drivers/media/usb/au0828/au0828-i2c.c

   1 /*
   2  *  Driver for the Auvitek AU0828 USB bridge
   3  *
   4  *  Copyright (c) 2008 Steven Toth <stoth@linuxtv.org>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *
  15  *  GNU General Public License for more details.
  16  */
  17
  18 #include "au0828.h"
  19
  20 #include <linux/module.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/init.h>
  23 #include <linux/delay.h>
  24 #include <linux/io.h>
  25
  26 #include "media/tuner.h"
  27 #include <media/v4l2-common.h>
  28
  29 static int i2c_scan;
  30 module_param(i2c_scan, int, 0444);
  31 MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
  32
  33 #define I2C_WAIT_DELAY 25
  34 #define I2C_WAIT_RETRY 1000
  35
  36 static inline int i2c_slave_did_write_ack(struct i2c_adapter *i2c_adap)
  37 {
  38         struct au0828_dev *dev = i2c_adap->algo_data;
  39         return au0828_read(dev, AU0828_I2C_STATUS_201) &
  40                 AU0828_I2C_STATUS_NO_WRITE_ACK ? 0 : 1;
  41 }
  42
  43 static inline int i2c_slave_did_read_ack(struct i2c_adapter *i2c_adap)
  44 {
  45         struct au0828_dev *dev = i2c_adap->algo_data;
  46         return au0828_read(dev, AU0828_I2C_STATUS_201) &
  47                 AU0828_I2C_STATUS_NO_READ_ACK ? 0 : 1;
  48 }
  49
  50 static int i2c_wait_read_ack(struct i2c_adapter *i2c_adap)
  51 {
  52         int count;
  53
  54         for (count = 0; count < I2C_WAIT_RETRY; count++) {
  55                 if (!i2c_slave_did_read_ack(i2c_adap))
  56                         break;
  57                 udelay(I2C_WAIT_DELAY);
  58         }
  59
  60         if (I2C_WAIT_RETRY == count)
  61                 return 0;
  62
  63         return 1;
  64 }
  65
  66 static inline int i2c_is_read_busy(struct i2c_adapter *i2c_adap)
  67 {
  68         struct au0828_dev *dev = i2c_adap->algo_data;
  69         return au0828_read(dev, AU0828_I2C_STATUS_201) &
  70                 AU0828_I2C_STATUS_READ_DONE ? 0 : 1;
  71 }
  72
  73 static int i2c_wait_read_done(struct i2c_adapter *i2c_adap)
  74 {
  75         int count;
  76
  77         for (count = 0; count < I2C_WAIT_RETRY; count++) {
  78                 if (!i2c_is_read_busy(i2c_adap))
  79                         break;
  80                 udelay(I2C_WAIT_DELAY);
  81         }
  82
  83         if (I2C_WAIT_RETRY == count)
  84                 return 0;
  85
  86         return 1;
  87 }
  88
  89 static inline int i2c_is_write_done(struct i2c_adapter *i2c_adap)
  90 {
  91         struct au0828_dev *dev = i2c_adap->algo_data;
  92         return au0828_read(dev, AU0828_I2C_STATUS_201) &
  93                 AU0828_I2C_STATUS_WRITE_DONE ? 1 : 0;
  94 }
  95
  96 static int i2c_wait_write_done(struct i2c_adapter *i2c_adap)
  97 {
  98         int count;
  99
 100         for (count = 0; count < I2C_WAIT_RETRY; count++) {
 101                 if (i2c_is_write_done(i2c_adap))
 102                         break;
 103                 udelay(I2C_WAIT_DELAY);
 104         }
 105
 106         if (I2C_WAIT_RETRY == count)
 107                 return 0;
 108
 109         return 1;
 110 }
 111
 112 static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
 113 {
 114         struct au0828_dev *dev = i2c_adap->algo_data;
 115         return au0828_read(dev, AU0828_I2C_STATUS_201) &
 116                 AU0828_I2C_STATUS_BUSY ? 1 : 0;
 117 }
 118
 119 static int i2c_wait_done(struct i2c_adapter *i2c_adap)
 120 {
 121         int count;
 122
 123         for (count = 0; count < I2C_WAIT_RETRY; count++) {
 124                 if (!i2c_is_busy(i2c_adap))
 125                         break;
 126                 udelay(I2C_WAIT_DELAY);
 127         }
 128
 129         if (I2C_WAIT_RETRY == count)
 130                 return 0;
 131
 132         return 1;
 133 }
 134
 135 /* FIXME: Implement join handling correctly */
 136 static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
 137         const struct i2c_msg *msg, int joined_rlen)
 138 {
 139         int i, strobe = 0;
 140         struct au0828_dev *dev = i2c_adap->algo_data;
 141         u8 i2c_speed = dev->board.i2c_clk_divider;
 142
 143         dprintk(4, "%s()\n", __func__);
 144
 145         au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
 146
 147         if (((dev->board.tuner_type == TUNER_XC5000) ||
 148              (dev->board.tuner_type == TUNER_XC5000C)) &&
 149             (dev->board.tuner_addr == msg->addr)) {
 150                 /*
 151                  * Due to I2C clock stretch, we need to use a lower speed
 152                  * on xc5000 for commands. However, firmware transfer can
 153                  * speed up to 400 KHz.
