1/* 2 * Copyright (C) 2009 ST-Ericsson 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/platform_device.h> 18#include <linux/delay.h> 19#include <linux/slab.h> 20#include <linux/interrupt.h> 21#include <linux/i2c.h> 22#include <linux/err.h> 23#include <linux/clk.h> 24#include <linux/io.h> 25 26#include <plat/i2c.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 106enum i2c_status { 107 I2C_NOP, 108 I2C_ON_GOING, 109 I2C_OK, 110 I2C_ABORT 111}; 112 113/* operation */ 114enum i2c_operation { 115 I2C_NO_OPERATION = 0xff, 116 I2C_WRITE = 0x00, 117 I2C_READ = 0x01 118}; 119 120/* controller response timeout in ms */ 121#define I2C_TIMEOUT_MS 500 122 123/** 124 * struct i2c_nmk_client - client specific data 125 * @slave_adr: 7-bit slave address 126 * @count: no. bytes to be transfered 127 * @buffer: client data buffer 128 * @xfer_bytes: bytes transfered till now 129 * @operation: current I2C operation 130 */ 131struct i2c_nmk_client { 132 unsigned short slave_adr; 133 unsigned long count; 134 unsigned char *buffer; 135 unsigned long xfer_bytes; 136 enum i2c_operation operation; 137}; 138 139/** 140 * struct nmk_i2c_dev - private data structure of the controller 141 * @pdev: parent platform device 142 * @adap: corresponding I2C adapter 143 * @irq: interrupt line for the controller 144 * @virtbase: virtual io memory area 145 * @clk: hardware i2c block clock 146 * @cfg: machine provided controller configuration 147 * @cli: holder of client specific data 148 * @stop: stop condition 149 * @xfer_complete: acknowledge completion for a I2C message 150 * @result: controller propogated result 151 */ 152struct nmk_i2c_dev { 153 struct platform_device *pdev; 154 struct i2c_adapter adap; 155 int irq; 156 void __iomem *virtbase; 157 struct clk *clk; 158 struct nmk_i2c_controller cfg; 159 struct i2c_nmk_client cli; 160 int stop; 161 struct completion xfer_complete; 162 int result; 163}; 164 165/* controller's abort causes */ 166static const char *abort_causes[] = { 167 "no ack received after address transmission", 168 "no ack received during data phase", 169 "ack received after xmission of master code", 170 "master lost arbitration", 171 "slave restarts", 172 "slave reset", 173 "overflow, maxsize is 2047 bytes", 174}; 175 176static inline void i2c_set_bit(void __iomem *reg, u32 mask) 177{ 178 writel(readl(reg) | mask, reg); 179} 180 181static inline void i2c_clr_bit(void __iomem *reg, u32 mask) 182{ 183 writel(readl(reg) & ~mask, reg); 184} 185 186/** 187 * flush_i2c_fifo() - This function flushes the I2C FIFO 188 * @dev: private data of I2C Driver 189 * 190 * This function flushes the I2C Tx and Rx FIFOs. It returns 191 * 0 on successful flushing of FIFO 192 */ 193static int flush_i2c_fifo(struct nmk_i2c_dev *dev) 194{ 195#define LOOP_ATTEMPTS 10 196 int i; 197 unsigned long timeout; 198 199 /* 200 * flush the transmit and receive FIFO. The flushing 201 * operation takes several cycles before to be completed. 202 * On the completion, the I2C internal logic clears these 203 * bits, until then no one must access Tx, Rx FIFO and 204 * should poll on these bits waiting for the completion. 