/*
  	TDA8261 8PSK/QPSK tuner driver
  	Copyright (C) Manu Abraham (abraham.manu@gmail.com)
  
  	This program is free software; you can redistribute it and/or modify
  	it under the terms of the GNU General Public License as published by
  	the Free Software Foundation; either version 2 of the License, or
  	(at your option) any later version.
  
  	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/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  
  #include "dvb_frontend.h"
  #include "tda8261.h"
  
  struct tda8261_state {
  	struct dvb_frontend		*fe;
  	struct i2c_adapter		*i2c;
  	const struct tda8261_config	*config;
  
  	/* state cache */
  	u32 frequency;
  	u32 bandwidth;
  };
  
  static int tda8261_read(struct tda8261_state *state, u8 *buf)
  {
  	const struct tda8261_config *config = state->config;
  	int err = 0;
  	struct i2c_msg msg = { .addr	= config->addr, .flags = I2C_M_RD,.buf = buf,  .len = 1 };
  
  	if ((err = i2c_transfer(state->i2c, &msg, 1)) != 1)
  		pr_err("%s: read error, err=%d
  ", __func__, err);
  
  	return err;
  }
  
  static int tda8261_write(struct tda8261_state *state, u8 *buf)
  {
  	const struct tda8261_config *config = state->config;
  	int err = 0;
  	struct i2c_msg msg = { .addr = config->addr, .flags = 0, .buf = buf, .len = 4 };
  
  	if ((err = i2c_transfer(state->i2c, &msg, 1)) != 1)
  		pr_err("%s: write error, err=%d
  ", __func__, err);
  
  	return err;
  }
  
  static int tda8261_get_status(struct dvb_frontend *fe, u32 *status)
  {
  	struct tda8261_state *state = fe->tuner_priv;
  	u8 result = 0;
  	int err = 0;
  
  	*status = 0;
  
  	if ((err = tda8261_read(state, &result)) < 0) {
  		pr_err("%s: I/O Error
  ", __func__);
  		return err;
  	}
  	if ((result >> 6) & 0x01) {
  		pr_debug("%s: Tuner Phase Locked
  ", __func__);
  		*status = 1;
  	}
  
  	return err;
  }
  
  static const u32 div_tab[] = { 2000, 1000,  500,  250,  125 }; /* kHz */
  static const u8  ref_div[] = { 0x00, 0x01, 0x02, 0x05, 0x07 };
  
  static int tda8261_get_state(struct dvb_frontend *fe,
  			     enum tuner_param param,
  			     struct tuner_state *tstate)
  {
  	struct tda8261_state *state = fe->tuner_priv;
  	int err = 0;
  
  	switch (param) {
  	case DVBFE_TUNER_FREQUENCY:
  		tstate->frequency = state->frequency;
  		break;
  	case DVBFE_TUNER_BANDWIDTH:
  		tstate->bandwidth = 40000000; /* FIXME! need to calculate Bandwidth */
  		break;
  	default:
  		pr_err("%s: Unknown parameter (param=%d)
  ", __func__, param);
  		err = -EINVAL;
  		break;
  	}
  
  	return err;
  }
  
  static int tda8261_set_state(struct dvb_frontend *fe,
  			     enum tuner_param param,
  			     struct tuner_state *tstate)
  {
  	struct tda8261_state *state = fe->tuner_priv;
  	const struct tda8261_config *config = state->config;
  	u32 frequency, N, status = 0;
  	u8 buf[4];
  	int err = 0;
  
  	if (param & DVBFE_TUNER_FREQUENCY) {
  		/**
  		 * N = Max VCO Frequency / Channel Spacing
  		 * Max VCO Frequency = VCO frequency + (channel spacing - 1)
  		 * (to account for half channel spacing on either side)
  		 */
  		frequency = tstate->frequency;
  		if ((frequency < 950000) || (frequency > 2150000)) {
  			pr_warn("%s: Frequency beyond limits, frequency=%d
  ", __func__, frequency);
  			return -EINVAL;
  		}
  		N = (frequency + (div_tab[config->step_size] - 1)) / div_tab[config->step_size];
  		pr_debug("%s: Step size=%d, Divider=%d, PG=0x%02x (%d)
  ",
  			__func__, config->step_size, div_tab[config->step_size], N, N);
  
  		buf[0] = (N >> 8) & 0xff;
  		buf[1] = N & 0xff;
  		buf[2] = (0x01 << 7) | ((ref_div[config->step_size] & 0x07) << 1);
  
  		if (frequency < 1450000)
  			buf[3] = 0x00;
  		else if (frequency < 2000000)
  			buf[3] = 0x40;
  		else if (frequency < 2150000)
  			buf[3] = 0x80;
  
  		/* Set params */
  		if ((err = tda8261_write(state, buf)) < 0) {
  			pr_err("%s: I/O Error
  ", __func__);
  			return err;
  		}
  		/* sleep for some time */
  		pr_debug("%s: Waiting to Phase LOCK
  ", __func__);
  		msleep(20);
  		/* check status */
  		if ((err = tda8261_get_status(fe, &status)) < 0) {
  			pr_err("%s: I/O Error
  ", __func__);
  			return err;
  		}
  		if (status == 1) {
  			pr_debug("%s: Tuner Phase locked: status=%d
  ", __func__, status);
  			state->frequency = frequency; /* cache successful state */
  		} else {
  			pr_debug("%s: No Phase lock: status=%d
  ", __func__, status);
  		}
  	} else {
  		pr_err("%s: Unknown parameter (param=%d)
  ", __func__, param);
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static int tda8261_release(struct dvb_frontend *fe)
  {
  	struct tda8261_state *state = fe->tuner_priv;
  
  	fe->tuner_priv = NULL;
  	kfree(state);
  	return 0;
  }
  
  static struct dvb_tuner_ops tda8261_ops = {
  
  	.info = {
  		.name		= "TDA8261",
  //		.tuner_name	= NULL,
  		.frequency_min	=  950000,
  		.frequency_max	= 2150000,
  		.frequency_step = 0
  	},
  
  	.set_state	= tda8261_set_state,
  	.get_state	= tda8261_get_state,
  	.get_status	= tda8261_get_status,
  	.release	= tda8261_release
  };
  
  struct dvb_frontend *tda8261_attach(struct dvb_frontend *fe,
  				    const struct tda8261_config *config,
  				    struct i2c_adapter *i2c)
  {
  	struct tda8261_state *state = NULL;
  
  	if ((state = kzalloc(sizeof (struct tda8261_state), GFP_KERNEL)) == NULL)
  		goto exit;
  
  	state->config		= config;
  	state->i2c		= i2c;
  	state->fe		= fe;
  	fe->tuner_priv		= state;
  	fe->ops.tuner_ops	= tda8261_ops;
  
  	fe->ops.tuner_ops.info.frequency_step = div_tab[config->step_size];
  //	fe->ops.tuner_ops.tuner_name	 = &config->buf;
  
  //	printk("%s: Attaching %s TDA8261 8PSK/QPSK tuner
  ",
  //		__func__, fe->ops.tuner_ops.tuner_name);
  	pr_info("%s: Attaching TDA8261 8PSK/QPSK tuner
  ", __func__);
  
  	return fe;
  
  exit:
  	kfree(state);
  	return NULL;
  }
  
  EXPORT_SYMBOL(tda8261_attach);
  
  MODULE_AUTHOR("Manu Abraham");
  MODULE_DESCRIPTION("TDA8261 8PSK/QPSK Tuner");
  MODULE_LICENSE("GPL");