// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * stv6110.c
 *
 * Driver for ST STV6110 satellite tuner IC.
 *
 * Copyright (C) 2009 NetUP Inc.
 * Copyright (C) 2009 Igor M. Liplianin <liplianin@netup.ru>
 */

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

#include <linux/types.h>

#include "stv6110.h"

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

static int debug;

struct stv6110_priv {
        int i2c_address;
        struct i2c_adapter *i2c;

        u32 mclk;
        u8 clk_div;
        u8 gain;
        u8 regs[8];
};

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

static s32 abssub(s32 a, s32 b)
{
        if (a > b)
                return a - b;
        else
                return b - a;
};

static void stv6110_release(struct dvb_frontend *fe)
{
        kfree(fe->tuner_priv);
        fe->tuner_priv = NULL;
}

static int stv6110_write_regs(struct dvb_frontend *fe, u8 buf[],
                                                        int start, int len)
{
        struct stv6110_priv *priv = fe->tuner_priv;
        int rc;
        u8 cmdbuf[MAX_XFER_SIZE];
        struct i2c_msg msg = {
                .addr   = priv->i2c_address,
                .flags  = 0,
                .buf    = cmdbuf,
                .len    = len + 1
        };

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

        if (1 + len > sizeof(cmdbuf)) {
                printk(KERN_WARNING
                       "%s: i2c wr: len=%d is too big!\n",
                       KBUILD_MODNAME, len);
                return -EINVAL;
        }

        if (start + len > 8)
                return -EINVAL;

        memcpy(&cmdbuf[1], buf, len);
        cmdbuf[0] = start;

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);

        rc = i2c_transfer(priv->i2c, &msg, 1);
        if (rc != 1)
                dprintk("%s: i2c error\n", __func__);

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);

        return 0;
}

static int stv6110_read_regs(struct dvb_frontend *fe, u8 regs[],
                                                        int start, int len)
{
        struct stv6110_priv *priv = fe->tuner_priv;
        int rc;
        u8 reg[] = { start };
        struct i2c_msg msg[] = {
                {
                        .addr   = priv->i2c_address,
                        .flags  = 0,
                        .buf    = reg,
                        .len    = 1,
                }, {
                        .addr   = priv->i2c_address,
                        .flags  = I2C_M_RD,
                        .buf    = regs,
                        .len    = len,
                },
        };

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);

        rc = i2c_transfer(priv->i2c, msg, 2);
        if (rc != 2)
                dprintk("%s: i2c error\n", __func__);

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);

        memcpy(&priv->regs[start], regs, len);

        return 0;
}

static int stv6110_read_reg(struct dvb_frontend *fe, int start)
{
        u8 buf[] = { 0 };
        stv6110_read_regs(fe, buf, start, 1);

        return buf[0];
}

static int stv6110_sleep(struct dvb_frontend *fe)
{
        u8 reg[] = { 0 };
        stv6110_write_regs(fe, reg, 0, 1);

        return 0;
}

static u32 carrier_width(u32 symbol_rate, enum fe_rolloff rolloff)
{
        u32 rlf;

        switch (rolloff) {
        case ROLLOFF_20:
                rlf = 20;
                break;
        case ROLLOFF_25:
                rlf = 25;
                break;
        default:
                rlf = 35;
                break;
        }

        return symbol_rate  + ((symbol_rate * rlf) / 100);
}

static int stv6110_set_bandwidth(struct dvb_frontend *fe, u32 bandwidth)
{
        struct stv6110_priv *priv = fe->tuner_priv;
        u8 r8, ret = 0x04;
        int i;

        if ((bandwidth / 2) > 36000000) /*BW/2 max=31+5=36 mhz for r8=31*/
                r8 = 31;
        else if ((bandwidth / 2) < 5000000) /* BW/2 min=5Mhz for F=0 */
                r8 = 0;
        else /*if 5 < BW/2 < 36*/
                r8 = (bandwidth / 2) / 1000000 - 5;

        /* ctrl3, RCCLKOFF = 0 Activate the calibration Clock */
        /* ctrl3, CF = r8 Set the LPF value */
        priv->regs[RSTV6110_CTRL3] &= ~((1 << 6) | 0x1f);
        priv->regs[RSTV6110_CTRL3] |= (r8 & 0x1f);
        stv6110_write_regs(fe, &priv->regs[RSTV6110_CTRL3], RSTV6110_CTRL3, 1);
        /* stat1, CALRCSTRT = 1 Start LPF auto calibration*/
        priv->regs[RSTV6110_STAT1] |= 0x02;
        stv6110_write_regs(fe, &priv->regs[RSTV6110_STAT1], RSTV6110_STAT1, 1);

        i = 0;
        /* Wait for CALRCSTRT == 0 */
        while ((i < 10) && (ret != 0)) {
                ret = ((stv6110_read_reg(fe, RSTV6110_STAT1)) & 0x02);
                mdelay(1);      /* wait for LPF auto calibration */
                i++;
        }

