linux/drivers/media/radio/si470x/radio-si470x-i2c.c
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   1/*
   2 * drivers/media/radio/si470x/radio-si470x-i2c.c
   3 *
   4 * I2C driver for radios with Silicon Labs Si470x FM Radio Receivers
   5 *
   6 * Copyright (c) 2009 Samsung Electronics Co.Ltd
   7 * Author: Joonyoung Shim <jy0922.shim@samsung.com>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License as published by
  11 * the Free Software Foundation; either version 2 of the License, or
  12 * (at your option) any later version.
  13 *
  14 * This program is distributed in the hope that it will be useful,
  15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 * GNU General Public License for more details.
  18 *
  19 * You should have received a copy of the GNU General Public License
  20 * along with this program; if not, write to the Free Software
  21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22 */
  23
  24
  25/* driver definitions */
  26#define DRIVER_AUTHOR "Joonyoung Shim <jy0922.shim@samsung.com>";
  27#define DRIVER_KERNEL_VERSION KERNEL_VERSION(1, 0, 1)
  28#define DRIVER_CARD "Silicon Labs Si470x FM Radio Receiver"
  29#define DRIVER_DESC "I2C radio driver for Si470x FM Radio Receivers"
  30#define DRIVER_VERSION "1.0.1"
  31
  32/* kernel includes */
  33#include <linux/i2c.h>
  34#include <linux/slab.h>
  35#include <linux/delay.h>
  36#include <linux/interrupt.h>
  37
  38#include "radio-si470x.h"
  39
  40
  41/* I2C Device ID List */
  42static const struct i2c_device_id si470x_i2c_id[] = {
  43        /* Generic Entry */
  44        { "si470x", 0 },
  45        /* Terminating entry */
  46        { }
  47};
  48MODULE_DEVICE_TABLE(i2c, si470x_i2c_id);
  49
  50
  51
  52/**************************************************************************
  53 * Module Parameters
  54 **************************************************************************/
  55
  56/* Radio Nr */
  57static int radio_nr = -1;
  58module_param(radio_nr, int, 0444);
  59MODULE_PARM_DESC(radio_nr, "Radio Nr");
  60
  61/* RDS buffer blocks */
  62static unsigned int rds_buf = 100;
  63module_param(rds_buf, uint, 0444);
  64MODULE_PARM_DESC(rds_buf, "RDS buffer entries: *100*");
  65
  66/* RDS maximum block errors */
  67static unsigned short max_rds_errors = 1;
  68/* 0 means   0  errors requiring correction */
  69/* 1 means 1-2  errors requiring correction (used by original USBRadio.exe) */
  70/* 2 means 3-5  errors requiring correction */
  71/* 3 means   6+ errors or errors in checkword, correction not possible */
  72module_param(max_rds_errors, ushort, 0644);
  73MODULE_PARM_DESC(max_rds_errors, "RDS maximum block errors: *1*");
  74
  75
  76
  77/**************************************************************************
  78 * I2C Definitions
  79 **************************************************************************/
  80
  81/* Write starts with the upper byte of register 0x02 */
  82#define WRITE_REG_NUM           8
  83#define WRITE_INDEX(i)          (i + 0x02)
  84
  85/* Read starts with the upper byte of register 0x0a */
  86#define READ_REG_NUM            RADIO_REGISTER_NUM
  87#define READ_INDEX(i)           ((i + RADIO_REGISTER_NUM - 0x0a) % READ_REG_NUM)
  88
  89
  90
  91/**************************************************************************
  92 * General Driver Functions - REGISTERs
  93 **************************************************************************/
  94
  95/*
  96 * si470x_get_register - read register
  97 */
  98int si470x_get_register(struct si470x_device *radio, int regnr)
  99{
 100        u16 buf[READ_REG_NUM];
 101        struct i2c_msg msgs[1] = {
 102                { radio->client->addr, I2C_M_RD, sizeof(u16) * READ_REG_NUM,
 103                        (void *)buf },
 104        };
 105
 106        if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
 107                return -EIO;
