drivers/i2c/exynos_hs_i2c.c

   1 /*
   2  * Copyright (c) 2016, Google Inc
   3  *
   4  * (C) Copyright 2002
   5  * David Mueller, ELSOFT AG, d.mueller@elsoft.ch
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9
  10 #include <common.h>
  11 #include <dm.h>
  12 #include <i2c.h>
  13 #include <asm/arch/clk.h>
  14 #include <asm/arch/cpu.h>
  15 #include <asm/arch/pinmux.h>
  16 #include "s3c24x0_i2c.h"
  17
  18 DECLARE_GLOBAL_DATA_PTR;
  19
  20 /* HSI2C-specific register description */
  21
  22 /* I2C_CTL Register bits */
  23 #define HSI2C_FUNC_MODE_I2C             (1u << 0)
  24 #define HSI2C_MASTER                    (1u << 3)
  25 #define HSI2C_RXCHON                    (1u << 6)       /* Write/Send */
  26 #define HSI2C_TXCHON                    (1u << 7)       /* Read/Receive */
  27 #define HSI2C_SW_RST                    (1u << 31)
  28
  29 /* I2C_FIFO_CTL Register bits */
  30 #define HSI2C_RXFIFO_EN                 (1u << 0)
  31 #define HSI2C_TXFIFO_EN                 (1u << 1)
  32 #define HSI2C_TXFIFO_TRIGGER_LEVEL      (0x20 << 16)
  33 #define HSI2C_RXFIFO_TRIGGER_LEVEL      (0x20 << 4)
  34
  35 /* I2C_TRAILING_CTL Register bits */
  36 #define HSI2C_TRAILING_COUNT            (0xff)
  37
  38 /* I2C_INT_EN Register bits */
  39 #define HSI2C_TX_UNDERRUN_EN            (1u << 2)
  40 #define HSI2C_TX_OVERRUN_EN             (1u << 3)
  41 #define HSI2C_RX_UNDERRUN_EN            (1u << 4)
  42 #define HSI2C_RX_OVERRUN_EN             (1u << 5)
  43 #define HSI2C_INT_TRAILING_EN           (1u << 6)
  44 #define HSI2C_INT_I2C_EN                (1u << 9)
  45
  46 #define HSI2C_INT_ERROR_MASK    (HSI2C_TX_UNDERRUN_EN |\
  47                                  HSI2C_TX_OVERRUN_EN  |\
  48                                  HSI2C_RX_UNDERRUN_EN |\
  49                                  HSI2C_RX_OVERRUN_EN  |\
  50                                  HSI2C_INT_TRAILING_EN)
  51
  52 /* I2C_CONF Register bits */
  53 #define HSI2C_AUTO_MODE                 (1u << 31)
  54 #define HSI2C_10BIT_ADDR_MODE           (1u << 30)
  55 #define HSI2C_HS_MODE                   (1u << 29)
  56
  57 /* I2C_AUTO_CONF Register bits */
  58 #define HSI2C_READ_WRITE                (1u << 16)
  59 #define HSI2C_STOP_AFTER_TRANS          (1u << 17)
  60 #define HSI2C_MASTER_RUN                (1u << 31)
  61
  62 /* I2C_TIMEOUT Register bits */
  63 #define HSI2C_TIMEOUT_EN                (1u << 31)
  64
  65 /* I2C_TRANS_STATUS register bits */
  66 #define HSI2C_MASTER_BUSY               (1u << 17)
  67 #define HSI2C_SLAVE_BUSY                (1u << 16)
  68 #define HSI2C_TIMEOUT_AUTO              (1u << 4)
  69 #define HSI2C_NO_DEV                    (1u << 3)
  70 #define HSI2C_NO_DEV_ACK                (1u << 2)
  71 #define HSI2C_TRANS_ABORT               (1u << 1)
  72 #define HSI2C_TRANS_SUCCESS             (1u << 0)
  73 #define HSI2C_TRANS_ERROR_MASK  (HSI2C_TIMEOUT_AUTO |\
  74                                  HSI2C_NO_DEV | HSI2C_NO_DEV_ACK |\
  75                                  HSI2C_TRANS_ABORT)
  76 #define HSI2C_TRANS_FINISHED_MASK (HSI2C_TRANS_ERROR_MASK | HSI2C_TRANS_SUCCESS)
  77
  78
  79 /* I2C_FIFO_STAT Register bits */
  80 #define HSI2C_RX_FIFO_EMPTY             (1u << 24)
  81 #define HSI2C_RX_FIFO_FULL              (1u << 23)
  82 #define HSI2C_TX_FIFO_EMPTY             (1u << 8)
  83 #define HSI2C_TX_FIFO_FULL              (1u << 7)
  84 #define HSI2C_RX_FIFO_LEVEL(x)          (((x) >> 16) & 0x7f)
  85 #define HSI2C_TX_FIFO_LEVEL(x)          ((x) & 0x7f)
  86
  87 #define HSI2C_SLV_ADDR_MAS(x)           ((x & 0x3ff) << 10)
  88
  89 #define HSI2C_TIMEOUT_US 10000 /* 10 ms, finer granularity */
  90
  91 /*
  92  * Wait for transfer completion.
