drivers/i2c/busses/i2c-uniphier-f.c

   1 /*
   2  * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/clk.h>
  16 #include <linux/i2c.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/io.h>
  19 #include <linux/module.h>
  20 #include <linux/platform_device.h>
  21
  22 #define UNIPHIER_FI2C_CR        0x00    /* control register */
  23 #define     UNIPHIER_FI2C_CR_MST        BIT(3)  /* master mode */
  24 #define     UNIPHIER_FI2C_CR_STA        BIT(2)  /* start condition */
  25 #define     UNIPHIER_FI2C_CR_STO        BIT(1)  /* stop condition */
  26 #define     UNIPHIER_FI2C_CR_NACK       BIT(0)  /* do not return ACK */
  27 #define UNIPHIER_FI2C_DTTX      0x04    /* TX FIFO */
  28 #define     UNIPHIER_FI2C_DTTX_CMD      BIT(8)  /* send command (slave addr) */
  29 #define     UNIPHIER_FI2C_DTTX_RD       BIT(0)  /* read transaction */
  30 #define UNIPHIER_FI2C_DTRX      0x04    /* RX FIFO */
  31 #define UNIPHIER_FI2C_SLAD      0x0c    /* slave address */
  32 #define UNIPHIER_FI2C_CYC       0x10    /* clock cycle control */
  33 #define UNIPHIER_FI2C_LCTL      0x14    /* clock low period control */
  34 #define UNIPHIER_FI2C_SSUT      0x18    /* restart/stop setup time control */
  35 #define UNIPHIER_FI2C_DSUT      0x1c    /* data setup time control */
  36 #define UNIPHIER_FI2C_INT       0x20    /* interrupt status */
  37 #define UNIPHIER_FI2C_IE        0x24    /* interrupt enable */
  38 #define UNIPHIER_FI2C_IC        0x28    /* interrupt clear */
  39 #define     UNIPHIER_FI2C_INT_TE        BIT(9)  /* TX FIFO empty */
  40 #define     UNIPHIER_FI2C_INT_RF        BIT(8)  /* RX FIFO full */
  41 #define     UNIPHIER_FI2C_INT_TC        BIT(7)  /* send complete (STOP) */
  42 #define     UNIPHIER_FI2C_INT_RC        BIT(6)  /* receive complete (STOP) */
  43 #define     UNIPHIER_FI2C_INT_TB        BIT(5)  /* sent specified bytes */
  44 #define     UNIPHIER_FI2C_INT_RB        BIT(4)  /* received specified bytes */
  45 #define     UNIPHIER_FI2C_INT_NA        BIT(2)  /* no ACK */
  46 #define     UNIPHIER_FI2C_INT_AL        BIT(1)  /* arbitration lost */
  47 #define UNIPHIER_FI2C_SR        0x2c    /* status register */
  48 #define     UNIPHIER_FI2C_SR_DB         BIT(12) /* device busy */
  49 #define     UNIPHIER_FI2C_SR_STS        BIT(11) /* stop condition detected */
  50 #define     UNIPHIER_FI2C_SR_BB         BIT(8)  /* bus busy */
  51 #define     UNIPHIER_FI2C_SR_RFF        BIT(3)  /* RX FIFO full */
  52 #define     UNIPHIER_FI2C_SR_RNE        BIT(2)  /* RX FIFO not empty */
  53 #define     UNIPHIER_FI2C_SR_TNF        BIT(1)  /* TX FIFO not full */
  54 #define     UNIPHIER_FI2C_SR_TFE        BIT(0)  /* TX FIFO empty */
  55 #define UNIPHIER_FI2C_RST       0x34    /* reset control */
  56 #define     UNIPHIER_FI2C_RST_TBRST     BIT(2)  /* clear TX FIFO */
  57 #define     UNIPHIER_FI2C_RST_RBRST     BIT(1)  /* clear RX FIFO */
