1 /* 2 * Copyright (C) 2009 ST-Ericsson SA 3 * Copyright (C) 2009 STMicroelectronics 4 * 5 * I2C master mode controller driver, used in Nomadik 8815 6 * and Ux500 platforms. 7 * 8 * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com> 9 * Author: Sachin Verma <sachin.verma@st.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 version 2, as 13 * published by the Free Software Foundation. 14 */ 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/amba/bus.h> 18 #include <linux/slab.h> 19 #include <linux/interrupt.h> 20 #include <linux/i2c.h> 21 #include <linux/err.h> 22 #include <linux/clk.h> 23 #include <linux/io.h> 24 #include <linux/pm_runtime.h> 25 #include <linux/of.h> 26 #include <linux/pinctrl/consumer.h> 27 28 #define DRIVER_NAME "nmk-i2c" 29 30 /* I2C Controller register offsets */ 31 #define I2C_CR (0x000) 32 #define I2C_SCR (0x004) 33 #define I2C_HSMCR (0x008) 34 #define I2C_MCR (0x00C) 35 #define I2C_TFR (0x010) 36 #define I2C_SR (0x014) 37 #define I2C_RFR (0x018) 38 #define I2C_TFTR (0x01C) 39 #define I2C_RFTR (0x020) 40 #define I2C_DMAR (0x024) 41 #define I2C_BRCR (0x028) 42 #define I2C_IMSCR (0x02C) 43 #define I2C_RISR (0x030) 44 #define I2C_MISR (0x034) 45 #define I2C_ICR (0x038) 46 47 /* Control registers */ 48 #define I2C_CR_PE (0x1 << 0) /* Peripheral Enable */ 49 #define I2C_CR_OM (0x3 << 1) /* Operating mode */ 50 #define I2C_CR_SAM (0x1 << 3) /* Slave addressing mode */ 51 #define I2C_CR_SM (0x3 << 4) /* Speed mode */ 52 #define I2C_CR_SGCM (0x1 << 6) /* Slave general call mode */ 53 #define I2C_CR_FTX (0x1 << 7) /* Flush Transmit */ 54 #define I2C_CR_FRX (0x1 << 8) /* Flush Receive */ 55 #define I2C_CR_DMA_TX_EN (0x1 << 9) /* DMA Tx enable */ 56 #define I2C_CR_DMA_RX_EN (0x1 << 10) /* DMA Rx Enable */ 57 #define I2C_CR_DMA_SLE (0x1 << 11) /* DMA sync. logic enable */ 58 #define I2C_CR_LM (0x1 << 12) /* Loopback mode */ 59 #define I2C_CR_FON (0x3 << 13) /* Filtering on */ 60 #define I2C_CR_FS (0x3 << 15) /* Force stop enable */ 61 62 /* Master controller (MCR) register */ 63 #define I2C_MCR_OP (0x1 << 0) /* Operation */ 64 #define I2C_MCR_A7 (0x7f << 1) /* 7-bit address */ 65 #define I2C_MCR_EA10 (0x7 << 8) /* 10-bit Extended address */ 66 #define I2C_MCR_SB (0x1 << 11) /* Extended address */ 67 #define I2C_MCR_AM (0x3 << 12) /* Address type */ 68 #define I2C_MCR_STOP (0x1 << 14) /* Stop condition */ 69 #define I2C_MCR_LENGTH (0x7ff << 15) /* Transaction length */ 70 71 /* Status register (SR) */ 72 #define I2C_SR_OP (0x3 << 0) /* Operation */ 73 #define I2C_SR_STATUS (0x3 << 2) /* controller status */ 74 #define I2C_SR_CAUSE (0x7 << 4) /* Abort cause */ 75 #define I2C_SR_TYPE (0x3 << 7) /* Receive type */ 76 #define I2C_SR_LENGTH (0x7ff << 9) /* Transfer length */ 77 78 /* Interrupt mask set/clear (IMSCR) bits */ 79 #define I2C_IT_TXFE (0x1 << 0) 80 #define I2C_IT_TXFNE (0x1 << 1) 81 #define I2C_IT_TXFF (0x1 << 2) 82 #define I2C_IT_TXFOVR (0x1 << 3) 83 #define I2C_IT_RXFE (0x1 << 4) 84 #define I2C_IT_RXFNF (0x1 << 5) 85 #define I2C_IT_RXFF (0x1 << 6) 86 #define I2C_IT_RFSR (0x1 << 16) 87 #define I2C_IT_RFSE (0x1 << 17) 88 #define I2C_IT_WTSR (0x1 << 18) 89 #define I2C_IT_MTD (0x1 << 19) 90 #define I2C_IT_STD (0x1 << 20) 91 #define I2C_IT_MAL (0x1 << 24) 92 #define I2C_IT_BERR (0x1 << 25) 93 #define I2C_IT_MTDWS (0x1 << 28) 94 95 #define GEN_MASK(val, mask, sb) (((val) << (sb)) & (mask)) 96 97 /* some bits in ICR are reserved */ 98 #define I2C_CLEAR_ALL_INTS 0x131f007f 99 100 /* first three msb bits are reserved */ 101 #define IRQ_MASK(mask) (mask & 0x1fffffff) 102 103 /* maximum threshold value */ 104 #define MAX_I2C_FIFO_THRESHOLD 15 105 106 enum i2c_freq_mode { 107 I2C_FREQ_MODE_STANDARD, /* up to 100 Kb/s */ 108 I2C_FREQ_MODE_FAST, /* up to 400 Kb/s */ 109 I2C_FREQ_MODE_HIGH_SPEED, /* up to 3.4 Mb/s */ 110 I2C_FREQ_MODE_FAST_PLUS, /* up to 1 Mb/s */ 111 }; 112 113 /** 114 * struct i2c_vendor_data - per-vendor variations 115 * @has_mtdws: variant has the MTDWS bit 116 * @fifodepth: variant FIFO depth 117 */ 118 struct i2c_vendor_data { 119 bool has_mtdws; 120 u32 fifodepth; 121 }; 122 123 enum i2c_status { 124 I2C_NOP, 125 I2C_ON_GOING, 126 I2C_OK, 127 I2C_ABORT 128 }; 129 130 /* operation */ 131 enum i2c_operation { 132 I2C_NO_OPERATION = 0xff, 133 I2C_WRITE = 0x00, 134 I2C_READ = 0x01 135 }; 136 137 /** 138 * struct i2c_nmk_client - client specific data 139 * @slave_adr: 7-bit slave address 140 * @count: no. bytes to be transferred 141 * @buffer: client data buffer 142 * @xfer_bytes: bytes transferred till now 143 * @operation: current I2C operation 144 */ 145 struct i2c_nmk_client { 146 unsigned short slave_adr; 147 unsigned long count; 148 unsigned char *buffer; 149 unsigned long xfer_bytes; 150 enum i2c_operation operation; 151 }; 152 153 /** 154 * struct nmk_i2c_dev - private data structure of the controller. 155 * @vendor: vendor data for this variant. 156 * @adev: parent amba device. 157 * @adap: corresponding I2C adapter. 158 * @irq: interrupt line for the controller. 159 * @virtbase: virtual io memory area. 160 * @clk: hardware i2c block clock. 161 * @cli: holder of client specific data. 162 * @clk_freq: clock frequency for the operation mode 163 * @tft: Tx FIFO Threshold in bytes 164 * @rft: Rx FIFO Threshold in bytes 165 * @timeout Slave response timeout (ms) 166 * @sm: speed mode 167 * @stop: stop condition. 168 * @xfer_complete: acknowledge completion for a I2C message. 169 * @result: controller propogated result. 170 */ 171 struct nmk_i2c_dev { 172 struct i2c_vendor_data *vendor; 173 struct amba_device *adev; 174 struct i2c_adapter adap; 175 int irq; 176 void __iomem *virtbase; 177 struct clk *clk; 178 struct i2c_nmk_client cli; 179 u32 clk_freq; 180 unsigned char tft; 181 unsigned char rft; 182 int timeout; 183 enum i2c_freq_mode sm; 184 int stop; 185 struct completion xfer_complete; 186 int result; 187 }; 188 189 /* controller's abort causes */ 190 static const char *abort_causes[] = { 191 "no ack received after address transmission", 192 "no ack received during data phase", 193 "ack received after xmission of master code", 194 "master lost arbitration", 195 "slave restarts", 196 "slave reset", 197 "overflow, maxsize is 2047 bytes", 198 }; 199 200 static inline void i2c_set_bit(void __iomem *reg, u32 mask) 201 { 202 writel(readl(reg) | mask, reg); 203 } 204 205 static inline void i2c_clr_bit(void __iomem *reg, u32 mask) 206 { 207 writel(readl(reg) & ~mask, reg); 208 } 209 210 /** 211 * flush_i2c_fifo() - This function flushes the I2C FIFO 212 * @dev: private data of I2C Driver 213 * 214 * This function flushes the I2C Tx and Rx FIFOs. It returns 215 * 0 on successful flushing of FIFO 216 */ 217 static int flush_i2c_fifo(struct nmk_i2c_dev *dev) 218 { 219 #define LOOP_ATTEMPTS 10 220 int i; 221 unsigned long timeout; 222 223 /* 224 * flush the transmit and receive FIFO. The flushing 225 * operation takes several cycles before to be completed. 226 * On the completion, the I2C internal logic clears these 227 * bits, until then no one must access Tx, Rx FIFO and 228 * should poll on these bits waiting for the completion. 229 */ 230 writel((I2C_CR_FTX | I2C_CR_FRX), dev->virtbase + I2C_CR); 231 232 for (i = 0; i < LOOP_ATTEMPTS; i++) { 233 timeout = jiffies + dev->adap.timeout; 234 235 while (!time_after(jiffies, timeout)) { 236 if ((readl(dev->virtbase + I2C_CR) & 237 (I2C_CR_FTX | I2C_CR_FRX)) == 0) 238 return 0; 239 } 240 } 241 242 dev_err(&dev->adev->dev, 243 "flushing operation timed out giving up after %d attempts", 244 LOOP_ATTEMPTS); 245 246 return -ETIMEDOUT; 247 } 248 249 /** 250 * disable_all_interrupts() - Disable all interrupts of this I2c Bus 251 * @dev: private data of I2C Driver 252 */ 253 static void disable_all_interrupts(struct nmk_i2c_dev *dev) 254 { 255 u32 mask = IRQ_MASK(0); 256 writel(mask, dev->virtbase + I2C_IMSCR); 257 } 258 259 /** 260 * clear_all_interrupts() - Clear