sp887x.c

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/*
   Driver for the Spase sp887x demodulator
*/

/*
 * This driver needs external firmware. Please use the command
 * "<kerneldir>/Documentation/dvb/get_dvb_firmware sp887x" to
 * download/extract it, and then copy it to /usr/lib/hotplug/firmware
 * or /lib/firmware (depending on configuration of firmware hotplug).
 */
#define SP887X_DEFAULT_FIRMWARE "dvb-fe-sp887x.fw"

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/firmware.h>
#include <linux/string.h>
#include <linux/slab.h>

#include "dvb_frontend.h"
#include "sp887x.h"


struct sp887x_state {
    struct i2c_adapter* i2c;
    const struct sp887x_config* config;
    struct dvb_frontend frontend;

    /* demodulator private data */
    u8 initialised:1;
};

static int debug;
#define dprintk(args...) \
    do { \
        if (debug) printk(KERN_DEBUG "sp887x: " args); \
    } while (0)

static int i2c_writebytes (struct sp887x_state* state, u8 *buf, u8 len)
{
    struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = buf, .len = len };
    int err;

    if ((err = i2c_transfer (state->i2c, &msg, 1)) != 1) {
        printk ("%s: i2c write error (addr %02x, err == %i)\n",
            __func__, state->config->demod_address, err);
        return -EREMOTEIO;
    }

    return 0;
}

static int sp887x_writereg (struct sp887x_state* state, u16 reg, u16 data)
{
    u8 b0 [] = { reg >> 8 , reg & 0xff, data >> 8, data & 0xff };
    struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = b0, .len = 4 };
    int ret;

    if ((ret = i2c_transfer(state->i2c, &msg, 1)) != 1) {
        if (!(reg == 0xf1a && data == 0x000 &&
            (ret == -EREMOTEIO || ret == -EFAULT)))
        {
            printk("%s: writereg error "
                   "(reg %03x, data %03x, ret == %i)\n",
                   __func__, reg & 0xffff, data & 0xffff, ret);
            return ret;
        }
    }

    return 0;
}

static int sp887x_readreg (struct sp887x_state* state, u16 reg)
{
    u8 b0 [] = { reg >> 8 , reg & 0xff };
    u8 b1 [2];
    int ret;
    struct i2c_msg msg[] = {{ .addr = state->config->demod_address, .flags = 0, .buf = b0, .len = 2 },
             { .addr = state->config->demod_address, .flags = I2C_M_RD, .buf = b1, .len = 2 }};

    if ((ret = i2c_transfer(state->i2c, msg, 2)) != 2) {
        printk("%s: readreg error (ret == %i)\n", __func__, ret);
        return -1;
    }

    return (((b1[0] << 8) | b1[1]) & 0xfff);
}

static void sp887x_microcontroller_stop (struct sp887x_state* state)
{
    dprintk("%s\n", __func__);
    sp887x_writereg(state, 0xf08, 0x000);
    sp887x_writereg(state, 0xf09, 0x000);

    /* microcontroller STOP */
    sp887x_writereg(state, 0xf00, 0x000);
}

static void sp887x_microcontroller_start (struct sp887x_state* state)
{
    dprintk("%s\n", __func__);
    sp887x_writereg(state, 0xf08, 0x000);
    sp887x_writereg(state, 0xf09, 0x000);

    /* microcontroller START */
    sp887x_writereg(state, 0xf00, 0x001);
}

static void sp887x_setup_agc (struct sp887x_state* state)
{
    /* setup AGC parameters */
    dprintk("%s\n", __func__);
    sp887x_writereg(state, 0x33c, 0x054);
    sp887x_writereg(state, 0x33b, 0x04c);
    sp887x_writereg(state, 0x328, 0x000);
    sp887x_writereg(state, 0x327, 0x005);
    sp887x_writereg(state, 0x326, 0x001);
    sp887x_writereg(state, 0x325, 0x001);
    sp887x_writereg(state, 0x324, 0x001);
    sp887x_writereg(state, 0x318, 0x050);
    sp887x_writereg(state, 0x317, 0x3fe);
    sp887x_writereg(state, 0x316, 0x001);
    sp887x_writereg(state, 0x313, 0x005);
    sp887x_writereg(state, 0x312, 0x002);
    sp887x_writereg(state, 0x306, 0x000);
    sp887x_writereg(state, 0x303, 0x000);
}

#define BLOCKSIZE 30
#define FW_SIZE 0x4000

static int sp887x_initial_setup (struct dvb_frontend* fe, const struct firmware *fw)
{
    struct sp887x_state* state = fe->demodulator_priv;
    u8 buf [BLOCKSIZE+2];
    int i;
    int fw_size = fw->size;
    const unsigned char *mem = fw->data;

