drivers/i2c/imx_lpi2c.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright 2016 Freescale Semiconductors, Inc.
   4  */
   5
   6 #include <common.h>
   7 #include <errno.h>
   8 #include <asm/io.h>
   9 #include <asm/arch/clock.h>
  10 #include <asm/arch/imx-regs.h>
  11 #include <imx_lpi2c.h>
  12 #include <asm/arch/sys_proto.h>
  13 #include <dm.h>
  14 #include <fdtdec.h>
  15 #include <i2c.h>
  16
  17 #define LPI2C_FIFO_SIZE 4
  18 #define LPI2C_NACK_TOUT_MS 1
  19 #define LPI2C_TIMEOUT_MS 100
  20
  21 static int bus_i2c_init(struct udevice *bus, int speed);
  22
  23 /* Weak linked function for overridden by some SoC power function */
  24 int __weak init_i2c_power(unsigned i2c_num)
  25 {
  26         return 0;
  27 }
  28
  29 static int imx_lpci2c_check_busy_bus(const struct imx_lpi2c_reg *regs)
  30 {
  31         lpi2c_status_t result = LPI2C_SUCESS;
  32         u32 status;
  33
  34         status = readl(&regs->msr);
  35
  36         if ((status & LPI2C_MSR_BBF_MASK) && !(status & LPI2C_MSR_MBF_MASK))
  37                 result = LPI2C_BUSY;
  38
  39         return result;
  40 }
  41
  42 static int imx_lpci2c_check_clear_error(struct imx_lpi2c_reg *regs)
  43 {
  44         lpi2c_status_t result = LPI2C_SUCESS;
  45         u32 val, status;
  46
  47         status = readl(&regs->msr);
  48         /* errors to check for */
  49         status &= LPI2C_MSR_NDF_MASK | LPI2C_MSR_ALF_MASK |
  50                 LPI2C_MSR_FEF_MASK | LPI2C_MSR_PLTF_MASK;
  51
  52         if (status) {
  53                 if (status & LPI2C_MSR_PLTF_MASK)
  54                         result = LPI2C_PIN_LOW_TIMEOUT_ERR;
  55                 else if (status & LPI2C_MSR_ALF_MASK)
  56                         result = LPI2C_ARB_LOST_ERR;
  57                 else if (status & LPI2C_MSR_NDF_MASK)
  58                         result = LPI2C_NAK_ERR;
  59                 else if (status & LPI2C_MSR_FEF_MASK)
  60                         result = LPI2C_FIFO_ERR;
  61
  62                 /* clear status flags */
  63                 writel(0x7f00, &regs->msr);
  64                 /* reset fifos */
  65                 val = readl(&regs->mcr);
  66                 val |= LPI2C_MCR_RRF_MASK | LPI2C_MCR_RTF_MASK;
  67                 writel(val, &regs->mcr);
  68         }
  69
  70         return result;
  71 }
  72
  73 static int bus_i2c_wait_for_tx_ready(struct imx_lpi2c_reg *regs)
  74 {
  75         lpi2c_status_t result = LPI2C_SUCESS;
  76         u32 txcount = 0;
  77         ulong start_time = get_timer(0);
  78
  79         do {
  80                 txcount = LPI2C_MFSR_TXCOUNT(readl(&regs->mfsr));
  81                 txcount = LPI2C_FIFO_SIZE - txcount;
  82                 result = imx_lpci2c_check_clear_error(regs);
  83                 if (result) {
  84                         debug("i2c: wait for tx ready: result 0x%x\n", result);
  85                         return result;
  86                 }
  87                 if (get_timer(start_time) > LPI2C_TIMEOUT_MS) {
  88                         debug("i2c: wait for tx ready: timeout\n");
  89                         return -1;
  90                 }
  91         } while (!txcount);
  92
  93         return result;
  94 }
  95
  96 static int bus_i2c_send(struct udevice *bus, u8 *txbuf, int len)
  97 {
  98         struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
  99         lpi2c_status_t result = LPI2C_SUCESS;
 100
 101         /* empty tx */
 102         if (!len)
 103                 return result;
 104
 105         while (len--) {
 106                 result = bus_i2c_wait_for_tx_ready(regs);
 107                 if (result) {
 108                         debug("i2c: send wait for tx ready: %d\n", result);
 109                         return result;
