/**
 * Driver for Sharp IX2505V (marked B0017) DVB-S silicon tuner
 *
 * Copyright (C) 2010 Malcolm Priestley
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License Version 2, as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

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

#include "ix2505v.h"

static int ix2505v_debug;
#define dprintk(level, args...) do { \
        if (ix2505v_debug & level) \
                printk(KERN_DEBUG "ix2505v: " args); \
} while (0)

#define deb_info(args...)  dprintk(0x01, args)
#define deb_i2c(args...)  dprintk(0x02, args)

struct ix2505v_state {
        struct i2c_adapter *i2c;
        const struct ix2505v_config *config;
        u32 frequency;
};

/**
 *  Data read format of the Sharp IX2505V B0017
 *
 *  byte1:   1   |   1   |   0   |   0   |   0   |  MA1  |  MA0  |  1
 *  byte2:  POR  |   FL  |  RD2  |  RD1  |  RD0  |   X   |   X   |  X
 *
 *  byte1 = address
 *  byte2;
 *      POR = Power on Reset (VCC H=<2.2v L=>2.2v)
 *      FL  = Phase Lock (H=lock L=unlock)
 *      RD0-2 = Reserved internal operations
 *
 * Only POR can be used to check the tuner is present
 *
 * Caution: after byte2 the I2C reverts to write mode continuing to read
 *          may corrupt tuning data.
 *
 */

static int ix2505v_read_status_reg(struct ix2505v_state *state)
{
        u8 addr = state->config->tuner_address;
        u8 b2[] = {0};
        int ret;

        struct i2c_msg msg[1] = {
                { .addr = addr, .flags = I2C_M_RD, .buf = b2, .len = 1 }
        };

        ret = i2c_transfer(state->i2c, msg, 1);
        deb_i2c("Read %s ", __func__);

        return (ret == 1) ? (int) b2[0] : -1;
}

static int ix2505v_write(struct ix2505v_state *state, u8 buf[], u8 count)
{
        struct i2c_msg msg[1] = {
                { .addr = state->config->tuner_address, .flags = 0,
                  .buf = buf, .len = count },
        };

        int ret;

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

        if (ret != 1) {
                deb_i2c("%s: i2c error, ret=%d\n", __func__, ret);
                return -EIO;
        }

        return 0;
}

static void ix2505v_release(struct dvb_frontend *fe)
{
        struct ix2505v_state *state = fe->tuner_priv;

        fe->tuner_priv = NULL;
        kfree(state);

}

/**
 *  Data write format of the Sharp IX2505V B0017
 *
 *  byte1:   1   |   1   |   0   |   0   |   0   | 0(MA1)| 0(MA0)|  0
 *  byte2:   0   |  BG1  |  BG2  |   N8  |   N7  |   N6  |  N5   |  N4
 *  byte3:   N3  |   N2  |   N1  |   A5  |   A4  |   A3  |   A2  |  A1
 *  byte4:   1   | 1(C1) | 1(C0) |  PD5  |  PD4  |   TM  | 0(RTS)| 1(REF)
 *  byte5:   BA2 |   BA1 |  BA0  |  PSC  |  PD3  |PD2/TS2|DIV/TS1|PD0/TS0
 *
 *  byte1 = address
 *
 *  Write order
 *  1) byte1 -> byte2 -> byte3 -> byte4 -> byte5
 *  2) byte1 -> byte4 -> byte5 -> byte2 -> byte3
 *  3) byte1 -> byte2 -> byte3 -> byte4
 *  4) byte1 -> byte4 -> byte5 -> byte2
 *  5) byte1 -> byte2 -> byte3
 *  6) byte1 -> byte4 -> byte5
 *  7) byte1 -> byte2
 *  8) byte1 -> byte4
 *
 *  Recommended Setup
 *  1 -> 8 -> 6
 */

static int ix2505v_set_params(struct dvb_frontend *fe)
{
        struct dtv_frontend_properties *c = &fe->dtv_property_cache;
        struct ix2505v_state *state = fe->tuner_priv;
        u32 frequency = c->frequency;
        u32 b_w  = (c->symbol_rate * 27) / 32000;
        u32 div_factor, N , A, x;
        int ret = 0, len;
        u8 gain, cc, ref, psc, local_osc, lpf;
        u8 data[4] = {0};

        if ((frequency < fe->ops.info.frequency_min)
        ||  (frequency > fe->ops.info.frequency_max))
                return -EINVAL;

        if (state->config->tuner_gain)
                gain = (state->config->tuner_gain < 4)
                        ? state->config->tuner_gain : 0;
        else
                gain = 0x0;

        if (state->config->tuner_chargepump)
                cc = state->config->tuner_chargepump;
        else
                cc = 0x3;

        ref = 8; /* REF =1 */
        psc = 32; /* PSC = 0 */

        div_factor = (frequency * ref) / 40; /* local osc = 4Mhz */
        x = div_factor / psc;
        N = x/100;
        A = ((x - (N * 100)) * psc) / 100;

