// SPDX-License-Identifier: GPL-2.0-or-later
/*
    Conexant 22702 DVB OFDM demodulator driver

    based on:
        Alps TDMB7 DVB OFDM demodulator driver

    Copyright (C) 2001-2002 Convergence Integrated Media GmbH
          Holger Waechtler <holger@convergence.de>

    Copyright (C) 2004 Steven Toth <stoth@linuxtv.org>


*/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <media/dvb_frontend.h>
#include "cx22702.h"

struct cx22702_state {

        struct i2c_adapter *i2c;

        /* configuration settings */
        const struct cx22702_config *config;

        struct dvb_frontend frontend;

        /* previous uncorrected block counter */
        u8 prevUCBlocks;
};

static int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Enable verbose debug messages");

#define dprintk if (debug) printk

/* Register values to initialise the demod */
static const u8 init_tab[] = {
        0x00, 0x00, /* Stop acquisition */
        0x0B, 0x06,
        0x09, 0x01,
        0x0D, 0x41,
        0x16, 0x32,
        0x20, 0x0A,
        0x21, 0x17,
        0x24, 0x3e,
        0x26, 0xff,
        0x27, 0x10,
        0x28, 0x00,
        0x29, 0x00,
        0x2a, 0x10,
        0x2b, 0x00,
        0x2c, 0x10,
        0x2d, 0x00,
        0x48, 0xd4,
        0x49, 0x56,
        0x6b, 0x1e,
        0xc8, 0x02,
        0xf9, 0x00,
        0xfa, 0x00,
        0xfb, 0x00,
        0xfc, 0x00,
        0xfd, 0x00,
};

static int cx22702_writereg(struct cx22702_state *state, u8 reg, u8 data)
{
        int ret;
        u8 buf[] = { reg, data };
        struct i2c_msg msg = {
                .addr = state->config->demod_address, .flags = 0,
                        .buf = buf, .len = 2 };

        ret = i2c_transfer(state->i2c, &msg, 1);

        if (unlikely(ret != 1)) {
                printk(KERN_ERR
                        "%s: error (reg == 0x%02x, val == 0x%02x, ret == %i)\n",
                        __func__, reg, data, ret);
                return -1;
        }

        return 0;
}

static u8 cx22702_readreg(struct cx22702_state *state, u8 reg)
{
        int ret;
        u8 data;

        struct i2c_msg msg[] = {
                { .addr = state->config->demod_address, .flags = 0,
                        .buf = &reg, .len = 1 },
                { .addr = state->config->demod_address, .flags = I2C_M_RD,
                        .buf = &data, .len = 1 } };

        ret = i2c_transfer(state->i2c, msg, 2);

        if (unlikely(ret != 2)) {
                printk(KERN_ERR "%s: error (reg == 0x%02x, ret == %i)\n",
                        __func__, reg, ret);
                return 0;
        }

        return data;
}

static int cx22702_set_inversion(struct cx22702_state *state, int inversion)
{
        u8 val;

        val = cx22702_readreg(state, 0x0C);
        switch (inversion) {
        case INVERSION_AUTO:
                return -EOPNOTSUPP;
        case INVERSION_ON:
                val |= 0x01;
                break;
        case INVERSION_OFF:
                val &= 0xfe;
                break;
        default:
                return -EINVAL;
        }
        return cx22702_writereg(state, 0x0C, val);
}

/* Retrieve the demod settings */
static int cx22702_get_tps(struct cx22702_state *state,
                           struct dtv_frontend_properties *p)
{
        u8 val;

        /* Make sure the TPS regs are valid */
        if (!(cx22702_readreg(state, 0x0A) & 0x20))
                return -EAGAIN;

        val = cx22702_readreg(state, 0x01);
        switch ((val & 0x18) >> 3) {
        case 0:
                p->modulation = QPSK;
                break;
        case 1:
                p->modulation = QAM_16;
                break;
        case 2:
                p->modulation = QAM_64;
                break;
        }
        switch (val & 0x07) {
        case 0:
                p->hierarchy = HIERARCHY_NONE;
                break;
        case 1:
                p->hierarchy = HIERARCHY_1;
                break;
        case 2:
                p->hierarchy = HIERARCHY_2;
                break;
        case 3:
                p->hierarchy = HIERARCHY_4;
                break;
        }


        val = cx22702_readreg(state, 0x02);
        switch ((val & 0x38) >> 3) {
        case 0:
                p->code_rate_HP = FEC_1_2;
                break;
        case 1:
                p->code_rate_HP = FEC_2_3;
                break;
        case 2:
                p->code_rate_HP = FEC_3_4;
                break;
        case 3:
                p->code_rate_HP = FEC_5_6;
                break;
        case 4:
                p->code_rate_HP = FEC_7_8;
                break;
        }
        switch (val & 0x07) {
        case 0:
                p->code_rate_LP = FEC_1_2;
                break;
        case 1:
                p->code_rate_LP = FEC_2_3;
                break;
        case 2:
                p->code_rate_LP = FEC_3_4;
                break;
        case 3:
                p->code_rate_LP = FEC_5_6;
                break;
        case 4:
                p->code_rate_LP = FEC_7_8;
                break;
        }

