/*
 * 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/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/delay.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

#define SET_CR_IX(base, val)	writeb((val), base + 0x8000 + VGA_CR_IX)
#define SET_CR_DATA(base, val)	writeb((val), base + 0x8000 + VGA_CR_DATA)
#define GET_CR_DATA(base)	readb(base + 0x8000 + VGA_CR_DATA)

static void savage4_gpio_setscl(void *data, int val)
{
	struct savagefb_i2c_chan *chan = (struct savagefb_i2c_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 = (struct savagefb_i2c_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 = (struct savagefb_i2c_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 = (struct savagefb_i2c_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 = (struct savagefb_i2c_chan *)data;
	u32			  r;

	SET_CR_IX(chan->ioaddr, chan->reg);
	r = GET_CR_DATA(chan->ioaddr);
	r |= PROSAVAGE_I2C_ENAB;
	if (val) {
		r |= PROSAVAGE_I2C_SCL_OUT;
	} else {
		r &= ~PROSAVAGE_I2C_SCL_OUT;
	}
	SET_CR_DATA(chan->ioaddr, r);
}

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

	SET_CR_IX(chan->ioaddr, chan->reg);
	r = GET_CR_DATA(chan->ioaddr);
	r |= PROSAVAGE_I2C_ENAB;
	if (val) {
		r |= PROSAVAGE_I2C_SDA_OUT;
	} else {
		r &= ~PROSAVAGE_I2C_SDA_OUT;
	}
	SET_CR_DATA(chan->ioaddr, r);
}

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

	SET_CR_IX(chan->ioaddr, chan->reg);
	return (0 != (GET_CR_DATA(chan->ioaddr) & PROSAVAGE_I2C_SCL_IN));
}

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

	SET_CR_IX(chan->ioaddr, chan->reg);
	return (0 != (GET_CR_DATA(chan->ioaddr) & PROSAVAGE_I2C_SDA_IN));
}

static int savage_setup_i2c_bus(struct savagefb_i2c_chan *chan,
				const char *name)
{
	int (*add_bus)(struct i2c_adapter *) = symbol_get(i2c_bit_add_bus);
	int rc = 0;

	if (add_bus && chan->par) {
		strcpy(chan->adapter.name, name);
		chan->adapter.owner		= THIS_MODULE;
		chan->adapter.id		= I2C_HW_B_SAVAGE;
		chan->adapter.algo_data		= &chan->algo;
		chan->adapter.dev.parent	= &chan->par->pcidev->dev;
		chan->algo.udelay		= 40;
		chan->algo.mdelay               = 5;
		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 = 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);

		symbol_put(i2c_bit_add_bus);
	} else
		chan->par = NULL;

	return rc;
}

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

	switch(info->fix.accel) {
	case FB_ACCEL_PROSAVAGE_DDRK:
	case FB_ACCEL_PROSAVAGE_PM:
		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 FB_ACCEL_SAVAGE4:
		par->chan.reg         = 0xff20;
		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 = (struct savagefb_par *)info->par;
	int (*del_bus)(struct i2c_adapter *) =
		symbol_get(i2c_bit_del_bus);

	if (del_bus && par->chan.par) {
		del_bus(&par->chan.adapter);
		symbol_put(i2c_bit_del_bus);
	}

	par->chan.par = NULL;
}

static u8 *savage_do_probe_i2c_edid(struct savagefb_i2c_chan *chan)
{
	u8 start = 0x0;
	int (*transfer)(struct i2c_adapter *, struct i2c_msg *, int) =
		symbol_get(i2c_transfer);
	struct i2c_msg msgs[] = {
		{
			.addr	= SAVAGE_DDC,
			.len	= 1,
			.buf	= &start,
		}, {
			.addr	= SAVAGE_DDC,
			.flags	= I2C_M_RD,
			.len	= EDID_LENGTH,
		},
	};
	u8 *buf = NULL;

	if (transfer && chan->par) {
		buf = kmalloc(EDID_LENGTH, GFP_KERNEL);

		if (buf) {
			msgs[1].buf = buf;

			if (transfer(&chan->adapter, msgs, 2) != 2) {
				dev_dbg(&chan->par->pcidev->dev,
					"Unable to read EDID block.\n");
				kfree(buf);
				buf = NULL;
			}
		}

		symbol_put(i2c_transfer);
	}

	return buf;
}

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

	for (i = 0; i < 3; i++) {
		/* Do the real work */
		edid = savage_do_probe_i2c_edid(&par->chan);
		if (edid)
			break;
	}

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

		if (e) {
			edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
			if (edid)
				memcpy(edid, e, EDID_LENGTH);
		}
	}

	if (out_edid)
		*out_edid = edid;

	return (edid) ? 0 : 1;
}

MODULE_LICENSE("GPL");