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

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This source file includes following definitions.
uniphier_fi2c_fill_txfifo
uniphier_fi2c_drain_rxfifo
uniphier_fi2c_set_irqs
uniphier_fi2c_clear_irqs
uniphier_fi2c_stop
uniphier_fi2c_interrupt
uniphier_fi2c_tx_init
uniphier_fi2c_rx_init
uniphier_fi2c_reset
uniphier_fi2c_prepare_operation
uniphier_fi2c_recover
uniphier_fi2c_master_xfer_one
uniphier_fi2c_check_bus_busy
uniphier_fi2c_master_xfer
uniphier_fi2c_functionality
uniphier_fi2c_get_scl
uniphier_fi2c_set_scl
uniphier_fi2c_get_sda
uniphier_fi2c_unprepare_recovery
uniphier_fi2c_hw_init
uniphier_fi2c_probe
uniphier_fi2c_remove
uniphier_fi2c_suspend
uniphier_fi2c_resume
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
   4  */
   5 
   6 #include <linux/clk.h>
   7 #include <linux/i2c.h>
   8 #include <linux/iopoll.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/io.h>
  11 #include <linux/module.h>
  12 #include <linux/platform_device.h>
  13 
  14 #define UNIPHIER_FI2C_CR        0x00    /* control register */
  15 #define     UNIPHIER_FI2C_CR_MST        BIT(3)  /* master mode */
  16 #define     UNIPHIER_FI2C_CR_STA        BIT(2)  /* start condition */
  17 #define     UNIPHIER_FI2C_CR_STO        BIT(1)  /* stop condition */
  18 #define     UNIPHIER_FI2C_CR_NACK       BIT(0)  /* do not return ACK */
  19 #define UNIPHIER_FI2C_DTTX      0x04    /* TX FIFO */
  20 #define     UNIPHIER_FI2C_DTTX_CMD      BIT(8)  /* send command (slave addr) */
  21 #define     UNIPHIER_FI2C_DTTX_RD       BIT(0)  /* read transaction */
  22 #define UNIPHIER_FI2C_DTRX      0x04    /* RX FIFO */
  23 #define UNIPHIER_FI2C_SLAD      0x0c    /* slave address */
  24 #define UNIPHIER_FI2C_CYC       0x10    /* clock cycle control */
  25 #define UNIPHIER_FI2C_LCTL      0x14    /* clock low period control */
  26 #define UNIPHIER_FI2C_SSUT      0x18    /* restart/stop setup time control */
  27 #define UNIPHIER_FI2C_DSUT      0x1c    /* data setup time control */
  28 #define UNIPHIER_FI2C_INT       0x20    /* interrupt status */
  29 #define UNIPHIER_FI2C_IE        0x24    /* interrupt enable */
  30 #define UNIPHIER_FI2C_IC        0x28    /* interrupt clear */
  31 #define     UNIPHIER_FI2C_INT_TE        BIT(9)  /* TX FIFO empty */
  32 #define     UNIPHIER_FI2C_INT_RF        BIT(8)  /* RX FIFO full */
  33 #define     UNIPHIER_FI2C_INT_TC        BIT(7)  /* send complete (STOP) */
  34 #define     UNIPHIER_FI2C_INT_RC        BIT(6)  /* receive complete (STOP) */
  35 #define     UNIPHIER_FI2C_INT_TB        BIT(5)  /* sent specified bytes */
  36 #define     UNIPHIER_FI2C_INT_RB        BIT(4)  /* received specified bytes */
  37 #define     UNIPHIER_FI2C_INT_NA        BIT(2)  /* no ACK */
  38 #define     UNIPHIER_FI2C_INT_AL        BIT(1)  /* arbitration lost */
  39 #define UNIPHIER_FI2C_SR        0x2c    /* status register */
  40 #define     UNIPHIER_FI2C_SR_DB         BIT(12) /* device busy */
  41 #define     UNIPHIER_FI2C_SR_STS        BIT(11) /* stop condition detected */
  42 #define     UNIPHIER_FI2C_SR_BB         BIT(8)  /* bus busy */
  43 #define     UNIPHIER_FI2C_SR_RFF        BIT(3)  /* RX FIFO full */
  44 #define     UNIPHIER_FI2C_SR_RNE        BIT(2)  /* RX FIFO not empty */
