// SPDX-License-Identifier: GPL-2.0-or-later
/*
    Conexant cx22700 DVB OFDM demodulator driver

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


*/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <media/dvb_frontend.h>
#include "cx22700.h"


struct cx22700_state {

        struct i2c_adapter* i2c;

        const struct cx22700_config* config;

        struct dvb_frontend frontend;
};


static int debug;
#define dprintk(args...) \
        do { \
                if (debug) printk(KERN_DEBUG "cx22700: " args); \
        } while (0)

static u8 init_tab [] = {
        0x04, 0x10,
        0x05, 0x09,
        0x06, 0x00,
        0x08, 0x04,
        0x09, 0x00,
        0x0a, 0x01,
        0x15, 0x40,
        0x16, 0x10,
        0x17, 0x87,
        0x18, 0x17,
        0x1a, 0x10,
        0x25, 0x04,
        0x2e, 0x00,
        0x39, 0x00,
        0x3a, 0x04,
        0x45, 0x08,
        0x46, 0x02,
        0x47, 0x05,
};


static int cx22700_writereg (struct cx22700_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 };

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

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

        if (ret != 1)
                printk("%s: writereg error (reg == 0x%02x, val == 0x%02x, ret == %i)\n",
                        __func__, reg, data, ret);

        return (ret != 1) ? -1 : 0;
}

static int cx22700_readreg (struct cx22700_state* state, u8 reg)
{
        int ret;
        u8 b0 [] = { reg };
        u8 b1 [] = { 0 };
        struct i2c_msg msg [] = { { .addr = state->config->demod_address, .flags = 0, .buf = b0, .len = 1 },
                           { .addr = state->config->demod_address, .flags = I2C_M_RD, .buf = b1, .len = 1 } };

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

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

        if (ret != 2) return -EIO;

        return b1[0];
}

static int cx22700_set_inversion (struct cx22700_state* state, int inversion)
{
        u8 val;

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

        switch (inversion) {
        case INVERSION_AUTO:
                return -EOPNOTSUPP;
        case INVERSION_ON:
                val = cx22700_readreg (state, 0x09);
                return cx22700_writereg (state, 0x09, val | 0x01);
        case INVERSION_OFF:
                val = cx22700_readreg (state, 0x09);
                return cx22700_writereg (state, 0x09, val & 0xfe);
        default:
                return -EINVAL;
        }
}

static int cx22700_set_tps(struct cx22700_state *state,
                           struct dtv_frontend_properties *p)
{
        static const u8 qam_tab [4] = { 0, 1, 0, 2 };
        static const u8 fec_tab [6] = { 0, 1, 2, 0, 3, 4 };
        u8 val;

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

        if (p->code_rate_HP < FEC_1_2 || p->code_rate_HP > FEC_7_8)
                return -EINVAL;

        if (p->code_rate_LP < FEC_1_2 || p->code_rate_LP > FEC_7_8)
                return -EINVAL;

        if (p->code_rate_HP == FEC_4_5 || p->code_rate_LP == FEC_4_5)
                return -EINVAL;

        if ((int)p->guard_interval < GUARD_INTERVAL_1_32 ||
            p->guard_interval > GUARD_INTERVAL_1_4)
                return -EINVAL;

        if (p->transmission_mode != TRANSMISSION_MODE_2K &&
            p->transmission_mode != TRANSMISSION_MODE_8K)
                return -EINVAL;

        if (p->modulation != QPSK &&
            p->modulation != QAM_16 &&
            p->modulation != QAM_64)
                return -EINVAL;

        if ((int)p->hierarchy < HIERARCHY_NONE ||
            p->hierarchy > HIERARCHY_4)
                return -EINVAL;

        if (p->bandwidth_hz > 8000000 || p->bandwidth_hz < 6000000)
                return -EINVAL;

        if (p->bandwidth_hz == 7000000)
                cx22700_writereg (state, 0x09, cx22700_readreg (state, 0x09 | 0x10));
        else
                cx22700_writereg (state, 0x09, cx22700_readreg (state, 0x09 & ~0x10));

        val = qam_tab[p->modulation - QPSK];
        val |= p->hierarchy - HIERARCHY_NONE;

        cx22700_writereg (state, 0x04, val);