 154                  */
 155                 if (msg->len == 64)
 156                         i2c_speed = AU0828_I2C_CLK_250KHZ;
 157                 else
 158                         i2c_speed = AU0828_I2C_CLK_20KHZ;
 159         }
 160         /* Set the I2C clock */
 161         au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202, i2c_speed);
 162
 163         /* Hardware needs 8 bit addresses */
 164         au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
 165
 166         dprintk(4, "SEND: %02x\n", msg->addr);
 167
 168         /* Deal with i2c_scan */
 169         if (msg->len == 0) {
 170                 /* The analog tuner detection code makes use of the SMBUS_QUICK
 171                    message (which involves a zero length i2c write).  To avoid
 172                    checking the status register when we didn't strobe out any
 173                    actual bytes to the bus, just do a read check.  This is
 174                    consistent with how I saw i2c device checking done in the
 175                    USB trace of the Windows driver */
 176                 au0828_write(dev, AU0828_I2C_TRIGGER_200,
 177                              AU0828_I2C_TRIGGER_READ);
 178
 179                 if (!i2c_wait_done(i2c_adap))
 180                         return -EIO;
 181
 182                 if (i2c_wait_read_ack(i2c_adap))
 183                         return -EIO;
 184
 185                 return 0;
 186         }
 187
 188         for (i = 0; i < msg->len;) {
 189
 190                 dprintk(4, " %02x\n", msg->buf[i]);
 191
 192                 au0828_write(dev, AU0828_I2C_WRITE_FIFO_205, msg->buf[i]);
 193
 194                 strobe++;
 195                 i++;
 196
 197                 if ((strobe >= 4) || (i >= msg->len)) {
 198
 199                         /* Strobe the byte into the bus */
 200                         if (i < msg->len)
 201                                 au0828_write(dev, AU0828_I2C_TRIGGER_200,
 202                                              AU0828_I2C_TRIGGER_WRITE |
 203                                              AU0828_I2C_TRIGGER_HOLD);
 204                         else
 205                                 au0828_write(dev, AU0828_I2C_TRIGGER_200,
 206                                              AU0828_I2C_TRIGGER_WRITE);
 207
 208                         /* Reset strobe trigger */
 209                         strobe = 0;
 210
 211                         if (!i2c_wait_write_done(i2c_adap))
 212                                 return -EIO;
 213
 214                 }
 215
 216         }
 217         if (!i2c_wait_done(i2c_adap))
 218                 return -EIO;
 219
 220         dprintk(4, "\n");
 221
 222         return msg->len;
 223 }
 224
 225 /* FIXME: Implement join handling correctly */
 226 static int i2c_readbytes(struct i2c_adapter *i2c_adap,
 227         const struct i2c_msg *msg, int joined)
 228 {
 229         struct au0828_dev *dev = i2c_adap->algo_data;
 230         u8 i2c_speed = dev->board.i2c_clk_divider;
 231         int i;
 232
 233         dprintk(4, "%s()\n", __func__);
 234
 235         au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
 236
 237         /*
 238          * Due to xc5000c clock stretch, we cannot use full speed at
 239          * readings from xc5000, as otherwise they'll fail.