        /* RCCLKOFF = 1 calibration done, deactivate the calibration Clock */
        priv->regs[RSTV6110_CTRL3] |= (1 << 6);
        stv6110_write_regs(fe, &priv->regs[RSTV6110_CTRL3], RSTV6110_CTRL3, 1);
        return 0;
}

static int stv6110_init(struct dvb_frontend *fe)
{
        struct stv6110_priv *priv = fe->tuner_priv;
        u8 buf0[] = { 0x07, 0x11, 0xdc, 0x85, 0x17, 0x01, 0xe6, 0x1e };

        memcpy(priv->regs, buf0, 8);
        /* K = (Reference / 1000000) - 16 */
        priv->regs[RSTV6110_CTRL1] &= ~(0x1f << 3);
        priv->regs[RSTV6110_CTRL1] |=
                                ((((priv->mclk / 1000000) - 16) & 0x1f) << 3);

        /* divisor value for the output clock */
        priv->regs[RSTV6110_CTRL2] &= ~0xc0;
        priv->regs[RSTV6110_CTRL2] |= (priv->clk_div << 6);

        stv6110_write_regs(fe, &priv->regs[RSTV6110_CTRL1], RSTV6110_CTRL1, 8);
        msleep(1);
        stv6110_set_bandwidth(fe, 72000000);

        return 0;
}

static int stv6110_get_frequency(struct dvb_frontend *fe, u32 *frequency)
{
        struct stv6110_priv *priv = fe->tuner_priv;
        u32 nbsteps, divider, psd2, freq;
        u8 regs[] = { 0, 0, 0, 0, 0, 0, 0, 0 };

        stv6110_read_regs(fe, regs, 0, 8);
        /*N*/
        divider = (priv->regs[RSTV6110_TUNING2] & 0x0f) << 8;
        divider += priv->regs[RSTV6110_TUNING1];

        /*R*/
        nbsteps  = (priv->regs[RSTV6110_TUNING2] >> 6) & 3;
        /*p*/
        psd2  = (priv->regs[RSTV6110_TUNING2] >> 4) & 1;

        freq = divider * (priv->mclk / 1000);
        freq /= (1 << (nbsteps + psd2));
        freq /= 4;

        *frequency = freq;

        return 0;
}

static int stv6110_set_frequency(struct dvb_frontend *fe, u32 frequency)
{
        struct stv6110_priv *priv = fe->tuner_priv;
        u8 ret = 0x04;
        u32 divider, ref, p, presc, i, result_freq, vco_freq;
        s32 p_calc, p_calc_opt = 1000, r_div, r_div_opt = 0, p_val;

        dprintk("%s, freq=%d kHz, mclk=%d Hz\n", __func__,
                                                frequency, priv->mclk);

        /* K = (Reference / 1000000) - 16 */
        priv->regs[RSTV6110_CTRL1] &= ~(0x1f << 3);
        priv->regs[RSTV6110_CTRL1] |=
                                ((((priv->mclk / 1000000) - 16) & 0x1f) << 3);

        /* BB_GAIN = db/2 */
        priv->regs[RSTV6110_CTRL2] &= ~0x0f;
        priv->regs[RSTV6110_CTRL2] |= (priv->gain & 0x0f);

        if (frequency <= 1023000) {
                p = 1;
                presc = 0;
        } else if (frequency <= 1300000) {
                p = 1;
                presc = 1;
        } else if (frequency <= 2046000) {
                p = 0;
                presc = 0;
        } else {
                p = 0;
                presc = 1;
        }
        /* DIV4SEL = p*/
        priv->regs[RSTV6110_TUNING2] &= ~(1 << 4);
        priv->regs[RSTV6110_TUNING2] |= (p << 4);

        /* PRESC32ON = presc */
        priv->regs[RSTV6110_TUNING2] &= ~(1 << 5);
        priv->regs[RSTV6110_TUNING2] |= (presc << 5);

        p_val = (int)(1 << (p + 1)) * 10;/* P = 2 or P = 4 */
        for (r_div = 0; r_div <= 3; r_div++) {
                p_calc = (priv->mclk / 100000);
                p_calc /= (1 << (r_div + 1));
                if ((abssub(p_calc, p_val)) < (abssub(p_calc_opt, p_val)))
                        r_div_opt = r_div;

                p_calc_opt = (priv->mclk / 100000);
                p_calc_opt /= (1 << (r_div_opt + 1));
        }

        ref = priv->mclk / ((1 << (r_div_opt + 1))  * (1 << (p + 1)));
        divider = (((frequency * 1000) + (ref >> 1)) / ref);

