drivers/i2c/busses/i2c-synquacer.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2012 FUJITSU SEMICONDUCTOR LIMITED
   4  */
   5
   6 #include <linux/acpi.h>
   7 #include <linux/clk.h>
   8 #include <linux/delay.h>
   9 #include <linux/device.h>
  10 #include <linux/err.h>
  11 #include <linux/errno.h>
  12 #include <linux/i2c.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/io.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/sched.h>
  19 #include <linux/slab.h>
  20 #include <linux/spinlock.h>
  21
  22 #define WAIT_PCLK(n, rate)      \
  23         ndelay(DIV_ROUND_UP(DIV_ROUND_UP(1000000000, rate), n) + 10)
  24
  25 /* I2C register address definitions */
  26 #define SYNQUACER_I2C_REG_BSR           (0x00 << 2) // Bus Status
  27 #define SYNQUACER_I2C_REG_BCR           (0x01 << 2) // Bus Control
  28 #define SYNQUACER_I2C_REG_CCR           (0x02 << 2) // Clock Control
  29 #define SYNQUACER_I2C_REG_ADR           (0x03 << 2) // Address
  30 #define SYNQUACER_I2C_REG_DAR           (0x04 << 2) // Data
  31 #define SYNQUACER_I2C_REG_CSR           (0x05 << 2) // Expansion CS
  32 #define SYNQUACER_I2C_REG_FSR           (0x06 << 2) // Bus Clock Freq
  33 #define SYNQUACER_I2C_REG_BC2R          (0x07 << 2) // Bus Control 2
  34
  35 /* I2C register bit definitions */
  36 #define SYNQUACER_I2C_BSR_FBT           BIT(0)  // First Byte Transfer
  37 #define SYNQUACER_I2C_BSR_GCA           BIT(1)  // General Call Address
  38 #define SYNQUACER_I2C_BSR_AAS           BIT(2)  // Address as Slave
  39 #define SYNQUACER_I2C_BSR_TRX           BIT(3)  // Transfer/Receive
  40 #define SYNQUACER_I2C_BSR_LRB           BIT(4)  // Last Received Bit
  41 #define SYNQUACER_I2C_BSR_AL            BIT(5)  // Arbitration Lost
  42 #define SYNQUACER_I2C_BSR_RSC           BIT(6)  // Repeated Start Cond.
  43 #define SYNQUACER_I2C_BSR_BB            BIT(7)  // Bus Busy
  44
  45 #define SYNQUACER_I2C_BCR_INT           BIT(0)  // Interrupt
  46 #define SYNQUACER_I2C_BCR_INTE          BIT(1)  // Interrupt Enable
  47 #define SYNQUACER_I2C_BCR_GCAA          BIT(2)  // Gen. Call Access Ack.
  48 #define SYNQUACER_I2C_BCR_ACK           BIT(3)  // Acknowledge
  49 #define SYNQUACER_I2C_BCR_MSS           BIT(4)  // Master Slave Select
  50 #define SYNQUACER_I2C_BCR_SCC           BIT(5)  // Start Condition Cont.
  51 #define SYNQUACER_I2C_BCR_BEIE          BIT(6)  // Bus Error Int Enable
  52 #define SYNQUACER_I2C_BCR_BER           BIT(7)  // Bus Error
  53
  54 #define SYNQUACER_I2C_CCR_CS_MASK       (0x1f)  // CCR Clock Period Sel.
  55 #define SYNQUACER_I2C_CCR_EN            BIT(5)  // Enable
  56 #define SYNQUACER_I2C_CCR_FM            BIT(6)  // Speed Mode Select
  57
  58 #define SYNQUACER_I2C_CSR_CS_MASK       (0x3f)  // CSR Clock Period Sel.