all interrupts of I2C Controller 261 * @dev: private data of I2C Driver 262 */ 263 static void clear_all_interrupts(struct nmk_i2c_dev *dev) 264 { 265 u32 mask; 266 mask = IRQ_MASK(I2C_CLEAR_ALL_INTS); 267 writel(mask, dev->virtbase + I2C_ICR); 268 } 269 270 /** 271 * init_hw() - initialize the I2C hardware 272 * @dev: private data of I2C Driver 273 */ 274 static int init_hw(struct nmk_i2c_dev *dev) 275 { 276 int stat; 277 278 stat = flush_i2c_fifo(dev); 279 if (stat) 280 goto exit; 281 282 /* disable the controller */ 283 i2c_clr_bit(dev->virtbase + I2C_CR , I2C_CR_PE); 284 285 disable_all_interrupts(dev); 286 287 clear_all_interrupts(dev); 288 289 dev->cli.operation = I2C_NO_OPERATION; 290 291 exit: 292 return stat; 293 } 294 295 /* enable peripheral, master mode operation */ 296 #define DEFAULT_I2C_REG_CR ((1 << 1) | I2C_CR_PE) 297 298 /** 299 * load_i2c_mcr_reg() - load the MCR register 300 * @dev: private data of controller 301 * @flags: message flags 302 */ 303 static u32 load_i2c_mcr_reg(struct nmk_i2c_dev *dev, u16 flags) 304 { 305 u32 mcr = 0; 306 unsigned short slave_adr_3msb_bits; 307 308 mcr |= GEN_MASK(dev->cli.slave_adr, I2C_MCR_A7, 1); 309 310 if (unlikely(flags & I2C_M_TEN)) { 311 /* 10-bit address transaction */ 312 mcr |= GEN_MASK(2, I2C_MCR_AM, 12); 313 /* 314 * Get the top 3 bits. 315 * EA10 represents extended address in MCR. This includes 316 * the extension (MSB bits) of the 7 bit address loaded 317 * in A7 318 */ 319 slave_adr_3msb_bits = (dev->cli.slave_adr >> 7) & 0x7; 320 321 mcr |= GEN_MASK(slave_adr_3msb_bits, I2C_MCR_EA10, 8); 322 } else { 323 /* 7-bit address transaction */ 324 mcr |= GEN_MASK(1, I2C_MCR_AM, 12); 325 } 326 327 /* start byte procedure not applied */ 328 mcr |= GEN_MASK(0, I2C_MCR_SB, 11); 329 330 /* check the operation, master read/write? */ 331 if (dev->cli.operation == I2C_WRITE) 332 mcr |= GEN_MASK(I2C_WRITE, I2C_MCR_OP, 0); 333 else 334 mcr |= GEN_MASK(I2C_READ, I2C_MCR_OP, 0); 335 336 /* stop or repeated start? */ 337 if (dev->stop) 338 mcr |= GEN_MASK(1, I2C_MCR_STOP, 14); 339 else 340 mcr &= ~(GEN_MASK(1, I2C_MCR_STOP, 14)); 341 342 mcr |= GEN_MASK(dev->cli.count, I2C_MCR_LENGTH, 15); 343 344 return mcr; 345 } 346 347 /** 348 * setup_i2c_controller() - setup the controller 349 * @dev: private data of controller 350 */ 351 static void setup_i2c_controller(struct nmk_i2c_dev *dev) 352 { 353 u32 brcr1, brcr2; 354 u32 i2c_clk, div; 355 u32 ns; 356 u16 slsu; 357 358 writel(0x0, dev->virtbase + I2C_CR); 359 writel(0x0, dev->virtbase + I2C_HSMCR); 360 writel(0x0, dev->virtbase + I2C_TFTR); 361 writel(0x0, dev->virtbase + I2C_RFTR); 362 writel(0x0, dev->virtbase + I2C_DMAR); 363 364 i2c_clk = clk_get_rate(dev->clk); 365 366 /* 367 * set the slsu: 368 * 369 * slsu defines the data setup time after SCL clock 370 * stretching in terms of i2c clk cycles + 1 (zero means 371 * "wait one cycle"), the needed setup time for the three 372 * modes are 250ns, 100ns, 10ns respectively. 373 * 374 * As the time for one cycle T in nanoseconds is 375 * T = (1/f) * 1000000000 => 376 * slsu = cycles / (1000000000 / f) + 1 377 */ 378 ns = DIV_ROUND_UP_ULL(1000000000ULL, i2c_clk); 379 switch (dev->sm) { 380 case I2C_FREQ_MODE_FAST: 381 case I2C_FREQ_MODE_FAST_PLUS: 382 slsu = DIV_ROUND_UP(100, ns); /* Fast */ 383 break; 384 case I2C_FREQ_MODE_HIGH_SPEED: 385 slsu = DIV_ROUND_UP(10, ns); /* High */ 386 break; 387 case I2C_FREQ_MODE_STANDARD: 388 default: 389 slsu = DIV_ROUND_UP(250, ns); /* Standard */ 390 break; 391 } 392 slsu += 1; 393 394 dev_dbg(&dev->adev->dev, "calculated SLSU = %04x\n", slsu); 395 writel(slsu << 16, dev->virtbase + I2C_SCR); 396 397 /* 398 * The spec says, in case of std. mode the divider is 399 * 2 whereas it is 3 for fast and fastplus mode of 400 * operation. TODO - high speed support. 401 */ 402 div = (dev->clk_freq > 100000) ? 