1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * SuperH Mobile I2C Controller 4 * 5 * Copyright (C) 2014-19 Wolfram Sang <wsa@sang-engineering.com> 6 * Copyright (C) 2008 Magnus Damm 7 * 8 * Portions of the code based on out-of-tree driver i2c-sh7343.c 9 * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com> 10 */ 11 12 #include <linux/clk.h> 13 #include <linux/delay.h> 14 #include <linux/dmaengine.h> 15 #include <linux/dma-mapping.h> 16 #include <linux/err.h> 17 #include <linux/i2c.h> 18 #include <linux/init.h> 19 #include <linux/interrupt.h> 20 #include <linux/io.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/of_device.h> 24 #include <linux/platform_device.h> 25 #include <linux/pm_runtime.h> 26 #include <linux/slab.h> 27 28 /* Transmit operation: */ 29 /* */ 30 /* 0 byte transmit */ 31 /* BUS: S A8 ACK P(*) */ 32 /* IRQ: DTE WAIT */ 33 /* ICIC: */ 34 /* ICCR: 0x94 0x90 */ 35 /* ICDR: A8 */ 36 /* */ 37 /* 1 byte transmit */ 38 /* BUS: S A8 ACK D8(1) ACK P(*) */ 39 /* IRQ: DTE WAIT WAIT */ 40 /* ICIC: -DTE */ 41 /* ICCR: 0x94 0x90 */ 42 /* ICDR: A8 D8(1) */ 43 /* */ 44 /* 2 byte transmit */ 45 /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P(*) */ 46 /* IRQ: DTE WAIT WAIT WAIT */ 47 /* ICIC: -DTE */ 48 /* ICCR: 0x94 0x90 */ 49 /* ICDR: A8 D8(1) D8(2) */ 50 /* */ 51 /* 3 bytes or more, +---------+ gets repeated */ 52 /* */ 53 /* */ 54 /* Receive operation: */ 55 /* */ 56 /* 0 byte receive - not supported since slave may hold SDA low */ 57 /* */ 58 /* 1 byte receive [TX] | [RX] */ 59 /* BUS: S A8 ACK | D8(1) ACK P(*) */ 60 /* IRQ: DTE WAIT | WAIT DTE */ 61 /* ICIC: -DTE | +DTE */ 62 /* ICCR: 0x94 0x81 | 0xc0 */ 63 /* ICDR: A8 | D8(1) */ 64 /* */ 65 /* 2 byte receive [TX]| [RX] */ 66 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P(*) */ 67 /* IRQ: DTE WAIT | WAIT WAIT DTE */ 68 /* ICIC: -DTE | +DTE */ 69 /* ICCR: 0x94 0x81 | 0xc0 */ 70 /* ICDR: A8 | D8(1) D8(2) */ 71 /* */ 72 /* 3 byte receive [TX] | [RX] (*) */ 73 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */ 74 /* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */ 75 /* ICIC: -DTE | +DTE */ 76 /* ICCR: 0x94 0x81 | 0xc0 */ 77 /* ICDR: A8 | D8(1) D8(2) D8(3) */ 78 /* */ 79 /* 4 bytes or more, this part is repeated +---------+ */ 80 /* */ 81 /* */ 82 /* Interrupt order and BUSY flag */ 83 /* ___ _ */ 84 /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */ 85 /* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */ 86 /* */ 87 /* S D7 D6 D5 D4 D3 D2 D1 D0 P(*) */ 88 /* ___ */ 89 /* WAIT IRQ ________________________________/ \___________ */ 90 /* TACK IRQ ____________________________________/ \_______ */ 91 /* DTE IRQ __________________________________________/ \_ */ 92 /* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */ 93 /* _______________________________________________ */ 94 /* BUSY __/ \_ */ 95 /* */ 96 /* (*) The STOP condition is only sent by the master at the end of the last */ 97 /* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */ 98 /* only cleared after the STOP condition, so, between messages we have to */ 99 /* poll for the DTE bit. */ 100 /* */ 101 102 enum sh_mobile_i2c_op { 103 OP_START = 0, 104 OP_TX_FIRST, 105 OP_TX, 106 OP_TX_STOP, 107 OP_TX_TO_RX, 108 OP_RX, 109 OP_RX_STOP, 110 OP_RX_STOP_DATA, 111 }; 112 113 struct sh_mobile_i2c_data { 114 struct device *dev; 115 void __iomem *reg; 116 struct i2c_adapter adap; 117 unsigned long bus_speed; 118 unsigned int clks_per_count; 119 struct clk *clk; 120 u_int8_t icic; 121 u_int8_t flags; 122 u_int16_t iccl; 123 u_int16_t icch; 124 125 spinlock_t lock; 126 wait_queue_head_t wait; 127 struct i2c_msg *msg; 128 int pos; 129 int sr; 130 bool send_stop; 131 bool stop_after_dma; 132 133 struct resource *res; 134 struct dma_chan *dma_tx; 135 struct dma_chan *dma_rx; 136 struct scatterlist sg; 137 enum dma_data_direction dma_direction; 138 u8 *dma_buf; 139 }; 140 141 struct sh_mobile_dt_config { 142 int clks_per_count; 143 int (*setup)(struct sh_mobile_i2c_data *pd); 144 }; 145 146 #define IIC_FLAG_HAS_ICIC67 (1 << 0) 147 148 #define STANDARD_MODE 100000 149 #define FAST_MODE 400000 150 151 /* Register offsets */ 152 #define ICDR 0x00 153 #define ICCR 0x04 154 #define ICSR 0x08 155 #define ICIC 0x0c 156 #define ICCL 0x10 157 #define ICCH 0x14 158 #define ICSTART 0x70 159 160 /* Register bits */ 161 #define ICCR_ICE 0x80 162 #define ICCR_RACK 0x40 163 #define ICCR_TRS 0x10 164 #define ICCR_BBSY 0x04 165 #define ICCR_SCP 0x01 166 167 #define ICSR_SCLM 0x80 168 #define ICSR_SDAM 0x40 169 #define SW_DONE 0x20 170 #define ICSR_BUSY 0x10 171 #define ICSR_AL 0x08 172 #define ICSR_TACK 0x04 173 #define ICSR_WAIT 0x02 174 #define ICSR_DTE 0x01 175 176 #define ICIC_ICCLB8 0x80 177 #define ICIC_ICCHB8 0x40 178 #define ICIC_TDMAE 0x20 179 #define ICIC_RDMAE 0x10 180 #define ICIC_ALE 0x08 181 #define ICIC_TACKE 0x04 182 #define ICIC_WAITE 0x02 183 #define ICIC_DTEE 0x01 184 185 #define ICSTART_ICSTART 0x10 186 187 static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data) 188 { 189 if (offs == ICIC) 190 data |= pd->icic; 191 192 iowrite8(data, pd->reg + offs); 193 } 194 195 static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs) 196 { 197 return ioread8(pd->reg + offs); 198 } 199 200 static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs, 201 unsigned char set, unsigned char clr) 202 { 203 iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr); 204 } 205 206 static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf) 207 { 208 /* 209 * Conditional expression: 210 * ICCL >= COUNT_CLK * (tLOW + tf) 211 * 212 * SH-Mobile IIC hardware starts counting the LOW period of 213 * the SCL signal (tLOW) as soon as it pulls the SCL line. 214 * In order to meet the tLOW timing spec, we need to take into 215 * account the fall time of SCL signal (tf). Default tf value 216 * should be 0.3 us, for safety. 217 */ 218 return (((count_khz * (tLOW + tf)) + 5000) / 10000); 219 } 220 221 static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf) 222 { 223 /* 224 * Conditional expression: 225 * ICCH >= COUNT_CLK * (tHIGH + tf) 226 * 227 * SH-Mobile IIC hardware is aware of SCL transition period 'tr', 228 * and can ignore it. SH-Mobile IIC controller starts counting 229 * the HIGH period of the SCL signal (tHIGH) after the SCL input 230 * voltage increases at VIH. 231 * 232 * Afterward it turned out calculating ICCH using only tHIGH spec 233 * will result in violation of the tHD;STA timing spec. We need 234 * to take into account the fall time of SDA signal (tf) at START 235 * condition, in order to meet both tHIGH and tHD;STA specs. 