 108
 109        radio->registers[regnr] = __be16_to_cpu(buf[READ_INDEX(regnr)]);
 110
 111        return 0;
 112}
 113
 114
 115/*
 116 * si470x_set_register - write register
 117 */
 118int si470x_set_register(struct si470x_device *radio, int regnr)
 119{
 120        int i;
 121        u16 buf[WRITE_REG_NUM];
 122        struct i2c_msg msgs[1] = {
 123                { radio->client->addr, 0, sizeof(u16) * WRITE_REG_NUM,
 124                        (void *)buf },
 125        };
 126
 127        for (i = 0; i < WRITE_REG_NUM; i++)
 128                buf[i] = __cpu_to_be16(radio->registers[WRITE_INDEX(i)]);
 129
 130        if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
 131                return -EIO;
 132
 133        return 0;
 134}
 135
 136
 137
 138/**************************************************************************
 139 * General Driver Functions - ENTIRE REGISTERS
 140 **************************************************************************/
 141
 142/*
 143 * si470x_get_all_registers - read entire registers
 144 */
 145static int si470x_get_all_registers(struct si470x_device *radio)
 146{
 147        int i;
 148        u16 buf[READ_REG_NUM];
 149        struct i2c_msg msgs[1] = {
 150                { radio->client->addr, I2C_M_RD, sizeof(u16) * READ_REG_NUM,
 151                        (void *)buf },
 152        };
 153
 154        if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
 155                return -EIO;
 156
 157        for (i = 0; i < READ_REG_NUM; i++)
 158                radio->registers[i] = __be16_to_cpu(buf[READ_INDEX(i)]);
 159
 160        return 0;
 161}
 162
 163
 164
 165/**************************************************************************
 166 * General Driver Functions - DISCONNECT_CHECK
 167 **************************************************************************/
 168
 169/*
 170 * si470x_disconnect_check - check whether radio disconnects
 171 */
 172int si470x_disconnect_check(struct si470x_device *radio)
 173{
 174        return 0;
 175}
 176
 177
 178
 179/**************************************************************************
 180 * File Operations Interface
 181 **************************************************************************/
 182
 183/*
 184 * si470x_fops_open - file open
 185 */
 186int si470x_fops_open(struct file *file)
 187{
 188        struct si470x_device *radio = video_drvdata(file);
 189        int retval = 0;
 190
 191        mutex_lock(&radio->lock);
 192        radio->users++;
 193
 194        if (radio->users == 1) {
 195                /* start radio */
 196                retval = si470x_start(radio);
 197                if (retval < 0)
 198                        goto done;
 199
 200                /* enable RDS interrupt */
 201                radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDSIEN;
 202                radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_GPIO2;
 203                radio->registers[SYSCONFIG1] |= 0x1 << 2;
 204                retval = si470x_set_register(radio, SYSCONFIG1);
 205        }
 206
 207done:
 208        mutex_unlock(&radio->lock);
 209        return retval;
 210}
 211
 212
 213/*
 214 * si470x_fops_release - file release
 215 */
 216int si470x_fops_release(struct file *file)
 217{
 218        struct si470x_device *radio = video_drvdata(file);
 219        int retval = 0;
 220
 221        /* safety check */
 222        if (!radio)
 223                return -ENODEV;
 224
 225        mutex_lock(&radio->lock);
 226        radio->users--;
 227        if (radio->users == 0)
 228                /* stop radio */
 229                retval = si470x_stop(radio);
 230
 231        mutex_unlock(&radio->lock);
 232
 233        return retval;
 234}
 235
 236
 237
 238/**************************************************************************
 239 * Video4Linux Interface
 240 **************************************************************************/
