/*
 * linux/drivers/video/nvidia/nvidia-i2c.c - nVidia i2c
 *
 * Copyright 2004 Antonino A. Daplas <adaplas @pol.net>
 *
 * Based on rivafb-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/gfp.h>
#include <linux/pci.h>
#include <linux/fb.h>

#include <asm/io.h>

#include "nv_type.h"
#include "nv_local.h"
#include "nv_proto.h"

#include "../edid.h"

static void nvidia_gpio_setscl(void *data, int state)
{
        struct nvidia_i2c_chan *chan = data;
        struct nvidia_par *par = chan->par;
        u32 val;

        val = NVReadCrtc(par, chan->ddc_base + 1) & 0xf0;

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

        NVWriteCrtc(par, chan->ddc_base + 1, val | 0x01);
}

static void nvidia_gpio_setsda(void *data, int state)
{
        struct nvidia_i2c_chan *chan = data;
        struct nvidia_par *par = chan->par;
        u32 val;

        val = NVReadCrtc(par, chan->ddc_base + 1) & 0xf0;

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

        NVWriteCrtc(par, chan->ddc_base + 1, val | 0x01);
}

static int nvidia_gpio_getscl(void *data)
{
        struct nvidia_i2c_chan *chan = data;
        struct nvidia_par *par = chan->par;
        u32 val = 0;

        if (NVReadCrtc(par, chan->ddc_base) & 0x04)
                val = 1;

        return val;
}

static int nvidia_gpio_getsda(void *data)
{
        struct nvidia_i2c_chan *chan = data;
        struct nvidia_par *par = chan->par;
        u32 val = 0;

        if (NVReadCrtc(par, chan->ddc_base) & 0x08)
                val = 1;

        return val;
}

static int nvidia_setup_i2c_bus(struct nvidia_i2c_chan *chan, const char *name,
                                unsigned int i2c_class)
{
        int rc;

        strscpy(chan->adapter.name, name, sizeof(chan->adapter.name));
        chan->adapter.owner = THIS_MODULE;
        chan->adapter.class = i2c_class;
        chan->adapter.algo_data = &chan->algo;
        chan->adapter.dev.parent = &chan->par->pci_dev->dev;
        chan->algo.setsda = nvidia_gpio_setsda;
        chan->algo.setscl = nvidia_gpio_setscl;
        chan->algo.getsda = nvidia_gpio_getsda;
        chan->algo.getscl = nvidia_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 */
        nvidia_gpio_setsda(chan, 1);
        nvidia_gpio_setscl(chan, 1);
        udelay(20);

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

        return rc;
}

void nvidia_create_i2c_busses(struct nvidia_par *par)
{
        par->chan[0].par = par;
        par->chan[1].par = par;
        par->chan[2].par = par;

        par->chan[0].ddc_base = (par->reverse_i2c) ? 0x36 : 0x3e;
        nvidia_setup_i2c_bus(&par->chan[0], "nvidia #0",
                             (par->reverse_i2c) ? I2C_CLASS_HWMON : 0);

        par->chan[1].ddc_base = (par->reverse_i2c) ? 0x3e : 0x36;
        nvidia_setup_i2c_bus(&par->chan[1], "nvidia #1",
                             (par->reverse_i2c) ? 0 : I2C_CLASS_HWMON);

        par->chan[2].ddc_base = 0x50;
        nvidia_setup_i2c_bus(&par->chan[2], "nvidia #2", 0);
}

void nvidia_delete_i2c_busses(struct nvidia_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 nvidia_probe_i2c_connector(struct fb_info *info, int conn, u8 **out_edid)
{
        struct nvidia_par *par = info->par;
        u8 *edid = NULL;

        if (par->chan[conn - 1].par)
                edid = fb_ddc_read(&par->chan[conn - 1].adapter);

        if (!edid && conn == 1) {
                /* try to get from firmware */
                const u8 *e = fb_firmware_edid(info->device);

                if (e != NULL)
                        edid = kmemdup(e, EDID_LENGTH, GFP_KERNEL);
        }

        *out_edid = edid;

        return (edid) ? 0 : 1;
}