3 : 2; 403 404 /* 405 * generate the mask for baud rate counters. The controller 406 * has two baud rate counters. One is used for High speed 407 * operation, and the other is for std, fast mode, fast mode 408 * plus operation. Currently we do not supprt high speed mode 409 * so set brcr1 to 0. 410 */ 411 brcr1 = 0 << 16; 412 brcr2 = (i2c_clk/(dev->clk_freq * div)) & 0xffff; 413 414 /* set the baud rate counter register */ 415 writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR); 416 417 /* 418 * set the speed mode. Currently we support 419 * only standard and fast mode of operation 420 * TODO - support for fast mode plus (up to 1Mb/s) 421 * and high speed (up to 3.4 Mb/s) 422 */ 423 if (dev->sm > I2C_FREQ_MODE_FAST) { 424 dev_err(&dev->adev->dev, 425 "do not support this mode defaulting to std. mode\n"); 426 brcr2 = i2c_clk/(100000 * 2) & 0xffff; 427 writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR); 428 writel(I2C_FREQ_MODE_STANDARD << 4, 429 dev->virtbase + I2C_CR); 430 } 431 writel(dev->sm << 4, dev->virtbase + I2C_CR); 432 433 /* set the Tx and Rx FIFO threshold */ 434 writel(dev->tft, dev->virtbase + I2C_TFTR); 435 writel(dev->rft, dev->virtbase + I2C_RFTR); 436 } 437 438 /** 439 * read_i2c() - Read from I2C client device 440 * @dev: private data of I2C Driver 441 * @flags: message flags 442 * 443 * This function reads from i2c client device when controller is in 444 * master mode. There is a completion timeout. If there is no transfer 445 * before timeout error is returned. 446 */ 447 static int read_i2c(struct nmk_i2c_dev *dev, u16 flags) 448 { 449 int status = 0; 450 u32 mcr, irq_mask; 451 unsigned long timeout; 452 453 mcr = load_i2c_mcr_reg(dev, flags); 454 writel(mcr, dev->virtbase + I2C_MCR); 455 456 /* load the current CR value */ 457 writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR, 458 dev->virtbase + I2C_CR); 459 460 /* enable the controller */ 461 i2c_set_bit(dev->virtbase + I2C_CR, I2C_CR_PE); 462 463 init_completion(&dev->xfer_complete); 464 465 /* enable interrupts by setting the mask */ 466 irq_mask = (I2C_IT_RXFNF | I2C_IT_RXFF | 467 I2C_IT_MAL | I2C_IT_BERR); 468 469 if (dev->stop || !dev->vendor->has_mtdws) 470 irq_mask |= I2C_IT_MTD; 471 else 472 irq_mask |= I2C_IT_MTDWS; 473 474 irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask); 475 476 writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask, 477 dev->virtbase + I2C_IMSCR); 478 479 timeout = wait_for_completion_timeout( 480 &dev->xfer_complete, dev->adap.timeout); 481 482 if (timeout == 0) { 483 /* Controller timed out */ 484 dev_err(&dev->adev->dev, "read from slave 0x%x timed out\n", 485 dev->cli.slave_adr); 486 status = -ETIMEDOUT; 487 } 488 return status; 489 } 490 491 static void fill_tx_fifo(struct nmk_i2c_dev *dev, int no_bytes) 492 { 493 int count; 494 495 for (count = (no_bytes - 2); 496 (count > 0) && 497 (dev->cli.count != 0); 498 count--) { 499 /* write to the Tx FIFO */ 500 writeb(*dev->cli.buffer, 501 dev->virtbase + I2C_TFR); 502 dev->cli.buffer++; 503 dev->cli.count--; 504 dev->cli.xfer_bytes++; 505 } 506 507 } 508 509 /** 510 * write_i2c() - Write data to I2C client. 511 * @dev: private data of I2C Driver 512 * @flags: message flags 513 * 514 * This function writes data to I2C client 515 */ 516 static int write_i2c(struct nmk_i2c_dev *dev, u16 flags) 517 { 518 u32 status = 0; 519 u32 mcr, irq_mask; 520 unsigned long timeout; 521 522 mcr = load_i2c_mcr_reg(dev, flags); 523 524 writel(mcr, dev->virtbase + I2C_MCR); 525 526 /* load the current CR value */ 527 writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR, 528 dev->virtbase + I2C_CR); 529 530 /* enable the controller */ 531 i2c_set_bit(dev->virtbase + I2C_CR , I2C_CR_PE); 532 533 init_completion(&dev->xfer_complete); 534 535 /* enable interrupts by settings the masks */ 536 irq_mask = (I2C_IT_TXFOVR | I2C_IT_MAL | I2C_IT_BERR); 537 538 /* Fill the TX FIFO with transmit data */ 539 fill_tx_fifo(dev, MAX_I2C_FIFO_THRESHOLD); 540 541 if (dev->cli.count != 0) 542 irq_mask |= I2C_IT_TXFNE; 543 544 /* 545 * check if we want to transfer a single or multiple bytes, if so 546 * set the MTDWS bit (Master Transaction Done Without Stop) 547 * to start repeated start operation 548 */ 549 if (dev->stop || !dev->vendor->has_mtdws) 550 irq_mask |= I2C_IT_MTD; 551 else 552 irq_mask |= I2C_IT_MTDWS; 553 554 irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask); 555 556 writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask, 557 dev->virtbase + I2C_IMSCR); 558 559 timeout = wait_for_completion_timeout( 560 &dev->xfer_complete, dev->adap.timeout); 561 562 if (timeout == 0) { 563 /* Controller timed out */ 564 dev_err(&dev->adev->dev, "write to slave 0x%x timed out\n", 565 dev->cli.slave_adr); 566 status = -ETIMEDOUT; 567 } 568 569 return status; 570 } 571 572 /** 573 * nmk_i2c_xfer_one() - transmit a single I2C message 574 * @dev: device with a message encoded into it 575 * @flags: message flags 576 */ 577 static int nmk_i2c_xfer_one(struct nmk_i2c_dev *dev, u16 flags) 578 { 579 int status; 580 581 if (flags & I2C_M_RD) { 582 /* read operation */ 583 dev->cli.operation = I2C_READ; 584 status = read_i2c(dev, flags); 585 } else { 586 /* write operation */ 587 dev->cli.operation = I2C_WRITE; 588 status = write_i2c(dev, flags); 589 } 590 591 if (status || (dev->result)) { 592 u32 i2c_sr; 593 u32 cause; 594 595 i2c_sr = readl(dev->virtbase + I2C_SR); 596 /* 597 * Check if the controller I2C operation status 598 * is set to ABORT(11b). 599 */ 600 if (((i2c_sr >> 2) & 0x3) == 0x3) { 601 /* get the abort cause */ 602 cause = (i2c_sr >> 4) & 0x7; 603 dev_err(&dev->adev->dev, "%s\n", 604 cause >= ARRAY_SIZE(abort_causes) ? 605 "unknown reason" : 606 abort_causes[cause]); 607 } 608 609 (void) init_hw(dev); 610 611 status = status ? status : dev->result; 612 } 613 614 return status; 615 } 616 617 /** 618 * nmk_i2c_xfer() - I2C transfer function used by kernel framework 619 * @i2c_adap: Adapter pointer to the controller 620 * @msgs: Pointer to data to be written. 621 * @num_msgs: Number of messages to be executed 622 * 623 * This is the function called by the generic kernel i2c_transfer() 624 * or i2c_smbus...() API calls. Note that this code is protected by the 625 * semaphore set in the kernel i2c_transfer() function. 626 * 627 * NOTE: 628 * READ TRANSFER : We impose a restriction of the first message to be the 629 * index message for any read transaction. 630 * - a no index is coded as '0', 631 * - 2byte big endian index is coded as '3' 632 * !!! msg[0].buf holds the actual index. 633 * This is compatible with generic messages of smbus emulator 634 * that send a one byte index. 635 * eg. a I2C transation to read 2 bytes from index 0 636 * idx = 0; 637 * msg[0].addr = client->addr; 638 * msg[0].flags = 0x0; 639 * msg[0].len = 1; 640 * msg[0].buf = &idx; 641 * 642 * msg[1].addr = client->addr; 643 * msg[1].flags = I2C_M_RD; 644 * msg[1].len = 2; 645 * msg[1].buf = rd_buff 646 * i2c_transfer(adap, msg, 2); 647 * 648 * WRITE TRANSFER : The I2C standard interface interprets all data as payload. 649 * If you want to emulate an SMBUS write transaction put the 650 * index as first byte(or first and second) in the payload. 651 * eg. a I2C transation to write 2 bytes from index 1 652 * wr_buff[0] = 0x1; 653 * wr_buff[1] = 0x23; 654 * wr_buff[2] = 0x46; 655 * msg[0].flags = 0x0; 656 * msg[0].len = 3; 657 * msg[0].buf = wr_buff; 658 * i2c_transfer(adap, msg, 1); 659 * 660 * To read or write a block of data (multiple bytes) using SMBUS emulation 661 * please use the i2c_smbus_read_i2c_block_data() 662 * or i2c_smbus_write_i2c_block_data() API 663 */ 664 static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap, 665 struct i2c_msg msgs[], int num_msgs) 666 { 667 int status = 0; 668 int i; 669 struct nmk_i2c_dev *dev = i2c_get_adapdata(i2c_adap); 670 int j; 671 672 pm_runtime_get_sync(&dev->adev->dev); 673 674 /* Attempt three times to send the message queue */ 675 for (j = 0; j < 3; j++) { 676 /* setup the i2c controller */ 677 setup_i2c_controller(dev); 678 679 for (i = 0; i < num_msgs; i++) { 680 dev->cli.slave_adr = msgs[i].addr; 681 dev->cli.buffer = msgs[i].buf; 682 dev->cli.count = msgs[i].len; 683 dev->stop = (i < (num_msgs - 1)) ? 