/*
 * linux/drivers/video/riva/fbdev-i2c.c - nVidia i2c
 *
 * Maintained by Ani Joshi <ajoshi@shell.unixbox.com>
 *
 * Copyright 2004 Antonino A. Daplas <adaplas @pol.net>
 *
 * Based on radeonfb-i2c.c
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/fb.h>
#include <linux/jiffies.h>

#include <asm/io.h>

#include "rivafb.h"
#include "../edid.h"

static void riva_gpio_setscl(void* data, int state)
{
        struct riva_i2c_chan    *chan = data;
        struct riva_par         *par = chan->par;
        u32                     val;

        VGA_WR08(par->riva.PCIO, 0x3d4, chan->ddc_base + 1);
        val = VGA_RD08(par->riva.PCIO, 0x3d5) & 0xf0;

        if (state)
                val |= 0x20;
        else
                val &= ~0x20;

        VGA_WR08(par->riva.PCIO, 0x3d4, chan->ddc_base + 1);
        VGA_WR08(par->riva.PCIO, 0x3d5, val | 0x1);
}

static void riva_gpio_setsda(void* data, int state)
{
        struct riva_i2c_chan    *chan = data;
        struct riva_par         *par = chan->par;
        u32                     val;

        VGA_WR08(par->riva.PCIO, 0x3d4, chan->ddc_base + 1);
        val = VGA_RD08(par->riva.PCIO, 0x3d5) & 0xf0;

        if (state)
                val |= 0x10;
        else
                val &= ~0x10;

        VGA_WR08(par->riva.PCIO, 0x3d4, chan->ddc_base + 1);
        VGA_WR08(par->riva.PCIO, 0x3d5, val | 0x1);
}

static int riva_gpio_getscl(void* data)
{
        struct riva_i2c_chan    *chan = data;
        struct riva_par         *par = chan->par;
        u32                     val = 0;

        VGA_WR08(par->riva.PCIO, 0x3d4, chan->ddc_base);
        if (VGA_RD08(par->riva.PCIO, 0x3d5) & 0x04)
                val = 1;

        return val;
}

static int riva_gpio_getsda(void* data)
{
        struct riva_i2c_chan    *chan = data;
        struct riva_par         *par = chan->par;
        u32                     val = 0;

        VGA_WR08(par->riva.PCIO, 0x3d4, chan->ddc_base);
        if (VGA_RD08(par->riva.PCIO, 0x3d5) & 0x08)
                val = 1;

        return val;
}

static int riva_setup_i2c_bus(struct riva_i2c_chan *chan, const char *name,
                              unsigned int i2c_class)
{
        int rc;

        strcpy(chan->adapter.name, name);
        chan->adapter.owner             = THIS_MODULE;
        chan->adapter.class             = i2c_class;
        chan->adapter.algo_data         = &chan->algo;
        chan->adapter.dev.parent        = &chan->par->pdev->dev;
        chan->algo.setsda               = riva_gpio_setsda;
        chan->algo.setscl               = riva_gpio_setscl;
        chan->algo.getsda               = riva_gpio_getsda;
        chan->algo.getscl               = riva_gpio_getscl;
        chan->algo.udelay               = 40;
        chan->algo.timeout              = msecs_to_jiffies(2);
        chan->algo.data                 = chan;

        i2c_set_adapdata(&chan->adapter, chan);

        /* Raise SCL and SDA */
        riva_gpio_setsda(chan, 1);
        riva_gpio_setscl(chan, 1);
        udelay(20);

        rc = i2c_bit_add_bus(&chan->adapter);
        if (rc == 0)
                dev_dbg(&chan->par->pdev->dev, "I2C bus %s registered.\n", name);
        else {
                dev_warn(&chan->par->pdev->dev,
                         "Failed to register I2C bus %s.\n", name);
                chan->par = NULL;
        }

        return rc;
}

void riva_create_i2c_busses(struct riva_par *par)
{
        par->chan[0].par        = par;
        par->chan[1].par        = par;
        par->chan[2].par        = par;

        par->chan[0].ddc_base = 0x36;
        par->chan[1].ddc_base = 0x3e;
        par->chan[2].ddc_base = 0x50;
        riva_setup_i2c_bus(&par->chan[0], "BUS1", I2C_CLASS_HWMON);
        riva_setup_i2c_bus(&par->chan[1], "BUS2", 0);
        riva_setup_i2c_bus(&par->chan[2], "BUS3", 0);
}

void riva_delete_i2c_busses(struct riva_par *par)
{
        int i;

        for (i = 0; i < 3; i++) {
                if (!par->chan[i].par)
                        continue;
                i2c_del_adapter(&par->chan[i].adapter);
                par->chan[i].par = NULL;
        }
}

int riva_probe_i2c_connector(struct riva_par *par, int conn, u8 **out_edid)
{
        u8 *edid = NULL;

        if (par->chan[conn].par)
                edid = fb_ddc_read(&par->chan[conn].adapter);

        if (out_edid)
                *out_edid = edid;
        if (!edid)
                return 1;

        return 0;
}