  93  *
  94  * This function reads the interrupt status register waiting for the INT_I2C
  95  * bit to be set, which indicates copletion of a transaction.
  96  *
  97  * @param i2c: pointer to the appropriate register bank
  98  *
  99  * @return: I2C_OK in case of successful completion, I2C_NOK_TIMEOUT in case
 100  *          the status bits do not get set in time, or an approrpiate error
 101  *          value in case of transfer errors.
 102  */
 103 static int hsi2c_wait_for_trx(struct exynos5_hsi2c *i2c)
 104 {
 105         int i = HSI2C_TIMEOUT_US;
 106
 107         while (i-- > 0) {
 108                 u32 int_status = readl(&i2c->usi_int_stat);
 109
 110                 if (int_status & HSI2C_INT_I2C_EN) {
 111                         u32 trans_status = readl(&i2c->usi_trans_status);
 112
 113                         /* Deassert pending interrupt. */
 114                         writel(int_status, &i2c->usi_int_stat);
 115
 116                         if (trans_status & HSI2C_NO_DEV_ACK) {
 117                                 debug("%s: no ACK from device\n", __func__);
 118                                 return I2C_NACK;
 119                         }
 120                         if (trans_status & HSI2C_NO_DEV) {
 121                                 debug("%s: no device\n", __func__);
 122                                 return I2C_NOK;
 123                         }
 124                         if (trans_status & HSI2C_TRANS_ABORT) {
 125                                 debug("%s: arbitration lost\n", __func__);
 126                                 return I2C_NOK_LA;
 127                         }
 128                         if (trans_status & HSI2C_TIMEOUT_AUTO) {
 129                                 debug("%s: device timed out\n", __func__);
 130                                 return I2C_NOK_TOUT;
 131                         }
 132                         return I2C_OK;
 133                 }
 134                 udelay(1);
 135         }
 136         debug("%s: transaction timeout!\n", __func__);
 137         return I2C_NOK_TOUT;
 138 }
 139
 140 static int hsi2c_get_clk_details(struct s3c24x0_i2c_bus *i2c_bus)
 141 {
 142         struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
 143         ulong clkin;
 144         unsigned int op_clk = i2c_bus->clock_frequency;
 145         unsigned int i = 0, utemp0 = 0, utemp1 = 0;
 146         unsigned int t_ftl_cycle;
 147
 148 #if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
 149         clkin = get_i2c_clk();
 150 #else
 151         clkin = get_PCLK();
 152 #endif
 153         /* FPCLK / FI2C =
 154          * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE
 155          * uTemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2)
 156          * uTemp1 = (TSCLK_L + TSCLK_H + 2)
 157          * uTemp2 = TSCLK_L + TSCLK_H
 158          */
 159         t_ftl_cycle = (readl(&hsregs->usi_conf) >> 16) & 0x7;
 160         utemp0 = (clkin / op_clk) - 8 - 2 * t_ftl_cycle;
 161
 162         /* CLK_DIV max is 256 */
 163         for (i = 0; i < 256; i++) {
 164                 utemp1 = utemp0 / (i + 1);