236 */ 237 return (((count_khz * (tHIGH + tf)) + 5000) / 10000); 238 } 239 240 static int sh_mobile_i2c_check_timing(struct sh_mobile_i2c_data *pd) 241 { 242 u16 max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff; 243 244 if (pd->iccl > max_val || pd->icch > max_val) { 245 dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n", 246 pd->iccl, pd->icch); 247 return -EINVAL; 248 } 249 250 /* one more bit of ICCL in ICIC */ 251 if (pd->iccl & 0x100) 252 pd->icic |= ICIC_ICCLB8; 253 else 254 pd->icic &= ~ICIC_ICCLB8; 255 256 /* one more bit of ICCH in ICIC */ 257 if (pd->icch & 0x100) 258 pd->icic |= ICIC_ICCHB8; 259 else 260 pd->icic &= ~ICIC_ICCHB8; 261 262 dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch); 263 return 0; 264 } 265 266 static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd) 267 { 268 unsigned long i2c_clk_khz; 269 u32 tHIGH, tLOW, tf; 270 271 i2c_clk_khz = clk_get_rate(pd->clk) / 1000 / pd->clks_per_count; 272 273 if (pd->bus_speed == STANDARD_MODE) { 274 tLOW = 47; /* tLOW = 4.7 us */ 275 tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */ 276 tf = 3; /* tf = 0.3 us */ 277 } else if (pd->bus_speed == FAST_MODE) { 278 tLOW = 13; /* tLOW = 1.3 us */ 279 tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */ 280 tf = 3; /* tf = 0.3 us */ 281 } else { 282 dev_err(pd->dev, "unrecognized bus speed %lu Hz\n", 283 pd->bus_speed); 284 return -EINVAL; 285 } 286 287 pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf); 288 pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf); 289 290 return sh_mobile_i2c_check_timing(pd); 291 } 292 293 static int sh_mobile_i2c_v2_init(struct sh_mobile_i2c_data *pd) 294 { 295 unsigned long clks_per_cycle; 296 297 /* L = 5, H = 4, L + H = 9 */ 298 clks_per_cycle = clk_get_rate(pd->clk) / pd->bus_speed; 299 pd->iccl = DIV_ROUND_UP(clks_per_cycle * 5 / 9 - 1, pd->clks_per_count); 300 pd->icch = DIV_ROUND_UP(clks_per_cycle * 4 / 9 - 5, pd->clks_per_count); 301 302 return sh_mobile_i2c_check_timing(pd); 303 } 304 305 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, enum sh_mobile_i2c_op op) 306 { 307 unsigned char ret = 0; 308 unsigned long flags; 309 310 dev_dbg(pd->dev, "op %d\n", op); 311 312 spin_lock_irqsave(&pd->lock, flags); 313 314 switch (op) { 315 case OP_START: /* issue start and trigger DTE interrupt */ 316 iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY); 317 break; 318 case OP_TX_FIRST: /* disable DTE interrupt and write client address */ 319 iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 320 iic_wr(pd, ICDR, i2c_8bit_addr_from_msg(pd->msg)); 321 break; 322 case OP_TX: /* write data */ 323 iic_wr(pd, ICDR, pd->msg->buf[pd->pos]); 324 break; 325 case OP_TX_STOP: /* issue a stop (or rep_start) */ 326 iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS 327 : ICCR_ICE | ICCR_TRS | ICCR_BBSY); 328 break; 329 case OP_TX_TO_RX: /* select read mode */ 330 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP); 331 break; 332 case OP_RX: /* just read data */ 333 ret = iic_rd(pd, ICDR); 334 break; 335 case OP_RX_STOP: /* enable DTE interrupt, issue stop */ 336 iic_wr(pd, ICIC, 337 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 338 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK); 