drivers/media/pci/cx25821/cx25821-i2c.c

   1 /*
   2  *  Driver for the Conexant CX25821 PCIe bridge
   3  *
   4  *  Copyright (C) 2009 Conexant Systems Inc.
   5  *  Authors  <shu.lin@conexant.com>, <hiep.huynh@conexant.com>
   6  *      Based on Steven Toth <stoth@linuxtv.org> cx23885 driver
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *
  17  *  GNU General Public License for more details.
  18  */
  19
  20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22 #include <linux/module.h>
  23 #include <linux/i2c.h>
  24 #include "cx25821.h"
  25
  26 static unsigned int i2c_debug;
  27 module_param(i2c_debug, int, 0644);
  28 MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
  29
  30 static unsigned int i2c_scan;
  31 module_param(i2c_scan, int, 0444);
  32 MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
  33
  34 #define dprintk(level, fmt, arg...)                                     \
  35 do {                                                                    \
  36         if (i2c_debug >= level)                                         \
  37                 printk(KERN_DEBUG "%s/0: " fmt, dev->name, ##arg);      \
  38 } while (0)
  39
  40 #define I2C_WAIT_DELAY 32
  41 #define I2C_WAIT_RETRY 64
  42
  43 #define I2C_EXTEND  (1 << 3)
  44 #define I2C_NOSTOP  (1 << 4)
  45
  46 static inline int i2c_slave_did_ack(struct i2c_adapter *i2c_adap)
  47 {
  48         struct cx25821_i2c *bus = i2c_adap->algo_data;
  49         struct cx25821_dev *dev = bus->dev;
  50         return cx_read(bus->reg_stat) & 0x01;
  51 }
  52
  53 static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
  54 {
  55         struct cx25821_i2c *bus = i2c_adap->algo_data;
  56         struct cx25821_dev *dev = bus->dev;
  57         return cx_read(bus->reg_stat) & 0x02 ? 1 : 0;
  58 }
  59
  60 static int i2c_wait_done(struct i2c_adapter *i2c_adap)
  61 {
  62         int count;
  63
  64         for (count = 0; count < I2C_WAIT_RETRY; count++) {
  65                 if (!i2c_is_busy(i2c_adap))
  66                         break;
  67                 udelay(I2C_WAIT_DELAY);
  68         }
  69
  70         if (I2C_WAIT_RETRY == count)
  71                 return 0;
  72
  73         return 1;
  74 }
  75
  76 static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
  77                          const struct i2c_msg *msg, int joined_rlen)
  78 {
  79         struct cx25821_i2c *bus = i2c_adap->algo_data;
  80         struct cx25821_dev *dev = bus->dev;
  81         u32 wdata, addr, ctrl;
  82         int retval, cnt;
  83
  84         if (joined_rlen)
  85                 dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __func__,
  86                         msg->len, joined_rlen);
  87         else
  88                 dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);
  89
  90         /* Deal with i2c probe functions with zero payload */
  91         if (msg->len == 0) {
  92                 cx_write(bus->reg_addr, msg->addr << 25);
  93                 cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2));
  94
  95                 if (!i2c_wait_done(i2c_adap))
  96                         return -EIO;
  97
  98                 if (!i2c_slave_did_ack(i2c_adap))
  99                         return -EIO;
 100
 101                 dprintk(1, "%s(): returns 0\n", __func__);
 102                 return 0;
 103         }
 104
 105         /* dev, reg + first byte */
 106         addr = (msg->addr << 25) | msg->buf[0];
 107         wdata = msg->buf[0];
 108
 109         ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
 110
 111         if (msg->len > 1)
 112                 ctrl |= I2C_NOSTOP | I2C_EXTEND;
 113         else if (joined_rlen)
 114                 ctrl |= I2C_NOSTOP;
 115
 116         cx_write(bus->reg_addr, addr);
 117         cx_write(bus->reg_wdata, wdata);
 118         cx_write(bus->reg_ctrl, ctrl);
 119
 120         retval = i2c_wait_done(i2c_adap);
 121         if (retval < 0)
 122                 goto err;
 123
 124         if (retval == 0)
 125                 goto eio;
 126
 127         if (i2c_debug) {
 128                 if (!(ctrl & I2C_NOSTOP))
 129                         printk(" >\n");
 130         }
 131
 132         for (cnt = 1; cnt < msg->len; cnt++) {
 133                 /* following bytes */
 134                 wdata = msg->buf[cnt];
 135                 ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
 136
 137                 if (cnt < msg->len - 1)
 138                         ctrl |= I2C_NOSTOP | I2C_EXTEND;
 139                 else if (joined_rlen)
 140                         ctrl |= I2C_NOSTOP;
 141
