/*
 * Remote control driver for the TV-card based on bt829
 *
 *  by Leonid Froenchenko <lfroen@galileo.co.il>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <linux/version.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 4, 0)
#error "This driver needs kernel version 2.4.0 or higher"
#endif

#include <linux/autoconf.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/threads.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/pci.h>
#include <linux/delay.h>

#include "kcompat.h"
#include "lirc_dev/lirc_dev.h"

static int poll_main(void);
static int atir_init_start(void);

static void write_index(unsigned char index, unsigned int value);
static unsigned int read_index(unsigned char index);

static void do_i2c_start(void);
static void do_i2c_stop(void);

static void seems_wr_byte(unsigned char al);
static unsigned char seems_rd_byte(void);

static unsigned int read_index(unsigned char al);
static void write_index(unsigned char ah, unsigned int edx);

static void cycle_delay(int cycle);

static void do_set_bits(unsigned char bl);
static unsigned char do_get_bits(void);

#define DATA_PCI_OFF 0x7FFC00
#define WAIT_CYCLE   20

static int debug;
#define dprintk(fmt, args...)					\
	do {							\
		if (debug)					\
			printk(KERN_DEBUG fmt, ## args);	\
	} while (0)

static int atir_minor;
static unsigned long pci_addr_phys;
static unsigned char *pci_addr_lin;

static struct lirc_plugin atir_plugin;

static struct pci_dev *do_pci_probe(void)
{
	struct pci_dev *my_dev;
#ifndef KERNEL_2_5
	/* unnecessary with recent kernels */
	if (!pci_present())
		printk(KERN_ERR "ATIR: no pci in this kernel\n");
#endif
	my_dev = pci_get_device(PCI_VENDOR_ID_ATI,
				PCI_DEVICE_ID_ATI_264VT, NULL);
	if (my_dev) {
		printk(KERN_ERR "ATIR: Using device: %s\n",
		       pci_name(my_dev));
		pci_addr_phys = 0;
		if (my_dev->resource[0].flags & IORESOURCE_MEM) {
			pci_addr_phys = my_dev->resource[0].start;
			printk(KERN_INFO "ATIR memory at 0x%08X \n",
			       (unsigned int)pci_addr_phys);
		}
		if (pci_addr_phys == 0) {
			printk(KERN_ERR "ATIR no memory resource ?\n");
			return NULL;
		}
	} else {
		printk(KERN_ERR "ATIR: pci_prob failed\n");
		return NULL;
	}
	return my_dev;
}

static int atir_add_to_buf(void *data, struct lirc_buffer *buf)
{
	unsigned char key;
	int status;
	status = poll_main();
	key = (status >> 8) & 0xFF;
	if (status & 0xFF) {
		dprintk("ATIR reading key %02X\n", key);
		lirc_buffer_write_1(buf, &key);
		return 0;
	}
	return -ENODATA;
}

static int atir_set_use_inc(void *data)
{
	MOD_INC_USE_COUNT;
	dprintk("ATIR driver is opened\n");
	return 0;
}

static void atir_set_use_dec(void *data)
{
	MOD_DEC_USE_COUNT;
	dprintk("ATIR driver is closed\n");
}

int init_module(void)
{
	struct pci_dev *pdev;

	pdev = do_pci_probe();
	if (pdev == NULL)
		return 1;

	if (!atir_init_start())
		return 1;

	strcpy(atir_plugin.name, "ATIR");
	atir_plugin.minor       = -1;
	atir_plugin.code_length = 8;
	atir_plugin.sample_rate = 10;
	atir_plugin.data        = 0;
	atir_plugin.add_to_buf  = atir_add_to_buf;
	atir_plugin.set_use_inc = atir_set_use_inc;
	atir_plugin.set_use_dec = atir_set_use_dec;
#ifdef LIRC_HAVE_SYSFS
	atir_plugin.dev         = &pdev->dev;
#endif
	atir_plugin.owner       = THIS_MODULE;

	atir_minor = lirc_register_plugin(&atir_plugin);
	dprintk("ATIR driver is registered on minor %d\n", atir_minor);

	return 0;
}


void cleanup_module(void)
{
	lirc_unregister_plugin(atir_minor);
}


static int atir_init_start(void)
{
	pci_addr_lin = ioremap(pci_addr_phys + DATA_PCI_OFF, 0x400);
	if (pci_addr_lin == 0) {
		printk(KERN_INFO "atir: pci mem must be mapped\n");
		return 0;
	}
	return 1;
}

static void cycle_delay(int cycle)
{
	udelay(WAIT_CYCLE*cycle);
}


static int poll_main()
{
	unsigned char status_high, status_low;

	do_i2c_start();

	seems_wr_byte(0xAA);
	seems_wr_byte(0x01);

	do_i2c_start();

