drivers/i2c/busses/i2c-rk3x.c

   1 /*
   2  * Driver for I2C adapter in Rockchip RK3xxx SoC
   3  *
   4  * Max Schwarz <max.schwarz@online.de>
   5  * based on the patches by Rockchip Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/i2c.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/errno.h>
  17 #include <linux/err.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/io.h>
  20 #include <linux/of_address.h>
  21 #include <linux/of_irq.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/clk.h>
  24 #include <linux/wait.h>
  25 #include <linux/mfd/syscon.h>
  26 #include <linux/regmap.h>
  27
  28
  29 /* Register Map */
  30 #define REG_CON        0x00 /* control register */
  31 #define REG_CLKDIV     0x04 /* clock divisor register */
  32 #define REG_MRXADDR    0x08 /* slave address for REGISTER_TX */
  33 #define REG_MRXRADDR   0x0c /* slave register address for REGISTER_TX */
  34 #define REG_MTXCNT     0x10 /* number of bytes to be transmitted */
  35 #define REG_MRXCNT     0x14 /* number of bytes to be received */
  36 #define REG_IEN        0x18 /* interrupt enable */
  37 #define REG_IPD        0x1c /* interrupt pending */
  38 #define REG_FCNT       0x20 /* finished count */
  39
  40 /* Data buffer offsets */
  41 #define TXBUFFER_BASE 0x100
  42 #define RXBUFFER_BASE 0x200
  43
  44 /* REG_CON bits */
  45 #define REG_CON_EN        BIT(0)
  46 enum {
  47         REG_CON_MOD_TX = 0,      /* transmit data */
  48         REG_CON_MOD_REGISTER_TX, /* select register and restart */
  49         REG_CON_MOD_RX,          /* receive data */
  50         REG_CON_MOD_REGISTER_RX, /* broken: transmits read addr AND writes
  51                                   * register addr */
  52 };
  53 #define REG_CON_MOD(mod)  ((mod) << 1)
  54 #define REG_CON_MOD_MASK  (BIT(1) | BIT(2))
  55 #define REG_CON_START     BIT(3)
  56 #define REG_CON_STOP      BIT(4)
  57 #define REG_CON_LASTACK   BIT(5) /* 1: send NACK after last received byte */
  58 #define REG_CON_ACTACK    BIT(6) /* 1: stop if NACK is received */
  59
  60 /* REG_MRXADDR bits */
  61 #define REG_MRXADDR_VALID(x) BIT(24 + (x)) /* [x*8+7:x*8] of MRX[R]ADDR valid */
  62
  63 /* REG_IEN/REG_IPD bits */
  64 #define REG_INT_BTF       BIT(0) /* a byte was transmitted */
  65 #define REG_INT_BRF       BIT(1) /* a byte was received */
  66 #define REG_INT_MBTF      BIT(2) /* master data transmit finished */
  67 #define REG_INT_MBRF      BIT(3) /* master data receive finished */
  68 #define REG_INT_START     BIT(4) /* START condition generated */
  69 #define REG_INT_STOP      BIT(5) /* STOP condition generated */
  70 #define REG_INT_NAKRCV    BIT(6) /* NACK received */
  71 #define REG_INT_ALL       0x7f
  72
  73 /* Constants */
  74 #define WAIT_TIMEOUT      200 /* ms */
  75 #define DEFAULT_SCL_RATE  (100 * 1000) /* Hz */
  76
  77 enum rk3x_i2c_state {
  78         STATE_IDLE,
  79         STATE_START,
  80         STATE_READ,
  81         STATE_WRITE,
  82         STATE_STOP
  83 };
  84
  85 /**
  86  * @grf_offset: offset inside the grf regmap for setting the i2c type
  87  */
  88 struct rk3x_i2c_soc_data {
  89         int grf_offset;
  90 };
  91
  92 struct rk3x_i2c {
  93         struct i2c_adapter adap;
  94         struct device *dev;
  95         struct rk3x_i2c_soc_data *soc_data;
  96
  97         /* Hardware resources */
  98         void __iomem *regs;
  99         struct clk *clk;
 100
 101         /* Settings */
 102         unsigned int scl_frequency;
 103
 104         /* Synchronization & notification */
 105         spinlock_t lock;
 106         wait_queue_head_t wait;
 107         bool busy;
 108
 109         /* Current message */
 110         struct i2c_msg *msg;
 111         u8 addr;
 112         unsigned int mode;
 113         bool is_last_msg;
 114
 115         /* I2C state machine */
 116         enum rk3x_i2c_state state;
 117         unsigned int processed; /* sent/received bytes */
 118         int error;
 119 };
 120
 121 static inline void i2c_writel(struct rk3x_i2c *i2c, u32 value,
 122                               unsigned int offset)
 123 {
 124         writel(value, i2c->regs + offset);
 125 }
 126
 127 static inline u32 i2c_readl(struct rk3x_i2c *i2c, unsigned int offset)
 128 {
 129         return readl(i2c->regs + offset);
 130 }
 131
 132 /* Reset all interrupt pending bits */
 133 static inline void rk3x_i2c_clean_ipd(struct rk3x_i2c *i2c)
 134 {
 135         i2c_writel(i2c, REG_INT_ALL, REG_IPD);
 136 }
 137
 138 /**
 139  * Generate a START condition, which triggers a REG_INT_START interrupt.