  59
  60 #define SYNQUACER_I2C_BC2R_SCLL         BIT(0)  // SCL Low Drive
  61 #define SYNQUACER_I2C_BC2R_SDAL         BIT(1)  // SDA Low Drive
  62 #define SYNQUACER_I2C_BC2R_SCLS         BIT(4)  // SCL Status
  63 #define SYNQUACER_I2C_BC2R_SDAS         BIT(5)  // SDA Status
  64
  65 /* PCLK frequency */
  66 #define SYNQUACER_I2C_BUS_CLK_FR(rate)  (((rate) / 20000000) + 1)
  67
  68 /* STANDARD MODE frequency */
  69 #define SYNQUACER_I2C_CLK_MASTER_STD(rate)                      \
  70         DIV_ROUND_UP(DIV_ROUND_UP((rate), 100000) - 2, 2)
  71 /* FAST MODE frequency */
  72 #define SYNQUACER_I2C_CLK_MASTER_FAST(rate)                     \
  73         DIV_ROUND_UP((DIV_ROUND_UP((rate), 400000) - 2) * 2, 3)
  74
  75 /* (clkrate <= 18000000) */
  76 /* calculate the value of CS bits in CCR register on standard mode */
  77 #define SYNQUACER_I2C_CCR_CS_STD_MAX_18M(rate)                  \
  78            ((SYNQUACER_I2C_CLK_MASTER_STD(rate) - 65)           \
  79                                         & SYNQUACER_I2C_CCR_CS_MASK)
  80
  81 /* calculate the value of CS bits in CSR register on standard mode */
  82 #define SYNQUACER_I2C_CSR_CS_STD_MAX_18M(rate)          0x00
  83
  84 /* calculate the value of CS bits in CCR register on fast mode */
  85 #define SYNQUACER_I2C_CCR_CS_FAST_MAX_18M(rate)                 \
  86            ((SYNQUACER_I2C_CLK_MASTER_FAST(rate) - 1)           \
  87                                         & SYNQUACER_I2C_CCR_CS_MASK)
  88
  89 /* calculate the value of CS bits in CSR register on fast mode */
  90 #define SYNQUACER_I2C_CSR_CS_FAST_MAX_18M(rate)         0x00
  91
  92 /* (clkrate > 18000000) */
  93 /* calculate the value of CS bits in CCR register on standard mode */
  94 #define SYNQUACER_I2C_CCR_CS_STD_MIN_18M(rate)                  \
  95            ((SYNQUACER_I2C_CLK_MASTER_STD(rate) - 1)            \
  96                                         & SYNQUACER_I2C_CCR_CS_MASK)
  97
  98 /* calculate the value of CS bits in CSR register on standard mode */
  99 #define SYNQUACER_I2C_CSR_CS_STD_MIN_18M(rate)                  \
 100            (((SYNQUACER_I2C_CLK_MASTER_STD(rate) - 1) >> 5)     \
 101                                         & SYNQUACER_I2C_CSR_CS_MASK)
 102
 103 /* calculate the value of CS bits in CCR register on fast mode */
 104 #define SYNQUACER_I2C_CCR_CS_FAST_MIN_18M(rate)                 \
 105            ((SYNQUACER_I2C_CLK_MASTER_FAST(rate) - 1)           \
 106                                         & SYNQUACER_I2C_CCR_CS_MASK)
 107
 108 /* calculate the value of CS bits in CSR register on fast mode */
 109 #define SYNQUACER_I2C_CSR_CS_FAST_MIN_18M(rate)                 \
 110            (((SYNQUACER_I2C_CLK_MASTER_FAST(rate) - 1) >> 5)    \
 111                                         & SYNQUACER_I2C_CSR_CS_MASK)
 112
 113 /* min I2C clock frequency 14M */
 114 #define SYNQUACER_I2C_MIN_CLK_RATE      (14 * 1000000)
 115 /* max I2C clock frequency 200M */
 116 #define SYNQUACER_I2C_MAX_CLK_RATE      (200 * 1000000)
 117 /* I2C clock frequency 18M */
 118 #define SYNQUACER_I2C_CLK_RATE_18M      (18 * 1000000)
 119
 120 #define SYNQUACER_I2C_SPEED_FM          400     // Fast Mode
 121 #define SYNQUACER_I2C_SPEED_SM          100     // Standard Mode
 122
 123 enum i2c_state {
 124         STATE_IDLE,
 125         STATE_START,
 126         STATE_READ,
 127         STATE_WRITE