 142                 cx_write(bus->reg_addr, addr);
 143                 cx_write(bus->reg_wdata, wdata);
 144                 cx_write(bus->reg_ctrl, ctrl);
 145
 146                 retval = i2c_wait_done(i2c_adap);
 147                 if (retval < 0)
 148                         goto err;
 149
 150                 if (retval == 0)
 151                         goto eio;
 152
 153                 if (i2c_debug) {
 154                         dprintk(1, " %02x", msg->buf[cnt]);
 155                         if (!(ctrl & I2C_NOSTOP))
 156                                 dprintk(1, " >\n");
 157                 }
 158         }
 159
 160         return msg->len;
 161
 162 eio:
 163         retval = -EIO;
 164 err:
 165         if (i2c_debug)
 166                 pr_err(" ERR: %d\n", retval);
 167         return retval;
 168 }
 169
 170 static int i2c_readbytes(struct i2c_adapter *i2c_adap,
 171                          const struct i2c_msg *msg, int joined)
 172 {
 173         struct cx25821_i2c *bus = i2c_adap->algo_data;
 174         struct cx25821_dev *dev = bus->dev;
 175         u32 ctrl, cnt;
 176         int retval;
 177
 178         if (i2c_debug && !joined)
 179                 dprintk(1, "6-%s(msg->len=%d)\n", __func__, msg->len);
 180
 181         /* Deal with i2c probe functions with zero payload */
 182         if (msg->len == 0) {
 183                 cx_write(bus->reg_addr, msg->addr << 25);
 184                 cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2) | 1);
 185                 if (!i2c_wait_done(i2c_adap))
 186                         return -EIO;
 187                 if (!i2c_slave_did_ack(i2c_adap))
 188                         return -EIO;
 189
 190                 dprintk(1, "%s(): returns 0\n", __func__);
 191                 return 0;
 192         }
 193
 194         if (i2c_debug) {
 195                 if (joined)
 196                         dprintk(1, " R");
 197                 else
 198                         dprintk(1, " <R %02x", (msg->addr << 1) + 1);
 199         }
 200
 201         for (cnt = 0; cnt < msg->len; cnt++) {
 202
 203                 ctrl = bus->i2c_period | (1 << 12) | (1 << 2) | 1;
 204
 205                 if (cnt < msg->len - 1)
 206                         ctrl |= I2C_NOSTOP | I2C_EXTEND;
 207
 208                 cx_write(bus->reg_addr, msg->addr << 25);
 209                 cx_write(bus->reg_ctrl, ctrl);
 210
 211                 retval = i2c_wait_done(i2c_adap);
 212                 if (retval < 0)
 213                         goto err;
 214                 if (retval == 0)
 215                         goto eio;
 216                 msg->buf[cnt] = cx_read(bus->reg_rdata) & 0xff;
 217
 218                 if (i2c_debug) {
 219                         dprintk(1, " %02x", msg->buf[cnt]);
 220                         if (!(ctrl & I2C_NOSTOP))
 221                                 dprintk(1, " >\n");
 222                 }
 223         }
 224
 225         return msg->len;
 226 eio:
 227         retval = -EIO;
 228 err:
 229         if (i2c_debug)
 230                 pr_err(" ERR: %d\n", retval);
 231         return retval;
 232 }
 233
 234 static int i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
 235 {
 236         struct cx25821_i2c *bus = i2c_adap->algo_data;
 237         struct cx25821_dev *dev = bus->dev;
 238         int i, retval = 0;
 239
 240         dprintk(1, "%s(num = %d)\n", __func__, num);
 241
 242         for (i = 0; i < num; i++) {
 243                 dprintk(1, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
 244                         __func__, num, msgs[i].addr, msgs[i].len);
 245
 246                 if (msgs[i].flags & I2C_M_RD) {
 247                         /* read */
 248                         retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
 249                 } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
 250                            msgs[i].addr == msgs[i + 1].addr) {
 251                         /* write then read from same address */
 252                         retval = i2c_sendbytes(i2c_adap, &msgs[i],
 253                                         msgs[i + 1].len);
 254
 255                         if (retval < 0)
 256                                 goto err;
 257                         i++;
 258                         retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
 259                 } else {
 260                         /* write */
 261                         retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
 262                 }
 263
 264                 if (retval < 0)
 265                         goto err;
 266         }