339 break; 340 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */ 341 iic_wr(pd, ICIC, 342 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 343 ret = iic_rd(pd, ICDR); 344 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK); 345 break; 346 } 347 348 spin_unlock_irqrestore(&pd->lock, flags); 349 350 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret); 351 return ret; 352 } 353 354 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd) 355 { 356 if (pd->pos == pd->msg->len) { 357 i2c_op(pd, OP_TX_STOP); 358 return 1; 359 } 360 361 if (pd->pos == -1) 362 i2c_op(pd, OP_TX_FIRST); 363 else 364 i2c_op(pd, OP_TX); 365 366 pd->pos++; 367 return 0; 368 } 369 370 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd) 371 { 372 unsigned char data; 373 int real_pos; 374 375 /* switch from TX (address) to RX (data) adds two interrupts */ 376 real_pos = pd->pos - 2; 377 378 if (pd->pos == -1) { 379 i2c_op(pd, OP_TX_FIRST); 380 } else if (pd->pos == 0) { 381 i2c_op(pd, OP_TX_TO_RX); 382 } else if (pd->pos == pd->msg->len) { 383 if (pd->stop_after_dma) { 384 /* Simulate PIO end condition after DMA transfer */ 385 i2c_op(pd, OP_RX_STOP); 386 pd->pos++; 387 goto done; 388 } 389 390 if (real_pos < 0) 391 i2c_op(pd, OP_RX_STOP); 392 else 393 data = i2c_op(pd, OP_RX_STOP_DATA); 394 } else if (real_pos >= 0) { 395 data = i2c_op(pd, OP_RX); 396 } 397 398 if (real_pos >= 0) 399 pd->msg->buf[real_pos] = data; 400 done: 401 pd->pos++; 402 return pd->pos == (pd->msg->len + 2); 403 } 404 405 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) 406 { 407 struct sh_mobile_i2c_data *pd = dev_id; 408 unsigned char sr; 409 int wakeup = 0; 410 411 sr = iic_rd(pd, ICSR); 412 pd->sr |= sr; /* remember state */ 413 414 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr, 415 (pd->msg->flags & I2C_M_RD) ? "read" : "write", 416 pd->pos, pd->msg->len); 417 418 /* Kick off TxDMA after preface was done */ 419 if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0) 420 iic_set_clr(pd, ICIC, ICIC_TDMAE, 0); 421 else if (sr & (ICSR_AL | ICSR_TACK)) 422 /* don't interrupt transaction - continue to issue stop */ 423 iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK)); 424 else if (pd->msg->flags & I2C_M_RD) 425 wakeup = sh_mobile_i2c_isr_rx(pd); 426 else 427 wakeup = sh_mobile_i2c_isr_tx(pd); 428 429 /* Kick off RxDMA after preface was done */ 430 if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1) 431 iic_set_clr(pd, ICIC, ICIC_RDMAE, 0); 432 433 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */ 434 iic_wr(pd, ICSR, sr & ~ICSR_WAIT); 435 436 if (wakeup) { 437 pd->sr |= SW_DONE; 438 wake_up(&pd->wait); 439 } 440 441 /* defeat write posting to avoid spurious WAIT interrupts */ 442 iic_rd(pd, ICSR); 443 444 return IRQ_HANDLED; 445 } 446 447 static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd) 448 { 449 struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE 450 ? pd->dma_rx : pd->dma_tx; 451 452 dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg), 453 pd->msg->len, pd->dma_direction); 454 455 pd->dma_direction = DMA_NONE; 456 } 457 458 static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd) 459 { 460 if (pd->dma_direction == DMA_NONE) 461 return; 462 else if (pd->dma_direction == DMA_FROM_DEVICE) 463 