drivers/i2c/busses/i2c-sh_mobile.c

   1 /*
   2  * SuperH Mobile I2C Controller
   3  *
   4  * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
   5  *
   6  * Copyright (C) 2008 Magnus Damm
   7  *
   8  * Portions of the code based on out-of-tree driver i2c-sh7343.c
   9  * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  */
  20
  21 #include <linux/clk.h>
  22 #include <linux/delay.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/dma-mapping.h>
  25 #include <linux/err.h>
  26 #include <linux/i2c.h>
  27 #include <linux/i2c/i2c-sh_mobile.h>
  28 #include <linux/init.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/io.h>
  31 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33 #include <linux/of_device.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/pm_runtime.h>
  36 #include <linux/slab.h>
  37
  38 /* Transmit operation:                                                      */
  39 /*                                                                          */
  40 /* 0 byte transmit                                                          */
  41 /* BUS:     S     A8     ACK   P(*)                                         */
  42 /* IRQ:       DTE   WAIT                                                    */
  43 /* ICIC:                                                                    */
  44 /* ICCR: 0x94 0x90                                                          */
  45 /* ICDR:      A8                                                            */
  46 /*                                                                          */
  47 /* 1 byte transmit                                                          */
  48 /* BUS:     S     A8     ACK   D8(1)   ACK   P(*)                           */
  49 /* IRQ:       DTE   WAIT         WAIT                                       */
  50 /* ICIC:      -DTE                                                          */
  51 /* ICCR: 0x94       0x90                                                    */
  52 /* ICDR:      A8    D8(1)                                                   */
  53 /*                                                                          */
  54 /* 2 byte transmit                                                          */
  55 /* BUS:     S     A8     ACK   D8(1)   ACK   D8(2)   ACK   P(*)             */
  56 /* IRQ:       DTE   WAIT         WAIT          WAIT                         */
  57 /* ICIC:      -DTE                                                          */
  58 /* ICCR: 0x94                    0x90                                       */
  59 /* ICDR:      A8    D8(1)        D8(2)                                      */
  60 /*                                                                          */
  61 /* 3 bytes or more, +---------+ gets repeated                               */
  62 /*                                                                          */
  63 /*                                                                          */
  64 /* Receive operation:                                                       */
  65 /*                                                                          */
  66 /* 0 byte receive - not supported since slave may hold SDA low              */
  67 /*                                                                          */
  68 /* 1 byte receive       [TX] | [RX]                                         */
  69 /* BUS:     S     A8     ACK | D8(1)   ACK   P(*)                           */
  70 /* IRQ:       DTE   WAIT     |   WAIT     DTE                               */
  71 /* ICIC:      -DTE           |   +DTE                                       */
  72 /* ICCR: 0x94       0x81     |   0xc0                                       */
  73 /* ICDR:      A8             |            D8(1)                             */
  74 /*                                                                          */
  75 /* 2 byte receive        [TX]| [RX]                                         */
  76 /* BUS:     S     A8     ACK | D8(1)   ACK   D8(2)   ACK   P(*)             */
  77 /* IRQ:       DTE   WAIT     |   WAIT          WAIT     DTE                 */
  78 /* ICIC:      -DTE           |                 +DTE                         */
  79 /* ICCR: 0x94       0x81     |                 0xc0                         */
  80 /* ICDR:      A8             |                 D8(1)    D8(2)               */
  81 /*                                                                          */
  82 /* 3 byte receive       [TX] | [RX]                                     (*) */
  83 /* BUS:     S     A8     ACK | D8(1)   ACK   D8(2)   ACK   D8(3)   ACK    P */
  84 /* IRQ:       DTE   WAIT     |   WAIT          WAIT         WAIT      DTE   */
  85 /* ICIC:      -DTE           |                              +DTE            */
  86 /* ICCR: 0x94       0x81     |                              0xc0            */
  87 /* ICDR:      A8             |                 D8(1)        D8(2)     D8(3) */
  88 /*                                                                          */
  89 /* 4 bytes or more, this part is repeated    +---------+                    */
  90 /*                                                                          */
