radio-si470x-i2c.c

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/*
 * 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 <[email protected]>
 *
 * 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 <[email protected]>";
#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] = {
        {
            .addr = radio->client->addr,
            .flags = I2C_M_RD,
            .len = sizeof(u16) * READ_REG_NUM,
            .buf = (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] = {
        {
            .addr = radio->client->addr,
            .len = sizeof(u16) * WRITE_REG_NUM,
            .buf = (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] = {
        {
            .addr = radio->client->addr,
            .flags = I2C_M_RD,
            .len = sizeof(u16) * READ_REG_NUM,
            .buf = (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;
}



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

/*
 * si470x_fops_open - file open
 */
int si470x_fops_open(struct file *file)
{
    struct si470x_device *radio = video_drvdata(file);
    int retval = v4l2_fh_open(file);

    if (retval)
        return retval;

    if (v4l2_fh_is_singular_file(file)) {
        /* 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:
    if (retval)
        v4l2_fh_release(file);
    return retval;
}


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

    if (v4l2_fh_is_singular_file(file))
        /* stop radio */
        si470x_stop(radio);

    return v4l2_fh_release(file);
}



/**************************************************************************
 * 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->device_caps = V4L2_CAP_HW_FREQ_SEEK | V4L2_CAP_READWRITE |
        V4L2_CAP_TUNER | V4L2_CAP_RADIO | V4L2_CAP_RDS_CAPTURE;
    capability->capabilities = capability->device_caps | V4L2_CAP_DEVICE_CAPS;

    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->client = client;
    radio->band = 1; /* Default to 76 - 108 MHz */
    mutex_init(&radio->lock);
    init_completion(&radio->completion);

    /* video device initialization */
    radio->videodev = 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_radio;
    }
    msleep(110);

    /* get device and chip versions */
    if (si470x_get_all_registers(radio) < 0) {
        retval = -EIO;
        goto err_radio;
    }
    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 "
            "[email protected]\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_radio;
    }

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

    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_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_i2c_driver(si470x_i2c_driver);

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