydra_adap);
        if (res < 0) {
                iounmap(hydra_bit_data.data);
                release_mem_region(base+offsetof(struct Hydra, CachePD), 4);
                return res;
        }
        return 0;
}

static void hydra_remove(struct pci_dev *dev)
{
        pdregw(hydra_bit_data.data, 0);         /* clear SCLK_OE and SDAT_OE */
        i2c_del_adapter(&hydra_adap);
        iounmap(hydra_bit_data.data);
        release_mem_region(pci_resource_start(dev, 0)+
                           offsetof(struct Hydra, CachePD), 4);
}


static struct pci_driver hydra_driver = {
        .name           = "hydra_smbus",
        .id_table       = hydra_ids,
        .probe          = hydra_probe,
        .remove         = hydra_remove,
};

module_pci_driver(hydra_driver);

MODULE_AUTHOR("Geert Uytterhoeven <geert@linux-m68k.org>");
MODULE_DESCRIPTION("i2c for Apple Hydra Mac I/O");
MODULE_LICENSE("GPL");