 140  */
 141 static void rk3x_i2c_start(struct rk3x_i2c *i2c)
 142 {
 143         u32 val;
 144
 145         rk3x_i2c_clean_ipd(i2c);
 146         i2c_writel(i2c, REG_INT_START, REG_IEN);
 147
 148         /* enable adapter with correct mode, send START condition */
 149         val = REG_CON_EN | REG_CON_MOD(i2c->mode) | REG_CON_START;
 150
 151         /* if we want to react to NACK, set ACTACK bit */
 152         if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
 153                 val |= REG_CON_ACTACK;
 154
 155         i2c_writel(i2c, val, REG_CON);
 156 }
 157
 158 /**
 159  * Generate a STOP condition, which triggers a REG_INT_STOP interrupt.
 160  *
 161  * @error: Error code to return in rk3x_i2c_xfer
 162  */
 163 static void rk3x_i2c_stop(struct rk3x_i2c *i2c, int error)
 164 {
 165         unsigned int ctrl;
 166
 167         i2c->processed = 0;
 168         i2c->msg = NULL;
 169         i2c->error = error;
 170
 171         if (i2c->is_last_msg) {
 172                 /* Enable stop interrupt */
 173                 i2c_writel(i2c, REG_INT_STOP, REG_IEN);
 174
 175                 i2c->state = STATE_STOP;
 176
 177                 ctrl = i2c_readl(i2c, REG_CON);
 178                 ctrl |= REG_CON_STOP;
 179                 i2c_writel(i2c, ctrl, REG_CON);
 180         } else {
 181                 /* Signal rk3x_i2c_xfer to start the next message. */
 182                 i2c->busy = false;
 183                 i2c->state = STATE_IDLE;
 184
 185                 /*
 186                  * The HW is actually not capable of REPEATED START. But we can
 187                  * get the intended effect by resetting its internal state
 188                  * and issuing an ordinary START.
 189                  */
 190                 i2c_writel(i2c, 0, REG_CON);
 191
 192                 /* signal that we are finished with the current msg */
 193                 wake_up(&i2c->wait);
 194         }
 195 }
 196
 197 /**
 198  * Setup a read according to i2c->msg
 199  */
 200 static void rk3x_i2c_prepare_read(struct rk3x_i2c *i2c)
 201 {
 202         unsigned int len = i2c->msg->len - i2c->processed;
 203         u32 con;
 204
 205         con = i2c_readl(i2c, REG_CON);
 206
 207         /*
 208          * The hw can read up to 32 bytes at a time. If we need more than one
 209          * chunk, send an ACK after the last byte of the current chunk.