  45 #define     UNIPHIER_FI2C_SR_TNF        BIT(1)  /* TX FIFO not full */
  46 #define     UNIPHIER_FI2C_SR_TFE        BIT(0)  /* TX FIFO empty */
  47 #define UNIPHIER_FI2C_RST       0x34    /* reset control */
  48 #define     UNIPHIER_FI2C_RST_TBRST     BIT(2)  /* clear TX FIFO */
  49 #define     UNIPHIER_FI2C_RST_RBRST     BIT(1)  /* clear RX FIFO */
  50 #define     UNIPHIER_FI2C_RST_RST       BIT(0)  /* forcible bus reset */
  51 #define UNIPHIER_FI2C_BM        0x38    /* bus monitor */
  52 #define     UNIPHIER_FI2C_BM_SDAO       BIT(3)  /* output for SDA line */
  53 #define     UNIPHIER_FI2C_BM_SDAS       BIT(2)  /* readback of SDA line */
  54 #define     UNIPHIER_FI2C_BM_SCLO       BIT(1)  /* output for SCL line */
  55 #define     UNIPHIER_FI2C_BM_SCLS       BIT(0)  /* readback of SCL line */
  56 #define UNIPHIER_FI2C_NOISE     0x3c    /* noise filter control */
  57 #define UNIPHIER_FI2C_TBC       0x40    /* TX byte count setting */
  58 #define UNIPHIER_FI2C_RBC       0x44    /* RX byte count setting */
  59 #define UNIPHIER_FI2C_TBCM      0x48    /* TX byte count monitor */
  60 #define UNIPHIER_FI2C_RBCM      0x4c    /* RX byte count monitor */
  61 #define UNIPHIER_FI2C_BRST      0x50    /* bus reset */
  62 #define     UNIPHIER_FI2C_BRST_FOEN     BIT(1)  /* normal operation */
  63 #define     UNIPHIER_FI2C_BRST_RSCL     BIT(0)  /* release SCL */
  64 
  65 #define UNIPHIER_FI2C_INT_FAULTS        \
  66                                 (UNIPHIER_FI2C_INT_NA | UNIPHIER_FI2C_INT_AL)
  67 #define UNIPHIER_FI2C_INT_STOP          \
  68                                 (UNIPHIER_FI2C_INT_TC | UNIPHIER_FI2C_INT_RC)
  69 
  70 #define UNIPHIER_FI2C_RD                BIT(0)
  71 #define UNIPHIER_FI2C_STOP              BIT(1)
  72 #define UNIPHIER_FI2C_MANUAL_NACK       BIT(2)
  73 #define UNIPHIER_FI2C_BYTE_WISE         BIT(3)
  74 #define UNIPHIER_FI2C_DEFER_STOP_COMP   BIT(4)
  75 
  76 #define UNIPHIER_FI2C_DEFAULT_SPEED     100000
  77 #define UNIPHIER_FI2C_MAX_SPEED         400000
  78 #define UNIPHIER_FI2C_FIFO_SIZE         8
  79 
  80 struct uniphier_fi2c_priv {
  81         struct completion comp;
  82         struct i2c_adapter adap;
  83         void __iomem *membase;
  84         struct clk *clk;
  85         unsigned int len;
  86         u8 *buf;
  87         u32 enabled_irqs;
  88         int error;
  89         unsigned int flags;
  90         unsigned int busy_cnt;
  91         unsigned int clk_cycle;
  92         spinlock_t lock;        /* IRQ synchronization */
  93 };
  94 
  95 static void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv,
  96                                       bool first)
  97 {
  98         int fifo_space = UNIPHIER_FI2C_FIFO_SIZE;
  99 
 100         /*
 101          * TX-FIFO stores slave address in it for the first access.
 102          * Decrement the counter.
 103          */
 104         if (first)
 105                 fifo_space--;
 106 
 107         while (priv->len) {
 108                 if (fifo_space-- <= 0)
 109                         break;
 110 
 111                 writel(*priv->buf++, priv->membase + UNIPHIER_FI2C_DTTX);
 112                 priv->len--;
 113         }
 114 }
 115 
 116 static void uniphier_fi2c_drain_rxfifo(struct uniphier_fi2c_priv *priv)
 117 {
 118         int fifo_left = priv->flags & UNIPHIER_FI2C_BYTE_WISE ?