 267         return num;
 268
 269 err:
 270         return retval;
 271 }
 272
 273
 274 static u32 cx25821_functionality(struct i2c_adapter *adap)
 275 {
 276         return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C | I2C_FUNC_SMBUS_WORD_DATA |
 277                 I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_WRITE_WORD_DATA;
 278 }
 279
 280 static const struct i2c_algorithm cx25821_i2c_algo_template = {
 281         .master_xfer = i2c_xfer,
 282         .functionality = cx25821_functionality,
 283 #ifdef NEED_ALGO_CONTROL
 284         .algo_control = dummy_algo_control,
 285 #endif
 286 };
 287
 288 static const struct i2c_adapter cx25821_i2c_adap_template = {
 289         .name = "cx25821",
 290         .owner = THIS_MODULE,
 291         .algo = &cx25821_i2c_algo_template,
 292 };
 293
 294 static struct i2c_client cx25821_i2c_client_template = {
 295         .name = "cx25821 internal",
 296 };
 297
 298 /* init + register i2c adapter */
 299 int cx25821_i2c_register(struct cx25821_i2c *bus)
 300 {
 301         struct cx25821_dev *dev = bus->dev;
 302
 303         dprintk(1, "%s(bus = %d)\n", __func__, bus->nr);
 304
 305         bus->i2c_adap = cx25821_i2c_adap_template;
 306         bus->i2c_client = cx25821_i2c_client_template;
 307         bus->i2c_adap.dev.parent = &dev->pci->dev;
 308
 309         strlcpy(bus->i2c_adap.name, bus->dev->name, sizeof(bus->i2c_adap.name));
 310
 311         bus->i2c_adap.algo_data = bus;
 312         i2c_set_adapdata(&bus->i2c_adap, &dev->v4l2_dev);
 313         i2c_add_adapter(&bus->i2c_adap);
 314
 315         bus->i2c_client.adapter = &bus->i2c_adap;
 316
 317         /* set up the I2c */
 318         bus->i2c_client.addr = (0x88 >> 1);
 319
 320         return bus->i2c_rc;
 321 }
 322
 323 int cx25821_i2c_unregister(struct cx25821_i2c *bus)
 324 {
 325         i2c_del_adapter(&bus->i2c_adap);
 326         return 0;
 327 }
 328
 329 #if 0 /* Currently unused */
 330 static void cx25821_av_clk(struct cx25821_dev *dev, int enable)
 331 {
 332         /* write 0 to bus 2 addr 0x144 via i2x_xfer() */
 333         char buffer[3];
 334         struct i2c_msg msg;
 335         dprintk(1, "%s(enabled = %d)\n", __func__, enable);
 336
 337         /* Register 0x144 */
 338         buffer[0] = 0x01;
 339         buffer[1] = 0x44;
 340         if (enable == 1)
 341                 buffer[2] = 0x05;
 342         else
 343                 buffer[2] = 0x00;
 344
 345         msg.addr = 0x44;
 346         msg.flags = I2C_M_TEN;
 347         msg.len = 3;
 348         msg.buf = buffer;
 349
 350         i2c_xfer(&dev->i2c_bus[0].i2c_adap, &msg, 1);
 351 }
 352 #endif
 353
 354 int cx25821_i2c_read(struct cx25821_i2c *bus, u16 reg_addr, int *value)
 355 {
 356         struct i2c_client *client = &bus->i2c_client;
 357         int v = 0;
 358         u8 addr[2] = { 0, 0 };
 359         u8 buf[4] = { 0, 0, 0, 0 };
 360
 361         struct i2c_msg msgs[2] = {
 362                 {
 363                         .addr = client->addr,
 364                         .flags = 0,
 365                         .len = 2,
 366                         .buf = addr,
 367                 }, {
 368                         .addr = client->addr,
 369                         .flags = I2C_M_RD,
 370                         .len = 4,
 371                         .buf = buf,
 372                 }
 373         };
 374
 375         addr[0] = (reg_addr >> 8);
 376         addr[1] = (reg_addr & 0xff);
 377         msgs[0].addr = 0x44;
 378         msgs[1].addr = 0x44;
 379
 380         i2c_xfer(client->adapter, msgs, 2);
 381
 382         v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 383         *value = v;
 384
 385         return v;
 386 }
 387
 388 int cx25821_i2c_write(struct cx25821_i2c *bus, u16 reg_addr, int value)
 389 {
 390         struct i2c_client *client = &bus->i2c_client;
 391         int retval = 0;
 392         u8 buf[6] = { 0, 0, 0, 0, 0, 0 };
 393
 394         struct i2c_msg msgs[1] = {
 395                 {
 396                         .addr = client->addr,
 397                         .flags = 0,
 398                         .len = 6,
 399                         .buf = buf,
 400                 }
 401         };
 402
 403         buf[0] = reg_addr >> 8;
 404         buf[1] = reg_addr & 0xff;
 405         buf[5] = (value >> 24) & 0xff;
 406         buf[4] = (value >> 16) & 0xff;
 407         buf[3] = (value >> 8) & 0xff;
 408         buf[2] = value & 0xff;
 409         client->flags = 0;
 410         msgs[0].addr = 0x44;
 411
 412         retval = i2c_xfer(client->adapter, msgs, 1);
 413
 414         return retval;
 415 }