dmaengine_terminate_all(pd->dma_rx); 464 else if (pd->dma_direction == DMA_TO_DEVICE) 465 dmaengine_terminate_all(pd->dma_tx); 466 467 sh_mobile_i2c_dma_unmap(pd); 468 } 469 470 static void sh_mobile_i2c_dma_callback(void *data) 471 { 472 struct sh_mobile_i2c_data *pd = data; 473 474 sh_mobile_i2c_dma_unmap(pd); 475 pd->pos = pd->msg->len; 476 pd->stop_after_dma = true; 477 478 iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE); 479 } 480 481 static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev, 482 enum dma_transfer_direction dir, dma_addr_t port_addr) 483 { 484 struct dma_chan *chan; 485 struct dma_slave_config cfg; 486 char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx"; 487 int ret; 488 489 chan = dma_request_slave_channel_reason(dev, chan_name); 490 if (IS_ERR(chan)) { 491 dev_dbg(dev, "request_channel failed for %s (%ld)\n", chan_name, 492 PTR_ERR(chan)); 493 return chan; 494 } 495 496 memset(&cfg, 0, sizeof(cfg)); 497 cfg.direction = dir; 498 if (dir == DMA_MEM_TO_DEV) { 499 cfg.dst_addr = port_addr; 500 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 501 } else { 502 cfg.src_addr = port_addr; 503 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 504 } 505 506 ret = dmaengine_slave_config(chan, &cfg); 507 if (ret) { 508 dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret); 509 dma_release_channel(chan); 510 return ERR_PTR(ret); 511 } 512 513 dev_dbg(dev, "got DMA channel for %s\n", chan_name); 514 return chan; 515 } 516 517 static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd) 518 { 519 bool read = pd->msg->flags & I2C_M_RD; 520 enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE; 521 struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx; 522 struct dma_async_tx_descriptor *txdesc; 523 dma_addr_t dma_addr; 524 dma_cookie_t cookie; 525 526 if (PTR_ERR(chan) == -EPROBE_DEFER) { 527 if (read) 528 chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM, 529 pd->res->start + ICDR); 530 else 531 chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV, 532 pd->res->start + ICDR); 533 } 534 535 if (IS_ERR(chan)) 536 return; 537 538 dma_addr = dma_map_single(chan->device->dev, pd->dma_buf, pd->msg->len, dir); 539 if (dma_mapping_error(chan->device->dev, dma_addr)) { 540 dev_dbg(pd->dev, "dma map failed, using PIO\n"); 541 return; 542 } 543 544 sg_dma_len(&pd->sg) = pd->msg->len; 545 sg_dma_address(&pd->sg) = dma_addr; 546 547 pd->dma_direction = dir; 548 549 txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1, 550 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV, 551 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 552 if (!txdesc) { 553 dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n"); 554 sh_mobile_i2c_cleanup_dma(pd); 555 return; 556 } 557 558 txdesc->callback = sh_mobile_i2c_dma_callback; 559 txdesc->callback_param = pd; 560 561 cookie = dmaengine_submit(txdesc); 562 if (dma_submit_error(cookie)) { 563 dev_dbg(pd->dev, "submitting dma failed, using PIO\n"); 564 sh_mobile_i2c_cleanup_dma(pd); 565 return; 566 } 567 568 dma_async_issue_pending(chan); 569 } 570 571 static void start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg, 572 bool do_init) 573 { 574 if (do_init) { 575 /* Initialize channel registers */ 576 iic_wr(pd, ICCR, ICCR_SCP); 