 119                                                 1 : UNIPHIER_FI2C_FIFO_SIZE;
 120 
 121         while (priv->len) {
 122                 if (fifo_left-- <= 0)
 123                         break;
 124 
 125                 *priv->buf++ = readl(priv->membase + UNIPHIER_FI2C_DTRX);
 126                 priv->len--;
 127         }
 128 }
 129 
 130 static void uniphier_fi2c_set_irqs(struct uniphier_fi2c_priv *priv)
 131 {
 132         writel(priv->enabled_irqs, priv->membase + UNIPHIER_FI2C_IE);
 133 }
 134 
 135 static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv,
 136                                      u32 mask)
 137 {
 138         writel(mask, priv->membase + UNIPHIER_FI2C_IC);
 139 }
 140 
 141 static void uniphier_fi2c_stop(struct uniphier_fi2c_priv *priv)
 142 {
 143         priv->enabled_irqs |= UNIPHIER_FI2C_INT_STOP;
 144         uniphier_fi2c_set_irqs(priv);
 145         writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STO,
 146                priv->membase + UNIPHIER_FI2C_CR);
 147 }
 148 
 149 static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
 150 {
 151         struct uniphier_fi2c_priv *priv = dev_id;
 152         u32 irq_status;
 153 
 154         spin_lock(&priv->lock);
 155 
 156         irq_status = readl(priv->membase + UNIPHIER_FI2C_INT);
 157         irq_status &= priv->enabled_irqs;
 158 
 159         if (irq_status & UNIPHIER_FI2C_INT_STOP)
 160                 goto complete;
 161 
 162         if (unlikely(irq_status & UNIPHIER_FI2C_INT_AL)) {
 163                 priv->error = -EAGAIN;
 164                 goto complete;
 165         }
 166 
 167         if (unlikely(irq_status & UNIPHIER_FI2C_INT_NA)) {
 168                 priv->error = -ENXIO;
 169                 if (priv->flags & UNIPHIER_FI2C_RD) {
 170                         /*
 171                          * work around a hardware bug:
 172                          * The receive-completed interrupt is never set even if
 173                          * STOP condition is detected after the address phase
 174                          * of read transaction fails to get ACK.
 175                          * To avoid time-out error, we issue STOP here,
 176                          * but do not wait for its completion.
 177                          * It should be checked after exiting this handler.
 178                          */
 179                         uniphier_fi2c_stop(priv);
 180                         priv->flags |= UNIPHIER_FI2C_DEFER_STOP_COMP;
 181                         goto complete;
 182                 }
 183                 goto stop;
 184         }
 185 
 186         if (irq_status & UNIPHIER_FI2C_INT_TE) {
 187                 if (!priv->len)
 188                         goto data_done;
 189 
 190                 uniphier_fi2c_fill_txfifo(priv, false);
 191                 goto handled;
 192         }
 193 
 194         if (irq_status & (UNIPHIER_FI2C_INT_RF | UNIPHIER_FI2C_INT_RB)) {
 195                 uniphier_fi2c_drain_rxfifo(priv);
 196                 /*
 197                  * If the number of bytes to read is multiple of the FIFO size
 198                  * (msg->len == 8, 16, 24, ...), the INT_RF bit is set a little
 199                  * earlier than INT_RB. We wait for INT_RB to confirm the
 200                  * completion of the current message.
 201                  */
 202                 if (!priv->len && (irq_status & UNIPHIER_FI2C_INT_RB))
 203                         goto data_done;
 204 
 205                 if (unlikely(priv->flags & UNIPHIER_FI2C_MANUAL_NACK)) {
 206                         if (priv->len <= UNIPHIER_FI2C_FIFO_SIZE &&
 207                             !(priv->flags & UNIPHIER_FI2C_BYTE_WISE)) {
 208                                 priv->enabled_irqs |= UNIPHIER_FI2C_INT_RB;
 209                                 uniphier_fi2c_set_irqs(priv);
 210                                 priv->flags |= UNIPHIER_FI2C_BYTE_WISE;
 211                         }
 212                         if (priv->len <= 1)
 213                                 writel(UNIPHIER_FI2C_CR_MST |
 214                                        UNIPHIER_FI2C_CR_NACK,
 215                                        priv->membase + UNIPHIER_FI2C_CR);
 216                 }
 217 
 218                 goto handled;
 219         }
 220 
 221         spin_unlock(&priv->lock);
 222 
 223         return IRQ_NONE;
 224 
 225 data_done:
 226         if (priv->flags & UNIPHIER_FI2C_STOP) {
 227 stop:
 228                 uniphier_fi2c_stop(priv);
 229         } else {
 230 complete:
 231                 priv->enabled_irqs = 0;
 232                 uniphier_fi2c_set_irqs(priv);
 233                 complete(&priv->comp);
 234         }
 235 
 236 handled:
 237         /*
 238          * This controller makes a pause while any bit of the IRQ status is
 239          * asserted. Clear the asserted bit to kick the controller just before
 240          * exiting the handler.