        val = cx22702_readreg(state, 0x03);
        switch ((val & 0x0c) >> 2) {
        case 0:
                p->guard_interval = GUARD_INTERVAL_1_32;
                break;
        case 1:
                p->guard_interval = GUARD_INTERVAL_1_16;
                break;
        case 2:
                p->guard_interval = GUARD_INTERVAL_1_8;
                break;
        case 3:
                p->guard_interval = GUARD_INTERVAL_1_4;
                break;
        }
        switch (val & 0x03) {
        case 0:
                p->transmission_mode = TRANSMISSION_MODE_2K;
                break;
        case 1:
                p->transmission_mode = TRANSMISSION_MODE_8K;
                break;
        }

        return 0;
}

static int cx22702_i2c_gate_ctrl(struct dvb_frontend *fe, int enable)
{
        struct cx22702_state *state = fe->demodulator_priv;
        u8 val;

        dprintk("%s(%d)\n", __func__, enable);
        val = cx22702_readreg(state, 0x0D);
        if (enable)
                val &= 0xfe;
        else
                val |= 0x01;
        return cx22702_writereg(state, 0x0D, val);
}

/* Talk to the demod, set the FEC, GUARD, QAM settings etc */
static int cx22702_set_tps(struct dvb_frontend *fe)
{
        struct dtv_frontend_properties *p = &fe->dtv_property_cache;
        u8 val;
        struct cx22702_state *state = fe->demodulator_priv;

        if (fe->ops.tuner_ops.set_params) {
                fe->ops.tuner_ops.set_params(fe);
                if (fe->ops.i2c_gate_ctrl)
                        fe->ops.i2c_gate_ctrl(fe, 0);
        }

        /* set inversion */
        cx22702_set_inversion(state, p->inversion);

        /* set bandwidth */
        val = cx22702_readreg(state, 0x0C) & 0xcf;
        switch (p->bandwidth_hz) {
        case 6000000:
                val |= 0x20;
                break;
        case 7000000:
                val |= 0x10;
                break;
        case 8000000:
                break;
        default:
                dprintk("%s: invalid bandwidth\n", __func__);
                return -EINVAL;
        }
        cx22702_writereg(state, 0x0C, val);

        p->code_rate_LP = FEC_AUTO; /* temp hack as manual not working */

        /* use auto configuration? */
        if ((p->hierarchy == HIERARCHY_AUTO) ||
           (p->modulation == QAM_AUTO) ||
           (p->code_rate_HP == FEC_AUTO) ||
           (p->code_rate_LP == FEC_AUTO) ||
           (p->guard_interval == GUARD_INTERVAL_AUTO) ||
           (p->transmission_mode == TRANSMISSION_MODE_AUTO)) {

                /* TPS Source - use hardware driven values */
                cx22702_writereg(state, 0x06, 0x10);
                cx22702_writereg(state, 0x07, 0x9);
                cx22702_writereg(state, 0x08, 0xC1);
                cx22702_writereg(state, 0x0B, cx22702_readreg(state, 0x0B)
                        & 0xfc);
                cx22702_writereg(state, 0x0C,
                        (cx22702_readreg(state, 0x0C) & 0xBF) | 0x40);
                cx22702_writereg(state, 0x00, 0x01); /* Begin acquisition */
                dprintk("%s: Autodetecting\n", __func__);
                return 0;
        }

        /* manually programmed values */
        switch (p->modulation) {                /* mask 0x18 */
        case QPSK:
                val = 0x00;
                break;
        case QAM_16:
                val = 0x08;
                break;
        case QAM_64:
                val = 0x10;
                break;
        default:
                dprintk("%s: invalid modulation\n", __func__);
                return -EINVAL;
        }
        switch (p->hierarchy) { /* mask 0x07 */
        case HIERARCHY_NONE:
                break;
        case HIERARCHY_1:
                val |= 0x01;
                break;
        case HIERARCHY_2:
                val |= 0x02;
                break;
        case HIERARCHY_4:
                val |= 0x03;
                break;
        default:
                dprintk("%s: invalid hierarchy\n", __func__);
                return -EINVAL;
        }
        cx22702_writereg(state, 0x06, val);

