/*
 * Driver for Philips SAB3036 "CITAC" tuner control chip.
 *
 * Author: Phil Blundell <philb@gnu.org>
 *
 * The SAB3036 is just about different enough from the chips that
 * tuner.c copes with to make it not worth the effort to crowbar
 * the support into that file.  So instead we have a separate driver.
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/init.h>

#include <linux/i2c.h>
#include <linux/videodev.h>
#include <media/v4l2-common.h>

#include <media/tuner.h>

static int debug;       /* insmod parameter */
static int this_adap;

static struct i2c_client client_template;

/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x60, 0x61, I2C_CLIENT_END };
static unsigned short ignore = I2C_CLIENT_END;

static struct i2c_client_address_data addr_data = {
        .normal_i2c     = normal_i2c,
        .probe          = &ignore,
        .ignore         = &ignore,
};

/* ---------------------------------------------------------------------- */

static unsigned char
tuner_getstatus (struct i2c_client *c)
{
        unsigned char byte;
        if (i2c_master_recv(c, &byte, 1) != 1)
                printk(KERN_ERR "tuner-3036: I/O error.\n");
        return byte;
}

#define TUNER_FL        0x80

static int
tuner_islocked (struct i2c_client *c)
{
        return (tuner_getstatus(c) & TUNER_FL);
}

/* ---------------------------------------------------------------------- */

static void
set_tv_freq(struct i2c_client *c, int freq)
{
        u16 div = ((freq * 20) / 16);
        unsigned long give_up = jiffies + HZ;
        unsigned char buffer[2];

        if (debug)
                printk(KERN_DEBUG "tuner: setting frequency %dMHz, divisor %x\n", freq / 16, div);

        /* Select high tuning current */
        buffer[0] = 0x29;
        buffer[1] = 0x3e;

        if (i2c_master_send(c, buffer, 2) != 2)
                printk("tuner: i2c i/o error 1\n");

        buffer[0] = 0x80 | ((div>>8) & 0x7f);
        buffer[1] = div & 0xff;

        if (i2c_master_send(c, buffer, 2) != 2)
                printk("tuner: i2c i/o error 2\n");

        while (!tuner_islocked(c) && time_before(jiffies, give_up))
                schedule();

        if (!tuner_islocked(c))
                printk(KERN_WARNING "tuner: failed to achieve PLL lock\n");

        /* Select low tuning current and engage AFC */
        buffer[0] = 0x29;
        buffer[1] = 0xb2;

        if (i2c_master_send(c, buffer, 2) != 2)
                printk("tuner: i2c i/o error 3\n");

        if (debug)
                printk(KERN_DEBUG "tuner: status %02x\n", tuner_getstatus(c));
}

/* ---------------------------------------------------------------------- */

static int
tuner_attach(struct i2c_adapter *adap, int addr, int kind)
{
        static unsigned char buffer[] = { 0x29, 0x32, 0x2a, 0, 0x2b, 0 };

        struct i2c_client *client;

        if (this_adap > 0)
                return -1;
        this_adap++;

        client_template.adapter = adap;
        client_template.addr = addr;

        client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
        if (client == NULL)
                return -ENOMEM;
        memcpy(client, &client_template, sizeof(struct i2c_client));

        printk("tuner: SAB3036 found, status %02x\n", tuner_getstatus(client));

        i2c_attach_client(client);

        if (i2c_master_send(client, buffer, 2) != 2)
                printk("tuner: i2c i/o error 1\n");
        if (i2c_master_send(client, buffer+2, 2) != 2)
                printk("tuner: i2c i/o error 2\n");
        if (i2c_master_send(client, buffer+4, 2) != 2)
                printk("tuner: i2c i/o error 3\n");
        return 0;
}

static int
tuner_detach(struct i2c_client *c)
{
        return 0;
}

static int
tuner_command(struct i2c_client *client, unsigned int cmd, void *arg)
{
        int *iarg = (int*)arg;

        switch (cmd)
        {
                case VIDIOCSFREQ:
                        set_tv_freq(client, *iarg);
                        break;

                default:
                        return -EINVAL;
        }
        return 0;
}

static int
tuner_probe(struct i2c_adapter *adap)
{
        this_adap = 0;
        if (adap->id == I2C_HW_B_LP)
                return i2c_probe(adap, &addr_data, tuner_attach);
        return 0;
}

/* ----------------------------------------------------------------------- */

static struct i2c_driver
i2c_driver_tuner =
{
        .driver = {
                .name   =       "sab3036",
        },
        .id             =       I2C_DRIVERID_SAB3036,
        .attach_adapter =       tuner_probe,
        .detach_client  =       tuner_detach,
        .command        =       tuner_command
};

static struct i2c_client client_template =
{
        .driver         = &i2c_driver_tuner,
        .name           = "SAB3036",
};

static int __init
tuner3036_init(void)
{
        return i2c_add_driver(&i2c_driver_tuner);
}

static void __exit
tuner3036_exit(void)
{
        i2c_del_driver(&i2c_driver_tuner);
}

MODULE_DESCRIPTION("SAB3036 tuner driver");
MODULE_AUTHOR("Philip Blundell <philb@gnu.org>");
MODULE_LICENSE("GPL");

module_param(debug, int, 0);
MODULE_PARM_DESC(debug,"Enable debugging output");

module_init(tuner3036_init);
module_exit(tuner3036_exit);