        /* RDIV = r_div_opt */
        priv->regs[RSTV6110_TUNING2] &= ~(3 << 6);
        priv->regs[RSTV6110_TUNING2] |= (((r_div_opt) & 3) << 6);

        /* NDIV_MSB = MSB(divider) */
        priv->regs[RSTV6110_TUNING2] &= ~0x0f;
        priv->regs[RSTV6110_TUNING2] |= (((divider) >> 8) & 0x0f);

        /* NDIV_LSB, LSB(divider) */
        priv->regs[RSTV6110_TUNING1] = (divider & 0xff);

        /* CALVCOSTRT = 1 VCO Auto Calibration */
        priv->regs[RSTV6110_STAT1] |= 0x04;
        stv6110_write_regs(fe, &priv->regs[RSTV6110_CTRL1],
                                                RSTV6110_CTRL1, 8);

        i = 0;
        /* Wait for CALVCOSTRT == 0 */
        while ((i < 10) && (ret != 0)) {
                ret = ((stv6110_read_reg(fe, RSTV6110_STAT1)) & 0x04);
                msleep(1); /* wait for VCO auto calibration */
                i++;
        }

        ret = stv6110_read_reg(fe, RSTV6110_STAT1);
        stv6110_get_frequency(fe, &result_freq);

        vco_freq = divider * ((priv->mclk / 1000) / ((1 << (r_div_opt + 1))));
        dprintk("%s, stat1=%x, lo_freq=%d kHz, vco_frec=%d kHz\n", __func__,
                                                ret, result_freq, vco_freq);

        return 0;
}

static int stv6110_set_params(struct dvb_frontend *fe)
{
        struct dtv_frontend_properties *c = &fe->dtv_property_cache;
        u32 bandwidth = carrier_width(c->symbol_rate, c->rolloff);

        stv6110_set_frequency(fe, c->frequency);
        stv6110_set_bandwidth(fe, bandwidth);

        return 0;
}

static int stv6110_get_bandwidth(struct dvb_frontend *fe, u32 *bandwidth)
{
        struct stv6110_priv *priv = fe->tuner_priv;
        u8 r8 = 0;
        u8 regs[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
        stv6110_read_regs(fe, regs, 0, 8);

        /* CF */
        r8 = priv->regs[RSTV6110_CTRL3] & 0x1f;
        *bandwidth = (r8 + 5) * 2000000;/* x2 for ZIF tuner BW/2 = F+5 Mhz */

        return 0;
}

static const struct dvb_tuner_ops stv6110_tuner_ops = {
        .info = {
                .name = "ST STV6110",
                .frequency_min_hz  =  950 * MHz,
                .frequency_max_hz  = 2150 * MHz,
                .frequency_step_hz =    1 * MHz,
        },
        .init = stv6110_init,
        .release = stv6110_release,
        .sleep = stv6110_sleep,
        .set_params = stv6110_set_params,
        .get_frequency = stv6110_get_frequency,
        .set_frequency = stv6110_set_frequency,
        .get_bandwidth = stv6110_get_bandwidth,
        .set_bandwidth = stv6110_set_bandwidth,

};

struct dvb_frontend *stv6110_attach(struct dvb_frontend *fe,
                                        const struct stv6110_config *config,
                                        struct i2c_adapter *i2c)
{
        struct stv6110_priv *priv = NULL;
        u8 reg0[] = { 0x00, 0x07, 0x11, 0xdc, 0x85, 0x17, 0x01, 0xe6, 0x1e };

        struct i2c_msg msg[] = {
                {
                        .addr = config->i2c_address,
                        .flags = 0,
                        .buf = reg0,
                        .len = 9
                }
        };
        int ret;

        /* divisor value for the output clock */
        reg0[2] &= ~0xc0;
        reg0[2] |= (config->clk_div << 6);

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);

        ret = i2c_transfer(i2c, msg, 1);

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);

        if (ret != 1)
                return NULL;

        priv = kzalloc_obj(struct stv6110_priv);
        if (priv == NULL)
                return NULL;

        priv->i2c_address = config->i2c_address;
        priv->i2c = i2c;
        priv->mclk = config->mclk;
        priv->clk_div = config->clk_div;
        priv->gain = config->gain;

        memcpy(&priv->regs, &reg0[1], 8);

        memcpy(&fe->ops.tuner_ops, &stv6110_tuner_ops,
                                sizeof(struct dvb_tuner_ops));
        fe->tuner_priv = priv;
        printk(KERN_INFO "STV6110 attached on addr=%x!\n", priv->i2c_address);

        return fe;
}
EXPORT_SYMBOL_GPL(stv6110_attach);

module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Turn on/off frontend debugging (default:off).");

MODULE_DESCRIPTION("ST STV6110 driver");
MODULE_AUTHOR("Igor M. Liplianin");
MODULE_LICENSE("GPL");