 110                 }
 111                 writel(*txbuf++, &regs->mtdr);
 112         }
 113
 114         return result;
 115 }
 116
 117 static int bus_i2c_receive(struct udevice *bus, u8 *rxbuf, int len)
 118 {
 119         struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 120         lpi2c_status_t result = LPI2C_SUCESS;
 121         u32 val;
 122         ulong start_time = get_timer(0);
 123
 124         /* empty read */
 125         if (!len)
 126                 return result;
 127
 128         result = bus_i2c_wait_for_tx_ready(regs);
 129         if (result) {
 130                 debug("i2c: receive wait fot tx ready: %d\n", result);
 131                 return result;
 132         }
 133
 134         /* clear all status flags */
 135         writel(0x7f00, &regs->msr);
 136         /* send receive command */
 137         val = LPI2C_MTDR_CMD(0x1) | LPI2C_MTDR_DATA(len - 1);
 138         writel(val, &regs->mtdr);
 139
 140         while (len--) {
 141                 do {
 142                         result = imx_lpci2c_check_clear_error(regs);
 143                         if (result) {
 144                                 debug("i2c: receive check clear error: %d\n",
 145                                       result);
 146                                 return result;
 147                         }
 148                         if (get_timer(start_time) > LPI2C_TIMEOUT_MS) {
 149                                 debug("i2c: receive mrdr: timeout\n");
 150                                 return -1;
 151                         }
 152                         val = readl(&regs->mrdr);
 153                 } while (val & LPI2C_MRDR_RXEMPTY_MASK);
 154                 *rxbuf++ = LPI2C_MRDR_DATA(val);
 155         }
 156
 157         return result;
 158 }
 159
 160 static int bus_i2c_start(struct udevice *bus, u8 addr, u8 dir)
 161 {
 162         lpi2c_status_t result;
 163         struct imx_lpi2c_reg *regs =
 164                 (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 165         u32 val;
 166
 167         result = imx_lpci2c_check_busy_bus(regs);
 168         if (result) {
 169                 debug("i2c: start check busy bus: 0x%x\n", result);
 170
 171                 /* Try to init the lpi2c then check the bus busy again */
 172                 bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
 173                 result = imx_lpci2c_check_busy_bus(regs);
 174                 if (result) {
 175                         printf("i2c: Error check busy bus: 0x%x\n", result);
 176                         return result;
 177                 }
 178         }
 179         /* clear all status flags */
 180         writel(0x7f00, &regs->msr);
 181         /* turn off auto-stop condition */
 182         val = readl(&regs->mcfgr1) & ~LPI2C_MCFGR1_AUTOSTOP_MASK;
 183         writel(val, &regs->mcfgr1);
 184         /* wait tx fifo ready */
 185         result = bus_i2c_wait_for_tx_ready(regs);
 186         if (result) {
 187                 debug("i2c: start wait for tx ready: 0x%x\n", result);
 188                 return result;
 189         }
 190         /* issue start command */
 191         val = LPI2C_MTDR_CMD(0x4) | (addr << 0x1) | dir;
 192         writel(val, &regs->mtdr);
 193
 194         return result;
 195 }
 196
 197 static int bus_i2c_stop(struct udevice *bus)
 198 {
 199         lpi2c_status_t result;
 200         struct imx_lpi2c_reg *regs =
 201                 (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 202         u32 status;
 203         ulong start_time;
 204
 205         result = bus_i2c_wait_for_tx_ready(regs);
 206         if (result) {
 207                 debug("i2c: stop wait for tx ready: 0x%x\n", result);
 208                 return result;
 209         }