 165                 if ((utemp1 < 512) && (utemp1 > 4)) {
 166                         i2c_bus->clk_cycle = utemp1 - 2;
 167                         i2c_bus->clk_div = i;
 168                         return 0;
 169                 }
 170         }
 171         return -EINVAL;
 172 }
 173
 174 static void hsi2c_ch_init(struct s3c24x0_i2c_bus *i2c_bus)
 175 {
 176         struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
 177         unsigned int t_sr_release;
 178         unsigned int n_clkdiv;
 179         unsigned int t_start_su, t_start_hd;
 180         unsigned int t_stop_su;
 181         unsigned int t_data_su, t_data_hd;
 182         unsigned int t_scl_l, t_scl_h;
 183         u32 i2c_timing_s1;
 184         u32 i2c_timing_s2;
 185         u32 i2c_timing_s3;
 186         u32 i2c_timing_sla;
 187
 188         n_clkdiv = i2c_bus->clk_div;
 189         t_scl_l = i2c_bus->clk_cycle / 2;
 190         t_scl_h = i2c_bus->clk_cycle / 2;
 191         t_start_su = t_scl_l;
 192         t_start_hd = t_scl_l;
 193         t_stop_su = t_scl_l;
 194         t_data_su = t_scl_l / 2;
 195         t_data_hd = t_scl_l / 2;
 196         t_sr_release = i2c_bus->clk_cycle;
 197
 198         i2c_timing_s1 = t_start_su << 24 | t_start_hd << 16 | t_stop_su << 8;
 199         i2c_timing_s2 = t_data_su << 24 | t_scl_l << 8 | t_scl_h << 0;
 200         i2c_timing_s3 = n_clkdiv << 16 | t_sr_release << 0;
 201         i2c_timing_sla = t_data_hd << 0;
 202
 203         writel(HSI2C_TRAILING_COUNT, &hsregs->usi_trailing_ctl);
 204
 205         /* Clear to enable Timeout */
 206         clrsetbits_le32(&hsregs->usi_timeout, HSI2C_TIMEOUT_EN, 0);
 207
 208         /* set AUTO mode */
 209         writel(readl(&hsregs->usi_conf) | HSI2C_AUTO_MODE, &hsregs->usi_conf);
 210
 211         /* Enable completion conditions' reporting. */
 212         writel(HSI2C_INT_I2C_EN, &hsregs->usi_int_en);
 213
 214         /* Enable FIFOs */
 215         writel(HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN, &hsregs->usi_fifo_ctl);
 216
 217         /* Currently operating in Fast speed mode. */
 218         writel(i2c_timing_s1, &hsregs->usi_timing_fs1);
 219         writel(i2c_timing_s2, &hsregs->usi_timing_fs2);
 220         writel(i2c_timing_s3, &hsregs->usi_timing_fs3);
 221         writel(i2c_timing_sla, &hsregs->usi_timing_sla);
 222 }
 223
 224 /* SW reset for the high speed bus */
 225 static void exynos5_i2c_reset(struct s3c24x0_i2c_bus *i2c_bus)
 226 {
 227         struct exynos5_hsi2c *i2c = i2c_bus->hsregs;
 228         u32 i2c_ctl;
 229
 230         /* Set and clear the bit for reset */
 231         i2c_ctl = readl(&i2c->usi_ctl);
 232         i2c_ctl |= HSI2C_SW_RST;
 233         writel(i2c_ctl, &i2c->usi_ctl);
 234
 235         i2c_ctl = readl(&i2c->usi_ctl);
 236         i2c_ctl &= ~HSI2C_SW_RST;
 237         writel(i2c_ctl, &i2c->usi_ctl);
 238
 239         /* Initialize the configure registers */
 240         hsi2c_ch_init(i2c_bus);
 241 }
 242
 243 /*
 244  * Poll the appropriate bit of the fifo status register until the interface is
 245  * ready to process the next byte or timeout expires.