 241
 242/*
 243 * si470x_vidioc_querycap - query device capabilities
 244 */
 245int si470x_vidioc_querycap(struct file *file, void *priv,
 246                struct v4l2_capability *capability)
 247{
 248        strlcpy(capability->driver, DRIVER_NAME, sizeof(capability->driver));
 249        strlcpy(capability->card, DRIVER_CARD, sizeof(capability->card));
 250        capability->version = DRIVER_KERNEL_VERSION;
 251        capability->capabilities = V4L2_CAP_HW_FREQ_SEEK |
 252                V4L2_CAP_TUNER | V4L2_CAP_RADIO;
 253
 254        return 0;
 255}
 256
 257
 258
 259/**************************************************************************
 260 * I2C Interface
 261 **************************************************************************/
 262
 263/*
 264 * si470x_i2c_interrupt_work - rds processing function
 265 */
 266static void si470x_i2c_interrupt_work(struct work_struct *work)
 267{
 268        struct si470x_device *radio = container_of(work,
 269                        struct si470x_device, radio_work);
 270        unsigned char regnr;
 271        unsigned char blocknum;
 272        unsigned short bler; /* rds block errors */
 273        unsigned short rds;
 274        unsigned char tmpbuf[3];
 275        int retval = 0;
 276
 277        /* safety checks */
 278        if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
 279                return;
 280
 281        /* Update RDS registers */
 282        for (regnr = 0; regnr < RDS_REGISTER_NUM; regnr++) {
 283                retval = si470x_get_register(radio, STATUSRSSI + regnr);
 284                if (retval < 0)
 285                        return;
 286        }
 287
 288        /* get rds blocks */
 289        if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0)
 290                /* No RDS group ready, better luck next time */
 291                return;
 292
 293        for (blocknum = 0; blocknum < 4; blocknum++) {
 294                switch (blocknum) {
 295                default:
 296                        bler = (radio->registers[STATUSRSSI] &
 297                                        STATUSRSSI_BLERA) >> 9;
 298                        rds = radio->registers[RDSA];
 299                        break;
 300                case 1:
 301                        bler = (radio->registers[READCHAN] &
 302                                        READCHAN_BLERB) >> 14;
 303                        rds = radio->registers[RDSB];
 304                        break;
 305                case 2:
 306                        bler = (radio->registers[READCHAN] &
 307                                        READCHAN_BLERC) >> 12;
 308                        rds = radio->registers[RDSC];
 309                        break;
 310                case 3:
 311                        bler = (radio->registers[READCHAN] &
 312                                        READCHAN_BLERD) >> 10;
 313                        rds = radio->registers[RDSD];
 314                        break;
 315                };
 316
 317                /* Fill the V4L2 RDS buffer */
 318                put_unaligned_le16(rds, &tmpbuf);
 319                tmpbuf[2] = blocknum;           /* offset name */
 320                tmpbuf[2] |= blocknum << 3;     /* received offset */
 321                if (bler > max_rds_errors)
 322                        tmpbuf[2] |= 0x80;      /* uncorrectable errors */
 323                else if (bler > 0)
 324                        tmpbuf[2] |= 0x40;      /* corrected error(s) */
 325
 326                /* copy RDS block to internal buffer */
 327                memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
 328                radio->wr_index += 3;
 329
 330                /* wrap write pointer */
 331                if (radio->wr_index >= radio->buf_size)
 332                        radio->wr_index = 0;
 333
 334                /* check for overflow */