205 */ 206 writel((I2C_CR_FTX | I2C_CR_FRX), dev->virtbase + I2C_CR); 207 208 for (i = 0; i < LOOP_ATTEMPTS; i++) { 209 timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT_MS); 210 211 while (!time_after(jiffies, timeout)) { 212 if ((readl(dev->virtbase + I2C_CR) & 213 (I2C_CR_FTX | I2C_CR_FRX)) == 0) 214 return 0; 215 } 216 } 217 218 dev_err(&dev->pdev->dev, "flushing operation timed out " 219 "giving up after %d attempts", LOOP_ATTEMPTS); 220 221 return -ETIMEDOUT; 222} 223 224/** 225 * disable_all_interrupts() - Disable all interrupts of this I2c Bus 226 * @dev: private data of I2C Driver 227 */ 228static void disable_all_interrupts(struct nmk_i2c_dev *dev) 229{ 230 u32 mask = IRQ_MASK(0); 231 writel(mask, dev->virtbase + I2C_IMSCR); 232} 233 234/** 235 * clear_all_interrupts() - Clear all interrupts of I2C Controller 236 * @dev: private data of I2C Driver 237 */ 238static void clear_all_interrupts(struct nmk_i2c_dev *dev) 239{ 240 u32 mask; 241 mask = IRQ_MASK(I2C_CLEAR_ALL_INTS); 242 writel(mask, dev->virtbase + I2C_ICR); 243} 244 245/** 246 * init_hw() - initialize the I2C hardware 247 * @dev: private data of I2C Driver 248 */ 249static int init_hw(struct nmk_i2c_dev *dev) 250{ 251 int stat; 252 253 stat = flush_i2c_fifo(dev); 254 if (stat) 255 return stat; 256 257 /* disable the controller */ 258 i2c_clr_bit(dev->virtbase + I2C_CR , I2C_CR_PE); 259 260 disable_all_interrupts(dev); 261 262 clear_all_interrupts(dev); 263 264 dev->cli.operation = I2C_NO_OPERATION; 265 266 return 0; 267} 268 269/* enable peripheral, master mode operation */ 270#define DEFAULT_I2C_REG_CR ((1 << 1) | I2C_CR_PE) 271 272/** 273 * load_i2c_mcr_reg() - load the MCR register 274 * @dev: private data of controller 275 */ 276static u32 load_i2c_mcr_reg(struct nmk_i2c_dev *dev) 277{ 278 u32 mcr = 0; 279 280 /* 7-bit address transaction */ 281 mcr |= GEN_MASK(1, I2C_MCR_AM, 12); 282 mcr |= GEN_MASK(dev->cli.slave_adr, I2C_MCR_A7, 1); 283 284 /* start byte procedure not applied */ 285 mcr |= GEN_MASK(0, I2C_MCR_SB, 11); 286 287 /* check the operation, master read/write? */ 288 if (dev->cli.operation == I2C_WRITE) 289 mcr |= GEN_MASK(I2C_WRITE, I2C_MCR_OP, 0); 290 else 291 mcr |= GEN_MASK(I2C_READ, I2C_MCR_OP, 0); 292 293 /* stop or repeated start? */ 294 if (dev->stop) 295 mcr |= GEN_MASK(1, I2C_MCR_STOP, 14); 296 else 297 mcr &= ~(GEN_MASK(1, I2C_MCR_STOP, 14)); 298 299 mcr |= GEN_MASK(dev->cli.count, I2C_MCR_LENGTH, 15); 300 301 return mcr; 302} 303 304/** 305 * setup_i2c_controller() - setup the controller 306 * @dev: private data of controller 307 */ 308static void setup_i2c_controller(struct nmk_i2c_dev *dev) 309{ 310 u32 brcr1, brcr2; 311 u32 i2c_clk, div; 312 313 writel(0x0, dev->virtbase + I2C_CR); 314 writel(0x0, dev->virtbase + I2C_HSMCR); 315 writel(0x0, dev->virtbase + I2C_TFTR); 316 writel(0x0, dev->virtbase + I2C_RFTR); 317 writel(0x0, dev->virtbase + I2C_DMAR); 318 319 /* 320 * set the slsu: 321 * 322 * slsu defines the data setup time after SCL clock 323 * stretching in terms of i2c clk cycles. The 324 * needed setup time for the three modes are 250ns, 325 * 100ns, 10ns repectively thus leading to the values 326 * of 14, 6, 2 for a 48 MHz i2c clk. 327 */ 328 writel(dev->cfg.slsu << 16, dev->virtbase + I2C_SCR); 329 330 i2c_clk = clk_get_rate(dev->clk); 331 332 /* fallback to std. mode if machine has not provided it */ 333 if (dev->cfg.clk_freq == 0) 334 dev->cfg.clk_freq = 100000; 335 336 /* 337 * The spec says, in case of std. mode the divider is 338 * 2 whereas it is 3 for fast and fastplus mode of 339 * operation. TODO - high speed support. 340 */ 341 div = (dev->cfg.clk_freq > 100000) ? 