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

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Driver for the Conexant CX25821 PCIe bridge
   4  *
   5  *  Copyright (C) 2009 Conexant Systems Inc.
   6  *  Authors  <shu.lin@conexant.com>, <hiep.huynh@conexant.com>
   7  *      Based on Steven Toth <stoth@linuxtv.org> cx23885 driver
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/module.h>
  13 #include <linux/i2c.h>
  14 #include "cx25821.h"
  15
  16 static unsigned int i2c_debug;
  17 module_param(i2c_debug, int, 0644);
  18 MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
  19
  20 static unsigned int i2c_scan;
  21 module_param(i2c_scan, int, 0444);
  22 MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
  23
  24 #define dprintk(level, fmt, arg...)                                     \
  25 do {                                                                    \
  26         if (i2c_debug >= level)                                         \
  27                 printk(KERN_DEBUG "%s/0: " fmt, dev->name, ##arg);      \
  28 } while (0)
  29
  30 #define I2C_WAIT_DELAY 32
  31 #define I2C_WAIT_RETRY 64
  32
  33 #define I2C_EXTEND  (1 << 3)
  34 #define I2C_NOSTOP  (1 << 4)
  35
  36 static inline int i2c_slave_did_ack(struct i2c_adapter *i2c_adap)
  37 {
  38         struct cx25821_i2c *bus = i2c_adap->algo_data;
  39         struct cx25821_dev *dev = bus->dev;
  40         return cx_read(bus->reg_stat) & 0x01;
  41 }
  42
  43 static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
  44 {
  45         struct cx25821_i2c *bus = i2c_adap->algo_data;
  46         struct cx25821_dev *dev = bus->dev;
  47         return cx_read(bus->reg_stat) & 0x02 ? 1 : 0;
  48 }
  49
  50 static int i2c_wait_done(struct i2c_adapter *i2c_adap)
  51 {
  52         int count;
  53
  54         for (count = 0; count < I2C_WAIT_RETRY; count++) {
  55                 if (!i2c_is_busy(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 int i2c_sendbytes(struct i2c_adapter *i2c_adap,
  67                          const struct i2c_msg *msg, int joined_rlen)
  68 {
  69         struct cx25821_i2c *bus = i2c_adap->algo_data;
  70         struct cx25821_dev *dev = bus->dev;
  71         u32 wdata, addr, ctrl;
  72         int retval, cnt;
  73
  74         if (joined_rlen)
  75                 dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __func__,
  76                         msg->len, joined_rlen);
  77         else
  78                 dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);
  79
  80         /* Deal with i2c probe functions with zero payload */
  81         if (msg->len == 0) {
  82                 cx_write(bus->reg_addr, msg->addr << 25);
  83                 cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2));
  84
  85                 if (!i2c_wait_done(i2c_adap))
  86                         return -EIO;
  87
  88                 if (!i2c_slave_did_ack(i2c_adap))
  89                         return -EIO;
  90
  91                 dprintk(1, "%s(): returns 0\n", __func__);
  92                 return 0;
  93         }
  94
  95         /* dev, reg + first byte */
  96         addr = (msg->addr << 25) | msg->buf[0];
  97         wdata = msg->buf[0];
  98
  99         ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
 100
 101         if (msg->len > 1)
 102                 ctrl |= I2C_NOSTOP | I2C_EXTEND;
 103         else if (joined_rlen)
 104                 ctrl |= I2C_NOSTOP;
 105
 106         cx_write(bus->reg_addr, addr);
 107         cx_write(bus->reg_wdata, wdata);
 108         cx_write(bus->reg_ctrl, ctrl);
 109
 110         retval = i2c_wait_done(i2c_adap);
 111         if (retval < 0)
 112                 goto err;
 113
 114         if (retval == 0)
 115                 goto eio;
 116
 117         if (i2c_debug) {
 118                 if (!(ctrl & I2C_NOSTOP))
 119                         printk(" >\n");
 120         }
 121
 122         for (cnt = 1; cnt < msg->len; cnt++) {
 123                 /* following bytes */
 124                 wdata = msg->buf[cnt];
 125                 ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
 126
 127                 if (cnt < msg->len - 1)
 128                         ctrl |= I2C_NOSTOP | I2C_EXTEND;
 129                 else if (joined_rlen)
 130                         ctrl |= I2C_NOSTOP;
 131
 132                 cx_write(bus->reg_addr, addr);
 133                 cx_write(bus->reg_wdata, wdata);
 134                 cx_write(bus->reg_ctrl, ctrl);
 135
