LXR linux/drivers/media/video/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 *  You should have received a copy of the GNU General Public License
  18 *  along with this program; if not, write to the Free Software
  19 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22#include <linux/module.h>
  23#include <linux/moduleparam.h>
  24#include <linux/init.h>
  25#include <linux/delay.h>
  26#include <linux/io.h>
  27
  28#include "au0828.h"
  29
  30#include <media/v4l2-common.h>
  31
  32static int i2c_scan;
  33module_param(i2c_scan, int, 0444);
  34MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
  35
  36#define I2C_WAIT_DELAY 512
  37#define I2C_WAIT_RETRY 64
  38
  39static inline int i2c_slave_did_write_ack(struct i2c_adapter *i2c_adap)
  40{
  41        struct au0828_dev *dev = i2c_adap->algo_data;
  42        return au0828_read(dev, AU0828_I2C_STATUS_201) &
  43                AU0828_I2C_STATUS_NO_WRITE_ACK ? 0 : 1;
  44}
  45
  46static inline int i2c_slave_did_read_ack(struct i2c_adapter *i2c_adap)
  47{
  48        struct au0828_dev *dev = i2c_adap->algo_data;
  49        return au0828_read(dev, AU0828_I2C_STATUS_201) &
  50                AU0828_I2C_STATUS_NO_READ_ACK ? 0 : 1;
  51}
  52
  53static int i2c_wait_read_ack(struct i2c_adapter *i2c_adap)
  54{
  55        int count;
  56
  57        for (count = 0; count < I2C_WAIT_RETRY; count++) {
  58                if (!i2c_slave_did_read_ack(i2c_adap))
  59                        break;
  60                udelay(I2C_WAIT_DELAY);
  61        }
  62
  63        if (I2C_WAIT_RETRY == count)
  64                return 0;
  65
  66        return 1;
  67}
  68
  69static inline int i2c_is_read_busy(struct i2c_adapter *i2c_adap)
  70{
  71        struct au0828_dev *dev = i2c_adap->algo_data;
  72        return au0828_read(dev, AU0828_I2C_STATUS_201) &
  73                AU0828_I2C_STATUS_READ_DONE ? 0 : 1;
  74}
  75
  76static int i2c_wait_read_done(struct i2c_adapter *i2c_adap)
  77{
  78        int count;
  79
  80        for (count = 0; count < I2C_WAIT_RETRY; count++) {
  81                if (!i2c_is_read_busy(i2c_adap))
  82                        break;
  83                udelay(I2C_WAIT_DELAY);
  84        }
  85
  86        if (I2C_WAIT_RETRY == count)
  87                return 0;
  88
  89        return 1;
  90}
  91
  92static inline int i2c_is_write_done(struct i2c_adapter *i2c_adap)
  93{
  94        struct au0828_dev *dev = i2c_adap->algo_data;
  95        return au0828_read(dev, AU0828_I2C_STATUS_201) &
  96                AU0828_I2C_STATUS_WRITE_DONE ? 1 : 0;
  97}
  98
  99static int i2c_wait_write_done(struct i2c_adapter *i2c_adap)
 100{
 101        int count;
 102
 103        for (count = 0; count < I2C_WAIT_RETRY; count++) {
 104                if (i2c_is_write_done(i2c_adap))
 105                        break;
 106                udelay(I2C_WAIT_DELAY);
 107        }
 108
 109        if (I2C_WAIT_RETRY == count)
 110                return 0;
 111
 112        return 1;
 113}
 114
 115static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
 116{
 117        struct au0828_dev *dev = i2c_adap->algo_data;
 118        return au0828_read(dev, AU0828_I2C_STATUS_201) &
 119                AU0828_I2C_STATUS_BUSY ? 1 : 0;
 120}
 121
 122static int i2c_wait_done(struct i2c_adapter *i2c_adap)
 123{
 124        int count;
 125
 126        for (count = 0; count < I2C_WAIT_RETRY; count++) {
 127                if (!i2c_is_busy(i2c_adap))
 128                        break;
 129                udelay(I2C_WAIT_DELAY);
 130        }
 131
 132        if (I2C_WAIT_RETRY == count)
 133                return 0;
 134
 135        return 1;
 136}
 137
 138/* FIXME: Implement join handling correctly */
 139static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
 140        const struct i2c_msg *msg, int joined_rlen)
 141{
 142        int i, strobe = 0;
 143        struct au0828_dev *dev = i2c_adap->algo_data;
 144
 145        dprintk(4, "%s()\n", __func__);
 146
 147        au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
 148
 149        /* Set the I2C clock */
 150        au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
 151                     dev->board.i2c_clk_divider);
 152
 153        /* Hardware needs 8 bit addresses */