 210
 211         /* send stop command */
 212         writel(LPI2C_MTDR_CMD(0x2), &regs->mtdr);
 213
 214         start_time = get_timer(0);
 215         while (1) {
 216                 status = readl(&regs->msr);
 217                 result = imx_lpci2c_check_clear_error(regs);
 218                 /* stop detect flag */
 219                 if (status & LPI2C_MSR_SDF_MASK) {
 220                         /* clear stop flag */
 221                         status &= LPI2C_MSR_SDF_MASK;
 222                         writel(status, &regs->msr);
 223                         break;
 224                 }
 225
 226                 if (get_timer(start_time) > LPI2C_NACK_TOUT_MS) {
 227                         debug("stop timeout\n");
 228                         return -ETIMEDOUT;
 229                 }
 230         }
 231
 232         return result;
 233 }
 234
 235 static int bus_i2c_read(struct udevice *bus, u32 chip, u8 *buf, int len)
 236 {
 237         lpi2c_status_t result;
 238
 239         result = bus_i2c_start(bus, chip, 1);
 240         if (result)
 241                 return result;
 242         result = bus_i2c_receive(bus, buf, len);
 243         if (result)
 244                 return result;
 245
 246         return result;
 247 }
 248
 249 static int bus_i2c_write(struct udevice *bus, u32 chip, u8 *buf, int len)
 250 {
 251         lpi2c_status_t result;
 252
 253         result = bus_i2c_start(bus, chip, 0);
 254         if (result)
 255                 return result;
 256         result = bus_i2c_send(bus, buf, len);
 257         if (result)
 258                 return result;
 259
 260         return result;
 261 }
 262
 263
 264 u32 __weak imx_get_i2cclk(u32 i2c_num)
 265 {
 266         return 0;
 267 }
 268
 269 static int bus_i2c_set_bus_speed(struct udevice *bus, int speed)
 270 {
 271         struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
 272         struct imx_lpi2c_reg *regs;
 273         u32 val;
 274         u32 preescale = 0, best_pre = 0, clkhi = 0;
 275         u32 best_clkhi = 0, abs_error = 0, rate;
 276         u32 error = 0xffffffff;
 277         u32 clock_rate;
 278         bool mode;
 279         int i;
 280
 281         regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 282
 283         if (IS_ENABLED(CONFIG_CLK)) {
 284                 clock_rate = clk_get_rate(&i2c_bus->per_clk);
 285                 if (clock_rate <= 0) {
 286                         dev_err(bus, "Failed to get i2c clk: %d\n", clock_rate);
 287                         return clock_rate;
 288                 }
 289         } else {
 290                 clock_rate = imx_get_i2cclk(bus->seq);
 291                 if (!clock_rate)
 292                         return -EPERM;
 293         }
 294
 295         mode = (readl(&regs->mcr) & LPI2C_MCR_MEN_MASK) >> LPI2C_MCR_MEN_SHIFT;
 296         /* disable master mode */
 297         val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
 298         writel(val | LPI2C_MCR_MEN(0), &regs->mcr);
 299
 300         for (preescale = 1; (preescale <= 128) &&
 301                 (error != 0); preescale = 2 * preescale) {
 302                 for (clkhi = 1; clkhi < 32; clkhi++) {
 303                         if (clkhi == 1)
 304                                 rate = (clock_rate / preescale) / (1 + 3 + 2 + 2 / preescale);
 305                         else
 306                                 rate = (clock_rate / preescale / (3 * clkhi + 2 + 2 / preescale));
 307
 308                         abs_error = speed > rate ? speed - rate : rate - speed;
 309
 310                         if (abs_error < error) {
 311                                 best_pre = preescale;
 312                                 best_clkhi = clkhi;
 313                                 error = abs_error;