        switch (p->code_rate_HP) {              /* mask 0x38 */
        case FEC_NONE:
        case FEC_1_2:
                val = 0x00;
                break;
        case FEC_2_3:
                val = 0x08;
                break;
        case FEC_3_4:
                val = 0x10;
                break;
        case FEC_5_6:
                val = 0x18;
                break;
        case FEC_7_8:
                val = 0x20;
                break;
        default:
                dprintk("%s: invalid code_rate_HP\n", __func__);
                return -EINVAL;
        }
        switch (p->code_rate_LP) {              /* mask 0x07 */
        case FEC_NONE:
        case FEC_1_2:
                break;
        case FEC_2_3:
                val |= 0x01;
                break;
        case FEC_3_4:
                val |= 0x02;
                break;
        case FEC_5_6:
                val |= 0x03;
                break;
        case FEC_7_8:
                val |= 0x04;
                break;
        default:
                dprintk("%s: invalid code_rate_LP\n", __func__);
                return -EINVAL;
        }
        cx22702_writereg(state, 0x07, val);

        switch (p->guard_interval) {            /* mask 0x0c */
        case GUARD_INTERVAL_1_32:
                val = 0x00;
                break;
        case GUARD_INTERVAL_1_16:
                val = 0x04;
                break;
        case GUARD_INTERVAL_1_8:
                val = 0x08;
                break;
        case GUARD_INTERVAL_1_4:
                val = 0x0c;
                break;
        default:
                dprintk("%s: invalid guard_interval\n", __func__);
                return -EINVAL;
        }
        switch (p->transmission_mode) {         /* mask 0x03 */
        case TRANSMISSION_MODE_2K:
                break;
        case TRANSMISSION_MODE_8K:
                val |= 0x1;
                break;
        default:
                dprintk("%s: invalid transmission_mode\n", __func__);
                return -EINVAL;
        }
        cx22702_writereg(state, 0x08, val);
        cx22702_writereg(state, 0x0B,
                (cx22702_readreg(state, 0x0B) & 0xfc) | 0x02);
        cx22702_writereg(state, 0x0C,
                (cx22702_readreg(state, 0x0C) & 0xBF) | 0x40);

        /* Begin channel acquisition */
        cx22702_writereg(state, 0x00, 0x01);

        return 0;
}

/* Reset the demod hardware and reset all of the configuration registers
   to a default state. */
static int cx22702_init(struct dvb_frontend *fe)
{
        int i;
        struct cx22702_state *state = fe->demodulator_priv;

        cx22702_writereg(state, 0x00, 0x02);

        msleep(10);

        for (i = 0; i < ARRAY_SIZE(init_tab); i += 2)
                cx22702_writereg(state, init_tab[i], init_tab[i + 1]);

        cx22702_writereg(state, 0xf8, (state->config->output_mode << 1)
                & 0x02);

        cx22702_i2c_gate_ctrl(fe, 0);

        return 0;
}

static int cx22702_read_status(struct dvb_frontend *fe, enum fe_status *status)
{
        struct cx22702_state *state = fe->demodulator_priv;
        u8 reg0A;
        u8 reg23;

        *status = 0;

        reg0A = cx22702_readreg(state, 0x0A);
        reg23 = cx22702_readreg(state, 0x23);

        dprintk("%s: status demod=0x%02x agc=0x%02x\n"
                , __func__, reg0A, reg23);

        if (reg0A & 0x10) {
                *status |= FE_HAS_LOCK;
                *status |= FE_HAS_VITERBI;
                *status |= FE_HAS_SYNC;
        }

        if (reg0A & 0x20)
                *status |= FE_HAS_CARRIER;

        if (reg23 < 0xf0)
                *status |= FE_HAS_SIGNAL;

        return 0;
}

static int cx22702_read_ber(struct dvb_frontend *fe, u32 *ber)
{
        struct cx22702_state *state = fe->demodulator_priv;

        if (cx22702_readreg(state, 0xE4) & 0x02) {
                /* Realtime statistics */
                *ber = (cx22702_readreg(state, 0xDE) & 0x7F) << 7
                        | (cx22702_readreg(state, 0xDF) & 0x7F);
        } else {
                /* Averagtine statistics */
                *ber = (cx22702_readreg(state, 0xDE) & 0x7F) << 7
                        | cx22702_readreg(state, 0xDF);
        }

        return 0;
}

static int cx22702_read_signal_strength(struct dvb_frontend *fe,
        u16 *signal_strength)
{
        struct cx22702_state *state = fe->demodulator_priv;
        u8 reg23;

