/*
        TDA8261 8PSK/QPSK tuner driver
        Copyright (C) Manu Abraham (abraham.manu@gmail.com)

        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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/


#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "dvb_frontend.h"
#include "tda8261.h"

struct tda8261_state {
        struct dvb_frontend             *fe;
        struct i2c_adapter              *i2c;
        const struct tda8261_config     *config;

        /* state cache */
        u32 frequency;
        u32 bandwidth;
};

static int tda8261_read(struct tda8261_state *state, u8 *buf)
{
        const struct tda8261_config *config = state->config;
        int err = 0;
        struct i2c_msg msg = { .addr    = config->addr, .flags = I2C_M_RD,.buf = buf,  .len = 1 };

        if ((err = i2c_transfer(state->i2c, &msg, 1)) != 1)
                pr_err("%s: read error, err=%d\n", __func__, err);

        return err;
}

static int tda8261_write(struct tda8261_state *state, u8 *buf)
{
        const struct tda8261_config *config = state->config;
        int err = 0;
        struct i2c_msg msg = { .addr = config->addr, .flags = 0, .buf = buf, .len = 4 };

        if ((err = i2c_transfer(state->i2c, &msg, 1)) != 1)
                pr_err("%s: write error, err=%d\n", __func__, err);

        return err;
}

static int tda8261_get_status(struct dvb_frontend *fe, u32 *status)
{
        struct tda8261_state *state = fe->tuner_priv;
        u8 result = 0;
        int err = 0;

        *status = 0;

        if ((err = tda8261_read(state, &result)) < 0) {
                pr_err("%s: I/O Error\n", __func__);
                return err;
        }
        if ((result >> 6) & 0x01) {
                pr_debug("%s: Tuner Phase Locked\n", __func__);
                *status = 1;
        }

        return err;
}

static const u32 div_tab[] = { 2000, 1000,  500,  250,  125 }; /* kHz */
static const u8  ref_div[] = { 0x00, 0x01, 0x02, 0x05, 0x07 };

static int tda8261_get_frequency(struct dvb_frontend *fe, u32 *frequency)
{
        struct tda8261_state *state = fe->tuner_priv;

        *frequency = state->frequency;

        return 0;
}

static int tda8261_set_params(struct dvb_frontend *fe)
{
        struct dtv_frontend_properties *c = &fe->dtv_property_cache;
        struct tda8261_state *state = fe->tuner_priv;
        const struct tda8261_config *config = state->config;
        u32 frequency, N, status = 0;
        u8 buf[4];
        int err = 0;

        /*
         * N = Max VCO Frequency / Channel Spacing
         * Max VCO Frequency = VCO frequency + (channel spacing - 1)
         * (to account for half channel spacing on either side)
         */
        frequency = c->frequency;
        if ((frequency < 950000) || (frequency > 2150000)) {
                pr_warn("%s: Frequency beyond limits, frequency=%d\n",
                        __func__, frequency);
                return -EINVAL;
        }
        N = (frequency + (div_tab[config->step_size] - 1)) / div_tab[config->step_size];
        pr_debug("%s: Step size=%d, Divider=%d, PG=0x%02x (%d)\n",
                __func__, config->step_size, div_tab[config->step_size], N, N);

        buf[0] = (N >> 8) & 0xff;
        buf[1] = N & 0xff;
        buf[2] = (0x01 << 7) | ((ref_div[config->step_size] & 0x07) << 1);

        if (frequency < 1450000)
                buf[3] = 0x00;
        else if (frequency < 2000000)
                buf[3] = 0x40;
        else if (frequency < 2150000)
                buf[3] = 0x80;

        /* Set params */
        err = tda8261_write(state, buf);
        if (err < 0) {
                pr_err("%s: I/O Error\n", __func__);
                return err;
        }
        /* sleep for some time */
        pr_debug("%s: Waiting to Phase LOCK\n", __func__);
        msleep(20);
        /* check status */
        if ((err = tda8261_get_status(fe, &status)) < 0) {
                pr_err("%s: I/O Error\n", __func__);
                return err;
        }
        if (status == 1) {
                pr_debug("%s: Tuner Phase locked: status=%d\n", __func__,
                         status);
                state->frequency = frequency; /* cache successful state */
        } else {
                pr_debug("%s: No Phase lock: status=%d\n", __func__, status);
        }

        return 0;
}

static void tda8261_release(struct dvb_frontend *fe)
{
        struct tda8261_state *state = fe->tuner_priv;

        fe->tuner_priv = NULL;
        kfree(state);
}

static const struct dvb_tuner_ops tda8261_ops = {

        .info = {
                .name           = "TDA8261",
                .frequency_min  =  950000,
                .frequency_max  = 2150000,
                .frequency_step = 0
        },

        .set_params     = tda8261_set_params,
        .get_frequency  = tda8261_get_frequency,
        .get_status     = tda8261_get_status,
        .release        = tda8261_release
};

struct dvb_frontend *tda8261_attach(struct dvb_frontend *fe,
                                    const struct tda8261_config *config,
                                    struct i2c_adapter *i2c)
{
        struct tda8261_state *state = NULL;

        if ((state = kzalloc(sizeof (struct tda8261_state), GFP_KERNEL)) == NULL)
                goto exit;

        state->config           = config;
        state->i2c              = i2c;
        state->fe               = fe;
        fe->tuner_priv          = state;
        fe->ops.tuner_ops       = tda8261_ops;

        fe->ops.tuner_ops.info.frequency_step = div_tab[config->step_size];

        pr_info("%s: Attaching TDA8261 8PSK/QPSK tuner\n", __func__);

        return fe;

exit:
        kfree(state);
        return NULL;
}

EXPORT_SYMBOL(tda8261_attach);

MODULE_AUTHOR("Manu Abraham");
MODULE_DESCRIPTION("TDA8261 8PSK/QPSK Tuner");
MODULE_LICENSE("GPL");