 314                                 if (abs_error == 0)
 315                                         break;
 316                         }
 317                 }
 318         }
 319
 320         /* Standard, fast, fast mode plus and ultra-fast transfers. */
 321         val = LPI2C_MCCR0_CLKHI(best_clkhi);
 322         if (best_clkhi < 2)
 323                 val |= LPI2C_MCCR0_CLKLO(3) | LPI2C_MCCR0_SETHOLD(2) | LPI2C_MCCR0_DATAVD(1);
 324         else
 325                 val |= LPI2C_MCCR0_CLKLO(2 * best_clkhi) | LPI2C_MCCR0_SETHOLD(best_clkhi) |
 326                         LPI2C_MCCR0_DATAVD(best_clkhi / 2);
 327         writel(val, &regs->mccr0);
 328
 329         for (i = 0; i < 8; i++) {
 330                 if (best_pre == (1 << i)) {
 331                         best_pre = i;
 332                         break;
 333                 }
 334         }
 335
 336         val = readl(&regs->mcfgr1) & ~LPI2C_MCFGR1_PRESCALE_MASK;
 337         writel(val | LPI2C_MCFGR1_PRESCALE(best_pre), &regs->mcfgr1);
 338
 339         if (mode) {
 340                 val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
 341                 writel(val | LPI2C_MCR_MEN(1), &regs->mcr);
 342         }
 343
 344         return 0;
 345 }
 346
 347 static int bus_i2c_init(struct udevice *bus, int speed)
 348 {
 349         struct imx_lpi2c_reg *regs;
 350         u32 val;
 351         int ret;
 352
 353         regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 354         /* reset peripheral */
 355         writel(LPI2C_MCR_RST_MASK, &regs->mcr);
 356         writel(0x0, &regs->mcr);
 357         /* Disable Dozen mode */
 358         writel(LPI2C_MCR_DBGEN(0) | LPI2C_MCR_DOZEN(1), &regs->mcr);
 359         /* host request disable, active high, external pin */
 360         val = readl(&regs->mcfgr0);
 361         val &= (~(LPI2C_MCFGR0_HREN_MASK | LPI2C_MCFGR0_HRPOL_MASK |
 362                                 LPI2C_MCFGR0_HRSEL_MASK));
 363         val |= LPI2C_MCFGR0_HRPOL(0x1);
 364         writel(val, &regs->mcfgr0);
 365         /* pincfg and ignore ack */
 366         val = readl(&regs->mcfgr1);
 367         val &= ~(LPI2C_MCFGR1_PINCFG_MASK | LPI2C_MCFGR1_IGNACK_MASK);
 368         val |= LPI2C_MCFGR1_PINCFG(0x0); /* 2 pin open drain */
 369         val |= LPI2C_MCFGR1_IGNACK(0x0); /* ignore nack */
 370         writel(val, &regs->mcfgr1);
 371
 372         ret = bus_i2c_set_bus_speed(bus, speed);
 373
 374         /* enable lpi2c in master mode */
 375         val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
 376         writel(val | LPI2C_MCR_MEN(1), &regs->mcr);
 377
 378         debug("i2c : controller bus %d, speed %d:\n", bus->seq, speed);
 379
 380         return ret;
 381 }
 382
 383 static int imx_lpi2c_probe_chip(struct udevice *bus, u32 chip,
 384                                 u32 chip_flags)
 385 {
 386         lpi2c_status_t result;
 387
 388         result = bus_i2c_start(bus, chip, 0);
 389         if (result) {
 390                 bus_i2c_stop(bus);
 391                 bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
 392                 return result;
 393         }
 394
 395         result = bus_i2c_stop(bus);
 396         if (result)
 397                 bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
 398
 399         return result;
 400 }
 401
 402 static int imx_lpi2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
 403 {
 404         int ret = 0, ret_stop;
 405
 406         for (; nmsgs > 0; nmsgs--, msg++) {
 407                 debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
 408                 if (msg->flags & I2C_M_RD)
 409                         ret = bus_i2c_read(bus, msg->addr, msg->buf, msg->len);
 410                 else {