  58 #define     UNIPHIER_FI2C_RST_RST       BIT(0)  /* forcible bus reset */
  59 #define UNIPHIER_FI2C_BM        0x38    /* bus monitor */
  60 #define     UNIPHIER_FI2C_BM_SDAO       BIT(3)  /* output for SDA line */
  61 #define     UNIPHIER_FI2C_BM_SDAS       BIT(2)  /* readback of SDA line */
  62 #define     UNIPHIER_FI2C_BM_SCLO       BIT(1)  /* output for SCL line */
  63 #define     UNIPHIER_FI2C_BM_SCLS       BIT(0)  /* readback of SCL line */
  64 #define UNIPHIER_FI2C_NOISE     0x3c    /* noise filter control */
  65 #define UNIPHIER_FI2C_TBC       0x40    /* TX byte count setting */
  66 #define UNIPHIER_FI2C_RBC       0x44    /* RX byte count setting */
  67 #define UNIPHIER_FI2C_TBCM      0x48    /* TX byte count monitor */
  68 #define UNIPHIER_FI2C_RBCM      0x4c    /* RX byte count monitor */
  69 #define UNIPHIER_FI2C_BRST      0x50    /* bus reset */
  70 #define     UNIPHIER_FI2C_BRST_FOEN     BIT(1)  /* normal operation */
  71 #define     UNIPHIER_FI2C_BRST_RSCL     BIT(0)  /* release SCL */
  72
  73 #define UNIPHIER_FI2C_INT_FAULTS        \
  74                                 (UNIPHIER_FI2C_INT_NA | UNIPHIER_FI2C_INT_AL)
  75 #define UNIPHIER_FI2C_INT_STOP          \
  76                                 (UNIPHIER_FI2C_INT_TC | UNIPHIER_FI2C_INT_RC)
  77
  78 #define UNIPHIER_FI2C_RD                BIT(0)
  79 #define UNIPHIER_FI2C_STOP              BIT(1)
  80 #define UNIPHIER_FI2C_MANUAL_NACK       BIT(2)
  81 #define UNIPHIER_FI2C_BYTE_WISE         BIT(3)
  82 #define UNIPHIER_FI2C_DEFER_STOP_COMP   BIT(4)
  83
  84 #define UNIPHIER_FI2C_DEFAULT_SPEED     100000
  85 #define UNIPHIER_FI2C_MAX_SPEED         400000
  86 #define UNIPHIER_FI2C_FIFO_SIZE         8
  87
  88 struct uniphier_fi2c_priv {
  89         struct completion comp;
  90         struct i2c_adapter adap;
  91         void __iomem *membase;
  92         struct clk *clk;
  93         unsigned int len;
  94         u8 *buf;
  95         u32 enabled_irqs;
  96         int error;
  97         unsigned int flags;
  98         unsigned int busy_cnt;
  99 };
 100
 101 static void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv,
 102                                       bool first)
 103 {
 104         int fifo_space = UNIPHIER_FI2C_FIFO_SIZE;
 105
 106         /*
 107          * TX-FIFO stores slave address in it for the first access.
 108          * Decrement the counter.
 109          */
 110         if (first)
 111                 fifo_space--;
 112
 113         while (priv->len) {
 114                 if (fifo_space-- <= 0)
 115                         break;
 116
 117                 dev_dbg(&priv->adap.dev, "write data: %02x\n", *priv->buf);
 118                 writel(*priv->buf++, priv->membase + UNIPHIER_FI2C_DTTX);
 119                 priv->len--;
 120         }
 121 }
 122
 123 static void uniphier_fi2c_drain_rxfifo(struct uniphier_fi2c_priv *priv)
 124 {
 125         int fifo_left = priv->flags & UNIPHIER_FI2C_BYTE_WISE ?