577 578 /* Enable channel and configure rx ack */ 579 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP); 580 581 /* Set the clock */ 582 iic_wr(pd, ICCL, pd->iccl & 0xff); 583 iic_wr(pd, ICCH, pd->icch & 0xff); 584 } 585 586 pd->msg = usr_msg; 587 pd->pos = -1; 588 pd->sr = 0; 589 590 pd->dma_buf = i2c_get_dma_safe_msg_buf(pd->msg, 8); 591 if (pd->dma_buf) 592 sh_mobile_i2c_xfer_dma(pd); 593 594 /* Enable all interrupts to begin with */ 595 iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 596 } 597 598 static int poll_dte(struct sh_mobile_i2c_data *pd) 599 { 600 int i; 601 602 for (i = 1000; i; i--) { 603 u_int8_t val = iic_rd(pd, ICSR); 604 605 if (val & ICSR_DTE) 606 break; 607 608 if (val & ICSR_TACK) 609 return -ENXIO; 610 611 udelay(10); 612 } 613 614 return i ? 0 : -ETIMEDOUT; 615 } 616 617 static int poll_busy(struct sh_mobile_i2c_data *pd) 618 { 619 int i; 620 621 for (i = 1000; i; i--) { 622 u_int8_t val = iic_rd(pd, ICSR); 623 624 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr); 625 626 /* the interrupt handler may wake us up before the 627 * transfer is finished, so poll the hardware 628 * until we're done. 629 */ 630 if (!(val & ICSR_BUSY)) { 631 /* handle missing acknowledge and arbitration lost */ 632 val |= pd->sr; 633 if (val & ICSR_TACK) 634 return -ENXIO; 635 if (val & ICSR_AL) 636 return -EAGAIN; 637 break; 638 } 639 640 udelay(10); 641 } 642 643 return i ? 0 : -ETIMEDOUT; 644 } 645 646 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, 647 struct i2c_msg *msgs, 648 int num) 649 { 650 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter); 651 struct i2c_msg *msg; 652 int err = 0; 653 int i; 654 long timeout; 655 656 /* Wake up device and enable clock */ 657 pm_runtime_get_sync(pd->dev); 658 659 /* Process all messages */ 660 for (i = 0; i < num; i++) { 661 bool do_start = pd->send_stop || !i; 662 msg = &msgs[i]; 663 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP; 664 pd->stop_after_dma = false; 665 666 start_ch(pd, msg, do_start); 667 668 if (do_start) 669 i2c_op(pd, OP_START); 670 671 /* The interrupt handler takes care of the rest... */ 672 timeout = wait_event_timeout(pd->wait, 673 pd->sr & (ICSR_TACK | SW_DONE), 674 adapter->timeout); 675 676 /* 'stop_after_dma' tells if DMA transfer was complete */ 677 i2c_put_dma_safe_msg_buf(pd->dma_buf, pd->msg, pd->stop_after_dma); 678 679 if (!timeout) { 680 dev_err(pd->dev, "Transfer request timed out\n"); 681 if (pd->dma_direction != DMA_NONE) 682 sh_mobile_i2c_cleanup_dma(pd); 683 684 err = -ETIMEDOUT; 685 break; 686 } 687 688 if (pd->send_stop) 689 err = poll_busy(pd); 690 else 691 err = poll_dte(pd); 692 if (err < 0) 693 break; 694 } 695 696 /* Disable channel */ 697 iic_wr(pd, ICCR, ICCR_SCP); 698 699 /* Disable clock and mark device as idle */ 700 pm_runtime_put_sync(pd->dev); 701 702 return err ?: num; 703 } 704 705 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter) 706 { 707 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; 708 } 709 710 static const struct i2c_algorithm sh_mobile_i2c_algorithm = { 711 .functionality = sh_mobile_i2c_func, 712 .master_xfer = sh_mobile_i2c_xfer, 713 }; 714 715 static const struct i2c_adapter_quirks sh_mobile_i2c_quirks = { 716 .flags = I2C_AQ_NO_ZERO_LEN_READ, 717 }; 718 719 /* 720 * r8a7740 has an errata regarding I2C I/O pad reset needing this workaround. 