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

    /* ignore the first 10 bytes, then we expect 0x4000 bytes of firmware */
    if (fw_size < FW_SIZE+10)
        return -ENODEV;

    mem = fw->data + 10;

    /* soft reset */
    sp887x_writereg(state, 0xf1a, 0x000);

    sp887x_microcontroller_stop (state);

    printk ("%s: firmware upload... ", __func__);

    /* setup write pointer to -1 (end of memory) */
    /* bit 0x8000 in address is set to enable 13bit mode */
    sp887x_writereg(state, 0x8f08, 0x1fff);

    /* dummy write (wrap around to start of memory) */
    sp887x_writereg(state, 0x8f0a, 0x0000);

    for (i = 0; i < FW_SIZE; i += BLOCKSIZE) {
        int c = BLOCKSIZE;
        int err;

        if (i+c > FW_SIZE)
            c = FW_SIZE - i;

        /* bit 0x8000 in address is set to enable 13bit mode */
        /* bit 0x4000 enables multibyte read/write transfers */
        /* write register is 0xf0a */
        buf[0] = 0xcf;
        buf[1] = 0x0a;

        memcpy(&buf[2], mem + i, c);

        if ((err = i2c_writebytes (state, buf, c+2)) < 0) {
            printk ("failed.\n");
            printk ("%s: i2c error (err == %i)\n", __func__, err);
            return err;
        }
    }

    /* don't write RS bytes between packets */
    sp887x_writereg(state, 0xc13, 0x001);

    /* suppress clock if (!data_valid) */
    sp887x_writereg(state, 0xc14, 0x000);

    /* setup MPEG interface... */
    sp887x_writereg(state, 0xc1a, 0x872);
    sp887x_writereg(state, 0xc1b, 0x001);
    sp887x_writereg(state, 0xc1c, 0x000); /* parallel mode (serial mode == 1) */
    sp887x_writereg(state, 0xc1a, 0x871);

    /* ADC mode, 2 for MT8872, 3 for SP8870/SP8871 */
    sp887x_writereg(state, 0x301, 0x002);

    sp887x_setup_agc(state);

    /* bit 0x010: enable data valid signal */
    sp887x_writereg(state, 0xd00, 0x010);
    sp887x_writereg(state, 0x0d1, 0x000);
    return 0;
};

static int configure_reg0xc05(struct dtv_frontend_properties *p, u16 *reg0xc05)
{
    int known_parameters = 1;

    *reg0xc05 = 0x000;

    switch (p->modulation) {
    case QPSK:
        break;
    case QAM_16:
        *reg0xc05 |= (1 << 10);
        break;
    case QAM_64:
        *reg0xc05 |= (2 << 10);
        break;
    case QAM_AUTO:
        known_parameters = 0;
        break;
    default:
        return -EINVAL;
    }

    switch (p->hierarchy) {
    case HIERARCHY_NONE:
        break;
    case HIERARCHY_1:
        *reg0xc05 |= (1 << 7);
        break;
    case HIERARCHY_2:
        *reg0xc05 |= (2 << 7);
        break;
    case HIERARCHY_4:
        *reg0xc05 |= (3 << 7);
        break;
    case HIERARCHY_AUTO:
        known_parameters = 0;
        break;
    default:
        return -EINVAL;
    }

    switch (p->code_rate_HP) {
    case FEC_1_2:
        break;
    case FEC_2_3:
        *reg0xc05 |= (1 << 3);
        break;
    case FEC_3_4:
        *reg0xc05 |= (2 << 3);
        break;
    case FEC_5_6:
        *reg0xc05 |= (3 << 3);
        break;
    case FEC_7_8:
        *reg0xc05 |= (4 << 3);
        break;
    case FEC_AUTO:
        known_parameters = 0;
        break;
    default:
        return -EINVAL;
    }

    if (known_parameters)
        *reg0xc05 |= (2 << 1);  /* use specified parameters */
    else
        *reg0xc05 |= (1 << 1);  /* enable autoprobing */

    return 0;
}

static void divide (int n, int d, int *quotient_i, int *quotient_f)
{
    unsigned int q, r;

    r = (n % d) << 8;
    q = (r / d);

    if (quotient_i)
        *quotient_i = q;

    if (quotient_f) {
        r = (r % d) << 8;
        q = (q << 8) | (r / d);
        r = (r % d) << 8;
        *quotient_f = (q << 8) | (r / d);
    }
}

static void sp887x_correct_offsets (struct sp887x_state* state,
                    struct dtv_frontend_properties *p,
                    int actual_freq)
{
    static const u32 srate_correction [] = { 1879617, 4544878, 8098561 };
    int bw_index;
    int freq_offset = actual_freq - p->frequency;
    int sysclock = 61003; //[kHz]
    int ifreq = 36000000;
    int freq;
    int frequency_shift;

    switch (p->bandwidth_hz) {
    default:
    case 8000000:
        bw_index = 0;
        break;
    case 7000000:
        bw_index = 1;
        break;
    case 6000000:
        bw_index = 2;
        break;
    }

    if (p->inversion == INVERSION_ON)
        freq = ifreq - freq_offset;
    else
        freq = ifreq + freq_offset;

    divide(freq / 333, sysclock, NULL, &frequency_shift);

    if (p->inversion == INVERSION_ON)
        frequency_shift = -frequency_shift;