 128 };
 129
 130 struct synquacer_i2c {
 131         struct completion       completion;
 132
 133         struct i2c_msg          *msg;
 134         u32                     msg_num;
 135         u32                     msg_idx;
 136         u32                     msg_ptr;
 137
 138         int                     irq;
 139         struct device           *dev;
 140         void __iomem            *base;
 141         struct clk              *pclk;
 142         u32                     pclkrate;
 143         u32                     speed_khz;
 144         u32                     timeout_ms;
 145         enum i2c_state          state;
 146         struct i2c_adapter      adapter;
 147 };
 148
 149 static inline int is_lastmsg(struct synquacer_i2c *i2c)
 150 {
 151         return i2c->msg_idx >= (i2c->msg_num - 1);
 152 }
 153
 154 static inline int is_msglast(struct synquacer_i2c *i2c)
 155 {
 156         return i2c->msg_ptr == (i2c->msg->len - 1);
 157 }
 158
 159 static inline int is_msgend(struct synquacer_i2c *i2c)
 160 {
 161         return i2c->msg_ptr >= i2c->msg->len;
 162 }
 163
 164 static inline unsigned long calc_timeout_ms(struct synquacer_i2c *i2c,
 165                                             struct i2c_msg *msgs,
 166                                             int num)
 167 {
 168         unsigned long bit_count = 0;
 169         int i;
 170
 171         for (i = 0; i < num; i++, msgs++)
 172                 bit_count += msgs->len;
 173
 174         return DIV_ROUND_UP((bit_count * 9 + num * 10) * 3, 200) + 10;
 175 }
 176
 177 static void synquacer_i2c_stop(struct synquacer_i2c *i2c, int ret)
 178 {
 179         /*
 180          * clear IRQ (INT=0, BER=0)
 181          * set Stop Condition (MSS=0)
 182          * Interrupt Disable
 183          */
 184         writeb(0, i2c->base + SYNQUACER_I2C_REG_BCR);
 185
 186         i2c->state = STATE_IDLE;
 187
 188         i2c->msg_ptr = 0;
 189         i2c->msg = NULL;
 190         i2c->msg_idx++;
 191         i2c->msg_num = 0;
 192         if (ret)
 193                 i2c->msg_idx = ret;
 194
 195         complete(&i2c->completion);
 196 }
 197
 198 static void synquacer_i2c_hw_init(struct synquacer_i2c *i2c)
 199 {
 200         unsigned char ccr_cs, csr_cs;
 201         u32 rt = i2c->pclkrate;
 202
 203         /* Set own Address */
 204         writeb(0, i2c->base + SYNQUACER_I2C_REG_ADR);
 205
 206         /* Set PCLK frequency */
 207         writeb(SYNQUACER_I2C_BUS_CLK_FR(i2c->pclkrate),
 208                i2c->base + SYNQUACER_I2C_REG_FSR);
 209
 210         switch (i2c->speed_khz) {
 211         case SYNQUACER_I2C_SPEED_FM:
 212                 if (i2c->pclkrate <= SYNQUACER_I2C_CLK_RATE_18M) {
 213                         ccr_cs = SYNQUACER_I2C_CCR_CS_FAST_MAX_18M(rt);
 214                         csr_cs = SYNQUACER_I2C_CSR_CS_FAST_MAX_18M(rt);
 215                 } else {
 216                         ccr_cs = SYNQUACER_I2C_CCR_CS_FAST_MIN_18M(rt);
 217                         csr_cs = SYNQUACER_I2C_CSR_CS_FAST_MIN_18M(rt);
 218                 }
 219
 220                 /* Set Clock and enable, Set fast mode */
 221                 writeb(ccr_cs | SYNQUACER_I2C_CCR_FM |
 222                        SYNQUACER_I2C_CCR_EN,
 223                        i2c->base + SYNQUACER_I2C_REG_CCR);
 224                 writeb(csr_cs, i2c->base + SYNQUACER_I2C_REG_CSR);