 241          */
 242         uniphier_fi2c_clear_irqs(priv, irq_status);
 243 
 244         spin_unlock(&priv->lock);
 245 
 246         return IRQ_HANDLED;
 247 }
 248 
 249 static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr,
 250                                   bool repeat)
 251 {
 252         priv->enabled_irqs |= UNIPHIER_FI2C_INT_TE;
 253         uniphier_fi2c_set_irqs(priv);
 254 
 255         /* do not use TX byte counter */
 256         writel(0, priv->membase + UNIPHIER_FI2C_TBC);
 257         /* set slave address */
 258         writel(UNIPHIER_FI2C_DTTX_CMD | addr << 1,
 259                priv->membase + UNIPHIER_FI2C_DTTX);
 260         /*
 261          * First chunk of data. For a repeated START condition, do not write
 262          * data to the TX fifo here to avoid the timing issue.
 263          */
 264         if (!repeat)
 265                 uniphier_fi2c_fill_txfifo(priv, true);
 266 }
 267 
 268 static void uniphier_fi2c_rx_init(struct uniphier_fi2c_priv *priv, u16 addr)
 269 {
 270         priv->flags |= UNIPHIER_FI2C_RD;
 271 
 272         if (likely(priv->len < 256)) {
 273                 /*
 274                  * If possible, use RX byte counter.
 275                  * It can automatically handle NACK for the last byte.
 276                  */
 277                 writel(priv->len, priv->membase + UNIPHIER_FI2C_RBC);
 278                 priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF |
 279                                       UNIPHIER_FI2C_INT_RB;
 280         } else {
 281                 /*
 282                  * The byte counter can not count over 256.  In this case,
 283                  * do not use it at all.  Drain data when FIFO gets full,
 284                  * but treat the last portion as a special case.
 285                  */
 286                 writel(0, priv->membase + UNIPHIER_FI2C_RBC);
 287                 priv->flags |= UNIPHIER_FI2C_MANUAL_NACK;
 288                 priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF;
 289         }
 290 
 291         uniphier_fi2c_set_irqs(priv);
 292 
 293         /* set slave address with RD bit */
 294         writel(UNIPHIER_FI2C_DTTX_CMD | UNIPHIER_FI2C_DTTX_RD | addr << 1,
 295                priv->membase + UNIPHIER_FI2C_DTTX);
 296 }
 297 
 298 static void uniphier_fi2c_reset(struct uniphier_fi2c_priv *priv)
 299 {
 300         writel(UNIPHIER_FI2C_RST_RST, priv->membase + UNIPHIER_FI2C_RST);
 301 }
 302 
 303 static void uniphier_fi2c_prepare_operation(struct uniphier_fi2c_priv *priv)
 304 {
 305         writel(UNIPHIER_FI2C_BRST_FOEN | UNIPHIER_FI2C_BRST_RSCL,
 306                priv->membase + UNIPHIER_FI2C_BRST);
 307 }
 308 
 309 static void uniphier_fi2c_recover(struct uniphier_fi2c_priv *priv)
 310 {
 311         uniphier_fi2c_reset(priv);
 312         i2c_recover_bus(&priv->adap);
 313 }
 314 
 315 static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
 316                                          struct i2c_msg *msg, bool repeat,
 317                                          bool stop)
 318 {
 319         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 320         bool is_read = msg->flags & I2C_M_RD;
 321         unsigned long time_left, flags;
 322 
 323         priv->len = msg->len;
 324         priv->buf = msg->buf;
 325         priv->enabled_irqs = UNIPHIER_FI2C_INT_FAULTS;
 326         priv->error = 0;
 327         priv->flags = 0;
 328 
 329         if (stop)
 330                 priv->flags |= UNIPHIER_FI2C_STOP;
 331 
 332         reinit_completion(&priv->comp);
 333         uniphier_fi2c_clear_irqs(priv, U32_MAX);
 334         writel(UNIPHIER_FI2C_RST_TBRST | UNIPHIER_FI2C_RST_RBRST,
 335                priv->membase + UNIPHIER_FI2C_RST);      /* reset TX/RX FIFO */
 336 
 337         spin_lock_irqsave(&priv->lock, flags);
 338 
 339         if (is_read)
 340                 uniphier_fi2c_rx_init(priv, msg->addr);
 341         else
 342                 uniphier_fi2c_tx_init(priv, msg->addr, repeat);
 343 
 344         /*
 345          * For a repeated START condition, writing a slave address to the FIFO
 346          * kicks the controller. So, the UNIPHIER_FI2C_CR register should be
 347          * written only for a non-repeated START condition.
