/*
 * tef6862.c Philips TEF6862 Car Radio Enhanced Selectivity Tuner
 * Copyright (c) 2009 Intel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-device.h>

#define DRIVER_NAME "tef6862"

#define FREQ_MUL 16000

#define TEF6862_LO_FREQ (875U * FREQ_MUL / 10)
#define TEF6862_HI_FREQ (108U * FREQ_MUL)

/* Write mode sub addresses */
#define WM_SUB_BANDWIDTH        0x0
#define WM_SUB_PLLM             0x1
#define WM_SUB_PLLL             0x2
#define WM_SUB_DAA              0x3
#define WM_SUB_AGC              0x4
#define WM_SUB_BAND             0x5
#define WM_SUB_CONTROL          0x6
#define WM_SUB_LEVEL            0x7
#define WM_SUB_IFCF             0x8
#define WM_SUB_IFCAP            0x9
#define WM_SUB_ACD              0xA
#define WM_SUB_TEST             0xF

/* Different modes of the MSA register */
#define MODE_BUFFER             0x0
#define MODE_PRESET             0x1
#define MODE_SEARCH             0x2
#define MODE_AF_UPDATE          0x3
#define MODE_JUMP               0x4
#define MODE_CHECK              0x5
#define MODE_LOAD               0x6
#define MODE_END                0x7
#define MODE_SHIFT              5

struct tef6862_state {
        struct v4l2_subdev sd;
        unsigned long freq;
};

static inline struct tef6862_state *to_state(struct v4l2_subdev *sd)
{
        return container_of(sd, struct tef6862_state, sd);
}

static u16 tef6862_sigstr(struct i2c_client *client)
{
        u8 buf[4];
        int err = i2c_master_recv(client, buf, sizeof(buf));
        if (err == sizeof(buf))
                return buf[3] << 8;
        return 0;
}

static int tef6862_g_tuner(struct v4l2_subdev *sd, struct v4l2_tuner *v)
{
        if (v->index > 0)
                return -EINVAL;

        /* only support FM for now */
        strlcpy(v->name, "FM", sizeof(v->name));
        v->type = V4L2_TUNER_RADIO;
        v->rangelow = TEF6862_LO_FREQ;
        v->rangehigh = TEF6862_HI_FREQ;
        v->rxsubchans = V4L2_TUNER_SUB_MONO;
        v->capability = V4L2_TUNER_CAP_LOW;
        v->audmode = V4L2_TUNER_MODE_STEREO;
        v->signal = tef6862_sigstr(v4l2_get_subdevdata(sd));

        return 0;
}

static int tef6862_s_tuner(struct v4l2_subdev *sd, const struct v4l2_tuner *v)
{
        return v->index ? -EINVAL : 0;
}

static int tef6862_s_frequency(struct v4l2_subdev *sd, const struct v4l2_frequency *f)
{
        struct tef6862_state *state = to_state(sd);
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        unsigned freq = f->frequency;
        u16 pll;
        u8 i2cmsg[3];
        int err;

        if (f->tuner != 0)
                return -EINVAL;

        clamp(freq, TEF6862_LO_FREQ, TEF6862_HI_FREQ);
        pll = 1964 + ((freq - TEF6862_LO_FREQ) * 20) / FREQ_MUL;
        i2cmsg[0] = (MODE_PRESET << MODE_SHIFT) | WM_SUB_PLLM;
        i2cmsg[1] = (pll >> 8) & 0xff;
        i2cmsg[2] = pll & 0xff;

        err = i2c_master_send(client, i2cmsg, sizeof(i2cmsg));
        if (err != sizeof(i2cmsg))
                return err < 0 ? err : -EIO;

        state->freq = freq;
        return 0;
}

static int tef6862_g_frequency(struct v4l2_subdev *sd, struct v4l2_frequency *f)
{
        struct tef6862_state *state = to_state(sd);

        if (f->tuner != 0)
                return -EINVAL;
        f->type = V4L2_TUNER_RADIO;
        f->frequency = state->freq;
        return 0;
}

static const struct v4l2_subdev_tuner_ops tef6862_tuner_ops = {
        .g_tuner = tef6862_g_tuner,
        .s_tuner = tef6862_s_tuner,
        .s_frequency = tef6862_s_frequency,
        .g_frequency = tef6862_g_frequency,
};

static const struct v4l2_subdev_ops tef6862_ops = {
        .tuner = &tef6862_tuner_ops,
};

/*
 * Generic i2c probe
 * concerning the addresses: i2c wants 7 bit (without the r/w bit), so '>>1'
 */

static int tef6862_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
{
        struct tef6862_state *state;
        struct v4l2_subdev *sd;

        /* Check if the adapter supports the needed features */
        if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                return -EIO;

        v4l_info(client, "chip found @ 0x%02x (%s)\n",
                        client->addr << 1, client->adapter->name);

        state = kzalloc(sizeof(struct tef6862_state), GFP_KERNEL);
        if (state == NULL)
                return -ENOMEM;
        state->freq = TEF6862_LO_FREQ;

        sd = &state->sd;
        v4l2_i2c_subdev_init(sd, client, &tef6862_ops);

        return 0;
}

static int tef6862_remove(struct i2c_client *client)
{
        struct v4l2_subdev *sd = i2c_get_clientdata(client);

        v4l2_device_unregister_subdev(sd);
        kfree(to_state(sd));
        return 0;
}

static const struct i2c_device_id tef6862_id[] = {
        {DRIVER_NAME, 0},
        {},
};

MODULE_DEVICE_TABLE(i2c, tef6862_id);

static struct i2c_driver tef6862_driver = {
        .driver = {
                .owner  = THIS_MODULE,
                .name   = DRIVER_NAME,
        },
        .probe          = tef6862_probe,
        .remove         = tef6862_remove,
        .id_table       = tef6862_id,
};

module_i2c_driver(tef6862_driver);

MODULE_DESCRIPTION("TEF6862 Car Radio Enhanced Selectivity Tuner");
MODULE_AUTHOR("Mocean Laboratories");
MODULE_LICENSE("GPL v2");