  91 /*                                                                          */
  92 /* Interrupt order and BUSY flag                                            */
  93 /*     ___                                                 _                */
  94 /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/                 */
  95 /* SCL      \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/                   */
  96 /*                                                                          */
  97 /*        S   D7  D6  D5  D4  D3  D2  D1  D0              P(*)              */
  98 /*                                           ___                            */
  99 /* WAIT IRQ ________________________________/   \___________                */
 100 /* TACK IRQ ____________________________________/   \_______                */
 101 /* DTE  IRQ __________________________________________/   \_                */
 102 /* AL   IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX                */
 103 /*         _______________________________________________                  */
 104 /* BUSY __/                                               \_                */
 105 /*                                                                          */
 106 /* (*) The STOP condition is only sent by the master at the end of the last */
 107 /* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */
 108 /* only cleared after the STOP condition, so, between messages we have to   */
 109 /* poll for the DTE bit.                                                    */
 110 /*                                                                          */
 111
 112 enum sh_mobile_i2c_op {
 113         OP_START = 0,
 114         OP_TX_FIRST,
 115         OP_TX,
 116         OP_TX_STOP,
 117         OP_TX_STOP_DATA,
 118         OP_TX_TO_RX,
 119         OP_RX,
 120         OP_RX_STOP,
 121         OP_RX_STOP_DATA,
 122 };
 123
 124 struct sh_mobile_i2c_data {
 125         struct device *dev;
 126         void __iomem *reg;
 127         struct i2c_adapter adap;
 128         unsigned long bus_speed;
 129         unsigned int clks_per_count;
 130         struct clk *clk;
 131         u_int8_t icic;
 132         u_int8_t flags;
 133         u_int16_t iccl;
 134         u_int16_t icch;
 135
 136         spinlock_t lock;
 137         wait_queue_head_t wait;
 138         struct i2c_msg *msg;
 139         int pos;
 140         int sr;
 141         bool send_stop;
 142
 143         struct resource *res;
 144         struct dma_chan *dma_tx;
 145         struct dma_chan *dma_rx;
 146         struct scatterlist sg;
 147         enum dma_data_direction dma_direction;
 148 };
 149
 150 struct sh_mobile_dt_config {
 151         int clks_per_count;
 152 };
 153
 154 #define IIC_FLAG_HAS_ICIC67     (1 << 0)
 155
 156 #define STANDARD_MODE           100000
 157 #define FAST_MODE               400000
 158
 159 /* Register offsets */
 160 #define ICDR                    0x00
 161 #define ICCR                    0x04
 162 #define ICSR                    0x08
 163 #define ICIC                    0x0c
 164 #define ICCL                    0x10
 165 #define ICCH                    0x14
 166
 167 /* Register bits */
 168 #define ICCR_ICE                0x80
 169 #define ICCR_RACK               0x40
 170 #define ICCR_TRS                0x10
 171 #define ICCR_BBSY               0x04
 172 #define ICCR_SCP                0x01
 173
 174 #define ICSR_SCLM               0x80
 175 #define ICSR_SDAM               0x40
 176 #define SW_DONE                 0x20
 177 #define ICSR_BUSY               0x10
 178 #define ICSR_AL                 0x08
 179 #define ICSR_TACK               0x04
 180 #define ICSR_WAIT               0x02
 181 #define ICSR_DTE                0x01
 182
 183 #define ICIC_ICCLB8             0x80
 184 #define ICIC_ICCHB8             0x40
 185 #define ICIC_TDMAE              0x20
 186 #define ICIC_RDMAE              0x10
 187 #define ICIC_ALE                0x08
 188 #define ICIC_TACKE              0x04
 189 #define ICIC_WAITE              0x02
 190 #define ICIC_DTEE               0x01
 191
 192 static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
 193 {
 194         if (offs == ICIC)
 195                 data |= pd->icic;
 196
 197         iowrite8(data, pd->reg + offs);
 198 }
 199
 200 static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
 201 {
 202         return ioread8(pd->reg + offs);
 203 }
 204
 205 static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
 206                         unsigned char set, unsigned char clr)
 207 {
 208         iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr);
 209 }
 210
 211 static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf)
 212 {
 213         /*
 214          * Conditional expression:
 215          *   ICCL >= COUNT_CLK * (tLOW + tf)
 216          *
 217          * SH-Mobile IIC hardware starts counting the LOW period of
 218          * the SCL signal (tLOW) as soon as it pulls the SCL line.
 219          * In order to meet the tLOW timing spec, we need to take into
 220          * account the fall time of SCL signal (tf).  Default tf value
 221          * should be 0.3 us, for safety.