 246  *
 247  * In addition to the FIFO status register this function also polls the
 248  * interrupt status register to be able to detect unexpected transaction
 249  * completion.
 250  *
 251  * When FIFO is ready to process the next byte, this function returns I2C_OK.
 252  * If in course of polling the INT_I2C assertion is detected, the function
 253  * returns I2C_NOK. If timeout happens before any of the above conditions is
 254  * met - the function returns I2C_NOK_TOUT;
 255
 256  * @param i2c: pointer to the appropriate i2c register bank.
 257  * @param rx_transfer: set to True if the receive transaction is in progress.
 258  * @return: as described above.
 259  */
 260 static unsigned hsi2c_poll_fifo(struct exynos5_hsi2c *i2c, bool rx_transfer)
 261 {
 262         u32 fifo_bit = rx_transfer ? HSI2C_RX_FIFO_EMPTY : HSI2C_TX_FIFO_FULL;
 263         int i = HSI2C_TIMEOUT_US;
 264
 265         while (readl(&i2c->usi_fifo_stat) & fifo_bit) {
 266                 if (readl(&i2c->usi_int_stat) & HSI2C_INT_I2C_EN) {
 267                         /*
 268                          * There is a chance that assertion of
 269                          * HSI2C_INT_I2C_EN and deassertion of
 270                          * HSI2C_RX_FIFO_EMPTY happen simultaneously. Let's
 271                          * give FIFO status priority and check it one more
 272                          * time before reporting interrupt. The interrupt will
 273                          * be reported next time this function is called.
 274                          */
 275                         if (rx_transfer &&
 276                             !(readl(&i2c->usi_fifo_stat) & fifo_bit))
 277                                 break;
 278                         return I2C_NOK;
 279                 }
 280                 if (!i--) {
 281                         debug("%s: FIFO polling timeout!\n", __func__);
 282                         return I2C_NOK_TOUT;
 283                 }
 284                 udelay(1);
 285         }
 286         return I2C_OK;
 287 }
 288
 289 /*
 290  * Preapre hsi2c transaction, either read or write.
 291  *
 292  * Set up transfer as described in section 27.5.1.2 'I2C Channel Auto Mode' of
 293  * the 5420 UM.
 294  *
 295  * @param i2c: pointer to the appropriate i2c register bank.
 296  * @param chip: slave address on the i2c bus (with read/write bit exlcuded)
 297  * @param len: number of bytes expected to be sent or received
 298  * @param rx_transfer: set to true for receive transactions
 299  * @param: issue_stop: set to true if i2c stop condition should be generated
 300  *         after this transaction.
 301  * @return: I2C_NOK_TOUT in case the bus remained busy for HSI2C_TIMEOUT_US,
 302  *          I2C_OK otherwise.
 303  */
 304 static int hsi2c_prepare_transaction(struct exynos5_hsi2c *i2c,
 305                                      u8 chip,
 306                                      u16 len,
 307                                      bool rx_transfer,
 308                                      bool issue_stop)
 309 {
 310         u32 conf;
 311
 312         conf = len | HSI2C_MASTER_RUN;
 313
 314         if (issue_stop)
 315                 conf |= HSI2C_STOP_AFTER_TRANS;
 316
 317         /* Clear to enable Timeout */
 318         writel(readl(&i2c->usi_timeout) & ~HSI2C_TIMEOUT_EN, &i2c->usi_timeout);
 319
 320         /* Set slave address */
 321         writel(HSI2C_SLV_ADDR_MAS(chip), &i2c->i2c_addr);
 322
 323         if (rx_transfer) {
 324                 /* i2c master, read transaction */
 325                 writel((HSI2C_RXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
 326                        &i2c->usi_ctl);
 327
 328                 /* read up to len bytes, stop after transaction is finished */
 329                 writel(conf | HSI2C_READ_WRITE, &i2c->usi_auto_conf);
 330         } else {
 331                 /* i2c master, write transaction */
 332                 writel((HSI2C_TXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
 333                        &i2c->usi_ctl);
 334
 335                 /* write up to len bytes, stop after transaction is finished */
 336                 writel(conf, &i2c->usi_auto_conf);
 337         }
 338
 339         /* Reset all pending interrupt status bits we care about, if any */
 340         writel(HSI2C_INT_I2C_EN, &i2c->usi_int_stat);
 341
 342         return I2C_OK;
 343 }
 344
 345 /*
 346  * Wait while i2c bus is settling down (mostly stop gets completed).