 154        au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
 155
 156        dprintk(4, "SEND: %02x\n", msg->addr);
 157
 158        /* Deal with i2c_scan */
 159        if (msg->len == 0) {
 160                /* The analog tuner detection code makes use of the SMBUS_QUICK
 161                   message (which involves a zero length i2c write).  To avoid
 162                   checking the status register when we didn't strobe out any
 163                   actual bytes to the bus, just do a read check.  This is
 164                   consistent with how I saw i2c device checking done in the
 165                   USB trace of the Windows driver */
 166                au0828_write(dev, AU0828_I2C_TRIGGER_200,
 167                             AU0828_I2C_TRIGGER_READ);
 168
 169                if (!i2c_wait_done(i2c_adap))
 170                        return -EIO;
 171
 172                if (i2c_wait_read_ack(i2c_adap))
 173                        return -EIO;
 174
 175                return 0;
 176        }
 177
 178        for (i = 0; i < msg->len;) {
 179
 180                dprintk(4, " %02x\n", msg->buf[i]);
 181
 182                au0828_write(dev, AU0828_I2C_WRITE_FIFO_205, msg->buf[i]);
 183
 184                strobe++;
 185                i++;
 186
 187                if ((strobe >= 4) || (i >= msg->len)) {
 188
 189                        /* Strobe the byte into the bus */
 190                        if (i < msg->len)
 191                                au0828_write(dev, AU0828_I2C_TRIGGER_200,
 192                                             AU0828_I2C_TRIGGER_WRITE |
 193                                             AU0828_I2C_TRIGGER_HOLD);
 194                        else
 195                                au0828_write(dev, AU0828_I2C_TRIGGER_200,
 196                                             AU0828_I2C_TRIGGER_WRITE);
 197
 198                        /* Reset strobe trigger */
 199                        strobe = 0;
 200
 201                        if (!i2c_wait_write_done(i2c_adap))
 202                                return -EIO;
 203
 204                }
 205
 206        }
 207        if (!i2c_wait_done(i2c_adap))
 208                return -EIO;
 209
 210        dprintk(4, "\n");
 211
 212        return msg->len;
 213}
 214
 215/* FIXME: Implement join handling correctly */
 216static int i2c_readbytes(struct i2c_adapter *i2c_adap,
 217        const struct i2c_msg *msg, int joined)
 218{
 219        struct au0828_dev *dev = i2c_adap->algo_data;
 220        int i;
 221
 222        dprintk(4, "%s()\n", __func__);
 223
 224        au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
 225
 226        /* Set the I2C clock */
 227        au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
 228                     dev->board.i2c_clk_divider);
 229
 230        /* Hardware needs 8 bit addresses */
 231        au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
 232
 233        dprintk(4, " RECV:\n");
 234
 235        /* Deal with i2c_scan */
 236        if (msg->len == 0) {
 237                au0828_write(dev, AU0828_I2C_TRIGGER_200,
 238                             AU0828_I2C_TRIGGER_READ);
 239
 240                if (i2c_wait_read_ack(i2c_adap))
 241                        return -EIO;
 242                return 0;
 243        }
 244
 245        for (i = 0; i < msg->len;) {
 246
 247                i++;
 248
 249                if (i < msg->len)
 250                        au0828_write(dev, AU0828_I2C_TRIGGER_200,
 251                                     AU0828_I2C_TRIGGER_READ |
 252                                     AU0828_I2C_TRIGGER_HOLD);
 253                else
 254                        au0828_write(dev, AU0828_I2C_TRIGGER_200,
 255                                     AU0828_I2C_TRIGGER_READ);
 256
 257                if (!i2c_wait_read_done(i2c_adap))
 258                        return -EIO;
 259
 260                msg->buf[i-1] = au0828_read(dev, AU0828_I2C_READ_FIFO_209) &
 261                        0xff;
 262
 263                dprintk(4, " %02x\n", msg->buf[i-1]);
 264        }
 265        if (!i2c_wait_done(i2c_adap))
 266                return -EIO;
 267
 268        dprintk(4, "\n");
 269
 270        return msg->len;
 271}
 272