 348          */
 349         if (!repeat)
 350                 writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
 351                        priv->membase + UNIPHIER_FI2C_CR);
 352 
 353         spin_unlock_irqrestore(&priv->lock, flags);
 354 
 355         time_left = wait_for_completion_timeout(&priv->comp, adap->timeout);
 356 
 357         spin_lock_irqsave(&priv->lock, flags);
 358         priv->enabled_irqs = 0;
 359         uniphier_fi2c_set_irqs(priv);
 360         spin_unlock_irqrestore(&priv->lock, flags);
 361 
 362         if (!time_left) {
 363                 dev_err(&adap->dev, "transaction timeout.\n");
 364                 uniphier_fi2c_recover(priv);
 365                 return -ETIMEDOUT;
 366         }
 367 
 368         if (unlikely(priv->flags & UNIPHIER_FI2C_DEFER_STOP_COMP)) {
 369                 u32 status;
 370                 int ret;
 371 
 372                 ret = readl_poll_timeout(priv->membase + UNIPHIER_FI2C_SR,
 373                                          status,
 374                                          (status & UNIPHIER_FI2C_SR_STS) &&
 375                                          !(status & UNIPHIER_FI2C_SR_BB),
 376                                          1, 20);
 377                 if (ret) {
 378                         dev_err(&adap->dev,
 379                                 "stop condition was not completed.\n");
 380                         uniphier_fi2c_recover(priv);
 381                         return ret;
 382                 }
 383         }
 384 
 385         return priv->error;
 386 }
 387 
 388 static int uniphier_fi2c_check_bus_busy(struct i2c_adapter *adap)
 389 {
 390         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 391 
 392         if (readl(priv->membase + UNIPHIER_FI2C_SR) & UNIPHIER_FI2C_SR_DB) {
 393                 if (priv->busy_cnt++ > 3) {
 394                         /*
 395                          * If bus busy continues too long, it is probably
 396                          * in a wrong state.  Try bus recovery.
 397                          */
 398                         uniphier_fi2c_recover(priv);
 399                         priv->busy_cnt = 0;
 400                 }
 401 
 402                 return -EAGAIN;
 403         }
 404 
 405         priv->busy_cnt = 0;
 406         return 0;
 407 }
 408 
 409 static int uniphier_fi2c_master_xfer(struct i2c_adapter *adap,
 410                                      struct i2c_msg *msgs, int num)
 411 {
 412         struct i2c_msg *msg, *emsg = msgs + num;
 413         bool repeat = false;
 414         int ret;
 415 
 416         ret = uniphier_fi2c_check_bus_busy(adap);
 417         if (ret)
 418                 return ret;
 419 
 420         for (msg = msgs; msg < emsg; msg++) {
 421                 /* Emit STOP if it is the last message or I2C_M_STOP is set. */
 422                 bool stop = (msg + 1 == emsg) || (msg->flags & I2C_M_STOP);
 423 
 424                 ret = uniphier_fi2c_master_xfer_one(adap, msg, repeat, stop);
 425                 if (ret)
 426                         return ret;
 427 
 428                 repeat = !stop;
 429         }
 430 
 431         return num;
 432 }
 433 
 434 static u32 uniphier_fi2c_functionality(struct i2c_adapter *adap)
 435 {
 436         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 437 }
 438 
 439 static const struct i2c_algorithm uniphier_fi2c_algo = {
 440         .master_xfer = uniphier_fi2c_master_xfer,
 441         .functionality = uniphier_fi2c_functionality,
 442 };
 443 
 444 static int uniphier_fi2c_get_scl(struct i2c_adapter *adap)
 445 {
 446         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 447 
