/*
 * drivers/media/radio/si470x/radio-si470x-i2c.c
 *
 * I2C driver for radios with Silicon Labs Si470x FM Radio Receivers
 *
 * Copyright (c) 2009 Samsung Electronics Co.Ltd
 * Author: Joonyoung Shim <jy0922.shim@samsung.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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */


/* driver definitions */
#define DRIVER_AUTHOR "Joonyoung Shim <jy0922.shim@samsung.com>";
#define DRIVER_KERNEL_VERSION KERNEL_VERSION(1, 0, 1)
#define DRIVER_CARD "Silicon Labs Si470x FM Radio Receiver"
#define DRIVER_DESC "I2C radio driver for Si470x FM Radio Receivers"
#define DRIVER_VERSION "1.0.1"

/* kernel includes */
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/interrupt.h>

#include "radio-si470x.h"


/* I2C Device ID List */
static const struct i2c_device_id si470x_i2c_id[] = {
	/* Generic Entry */
	{ "si470x", 0 },
	/* Terminating entry */
	{ }
};
MODULE_DEVICE_TABLE(i2c, si470x_i2c_id);


/**************************************************************************
 * Module Parameters
 **************************************************************************/

/* Radio Nr */
static int radio_nr = -1;
module_param(radio_nr, int, 0444);
MODULE_PARM_DESC(radio_nr, "Radio Nr");

/* RDS buffer blocks */
static unsigned int rds_buf = 100;
module_param(rds_buf, uint, 0444);
MODULE_PARM_DESC(rds_buf, "RDS buffer entries: *100*");

/* RDS maximum block errors */
static unsigned short max_rds_errors = 1;
/* 0 means   0  errors requiring correction */
/* 1 means 1-2  errors requiring correction (used by original USBRadio.exe) */
/* 2 means 3-5  errors requiring correction */
/* 3 means   6+ errors or errors in checkword, correction not possible */
module_param(max_rds_errors, ushort, 0644);
MODULE_PARM_DESC(max_rds_errors, "RDS maximum block errors: *1*");


/**************************************************************************
 * I2C Definitions
 **************************************************************************/

/* Write starts with the upper byte of register 0x02 */
#define WRITE_REG_NUM		8
#define WRITE_INDEX(i)		(i + 0x02)

/* Read starts with the upper byte of register 0x0a */
#define READ_REG_NUM		RADIO_REGISTER_NUM
#define READ_INDEX(i)		((i + RADIO_REGISTER_NUM - 0x0a) % READ_REG_NUM)


/**************************************************************************
 * General Driver Functions - REGISTERs
 **************************************************************************/

/*
 * si470x_get_register - read register
 */
int si470x_get_register(struct si470x_device *radio, int regnr)
{
	u16 buf[READ_REG_NUM];
	struct i2c_msg msgs[1] = {
		{ radio->client->addr, I2C_M_RD, sizeof(u16) * READ_REG_NUM,
			(void *)buf },
	};

	if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
		return -EIO;

	radio->registers[regnr] = __be16_to_cpu(buf[READ_INDEX(regnr)]);

	return 0;
}


/*
 * si470x_set_register - write register
 */
int si470x_set_register(struct si470x_device *radio, int regnr)
{
	int i;
	u16 buf[WRITE_REG_NUM];
	struct i2c_msg msgs[1] = {
		{ radio->client->addr, 0, sizeof(u16) * WRITE_REG_NUM,
			(void *)buf },
	};

	for (i = 0; i < WRITE_REG_NUM; i++)
		buf[i] = __cpu_to_be16(radio->registers[WRITE_INDEX(i)]);

	if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
		return -EIO;

	return 0;
}


/**************************************************************************
 * General Driver Functions - ENTIRE REGISTERS
 **************************************************************************/

/*
 * si470x_get_all_registers - read entire registers
 */
static int si470x_get_all_registers(struct si470x_device *radio)
{
	int i;
	u16 buf[READ_REG_NUM];
	struct i2c_msg msgs[1] = {
		{ radio->client->addr, I2C_M_RD, sizeof(u16) * READ_REG_NUM,
			(void *)buf },
	};

	if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
		return -EIO;

	for (i = 0; i < READ_REG_NUM; i++)
		radio->registers[i] = __be16_to_cpu(buf[READ_INDEX(i)]);

	return 0;
}


/**************************************************************************
 * General Driver Functions - DISCONNECT_CHECK
 **************************************************************************/

/*
 * si470x_disconnect_check - check whether radio disconnects
 */
int si470x_disconnect_check(struct si470x_device *radio)
{
	return 0;
}


/**************************************************************************
 * File Operations Interface
 **************************************************************************/

/*
 * si470x_fops_open - file open
 */
int si470x_fops_open(struct file *file)
{
	struct si470x_device *radio = video_drvdata(file);
	int retval = 0;

	mutex_lock(&radio->lock);
	radio->users++;

	if (radio->users == 1) {
		/* start radio */
		retval = si470x_start(radio);
		if (retval < 0)
			goto done;