 411                         ret = bus_i2c_write(bus, msg->addr, msg->buf,
 412                                             msg->len);
 413                         if (ret)
 414                                 break;
 415                 }
 416         }
 417
 418         if (ret)
 419                 debug("i2c_write: error sending\n");
 420
 421         ret_stop = bus_i2c_stop(bus);
 422         if (ret_stop)
 423                 debug("i2c_xfer: stop bus error\n");
 424
 425         ret |= ret_stop;
 426
 427         return ret;
 428 }
 429
 430 static int imx_lpi2c_set_bus_speed(struct udevice *bus, unsigned int speed)
 431 {
 432         return bus_i2c_set_bus_speed(bus, speed);
 433 }
 434
 435 __weak int enable_i2c_clk(unsigned char enable, unsigned int i2c_num)
 436 {
 437         return 0;
 438 }
 439
 440 static int imx_lpi2c_probe(struct udevice *bus)
 441 {
 442         struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
 443         fdt_addr_t addr;
 444         int ret;
 445
 446         i2c_bus->driver_data = dev_get_driver_data(bus);
 447
 448         addr = devfdt_get_addr(bus);
 449         if (addr == FDT_ADDR_T_NONE)
 450                 return -EINVAL;
 451
 452         i2c_bus->base = addr;
 453         i2c_bus->index = bus->seq;
 454         i2c_bus->bus = bus;
 455
 456         /* power up i2c resource */
 457         ret = init_i2c_power(bus->seq);
 458         if (ret) {
 459                 debug("init_i2c_power err = %d\n", ret);
 460                 return ret;
 461         }
 462
 463         if (IS_ENABLED(CONFIG_CLK)) {
 464                 ret = clk_get_by_name(bus, "per", &i2c_bus->per_clk);
 465                 if (ret) {
 466                         dev_err(bus, "Failed to get per clk\n");
 467                         return ret;
 468                 }
 469                 ret = clk_enable(&i2c_bus->per_clk);
 470                 if (ret) {
 471                         dev_err(bus, "Failed to enable per clk\n");
 472                         return ret;
 473                 }
 474
 475                 ret = clk_get_by_name(bus, "ipg", &i2c_bus->ipg_clk);
 476                 if (ret) {
 477                         dev_err(bus, "Failed to get ipg clk\n");
 478                         return ret;
 479                 }
 480                 ret = clk_enable(&i2c_bus->ipg_clk);
 481                 if (ret) {
 482                         dev_err(bus, "Failed to enable ipg clk\n");
 483                         return ret;
 484                 }
 485         } else {
 486                 /* To i.MX7ULP, only i2c4-7 can be handled by A7 core */
 487                 ret = enable_i2c_clk(1, bus->seq);
 488                 if (ret < 0)
 489                         return ret;
 490         }
 491
 492         ret = bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
 493         if (ret < 0)
 494                 return ret;
 495
 496         debug("i2c : controller bus %d at 0x%lx , speed %d: ",
 497               bus->seq, i2c_bus->base,
 498               i2c_bus->speed);
 499
 500         return 0;
 501 }
 502
 503 static const struct dm_i2c_ops imx_lpi2c_ops = {
 504         .xfer           = imx_lpi2c_xfer,
 505         .probe_chip     = imx_lpi2c_probe_chip,
 506         .set_bus_speed  = imx_lpi2c_set_bus_speed,
 507 };
 508
 509 static const struct udevice_id imx_lpi2c_ids[] = {
 510         { .compatible = "fsl,imx7ulp-lpi2c", },
 511         { .compatible = "fsl,imx8qm-lpi2c", },
 512         {}
 513 };
 514
 515 U_BOOT_DRIVER(imx_lpi2c) = {
 516         .name = "imx_lpi2c",
 517         .id = UCLASS_I2C,
 518         .of_match = imx_lpi2c_ids,
 519         .probe = imx_lpi2c_probe,
 520         .priv_auto_alloc_size = sizeof(struct imx_lpi2c_bus),
 521         .ops = &imx_lpi2c_ops,
 522 };