 210          */
 211         if (unlikely(len > 32)) {
 212                 len = 32;
 213                 con &= ~REG_CON_LASTACK;
 214         } else {
 215                 con |= REG_CON_LASTACK;
 216         }
 217
 218         /* make sure we are in plain RX mode if we read a second chunk */
 219         if (i2c->processed != 0) {
 220                 con &= ~REG_CON_MOD_MASK;
 221                 con |= REG_CON_MOD(REG_CON_MOD_RX);
 222         }
 223
 224         i2c_writel(i2c, con, REG_CON);
 225         i2c_writel(i2c, len, REG_MRXCNT);
 226 }
 227
 228 /**
 229  * Fill the transmit buffer with data from i2c->msg
 230  */
 231 static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c)
 232 {
 233         unsigned int i, j;
 234         u32 cnt = 0;
 235         u32 val;
 236         u8 byte;
 237
 238         for (i = 0; i < 8; ++i) {
 239                 val = 0;
 240                 for (j = 0; j < 4; ++j) {
 241                         if (i2c->processed == i2c->msg->len)
 242                                 break;
 243
 244                         if (i2c->processed == 0 && cnt == 0)
 245                                 byte = (i2c->addr & 0x7f) << 1;
 246                         else
 247                                 byte = i2c->msg->buf[i2c->processed++];
 248
 249                         val |= byte << (j * 8);
 250                         cnt++;
 251                 }
 252
 253                 i2c_writel(i2c, val, TXBUFFER_BASE + 4 * i);
 254
 255                 if (i2c->processed == i2c->msg->len)
 256                         break;
 257         }
 258
 259         i2c_writel(i2c, cnt, REG_MTXCNT);
 260 }
 261
 262
 263 /* IRQ handlers for individual states */
 264
 265 static void rk3x_i2c_handle_start(struct rk3x_i2c *i2c, unsigned int ipd)
 266 {
 267         if (!(ipd & REG_INT_START)) {
 268                 rk3x_i2c_stop(i2c, -EIO);
 269                 dev_warn(i2c->dev, "unexpected irq in START: 0x%x\n", ipd);
 270                 rk3x_i2c_clean_ipd(i2c);
 271                 return;
 272         }
 273
 274         /* ack interrupt */
 275         i2c_writel(i2c, REG_INT_START, REG_IPD);
 276
 277         /* disable start bit */
 278         i2c_writel(i2c, i2c_readl(i2c, REG_CON) & ~REG_CON_START, REG_CON);
 279
 280         /* enable appropriate interrupts and transition */
 281         if (i2c->mode == REG_CON_MOD_TX) {
 282                 i2c_writel(i2c, REG_INT_MBTF | REG_INT_NAKRCV, REG_IEN);
 283                 i2c->state = STATE_WRITE;
 284                 rk3x_i2c_fill_transmit_buf(i2c);
 285         } else {
 286                 /* in any other case, we are going to be reading. */
 287                 i2c_writel(i2c, REG_INT_MBRF | REG_INT_NAKRCV, REG_IEN);
 288                 i2c->state = STATE_READ;
 289                 rk3x_i2c_prepare_read(i2c);
 290         }
 291 }
 292
 293 static void rk3x_i2c_handle_write(struct rk3x_i2c *i2c, unsigned int ipd)
 294 {
 295         if (!(ipd & REG_INT_MBTF)) {
 296                 rk3x_i2c_stop(i2c, -EIO);
 297                 dev_err(i2c->dev, "unexpected irq in WRITE: 0x%x\n", ipd);
 298                 rk3x_i2c_clean_ipd(i2c);
 299                 return;
 300         }
 301
 302         /* ack interrupt */
 303         i2c_writel(i2c, REG_INT_MBTF, REG_IPD);
 304
 305         /* are we finished? */
 306         if (i2c->processed == i2c->msg->len)
 307                 rk3x_i2c_stop(i2c, i2c->error);
 308         else
 309                 rk3x_i2c_fill_transmit_buf(i2c);
 310 }
 311
 312 static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd)
 313 {
 314         unsigned int i;
 315         unsigned int len = i2c->msg->len - i2c->processed;
 316         u32 uninitialized_var(val);
 317         u8 byte;
 318
 319         /* we only care for MBRF here. */
 320         if (!(ipd & REG_INT_MBRF))
 321                 return;
 322
 323         /* ack interrupt */
 324         i2c_writel(i2c, REG_INT_MBRF, REG_IPD);
 325
