/*
 *  Driver for Zarlink ZL10039 DVB-S tuner
 *
 *  Copyright 2007 Jan D. Louw <jd.louw@mweb.co.za>
 *
 *  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.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/dvb/frontend.h>

#include <media/dvb_frontend.h>
#include "zl10039.h"

static int debug;

/* Max transfer size done by I2C transfer functions */
#define MAX_XFER_SIZE  64

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

enum zl10039_model_id {
        ID_ZL10039 = 1
};

struct zl10039_state {
        struct i2c_adapter *i2c;
        u8 i2c_addr;
        u8 id;
};

enum zl10039_reg_addr {
        PLL0 = 0,
        PLL1,
        PLL2,
        PLL3,
        RFFE,
        BASE0,
        BASE1,
        BASE2,
        LO0,
        LO1,
        LO2,
        LO3,
        LO4,
        LO5,
        LO6,
        GENERAL
};

static int zl10039_read(const struct zl10039_state *state,
                        const enum zl10039_reg_addr reg, u8 *buf,
                        const size_t count)
{
        u8 regbuf[] = { reg };
        struct i2c_msg msg[] = {
                {/* Write register address */
                        .addr = state->i2c_addr,
                        .flags = 0,
                        .buf = regbuf,
                        .len = 1,
                }, {/* Read count bytes */
                        .addr = state->i2c_addr,
                        .flags = I2C_M_RD,
                        .buf = buf,
                        .len = count,
                },
        };

        dprintk("%s\n", __func__);

        if (i2c_transfer(state->i2c, msg, 2) != 2) {
                dprintk("%s: i2c read error\n", __func__);
                return -EREMOTEIO;
        }

        return 0; /* Success */
}

static int zl10039_write(struct zl10039_state *state,
                        const enum zl10039_reg_addr reg, const u8 *src,
                        const size_t count)
{
        u8 buf[MAX_XFER_SIZE];
        struct i2c_msg msg = {
                .addr = state->i2c_addr,
                .flags = 0,
                .buf = buf,
                .len = count + 1,
        };

        if (1 + count > sizeof(buf)) {
                printk(KERN_WARNING
                       "%s: i2c wr reg=%04x: len=%zu is too big!\n",
                       KBUILD_MODNAME, reg, count);
                return -EINVAL;
        }

        dprintk("%s\n", __func__);
        /* Write register address and data in one go */
        buf[0] = reg;
        memcpy(&buf[1], src, count);
        if (i2c_transfer(state->i2c, &msg, 1) != 1) {
                dprintk("%s: i2c write error\n", __func__);
                return -EREMOTEIO;
        }

        return 0; /* Success */
}

static inline int zl10039_readreg(struct zl10039_state *state,
                                const enum zl10039_reg_addr reg, u8 *val)
{
        return zl10039_read(state, reg, val, 1);
}

static inline int zl10039_writereg(struct zl10039_state *state,
                                const enum zl10039_reg_addr reg,
                                const u8 val)
{
        const u8 tmp = val; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */

        return zl10039_write(state, reg, &tmp, 1);
}

static int zl10039_init(struct dvb_frontend *fe)
{
        struct zl10039_state *state = fe->tuner_priv;
        int ret;

        dprintk("%s\n", __func__);
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);
        /* Reset logic */
        ret = zl10039_writereg(state, GENERAL, 0x40);
        if (ret < 0) {
                dprintk("Note: i2c write error normal when resetting the tuner\n");
        }
        /* Wake up */
        ret = zl10039_writereg(state, GENERAL, 0x01);
        if (ret < 0) {
                dprintk("Tuner power up failed\n");
                return ret;
        }
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);

        return 0;
}

static int zl10039_sleep(struct dvb_frontend *fe)
{
        struct zl10039_state *state = fe->tuner_priv;
        int ret;

        dprintk("%s\n", __func__);
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);
        ret = zl10039_writereg(state, GENERAL, 0x80);
        if (ret < 0) {
                dprintk("Tuner sleep failed\n");
                return ret;
        }
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);

        return 0;
}

static int zl10039_set_params(struct dvb_frontend *fe)
{
        struct dtv_frontend_properties *c = &fe->dtv_property_cache;
        struct zl10039_state *state = fe->tuner_priv;
        u8 buf[6];
        u8 bf;
        u32 fbw;
        u32 div;
        int ret;

        dprintk("%s\n", __func__);
        dprintk("Set frequency = %d, symbol rate = %d\n",
                        c->frequency, c->symbol_rate);