        /*
         * Experience suggests that the strength signal register works as
         * follows:
         * - In the absence of signal, value is 0xff.
         * - In the presence of a weak signal, bit 7 is set, not sure what
         *   the lower 7 bits mean.
         * - In the presence of a strong signal, the register holds a 7-bit
         *   value (bit 7 is cleared), with greater values standing for
         *   weaker signals.
         */
        reg23 = cx22702_readreg(state, 0x23);
        if (reg23 & 0x80) {
                *signal_strength = 0;
        } else {
                reg23 = ~reg23 & 0x7f;
                /* Scale to 16 bit */
                *signal_strength = (reg23 << 9) | (reg23 << 2) | (reg23 >> 5);
        }

        return 0;
}

static int cx22702_read_snr(struct dvb_frontend *fe, u16 *snr)
{
        struct cx22702_state *state = fe->demodulator_priv;

        u16 rs_ber;
        if (cx22702_readreg(state, 0xE4) & 0x02) {
                /* Realtime statistics */
                rs_ber = (cx22702_readreg(state, 0xDE) & 0x7F) << 7
                        | (cx22702_readreg(state, 0xDF) & 0x7F);
        } else {
                /* Averagine statistics */
                rs_ber = (cx22702_readreg(state, 0xDE) & 0x7F) << 8
                        | cx22702_readreg(state, 0xDF);
        }
        *snr = ~rs_ber;

        return 0;
}

static int cx22702_read_ucblocks(struct dvb_frontend *fe, u32 *ucblocks)
{
        struct cx22702_state *state = fe->demodulator_priv;

        u8 _ucblocks;

        /* RS Uncorrectable Packet Count then reset */
        _ucblocks = cx22702_readreg(state, 0xE3);
        if (state->prevUCBlocks < _ucblocks)
                *ucblocks = (_ucblocks - state->prevUCBlocks);
        else
                *ucblocks = state->prevUCBlocks - _ucblocks;
        state->prevUCBlocks = _ucblocks;

        return 0;
}

static int cx22702_get_frontend(struct dvb_frontend *fe,
                                struct dtv_frontend_properties *c)
{
        struct cx22702_state *state = fe->demodulator_priv;

        u8 reg0C = cx22702_readreg(state, 0x0C);

        c->inversion = reg0C & 0x1 ? INVERSION_ON : INVERSION_OFF;
        return cx22702_get_tps(state, c);
}

static int cx22702_get_tune_settings(struct dvb_frontend *fe,
        struct dvb_frontend_tune_settings *tune)
{
        tune->min_delay_ms = 1000;
        return 0;
}

static void cx22702_release(struct dvb_frontend *fe)
{
        struct cx22702_state *state = fe->demodulator_priv;
        kfree(state);
}

static const struct dvb_frontend_ops cx22702_ops;

struct dvb_frontend *cx22702_attach(const struct cx22702_config *config,
        struct i2c_adapter *i2c)
{
        struct cx22702_state *state = NULL;

        /* allocate memory for the internal state */
        state = kzalloc_obj(struct cx22702_state);
        if (state == NULL)
                goto error;

        /* setup the state */
        state->config = config;
        state->i2c = i2c;

        /* check if the demod is there */
        if (cx22702_readreg(state, 0x1f) != 0x3)
                goto error;

        /* create dvb_frontend */
        memcpy(&state->frontend.ops, &cx22702_ops,
                sizeof(struct dvb_frontend_ops));
        state->frontend.demodulator_priv = state;
        return &state->frontend;

error:
        kfree(state);
        return NULL;
}
EXPORT_SYMBOL_GPL(cx22702_attach);

static const struct dvb_frontend_ops cx22702_ops = {
        .delsys = { SYS_DVBT },
        .info = {
                .name                   = "Conexant CX22702 DVB-T",
                .frequency_min_hz       = 177 * MHz,
                .frequency_max_hz       = 858 * MHz,
                .frequency_stepsize_hz  = 166666,
                .caps = FE_CAN_FEC_1_2 | FE_CAN_FEC_2_3 | FE_CAN_FEC_3_4 |
                FE_CAN_FEC_5_6 | FE_CAN_FEC_7_8 | FE_CAN_FEC_AUTO |
                FE_CAN_QPSK | FE_CAN_QAM_16 | FE_CAN_QAM_64 | FE_CAN_QAM_AUTO |
                FE_CAN_HIERARCHY_AUTO | FE_CAN_GUARD_INTERVAL_AUTO |
                FE_CAN_TRANSMISSION_MODE_AUTO | FE_CAN_RECOVER
        },

        .release = cx22702_release,

        .init = cx22702_init,
        .i2c_gate_ctrl = cx22702_i2c_gate_ctrl,

        .set_frontend = cx22702_set_tps,
        .get_frontend = cx22702_get_frontend,
        .get_tune_settings = cx22702_get_tune_settings,

        .read_status = cx22702_read_status,
        .read_ber = cx22702_read_ber,
        .read_signal_strength = cx22702_read_signal_strength,
        .read_snr = cx22702_read_snr,
        .read_ucblocks = cx22702_read_ucblocks,
};

MODULE_DESCRIPTION("Conexant CX22702 DVB-T Demodulator driver");
MODULE_AUTHOR("Steven Toth");
MODULE_LICENSE("GPL");