3 : 2; 342 343 /* 344 * generate the mask for baud rate counters. The controller 345 * has two baud rate counters. One is used for High speed 346 * operation, and the other is for std, fast mode, fast mode 347 * plus operation. Currently we do not supprt high speed mode 348 * so set brcr1 to 0. 349 */ 350 brcr1 = 0 << 16; 351 brcr2 = (i2c_clk/(dev->cfg.clk_freq * div)) & 0xffff; 352 353 /* set the baud rate counter register */ 354 writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR); 355 356 /* 357 * set the speed mode. Currently we support 358 * only standard and fast mode of operation 359 * TODO - support for fast mode plus (upto 1Mb/s) 360 * and high speed (up to 3.4 Mb/s) 361 */ 362 if (dev->cfg.sm > I2C_FREQ_MODE_FAST) { 363 dev_err(&dev->pdev->dev, "do not support this mode " 364 "defaulting to std. mode\n"); 365 brcr2 = i2c_clk/(100000 * 2) & 0xffff; 366 writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR); 367 writel(I2C_FREQ_MODE_STANDARD << 4, 368 dev->virtbase + I2C_CR); 369 } 370 writel(dev->cfg.sm << 4, dev->virtbase + I2C_CR); 371 372 /* set the Tx and Rx FIFO threshold */ 373 writel(dev->cfg.tft, dev->virtbase + I2C_TFTR); 374 writel(dev->cfg.rft, dev->virtbase + I2C_RFTR); 375} 376 377/** 378 * read_i2c() - Read from I2C client device 379 * @dev: private data of I2C Driver 380 * 381 * This function reads from i2c client device when controller is in 382 * master mode. There is a completion timeout. If there is no transfer 383 * before timeout error is returned. 384 */ 385static int read_i2c(struct nmk_i2c_dev *dev) 386{ 387 u32 status = 0; 388 u32 mcr; 389 u32 irq_mask = 0; 390 int timeout; 391 392 mcr = load_i2c_mcr_reg(dev); 393 writel(mcr, dev->virtbase + I2C_MCR); 394 395 /* load the current CR value */ 396 writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR, 397 dev->virtbase + I2C_CR); 398 399 /* enable the controller */ 400 i2c_set_bit(dev->virtbase + I2C_CR, I2C_CR_PE); 401 402 init_completion(&dev->xfer_complete); 403 404 /* enable interrupts by setting the mask */ 405 irq_mask = (I2C_IT_RXFNF | I2C_IT_RXFF | 406 I2C_IT_MAL | I2C_IT_BERR); 407 408 if (dev->stop) 409 irq_mask |= I2C_IT_MTD; 410 else 411 irq_mask |= I2C_IT_MTDWS; 412 413 irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask); 414 415 writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask, 416 dev->virtbase + I2C_IMSCR); 417 418 timeout = wait_for_completion_interruptible_timeout( 419 &dev->xfer_complete, msecs_to_jiffies(I2C_TIMEOUT_MS)); 420 421 if (timeout < 0) { 422 dev_err(&dev->pdev->dev, 423 "wait_for_completion_interruptible_timeout" 424 "returned %d waiting for event\n", timeout); 425 status = timeout; 426 } 427 428 if (timeout == 0) { 429 /* controler has timedout, re-init the h/w */ 430 dev_err(&dev->pdev->dev, "controller timed out, re-init h/w\n"); 431 (void) init_hw(dev); 432 status = -ETIMEDOUT; 433 } 434 435 return status; 436} 437 438/** 439 * write_i2c() - Write data to I2C client. 440 * @dev: private data of I2C Driver 441 * 442 * This function writes data to I2C client 443 */ 444static int write_i2c(struct nmk_i2c_dev *dev) 445{ 446 u32 status = 0; 447 u32 mcr; 448 u32 irq_mask = 0; 449 int timeout; 450 451 mcr = load_i2c_mcr_reg(dev); 452 453 writel(mcr, dev->virtbase + I2C_MCR); 454 455 /* load the current CR value */ 456 writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR, 457 dev->virtbase + I2C_CR); 458 459 /* enable the controller */ 460 i2c_set_bit(dev->virtbase + I2C_CR , I2C_CR_PE); 461 462 init_completion(&dev->xfer_complete); 463 464 /* enable interrupts by settings the masks */ 465 irq_mask = (I2C_IT_TXFNE | I2C_IT_TXFOVR | 466 I2C_IT_MAL | I2C_IT_BERR); 467 468 /* 469 * check if we want to transfer a single or multiple bytes, if so 470 * set the MTDWS bit (Master Transaction Done Without Stop) 471 * to start repeated start operation 472 */ 473 if (dev->stop) 474 irq_mask |= I2C_IT_MTD; 475 else 476 irq_mask |= I2C_IT_MTDWS; 477 478 irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask); 479 480 writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask, 481 dev->virtbase + I2C_IMSCR); 482 483 timeout = wait_for_completion_interruptible_timeout( 484 &dev->xfer_complete, msecs_to_jiffies(I2C_TIMEOUT_MS)); 485 486 if (timeout < 0) { 487 dev_err(&dev->pdev->dev, 488 "wait_for_completion_interruptible_timeout" 489 "returned %d waiting for event\n", timeout); 490 status = timeout; 491 } 492 493 if (timeout == 0) { 494 /* controler has timedout, re-init the h/w */ 495 dev_err(&dev->pdev->dev, "controller timed out, re-init h/w\n"); 496 (void) init_hw(dev); 497 status = -ETIMEDOUT; 498 } 499 500 return status; 501} 502 503/** 504 * nmk_i2c_xfer() - I2C transfer function used by kernel framework 505 * @i2c_adap - Adapter pointer to the controller 506 * @msgs[] - Pointer to data to be written. 507 * @num_msgs - Number of messages to be executed 508 * 509 * This is the function called by the generic kernel i2c_transfer() 510 * or i2c_smbus...() API calls. Note that this code is protected by the 511 * semaphore set in the kernel i2c_transfer() function. 512 * 513 * NOTE: 514 * READ TRANSFER : We impose a restriction of the first message to be the 515 * index message for any read transaction. 516 * - a no index is coded as '0', 517 * - 2byte big endian index is coded as '3' 518 * !!! msg[0].buf holds the actual index. 519 * This is compatible with generic messages of smbus emulator 520 * that send a one byte index. 521 * eg. a I2C transation to read 2 bytes from index 0 522 * idx = 0; 523 * msg[0].addr = client->addr; 524 * msg[0].flags = 0x0; 525 * msg[0].len = 1; 526 * msg[0].buf = &idx; 527 * 528 * msg[1].addr = client->addr; 529 * msg[1].flags = I2C_M_RD; 530 * msg[1].len = 2; 531 * msg[1].buf = rd_buff 532 * i2c_transfer(adap, msg, 2); 533 * 534 * WRITE TRANSFER : The I2C standard interface interprets all data as payload. 535 * If you want to emulate an SMBUS write transaction put the 536 * index as first byte(or first and second) in the payload. 537 * eg. a I2C transation to write 2 bytes from index 1 538 * wr_buff[0] = 0x1; 539 * wr_buff[1] = 0x23; 540 * wr_buff[2] = 0x46; 541 * msg[0].flags = 0x0; 542 * msg[0].len = 3; 543 * msg[0].buf = wr_buff; 544 * i2c_transfer(adap, msg, 1); 545 * 546 * To read or write a block of data (multiple bytes) using SMBUS emulation 547 * please use the i2c_smbus_read_i2c_block_data() 548 * or i2c_smbus_write_i2c_block_data() API 549 */ 550static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap, 551 struct i2c_msg msgs[], int num_msgs) 552{ 553 int status; 554 int i; 555 u32 cause; 556 struct nmk_i2c_dev *dev = i2c_get_adapdata(i2c_adap); 557 558 status = init_hw(dev); 559 if (status) 560 return status; 561 562 /* setup the i2c controller */ 563 setup_i2c_controller(dev); 564 565 for (i = 0; i < num_msgs; i++) { 566 if (unlikely(msgs[i].flags & I2C_M_TEN)) { 567 dev_err(&dev->pdev->dev, "10 bit addressing" 568 "not supported\n"); 569 return -EINVAL; 570 } 571 dev->cli.slave_adr = msgs[i].addr; 572 dev->cli.buffer = msgs[i].buf; 573 dev->cli.count = msgs[i].len; 574 dev->stop = (i < (num_msgs - 1)) ? 