	seems_wr_byte(0xAB);

	status_low = seems_rd_byte();
	status_high = seems_rd_byte();

	do_i2c_stop();

	return (status_high << 8) | status_low;
}

static void do_i2c_start(void)
{
	do_set_bits(3);
	cycle_delay(4);

	do_set_bits(1);
	cycle_delay(7);

	do_set_bits(0);
	cycle_delay(2);
}

static void do_i2c_stop(void)
{
	unsigned char bits;
	bits =  do_get_bits() & 0xFD;
	do_set_bits(bits);
	cycle_delay(1);

	bits |= 1;
	do_set_bits(bits);
	cycle_delay(2);

	bits |= 2;
	do_set_bits(bits);
	bits = 3;
	do_set_bits(bits);
	cycle_delay(2);
}

static void seems_wr_byte(unsigned char value)
{
	int i;
	unsigned char reg;

	reg = do_get_bits();
	for (i = 0; i < 8; i++) {
		if (value & 0x80)
			reg |= 0x02;
		else
			reg &= 0xFD;

		do_set_bits(reg);
		cycle_delay(1);

		reg |= 1;
		do_set_bits(reg);
		cycle_delay(1);

		reg &= 0xFE;
		do_set_bits(reg);
		cycle_delay(1);
		value <<= 1;
	}
	cycle_delay(2);

	reg |= 2;
	do_set_bits(reg);

	reg |= 1;
	do_set_bits(reg);

	cycle_delay(1);
	do_get_bits();

	reg &= 0xFE;
	do_set_bits(reg);
	cycle_delay(3);
}

static unsigned char seems_rd_byte(void)
{
	int i;
	int rd_byte;
	unsigned char bits_2, bits_1;

	bits_1 = do_get_bits() | 2;
	do_set_bits(bits_1);

	rd_byte = 0;
	for (i = 0; i < 8; i++) {
		bits_1 &= 0xFE;
		do_set_bits(bits_1);
		cycle_delay(2);

		bits_1 |= 1;
		do_set_bits(bits_1);
		cycle_delay(1);

		bits_2 = do_get_bits();
		if (bits_2 & 2)
			rd_byte |= 1;

		rd_byte <<= 1;
	}

	bits_1 = 0;
	if (bits_2 == 0)
		bits_1 |= 2;

	do_set_bits(bits_1);
	cycle_delay(2);

	bits_1 |= 1;
	do_set_bits(bits_1);
	cycle_delay(3);

	bits_1 &= 0xFE;
	do_set_bits(bits_1);
	cycle_delay(2);

	rd_byte >>= 1;
	rd_byte &= 0xFF;
	return rd_byte;
}

static void do_set_bits(unsigned char new_bits)
{
	int reg_val;
	reg_val = read_index(0x34);
	if (new_bits & 2) {
		reg_val &= 0xFFFFFFDF;
		reg_val |= 1;
	} else {
		reg_val &= 0xFFFFFFFE;
		reg_val |= 0x20;
	}
	reg_val |= 0x10;
	write_index(0x34, reg_val);

	reg_val = read_index(0x31);
	if (new_bits & 1) {
		reg_val |= 0x1000000;
	} else {
		reg_val &= 0xFEFFFFFF;
	}
	reg_val |= 0x8000000;
	write_index(0x31, reg_val);
}

static unsigned char do_get_bits(void)
{
	unsigned char bits;
	int reg_val;

	reg_val = read_index(0x34);
	reg_val |= 0x10;
	reg_val &= 0xFFFFFFDF;
	write_index(0x34, reg_val);

	reg_val = read_index(0x34);
	bits = 0;
	if (reg_val & 8) {
		bits |= 2;
	} else {
		bits &= 0xFD;
	}
	reg_val = read_index(0x31);
	if (reg_val & 0x1000000) {
		bits |= 1;
	} else {
		bits &= 0xFE;
	}
	return bits;
}

static unsigned int read_index(unsigned char index)
{
	unsigned char *addr;
	unsigned int value;
	/*  addr = pci_addr_lin + DATA_PCI_OFF + ((index & 0xFF) << 2); */
	addr = pci_addr_lin + ((index & 0xFF) << 2);
	value = readl(addr);
	return value;
}

static void write_index(unsigned char index, unsigned int reg_val)
{
	unsigned char *addr;
	addr = pci_addr_lin + ((index & 0xFF) << 2);
	writel(reg_val, addr);
}

MODULE_AUTHOR("Froenchenko Leonid");
MODULE_DESCRIPTION("IR remote driver for bt829 based TV cards");
MODULE_LICENSE("GPL");

module_param(debug, bool, 0644);
MODULE_PARM_DESC(debug, "Debug enabled or not");

EXPORT_NO_SYMBOLS;

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-basic-offset: 8
 * End:
 */