 222          */
 223         return (((count_khz * (tLOW + tf)) + 5000) / 10000);
 224 }
 225
 226 static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf)
 227 {
 228         /*
 229          * Conditional expression:
 230          *   ICCH >= COUNT_CLK * (tHIGH + tf)
 231          *
 232          * SH-Mobile IIC hardware is aware of SCL transition period 'tr',
 233          * and can ignore it.  SH-Mobile IIC controller starts counting
 234          * the HIGH period of the SCL signal (tHIGH) after the SCL input
 235          * voltage increases at VIH.
 236          *
 237          * Afterward it turned out calculating ICCH using only tHIGH spec
 238          * will result in violation of the tHD;STA timing spec.  We need
 239          * to take into account the fall time of SDA signal (tf) at START
 240          * condition, in order to meet both tHIGH and tHD;STA specs.
 241          */
 242         return (((count_khz * (tHIGH + tf)) + 5000) / 10000);
 243 }
 244
 245 static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
 246 {
 247         unsigned long i2c_clk_khz;
 248         u32 tHIGH, tLOW, tf;
 249         uint16_t max_val;
 250
 251         /* Get clock rate after clock is enabled */
 252         clk_prepare_enable(pd->clk);
 253         i2c_clk_khz = clk_get_rate(pd->clk) / 1000;
 254         clk_disable_unprepare(pd->clk);
 255         i2c_clk_khz /= pd->clks_per_count;
 256
 257         if (pd->bus_speed == STANDARD_MODE) {
 258                 tLOW    = 47;   /* tLOW = 4.7 us */
 259                 tHIGH   = 40;   /* tHD;STA = tHIGH = 4.0 us */
 260                 tf      = 3;    /* tf = 0.3 us */
 261         } else if (pd->bus_speed == FAST_MODE) {
 262                 tLOW    = 13;   /* tLOW = 1.3 us */
 263                 tHIGH   = 6;    /* tHD;STA = tHIGH = 0.6 us */
 264                 tf      = 3;    /* tf = 0.3 us */
 265         } else {
 266                 dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
 267                         pd->bus_speed);
 268                 return -EINVAL;
 269         }
 270
 271         pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf);
 272         pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
 273
 274         max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
 275         if (pd->iccl > max_val || pd->icch > max_val) {
 276                 dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n",
 277                         pd->iccl, pd->icch);
 278                 return -EINVAL;
 279         }
 280
 281         /* one more bit of ICCL in ICIC */
 282         if (pd->iccl & 0x100)
 283                 pd->icic |= ICIC_ICCLB8;
 284         else
 285                 pd->icic &= ~ICIC_ICCLB8;
 286
 287         /* one more bit of ICCH in ICIC */
 288         if (pd->icch & 0x100)
 289                 pd->icic |= ICIC_ICCHB8;
 290         else
 291                 pd->icic &= ~ICIC_ICCHB8;
 292
 293         dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch);
 294         return 0;
 295 }
 296
 297 static void activate_ch(struct sh_mobile_i2c_data *pd)
 298 {
 299         /* Wake up device and enable clock */
 300         pm_runtime_get_sync(pd->dev);
 301         clk_prepare_enable(pd->clk);
 302
 303         /* Enable channel and configure rx ack */
 304         iic_set_clr(pd, ICCR, ICCR_ICE, 0);
 305
 306         /* Mask all interrupts */
 307         iic_wr(pd, ICIC, 0);
 308
 309         /* Set the clock */
 310         iic_wr(pd, ICCL, pd->iccl & 0xff);
 311         iic_wr(pd, ICCH, pd->icch & 0xff);
 312 }
 313
 314 static void deactivate_ch(struct sh_mobile_i2c_data *pd)
 315 {
 316         /* Clear/disable interrupts */
 317         iic_wr(pd, ICSR, 0);
 318         iic_wr(pd, ICIC, 0);
 319
 320         /* Disable channel */
 321         iic_set_clr(pd, ICCR, 0, ICCR_ICE);
 322
 323         /* Disable clock and mark device as idle */
 324         clk_disable_unprepare(pd->clk);
 325         pm_runtime_put_sync(pd->dev);
 326 }
 327
 328 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
 329                             enum sh_mobile_i2c_op op, unsigned char data)
 330 {
 331         unsigned char ret = 0;
 332         unsigned long flags;
 333
 334         dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
 335
 336         spin_lock_irqsave(&pd->lock, flags);
 337
 338         switch (op) {
 339         case OP_START: /* issue start and trigger DTE interrupt */
 340                 iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY);
 341                 break;
 342         case OP_TX_FIRST: /* disable DTE interrupt and write data */
 343                 iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
 344                 iic_wr(pd, ICDR, data);
 345                 break;
 346         case OP_TX: /* write data */
 347                 iic_wr(pd, ICDR, data);
 348                 break;
 349         case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */
 350                 iic_wr(pd, ICDR, data);
 351                 /* fallthrough */
 352         case OP_TX_STOP: /* issue a stop */
 353                 iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS
 354                                                : ICCR_ICE | ICCR_TRS | ICCR_BBSY);
 355                 break;
 356         case OP_TX_TO_RX: /* select read mode */
 357                 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
 358                 break;
 359         case OP_RX: /* just read data */
 360                 ret = iic_rd(pd, ICDR);
 361                 break;
 362         case OP_RX_STOP: /* enable DTE interrupt, issue stop */
 363                 iic_wr(pd, ICIC,
 364                        ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
 365                 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
 366                 break;
 367         case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
 368                 iic_wr(pd, ICIC,
 369                        ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
 370                 ret = iic_rd(pd, ICDR);
 371                 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
 372                 break;
 373         }
 374
 375         spin_unlock_irqrestore(&pd->lock, flags);
 376
 377         dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
 378         return ret;
 379 }
 380
 381 static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
 382 {
 383         return pd->pos == -1;
 384 }
 385
 386 static bool sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
 387 {
 388         return pd->pos == pd->msg->len - 1;
 389 }
 390
 391 static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
 392                                    unsigned char *buf)
 393 {
 394         switch (pd->pos) {
 395         case -1:
 396                 *buf = (pd->msg->addr & 0x7f) << 1;
 397                 *buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
 398                 break;
 399         default:
 400                 *buf = pd->msg->buf[pd->pos];
 401         }
 402 }
 403
 404 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
 405 {
 406         unsigned char data;
 407
 408         if (pd->pos == pd->msg->len) {
 409                 /* Send stop if we haven't yet (DMA case) */
 410                 if (pd->send_stop && (iic_rd(pd, ICCR) & ICCR_BBSY))
 411                         i2c_op(pd, OP_TX_STOP, 0);
 412                 return 1;
 413         }
 414
 415         sh_mobile_i2c_get_data(pd, &data);
 416
 417         if (sh_mobile_i2c_is_last_byte(pd))
 418                 i2c_op(pd, OP_TX_STOP_DATA, data);
 419         else if (sh_mobile_i2c_is_first_byte(pd))
 420                 i2c_op(pd, OP_TX_FIRST, data);
 421         else
 422                 i2c_op(pd, OP_TX, data);
 423
 424         pd->pos++;
 425         return 0;
 426 }
 427
 428 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
 429 {
 430         unsigned char data;
 431         int real_pos;
 432
 433         do {
 434                 if (pd->pos <= -1) {
 435                         sh_mobile_i2c_get_data(pd, &data);
 436
 437                         if (sh_mobile_i2c_is_first_byte(pd))
 438                                 i2c_op(pd, OP_TX_FIRST, data);
 439                         else
 440                                 i2c_op(pd, OP_TX, data);
 441                         break;
 442                 }
 443
 444                 if (pd->pos == 0) {
 445                         i2c_op(pd, OP_TX_TO_RX, 0);
 446                         break;
 447                 }
 448
 449                 real_pos = pd->pos - 2;
 450
 451                 if (pd->pos == pd->msg->len) {
 452                         if (real_pos < 0) {
 453                                 i2c_op(pd, OP_RX_STOP, 0);
 454                                 break;
 455                         }
 456                         data = i2c_op(pd, OP_RX_STOP_DATA, 0);
 457                 } else
 458                         data = i2c_op(pd, OP_RX, 0);
 459
 460                 if (real_pos >= 0)
 461                         pd->msg->buf[real_pos] = data;
 462         } while (0);
 463
 464         pd->pos++;
 465         return pd->pos == (pd->msg->len + 2);
 466 }
 467
 468 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
 469 {
 470         struct sh_mobile_i2c_data *pd = dev_id;
 471         unsigned char sr;
 472         int wakeup = 0;
 473
 474         sr = iic_rd(pd, ICSR);
 475         pd->sr |= sr; /* remember state */
 476
 477         dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
 478                (pd->msg->flags & I2C_M_RD) ? "read" : "write",
 479                pd->pos, pd->msg->len);
 480
 481         /* Kick off TxDMA after preface was done */
 482         if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
 483                 iic_set_clr(pd, ICIC, ICIC_TDMAE, 0);
 484         else if (sr & (ICSR_AL | ICSR_TACK))