 240          */
 241         if (((dev->board.tuner_type == TUNER_XC5000) ||
 242              (dev->board.tuner_type == TUNER_XC5000C)) &&
 243             (dev->board.tuner_addr == msg->addr))
 244                 i2c_speed = AU0828_I2C_CLK_20KHZ;
 245
 246         /* Set the I2C clock */
 247         au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202, i2c_speed);
 248
 249         /* Hardware needs 8 bit addresses */
 250         au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
 251
 252         dprintk(4, " RECV:\n");
 253
 254         /* Deal with i2c_scan */
 255         if (msg->len == 0) {
 256                 au0828_write(dev, AU0828_I2C_TRIGGER_200,
 257                              AU0828_I2C_TRIGGER_READ);
 258
 259                 if (i2c_wait_read_ack(i2c_adap))
 260                         return -EIO;
 261                 return 0;
 262         }
 263
 264         for (i = 0; i < msg->len;) {
 265
 266                 i++;
 267
 268                 if (i < msg->len)
 269                         au0828_write(dev, AU0828_I2C_TRIGGER_200,
 270                                      AU0828_I2C_TRIGGER_READ |
 271                                      AU0828_I2C_TRIGGER_HOLD);
 272                 else
 273                         au0828_write(dev, AU0828_I2C_TRIGGER_200,
 274                                      AU0828_I2C_TRIGGER_READ);
 275
 276                 if (!i2c_wait_read_done(i2c_adap))
 277                         return -EIO;
 278
 279                 msg->buf[i-1] = au0828_read(dev, AU0828_I2C_READ_FIFO_209) &
 280                         0xff;
 281
 282                 dprintk(4, " %02x\n", msg->buf[i-1]);
 283         }
 284         if (!i2c_wait_done(i2c_adap))
 285                 return -EIO;
 286
 287         dprintk(4, "\n");
 288
 289         return msg->len;
 290 }
 291
 292 static int i2c_xfer(struct i2c_adapter *i2c_adap,
 293                     struct i2c_msg *msgs, int num)
 294 {
 295         int i, retval = 0;
 296
 297         dprintk(4, "%s(num = %d)\n", __func__, num);
 298
 299         for (i = 0; i < num; i++) {
 300                 dprintk(4, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
 301                         __func__, num, msgs[i].addr, msgs[i].len);
 302                 if (msgs[i].flags & I2C_M_RD) {
 303                         /* read */
 304                         retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
 305                 } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
 306                            msgs[i].addr == msgs[i + 1].addr) {
 307                         /* write then read from same address */
 308                         retval = i2c_sendbytes(i2c_adap, &msgs[i],
 309                                                msgs[i + 1].len);
 310                         if (retval < 0)
 311                                 goto err;
 312                         i++;
 313                         retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
 314                 } else {
 315                         /* write */
 316                         retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
 317                 }
 318                 if (retval < 0)
 319                         goto err;
 320         }
 321         return num;
 322
 323 err:
 324         return retval;
 325 }
 326
 327 static u32 au0828_functionality(struct i2c_adapter *adap)
 328 {
 329         return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
 330 }
 331
 332 static const struct i2c_algorithm au0828_i2c_algo_template = {
 333         .master_xfer    = i2c_xfer,
 334         .functionality  = au0828_functionality,
 335 };
 336
 337 /* ----------------------------------------------------------------------- */
 338
 339 static const struct i2c_adapter au0828_i2c_adap_template = {
 340         .name              = KBUILD_MODNAME,
 341         .owner             = THIS_MODULE,
 342         .algo              = &au0828_i2c_algo_template,
 343 };
 344
 345 static const struct i2c_client au0828_i2c_client_template = {
 346         .name   = "au0828 internal",
 347 };
 348
 349 static char *i2c_devs[128] = {
 350         [0x8e >> 1] = "au8522",
 351         [0xa0 >> 1] = "eeprom",
 352         [0xc2 >> 1] = "tuner/xc5000",
 353 };
 354
 355 static void do_i2c_scan(char *name, struct i2c_client *c)
 356 {
 357         unsigned char buf;
 358         int i, rc;
 359
 360         for (i = 0; i < 128; i++) {
 361                 c->addr = i;
 362                 rc = i2c_master_recv(c, &buf, 0);
 363                 if (rc < 0)
 364                         continue;
 365                 pr_info("%s: i2c scan: found device @ 0x%x  [%s]\n",
 366                        name, i << 1, i2c_devs[i] ? i2c_devs[i] : "???");
 367         }
 368 }
 369
 370 /* init + register i2c adapter */
 371 int au0828_i2c_register(struct au0828_dev *dev)
 372 {
 373         dprintk(1, "%s()\n", __func__);
 374
 375         dev->i2c_adap = au0828_i2c_adap_template;
 376         dev->i2c_algo = au0828_i2c_algo_template;
 377         dev->i2c_client = au0828_i2c_client_template;
 378
 379         dev->i2c_adap.dev.parent = &dev->usbdev->dev;
 380
 381         strscpy(dev->i2c_adap.name, KBUILD_MODNAME,
 382                 sizeof(dev->i2c_adap.name));
 383
 384         dev->i2c_adap.algo = &dev->i2c_algo;
 385         dev->i2c_adap.algo_data = dev;
 386 #ifdef CONFIG_VIDEO_AU0828_V4L2
 387         i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
 388 #else
 389         i2c_set_adapdata(&dev->i2c_adap, dev);
 390 #endif
 391         i2c_add_adapter(&dev->i2c_adap);
 392
 393         dev->i2c_client.adapter = &dev->i2c_adap;
 394
 395         if (0 == dev->i2c_rc) {
 396                 pr_info("i2c bus registered\n");
 397                 if (i2c_scan)
 398                         do_i2c_scan(KBUILD_MODNAME, &dev->i2c_client);
 399         } else
 400                 pr_info("i2c bus register FAILED\n");
 401
 402         return dev->i2c_rc;
 403 }
 404
 405 int au0828_i2c_unregister(struct au0828_dev *dev)
 406 {
 407         i2c_del_adapter(&dev->i2c_adap);
 408         return 0;
 409 }
 410