 225                 break;
 226         case SYNQUACER_I2C_SPEED_SM:
 227                 if (i2c->pclkrate <= SYNQUACER_I2C_CLK_RATE_18M) {
 228                         ccr_cs = SYNQUACER_I2C_CCR_CS_STD_MAX_18M(rt);
 229                         csr_cs = SYNQUACER_I2C_CSR_CS_STD_MAX_18M(rt);
 230                 } else {
 231                         ccr_cs = SYNQUACER_I2C_CCR_CS_STD_MIN_18M(rt);
 232                         csr_cs = SYNQUACER_I2C_CSR_CS_STD_MIN_18M(rt);
 233                 }
 234
 235                 /* Set Clock and enable, Set standard mode */
 236                 writeb(ccr_cs | SYNQUACER_I2C_CCR_EN,
 237                       i2c->base + SYNQUACER_I2C_REG_CCR);
 238                 writeb(csr_cs, i2c->base + SYNQUACER_I2C_REG_CSR);
 239                 break;
 240         default:
 241                 WARN_ON(1);
 242         }
 243
 244         /* clear IRQ (INT=0, BER=0), Interrupt Disable */
 245         writeb(0, i2c->base + SYNQUACER_I2C_REG_BCR);
 246         writeb(0, i2c->base + SYNQUACER_I2C_REG_BC2R);
 247 }
 248
 249 static void synquacer_i2c_hw_reset(struct synquacer_i2c *i2c)
 250 {
 251         /* Disable clock */
 252         writeb(0, i2c->base + SYNQUACER_I2C_REG_CCR);
 253         writeb(0, i2c->base + SYNQUACER_I2C_REG_CSR);
 254
 255         WAIT_PCLK(100, i2c->pclkrate);
 256 }
 257
 258 static int synquacer_i2c_master_start(struct synquacer_i2c *i2c,
 259                                       struct i2c_msg *pmsg)
 260 {
 261         unsigned char bsr, bcr;
 262
 263         writeb(i2c_8bit_addr_from_msg(pmsg), i2c->base + SYNQUACER_I2C_REG_DAR);
 264
 265         dev_dbg(i2c->dev, "slave:0x%02x\n", pmsg->addr);
 266
 267         /* Generate Start Condition */
 268         bsr = readb(i2c->base + SYNQUACER_I2C_REG_BSR);
 269         bcr = readb(i2c->base + SYNQUACER_I2C_REG_BCR);
 270         dev_dbg(i2c->dev, "bsr:0x%02x, bcr:0x%02x\n", bsr, bcr);
 271
 272         if ((bsr & SYNQUACER_I2C_BSR_BB) &&
 273             !(bcr & SYNQUACER_I2C_BCR_MSS)) {
 274                 dev_dbg(i2c->dev, "bus is busy");
 275                 return -EBUSY;
 276         }
 277
 278         if (bsr & SYNQUACER_I2C_BSR_BB) { /* Bus is busy */
 279                 dev_dbg(i2c->dev, "Continuous Start");
 280                 writeb(bcr | SYNQUACER_I2C_BCR_SCC,
 281                        i2c->base + SYNQUACER_I2C_REG_BCR);
 282         } else {
 283                 if (bcr & SYNQUACER_I2C_BCR_MSS) {
 284                         dev_dbg(i2c->dev, "not in master mode");
 285                         return -EAGAIN;
 286                 }
 287                 dev_dbg(i2c->dev, "Start Condition");
 288                 /* Start Condition + Enable Interrupts */
 289                 writeb(bcr | SYNQUACER_I2C_BCR_MSS |
 290                        SYNQUACER_I2C_BCR_INTE | SYNQUACER_I2C_BCR_BEIE,
 291                        i2c->base + SYNQUACER_I2C_REG_BCR);
 292         }
 293
 294         WAIT_PCLK(10, i2c->pclkrate);
 295
 296         /* get BSR & BCR registers */
 297         bsr = readb(i2c->base + SYNQUACER_I2C_REG_BSR);
 298         bcr = readb(i2c->base + SYNQUACER_I2C_REG_BCR);
 299         dev_dbg(i2c->dev, "bsr:0x%02x, bcr:0x%02x\n", bsr, bcr);
 300
 301         if ((bsr & SYNQUACER_I2C_BSR_AL) ||
 302             !(bcr & SYNQUACER_I2C_BCR_MSS)) {
 303                 dev_dbg(i2c->dev, "arbitration lost\n");
 304                 return -EAGAIN;