 347  */
 348 static int hsi2c_wait_while_busy(struct exynos5_hsi2c *i2c)
 349 {
 350         int i = HSI2C_TIMEOUT_US;
 351
 352         while (readl(&i2c->usi_trans_status) & HSI2C_MASTER_BUSY) {
 353                 if (!i--) {
 354                         debug("%s: bus busy\n", __func__);
 355                         return I2C_NOK_TOUT;
 356                 }
 357                 udelay(1);
 358         }
 359         return I2C_OK;
 360 }
 361
 362 static int hsi2c_write(struct exynos5_hsi2c *i2c,
 363                        unsigned char chip,
 364                        unsigned char addr[],
 365                        unsigned char alen,
 366                        unsigned char data[],
 367                        unsigned short len,
 368                        bool issue_stop)
 369 {
 370         int i, rv = 0;
 371
 372         if (!(len + alen)) {
 373                 /* Writes of zero length not supported in auto mode. */
 374                 debug("%s: zero length writes not supported\n", __func__);
 375                 return I2C_NOK;
 376         }
 377
 378         rv = hsi2c_prepare_transaction
 379                 (i2c, chip, len + alen, false, issue_stop);
 380         if (rv != I2C_OK)
 381                 return rv;
 382
 383         /* Move address, if any, and the data, if any, into the FIFO. */
 384         for (i = 0; i < alen; i++) {
 385                 rv = hsi2c_poll_fifo(i2c, false);
 386                 if (rv != I2C_OK) {
 387                         debug("%s: address write failed\n", __func__);
 388                         goto write_error;
 389                 }
 390                 writel(addr[i], &i2c->usi_txdata);
 391         }
 392
 393         for (i = 0; i < len; i++) {
 394                 rv = hsi2c_poll_fifo(i2c, false);
 395                 if (rv != I2C_OK) {
 396                         debug("%s: data write failed\n", __func__);
 397                         goto write_error;
 398                 }
 399                 writel(data[i], &i2c->usi_txdata);
 400         }
 401
 402         rv = hsi2c_wait_for_trx(i2c);
 403
 404  write_error:
 405         if (issue_stop) {
 406                 int tmp_ret = hsi2c_wait_while_busy(i2c);
 407                 if (rv == I2C_OK)
 408                         rv = tmp_ret;
 409         }
 410
 411         writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
 412         return rv;
 413 }
 414
 415 static int hsi2c_read(struct exynos5_hsi2c *i2c,
 416                       unsigned char chip,
 417                       unsigned char addr[],
 418                       unsigned char alen,
 419                       unsigned char data[],
 420                       unsigned short len)
 421 {
 422         int i, rv, tmp_ret;
 423         bool drop_data = false;
 424
 425         if (!len) {
 426                 /* Reads of zero length not supported in auto mode. */
 427                 debug("%s: zero length read adjusted\n", __func__);
 428                 drop_data = true;
 429                 len = 1;
 430         }
 431
 432         if (alen) {
 433                 /* Internal register adress needs to be written first. */
 434                 rv = hsi2c_write(i2c, chip, addr, alen, NULL, 0, false);
 435                 if (rv != I2C_OK)
 436                         return rv;
 437         }
 438
 439         rv = hsi2c_prepare_transaction(i2c, chip, len, true, true);
 440
 441         if (rv != I2C_OK)
 442                 return rv;
 443
 444         for (i = 0; i < len; i++) {
 445                 rv = hsi2c_poll_fifo(i2c, true);
 446                 if (rv != I2C_OK)
 447                         goto read_err;
 448                 if (drop_data)
 449                         continue;