 273static int i2c_xfer(struct i2c_adapter *i2c_adap,
 274                    struct i2c_msg *msgs, int num)
 275{
 276        int i, retval = 0;
 277
 278        dprintk(4, "%s(num = %d)\n", __func__, num);
 279
 280        for (i = 0; i < num; i++) {
 281                dprintk(4, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
 282                        __func__, num, msgs[i].addr, msgs[i].len);
 283                if (msgs[i].flags & I2C_M_RD) {
 284                        /* read */
 285                        retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
 286                } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
 287                           msgs[i].addr == msgs[i + 1].addr) {
 288                        /* write then read from same address */
 289                        retval = i2c_sendbytes(i2c_adap, &msgs[i],
 290                                               msgs[i + 1].len);
 291                        if (retval < 0)
 292                                goto err;
 293                        i++;
 294                        retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
 295                } else {
 296                        /* write */
 297                        retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
 298                }
 299                if (retval < 0)
 300                        goto err;
 301        }
 302        return num;
 303
 304err:
 305        return retval;
 306}
 307
 308static u32 au0828_functionality(struct i2c_adapter *adap)
 309{
 310        return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
 311}
 312
 313static struct i2c_algorithm au0828_i2c_algo_template = {
 314        .master_xfer    = i2c_xfer,
 315        .functionality  = au0828_functionality,
 316};
 317
 318/* ----------------------------------------------------------------------- */
 319
 320static struct i2c_adapter au0828_i2c_adap_template = {
 321        .name              = DRIVER_NAME,
 322        .owner             = THIS_MODULE,
 323        .algo              = &au0828_i2c_algo_template,
 324};
 325
 326static struct i2c_client au0828_i2c_client_template = {
 327        .name   = "au0828 internal",
 328};
 329
 330static char *i2c_devs[128] = {
 331        [0x8e >> 1] = "au8522",
 332        [0xa0 >> 1] = "eeprom",
 333        [0xc2 >> 1] = "tuner/xc5000",
 334};
 335
 336static void do_i2c_scan(char *name, struct i2c_client *c)
 337{
 338        unsigned char buf;
 339        int i, rc;
 340
 341        for (i = 0; i < 128; i++) {
 342                c->addr = i;
 343                rc = i2c_master_recv(c, &buf, 0);
 344                if (rc < 0)
 345                        continue;
 346                printk(KERN_INFO "%s: i2c scan: found device @ 0x%x  [%s]\n",
 347                       name, i << 1, i2c_devs[i] ? i2c_devs[i] : "???");
 348        }
 349}
 350
 351/* init + register i2c algo-bit adapter */
 352int au0828_i2c_register(struct au0828_dev *dev)
 353{
 354        dprintk(1, "%s()\n", __func__);
 355
 356        memcpy(&dev->i2c_adap, &au0828_i2c_adap_template,
 357               sizeof(dev->i2c_adap));
 358        memcpy(&dev->i2c_algo, &au0828_i2c_algo_template,
 359               sizeof(dev->i2c_algo));
 360        memcpy(&dev->i2c_client, &au0828_i2c_client_template,
 361               sizeof(dev->i2c_client));
 362
 363        dev->i2c_adap.dev.parent = &dev->usbdev->dev;
 364
 365        strlcpy(dev->i2c_adap.name, DRIVER_NAME,
 366                sizeof(dev->i2c_adap.name));
 367
 368        dev->i2c_adap.algo = &dev->i2c_algo;
 369        dev->i2c_adap.algo_data = dev;
 370        i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
 371        i2c_add_adapter(&dev->i2c_adap);
 372
 373        dev->i2c_client.adapter = &dev->i2c_adap;
 374
 375        if (0 == dev->i2c_rc) {
 376                printk(KERN_INFO "%s: i2c bus registered\n", DRIVER_NAME);
 377                if (i2c_scan)
 378                        do_i2c_scan(DRIVER_NAME, &dev->i2c_client);
 379        } else
 380                printk(KERN_INFO "%s: i2c bus register FAILED\n", DRIVER_NAME);
 381
 382        return dev->i2c_rc;
 383}
 384
 385int au0828_i2c_unregister(struct au0828_dev *dev)
 386{
 387        i2c_del_adapter(&dev->i2c_adap);
 388        return 0;
 389}
 390
 391