// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 1998-2009 VIA Technologies, Inc. All Rights Reserved.
 * Copyright 2001-2008 S3 Graphics, Inc. All Rights Reserved.

 */

#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/via-core.h>
#include <linux/via_i2c.h>

/*
 * There can only be one set of these, so there's no point in having
 * them be dynamically allocated...
 */
#define VIAFB_NUM_I2C           5
static struct via_i2c_stuff via_i2c_par[VIAFB_NUM_I2C];
static struct viafb_dev *i2c_vdev;  /* Passed in from core */

static void via_i2c_setscl(void *data, int state)
{
        u8 val;
        struct via_port_cfg *adap_data = data;
        unsigned long flags;

        spin_lock_irqsave(&i2c_vdev->reg_lock, flags);
        val = via_read_reg(adap_data->io_port, adap_data->ioport_index) & 0xF0;
        if (state)
                val |= 0x20;
        else
                val &= ~0x20;
        switch (adap_data->type) {
        case VIA_PORT_I2C:
                val |= 0x01;
                break;
        case VIA_PORT_GPIO:
                val |= 0x82;
                break;
        default:
                printk(KERN_ERR "viafb_i2c: specify wrong i2c type.\n");
        }
        via_write_reg(adap_data->io_port, adap_data->ioport_index, val);
        spin_unlock_irqrestore(&i2c_vdev->reg_lock, flags);
}

static int via_i2c_getscl(void *data)
{
        struct via_port_cfg *adap_data = data;
        unsigned long flags;
        int ret = 0;

        spin_lock_irqsave(&i2c_vdev->reg_lock, flags);
        if (adap_data->type == VIA_PORT_GPIO)
                via_write_reg_mask(adap_data->io_port, adap_data->ioport_index,
                        0, 0x80);
        if (via_read_reg(adap_data->io_port, adap_data->ioport_index) & 0x08)
                ret = 1;
        spin_unlock_irqrestore(&i2c_vdev->reg_lock, flags);
        return ret;
}

static int via_i2c_getsda(void *data)
{
        struct via_port_cfg *adap_data = data;
        unsigned long flags;
        int ret = 0;

        spin_lock_irqsave(&i2c_vdev->reg_lock, flags);
        if (adap_data->type == VIA_PORT_GPIO)
                via_write_reg_mask(adap_data->io_port, adap_data->ioport_index,
                        0, 0x40);
        if (via_read_reg(adap_data->io_port, adap_data->ioport_index) & 0x04)
                ret = 1;
        spin_unlock_irqrestore(&i2c_vdev->reg_lock, flags);
        return ret;
}

static void via_i2c_setsda(void *data, int state)
{
        u8 val;
        struct via_port_cfg *adap_data = data;
        unsigned long flags;

        spin_lock_irqsave(&i2c_vdev->reg_lock, flags);
        val = via_read_reg(adap_data->io_port, adap_data->ioport_index) & 0xF0;
        if (state)
                val |= 0x10;
        else
                val &= ~0x10;
        switch (adap_data->type) {
        case VIA_PORT_I2C:
                val |= 0x01;
                break;
        case VIA_PORT_GPIO:
                val |= 0x42;
                break;
        default:
                printk(KERN_ERR "viafb_i2c: specify wrong i2c type.\n");
        }
        via_write_reg(adap_data->io_port, adap_data->ioport_index, val);
        spin_unlock_irqrestore(&i2c_vdev->reg_lock, flags);
}

int viafb_i2c_readbyte(u8 adap, u8 target_addr, u8 index, u8 *pdata)
{
        int ret;
        u8 mm1[] = {0x00};
        struct i2c_msg msgs[2];

        if (!via_i2c_par[adap].is_active)
                return -ENODEV;
        *pdata = 0;
        msgs[0].flags = 0;
        msgs[1].flags = I2C_M_RD;
        msgs[0].addr = msgs[1].addr = target_addr / 2;
        mm1[0] = index;
        msgs[0].len = 1; msgs[1].len = 1;
        msgs[0].buf = mm1; msgs[1].buf = pdata;
        ret = i2c_transfer(&via_i2c_par[adap].adapter, msgs, 2);
        if (ret == 2)
                ret = 0;
        else if (ret >= 0)
                ret = -EIO;

        return ret;
}

int viafb_i2c_writebyte(u8 adap, u8 target_addr, u8 index, u8 data)
{
        int ret;
        u8 msg[2] = { index, data };
        struct i2c_msg msgs;