		/* enable RDS interrupt */
		radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDSIEN;
		radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_GPIO2;
		radio->registers[SYSCONFIG1] |= 0x1 << 2;
		retval = si470x_set_register(radio, SYSCONFIG1);
	}

done:
	mutex_unlock(&radio->lock);
	return retval;
}


/*
 * si470x_fops_release - file release
 */
int si470x_fops_release(struct file *file)
{
	struct si470x_device *radio = video_drvdata(file);
	int retval = 0;

	/* safety check */
	if (!radio)
		return -ENODEV;

	mutex_lock(&radio->lock);
	radio->users--;
	if (radio->users == 0)
		/* stop radio */
		retval = si470x_stop(radio);

	mutex_unlock(&radio->lock);

	return retval;
}


/**************************************************************************
 * Video4Linux Interface
 **************************************************************************/

/*
 * si470x_vidioc_querycap - query device capabilities
 */
int si470x_vidioc_querycap(struct file *file, void *priv,
		struct v4l2_capability *capability)
{
	strlcpy(capability->driver, DRIVER_NAME, sizeof(capability->driver));
	strlcpy(capability->card, DRIVER_CARD, sizeof(capability->card));
	capability->version = DRIVER_KERNEL_VERSION;
	capability->capabilities = V4L2_CAP_HW_FREQ_SEEK |
		V4L2_CAP_TUNER | V4L2_CAP_RADIO;

	return 0;
}


/**************************************************************************
 * I2C Interface
 **************************************************************************/

/*
 * si470x_i2c_interrupt_work - rds processing function
 */
static void si470x_i2c_interrupt_work(struct work_struct *work)
{
	struct si470x_device *radio = container_of(work,
			struct si470x_device, radio_work);
	unsigned char regnr;
	unsigned char blocknum;
	unsigned short bler; /* rds block errors */
	unsigned short rds;
	unsigned char tmpbuf[3];
	int retval = 0;

	/* safety checks */
	if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
		return;

	/* Update RDS registers */
	for (regnr = 0; regnr < RDS_REGISTER_NUM; regnr++) {
		retval = si470x_get_register(radio, STATUSRSSI + regnr);
		if (retval < 0)
			return;
	}

	/* get rds blocks */
	if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0)
		/* No RDS group ready, better luck next time */
		return;

	for (blocknum = 0; blocknum < 4; blocknum++) {
		switch (blocknum) {
		default:
			bler = (radio->registers[STATUSRSSI] &
					STATUSRSSI_BLERA) >> 9;
			rds = radio->registers[RDSA];
			break;
		case 1:
			bler = (radio->registers[READCHAN] &
					READCHAN_BLERB) >> 14;
			rds = radio->registers[RDSB];
			break;
		case 2:
			bler = (radio->registers[READCHAN] &
					READCHAN_BLERC) >> 12;
			rds = radio->registers[RDSC];
			break;
		case 3:
			bler = (radio->registers[READCHAN] &
					READCHAN_BLERD) >> 10;
			rds = radio->registers[RDSD];
			break;
		};

		/* Fill the V4L2 RDS buffer */
		put_unaligned_le16(rds, &tmpbuf);
		tmpbuf[2] = blocknum;		/* offset name */
		tmpbuf[2] |= blocknum << 3;	/* received offset */
		if (bler > max_rds_errors)
			tmpbuf[2] |= 0x80;	/* uncorrectable errors */
		else if (bler > 0)
			tmpbuf[2] |= 0x40;	/* corrected error(s) */

		/* copy RDS block to internal buffer */
		memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
		radio->wr_index += 3;

		/* wrap write pointer */
		if (radio->wr_index >= radio->buf_size)
			radio->wr_index = 0;

		/* check for overflow */
		if (radio->wr_index == radio->rd_index) {
			/* increment and wrap read pointer */
			radio->rd_index += 3;
			if (radio->rd_index >= radio->buf_size)
				radio->rd_index = 0;
		}
	}

	if (radio->wr_index != radio->rd_index)
		wake_up_interruptible(&radio->read_queue);
}


/*
 * si470x_i2c_interrupt - interrupt handler
 */
static irqreturn_t si470x_i2c_interrupt(int irq, void *dev_id)
{
	struct si470x_device *radio = dev_id;

	if (!work_pending(&radio->radio_work))
		schedule_work(&radio->radio_work);

	return IRQ_HANDLED;
}


/*
 * si470x_i2c_probe - probe for the device
 */
static int __devinit si470x_i2c_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
{
	struct si470x_device *radio;
	int retval = 0;
	unsigned char version_warning = 0;

	/* private data allocation and initialization */
	radio = kzalloc(sizeof(struct si470x_device), GFP_KERNEL);
	if (!radio) {
		retval = -ENOMEM;
		goto err_initial;
	}

	INIT_WORK(&radio->radio_work, si470x_i2c_interrupt_work);
	radio->users = 0;
	radio->client = client;
	mutex_init(&radio->lock);

	/* video device allocation and initialization */
	radio->videodev = video_device_alloc();
	if (!radio->videodev) {
		retval = -ENOMEM;
		goto err_radio;
	}
	memcpy(radio->videodev, &si470x_viddev_template,
			sizeof(si470x_viddev_template));
	video_set_drvdata(radio->videodev, radio);