 335                if (radio->wr_index == radio->rd_index) {
 336                        /* increment and wrap read pointer */
 337                        radio->rd_index += 3;
 338                        if (radio->rd_index >= radio->buf_size)
 339                                radio->rd_index = 0;
 340                }
 341        }
 342
 343        if (radio->wr_index != radio->rd_index)
 344                wake_up_interruptible(&radio->read_queue);
 345}
 346
 347
 348/*
 349 * si470x_i2c_interrupt - interrupt handler
 350 */
 351static irqreturn_t si470x_i2c_interrupt(int irq, void *dev_id)
 352{
 353        struct si470x_device *radio = dev_id;
 354
 355        if (!work_pending(&radio->radio_work))
 356                schedule_work(&radio->radio_work);
 357
 358        return IRQ_HANDLED;
 359}
 360
 361
 362/*
 363 * si470x_i2c_probe - probe for the device
 364 */
 365static int __devinit si470x_i2c_probe(struct i2c_client *client,
 366                const struct i2c_device_id *id)
 367{
 368        struct si470x_device *radio;
 369        int retval = 0;
 370        unsigned char version_warning = 0;
 371
 372        /* private data allocation and initialization */
 373        radio = kzalloc(sizeof(struct si470x_device), GFP_KERNEL);
 374        if (!radio) {
 375                retval = -ENOMEM;
 376                goto err_initial;
 377        }
 378
 379        INIT_WORK(&radio->radio_work, si470x_i2c_interrupt_work);
 380        radio->users = 0;
 381        radio->client = client;
 382        mutex_init(&radio->lock);
 383
 384        /* video device allocation and initialization */
 385        radio->videodev = video_device_alloc();
 386        if (!radio->videodev) {
 387                retval = -ENOMEM;
 388                goto err_radio;
 389        }
 390        memcpy(radio->videodev, &si470x_viddev_template,
 391                        sizeof(si470x_viddev_template));
 392        video_set_drvdata(radio->videodev, radio);
 393
 394        /* power up : need 110ms */
 395        radio->registers[POWERCFG] = POWERCFG_ENABLE;
 396        if (si470x_set_register(radio, POWERCFG) < 0) {
 397                retval = -EIO;
 398                goto err_all;
 399        }
 400        msleep(110);
 401
 402        /* get device and chip versions */
 403        if (si470x_get_all_registers(radio) < 0) {
 404                retval = -EIO;
 405                goto err_video;
 406        }
 407        dev_info(&client->dev, "DeviceID=0x%4.4hx ChipID=0x%4.4hx\n",
 408                        radio->registers[DEVICEID], radio->registers[CHIPID]);
 409        if ((radio->registers[CHIPID] & CHIPID_FIRMWARE) < RADIO_FW_VERSION) {
 410                dev_warn(&client->dev,
 411                        "This driver is known to work with "
 412                        "firmware version %hu,\n", RADIO_FW_VERSION);
 413                dev_warn(&client->dev,
 414                        "but the device has firmware version %hu.\n",
 415                        radio->registers[CHIPID] & CHIPID_FIRMWARE);
 416                version_warning = 1;
 417        }
 418
 419        /* give out version warning */
 420        if (version_warning == 1) {
 421                dev_warn(&client->dev,
 422                        "If you have some trouble using this driver,\n");
 423                dev_warn(&client->dev,
 424                        "please report to V4L ML at "
 425                        "linux-media@vger.kernel.org\n");
 426        }
 427
 428        /* set initial frequency */
 429        si470x_set_freq(radio, 87.5 * FREQ_MUL); /* available in all regions */
 430
 431        /* rds buffer allocation */
 432        radio->buf_size = rds_buf * 3;
 433        radio->buffer = kmalloc(radio->buf_size, GFP_KERNEL);
 434        if (!radio->buffer) {
 435                retval = -EIO;
 436                goto err_video;
 437        }
 438
 439        /* rds buffer configuration */