    /* sample rate correction */
    sp887x_writereg(state, 0x319, srate_correction[bw_index] >> 12);
    sp887x_writereg(state, 0x31a, srate_correction[bw_index] & 0xfff);

    /* carrier offset correction */
    sp887x_writereg(state, 0x309, frequency_shift >> 12);
    sp887x_writereg(state, 0x30a, frequency_shift & 0xfff);
}

static int sp887x_setup_frontend_parameters(struct dvb_frontend *fe)
{
    struct dtv_frontend_properties *p = &fe->dtv_property_cache;
    struct sp887x_state* state = fe->demodulator_priv;
    unsigned actual_freq;
    int err;
    u16 val, reg0xc05;

    if (p->bandwidth_hz != 8000000 &&
        p->bandwidth_hz != 7000000 &&
        p->bandwidth_hz != 6000000)
        return -EINVAL;

    if ((err = configure_reg0xc05(p, &reg0xc05)))
        return err;

    sp887x_microcontroller_stop(state);

    /* setup the PLL */
    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);
    }
    if (fe->ops.tuner_ops.get_frequency) {
        fe->ops.tuner_ops.get_frequency(fe, &actual_freq);
        if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 0);
    } else {
        actual_freq = p->frequency;
    }

    /* read status reg in order to clear <pending irqs */
    sp887x_readreg(state, 0x200);

    sp887x_correct_offsets(state, p, actual_freq);

    /* filter for 6/7/8 Mhz channel */
    if (p->bandwidth_hz == 6000000)
        val = 2;
    else if (p->bandwidth_hz == 7000000)
        val = 1;
    else
        val = 0;

    sp887x_writereg(state, 0x311, val);

    /* scan order: 2k first = 0, 8k first = 1 */
    if (p->transmission_mode == TRANSMISSION_MODE_2K)
        sp887x_writereg(state, 0x338, 0x000);
    else
        sp887x_writereg(state, 0x338, 0x001);

    sp887x_writereg(state, 0xc05, reg0xc05);

    if (p->bandwidth_hz == 6000000)
        val = 2 << 3;
    else if (p->bandwidth_hz == 7000000)
        val = 3 << 3;
    else
        val = 0 << 3;

    /* enable OFDM and SAW bits as lock indicators in sync register 0xf17,
     * optimize algorithm for given bandwidth...
     */
    sp887x_writereg(state, 0xf14, 0x160 | val);
    sp887x_writereg(state, 0xf15, 0x000);

    sp887x_microcontroller_start(state);
    return 0;
}

static int sp887x_read_status(struct dvb_frontend* fe, fe_status_t* status)
{
    struct sp887x_state* state = fe->demodulator_priv;
    u16 snr12 = sp887x_readreg(state, 0xf16);
    u16 sync0x200 = sp887x_readreg(state, 0x200);
    u16 sync0xf17 = sp887x_readreg(state, 0xf17);

    *status = 0;

    if (snr12 > 0x00f)
        *status |= FE_HAS_SIGNAL;

    //if (sync0x200 & 0x004)
    //  *status |= FE_HAS_SYNC | FE_HAS_CARRIER;

    //if (sync0x200 & 0x008)
    //  *status |= FE_HAS_VITERBI;

    if ((sync0xf17 & 0x00f) == 0x002) {
        *status |= FE_HAS_LOCK;
        *status |= FE_HAS_VITERBI | FE_HAS_SYNC | FE_HAS_CARRIER;
    }

    if (sync0x200 & 0x001) {    /* tuner adjustment requested...*/
        int steps = (sync0x200 >> 4) & 0x00f;
        if (steps & 0x008)
            steps = -steps;
        dprintk("sp887x: implement tuner adjustment (%+i steps)!!\n",
               steps);
    }

    return 0;
}

static int sp887x_read_ber(struct dvb_frontend* fe, u32* ber)
{
    struct sp887x_state* state = fe->demodulator_priv;