 305         }
 306
 307         return 0;
 308 }
 309
 310 static int synquacer_i2c_doxfer(struct synquacer_i2c *i2c,
 311                                 struct i2c_msg *msgs, int num)
 312 {
 313         unsigned char bsr;
 314         unsigned long timeout;
 315         int ret;
 316
 317         synquacer_i2c_hw_init(i2c);
 318         bsr = readb(i2c->base + SYNQUACER_I2C_REG_BSR);
 319         if (bsr & SYNQUACER_I2C_BSR_BB) {
 320                 dev_err(i2c->dev, "cannot get bus (bus busy)\n");
 321                 return -EBUSY;
 322         }
 323
 324         reinit_completion(&i2c->completion);
 325
 326         i2c->msg = msgs;
 327         i2c->msg_num = num;
 328         i2c->msg_ptr = 0;
 329         i2c->msg_idx = 0;
 330         i2c->state = STATE_START;
 331
 332         ret = synquacer_i2c_master_start(i2c, i2c->msg);
 333         if (ret < 0) {
 334                 dev_dbg(i2c->dev, "Address failed: (%d)\n", ret);
 335                 return ret;
 336         }
 337
 338         timeout = wait_for_completion_timeout(&i2c->completion,
 339                                         msecs_to_jiffies(i2c->timeout_ms));
 340         if (timeout == 0) {
 341                 dev_dbg(i2c->dev, "timeout\n");
 342                 return -EAGAIN;
 343         }
 344
 345         ret = i2c->msg_idx;
 346         if (ret != num) {
 347                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 348                 return -EAGAIN;
 349         }
 350
 351         /* wait 2 clock periods to ensure the stop has been through the bus */
 352         udelay(DIV_ROUND_UP(2 * 1000, i2c->speed_khz));
 353
 354         return 0;
 355 }
 356
 357 static irqreturn_t synquacer_i2c_isr(int irq, void *dev_id)
 358 {
 359         struct synquacer_i2c *i2c = dev_id;
 360
 361         unsigned char byte;
 362         unsigned char bsr, bcr;
 363         int ret;
 364
 365         bcr = readb(i2c->base + SYNQUACER_I2C_REG_BCR);
 366         bsr = readb(i2c->base + SYNQUACER_I2C_REG_BSR);
 367         dev_dbg(i2c->dev, "bsr:0x%02x, bcr:0x%02x\n", bsr, bcr);
 368
 369         if (bcr & SYNQUACER_I2C_BCR_BER) {
 370                 dev_err(i2c->dev, "bus error\n");
 371                 synquacer_i2c_stop(i2c, -EAGAIN);
 372                 goto out;
 373         }
 374         if ((bsr & SYNQUACER_I2C_BSR_AL) ||
 375             !(bcr & SYNQUACER_I2C_BCR_MSS)) {
 376                 dev_dbg(i2c->dev, "arbitration lost\n");
 377                 synquacer_i2c_stop(i2c, -EAGAIN);
 378                 goto out;
 379         }
 380
 381         switch (i2c->state) {
 382         case STATE_START:
 383                 if (bsr & SYNQUACER_I2C_BSR_LRB) {
 384                         dev_dbg(i2c->dev, "ack was not received\n");
 385                         synquacer_i2c_stop(i2c, -EAGAIN);
 386                         goto out;
 387                 }
 388
 389                 if (i2c->msg->flags & I2C_M_RD)
 390                         i2c->state = STATE_READ;
 391                 else
 392                         i2c->state = STATE_WRITE;
 393
 394                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 395                         synquacer_i2c_stop(i2c, 0);
 396                         goto out;
 397                 }
 398
 399                 if (i2c->state == STATE_READ)
 400                         goto prepare_read;
 401
