/*
 * 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_CARD "Silicon Labs Si470x FM Radio Receiver"
#define DRIVER_DESC "I2C radio driver for Si470x FM Radio Receivers"
#define DRIVER_VERSION "1.0.2"

/* 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 / STC interrupt */
                radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDSIEN;
                radio->registers[SYSCONFIG1] |= SYSCONFIG1_STCIEN;
                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->capabilities = V4L2_CAP_HW_FREQ_SEEK |
                V4L2_CAP_TUNER | V4L2_CAP_RADIO;

        return 0;
}



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

/*
 * si470x_i2c_interrupt - interrupt handler
 */
static irqreturn_t si470x_i2c_interrupt(int irq, void *dev_id)
{
        struct si470x_device *radio = dev_id;
        unsigned char regnr;
        unsigned char blocknum;
        unsigned short bler; /* rds block errors */
        unsigned short rds;
        unsigned char tmpbuf[3];
        int retval = 0;

        /* check Seek/Tune Complete */
        retval = si470x_get_register(radio, STATUSRSSI);
        if (retval < 0)
                goto end;

        if (radio->registers[STATUSRSSI] & STATUSRSSI_STC)
                complete(&radio->completion);

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

        /* Update RDS registers */
        for (regnr = 1; regnr < RDS_REGISTER_NUM; regnr++) {
                retval = si470x_get_register(radio, STATUSRSSI + regnr);
                if (retval < 0)
                        goto end;
        }

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

        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);

end:
        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;
        }

        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_video;
        }
        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);

        /* mark Seek/Tune Complete Interrupt enabled */
        radio->stci_enabled = true;
        init_completion(&radio->completion);

        retval = request_threaded_irq(client->irq, NULL, 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);
        video_unregister_device(radio->videodev);
        kfree(radio);

        return 0;
}


#ifdef CONFIG_PM
/*
 * si470x_i2c_suspend - suspend the device
 */
static int si470x_i2c_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        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 device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        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;
}

static SIMPLE_DEV_PM_OPS(si470x_i2c_pm, si470x_i2c_suspend, si470x_i2c_resume);
#endif


/*
 * si470x_i2c_driver - i2c driver interface
 */
static struct i2c_driver si470x_i2c_driver = {
        .driver = {
                .name           = "si470x",
                .owner          = THIS_MODULE,
#ifdef CONFIG_PM
                .pm             = &si470x_i2c_pm,
#endif
        },
        .probe                  = si470x_i2c_probe,
        .remove                 = __devexit_p(si470x_i2c_remove),
        .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);