0 : 1; 575 dev->result = 0; 576 577 if (msgs[i].flags & I2C_M_RD) { 578 /* it is a read operation */ 579 dev->cli.operation = I2C_READ; 580 status = read_i2c(dev); 581 } else { 582 /* write operation */ 583 dev->cli.operation = I2C_WRITE; 584 status = write_i2c(dev); 585 } 586 if (status || (dev->result)) { 587 /* get the abort cause */ 588 cause = (readl(dev->virtbase + I2C_SR) >> 4) & 0x7; 589 dev_err(&dev->pdev->dev, "error during I2C" 590 "message xfer: %d\n", cause); 591 dev_err(&dev->pdev->dev, "%s\n", 592 cause >= ARRAY_SIZE(abort_causes) 593 ? "unknown reason" : abort_causes[cause]); 594 return status; 595 } 596 mdelay(1); 597 } 598 /* return the no. messages processed */ 599 if (status) 600 return status; 601 else 602 return num_msgs; 603} 604 605/** 606 * disable_interrupts() - disable the interrupts 607 * @dev: private data of controller 608 */ 609static int disable_interrupts(struct nmk_i2c_dev *dev, u32 irq) 610{ 611 irq = IRQ_MASK(irq); 612 writel(readl(dev->virtbase + I2C_IMSCR) & ~(I2C_CLEAR_ALL_INTS & irq), 613 dev->virtbase + I2C_IMSCR); 614 return 0; 615} 616 617/** 618 * i2c_irq_handler() - interrupt routine 619 * @irq: interrupt number 620 * @arg: data passed to the handler 621 * 622 * This is the interrupt handler for the i2c driver. Currently 623 * it handles the major interrupts like Rx & Tx FIFO management 624 * interrupts, master transaction interrupts, arbitration and 625 * bus error interrupts. The rest of the interrupts are treated as 626 * unhandled. 627 */ 628static irqreturn_t i2c_irq_handler(int irq, void *arg) 629{ 630 struct nmk_i2c_dev *dev = arg; 631 u32 tft, rft; 632 u32 count; 633 u32 misr; 634 u32 src = 0; 635 636 /* load Tx FIFO and Rx FIFO threshold values */ 637 tft = readl(dev->virtbase + I2C_TFTR); 638 rft = readl(dev->virtbase + I2C_RFTR); 639 640 /* read interrupt status register */ 641 misr = readl(dev->virtbase + I2C_MISR); 642 643 src = __ffs(misr); 644 switch ((1 << src)) { 645 646 /* Transmit FIFO nearly empty interrupt */ 647 case I2C_IT_TXFNE: 648 { 649 if (dev->cli.operation == I2C_READ) { 650 /* 651 * in read operation why do we care for writing? 652 * so disable the Transmit FIFO interrupt 653 */ 654 disable_interrupts(dev, I2C_IT_TXFNE); 655 } else { 656 for (count = (MAX_I2C_FIFO_THRESHOLD - tft - 2); 657 (count > 0) && 658 (dev->cli.count != 0); 659 count--) { 660 /* write to the Tx FIFO */ 661 writeb(*dev->cli.buffer, 662 dev->virtbase + I2C_TFR); 663 dev->cli.buffer++; 664 dev->cli.count--; 665 dev->cli.xfer_bytes++; 666 } 667 /* 668 * if done, close the transfer by disabling the 669 * corresponding TXFNE interrupt 670 */ 671 if (dev->cli.count == 0) 672 disable_interrupts(dev, I2C_IT_TXFNE); 673 } 674 } 675 break; 676 677 /* 678 * Rx FIFO nearly full interrupt. 679 * This is set when the numer of entries in Rx FIFO is 680 * greater or equal than the threshold value programmed 681 * in RFT 682 */ 683 case I2C_IT_RXFNF: 684 for (count = rft; count > 0; count--) { 685 /* Read the Rx FIFO */ 686 *dev->cli.buffer = readb(dev->virtbase + I2C_RFR); 687 dev->cli.buffer++; 688 } 689 dev->cli.count -= rft; 690 dev->cli.xfer_bytes += rft; 691 break; 692 693 /* Rx FIFO full */ 694 case I2C_IT_RXFF: 695 for (count = MAX_I2C_FIFO_THRESHOLD; count > 0; count--) { 696 *dev->cli.buffer = readb(dev->virtbase + I2C_RFR); 697 dev->cli.buffer++; 698 } 699 dev->cli.count -= MAX_I2C_FIFO_THRESHOLD; 700 dev->cli.xfer_bytes += MAX_I2C_FIFO_THRESHOLD; 701 break; 702 703 /* Master Transaction Done with/without stop */ 704 case I2C_IT_MTD: 705 case I2C_IT_MTDWS: 706 if (dev->cli.operation == I2C_READ) { 707 while (!