 448         return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
 449                                                         UNIPHIER_FI2C_BM_SCLS);
 450 }
 451 
 452 static void uniphier_fi2c_set_scl(struct i2c_adapter *adap, int val)
 453 {
 454         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 455 
 456         writel(val ? UNIPHIER_FI2C_BRST_RSCL : 0,
 457                priv->membase + UNIPHIER_FI2C_BRST);
 458 }
 459 
 460 static int uniphier_fi2c_get_sda(struct i2c_adapter *adap)
 461 {
 462         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 463 
 464         return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
 465                                                         UNIPHIER_FI2C_BM_SDAS);
 466 }
 467 
 468 static void uniphier_fi2c_unprepare_recovery(struct i2c_adapter *adap)
 469 {
 470         uniphier_fi2c_prepare_operation(i2c_get_adapdata(adap));
 471 }
 472 
 473 static struct i2c_bus_recovery_info uniphier_fi2c_bus_recovery_info = {
 474         .recover_bus = i2c_generic_scl_recovery,
 475         .get_scl = uniphier_fi2c_get_scl,
 476         .set_scl = uniphier_fi2c_set_scl,
 477         .get_sda = uniphier_fi2c_get_sda,
 478         .unprepare_recovery = uniphier_fi2c_unprepare_recovery,
 479 };
 480 
 481 static void uniphier_fi2c_hw_init(struct uniphier_fi2c_priv *priv)
 482 {
 483         unsigned int cyc = priv->clk_cycle;
 484         u32 tmp;
 485 
 486         tmp = readl(priv->membase + UNIPHIER_FI2C_CR);
 487         tmp |= UNIPHIER_FI2C_CR_MST;
 488         writel(tmp, priv->membase + UNIPHIER_FI2C_CR);
 489 
 490         uniphier_fi2c_reset(priv);
 491 
 492         /*
 493          *  Standard-mode: tLOW + tHIGH = 10 us
 494          *  Fast-mode:     tLOW + tHIGH = 2.5 us
 495          */
 496         writel(cyc, priv->membase + UNIPHIER_FI2C_CYC);
 497         /*
 498          *  Standard-mode: tLOW = 4.7 us, tHIGH = 4.0 us, tBUF = 4.7 us
 499          *  Fast-mode:     tLOW = 1.3 us, tHIGH = 0.6 us, tBUF = 1.3 us
 500          * "tLow/tHIGH = 5/4" meets both.
 501          */
 502         writel(cyc * 5 / 9, priv->membase + UNIPHIER_FI2C_LCTL);
 503         /*
 504          *  Standard-mode: tHD;STA = 4.0 us, tSU;STA = 4.7 us, tSU;STO = 4.0 us
 505          *  Fast-mode:     tHD;STA = 0.6 us, tSU;STA = 0.6 us, tSU;STO = 0.6 us
 506          */
 507         writel(cyc / 2, priv->membase + UNIPHIER_FI2C_SSUT);
 508         /*
 509          *  Standard-mode: tSU;DAT = 250 ns
 510          *  Fast-mode:     tSU;DAT = 100 ns
 511          */
 512         writel(cyc / 16, priv->membase + UNIPHIER_FI2C_DSUT);
 513 
 514         uniphier_fi2c_prepare_operation(priv);
 515 }
 516 
 517 static int uniphier_fi2c_probe(struct platform_device *pdev)
 518 {
 519         struct device *dev = &pdev->dev;
 520         struct uniphier_fi2c_priv *priv;
 521         u32 bus_speed;
 522         unsigned long clk_rate;
 523         int irq, ret;
 524 
 525         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 526         if (!priv)
 527                 return -ENOMEM;
 528 
 529         priv->membase = devm_platform_ioremap_resource(pdev, 0);
 530         if (IS_ERR(priv->membase))
 531                 return PTR_ERR(priv->membase);
 532 
 533         irq = platform_get_irq(pdev, 0);
 534         if (irq < 0) {
 535                 dev_err(dev, "failed to get IRQ number\n");
 536                 return irq;
 537         }
 538 
 539         if (of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed))
 540                 bus_speed = UNIPHIER_FI2C_DEFAULT_SPEED;
 541 
 542         if (!bus_speed || bus_speed > UNIPHIER_FI2C_MAX_SPEED) {
 543                 dev_err(dev, "invalid clock-frequency %d\n", bus_speed);