        data[0] = ((gain & 0x3) << 5) | (N >> 3);
        data[1] = (N << 5) | (A & 0x1f);
        data[2] = 0x81 | ((cc & 0x3) << 5) ; /*PD5,PD4 & TM = 0|C1,C0|REF=1*/

        deb_info("Frq=%d x=%d N=%d A=%d\n", frequency, x, N, A);

        if (frequency <= 1065000)
                local_osc = (6 << 5) | 2;
        else if (frequency <= 1170000)
                local_osc = (7 << 5) | 2;
        else if (frequency <= 1300000)
                local_osc = (1 << 5);
        else if (frequency <= 1445000)
                local_osc = (2 << 5);
        else if (frequency <= 1607000)
                local_osc = (3 << 5);
        else if (frequency <= 1778000)
                local_osc = (4 << 5);
        else if (frequency <= 1942000)
                local_osc = (5 << 5);
        else            /*frequency up to 2150000*/
                local_osc = (6 << 5);

        data[3] = local_osc; /* all other bits set 0 */

        if (b_w <= 10000)
                lpf = 0xc;
        else if (b_w <= 12000)
                lpf = 0x2;
        else if (b_w <= 14000)
                lpf = 0xa;
        else if (b_w <= 16000)
                lpf = 0x6;
        else if (b_w <= 18000)
                lpf = 0xe;
        else if (b_w <= 20000)
                lpf = 0x1;
        else if (b_w <= 22000)
                lpf = 0x9;
        else if (b_w <= 24000)
                lpf = 0x5;
        else if (b_w <= 26000)
                lpf = 0xd;
        else if (b_w <= 28000)
                lpf = 0x3;
                else
                lpf = 0xb;

        deb_info("Osc=%x b_w=%x lpf=%x\n", local_osc, b_w, lpf);
        deb_info("Data 0=[%4phN]\n", data);

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

        len = sizeof(data);
        ret |= ix2505v_write(state, data, len);

        data[2] |= 0x4; /* set TM = 1 other bits same */

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

        len = 1;
        ret |= ix2505v_write(state, &data[2], len); /* write byte 4 only */

        msleep(10);

        data[2] |= ((lpf >> 2) & 0x3) << 3; /* lpf */
        data[3] |= (lpf & 0x3) << 2;

        deb_info("Data 2=[%x%x]\n", data[2], data[3]);

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

        len = 2;
        ret |= ix2505v_write(state, &data[2], len); /* write byte 4 & 5 */

        if (state->config->min_delay_ms)
                msleep(state->config->min_delay_ms);

        state->frequency = frequency;

        return ret;
}

static int ix2505v_get_frequency(struct dvb_frontend *fe, u32 *frequency)
{
        struct ix2505v_state *state = fe->tuner_priv;

        *frequency = state->frequency;

        return 0;
}

static const struct dvb_tuner_ops ix2505v_tuner_ops = {
        .info = {
                .name = "Sharp IX2505V (B0017)",
                .frequency_min = 950000,
                .frequency_max = 2175000
        },
        .release = ix2505v_release,
        .set_params = ix2505v_set_params,
        .get_frequency = ix2505v_get_frequency,
};

struct dvb_frontend *ix2505v_attach(struct dvb_frontend *fe,
                                    const struct ix2505v_config *config,
                                    struct i2c_adapter *i2c)
{
        struct ix2505v_state *state = NULL;
        int ret;

        if (NULL == config) {
                deb_i2c("%s: no config ", __func__);
                goto error;
        }

        state = kzalloc(sizeof(struct ix2505v_state), GFP_KERNEL);
        if (NULL == state)
                return NULL;

        state->config = config;
        state->i2c = i2c;

        if (state->config->tuner_write_only) {
                if (fe->ops.i2c_gate_ctrl)
                        fe->ops.i2c_gate_ctrl(fe, 1);

                ret = ix2505v_read_status_reg(state);

                if (ret & 0x80) {
                        deb_i2c("%s: No IX2505V found\n", __func__);
                        goto error;
                }

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

        fe->tuner_priv = state;

        memcpy(&fe->ops.tuner_ops, &ix2505v_tuner_ops,
                sizeof(struct dvb_tuner_ops));
        deb_i2c("%s: initialization (%s addr=0x%02x) ok\n",
                __func__, fe->ops.tuner_ops.info.name, config->tuner_address);

        return fe;

error:
        kfree(state);
        return NULL;
}
EXPORT_SYMBOL(ix2505v_attach);

module_param_named(debug, ix2505v_debug, int, 0644);
MODULE_PARM_DESC(debug, "Turn on/off frontend debugging (default:off).");
MODULE_DESCRIPTION("DVB IX2505V tuner driver");
MODULE_AUTHOR("Malcolm Priestley");
MODULE_LICENSE("GPL");