721 */ 722 static int sh_mobile_i2c_r8a7740_workaround(struct sh_mobile_i2c_data *pd) 723 { 724 iic_set_clr(pd, ICCR, ICCR_ICE, 0); 725 iic_rd(pd, ICCR); /* dummy read */ 726 727 iic_set_clr(pd, ICSTART, ICSTART_ICSTART, 0); 728 iic_rd(pd, ICSTART); /* dummy read */ 729 730 udelay(10); 731 732 iic_wr(pd, ICCR, ICCR_SCP); 733 iic_wr(pd, ICSTART, 0); 734 735 udelay(10); 736 737 iic_wr(pd, ICCR, ICCR_TRS); 738 udelay(10); 739 iic_wr(pd, ICCR, 0); 740 udelay(10); 741 iic_wr(pd, ICCR, ICCR_TRS); 742 udelay(10); 743 744 return sh_mobile_i2c_init(pd); 745 } 746 747 static const struct sh_mobile_dt_config default_dt_config = { 748 .clks_per_count = 1, 749 .setup = sh_mobile_i2c_init, 750 }; 751 752 static const struct sh_mobile_dt_config fast_clock_dt_config = { 753 .clks_per_count = 2, 754 .setup = sh_mobile_i2c_init, 755 }; 756 757 static const struct sh_mobile_dt_config v2_freq_calc_dt_config = { 758 .clks_per_count = 2, 759 .setup = sh_mobile_i2c_v2_init, 760 }; 761 762 static const struct sh_mobile_dt_config r8a7740_dt_config = { 763 .clks_per_count = 1, 764 .setup = sh_mobile_i2c_r8a7740_workaround, 765 }; 766 767 static const struct of_device_id sh_mobile_i2c_dt_ids[] = { 768 { .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config }, 769 { .compatible = "renesas,iic-r8a7740", .data = &r8a7740_dt_config }, 770 { .compatible = "renesas,iic-r8a774c0", .data = &fast_clock_dt_config }, 771 { .compatible = "renesas,iic-r8a7790", .data = &v2_freq_calc_dt_config }, 772 { .compatible = "renesas,iic-r8a7791", .data = &v2_freq_calc_dt_config }, 773 { .compatible = "renesas,iic-r8a7792", .data = &v2_freq_calc_dt_config }, 774 { .compatible = "renesas,iic-r8a7793", .data = &v2_freq_calc_dt_config }, 775 { .compatible = "renesas,iic-r8a7794", .data = &v2_freq_calc_dt_config }, 776 { .compatible = "renesas,iic-r8a7795", .data = &v2_freq_calc_dt_config }, 777 { .compatible = "renesas,iic-r8a77990", .data = &v2_freq_calc_dt_config }, 778 { .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config }, 779 { .compatible = "renesas,rcar-gen2-iic", .data = &v2_freq_calc_dt_config }, 780 { .compatible = "renesas,rcar-gen3-iic", .data = &v2_freq_calc_dt_config }, 781 { .compatible = "renesas,rmobile-iic", .data = &default_dt_config }, 782 {}, 783 }; 784 MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids); 785 786 static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd) 787 { 788 if (!IS_ERR(pd->dma_tx)) { 789 dma_release_channel(pd->dma_tx); 790 pd->dma_tx = ERR_PTR(-EPROBE_DEFER); 791 } 792 793 if (!IS_ERR(pd->dma_rx)) { 794 dma_release_channel(pd->dma_rx); 795 pd->dma_rx = ERR_PTR(-EPROBE_DEFER); 796 } 797 } 798 799 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd) 800 { 801 struct resource *res; 802 resource_size_t n; 803 int k = 0, ret; 804 805 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) { 806 for (n = res->start; n <= res->end; n++) { 807 ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr, 808 0, dev_name(&dev->dev), pd); 809 if (ret) { 810 dev_err(&dev->dev, "cannot request IRQ %pa\n", &n); 811 return ret; 812 } 813 } 814 k++; 815 } 816 817 return k > 0 ? 