/*
 * linux/drivers/video/savage/savagefb-i2c.c - S3 Savage DDC2
 *
 * Copyright 2004 Antonino A. Daplas <adaplas @pol.net>
 *
 * Based partly 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 "savagefb.h"

#define SAVAGE_DDC      0x50

#define VGA_CR_IX       0x3d4
#define VGA_CR_DATA     0x3d5

#define CR_SERIAL1      0xa0    /* I2C serial communications interface */
#define MM_SERIAL1      0xff20
#define CR_SERIAL2      0xb1    /* DDC2 monitor communications interface */

/* based on vt8365 documentation */
#define PROSAVAGE_I2C_ENAB      0x10
#define PROSAVAGE_I2C_SCL_OUT   0x01
#define PROSAVAGE_I2C_SDA_OUT   0x02
#define PROSAVAGE_I2C_SCL_IN    0x04
#define PROSAVAGE_I2C_SDA_IN    0x08

#define SAVAGE4_I2C_ENAB        0x00000020
#define SAVAGE4_I2C_SCL_OUT     0x00000001
#define SAVAGE4_I2C_SDA_OUT     0x00000002
#define SAVAGE4_I2C_SCL_IN      0x00000008
#define SAVAGE4_I2C_SDA_IN      0x00000010

static void savage4_gpio_setscl(void *data, int val)
{
        struct savagefb_i2c_chan *chan = data;
        unsigned int r;

        r = readl(chan->ioaddr + chan->reg);
        if(val)
                r |= SAVAGE4_I2C_SCL_OUT;
        else
                r &= ~SAVAGE4_I2C_SCL_OUT;
        writel(r, chan->ioaddr + chan->reg);
        readl(chan->ioaddr + chan->reg);        /* flush posted write */
}

static void savage4_gpio_setsda(void *data, int val)
{
        struct savagefb_i2c_chan *chan = data;

        unsigned int r;
        r = readl(chan->ioaddr + chan->reg);
        if(val)
                r |= SAVAGE4_I2C_SDA_OUT;
        else
                r &= ~SAVAGE4_I2C_SDA_OUT;
        writel(r, chan->ioaddr + chan->reg);
        readl(chan->ioaddr + chan->reg);        /* flush posted write */
}

static int savage4_gpio_getscl(void *data)
{
        struct savagefb_i2c_chan *chan = data;

        return (0 != (readl(chan->ioaddr + chan->reg) & SAVAGE4_I2C_SCL_IN));
}

static int savage4_gpio_getsda(void *data)
{
        struct savagefb_i2c_chan *chan = data;

        return (0 != (readl(chan->ioaddr + chan->reg) & SAVAGE4_I2C_SDA_IN));
}

static void prosavage_gpio_setscl(void* data, int val)
{
        struct savagefb_i2c_chan *chan = data;
        u32                       r;

        r = VGArCR(chan->reg, chan->par);
        r |= PROSAVAGE_I2C_ENAB;
        if (val) {
                r |= PROSAVAGE_I2C_SCL_OUT;
        } else {
                r &= ~PROSAVAGE_I2C_SCL_OUT;
        }

        VGAwCR(chan->reg, r, chan->par);
}

static void prosavage_gpio_setsda(void* data, int val)
{
        struct savagefb_i2c_chan *chan = data;
        unsigned int r;

        r = VGArCR(chan->reg, chan->par);
        r |= PROSAVAGE_I2C_ENAB;
        if (val) {
                r |= PROSAVAGE_I2C_SDA_OUT;
        } else {
                r &= ~PROSAVAGE_I2C_SDA_OUT;
        }

        VGAwCR(chan->reg, r, chan->par);
}

static int prosavage_gpio_getscl(void* data)
{
        struct savagefb_i2c_chan *chan = data;

        return (VGArCR(chan->reg, chan->par) & PROSAVAGE_I2C_SCL_IN) ? 1 : 0;
}

static int prosavage_gpio_getsda(void* data)
{
        struct savagefb_i2c_chan *chan = data;

        return (VGArCR(chan->reg, chan->par) & PROSAVAGE_I2C_SDA_IN) ? 1 : 0;
}

static int savage_setup_i2c_bus(struct savagefb_i2c_chan *chan,
                                const char *name)
{
        int rc = 0;

        if (chan->par) {
                strcpy(chan->adapter.name, name);
                chan->adapter.owner             = THIS_MODULE;
                chan->adapter.algo_data         = &chan->algo;
                chan->adapter.dev.parent        = &chan->par->pcidev->dev;
                chan->algo.udelay               = 10;
                chan->algo.timeout              = 20;
                chan->algo.data                 = chan;

                i2c_set_adapdata(&chan->adapter, chan);

                /* Raise SCL and SDA */
                chan->algo.setsda(chan, 1);
                chan->algo.setscl(chan, 1);
                udelay(20);

                rc = i2c_bit_add_bus(&chan->adapter);

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

        return rc;
}

void savagefb_create_i2c_busses(struct fb_info *info)
{
        struct savagefb_par *par = info->par;
        par->chan.par   = par;

        switch (par->chip) {
        case S3_PROSAVAGE:
        case S3_PROSAVAGEDDR:
        case S3_TWISTER:
                par->chan.reg         = CR_SERIAL2;
                par->chan.ioaddr      = par->mmio.vbase;
                par->chan.algo.setsda = prosavage_gpio_setsda;
                par->chan.algo.setscl = prosavage_gpio_setscl;
                par->chan.algo.getsda = prosavage_gpio_getsda;
                par->chan.algo.getscl = prosavage_gpio_getscl;
                break;
        case S3_SAVAGE4:
                par->chan.reg = CR_SERIAL1;
                if (par->pcidev->revision > 1 && !(VGArCR(0xa6, par) & 0x40))
                        par->chan.reg = CR_SERIAL2;
                par->chan.ioaddr      = par->mmio.vbase;
                par->chan.algo.setsda = prosavage_gpio_setsda;
                par->chan.algo.setscl = prosavage_gpio_setscl;
                par->chan.algo.getsda = prosavage_gpio_getsda;
                par->chan.algo.getscl = prosavage_gpio_getscl;
                break;
        case S3_SAVAGE2000:
                par->chan.reg         = MM_SERIAL1;
                par->chan.ioaddr      = par->mmio.vbase;
                par->chan.algo.setsda = savage4_gpio_setsda;
                par->chan.algo.setscl = savage4_gpio_setscl;
                par->chan.algo.getsda = savage4_gpio_getsda;
                par->chan.algo.getscl = savage4_gpio_getscl;
                break;
        default:
                par->chan.par = NULL;
        }

        savage_setup_i2c_bus(&par->chan, "SAVAGE DDC2");
}

void savagefb_delete_i2c_busses(struct fb_info *info)
{
        struct savagefb_par *par = info->par;

        if (par->chan.par)
                i2c_del_adapter(&par->chan.adapter);

        par->chan.par = NULL;
}

int savagefb_probe_i2c_connector(struct fb_info *info, u8 **out_edid)
{
        struct savagefb_par *par = info->par;
        u8 *edid;

        if (par->chan.par)
                edid = fb_ddc_read(&par->chan.adapter);
        else
                edid = NULL;

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

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

        *out_edid = edid;

        return (edid) ? 0 : 1;
}

MODULE_LICENSE("GPL");