 326         /* read the data from receive buffer */
 327         for (i = 0; i < len; ++i) {
 328                 if (i % 4 == 0)
 329                         val = i2c_readl(i2c, RXBUFFER_BASE + (i / 4) * 4);
 330
 331                 byte = (val >> ((i % 4) * 8)) & 0xff;
 332                 i2c->msg->buf[i2c->processed++] = byte;
 333         }
 334
 335         /* are we finished? */
 336         if (i2c->processed == i2c->msg->len)
 337                 rk3x_i2c_stop(i2c, i2c->error);
 338         else
 339                 rk3x_i2c_prepare_read(i2c);
 340 }
 341
 342 static void rk3x_i2c_handle_stop(struct rk3x_i2c *i2c, unsigned int ipd)
 343 {
 344         unsigned int con;
 345
 346         if (!(ipd & REG_INT_STOP)) {
 347                 rk3x_i2c_stop(i2c, -EIO);
 348                 dev_err(i2c->dev, "unexpected irq in STOP: 0x%x\n", ipd);
 349                 rk3x_i2c_clean_ipd(i2c);
 350                 return;
 351         }
 352
 353         /* ack interrupt */
 354         i2c_writel(i2c, REG_INT_STOP, REG_IPD);
 355
 356         /* disable STOP bit */
 357         con = i2c_readl(i2c, REG_CON);
 358         con &= ~REG_CON_STOP;
 359         i2c_writel(i2c, con, REG_CON);
 360
 361         i2c->busy = false;
 362         i2c->state = STATE_IDLE;
 363
 364         /* signal rk3x_i2c_xfer that we are finished */
 365         wake_up(&i2c->wait);
 366 }
 367
 368 static irqreturn_t rk3x_i2c_irq(int irqno, void *dev_id)
 369 {
 370         struct rk3x_i2c *i2c = dev_id;
 371         unsigned int ipd;
 372
 373         spin_lock(&i2c->lock);
 374
 375         ipd = i2c_readl(i2c, REG_IPD);
 376         if (i2c->state == STATE_IDLE) {
 377                 dev_warn(i2c->dev, "irq in STATE_IDLE, ipd = 0x%x\n", ipd);
 378                 rk3x_i2c_clean_ipd(i2c);
 379                 goto out;
 380         }
 381
 382         dev_dbg(i2c->dev, "IRQ: state %d, ipd: %x\n", i2c->state, ipd);
 383
 384         /* Clean interrupt bits we don't care about */
 385         ipd &= ~(REG_INT_BRF | REG_INT_BTF);
 386
 387         if (ipd & REG_INT_NAKRCV) {
 388                 /*
 389                  * We got a NACK in the last operation. Depending on whether
 390                  * IGNORE_NAK is set, we have to stop the operation and report
 391                  * an error.
 392                  */
 393                 i2c_writel(i2c, REG_INT_NAKRCV, REG_IPD);
 394
 395                 ipd &= ~REG_INT_NAKRCV;
 396
 397                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
 398                         rk3x_i2c_stop(i2c, -ENXIO);
 399         }
 400
 401         /* is there anything left to handle? */
 402         if (unlikely(ipd == 0))
 403                 goto out;
 404
 405         switch (i2c->state) {
 406         case STATE_START:
 407                 rk3x_i2c_handle_start(i2c, ipd);
 408                 break;
 409         case STATE_WRITE:
 410                 rk3x_i2c_handle_write(i2c, ipd);
 411                 break;
 412         case STATE_READ:
 413                 rk3x_i2c_handle_read(i2c, ipd);
 414                 break;
 415         case STATE_STOP:
 416                 rk3x_i2c_handle_stop(i2c, ipd);
 417                 break;
 418         case STATE_IDLE:
 419                 break;
 420         }
 421
 422 out:
 423         spin_unlock(&i2c->lock);
 424         return IRQ_HANDLED;
 425 }
 426
 427 static void rk3x_i2c_set_scl_rate(struct rk3x_i2c *i2c, unsigned long scl_rate)
 428 {
 429         unsigned long i2c_rate = clk_get_rate(i2c->clk);
 430         unsigned int div;
 431
 432         /* SCL rate = (clk rate) / (8 * DIV) */
 433         div = DIV_ROUND_UP(i2c_rate, scl_rate * 8);
 434
 435         /* The lower and upper half of the CLKDIV reg describe the length of
 436          * SCL low & high periods. */
 437         div = DIV_ROUND_UP(div, 2);
 438
 439         i2c_writel(i2c, (div << 16) | (div & 0xffff), REG_CLKDIV);
 440 }
 441
 442 /**
 443  * Setup I2C registers for an I2C operation specified by msgs, num.