 485                 /* don't interrupt transaction - continue to issue stop */
 486                 iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
 487         else if (pd->msg->flags & I2C_M_RD)
 488                 wakeup = sh_mobile_i2c_isr_rx(pd);
 489         else
 490                 wakeup = sh_mobile_i2c_isr_tx(pd);
 491
 492         /* Kick off RxDMA after preface was done */
 493         if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
 494                 iic_set_clr(pd, ICIC, ICIC_RDMAE, 0);
 495
 496         if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
 497                 iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
 498
 499         if (wakeup) {
 500                 pd->sr |= SW_DONE;
 501                 wake_up(&pd->wait);
 502         }
 503
 504         /* defeat write posting to avoid spurious WAIT interrupts */
 505         iic_rd(pd, ICSR);
 506
 507         return IRQ_HANDLED;
 508 }
 509
 510 static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd)
 511 {
 512         struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE
 513                                 ? pd->dma_rx : pd->dma_tx;
 514
 515         dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg),
 516                          pd->msg->len, pd->dma_direction);
 517
 518         pd->dma_direction = DMA_NONE;
 519 }
 520
 521 static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd)
 522 {
 523         if (pd->dma_direction == DMA_NONE)
 524                 return;
 525         else if (pd->dma_direction == DMA_FROM_DEVICE)
 526                 dmaengine_terminate_all(pd->dma_rx);
 527         else if (pd->dma_direction == DMA_TO_DEVICE)
 528                 dmaengine_terminate_all(pd->dma_tx);
 529
 530         sh_mobile_i2c_dma_unmap(pd);
 531 }
 532
 533 static void sh_mobile_i2c_dma_callback(void *data)
 534 {
 535         struct sh_mobile_i2c_data *pd = data;
 536
 537         sh_mobile_i2c_dma_unmap(pd);
 538         pd->pos = pd->msg->len;
 539
 540         iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
 541 }
 542
 543 static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev,
 544                                 enum dma_transfer_direction dir, dma_addr_t port_addr)
 545 {
 546         struct dma_chan *chan;
 547         struct dma_slave_config cfg;
 548         char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
 549         int ret;
 550
 551         chan = dma_request_slave_channel_reason(dev, chan_name);
 552         if (IS_ERR(chan)) {
 553                 ret = PTR_ERR(chan);
 554                 dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret);
 555                 return chan;
 556         }
 557
 558         memset(&cfg, 0, sizeof(cfg));
 559         cfg.direction = dir;
 560         if (dir == DMA_MEM_TO_DEV) {
 561                 cfg.dst_addr = port_addr;
 562                 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 563         } else {
 564                 cfg.src_addr = port_addr;
 565                 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 566         }
 567
 568         ret = dmaengine_slave_config(chan, &cfg);
 569         if (ret) {
 570                 dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
 571                 dma_release_channel(chan);
 572                 return ERR_PTR(ret);
 573         }
 574
 575         dev_dbg(dev, "got DMA channel for %s\n", chan_name);
 576         return chan;
 577 }
 578
 579 static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
 580 {
 581         bool read = pd->msg->flags & I2C_M_RD;
 582         enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 583         struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
 584         struct dma_async_tx_descriptor *txdesc;
 585         dma_addr_t dma_addr;
 586         dma_cookie_t cookie;
 587
 588         if (PTR_ERR(chan) == -EPROBE_DEFER) {
 589                 if (read)
 590                         chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
 591                                                                            pd->res->start + ICDR);
 592                 else
 593                         chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
 594                                                                            pd->res->start + ICDR);
 595         }
 596
 597         if (IS_ERR(chan))
 598                 return;
 599
 600         dma_addr = dma_map_single(chan->device->dev, pd->msg->buf, pd->msg->len, dir);
 601         if (dma_mapping_error(pd->dev, dma_addr)) {
 602                 dev_dbg(pd->dev, "dma map failed, using PIO\n");
 603                 return;
 604         }
 605
 606         sg_dma_len(&pd->sg) = pd->msg->len;
 607         sg_dma_address(&pd->sg) = dma_addr;
 608
 609         pd->dma_direction = dir;
 610
 611         txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1,