 450                 data[i] = readl(&i2c->usi_rxdata);
 451         }
 452
 453         rv = hsi2c_wait_for_trx(i2c);
 454
 455  read_err:
 456         tmp_ret = hsi2c_wait_while_busy(i2c);
 457         if (rv == I2C_OK)
 458                 rv = tmp_ret;
 459
 460         writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
 461         return rv;
 462 }
 463
 464 static int exynos_hs_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
 465                               int nmsgs)
 466 {
 467         struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
 468         struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
 469         int ret;
 470
 471         for (; nmsgs > 0; nmsgs--, msg++) {
 472                 if (msg->flags & I2C_M_RD) {
 473                         ret = hsi2c_read(hsregs, msg->addr, 0, 0, msg->buf,
 474                                          msg->len);
 475                 } else {
 476                         ret = hsi2c_write(hsregs, msg->addr, 0, 0, msg->buf,
 477                                           msg->len, true);
 478                 }
 479                 if (ret) {
 480                         exynos5_i2c_reset(i2c_bus);
 481                         return -EREMOTEIO;
 482                 }
 483         }
 484
 485         return 0;
 486 }
 487
 488 static int s3c24x0_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
 489 {
 490         struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
 491
 492         i2c_bus->clock_frequency = speed;
 493
 494         if (hsi2c_get_clk_details(i2c_bus))
 495                 return -EFAULT;
 496         hsi2c_ch_init(i2c_bus);
 497
 498         return 0;
 499 }
 500
 501 static int s3c24x0_i2c_probe(struct udevice *dev, uint chip, uint chip_flags)
 502 {
 503         struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
 504         uchar buf[1];
 505         int ret;
 506
 507         buf[0] = 0;
 508
 509         /*
 510          * What is needed is to send the chip address and verify that the
 511          * address was <ACK>ed (i.e. there was a chip at that address which
 512          * drove the data line low).
 513          */
 514         ret = hsi2c_read(i2c_bus->hsregs, chip, 0, 0, buf, 1);
 515
 516         return ret != I2C_OK;
 517 }
 518
 519 static int s3c_i2c_ofdata_to_platdata(struct udevice *dev)
 520 {
 521         const void *blob = gd->fdt_blob;
 522         struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
 523         int node;
 524
 525         node = dev_of_offset(dev);
 526
 527         i2c_bus->hsregs = (struct exynos5_hsi2c *)dev_get_addr(dev);
 528
 529         i2c_bus->id = pinmux_decode_periph_id(blob, node);
 530
 531         i2c_bus->clock_frequency = fdtdec_get_int(blob, node,
 532                                                   "clock-frequency", 100000);
 533         i2c_bus->node = node;
 534         i2c_bus->bus_num = dev->seq;
 535
 536         exynos_pinmux_config(i2c_bus->id, PINMUX_FLAG_HS_MODE);
 537
 538         i2c_bus->active = true;
 539
 540         return 0;
 541 }
 542
 543 static const struct dm_i2c_ops exynos_hs_i2c_ops = {
 544         .xfer           = exynos_hs_i2c_xfer,
 545         .probe_chip     = s3c24x0_i2c_probe,
 546         .set_bus_speed  = s3c24x0_i2c_set_bus_speed,
 547 };
 548
 549 static const struct udevice_id exynos_hs_i2c_ids[] = {
 550         { .compatible = "samsung,exynos5-hsi2c" },
 551         { }
 552 };
 553
 554 U_BOOT_DRIVER(hs_i2c) = {
 555         .name   = "i2c_s3c_hs",
 556         .id     = UCLASS_I2C,
 557         .of_match = exynos_hs_i2c_ids,
 558         .ofdata_to_platdata = s3c_i2c_ofdata_to_platdata,
 559         .priv_auto_alloc_size = sizeof(struct s3c24x0_i2c_bus),
 560         .ops    = &exynos_hs_i2c_ops,
 561 };