 444  *
 445  * Must be called with i2c->lock held.
 446  *
 447  * @msgs: I2C msgs to process
 448  * @num: Number of msgs
 449  *
 450  * returns: Number of I2C msgs processed or negative in case of error
 451  */
 452 static int rk3x_i2c_setup(struct rk3x_i2c *i2c, struct i2c_msg *msgs, int num)
 453 {
 454         u32 addr = (msgs[0].addr & 0x7f) << 1;
 455         int ret = 0;
 456
 457         /*
 458          * The I2C adapter can issue a small (len < 4) write packet before
 459          * reading. This speeds up SMBus-style register reads.
 460          * The MRXADDR/MRXRADDR hold the slave address and the slave register
 461          * address in this case.
 462          */
 463
 464         if (num >= 2 && msgs[0].len < 4 &&
 465             !(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) {
 466                 u32 reg_addr = 0;
 467                 int i;
 468
 469                 dev_dbg(i2c->dev, "Combined write/read from addr 0x%x\n",
 470                         addr >> 1);
 471
 472                 /* Fill MRXRADDR with the register address(es) */
 473                 for (i = 0; i < msgs[0].len; ++i) {
 474                         reg_addr |= msgs[0].buf[i] << (i * 8);
 475                         reg_addr |= REG_MRXADDR_VALID(i);
 476                 }
 477
 478                 /* msgs[0] is handled by hw. */
 479                 i2c->msg = &msgs[1];
 480
 481                 i2c->mode = REG_CON_MOD_REGISTER_TX;
 482
 483                 i2c_writel(i2c, addr | REG_MRXADDR_VALID(0), REG_MRXADDR);
 484                 i2c_writel(i2c, reg_addr, REG_MRXRADDR);
 485
 486                 ret = 2;
 487         } else {
 488                 /*
 489                  * We'll have to do it the boring way and process the msgs
 490                  * one-by-one.
 491                  */
 492
 493                 if (msgs[0].flags & I2C_M_RD) {
 494                         addr |= 1; /* set read bit */
 495
 496                         /*
 497                          * We have to transmit the slave addr first. Use
 498                          * MOD_REGISTER_TX for that purpose.
 499                          */
 500                         i2c->mode = REG_CON_MOD_REGISTER_TX;
 501                         i2c_writel(i2c, addr | REG_MRXADDR_VALID(0),
 502                                    REG_MRXADDR);
 503                         i2c_writel(i2c, 0, REG_MRXRADDR);
 504                 } else {
 505                         i2c->mode = REG_CON_MOD_TX;
 506                 }
 507
 508                 i2c->msg = &msgs[0];
 509
 510                 ret = 1;
 511         }
 512
 513         i2c->addr = msgs[0].addr;
 514         i2c->busy = true;
 515         i2c->state = STATE_START;
 516         i2c->processed = 0;
 517         i2c->error = 0;
 518
 519         rk3x_i2c_clean_ipd(i2c);
 520
 521         return ret;
 522 }
 523
 524 static int rk3x_i2c_xfer(struct i2c_adapter *adap,
 525                          struct i2c_msg *msgs, int num)
 526 {
 527         struct rk3x_i2c *i2c = (struct rk3x_i2c *)adap->algo_data;
 528         unsigned long timeout, flags;
 529         int ret = 0;
 530         int i;
 531
 532         spin_lock_irqsave(&i2c->lock, flags);
 533
 534         clk_enable(i2c->clk);
 535
 536         /* The clock rate might have changed, so setup the divider again */
 537         rk3x_i2c_set_scl_rate(i2c, i2c->scl_frequency);
 538
 539         i2c->is_last_msg = false;
 540
 541         /*
 542          * Process msgs. We can handle more than one message at once (see
 543          * rk3x_i2c_setup()).