 612                                          read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
 613                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 614         if (!txdesc) {
 615                 dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
 616                 sh_mobile_i2c_cleanup_dma(pd);
 617                 return;
 618         }
 619
 620         txdesc->callback = sh_mobile_i2c_dma_callback;
 621         txdesc->callback_param = pd;
 622
 623         cookie = dmaengine_submit(txdesc);
 624         if (dma_submit_error(cookie)) {
 625                 dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
 626                 sh_mobile_i2c_cleanup_dma(pd);
 627                 return;
 628         }
 629
 630         dma_async_issue_pending(chan);
 631 }
 632
 633 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
 634                     bool do_init)
 635 {
 636         if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
 637                 dev_err(pd->dev, "Unsupported zero length i2c read\n");
 638                 return -EOPNOTSUPP;
 639         }
 640
 641         if (do_init) {
 642                 /* Initialize channel registers */
 643                 iic_set_clr(pd, ICCR, 0, ICCR_ICE);
 644
 645                 /* Enable channel and configure rx ack */
 646                 iic_set_clr(pd, ICCR, ICCR_ICE, 0);
 647
 648                 /* Set the clock */
 649                 iic_wr(pd, ICCL, pd->iccl & 0xff);
 650                 iic_wr(pd, ICCH, pd->icch & 0xff);
 651         }
 652
 653         pd->msg = usr_msg;
 654         pd->pos = -1;
 655         pd->sr = 0;
 656
 657         if (pd->msg->len > 8)
 658                 sh_mobile_i2c_xfer_dma(pd);
 659
 660         /* Enable all interrupts to begin with */
 661         iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
 662         return 0;
 663 }
 664
 665 static int poll_dte(struct sh_mobile_i2c_data *pd)
 666 {
 667         int i;
 668
 669         for (i = 1000; i; i--) {
 670                 u_int8_t val = iic_rd(pd, ICSR);
 671
 672                 if (val & ICSR_DTE)
 673                         break;
 674
 675                 if (val & ICSR_TACK)
 676                         return -ENXIO;
 677
 678                 udelay(10);
 679         }
 680
 681         return i ? 0 : -ETIMEDOUT;
 682 }
 683
 684 static int poll_busy(struct sh_mobile_i2c_data *pd)
 685 {
 686         int i;
 687
 688         for (i = 1000; i; i--) {
 689                 u_int8_t val = iic_rd(pd, ICSR);
 690
 691                 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
 692
 693                 /* the interrupt handler may wake us up before the
 694                  * transfer is finished, so poll the hardware
 695                  * until we're done.
 696                  */
 697                 if (!(val & ICSR_BUSY)) {
 698                         /* handle missing acknowledge and arbitration lost */
 699                         val |= pd->sr;
 700                         if (val & ICSR_TACK)
 701                                 return -ENXIO;
 702                         if (val & ICSR_AL)
 703                                 return -EAGAIN;
 704                         break;
 705                 }
 706
 707                 udelay(10);
 708         }
 709
 710         return i ? 0 : -ETIMEDOUT;
 711 }
 712
 713 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
 714                               struct i2c_msg *msgs,
 715                               int num)
 716 {
 717         struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
 718         struct i2c_msg  *msg;
 719         int err = 0;
 720         int i, k;
 721
 722         activate_ch(pd);
 723
 724         /* Process all messages */
 725         for (i = 0; i < num; i++) {
 726                 bool do_start = pd->send_stop || !i;
 727                 msg = &msgs[i];
 728                 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
 729
 730                 err = start_ch(pd, msg, do_start);
 731                 if (err)
 732                         break;
 733
 734                 if (do_start)
 735                         i2c_op(pd, OP_START, 0);
 736
 737                 /* The interrupt handler takes care of the rest... */
 738                 k = wait_event_timeout(pd->wait,
 739                                        pd->sr & (ICSR_TACK | SW_DONE),
 740                                        5 * HZ);
 741                 if (!k) {
 742                         dev_err(pd->dev, "Transfer request timed out\n");
 743                         if (pd->dma_direction != DMA_NONE)
 744                                 sh_mobile_i2c_cleanup_dma(pd);
 745
 746                         err = -ETIMEDOUT;
 747                         break;
 748                 }
 749
 750                 if (pd->send_stop)
 751                         err = poll_busy(pd);
 752                 else
 753                         err = poll_dte(pd);
 754                 if (err < 0)