	/* power up : need 110ms */
	radio->registers[POWERCFG] = POWERCFG_ENABLE;
	if (si470x_set_register(radio, POWERCFG) < 0) {
		retval = -EIO;
		goto err_all;
	}
	msleep(110);

	/* get device and chip versions */
	if (si470x_get_all_registers(radio) < 0) {
		retval = -EIO;
		goto err_video;
	}
	dev_info(&client->dev, "DeviceID=0x%4.4hx ChipID=0x%4.4hx\n",
			radio->registers[DEVICEID], radio->registers[CHIPID]);
	if ((radio->registers[CHIPID] & CHIPID_FIRMWARE) < RADIO_FW_VERSION) {
		dev_warn(&client->dev,
			"This driver is known to work with "
			"firmware version %hu,\n", RADIO_FW_VERSION);
		dev_warn(&client->dev,
			"but the device has firmware version %hu.\n",
			radio->registers[CHIPID] & CHIPID_FIRMWARE);
		version_warning = 1;
	}

	/* give out version warning */
	if (version_warning == 1) {
		dev_warn(&client->dev,
			"If you have some trouble using this driver,\n");
		dev_warn(&client->dev,
			"please report to V4L ML at "
			"linux-media@vger.kernel.org\n");
	}

	/* set initial frequency */
	si470x_set_freq(radio, 87.5 * FREQ_MUL); /* available in all regions */

	/* rds buffer allocation */
	radio->buf_size = rds_buf * 3;
	radio->buffer = kmalloc(radio->buf_size, GFP_KERNEL);
	if (!radio->buffer) {
		retval = -EIO;
		goto err_video;
	}

	/* rds buffer configuration */
	radio->wr_index = 0;
	radio->rd_index = 0;
	init_waitqueue_head(&radio->read_queue);

	retval = request_irq(client->irq, si470x_i2c_interrupt,
			IRQF_TRIGGER_FALLING, DRIVER_NAME, radio);
	if (retval) {
		dev_err(&client->dev, "Failed to register interrupt\n");
		goto err_rds;
	}

	/* register video device */
	retval = video_register_device(radio->videodev, VFL_TYPE_RADIO,
			radio_nr);
	if (retval) {
		dev_warn(&client->dev, "Could not register video device\n");
		goto err_all;
	}
	i2c_set_clientdata(client, radio);

	return 0;
err_all:
	free_irq(client->irq, radio);
err_rds:
	kfree(radio->buffer);
err_video:
	video_device_release(radio->videodev);
err_radio:
	kfree(radio);
err_initial:
	return retval;
}


/*
 * si470x_i2c_remove - remove the device
 */
static __devexit int si470x_i2c_remove(struct i2c_client *client)
{
	struct si470x_device *radio = i2c_get_clientdata(client);

	free_irq(client->irq, radio);
	cancel_work_sync(&radio->radio_work);
	video_unregister_device(radio->videodev);
	kfree(radio);
	i2c_set_clientdata(client, NULL);

	return 0;
}


#ifdef CONFIG_PM
/*
 * si470x_i2c_suspend - suspend the device
 */
static int si470x_i2c_suspend(struct i2c_client *client, pm_message_t mesg)
{
	struct si470x_device *radio = i2c_get_clientdata(client);

	/* power down */
	radio->registers[POWERCFG] |= POWERCFG_DISABLE;
	if (si470x_set_register(radio, POWERCFG) < 0)
		return -EIO;

	return 0;
}


/*
 * si470x_i2c_resume - resume the device
 */
static int si470x_i2c_resume(struct i2c_client *client)
{
	struct si470x_device *radio = i2c_get_clientdata(client);

	/* power up : need 110ms */
	radio->registers[POWERCFG] |= POWERCFG_ENABLE;
	if (si470x_set_register(radio, POWERCFG) < 0)
		return -EIO;
	msleep(110);

	return 0;
}
#else
#define si470x_i2c_suspend	NULL
#define si470x_i2c_resume	NULL
#endif


/*
 * si470x_i2c_driver - i2c driver interface
 */
static struct i2c_driver si470x_i2c_driver = {
	.driver = {
		.name		= "si470x",
		.owner		= THIS_MODULE,
	},
	.probe			= si470x_i2c_probe,
	.remove			= __devexit_p(si470x_i2c_remove),
	.suspend		= si470x_i2c_suspend,
	.resume			= si470x_i2c_resume,
	.id_table		= si470x_i2c_id,
};


/**************************************************************************
 * Module Interface
 **************************************************************************/

/*
 * si470x_i2c_init - module init
 */
static int __init si470x_i2c_init(void)
{
	printk(KERN_INFO DRIVER_DESC ", Version " DRIVER_VERSION "\n");
	return i2c_add_driver(&si470x_i2c_driver);
}


/*
 * si470x_i2c_exit - module exit
 */
static void __exit si470x_i2c_exit(void)
{
	i2c_del_driver(&si470x_i2c_driver);
}


module_init(si470x_i2c_init);
module_exit(si470x_i2c_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_VERSION(DRIVER_VERSION);