 402                 /* fall through */
 403
 404         case STATE_WRITE:
 405                 if (bsr & SYNQUACER_I2C_BSR_LRB) {
 406                         dev_dbg(i2c->dev, "WRITE: No Ack\n");
 407                         synquacer_i2c_stop(i2c, -EAGAIN);
 408                         goto out;
 409                 }
 410
 411                 if (!is_msgend(i2c)) {
 412                         writeb(i2c->msg->buf[i2c->msg_ptr++],
 413                                i2c->base + SYNQUACER_I2C_REG_DAR);
 414
 415                         /* clear IRQ, and continue */
 416                         writeb(SYNQUACER_I2C_BCR_BEIE |
 417                                SYNQUACER_I2C_BCR_MSS |
 418                                SYNQUACER_I2C_BCR_INTE,
 419                                i2c->base + SYNQUACER_I2C_REG_BCR);
 420                         break;
 421                 }
 422                 if (is_lastmsg(i2c)) {
 423                         synquacer_i2c_stop(i2c, 0);
 424                         break;
 425                 }
 426                 dev_dbg(i2c->dev, "WRITE: Next Message\n");
 427
 428                 i2c->msg_ptr = 0;
 429                 i2c->msg_idx++;
 430                 i2c->msg++;
 431
 432                 /* send the new start */
 433                 ret = synquacer_i2c_master_start(i2c, i2c->msg);
 434                 if (ret < 0) {
 435                         dev_dbg(i2c->dev, "restart error (%d)\n", ret);
 436                         synquacer_i2c_stop(i2c, -EAGAIN);
 437                         break;
 438                 }
 439                 i2c->state = STATE_START;
 440                 break;
 441
 442         case STATE_READ:
 443                 byte = readb(i2c->base + SYNQUACER_I2C_REG_DAR);
 444                 if (!(bsr & SYNQUACER_I2C_BSR_FBT)) /* data */
 445                         i2c->msg->buf[i2c->msg_ptr++] = byte;
 446                 else /* address */
 447                         dev_dbg(i2c->dev, "address:0x%02x. ignore it.\n", byte);
 448
 449 prepare_read:
 450                 if (is_msglast(i2c)) {
 451                         writeb(SYNQUACER_I2C_BCR_MSS |
 452                                SYNQUACER_I2C_BCR_BEIE |
 453                                SYNQUACER_I2C_BCR_INTE,
 454                                i2c->base + SYNQUACER_I2C_REG_BCR);
 455                         break;
 456                 }
 457                 if (!is_msgend(i2c)) {
 458                         writeb(SYNQUACER_I2C_BCR_MSS |
 459                                SYNQUACER_I2C_BCR_BEIE |
 460                                SYNQUACER_I2C_BCR_INTE |
 461                                SYNQUACER_I2C_BCR_ACK,
 462                                i2c->base + SYNQUACER_I2C_REG_BCR);
 463                         break;
 464                 }
 465                 if (is_lastmsg(i2c)) {
 466                         /* last message, send stop and complete */
 467                         dev_dbg(i2c->dev, "READ: Send Stop\n");
 468                         synquacer_i2c_stop(i2c, 0);
 469                         break;
 470                 }
 471                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 472
 473                 i2c->msg_ptr = 0;
 474                 i2c->msg_idx++;
 475                 i2c->msg++;
 476
 477                 ret = synquacer_i2c_master_start(i2c, i2c->msg);
 478                 if (ret < 0) {