 440        radio->wr_index = 0;
 441        radio->rd_index = 0;
 442        init_waitqueue_head(&radio->read_queue);
 443
 444        retval = request_irq(client->irq, si470x_i2c_interrupt,
 445                        IRQF_TRIGGER_FALLING, DRIVER_NAME, radio);
 446        if (retval) {
 447                dev_err(&client->dev, "Failed to register interrupt\n");
 448                goto err_rds;
 449        }
 450
 451        /* register video device */
 452        retval = video_register_device(radio->videodev, VFL_TYPE_RADIO,
 453                        radio_nr);
 454        if (retval) {
 455                dev_warn(&client->dev, "Could not register video device\n");
 456                goto err_all;
 457        }
 458        i2c_set_clientdata(client, radio);
 459
 460        return 0;
 461err_all:
 462        free_irq(client->irq, radio);
 463err_rds:
 464        kfree(radio->buffer);
 465err_video:
 466        video_device_release(radio->videodev);
 467err_radio:
 468        kfree(radio);
 469err_initial:
 470        return retval;
 471}
 472
 473
 474/*
 475 * si470x_i2c_remove - remove the device
 476 */
 477static __devexit int si470x_i2c_remove(struct i2c_client *client)
 478{
 479        struct si470x_device *radio = i2c_get_clientdata(client);
 480
 481        free_irq(client->irq, radio);
 482        cancel_work_sync(&radio->radio_work);
 483        video_unregister_device(radio->videodev);
 484        kfree(radio);
 485
 486        return 0;
 487}
 488
 489
 490#ifdef CONFIG_PM
 491/*
 492 * si470x_i2c_suspend - suspend the device
 493 */
 494static int si470x_i2c_suspend(struct i2c_client *client, pm_message_t mesg)
 495{
 496        struct si470x_device *radio = i2c_get_clientdata(client);
 497
 498        /* power down */
 499        radio->registers[POWERCFG] |= POWERCFG_DISABLE;
 500        if (si470x_set_register(radio, POWERCFG) < 0)
 501                return -EIO;
 502
 503        return 0;
 504}
 505
 506
 507/*
 508 * si470x_i2c_resume - resume the device
 509 */
 510static int si470x_i2c_resume(struct i2c_client *client)
 511{
 512        struct si470x_device *radio = i2c_get_clientdata(client);
 513
 514        /* power up : need 110ms */
 515        radio->registers[POWERCFG] |= POWERCFG_ENABLE;
 516        if (si470x_set_register(radio, POWERCFG) < 0)
 517                return -EIO;
 518        msleep(110);
 519
 520        return 0;
 521}
 522#else
 523#define si470x_i2c_suspend      NULL
 524#define si470x_i2c_resume       NULL
 525#endif
 526
 527
 528/*
 529 * si470x_i2c_driver - i2c driver interface
 530 */
 531static struct i2c_driver si470x_i2c_driver = {
 532        .driver = {
 533                .name           = "si470x",
 534                .owner          = THIS_MODULE,
 535        },
 536        .probe                  = si470x_i2c_probe,
 537        .remove                 = __devexit_p(si470x_i2c_remove),
 538        .suspend                = si470x_i2c_suspend,
 539        .resume                 = si470x_i2c_resume,
 540        .id_table               = si470x_i2c_id,
 541};
 542
 543
 544
 545/**************************************************************************
 546 * Module Interface
 547 **************************************************************************/
 548
 549/*
 550 * si470x_i2c_init - module init
 551 */
 552static int __init si470x_i2c_init(void)
 553{
 554        printk(KERN_INFO DRIVER_DESC ", Version " DRIVER_VERSION "\n");
 555        return i2c_add_driver(&si470x_i2c_driver);
 556}
 557
 558
 559/*
 560 * si470x_i2c_exit - module exit
 561 */
 562static void __exit si470x_i2c_exit(void)
 563{
 564        i2c_del_driver(&si470x_i2c_driver);
 565}
 566
 567
 568module_init(si470x_i2c_init);
 569module_exit(si470x_i2c_exit);
 570
 571MODULE_LICENSE("GPL");
 572MODULE_AUTHOR(DRIVER_AUTHOR);
 573MODULE_DESCRIPTION(DRIVER_DESC);
 574MODULE_VERSION(DRIVER_VERSION);
 575