        if (p->code_rate_HP - FEC_1_2 >= sizeof(fec_tab) ||
            p->code_rate_LP - FEC_1_2 >= sizeof(fec_tab))
                return -EINVAL;
        val = fec_tab[p->code_rate_HP - FEC_1_2] << 3;
        val |= fec_tab[p->code_rate_LP - FEC_1_2];

        cx22700_writereg (state, 0x05, val);

        val = (p->guard_interval - GUARD_INTERVAL_1_32) << 2;
        val |= p->transmission_mode - TRANSMISSION_MODE_2K;

        cx22700_writereg (state, 0x06, val);

        cx22700_writereg (state, 0x08, 0x04 | 0x02);  /* use user tps parameters */
        cx22700_writereg (state, 0x08, 0x04);         /* restart acquisition */

        return 0;
}

static int cx22700_get_tps(struct cx22700_state *state,
                           struct dtv_frontend_properties *p)
{
        static const enum fe_modulation qam_tab[3] = { QPSK, QAM_16, QAM_64 };
        static const enum fe_code_rate fec_tab[5] = {
                FEC_1_2, FEC_2_3, FEC_3_4, FEC_5_6, FEC_7_8
        };
        u8 val;

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

        if (!(cx22700_readreg(state, 0x07) & 0x20))  /*  tps valid? */
                return -EAGAIN;

        val = cx22700_readreg (state, 0x01);

        if ((val & 0x7) > 4)
                p->hierarchy = HIERARCHY_AUTO;
        else
                p->hierarchy = HIERARCHY_NONE + (val & 0x7);

        if (((val >> 3) & 0x3) > 2)
                p->modulation = QAM_AUTO;
        else
                p->modulation = qam_tab[(val >> 3) & 0x3];

        val = cx22700_readreg (state, 0x02);

        if (((val >> 3) & 0x07) > 4)
                p->code_rate_HP = FEC_AUTO;
        else
                p->code_rate_HP = fec_tab[(val >> 3) & 0x07];

        if ((val & 0x07) > 4)
                p->code_rate_LP = FEC_AUTO;
        else
                p->code_rate_LP = fec_tab[val & 0x07];

        val = cx22700_readreg (state, 0x03);

        p->guard_interval = GUARD_INTERVAL_1_32 + ((val >> 6) & 0x3);
        p->transmission_mode = TRANSMISSION_MODE_2K + ((val >> 5) & 0x1);

        return 0;
}

static int cx22700_init (struct dvb_frontend* fe)

{       struct cx22700_state* state = fe->demodulator_priv;
        int i;

        dprintk("cx22700_init: init chip\n");

        cx22700_writereg (state, 0x00, 0x02);   /*  soft reset */
        cx22700_writereg (state, 0x00, 0x00);

        msleep(10);

        for (i=0; i<sizeof(init_tab); i+=2)
                cx22700_writereg (state, init_tab[i], init_tab[i+1]);

        cx22700_writereg (state, 0x00, 0x01);

        return 0;
}

static int cx22700_read_status(struct dvb_frontend *fe, enum fe_status *status)
{
        struct cx22700_state* state = fe->demodulator_priv;

        u16 rs_ber = (cx22700_readreg (state, 0x0d) << 9)
                   | (cx22700_readreg (state, 0x0e) << 1);
        u8 sync = cx22700_readreg (state, 0x07);

        *status = 0;

        if (rs_ber < 0xff00)
                *status |= FE_HAS_SIGNAL;

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

        if (sync & 0x10)
                *status |= FE_HAS_VITERBI;

        if (sync & 0x10)
                *status |= FE_HAS_SYNC;

        if (*status == 0x0f)
                *status |= FE_HAS_LOCK;

        return 0;
}

static int cx22700_read_ber(struct dvb_frontend* fe, u32* ber)
{
        struct cx22700_state* state = fe->demodulator_priv;

        *ber = cx22700_readreg (state, 0x0c) & 0x7f;
        cx22700_writereg (state, 0x0c, 0x00);

        return 0;
}

static int cx22700_read_signal_strength(struct dvb_frontend* fe, u16* signal_strength)
{
        struct cx22700_state* state = fe->demodulator_priv;

        u16 rs_ber = (cx22700_readreg (state, 0x0d) << 9)
                   | (cx22700_readreg (state, 0x0e) << 1);
        *signal_strength = ~rs_ber;

        return 0;
}

static int cx22700_read_snr(struct dvb_frontend* fe, u16* snr)
{
        struct cx22700_state* state = fe->demodulator_priv;

        u16 rs_ber = (cx22700_readreg (state, 0x0d) << 9)
                   | (cx22700_readreg (state, 0x0e) << 1);
        *snr = ~rs_ber;

        return 0;
}

static int cx22700_read_ucblocks(struct dvb_frontend* fe, u32* ucblocks)
{
        struct cx22700_state* state = fe->demodulator_priv;