 479                         dev_dbg(i2c->dev, "restart error (%d)\n", ret);
 480                         synquacer_i2c_stop(i2c, -EAGAIN);
 481                 } else {
 482                         i2c->state = STATE_START;
 483                 }
 484                 break;
 485         default:
 486                 dev_err(i2c->dev, "called in err STATE (%d)\n", i2c->state);
 487                 break;
 488         }
 489
 490 out:
 491         WAIT_PCLK(10, i2c->pclkrate);
 492         return IRQ_HANDLED;
 493 }
 494
 495 static int synquacer_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 496                               int num)
 497 {
 498         struct synquacer_i2c *i2c;
 499         int retry;
 500         int ret;
 501
 502         i2c = i2c_get_adapdata(adap);
 503         i2c->timeout_ms = calc_timeout_ms(i2c, msgs, num);
 504
 505         dev_dbg(i2c->dev, "calculated timeout %d ms\n", i2c->timeout_ms);
 506
 507         for (retry = 0; retry <= adap->retries; retry++) {
 508                 ret = synquacer_i2c_doxfer(i2c, msgs, num);
 509                 if (ret != -EAGAIN)
 510                         return ret;
 511
 512                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 513
 514                 synquacer_i2c_hw_reset(i2c);
 515         }
 516         return -EIO;
 517 }
 518
 519 static u32 synquacer_i2c_functionality(struct i2c_adapter *adap)
 520 {
 521         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 522 }
 523
 524 static const struct i2c_algorithm synquacer_i2c_algo = {
 525         .master_xfer    = synquacer_i2c_xfer,
 526         .functionality  = synquacer_i2c_functionality,
 527 };
 528
 529 static struct i2c_adapter synquacer_i2c_ops = {
 530         .owner          = THIS_MODULE,
 531         .name           = "synquacer_i2c-adapter",
 532         .algo           = &synquacer_i2c_algo,
 533         .retries        = 5,
 534 };
 535
 536 static int synquacer_i2c_probe(struct platform_device *pdev)
 537 {
 538         struct synquacer_i2c *i2c;
 539         struct resource *r;
 540         u32 bus_speed;
 541         int ret;
 542
 543         i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
 544         if (!i2c)
 545                 return -ENOMEM;
 546
 547         bus_speed = i2c_acpi_find_bus_speed(&pdev->dev);
 548         if (!bus_speed)
 549                 device_property_read_u32(&pdev->dev, "clock-frequency",
 550                                          &bus_speed);
 551
 552         device_property_read_u32(&pdev->dev, "socionext,pclk-rate",
 553                                  &i2c->pclkrate);
 554
 555         i2c->pclk = devm_clk_get(&pdev->dev, "pclk");
 556         if (IS_ERR(i2c->pclk) && PTR_ERR(i2c->pclk) == -EPROBE_DEFER)
 557                 return -EPROBE_DEFER;
 558         if (!IS_ERR_OR_NULL(i2c->pclk)) {
 559                 dev_dbg(&pdev->dev, "clock source %p\n", i2c->pclk);
 560
 561                 ret = clk_prepare_enable(i2c->pclk);
 562                 if (ret) {
 563                         dev_err(&pdev->dev, "failed to enable clock (%d)\n",
 564                                 ret);
 565                         return ret;
 566                 }
 567                 i2c->pclkrate = clk_get_rate(i2c->pclk);
 568         }
 569
 570         if (i2c->pclkrate < SYNQUACER_I2C_MIN_CLK_RATE ||
 571             i2c->pclkrate > SYNQUACER_I2C_MAX_CLK_RATE) {