 544                 return -EINVAL;
 545         }
 546 
 547         priv->clk = devm_clk_get(dev, NULL);
 548         if (IS_ERR(priv->clk)) {
 549                 dev_err(dev, "failed to get clock\n");
 550                 return PTR_ERR(priv->clk);
 551         }
 552 
 553         ret = clk_prepare_enable(priv->clk);
 554         if (ret)
 555                 return ret;
 556 
 557         clk_rate = clk_get_rate(priv->clk);
 558         if (!clk_rate) {
 559                 dev_err(dev, "input clock rate should not be zero\n");
 560                 ret = -EINVAL;
 561                 goto disable_clk;
 562         }
 563 
 564         priv->clk_cycle = clk_rate / bus_speed;
 565         init_completion(&priv->comp);
 566         spin_lock_init(&priv->lock);
 567         priv->adap.owner = THIS_MODULE;
 568         priv->adap.algo = &uniphier_fi2c_algo;
 569         priv->adap.dev.parent = dev;
 570         priv->adap.dev.of_node = dev->of_node;
 571         strlcpy(priv->adap.name, "UniPhier FI2C", sizeof(priv->adap.name));
 572         priv->adap.bus_recovery_info = &uniphier_fi2c_bus_recovery_info;
 573         i2c_set_adapdata(&priv->adap, priv);
 574         platform_set_drvdata(pdev, priv);
 575 
 576         uniphier_fi2c_hw_init(priv);
 577 
 578         ret = devm_request_irq(dev, irq, uniphier_fi2c_interrupt, 0,
 579                                pdev->name, priv);
 580         if (ret) {
 581                 dev_err(dev, "failed to request irq %d\n", irq);
 582                 goto disable_clk;
 583         }
 584 
 585         ret = i2c_add_adapter(&priv->adap);
 586 disable_clk:
 587         if (ret)
 588                 clk_disable_unprepare(priv->clk);
 589 
 590         return ret;
 591 }
 592 
 593 static int uniphier_fi2c_remove(struct platform_device *pdev)
 594 {
 595         struct uniphier_fi2c_priv *priv = platform_get_drvdata(pdev);
 596 
 597         i2c_del_adapter(&priv->adap);
 598         clk_disable_unprepare(priv->clk);
 599 
 600         return 0;
 601 }
 602 
 603 static int __maybe_unused uniphier_fi2c_suspend(struct device *dev)
 604 {
 605         struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
 606 
 607         clk_disable_unprepare(priv->clk);
 608 
 609         return 0;
 610 }
 611 
 612 static int __maybe_unused uniphier_fi2c_resume(struct device *dev)
 613 {
 614         struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
 615         int ret;
 616 
 617         ret = clk_prepare_enable(priv->clk);
 618         if (ret)
 619                 return ret;
 620 
 621         uniphier_fi2c_hw_init(priv);
 622 
 623         return 0;
 624 }
 625 
 626 static const struct dev_pm_ops uniphier_fi2c_pm_ops = {
 627         SET_SYSTEM_SLEEP_PM_OPS(uniphier_fi2c_suspend, uniphier_fi2c_resume)
 628 };
 629 
 630 static const struct of_device_id uniphier_fi2c_match[] = {
 631         { .compatible = "socionext,uniphier-fi2c" },
 632         { /* sentinel */ }
 633 };
 634 MODULE_DEVICE_TABLE(of, uniphier_fi2c_match);
 635 
 636 static struct platform_driver uniphier_fi2c_drv = {
 637         .probe  = uniphier_fi2c_probe,
 638         .remove = uniphier_fi2c_remove,
 639         .driver = {
 640                 .name  = "uniphier-fi2c",
 641                 .of_match_table = uniphier_fi2c_match,
 642                 .pm = &uniphier_fi2c_pm_ops,
 643         },
 644 };
 645 module_platform_driver(uniphier_fi2c_drv);
 646 
 647 MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
 648 MODULE_DESCRIPTION("UniPhier FIFO-builtin I2C bus driver");
 649 MODULE_LICENSE("GPL");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/i2c/busses/i2c-uniphier-f.c

DEFINITIONS