        if (!via_i2c_par[adap].is_active)
                return -ENODEV;
        msgs.flags = 0;
        msgs.addr = target_addr / 2;
        msgs.len = 2;
        msgs.buf = msg;
        ret = i2c_transfer(&via_i2c_par[adap].adapter, &msgs, 1);
        if (ret == 1)
                ret = 0;
        else if (ret >= 0)
                ret = -EIO;

        return ret;
}

int viafb_i2c_readbytes(u8 adap, u8 target_addr, u8 index, u8 *buff, int buff_len)
{
        int ret;
        u8 mm1[] = {0x00};
        struct i2c_msg msgs[2];

        if (!via_i2c_par[adap].is_active)
                return -ENODEV;
        msgs[0].flags = 0;
        msgs[1].flags = I2C_M_RD;
        msgs[0].addr = msgs[1].addr = target_addr / 2;
        mm1[0] = index;
        msgs[0].len = 1; msgs[1].len = buff_len;
        msgs[0].buf = mm1; msgs[1].buf = buff;
        ret = i2c_transfer(&via_i2c_par[adap].adapter, msgs, 2);
        if (ret == 2)
                ret = 0;
        else if (ret >= 0)
                ret = -EIO;

        return ret;
}

/*
 * Allow other viafb subdevices to look up a specific adapter
 * by port name.
 */
struct i2c_adapter *viafb_find_i2c_adapter(enum viafb_i2c_adap which)
{
        struct via_i2c_stuff *stuff = &via_i2c_par[which];

        return &stuff->adapter;
}
EXPORT_SYMBOL_GPL(viafb_find_i2c_adapter);


static int create_i2c_bus(struct i2c_adapter *adapter,
                          struct i2c_algo_bit_data *algo,
                          struct via_port_cfg *adap_cfg,
                          struct pci_dev *pdev)
{
        algo->setsda = via_i2c_setsda;
        algo->setscl = via_i2c_setscl;
        algo->getsda = via_i2c_getsda;
        algo->getscl = via_i2c_getscl;
        algo->udelay = 10;
        algo->timeout = 2;
        algo->data = adap_cfg;

        sprintf(adapter->name, "viafb i2c io_port idx 0x%02x",
                adap_cfg->ioport_index);
        adapter->owner = THIS_MODULE;
        adapter->algo_data = algo;
        if (pdev)
                adapter->dev.parent = &pdev->dev;
        else
                adapter->dev.parent = NULL;
        /* i2c_set_adapdata(adapter, adap_cfg); */

        /* Raise SCL and SDA */
        via_i2c_setsda(adap_cfg, 1);
        via_i2c_setscl(adap_cfg, 1);
        udelay(20);

        return i2c_bit_add_bus(adapter);
}

static int viafb_i2c_probe(struct platform_device *platdev)
{
        int i, ret;
        struct via_port_cfg *configs;

        i2c_vdev = platdev->dev.platform_data;
        configs = i2c_vdev->port_cfg;

        for (i = 0; i < VIAFB_NUM_PORTS; i++) {
                struct via_port_cfg *adap_cfg = configs++;
                struct via_i2c_stuff *i2c_stuff = &via_i2c_par[i];

                i2c_stuff->is_active = 0;
                if (adap_cfg->type == 0 || adap_cfg->mode != VIA_MODE_I2C)
                        continue;
                ret = create_i2c_bus(&i2c_stuff->adapter,
                                     &i2c_stuff->algo, adap_cfg,
                                NULL); /* FIXME: PCIDEV */
                if (ret < 0) {
                        printk(KERN_ERR "viafb: cannot create i2c bus %u:%d\n",
                                i, ret);
                        continue;  /* Still try to make the rest */
                }
                i2c_stuff->is_active = 1;
        }

        return 0;
}

static void viafb_i2c_remove(struct platform_device *platdev)
{
        int i;

        for (i = 0; i < VIAFB_NUM_PORTS; i++) {
                struct via_i2c_stuff *i2c_stuff = &via_i2c_par[i];
                /*
                 * Only remove those entries in the array that we've
                 * actually used (and thus initialized algo_data)
                 */
                if (i2c_stuff->is_active)
                        i2c_del_adapter(&i2c_stuff->adapter);
        }
}

static struct platform_driver via_i2c_driver = {
        .driver = {
                .name = "viafb-i2c",
        },
        .probe = viafb_i2c_probe,
        .remove = viafb_i2c_remove,
};

int viafb_i2c_init(void)
{
        return platform_driver_register(&via_i2c_driver);
}

void viafb_i2c_exit(void)
{
        platform_driver_unregister(&via_i2c_driver);
}