 755                         break;
 756         }
 757
 758         deactivate_ch(pd);
 759
 760         if (!err)
 761                 err = num;
 762         return err;
 763 }
 764
 765 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
 766 {
 767         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 768 }
 769
 770 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
 771         .functionality  = sh_mobile_i2c_func,
 772         .master_xfer    = sh_mobile_i2c_xfer,
 773 };
 774
 775 static const struct sh_mobile_dt_config default_dt_config = {
 776         .clks_per_count = 1,
 777 };
 778
 779 static const struct sh_mobile_dt_config fast_clock_dt_config = {
 780         .clks_per_count = 2,
 781 };
 782
 783 static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
 784         { .compatible = "renesas,rmobile-iic", .data = &default_dt_config },
 785         { .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config },
 786         { .compatible = "renesas,iic-r8a7790", .data = &fast_clock_dt_config },
 787         { .compatible = "renesas,iic-r8a7791", .data = &fast_clock_dt_config },
 788         { .compatible = "renesas,iic-r8a7792", .data = &fast_clock_dt_config },
 789         { .compatible = "renesas,iic-r8a7793", .data = &fast_clock_dt_config },
 790         { .compatible = "renesas,iic-r8a7794", .data = &fast_clock_dt_config },
 791         { .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config },
 792         {},
 793 };
 794 MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
 795
 796 static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
 797 {
 798         if (!IS_ERR(pd->dma_tx)) {
 799                 dma_release_channel(pd->dma_tx);
 800                 pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
 801         }
 802
 803         if (!IS_ERR(pd->dma_rx)) {
 804                 dma_release_channel(pd->dma_rx);
 805                 pd->dma_rx = ERR_PTR(-EPROBE_DEFER);
 806         }
 807 }
 808
 809 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd)
 810 {
 811         struct resource *res;
 812         resource_size_t n;
 813         int k = 0, ret;
 814
 815         while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
 816                 for (n = res->start; n <= res->end; n++) {
 817                         ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr,
 818                                           0, dev_name(&dev->dev), pd);
 819                         if (ret) {
 820                                 dev_err(&dev->dev, "cannot request IRQ %pa\n", &n);
 821                                 return ret;
 822                         }
 823                 }
 824                 k++;
 825         }
 826
 827         return k > 0 ? 0 : -ENOENT;
 828 }
 829
 830 static int sh_mobile_i2c_probe(struct platform_device *dev)
 831 {
 832         struct i2c_sh_mobile_platform_data *pdata = dev_get_platdata(&dev->dev);
 833         struct sh_mobile_i2c_data *pd;
 834         struct i2c_adapter *adap;
 835         struct resource *res;
 836         int ret;
 837         u32 bus_speed;
 838
 839         pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
 840         if (!pd)
 841                 return -ENOMEM;
 842
 843         pd->clk = devm_clk_get(&dev->dev, NULL);
 844         if (IS_ERR(pd->clk)) {
 845                 dev_err(&dev->dev, "cannot get clock\n");
 846                 return PTR_ERR(pd->clk);
 847         }
 848
 849         ret = sh_mobile_i2c_hook_irqs(dev, pd);
 850         if (ret)
 851                 return ret;
 852
 853         pd->dev = &dev->dev;
 854         platform_set_drvdata(dev, pd);
 855
 856         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 857
 858         pd->res = res;
 859         pd->reg = devm_ioremap_resource(&dev->dev, res);
 860         if (IS_ERR(pd->reg))
 861                 return PTR_ERR(pd->reg);
 862
 863         /* Use platform data bus speed or STANDARD_MODE */
 864         ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed);
 865         pd->bus_speed = ret ? STANDARD_MODE : bus_speed;
 866
 867         pd->clks_per_count = 1;
 868
 869         if (dev->dev.of_node) {
 870                 const struct of_device_id *match;
 871
 872                 match = of_match_device(sh_mobile_i2c_dt_ids, &dev->dev);
 873                 if (match) {
 874                         const struct sh_mobile_dt_config *config;
 875
 876                         config = match->data;
 877                         pd->clks_per_count = config->clks_per_count;
 878                 }
 879         } else {
 880                 if (pdata && pdata->bus_speed)
 881                         pd->bus_speed = pdata->bus_speed;
 882                 if (pdata && pdata->clks_per_count)
 883                         pd->clks_per_count = pdata->clks_per_count;
 884         }
 885
 886         /* The IIC blocks on SH-Mobile ARM processors
 887          * come with two new bits in ICIC.