0 : -ENOENT; 818 } 819 820 static int sh_mobile_i2c_probe(struct platform_device *dev) 821 { 822 struct sh_mobile_i2c_data *pd; 823 struct i2c_adapter *adap; 824 struct resource *res; 825 const struct sh_mobile_dt_config *config; 826 int ret; 827 u32 bus_speed; 828 829 pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL); 830 if (!pd) 831 return -ENOMEM; 832 833 pd->clk = devm_clk_get(&dev->dev, NULL); 834 if (IS_ERR(pd->clk)) { 835 dev_err(&dev->dev, "cannot get clock\n"); 836 return PTR_ERR(pd->clk); 837 } 838 839 ret = sh_mobile_i2c_hook_irqs(dev, pd); 840 if (ret) 841 return ret; 842 843 pd->dev = &dev->dev; 844 platform_set_drvdata(dev, pd); 845 846 res = platform_get_resource(dev, IORESOURCE_MEM, 0); 847 848 pd->res = res; 849 pd->reg = devm_ioremap_resource(&dev->dev, res); 850 if (IS_ERR(pd->reg)) 851 return PTR_ERR(pd->reg); 852 853 ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed); 854 pd->bus_speed = (ret || !bus_speed) ? STANDARD_MODE : bus_speed; 855 pd->clks_per_count = 1; 856 857 /* Newer variants come with two new bits in ICIC */ 858 if (resource_size(res) > 0x17) 859 pd->flags |= IIC_FLAG_HAS_ICIC67; 860 861 pm_runtime_enable(&dev->dev); 862 pm_runtime_get_sync(&dev->dev); 863 864 config = of_device_get_match_data(&dev->dev); 865 if (config) { 866 pd->clks_per_count = config->clks_per_count; 867 ret = config->setup(pd); 868 } else { 869 ret = sh_mobile_i2c_init(pd); 870 } 871 872 pm_runtime_put_sync(&dev->dev); 873 if (ret) 874 return ret; 875 876 /* Init DMA */ 877 sg_init_table(&pd->sg, 1); 878 pd->dma_direction = DMA_NONE; 879 pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER); 880 881 /* setup the private data */ 882 adap = &pd->adap; 883 i2c_set_adapdata(adap, pd); 884 885 adap->owner = THIS_MODULE; 886 adap->algo = &sh_mobile_i2c_algorithm; 887 adap->quirks = &sh_mobile_i2c_quirks; 888 adap->dev.parent = &dev->dev; 889 adap->retries = 5; 890 adap->nr = dev->id; 891 adap->dev.of_node = dev->dev.of_node; 892 893 strlcpy(adap->name, dev->name, sizeof(adap->name)); 894 895 spin_lock_init(&pd->lock); 896 init_waitqueue_head(&pd->wait); 897 898 ret = i2c_add_numbered_adapter(adap); 899 if (ret < 0) { 900 sh_mobile_i2c_release_dma(pd); 901 return ret; 902 } 903 904 dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed); 905 906 return 0; 907 } 908 909 static int sh_mobile_i2c_remove(struct platform_device *dev) 910 { 911 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); 912 913 i2c_del_adapter(&pd->adap); 914 sh_mobile_i2c_release_dma(pd); 915 pm_runtime_disable(&dev->dev); 916 return 0; 917 } 918 919 static struct platform_driver sh_mobile_i2c_driver = { 920 .driver = { 921 .name = "i2c-sh_mobile", 922 .of_match_table = sh_mobile_i2c_dt_ids, 923 }, 924 .probe = sh_mobile_i2c_probe, 925 .remove = sh_mobile_i2c_remove, 926 }; 927 928 static int __init sh_mobile_i2c_adap_init(void) 929 { 930 return platform_driver_register(&sh_mobile_i2c_driver); 931 } 932 subsys_initcall(sh_mobile_i2c_adap_init); 933 934 static void __exit sh_mobile_i2c_adap_exit(void) 935 { 936 platform_driver_unregister(&sh_mobile_i2c_driver); 937 } 938 module_exit(sh_mobile_i2c_adap_exit); 939 940 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver"); 941 MODULE_AUTHOR("Magnus Damm and Wolfram Sang"); 942 MODULE_LICENSE("GPL v2"); 943 MODULE_ALIAS("platform:i2c-sh_mobile"); 944