(readl(dev->virtbase + I2C_RISR) 708 & I2C_IT_RXFE)) { 709 if (dev->cli.count == 0) 710 break; 711 *dev->cli.buffer = 712 readb(dev->virtbase + I2C_RFR); 713 dev->cli.buffer++; 714 dev->cli.count--; 715 dev->cli.xfer_bytes++; 716 } 717 } 718 719 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MTD); 720 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MTDWS); 721 722 disable_interrupts(dev, 723 (I2C_IT_TXFNE | I2C_IT_TXFE | I2C_IT_TXFF 724 | I2C_IT_TXFOVR | I2C_IT_RXFNF 725 | I2C_IT_RXFF | I2C_IT_RXFE)); 726 727 if (dev->cli.count) { 728 dev->result = -1; 729 dev_err(&dev->pdev->dev, "%lu bytes still remain to be" 730 "xfered\n", dev->cli.count); 731 (void) init_hw(dev); 732 } 733 complete(&dev->xfer_complete); 734 735 break; 736 737 /* Master Arbitration lost interrupt */ 738 case I2C_IT_MAL: 739 dev->result = -1; 740 (void) init_hw(dev); 741 742 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MAL); 743 complete(&dev->xfer_complete); 744 745 break; 746 747 /* 748 * Bus Error interrupt. 749 * This happens when an unexpected start/stop condition occurs 750 * during the transaction. 751 */ 752 case I2C_IT_BERR: 753 dev->result = -1; 754 /* get the status */ 755 if (((readl(dev->virtbase + I2C_SR) >> 2) & 0x3) == I2C_ABORT) 756 (void) init_hw(dev); 757 758 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_BERR); 759 complete(&dev->xfer_complete); 760 761 break; 762 763 /* 764 * Tx FIFO overrun interrupt. 765 * This is set when a write operation in Tx FIFO is performed and 766 * the Tx FIFO is full. 767 */ 768 case I2C_IT_TXFOVR: 769 dev->result = -1; 770 (void) init_hw(dev); 771 772 dev_err(&dev->pdev->dev, "Tx Fifo Over run\n"); 773 complete(&dev->xfer_complete); 774 775 break; 776 777 /* unhandled interrupts by this driver - TODO*/ 778 case I2C_IT_TXFE: 779 case I2C_IT_TXFF: 780 case I2C_IT_RXFE: 781 case I2C_IT_RFSR: 782 case I2C_IT_RFSE: 783 case I2C_IT_WTSR: 784 case I2C_IT_STD: 785 dev_err(&dev->pdev->dev, "unhandled Interrupt\n"); 786 break; 787 default: 788 dev_err(&dev->pdev->dev, "spurious Interrupt..\n"); 789 break; 790 } 791 792 return IRQ_HANDLED; 793} 794 795static unsigned int nmk_i2c_functionality(struct i2c_adapter *adap) 796{ 797 return I2C_FUNC_I2C 798 | I2C_FUNC_SMBUS_BYTE_DATA 799 | I2C_FUNC_SMBUS_WORD_DATA 800 | I2C_FUNC_SMBUS_I2C_BLOCK; 801} 802 803static const struct i2c_algorithm nmk_i2c_algo = { 804 .master_xfer = nmk_i2c_xfer, 805 .functionality = nmk_i2c_functionality 806}; 807 808static int __devinit nmk_i2c_probe(struct platform_device *pdev) 809{ 810 int ret = 0; 811 struct resource *res; 812 struct nmk_i2c_controller *pdata = 813 pdev->dev.platform_data; 814 struct nmk_i2c_dev *dev; 815 struct i2c_adapter *adap; 816 817 dev = kzalloc(sizeof(struct nmk_i2c_dev), GFP_KERNEL); 818 if (!dev) { 819 dev_err(&pdev->dev, "cannot allocate memory\n"); 820 ret = -ENOMEM; 821 goto err_no_mem; 822 } 823 824 dev->pdev = pdev; 825 platform_set_drvdata(pdev, dev); 826 827 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 828 if (!res) { 