0 : 1; 684 dev->result = 0; 685 686 status = nmk_i2c_xfer_one(dev, msgs[i].flags); 687 if (status != 0) 688 break; 689 } 690 if (status == 0) 691 break; 692 } 693 694 pm_runtime_put_sync(&dev->adev->dev); 695 696 /* return the no. messages processed */ 697 if (status) 698 return status; 699 else 700 return num_msgs; 701 } 702 703 /** 704 * disable_interrupts() - disable the interrupts 705 * @dev: private data of controller 706 * @irq: interrupt number 707 */ 708 static int disable_interrupts(struct nmk_i2c_dev *dev, u32 irq) 709 { 710 irq = IRQ_MASK(irq); 711 writel(readl(dev->virtbase + I2C_IMSCR) & ~(I2C_CLEAR_ALL_INTS & irq), 712 dev->virtbase + I2C_IMSCR); 713 return 0; 714 } 715 716 /** 717 * i2c_irq_handler() - interrupt routine 718 * @irq: interrupt number 719 * @arg: data passed to the handler 720 * 721 * This is the interrupt handler for the i2c driver. Currently 722 * it handles the major interrupts like Rx & Tx FIFO management 723 * interrupts, master transaction interrupts, arbitration and 724 * bus error interrupts. The rest of the interrupts are treated as 725 * unhandled. 726 */ 727 static irqreturn_t i2c_irq_handler(int irq, void *arg) 728 { 729 struct nmk_i2c_dev *dev = arg; 730 u32 tft, rft; 731 u32 count; 732 u32 misr, src; 733 734 /* load Tx FIFO and Rx FIFO threshold values */ 735 tft = readl(dev->virtbase + I2C_TFTR); 736 rft = readl(dev->virtbase + I2C_RFTR); 737 738 /* read interrupt status register */ 739 misr = readl(dev->virtbase + I2C_MISR); 740 741 src = __ffs(misr); 742 switch ((1 << src)) { 743 744 /* Transmit FIFO nearly empty interrupt */ 745 case I2C_IT_TXFNE: 746 { 747 if (dev->cli.operation == I2C_READ) { 748 /* 749 * in read operation why do we care for writing? 750 * so disable the Transmit FIFO interrupt 751 */ 752 disable_interrupts(dev, I2C_IT_TXFNE); 753 } else { 754 fill_tx_fifo(dev, (MAX_I2C_FIFO_THRESHOLD - tft)); 755 /* 756 * if done, close the transfer by disabling the 757 * corresponding TXFNE interrupt 758 */ 759 if (dev->cli.count == 0) 760 disable_interrupts(dev, I2C_IT_TXFNE); 761 } 762 } 763 break; 764 765 /* 766 * Rx FIFO nearly full interrupt. 767 * This is set when the numer of entries in Rx FIFO is 768 * greater or equal than the threshold value programmed 769 * in RFT 770 */ 771 case I2C_IT_RXFNF: 772 for (count = rft; count > 0; count--) { 773 /* Read the Rx FIFO */ 774 *dev->cli.buffer = readb(dev->virtbase + I2C_RFR); 775 dev->cli.buffer++; 776 } 777 dev->cli.count -= rft; 778 dev->cli.xfer_bytes += rft; 779 break; 780 781 /* Rx FIFO full */ 782 case I2C_IT_RXFF: 783 for (count = MAX_I2C_FIFO_THRESHOLD; count > 0; count--) { 784 *dev->cli.buffer = readb(dev->virtbase + I2C_RFR); 785 dev->cli.buffer++; 786 } 787 dev->cli.count -= MAX_I2C_FIFO_THRESHOLD; 788 dev->cli.xfer_bytes += MAX_I2C_FIFO_THRESHOLD; 789 break; 790 791 /* Master Transaction Done with/without stop */ 792 case I2C_IT_MTD: 793 case I2C_IT_MTDWS: 794 if (dev->cli.operation == I2C_READ) { 795 while (!(readl(dev->virtbase + I2C_RISR) 796 & I2C_IT_RXFE)) { 797 if (dev->cli.count == 0) 798 break; 799 *dev->cli.buffer = 800 readb(dev->virtbase + I2C_RFR); 801 dev->cli.buffer++; 802 dev->cli.count--; 803 dev->cli.xfer_bytes++; 804 } 805 } 806 807 disable_all_interrupts(dev); 808 clear_all_interrupts(dev); 809 810 if (dev->cli.count) { 811 dev->result = -EIO; 812 dev_err(&dev->adev->dev, 813 "%lu bytes still remain to be xfered\n", 814 dev->cli.count); 815 (void) init_hw(dev); 816 } 817 complete(&dev->xfer_complete); 818 819 break; 820 821 /* Master Arbitration lost interrupt */ 822 case I2C_IT_MAL: 823 dev->result = -EIO; 824 (void) init_hw(dev); 825 826 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MAL); 827 complete(&dev->xfer_complete); 828 829 break; 830 831 /* 832 * Bus Error interrupt. 