 544          */
 545         for (i = 0; i < num; i += ret) {
 546                 ret = rk3x_i2c_setup(i2c, msgs + i, num - i);
 547
 548                 if (ret < 0) {
 549                         dev_err(i2c->dev, "rk3x_i2c_setup() failed\n");
 550                         break;
 551                 }
 552
 553                 if (i + ret >= num)
 554                         i2c->is_last_msg = true;
 555
 556                 spin_unlock_irqrestore(&i2c->lock, flags);
 557
 558                 rk3x_i2c_start(i2c);
 559
 560                 timeout = wait_event_timeout(i2c->wait, !i2c->busy,
 561                                              msecs_to_jiffies(WAIT_TIMEOUT));
 562
 563                 spin_lock_irqsave(&i2c->lock, flags);
 564
 565                 if (timeout == 0) {
 566                         dev_err(i2c->dev, "timeout, ipd: 0x%02x, state: %d\n",
 567                                 i2c_readl(i2c, REG_IPD), i2c->state);
 568
 569                         /* Force a STOP condition without interrupt */
 570                         i2c_writel(i2c, 0, REG_IEN);
 571                         i2c_writel(i2c, REG_CON_EN | REG_CON_STOP, REG_CON);
 572
 573                         i2c->state = STATE_IDLE;
 574
 575                         ret = -ETIMEDOUT;
 576                         break;
 577                 }
 578
 579                 if (i2c->error) {
 580                         ret = i2c->error;
 581                         break;
 582                 }
 583         }
 584
 585         clk_disable(i2c->clk);
 586         spin_unlock_irqrestore(&i2c->lock, flags);
 587
 588         return ret;
 589 }
 590
 591 static u32 rk3x_i2c_func(struct i2c_adapter *adap)
 592 {
 593         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 594 }
 595
 596 static const struct i2c_algorithm rk3x_i2c_algorithm = {
 597         .master_xfer            = rk3x_i2c_xfer,
 598         .functionality          = rk3x_i2c_func,
 599 };
 600
 601 static struct rk3x_i2c_soc_data soc_data[3] = {
 602         { .grf_offset = 0x154 }, /* rk3066 */
 603         { .grf_offset = 0x0a4 }, /* rk3188 */
 604         { .grf_offset = -1 },    /* no I2C switching needed */
 605 };
 606
 607 static const struct of_device_id rk3x_i2c_match[] = {
 608         { .compatible = "rockchip,rk3066-i2c", .data = (void *)&soc_data[0] },
 609         { .compatible = "rockchip,rk3188-i2c", .data = (void *)&soc_data[1] },
 610         { .compatible = "rockchip,rk3288-i2c", .data = (void *)&soc_data[2] },
 611         {},
 612 };
 613
 614 static int rk3x_i2c_probe(struct platform_device *pdev)
 615 {
 616         struct device_node *np = pdev->dev.of_node;
 617         const struct of_device_id *match;
 618         struct rk3x_i2c *i2c;
 619         struct resource *mem;
 620         int ret = 0;
 621         int bus_nr;
 622         u32 value;
 623         int irq;
 624
 625         i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL);
 626         if (!i2c)
 627                 return -ENOMEM;
 628
 629         match = of_match_node(rk3x_i2c_match, np);
 630         i2c->soc_data = (struct rk3x_i2c_soc_data *)match->data;
 631
 632         if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
 633                                  &i2c->scl_frequency)) {
 634                 dev_info(&pdev->dev, "using default SCL frequency: %d\n",
 635                          DEFAULT_SCL_RATE);
 636                 i2c->scl_frequency = DEFAULT_SCL_RATE;
 637         }
 638
 639         if (i2c->scl_frequency == 0 || i2c->scl_frequency > 400 * 1000) {
 640                 dev_warn(&pdev->dev, "invalid SCL frequency specified.\n");
 641                 dev_warn(&pdev->dev, "using default SCL frequency: %d\n",
 642                          DEFAULT_SCL_RATE);
 643                 i2c->scl_frequency = DEFAULT_SCL_RATE;
 644         }
 645
 646         strlcpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name));
 647         i2c->adap.owner = THIS_MODULE;
 648         i2c->adap.algo = &rk3x_i2c_algorithm;
 649         i2c->adap.retries = 3;
 650         i2c->adap.dev.of_node = np;
 651         i2c->adap.algo_data = i2c;
 652         i2c->adap.dev.parent = &pdev->dev;
 653
 654         i2c->dev = &pdev->dev;
 655
 656         spin_lock_init(&i2c->lock);
 657         init_waitqueue_head(&i2c->wait);
 658
 659         i2c->clk = devm_clk_get(&pdev->dev, NULL);
 660         if (IS_ERR(i2c->clk)) {
 661                 dev_err(&pdev->dev, "cannot get clock\n");
 662                 return PTR_ERR(i2c->clk);
 663         }
 664
 665         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 666         i2c->regs = devm_ioremap_resource(&pdev->dev, mem);
 667         if (IS_ERR(i2c->regs))
 668                 return PTR_ERR(i2c->regs);
 669
 670         /* Try to set the I2C adapter number from dt */
 671         bus_nr = of_alias_get_id(np, "i2c");
 672
 673         /*
 674          * Switch to new interface if the SoC also offers the old one.