 126                                                 1 : UNIPHIER_FI2C_FIFO_SIZE;
 127
 128         while (priv->len) {
 129                 if (fifo_left-- <= 0)
 130                         break;
 131
 132                 *priv->buf++ = readl(priv->membase + UNIPHIER_FI2C_DTRX);
 133                 dev_dbg(&priv->adap.dev, "read data: %02x\n", priv->buf[-1]);
 134                 priv->len--;
 135         }
 136 }
 137
 138 static void uniphier_fi2c_set_irqs(struct uniphier_fi2c_priv *priv)
 139 {
 140         writel(priv->enabled_irqs, priv->membase + UNIPHIER_FI2C_IE);
 141 }
 142
 143 static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv)
 144 {
 145         writel(-1, priv->membase + UNIPHIER_FI2C_IC);
 146 }
 147
 148 static void uniphier_fi2c_stop(struct uniphier_fi2c_priv *priv)
 149 {
 150         dev_dbg(&priv->adap.dev, "stop condition\n");
 151
 152         priv->enabled_irqs |= UNIPHIER_FI2C_INT_STOP;
 153         uniphier_fi2c_set_irqs(priv);
 154         writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STO,
 155                priv->membase + UNIPHIER_FI2C_CR);
 156 }
 157
 158 static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
 159 {
 160         struct uniphier_fi2c_priv *priv = dev_id;
 161         u32 irq_status;
 162
 163         irq_status = readl(priv->membase + UNIPHIER_FI2C_INT);
 164
 165         dev_dbg(&priv->adap.dev,
 166                 "interrupt: enabled_irqs=%04x, irq_status=%04x\n",
 167                 priv->enabled_irqs, irq_status);
 168
 169         if (irq_status & UNIPHIER_FI2C_INT_STOP)
 170                 goto complete;
 171
 172         if (unlikely(irq_status & UNIPHIER_FI2C_INT_AL)) {
 173                 dev_dbg(&priv->adap.dev, "arbitration lost\n");
 174                 priv->error = -EAGAIN;
 175                 goto complete;
 176         }
 177
 178         if (unlikely(irq_status & UNIPHIER_FI2C_INT_NA)) {
 179                 dev_dbg(&priv->adap.dev, "could not get ACK\n");
 180                 priv->error = -ENXIO;
 181                 if (priv->flags & UNIPHIER_FI2C_RD) {
 182                         /*
 183                          * work around a hardware bug:
 184                          * The receive-completed interrupt is never set even if
 185                          * STOP condition is detected after the address phase
 186                          * of read transaction fails to get ACK.
 187                          * To avoid time-out error, we issue STOP here,
 188                          * but do not wait for its completion.
 189                          * It should be checked after exiting this handler.
 190                          */
 191                         uniphier_fi2c_stop(priv);
 192                         priv->flags |= UNIPHIER_FI2C_DEFER_STOP_COMP;
 193                         goto complete;
 194                 }
 195                 goto stop;
 196         }
 197
 198         if (irq_status & UNIPHIER_FI2C_INT_TE) {
 199                 if (!priv->len)
 200                         goto data_done;
 201
 202                 uniphier_fi2c_fill_txfifo(priv, false);
 203                 goto handled;
 204         }
 205
 206         if (irq_status & (UNIPHIER_FI2C_INT_RF | UNIPHIER_FI2C_INT_RB)) {
 207                 uniphier_fi2c_drain_rxfifo(priv);
 208                 if (!priv->len)
 209                         goto data_done;
 210
 211                 if (unlikely(priv->flags & UNIPHIER_FI2C_MANUAL_NACK)) {
 212                         if (priv->len <= UNIPHIER_FI2C_FIFO_SIZE &&
 213                             !(priv->flags & UNIPHIER_FI2C_BYTE_WISE)) {
 214                                 dev_dbg(&priv->adap.dev,
 215                                         "enable read byte count IRQ\n");
 216                                 priv->enabled_irqs |= UNIPHIER_FI2C_INT_RB;
 217                                 uniphier_fi2c_set_irqs(priv);
 218                                 priv->flags |= UNIPHIER_FI2C_BYTE_WISE;
 219                         }
 220                         if (priv->len <= 1) {
 221                                 dev_dbg(&priv->adap.dev, "set NACK\n");
 222                                 writel(UNIPHIER_FI2C_CR_MST |
 223                                        UNIPHIER_FI2C_CR_NACK,
 224                                        priv->membase + UNIPHIER_FI2C_CR);
 225                         }
 226                 }
 227
 228                 goto handled;
 229         }
 230
 231         return IRQ_NONE;
 232
 233 data_done:
 234         if (priv->flags & UNIPHIER_FI2C_STOP) {
 235 stop:
 236                 uniphier_fi2c_stop(priv);
 237         } else {
 238 complete:
 239                 priv->enabled_irqs = 0;
 240                 uniphier_fi2c_set_irqs(priv);
 241                 complete(&priv->comp);
 242         }
 243
 244 handled:
 245         uniphier_fi2c_clear_irqs(priv);
 246
 247         return IRQ_HANDLED;
 248 }
 249
 250 static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr)
 251 {
 252         priv->enabled_irqs |= UNIPHIER_FI2C_INT_TE;
 253         /* do not use TX byte counter */
 254         writel(0, priv->membase + UNIPHIER_FI2C_TBC);
 255         /* set slave address */
 256         writel(UNIPHIER_FI2C_DTTX_CMD | addr << 1,
 257                priv->membase + UNIPHIER_FI2C_DTTX);
 258         /* first chunk of data */
 259         uniphier_fi2c_fill_txfifo(priv, true);
 260 }
 261
 262 static void uniphier_fi2c_rx_init(struct uniphier_fi2c_priv *priv, u16 addr)
 263 {
 264         priv->flags |= UNIPHIER_FI2C_RD;
 265
 266         if (likely(priv->len < 256)) {
 267                 /*
 268                  * If possible, use RX byte counter.