833 * This happens when an unexpected start/stop condition occurs 834 * during the transaction. 835 */ 836 case I2C_IT_BERR: 837 dev->result = -EIO; 838 /* get the status */ 839 if (((readl(dev->virtbase + I2C_SR) >> 2) & 0x3) == I2C_ABORT) 840 (void) init_hw(dev); 841 842 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_BERR); 843 complete(&dev->xfer_complete); 844 845 break; 846 847 /* 848 * Tx FIFO overrun interrupt. 849 * This is set when a write operation in Tx FIFO is performed and 850 * the Tx FIFO is full. 851 */ 852 case I2C_IT_TXFOVR: 853 dev->result = -EIO; 854 (void) init_hw(dev); 855 856 dev_err(&dev->adev->dev, "Tx Fifo Over run\n"); 857 complete(&dev->xfer_complete); 858 859 break; 860 861 /* unhandled interrupts by this driver - TODO*/ 862 case I2C_IT_TXFE: 863 case I2C_IT_TXFF: 864 case I2C_IT_RXFE: 865 case I2C_IT_RFSR: 866 case I2C_IT_RFSE: 867 case I2C_IT_WTSR: 868 case I2C_IT_STD: 869 dev_err(&dev->adev->dev, "unhandled Interrupt\n"); 870 break; 871 default: 872 dev_err(&dev->adev->dev, "spurious Interrupt..\n"); 873 break; 874 } 875 876 return IRQ_HANDLED; 877 } 878 879 #ifdef CONFIG_PM_SLEEP 880 static int nmk_i2c_suspend_late(struct device *dev) 881 { 882 int ret; 883 884 ret = pm_runtime_force_suspend(dev); 885 if (ret) 886 return ret; 887 888 pinctrl_pm_select_sleep_state(dev); 889 return 0; 890 } 891 892 static int nmk_i2c_resume_early(struct device *dev) 893 { 894 return pm_runtime_force_resume(dev); 895 } 896 #endif 897 898 #ifdef CONFIG_PM 899 static int nmk_i2c_runtime_suspend(struct device *dev) 900 { 901 struct amba_device *adev = to_amba_device(dev); 902 struct nmk_i2c_dev *nmk_i2c = amba_get_drvdata(adev); 903 904 clk_disable_unprepare(nmk_i2c->clk); 905 pinctrl_pm_select_idle_state(dev); 906 return 0; 907 } 908 909 static int nmk_i2c_runtime_resume(struct device *dev) 910 { 911 struct amba_device *adev = to_amba_device(dev); 912 struct nmk_i2c_dev *nmk_i2c = amba_get_drvdata(adev); 913 int ret; 914 915 ret = clk_prepare_enable(nmk_i2c->clk); 916 if (ret) { 917 dev_err(dev, "can't prepare_enable clock\n"); 918 return ret; 919 } 920 921 pinctrl_pm_select_default_state(dev); 922 923 ret = init_hw(nmk_i2c); 924 if (ret) { 925 clk_disable_unprepare(nmk_i2c->clk); 926 pinctrl_pm_select_idle_state(dev); 927 } 928 929 return ret; 930 } 931 #endif 932 933 static const struct dev_pm_ops nmk_i2c_pm = { 934 SET_LATE_SYSTEM_SLEEP_PM_OPS(nmk_i2c_suspend_late, nmk_i2c_resume_early) 935 SET_RUNTIME_PM_OPS(nmk_i2c_runtime_suspend, 936 nmk_i2c_runtime_resume, 937 NULL) 938 }; 939 940 static unsigned int nmk_i2c_functionality(struct i2c_adapter *adap) 941 { 942 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR; 943 } 944 945 static const struct i2c_algorithm nmk_i2c_algo = { 946 .master_xfer = nmk_i2c_xfer, 947 .functionality = nmk_i2c_functionality 948 }; 949 950 static void nmk_i2c_of_probe(struct device_node *np, 951 struct nmk_i2c_dev *nmk) 952 { 953 /* Default to 100 kHz if no frequency is given in the node */ 954 if (of_property_read_u32(np, "clock-frequency", &nmk->clk_freq)) 955 nmk->clk_freq = 100000; 956 957 /* This driver only supports 'standard' and 'fast' modes of operation. */ 958 if (nmk->clk_freq <= 100000) 959 nmk->sm = I2C_FREQ_MODE_STANDARD; 960 else 961 nmk->sm = I2C_FREQ_MODE_FAST; 962 nmk->tft = 1; /* Tx FIFO threshold */ 963 nmk->rft = 8; /* Rx FIFO threshold */ 964 nmk->timeout = 200; /* Slave response timeout(ms) */ 965 } 966 967 static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id) 968 { 969 int ret = 0; 970 struct device_node *np = adev->dev.of_node; 971 struct nmk_i2c_dev *dev; 972 struct i2c_adapter *adap; 973 struct i2c_vendor_data *vendor = id->data; 974 u32 max_fifo_threshold = (vendor->fifodepth / 2) - 1; 975 976 dev = devm_kzalloc(&adev->dev, sizeof(struct nmk_i2c_dev), GFP_KERNEL); 