        /* Assumed 10.111 MHz crystal oscillator */
        /* Cancelled num/den 80 to prevent overflow */
        div = (c->frequency * 1000) / 126387;
        fbw = (c->symbol_rate * 27) / 32000;
        /* Cancelled num/den 10 to prevent overflow */
        bf = ((fbw * 5088) / 1011100) - 1;

        /*PLL divider*/
        buf[0] = (div >> 8) & 0x7f;
        buf[1] = (div >> 0) & 0xff;
        /*Reference divider*/
        /* Select reference ratio of 80 */
        buf[2] = 0x1D;
        /*PLL test modes*/
        buf[3] = 0x40;
        /*RF Control register*/
        buf[4] = 0x6E; /* Bypass enable */
        /*Baseband filter cutoff */
        buf[5] = bf;

        /* Open i2c gate */
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);
        /* BR = 10, Enable filter adjustment */
        ret = zl10039_writereg(state, BASE1, 0x0A);
        if (ret < 0)
                goto error;
        /* Write new config values */
        ret = zl10039_write(state, PLL0, buf, sizeof(buf));
        if (ret < 0)
                goto error;
        /* BR = 10, Disable filter adjustment */
        ret = zl10039_writereg(state, BASE1, 0x6A);
        if (ret < 0)
                goto error;

        /* Close i2c gate */
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);
        return 0;
error:
        dprintk("Error setting tuner\n");
        return ret;
}

static void zl10039_release(struct dvb_frontend *fe)
{
        struct zl10039_state *state = fe->tuner_priv;

        dprintk("%s\n", __func__);
        kfree(state);
        fe->tuner_priv = NULL;
}

static const struct dvb_tuner_ops zl10039_ops = {
        .release = zl10039_release,
        .init = zl10039_init,
        .sleep = zl10039_sleep,
        .set_params = zl10039_set_params,
};

struct dvb_frontend *zl10039_attach(struct dvb_frontend *fe,
                u8 i2c_addr, struct i2c_adapter *i2c)
{
        struct zl10039_state *state = NULL;

        dprintk("%s\n", __func__);
        state = kmalloc(sizeof(struct zl10039_state), GFP_KERNEL);
        if (state == NULL)
                goto error;

        state->i2c = i2c;
        state->i2c_addr = i2c_addr;

        /* Open i2c gate */
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);
        /* check if this is a valid tuner */
        if (zl10039_readreg(state, GENERAL, &state->id) < 0) {
                /* Close i2c gate */
                if (fe->ops.i2c_gate_ctrl)
                        fe->ops.i2c_gate_ctrl(fe, 0);
                goto error;
        }
        /* Close i2c gate */
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);

        state->id = state->id & 0x0f;
        switch (state->id) {
        case ID_ZL10039:
                strcpy(fe->ops.tuner_ops.info.name,
                        "Zarlink ZL10039 DVB-S tuner");
                break;
        default:
                dprintk("Chip ID=%x does not match a known type\n", state->id);
                goto error;
        }

        memcpy(&fe->ops.tuner_ops, &zl10039_ops, sizeof(struct dvb_tuner_ops));
        fe->tuner_priv = state;
        dprintk("Tuner attached @ i2c address 0x%02x\n", i2c_addr);
        return fe;
error:
        kfree(state);
        return NULL;
}
EXPORT_SYMBOL(zl10039_attach);

module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Turn on/off frontend debugging (default:off).");
MODULE_DESCRIPTION("Zarlink ZL10039 DVB-S tuner driver");
MODULE_AUTHOR("Jan D. Louw <jd.louw@mweb.co.za>");
MODULE_LICENSE("GPL");