 136                 retval = i2c_wait_done(i2c_adap);
 137                 if (retval < 0)
 138                         goto err;
 139
 140                 if (retval == 0)
 141                         goto eio;
 142
 143                 if (i2c_debug) {
 144                         dprintk(1, " %02x", msg->buf[cnt]);
 145                         if (!(ctrl & I2C_NOSTOP))
 146                                 dprintk(1, " >\n");
 147                 }
 148         }
 149
 150         return msg->len;
 151
 152 eio:
 153         retval = -EIO;
 154 err:
 155         if (i2c_debug)
 156                 pr_err(" ERR: %d\n", retval);
 157         return retval;
 158 }
 159
 160 static int i2c_readbytes(struct i2c_adapter *i2c_adap,
 161                          const struct i2c_msg *msg, int joined)
 162 {
 163         struct cx25821_i2c *bus = i2c_adap->algo_data;
 164         struct cx25821_dev *dev = bus->dev;
 165         u32 ctrl, cnt;
 166         int retval;
 167
 168         if (i2c_debug && !joined)
 169                 dprintk(1, "6-%s(msg->len=%d)\n", __func__, msg->len);
 170
 171         /* Deal with i2c probe functions with zero payload */
 172         if (msg->len == 0) {
 173                 cx_write(bus->reg_addr, msg->addr << 25);
 174                 cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2) | 1);
 175                 if (!i2c_wait_done(i2c_adap))
 176                         return -EIO;
 177                 if (!i2c_slave_did_ack(i2c_adap))
 178                         return -EIO;
 179
 180                 dprintk(1, "%s(): returns 0\n", __func__);
 181                 return 0;
 182         }
 183
 184         if (i2c_debug) {
 185                 if (joined)
 186                         dprintk(1, " R");
 187                 else
 188                         dprintk(1, " <R %02x", (msg->addr << 1) + 1);
 189         }
 190
 191         for (cnt = 0; cnt < msg->len; cnt++) {
 192
 193                 ctrl = bus->i2c_period | (1 << 12) | (1 << 2) | 1;
 194
 195                 if (cnt < msg->len - 1)
 196                         ctrl |= I2C_NOSTOP | I2C_EXTEND;
 197
 198                 cx_write(bus->reg_addr, msg->addr << 25);
 199                 cx_write(bus->reg_ctrl, ctrl);
 200
 201                 retval = i2c_wait_done(i2c_adap);
 202                 if (retval < 0)
 203                         goto err;
 204                 if (retval == 0)
 205                         goto eio;
 206                 msg->buf[cnt] = cx_read(bus->reg_rdata) & 0xff;
 207
 208                 if (i2c_debug) {
 209                         dprintk(1, " %02x", msg->buf[cnt]);
 210                         if (!(ctrl & I2C_NOSTOP))
 211                                 dprintk(1, " >\n");
 212                 }
 213         }
 214
 215         return msg->len;
 216 eio:
 217         retval = -EIO;
 218 err:
 219         if (i2c_debug)
 220                 pr_err(" ERR: %d\n", retval);
 221         return retval;
 222 }
 223
 224 static int i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
 225 {
 226         struct cx25821_i2c *bus = i2c_adap->algo_data;
 227         struct cx25821_dev *dev = bus->dev;
 228         int i, retval = 0;
 229
 230         dprintk(1, "%s(num = %d)\n", __func__, num);
 231
 232         for (i = 0; i < num; i++) {
 233                 dprintk(1, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
 234                         __func__, num, msgs[i].addr, msgs[i].len);
 235
 236                 if (msgs[i].flags & I2C_M_RD) {
 237                         /* read */
 238                         retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
 239                 } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
 240                            msgs[i].addr == msgs[i + 1].addr) {
 241                         /* write then read from same address */
 242                         retval = i2c_sendbytes(i2c_adap, &msgs[i],
 243                                         msgs[i + 1].len);
 244
 245                         if (retval < 0)
 246                                 goto err;
 247                         i++;
 248                         retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
 249                 } else {
 250                         /* write */
 251                         retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
 252                 }
 253
 254                 if (retval < 0)
 255                         goto err;
 256         }
 257         return num;
 258
 259 err:
 260         return retval;
 261 }
 262
 263