829 ret = -ENOENT; 830 goto err_no_resource; 831 } 832 833 if (request_mem_region(res->start, resource_size(res), 834 DRIVER_NAME "I/O region") == NULL) { 835 ret = -EBUSY; 836 goto err_no_region; 837 } 838 839 dev->virtbase = ioremap(res->start, resource_size(res)); 840 if (!dev->virtbase) { 841 ret = -ENOMEM; 842 goto err_no_ioremap; 843 } 844 845 dev->irq = platform_get_irq(pdev, 0); 846 ret = request_irq(dev->irq, i2c_irq_handler, IRQF_DISABLED, 847 DRIVER_NAME, dev); 848 if (ret) { 849 dev_err(&pdev->dev, "cannot claim the irq %d\n", dev->irq); 850 goto err_irq; 851 } 852 853 dev->clk = clk_get(&pdev->dev, NULL); 854 if (IS_ERR(dev->clk)) { 855 dev_err(&pdev->dev, "could not get i2c clock\n"); 856 ret = PTR_ERR(dev->clk); 857 goto err_no_clk; 858 } 859 860 clk_enable(dev->clk); 861 862 adap = &dev->adap; 863 adap->dev.parent = &pdev->dev; 864 adap->owner = THIS_MODULE; 865 adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD; 866 adap->algo = &nmk_i2c_algo; 867 868 /* fetch the controller id */ 869 adap->nr = pdev->id; 870 871 /* fetch the controller configuration from machine */ 872 dev->cfg.clk_freq = pdata->clk_freq; 873 dev->cfg.slsu = pdata->slsu; 874 dev->cfg.tft = pdata->tft; 875 dev->cfg.rft = pdata->rft; 876 dev->cfg.sm = pdata->sm; 877 878 i2c_set_adapdata(adap, dev); 879 880 ret = init_hw(dev); 881 if (ret != 0) { 882 dev_err(&pdev->dev, "error in initializing i2c hardware\n"); 883 goto err_init_hw; 884 } 885 886 dev_dbg(&pdev->dev, "initialize I2C%d bus on virtual " 887 "base %p\n", pdev->id, dev->virtbase); 888 889 ret = i2c_add_numbered_adapter(adap); 890 if (ret) { 891 dev_err(&pdev->dev, "failed to add adapter\n"); 892 goto err_add_adap; 893 } 894 895 return 0; 896 897 err_init_hw: 898 clk_disable(dev->clk); 899 err_add_adap: 900 clk_put(dev->clk); 901 err_no_clk: 902 free_irq(dev->irq, dev); 903 err_irq: 904 iounmap(dev->virtbase); 905 err_no_ioremap: 906 release_mem_region(res->start, resource_size(res)); 907 err_no_region: 908 platform_set_drvdata(pdev, NULL); 909 err_no_resource: 910 kfree(dev); 911 err_no_mem: 912 913 return ret; 914} 915 916static int __devexit nmk_i2c_remove(struct platform_device *pdev) 917{ 918 struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 919 struct nmk_i2c_dev *dev = platform_get_drvdata(pdev); 920 921 i2c_del_adapter(&dev->adap); 922 flush_i2c_fifo(dev); 923 disable_all_interrupts(dev); 924 clear_all_interrupts(dev); 925 /* disable the controller */ 926 i2c_clr_bit(dev->virtbase + I2C_CR, I2C_CR_PE); 927 free_irq(dev->irq, dev); 928 iounmap(dev->virtbase); 929 if (res) 930 release_mem_region(res->start, resource_size(res)); 931 clk_disable(dev->clk); 932 clk_put(dev->clk); 933 platform_set_drvdata(pdev, NULL); 934 kfree(dev); 935 936 return 0; 937} 938 939static struct platform_driver nmk_i2c_driver = { 940 .driver = { 941 .owner = THIS_MODULE, 942 .name = DRIVER_NAME, 943 }, 944 .probe = nmk_i2c_probe, 945 .remove = __devexit_p(nmk_i2c_remove), 946}; 947 948static int __init nmk_i2c_init(void) 949{ 950 return platform_driver_register(&nmk_i2c_driver); 951} 952 953static void __exit nmk_i2c_exit(void) 954{ 955 platform_driver_unregister(&nmk_i2c_driver); 956} 957 958subsys_initcall(nmk_i2c_init); 959module_exit(nmk_i2c_exit); 960 961MODULE_AUTHOR("Sachin Verma, Srinidhi KASAGAR"); 962MODULE_DESCRIPTION("Nomadik/Ux500 I2C driver"); 963MODULE_LICENSE("GPL"); 964MODULE_ALIAS("platform:" DRIVER_NAME); 965