 269                  * It can automatically handle NACK for the last byte.
 270                  */
 271                 writel(priv->len, priv->membase + UNIPHIER_FI2C_RBC);
 272                 priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF |
 273                                       UNIPHIER_FI2C_INT_RB;
 274         } else {
 275                 /*
 276                  * The byte counter can not count over 256.  In this case,
 277                  * do not use it at all.  Drain data when FIFO gets full,
 278                  * but treat the last portion as a special case.
 279                  */
 280                 writel(0, priv->membase + UNIPHIER_FI2C_RBC);
 281                 priv->flags |= UNIPHIER_FI2C_MANUAL_NACK;
 282                 priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF;
 283         }
 284
 285         /* set slave address with RD bit */
 286         writel(UNIPHIER_FI2C_DTTX_CMD | UNIPHIER_FI2C_DTTX_RD | addr << 1,
 287                priv->membase + UNIPHIER_FI2C_DTTX);
 288 }
 289
 290 static void uniphier_fi2c_reset(struct uniphier_fi2c_priv *priv)
 291 {
 292         writel(UNIPHIER_FI2C_RST_RST, priv->membase + UNIPHIER_FI2C_RST);
 293 }
 294
 295 static void uniphier_fi2c_prepare_operation(struct uniphier_fi2c_priv *priv)
 296 {
 297         writel(UNIPHIER_FI2C_BRST_FOEN | UNIPHIER_FI2C_BRST_RSCL,
 298                priv->membase + UNIPHIER_FI2C_BRST);
 299 }
 300
 301 static void uniphier_fi2c_recover(struct uniphier_fi2c_priv *priv)
 302 {
 303         uniphier_fi2c_reset(priv);
 304         i2c_recover_bus(&priv->adap);
 305 }
 306
 307 static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
 308                                          struct i2c_msg *msg, bool stop)
 309 {
 310         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 311         bool is_read = msg->flags & I2C_M_RD;
 312         unsigned long time_left;
 313
 314         dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, stop=%d\n",
 315                 is_read ? "receive" : "transmit", msg->addr, msg->len, stop);
 316
 317         priv->len = msg->len;
 318         priv->buf = msg->buf;
 319         priv->enabled_irqs = UNIPHIER_FI2C_INT_FAULTS;
 320         priv->error = 0;
 321         priv->flags = 0;
 322
 323         if (stop)
 324                 priv->flags |= UNIPHIER_FI2C_STOP;
 325
 326         reinit_completion(&priv->comp);
 327         uniphier_fi2c_clear_irqs(priv);
 328         writel(UNIPHIER_FI2C_RST_TBRST | UNIPHIER_FI2C_RST_RBRST,
 329                priv->membase + UNIPHIER_FI2C_RST);      /* reset TX/RX FIFO */
 330
 331         if (is_read)
 332                 uniphier_fi2c_rx_init(priv, msg->addr);
 333         else
 334                 uniphier_fi2c_tx_init(priv, msg->addr);
 335
 336         uniphier_fi2c_set_irqs(priv);
 337
 338         dev_dbg(&adap->dev, "start condition\n");
 339         writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
 340                priv->membase + UNIPHIER_FI2C_CR);
 341
 342         time_left = wait_for_completion_timeout(&priv->comp, adap->timeout);
 343         if (!time_left) {
 344                 dev_err(&adap->dev, "transaction timeout.\n");
 345                 uniphier_fi2c_recover(priv);
 346                 return -ETIMEDOUT;
 347         }
 348         dev_dbg(&adap->dev, "complete\n");
 349
 350         if (unlikely(priv->flags & UNIPHIER_FI2C_DEFER_STOP_COMP)) {
 351                 u32 status = readl(priv->membase + UNIPHIER_FI2C_SR);
 352
 353                 if (!(status & UNIPHIER_FI2C_SR_STS) ||
 354                     status & UNIPHIER_FI2C_SR_BB) {
 355                         dev_err(&adap->dev,
 356                                 "stop condition was not completed.\n");
 357                         uniphier_fi2c_recover(priv);
 358                         return -EBUSY;
 359                 }
 360         }
 361
 362         return priv->error;
 363 }
 364
 365 static int uniphier_fi2c_check_bus_busy(struct i2c_adapter *adap)
 366 {
 367         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 368
 369         if (readl(priv->membase + UNIPHIER_FI2C_SR) & UNIPHIER_FI2C_SR_DB) {
 370                 if (priv->busy_cnt++ > 3) {
 371                         /*
 372                          * If bus busy continues too long, it is probably
 373                          * in a wrong state.  Try bus recovery.