 264 static u32 cx25821_functionality(struct i2c_adapter *adap)
 265 {
 266         return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C | I2C_FUNC_SMBUS_WORD_DATA |
 267                 I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_WRITE_WORD_DATA;
 268 }
 269
 270 static const struct i2c_algorithm cx25821_i2c_algo_template = {
 271         .master_xfer = i2c_xfer,
 272         .functionality = cx25821_functionality,
 273 #ifdef NEED_ALGO_CONTROL
 274         .algo_control = dummy_algo_control,
 275 #endif
 276 };
 277
 278 static const struct i2c_adapter cx25821_i2c_adap_template = {
 279         .name = "cx25821",
 280         .owner = THIS_MODULE,
 281         .algo = &cx25821_i2c_algo_template,
 282 };
 283
 284 static const struct i2c_client cx25821_i2c_client_template = {
 285         .name = "cx25821 internal",
 286 };
 287
 288 /* init + register i2c adapter */
 289 int cx25821_i2c_register(struct cx25821_i2c *bus)
 290 {
 291         struct cx25821_dev *dev = bus->dev;
 292
 293         dprintk(1, "%s(bus = %d)\n", __func__, bus->nr);
 294
 295         bus->i2c_adap = cx25821_i2c_adap_template;
 296         bus->i2c_client = cx25821_i2c_client_template;
 297         bus->i2c_adap.dev.parent = &dev->pci->dev;
 298
 299         strscpy(bus->i2c_adap.name, bus->dev->name, sizeof(bus->i2c_adap.name));
 300
 301         bus->i2c_adap.algo_data = bus;
 302         i2c_set_adapdata(&bus->i2c_adap, &dev->v4l2_dev);
 303         i2c_add_adapter(&bus->i2c_adap);
 304
 305         bus->i2c_client.adapter = &bus->i2c_adap;
 306
 307         /* set up the I2c */
 308         bus->i2c_client.addr = (0x88 >> 1);
 309
 310         return bus->i2c_rc;
 311 }
 312
 313 int cx25821_i2c_unregister(struct cx25821_i2c *bus)
 314 {
 315         i2c_del_adapter(&bus->i2c_adap);
 316         return 0;
 317 }
 318
 319 #if 0 /* Currently unused */
 320 static void cx25821_av_clk(struct cx25821_dev *dev, int enable)
 321 {
 322         /* write 0 to bus 2 addr 0x144 via i2x_xfer() */
 323         char buffer[3];
 324         struct i2c_msg msg;
 325         dprintk(1, "%s(enabled = %d)\n", __func__, enable);
 326
 327         /* Register 0x144 */
 328         buffer[0] = 0x01;
 329         buffer[1] = 0x44;
 330         if (enable == 1)
 331                 buffer[2] = 0x05;
 332         else
 333                 buffer[2] = 0x00;
 334
 335         msg.addr = 0x44;
 336         msg.flags = I2C_M_TEN;
 337         msg.len = 3;
 338         msg.buf = buffer;
 339
 340         i2c_xfer(&dev->i2c_bus[0].i2c_adap, &msg, 1);
 341 }
 342 #endif
 343
 344 int cx25821_i2c_read(struct cx25821_i2c *bus, u16 reg_addr, int *value)
 345 {
 346         struct i2c_client *client = &bus->i2c_client;
 347         int v = 0;
 348         u8 addr[2] = { 0, 0 };
 349         u8 buf[4] = { 0, 0, 0, 0 };
 350
 351         struct i2c_msg msgs[2] = {
 352                 {
 353                         .addr = client->addr,
 354                         .flags = 0,
 355                         .len = 2,
 356                         .buf = addr,
 357                 }, {
 358                         .addr = client->addr,
 359                         .flags = I2C_M_RD,
 360                         .len = 4,
 361                         .buf = buf,
 362                 }
 363         };
 364
 365         addr[0] = (reg_addr >> 8);
 366         addr[1] = (reg_addr & 0xff);
 367         msgs[0].addr = 0x44;
 368         msgs[1].addr = 0x44;
 369
 370         i2c_xfer(client->adapter, msgs, 2);
 371
 372         v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 373         *value = v;
 374
 375         return v;
 376 }
 377
 378 int cx25821_i2c_write(struct cx25821_i2c *bus, u16 reg_addr, int value)
 379 {
 380         struct i2c_client *client = &bus->i2c_client;
 381         int retval = 0;
 382         u8 buf[6] = { 0, 0, 0, 0, 0, 0 };
 383
 384         struct i2c_msg msgs[1] = {
 385                 {
 386                         .addr = client->addr,
 387                         .flags = 0,
 388                         .len = 6,
 389                         .buf = buf,
 390                 }
 391         };
 392
 393         buf[0] = reg_addr >> 8;
 394         buf[1] = reg_addr & 0xff;
 395         buf[5] = (value >> 24) & 0xff;
 396         buf[4] = (value >> 16) & 0xff;
 397         buf[3] = (value >> 8) & 0xff;
 398         buf[2] = value & 0xff;
 399         client->flags = 0;
 400         msgs[0].addr = 0x44;
 401
 402         retval = i2c_xfer(client->adapter, msgs, 1);
 403
 404         return retval;
 405 }