977 if (!dev) { 978 dev_err(&adev->dev, "cannot allocate memory\n"); 979 ret = -ENOMEM; 980 goto err_no_mem; 981 } 982 dev->vendor = vendor; 983 dev->adev = adev; 984 nmk_i2c_of_probe(np, dev); 985 986 if (dev->tft > max_fifo_threshold) { 987 dev_warn(&adev->dev, "requested TX FIFO threshold %u, adjusted down to %u\n", 988 dev->tft, max_fifo_threshold); 989 dev->tft = max_fifo_threshold; 990 } 991 992 if (dev->rft > max_fifo_threshold) { 993 dev_warn(&adev->dev, "requested RX FIFO threshold %u, adjusted down to %u\n", 994 dev->rft, max_fifo_threshold); 995 dev->rft = max_fifo_threshold; 996 } 997 998 amba_set_drvdata(adev, dev); 999 1000 dev->virtbase = devm_ioremap(&adev->dev, adev->res.start, 1001 resource_size(&adev->res)); 1002 if (!dev->virtbase) { 1003 ret = -ENOMEM; 1004 goto err_no_mem; 1005 } 1006 1007 dev->irq = adev->irq[0]; 1008 ret = devm_request_irq(&adev->dev, dev->irq, i2c_irq_handler, 0, 1009 DRIVER_NAME, dev); 1010 if (ret) { 1011 dev_err(&adev->dev, "cannot claim the irq %d\n", dev->irq); 1012 goto err_no_mem; 1013 } 1014 1015 dev->clk = devm_clk_get(&adev->dev, NULL); 1016 if (IS_ERR(dev->clk)) { 1017 dev_err(&adev->dev, "could not get i2c clock\n"); 1018 ret = PTR_ERR(dev->clk); 1019 goto err_no_mem; 1020 } 1021 1022 ret = clk_prepare_enable(dev->clk); 1023 if (ret) { 1024 dev_err(&adev->dev, "can't prepare_enable clock\n"); 1025 goto err_no_mem; 1026 } 1027 1028 init_hw(dev); 1029 1030 adap = &dev->adap; 1031 adap->dev.of_node = np; 1032 adap->dev.parent = &adev->dev; 1033 adap->owner = THIS_MODULE; 1034 adap->class = I2C_CLASS_DEPRECATED; 1035 adap->algo = &nmk_i2c_algo; 1036 adap->timeout = msecs_to_jiffies(dev->timeout); 1037 snprintf(adap->name, sizeof(adap->name), 1038 "Nomadik I2C at %pR", &adev->res); 1039 1040 i2c_set_adapdata(adap, dev); 1041 1042 dev_info(&adev->dev, 1043 "initialize %s on virtual base %p\n", 1044 adap->name, dev->virtbase); 1045 1046 ret = i2c_add_adapter(adap); 1047 if (ret) 1048 goto err_no_adap; 1049 1050 pm_runtime_put(&adev->dev); 1051 1052 return 0; 1053 1054 err_no_adap: 1055 clk_disable_unprepare(dev->clk); 1056 err_no_mem: 1057 1058 return ret; 1059 } 1060 1061 static int nmk_i2c_remove(struct amba_device *adev) 1062 { 1063 struct resource *res = &adev->res; 1064 struct nmk_i2c_dev *dev = amba_get_drvdata(adev); 1065 1066 i2c_del_adapter(&dev->adap); 1067 flush_i2c_fifo(dev); 1068 disable_all_interrupts(dev); 1069 clear_all_interrupts(dev); 1070 /* disable the controller */ 1071 i2c_clr_bit(dev->virtbase + I2C_CR, I2C_CR_PE); 1072 clk_disable_unprepare(dev->clk); 1073 release_mem_region(res->start, resource_size(res)); 1074 1075 return 0; 1076 } 1077 1078 static struct i2c_vendor_data vendor_stn8815 = { 1079 .has_mtdws = false, 1080 .fifodepth = 16, /* Guessed from TFTR/RFTR = 7 */ 1081 }; 1082 1083 static struct i2c_vendor_data vendor_db8500 = { 1084 .has_mtdws = true, 1085 .fifodepth = 32, /* Guessed from TFTR/RFTR = 15 */ 1086 }; 1087 1088 static const struct amba_id nmk_i2c_ids[] = { 1089 { 1090 .id = 0x00180024, 1091 .mask = 0x00ffffff, 1092 .data = &vendor_stn8815, 1093 }, 1094 { 1095 .id = 0x00380024, 1096 .mask = 0x00ffffff, 1097 .data = &vendor_db8500, 1098 }, 1099 {}, 1100 }; 1101 1102 MODULE_DEVICE_TABLE(amba, nmk_i2c_ids); 1103 1104 static struct amba_driver nmk_i2c_driver = { 1105 .drv = { 1106 .owner = THIS_MODULE, 1107 .name = DRIVER_NAME, 1108 .pm = &nmk_i2c_pm, 1109 }, 1110 .id_table = nmk_i2c_ids, 1111 .probe = nmk_i2c_probe, 1112 .remove = nmk_i2c_remove, 1113 }; 1114 1115 static int __init nmk_i2c_init(void) 1116 { 1117 return amba_driver_register(&nmk_i2c_driver); 1118 } 1119 1120 static void __exit nmk_i2c_exit(void) 1121 { 1122 amba_driver_unregister(&nmk_i2c_driver); 1123 } 1124 1125 subsys_initcall(nmk_i2c_init); 1126 module_exit(nmk_i2c_exit); 1127 1128 MODULE_AUTHOR("Sachin Verma, Srinidhi KASAGAR"); 1129 MODULE_DESCRIPTION("Nomadik/Ux500 I2C driver"); 1130 MODULE_LICENSE("GPL"); 1131