 374                          */
 375                         uniphier_fi2c_recover(priv);
 376                         priv->busy_cnt = 0;
 377                 }
 378
 379                 return -EAGAIN;
 380         }
 381
 382         priv->busy_cnt = 0;
 383         return 0;
 384 }
 385
 386 static int uniphier_fi2c_master_xfer(struct i2c_adapter *adap,
 387                                      struct i2c_msg *msgs, int num)
 388 {
 389         struct i2c_msg *msg, *emsg = msgs + num;
 390         int ret;
 391
 392         ret = uniphier_fi2c_check_bus_busy(adap);
 393         if (ret)
 394                 return ret;
 395
 396         for (msg = msgs; msg < emsg; msg++) {
 397                 /* Emit STOP if it is the last message or I2C_M_STOP is set. */
 398                 bool stop = (msg + 1 == emsg) || (msg->flags & I2C_M_STOP);
 399
 400                 ret = uniphier_fi2c_master_xfer_one(adap, msg, stop);
 401                 if (ret)
 402                         return ret;
 403         }
 404
 405         return num;
 406 }
 407
 408 static u32 uniphier_fi2c_functionality(struct i2c_adapter *adap)
 409 {
 410         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 411 }
 412
 413 static const struct i2c_algorithm uniphier_fi2c_algo = {
 414         .master_xfer = uniphier_fi2c_master_xfer,
 415         .functionality = uniphier_fi2c_functionality,
 416 };
 417
 418 static int uniphier_fi2c_get_scl(struct i2c_adapter *adap)
 419 {
 420         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 421
 422         return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
 423                                                         UNIPHIER_FI2C_BM_SCLS);
 424 }
 425
 426 static void uniphier_fi2c_set_scl(struct i2c_adapter *adap, int val)
 427 {
 428         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 429
 430         writel(val ? UNIPHIER_FI2C_BRST_RSCL : 0,
 431                priv->membase + UNIPHIER_FI2C_BRST);
 432 }
 433
 434 static int uniphier_fi2c_get_sda(struct i2c_adapter *adap)
 435 {
 436         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 437
 438         return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
 439                                                         UNIPHIER_FI2C_BM_SDAS);
 440 }
 441
 442 static void uniphier_fi2c_unprepare_recovery(struct i2c_adapter *adap)
 443 {
 444         uniphier_fi2c_prepare_operation(i2c_get_adapdata(adap));
 445 }
 446
 447 static struct i2c_bus_recovery_info uniphier_fi2c_bus_recovery_info = {
 448         .recover_bus = i2c_generic_scl_recovery,
 449         .get_scl = uniphier_fi2c_get_scl,
 450         .set_scl = uniphier_fi2c_set_scl,
 451         .get_sda = uniphier_fi2c_get_sda,
 452         .unprepare_recovery = uniphier_fi2c_unprepare_recovery,
 453 };
 454
 455 static int uniphier_fi2c_clk_init(struct device *dev,
 456                                   struct uniphier_fi2c_priv *priv)
 457 {
 458         struct device_node *np = dev->of_node;
 459         unsigned long clk_rate;
 460         u32 bus_speed, clk_count;
 461         int ret;
 462
 463         if (of_property_read_u32(np, "clock-frequency", &bus_speed))
 464                 bus_speed = UNIPHIER_FI2C_DEFAULT_SPEED;
 465
 466         if (bus_speed > UNIPHIER_FI2C_MAX_SPEED)
 467                 bus_speed = UNIPHIER_FI2C_MAX_SPEED;
 468
 469         /* Get input clk rate through clk driver */
 470         priv->clk = devm_clk_get(dev, NULL);
 471         if (IS_ERR(priv->clk)) {
 472                 dev_err(dev, "failed to get clock\n");
 473                 return PTR_ERR(priv->clk);
 474         }
 475