    *ber = (sp887x_readreg(state, 0xc08) & 0x3f) |
           (sp887x_readreg(state, 0xc07) << 6);
    sp887x_writereg(state, 0xc08, 0x000);
    sp887x_writereg(state, 0xc07, 0x000);
    if (*ber >= 0x3fff0)
        *ber = ~0;

    return 0;
}

static int sp887x_read_signal_strength(struct dvb_frontend* fe, u16* strength)
{
    struct sp887x_state* state = fe->demodulator_priv;

    u16 snr12 = sp887x_readreg(state, 0xf16);
    u32 signal = 3 * (snr12 << 4);
    *strength = (signal < 0xffff) ? signal : 0xffff;

    return 0;
}

static int sp887x_read_snr(struct dvb_frontend* fe, u16* snr)
{
    struct sp887x_state* state = fe->demodulator_priv;

    u16 snr12 = sp887x_readreg(state, 0xf16);
    *snr = (snr12 << 4) | (snr12 >> 8);

    return 0;
}

static int sp887x_read_ucblocks(struct dvb_frontend* fe, u32* ucblocks)
{
    struct sp887x_state* state = fe->demodulator_priv;

    *ucblocks = sp887x_readreg(state, 0xc0c);
    if (*ucblocks == 0xfff)
        *ucblocks = ~0;

    return 0;
}

static int sp887x_i2c_gate_ctrl(struct dvb_frontend* fe, int enable)
{
    struct sp887x_state* state = fe->demodulator_priv;

    if (enable) {
        return sp887x_writereg(state, 0x206, 0x001);
    } else {
        return sp887x_writereg(state, 0x206, 0x000);
    }
}

static int sp887x_sleep(struct dvb_frontend* fe)
{
    struct sp887x_state* state = fe->demodulator_priv;

    /* tristate TS output and disable interface pins */
    sp887x_writereg(state, 0xc18, 0x000);

    return 0;
}

static int sp887x_init(struct dvb_frontend* fe)
{
    struct sp887x_state* state = fe->demodulator_priv;
    const struct firmware *fw = NULL;
    int ret;

    if (!state->initialised) {
        /* request the firmware, this will block until someone uploads it */
        printk("sp887x: waiting for firmware upload (%s)...\n", SP887X_DEFAULT_FIRMWARE);
        ret = state->config->request_firmware(fe, &fw, SP887X_DEFAULT_FIRMWARE);
        if (ret) {
            printk("sp887x: no firmware upload (timeout or file not found?)\n");
            return ret;
        }

        ret = sp887x_initial_setup(fe, fw);
        release_firmware(fw);
        if (ret) {
            printk("sp887x: writing firmware to device failed\n");
            return ret;
        }
        printk("sp887x: firmware upload complete\n");
        state->initialised = 1;
    }

    /* enable TS output and interface pins */
    sp887x_writereg(state, 0xc18, 0x00d);

    return 0;
}

static int sp887x_get_tune_settings(struct dvb_frontend* fe, struct dvb_frontend_tune_settings* fesettings)
{
    fesettings->min_delay_ms = 350;
    fesettings->step_size = 166666*2;
    fesettings->max_drift = (166666*2)+1;
    return 0;
}

static void sp887x_release(struct dvb_frontend* fe)
{
    struct sp887x_state* state = fe->demodulator_priv;
    kfree(state);
}

static struct dvb_frontend_ops sp887x_ops;

struct dvb_frontend* sp887x_attach(const struct sp887x_config* config,
                   struct i2c_adapter* i2c)
{
    struct sp887x_state* state = NULL;

    /* allocate memory for the internal state */
    state = kzalloc(sizeof(struct sp887x_state), GFP_KERNEL);
    if (state == NULL) goto error;

    /* setup the state */
    state->config = config;
    state->i2c = i2c;
    state->initialised = 0;

    /* check if the demod is there */
    if (sp887x_readreg(state, 0x0200) < 0) goto error;

    /* create dvb_frontend */
    memcpy(&state->frontend.ops, &sp887x_ops, sizeof(struct dvb_frontend_ops));
    state->frontend.demodulator_priv = state;
    return &state->frontend;

error:
    kfree(state);
    return NULL;
}

static struct dvb_frontend_ops sp887x_ops = {
    .delsys = { SYS_DVBT },
    .info = {
        .name = "Spase SP887x DVB-T",
        .frequency_min =  50500000,
        .frequency_max = 858000000,
        .frequency_stepsize = 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_RECOVER
    },

    .release = sp887x_release,

    .init = sp887x_init,
    .sleep = sp887x_sleep,
    .i2c_gate_ctrl = sp887x_i2c_gate_ctrl,

    .set_frontend = sp887x_setup_frontend_parameters,
    .get_tune_settings = sp887x_get_tune_settings,

    .read_status = sp887x_read_status,
    .read_ber = sp887x_read_ber,
    .read_signal_strength = sp887x_read_signal_strength,
    .read_snr = sp887x_read_snr,
    .read_ucblocks = sp887x_read_ucblocks,
};

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

MODULE_DESCRIPTION("Spase sp887x DVB-T demodulator driver");
MODULE_LICENSE("GPL");

EXPORT_SYMBOL(sp887x_attach);