        *ucblocks = cx22700_readreg (state, 0x0f);
        cx22700_writereg (state, 0x0f, 0x00);

        return 0;
}

static int cx22700_set_frontend(struct dvb_frontend *fe)
{
        struct dtv_frontend_properties *c = &fe->dtv_property_cache;
        struct cx22700_state* state = fe->demodulator_priv;

        cx22700_writereg (state, 0x00, 0x02); /* XXX CHECKME: soft reset*/
        cx22700_writereg (state, 0x00, 0x00);

        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);
        }

        cx22700_set_inversion(state, c->inversion);
        cx22700_set_tps(state, c);
        cx22700_writereg (state, 0x37, 0x01);  /* PAL loop filter off */
        cx22700_writereg (state, 0x00, 0x01);  /* restart acquire */

        return 0;
}

static int cx22700_get_frontend(struct dvb_frontend *fe,
                                struct dtv_frontend_properties *c)
{
        struct cx22700_state* state = fe->demodulator_priv;
        u8 reg09 = cx22700_readreg (state, 0x09);

        c->inversion = reg09 & 0x1 ? INVERSION_ON : INVERSION_OFF;
        return cx22700_get_tps(state, c);
}

static int cx22700_i2c_gate_ctrl(struct dvb_frontend* fe, int enable)
{
        struct cx22700_state* state = fe->demodulator_priv;

        if (enable) {
                return cx22700_writereg(state, 0x0a, 0x00);
        } else {
                return cx22700_writereg(state, 0x0a, 0x01);
        }
}

static int cx22700_get_tune_settings(struct dvb_frontend* fe, struct dvb_frontend_tune_settings* fesettings)
{
        fesettings->min_delay_ms = 150;
        fesettings->step_size = 166667;
        fesettings->max_drift = 166667*2;
        return 0;
}

static void cx22700_release(struct dvb_frontend* fe)
{
        struct cx22700_state* state = fe->demodulator_priv;
        kfree(state);
}

static const struct dvb_frontend_ops cx22700_ops;

struct dvb_frontend* cx22700_attach(const struct cx22700_config* config,
                                    struct i2c_adapter* i2c)
{
        struct cx22700_state* state = NULL;

        /* allocate memory for the internal state */
        state = kzalloc_obj(struct cx22700_state);
        if (state == NULL) goto error;

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

        /* check if the demod is there */
        if (cx22700_readreg(state, 0x07) < 0) goto error;

        /* create dvb_frontend */
        memcpy(&state->frontend.ops, &cx22700_ops, sizeof(struct dvb_frontend_ops));
        state->frontend.demodulator_priv = state;
        return &state->frontend;

error:
        kfree(state);
        return NULL;
}

static const struct dvb_frontend_ops cx22700_ops = {
        .delsys = { SYS_DVBT },
        .info = {
                .name                   = "Conexant CX22700 DVB-T",
                .frequency_min_hz       = 470 * MHz,
                .frequency_max_hz       = 860 * MHz,
                .frequency_stepsize_hz  = 166667,
                .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_RECOVER
        },

        .release = cx22700_release,

        .init = cx22700_init,
        .i2c_gate_ctrl = cx22700_i2c_gate_ctrl,

        .set_frontend = cx22700_set_frontend,
        .get_frontend = cx22700_get_frontend,
        .get_tune_settings = cx22700_get_tune_settings,

        .read_status = cx22700_read_status,
        .read_ber = cx22700_read_ber,
        .read_signal_strength = cx22700_read_signal_strength,
        .read_snr = cx22700_read_snr,
        .read_ucblocks = cx22700_read_ucblocks,
};

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

MODULE_DESCRIPTION("Conexant CX22700 DVB-T Demodulator driver");
MODULE_AUTHOR("Holger Waechtler");
MODULE_LICENSE("GPL");

EXPORT_SYMBOL_GPL(cx22700_attach);