 888          */
 889         if (resource_size(res) > 0x17)
 890                 pd->flags |= IIC_FLAG_HAS_ICIC67;
 891
 892         ret = sh_mobile_i2c_init(pd);
 893         if (ret)
 894                 return ret;
 895
 896         /* Init DMA */
 897         sg_init_table(&pd->sg, 1);
 898         pd->dma_direction = DMA_NONE;
 899         pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
 900
 901         /* Enable Runtime PM for this device.
 902          *
 903          * Also tell the Runtime PM core to ignore children
 904          * for this device since it is valid for us to suspend
 905          * this I2C master driver even though the slave devices
 906          * on the I2C bus may not be suspended.
 907          *
 908          * The state of the I2C hardware bus is unaffected by
 909          * the Runtime PM state.
 910          */
 911         pm_suspend_ignore_children(&dev->dev, true);
 912         pm_runtime_enable(&dev->dev);
 913
 914         /* setup the private data */
 915         adap = &pd->adap;
 916         i2c_set_adapdata(adap, pd);
 917
 918         adap->owner = THIS_MODULE;
 919         adap->algo = &sh_mobile_i2c_algorithm;
 920         adap->dev.parent = &dev->dev;
 921         adap->retries = 5;
 922         adap->nr = dev->id;
 923         adap->dev.of_node = dev->dev.of_node;
 924
 925         strlcpy(adap->name, dev->name, sizeof(adap->name));
 926
 927         spin_lock_init(&pd->lock);
 928         init_waitqueue_head(&pd->wait);
 929
 930         ret = i2c_add_numbered_adapter(adap);
 931         if (ret < 0) {
 932                 sh_mobile_i2c_release_dma(pd);
 933                 dev_err(&dev->dev, "cannot add numbered adapter\n");
 934                 return ret;
 935         }
 936
 937         dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed);
 938
 939         return 0;
 940 }
 941
 942 static int sh_mobile_i2c_remove(struct platform_device *dev)
 943 {
 944         struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
 945
 946         i2c_del_adapter(&pd->adap);
 947         sh_mobile_i2c_release_dma(pd);
 948         pm_runtime_disable(&dev->dev);
 949         return 0;
 950 }
 951
 952 static int sh_mobile_i2c_runtime_nop(struct device *dev)
 953 {
 954         /* Runtime PM callback shared between ->runtime_suspend()
 955          * and ->runtime_resume(). Simply returns success.
 956          *
 957          * This driver re-initializes all registers after
 958          * pm_runtime_get_sync() anyway so there is no need
 959          * to save and restore registers here.
 960          */
 961         return 0;
 962 }
 963
 964 static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
 965         .runtime_suspend = sh_mobile_i2c_runtime_nop,
 966         .runtime_resume = sh_mobile_i2c_runtime_nop,
 967 };
 968
 969 static struct platform_driver sh_mobile_i2c_driver = {
 970         .driver         = {
 971                 .name           = "i2c-sh_mobile",
 972                 .pm             = &sh_mobile_i2c_dev_pm_ops,
 973                 .of_match_table = sh_mobile_i2c_dt_ids,
 974         },
 975         .probe          = sh_mobile_i2c_probe,
 976         .remove         = sh_mobile_i2c_remove,
 977 };
 978
 979 static int __init sh_mobile_i2c_adap_init(void)
 980 {
 981         return platform_driver_register(&sh_mobile_i2c_driver);
 982 }
 983 subsys_initcall(sh_mobile_i2c_adap_init);
 984
 985 static void __exit sh_mobile_i2c_adap_exit(void)
 986 {
 987         platform_driver_unregister(&sh_mobile_i2c_driver);
 988 }
 989 module_exit(sh_mobile_i2c_adap_exit);
 990
 991 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
 992 MODULE_AUTHOR("Magnus Damm and Wolfram Sang");
 993 MODULE_LICENSE("GPL v2");
 994 MODULE_ALIAS("platform:i2c-sh_mobile");