 572                 dev_err(&pdev->dev, "PCLK missing or out of range (%d)\n",
 573                         i2c->pclkrate);
 574                 return -EINVAL;
 575         }
 576
 577         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 578         i2c->base = devm_ioremap_resource(&pdev->dev, r);
 579         if (IS_ERR(i2c->base))
 580                 return PTR_ERR(i2c->base);
 581
 582         i2c->irq = platform_get_irq(pdev, 0);
 583         if (i2c->irq < 0) {
 584                 dev_err(&pdev->dev, "no IRQ resource found\n");
 585                 return -ENODEV;
 586         }
 587
 588         ret = devm_request_irq(&pdev->dev, i2c->irq, synquacer_i2c_isr,
 589                                0, dev_name(&pdev->dev), i2c);
 590         if (ret < 0) {
 591                 dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
 592                 return ret;
 593         }
 594
 595         i2c->state = STATE_IDLE;
 596         i2c->dev = &pdev->dev;
 597         i2c->adapter = synquacer_i2c_ops;
 598         i2c_set_adapdata(&i2c->adapter, i2c);
 599         i2c->adapter.dev.parent = &pdev->dev;
 600         i2c->adapter.dev.of_node = pdev->dev.of_node;
 601         ACPI_COMPANION_SET(&i2c->adapter.dev, ACPI_COMPANION(&pdev->dev));
 602         i2c->adapter.nr = pdev->id;
 603         init_completion(&i2c->completion);
 604
 605         if (bus_speed < 400000)
 606                 i2c->speed_khz = SYNQUACER_I2C_SPEED_SM;
 607         else
 608                 i2c->speed_khz = SYNQUACER_I2C_SPEED_FM;
 609
 610         synquacer_i2c_hw_init(i2c);
 611
 612         ret = i2c_add_numbered_adapter(&i2c->adapter);
 613         if (ret) {
 614                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
 615                 return ret;
 616         }
 617
 618         platform_set_drvdata(pdev, i2c);
 619
 620         dev_info(&pdev->dev, "%s: synquacer_i2c adapter\n",
 621                  dev_name(&i2c->adapter.dev));
 622
 623         return 0;
 624 }
 625
 626 static int synquacer_i2c_remove(struct platform_device *pdev)
 627 {
 628         struct synquacer_i2c *i2c = platform_get_drvdata(pdev);
 629
 630         i2c_del_adapter(&i2c->adapter);
 631         if (!IS_ERR(i2c->pclk))
 632                 clk_disable_unprepare(i2c->pclk);
 633
 634         return 0;
 635 };
 636
 637 static const struct of_device_id synquacer_i2c_dt_ids[] = {
 638         { .compatible = "socionext,synquacer-i2c" },
 639         { /* sentinel */ }
 640 };
 641 MODULE_DEVICE_TABLE(of, synquacer_i2c_dt_ids);
 642
 643 #ifdef CONFIG_ACPI
 644 static const struct acpi_device_id synquacer_i2c_acpi_ids[] = {
 645         { "SCX0003" },
 646         { /* sentinel */ }
 647 };
 648 MODULE_DEVICE_TABLE(acpi, synquacer_i2c_acpi_ids);
 649 #endif
 650
 651 static struct platform_driver synquacer_i2c_driver = {
 652         .probe  = synquacer_i2c_probe,
 653         .remove = synquacer_i2c_remove,
 654         .driver = {
 655                 .name = "synquacer_i2c",
 656                 .of_match_table = of_match_ptr(synquacer_i2c_dt_ids),
 657                 .acpi_match_table = ACPI_PTR(synquacer_i2c_acpi_ids),
 658         },
 659 };
 660 module_platform_driver(synquacer_i2c_driver);
 661
 662 MODULE_AUTHOR("Fujitsu Semiconductor Ltd");
 663 MODULE_DESCRIPTION("Socionext SynQuacer I2C Driver");
 664 MODULE_LICENSE("GPL v2");