 675          * The control bit is located in the GRF register space.
 676          */
 677         if (i2c->soc_data->grf_offset >= 0) {
 678                 struct regmap *grf;
 679
 680                 grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
 681                 if (IS_ERR(grf)) {
 682                         dev_err(&pdev->dev,
 683                                 "rk3x-i2c needs 'rockchip,grf' property\n");
 684                         return PTR_ERR(grf);
 685                 }
 686
 687                 if (bus_nr < 0) {
 688                         dev_err(&pdev->dev, "rk3x-i2c needs i2cX alias");
 689                         return -EINVAL;
 690                 }
 691
 692                 /* 27+i: write mask, 11+i: value */
 693                 value = BIT(27 + bus_nr) | BIT(11 + bus_nr);
 694
 695                 ret = regmap_write(grf, i2c->soc_data->grf_offset, value);
 696                 if (ret != 0) {
 697                         dev_err(i2c->dev, "Could not write to GRF: %d\n", ret);
 698                         return ret;
 699                 }
 700         }
 701
 702         /* IRQ setup */
 703         irq = platform_get_irq(pdev, 0);
 704         if (irq < 0) {
 705                 dev_err(&pdev->dev, "cannot find rk3x IRQ\n");
 706                 return irq;
 707         }
 708
 709         ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq,
 710                                0, dev_name(&pdev->dev), i2c);
 711         if (ret < 0) {
 712                 dev_err(&pdev->dev, "cannot request IRQ\n");
 713                 return ret;
 714         }
 715
 716         platform_set_drvdata(pdev, i2c);
 717
 718         ret = clk_prepare(i2c->clk);
 719         if (ret < 0) {
 720                 dev_err(&pdev->dev, "Could not prepare clock\n");
 721                 return ret;
 722         }
 723
 724         ret = i2c_add_adapter(&i2c->adap);
 725         if (ret < 0) {
 726                 dev_err(&pdev->dev, "Could not register adapter\n");
 727                 goto err_clk;
 728         }
 729
 730         dev_info(&pdev->dev, "Initialized RK3xxx I2C bus at %p\n", i2c->regs);
 731
 732         return 0;
 733
 734 err_clk:
 735         clk_unprepare(i2c->clk);
 736         return ret;
 737 }
 738
 739 static int rk3x_i2c_remove(struct platform_device *pdev)
 740 {
 741         struct rk3x_i2c *i2c = platform_get_drvdata(pdev);
 742
 743         i2c_del_adapter(&i2c->adap);
 744         clk_unprepare(i2c->clk);
 745
 746         return 0;
 747 }
 748
 749 static struct platform_driver rk3x_i2c_driver = {
 750         .probe   = rk3x_i2c_probe,
 751         .remove  = rk3x_i2c_remove,
 752         .driver  = {
 753                 .owner = THIS_MODULE,
 754                 .name  = "rk3x-i2c",
 755                 .of_match_table = rk3x_i2c_match,
 756         },
 757 };
 758
 759 module_platform_driver(rk3x_i2c_driver);
 760
 761 MODULE_DESCRIPTION("Rockchip RK3xxx I2C Bus driver");
 762 MODULE_AUTHOR("Max Schwarz <max.schwarz@online.de>");
 763 MODULE_LICENSE("GPL v2");