 476         ret = clk_prepare_enable(priv->clk);
 477         if (ret)
 478                 return ret;
 479
 480         clk_rate = clk_get_rate(priv->clk);
 481
 482         uniphier_fi2c_reset(priv);
 483
 484         clk_count = clk_rate / bus_speed;
 485
 486         writel(clk_count, priv->membase + UNIPHIER_FI2C_CYC);
 487         writel(clk_count / 2, priv->membase + UNIPHIER_FI2C_LCTL);
 488         writel(clk_count / 2, priv->membase + UNIPHIER_FI2C_SSUT);
 489         writel(clk_count / 16, priv->membase + UNIPHIER_FI2C_DSUT);
 490
 491         uniphier_fi2c_prepare_operation(priv);
 492
 493         return 0;
 494 }
 495
 496 static int uniphier_fi2c_probe(struct platform_device *pdev)
 497 {
 498         struct device *dev = &pdev->dev;
 499         struct uniphier_fi2c_priv *priv;
 500         struct resource *regs;
 501         int irq;
 502         int ret;
 503
 504         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 505         if (!priv)
 506                 return -ENOMEM;
 507
 508         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 509         priv->membase = devm_ioremap_resource(dev, regs);
 510         if (IS_ERR(priv->membase))
 511                 return PTR_ERR(priv->membase);
 512
 513         irq = platform_get_irq(pdev, 0);
 514         if (irq < 0) {
 515                 dev_err(dev, "failed to get IRQ number");
 516                 return irq;
 517         }
 518
 519         init_completion(&priv->comp);
 520         priv->adap.owner = THIS_MODULE;
 521         priv->adap.algo = &uniphier_fi2c_algo;
 522         priv->adap.dev.parent = dev;
 523         priv->adap.dev.of_node = dev->of_node;
 524         strlcpy(priv->adap.name, "UniPhier FI2C", sizeof(priv->adap.name));
 525         priv->adap.bus_recovery_info = &uniphier_fi2c_bus_recovery_info;
 526         i2c_set_adapdata(&priv->adap, priv);
 527         platform_set_drvdata(pdev, priv);
 528
 529         ret = uniphier_fi2c_clk_init(dev, priv);
 530         if (ret)
 531                 return ret;
 532
 533         ret = devm_request_irq(dev, irq, uniphier_fi2c_interrupt, 0,
 534                                pdev->name, priv);
 535         if (ret) {
 536                 dev_err(dev, "failed to request irq %d\n", irq);
 537                 goto err;
 538         }
 539
 540         ret = i2c_add_adapter(&priv->adap);
 541         if (ret) {
 542                 dev_err(dev, "failed to add I2C adapter\n");
 543                 goto err;
 544         }
 545
 546 err:
 547         if (ret)
 548                 clk_disable_unprepare(priv->clk);
 549
 550         return ret;
 551 }
 552
 553 static int uniphier_fi2c_remove(struct platform_device *pdev)
 554 {
 555         struct uniphier_fi2c_priv *priv = platform_get_drvdata(pdev);
 556
 557         i2c_del_adapter(&priv->adap);
 558         clk_disable_unprepare(priv->clk);
 559
 560         return 0;
 561 }
 562
 563 static const struct of_device_id uniphier_fi2c_match[] = {
 564         { .compatible = "socionext,uniphier-fi2c" },
 565         { /* sentinel */ }
 566 };
 567 MODULE_DEVICE_TABLE(of, uniphier_fi2c_match);
 568
 569 static struct platform_driver uniphier_fi2c_drv = {
 570         .probe  = uniphier_fi2c_probe,
 571         .remove = uniphier_fi2c_remove,
 572         .driver = {
 573                 .name  = "uniphier-fi2c",
 574                 .of_match_table = uniphier_fi2c_match,
 575         },
 576 };
 577 module_platform_driver(uniphier_fi2c_drv);
 578
 579 MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
 580 MODULE_DESCRIPTION("UniPhier FIFO-builtin I2C bus driver");
 581 MODULE_LICENSE("GPL");