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 bool atomic_xfer; 133 134 struct resource *res; 135 struct dma_chan *dma_tx; 136 struct dma_chan *dma_rx; 137 struct scatterlist sg; 138 enum dma_data_direction dma_direction; 139 u8 *dma_buf; 140 }; 141 142 struct sh_mobile_dt_config { 143 int clks_per_count; 144 int (*setup)(struct sh_mobile_i2c_data *pd); 145 }; 146 147 #define IIC_FLAG_HAS_ICIC67 (1 << 0) 148 149 /* Register offsets */ 150 #define ICDR 0x00 151 #define ICCR 0x04 152 #define ICSR 0x08 153 #define ICIC 0x0c 154 #define ICCL 0x10 155 #define ICCH 0x14 156 #define ICSTART 0x70 157 158 /* Register bits */ 159 #define ICCR_ICE 0x80 160 #define ICCR_RACK 0x40 161 #define ICCR_TRS 0x10 162 #define ICCR_BBSY 0x04 163 #define ICCR_SCP 0x01 164 165 #define ICSR_SCLM 0x80 166 #define ICSR_SDAM 0x40 167 #define SW_DONE 0x20 168 #define ICSR_BUSY 0x10 169 #define ICSR_AL 0x08 170 #define ICSR_TACK 0x04 171 #define ICSR_WAIT 0x02 172 #define ICSR_DTE 0x01 173 174 #define ICIC_ICCLB8 0x80 175 #define ICIC_ICCHB8 0x40 176 #define ICIC_TDMAE 0x20 177 #define ICIC_RDMAE 0x10 178 #define ICIC_ALE 0x08 179 #define ICIC_TACKE 0x04 180 #define ICIC_WAITE 0x02 181 #define ICIC_DTEE 0x01 182 183 #define ICSTART_ICSTART 0x10 184 185 static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data) 186 { 187 if (offs == ICIC) 188 data |= pd->icic; 189 190 iowrite8(data, pd->reg + offs); 191 } 192 193 static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs) 194 { 195 return ioread8(pd->reg + offs); 196 } 197 198 static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs, 199 unsigned char set, unsigned char clr) 200 { 201 iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr); 202 } 203 204 static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf) 205 { 206 /* 207 * Conditional expression: 208 * ICCL >= COUNT_CLK * (tLOW + tf) 209 * 210 * SH-Mobile IIC hardware starts counting the LOW period of 211 * the SCL signal (tLOW) as soon as it pulls the SCL line. 212 * In order to meet the tLOW timing spec, we need to take into 213 * account the fall time of SCL signal (tf). Default tf value 214 * should be 0.3 us, for safety. 215 */ 216 return (((count_khz * (tLOW + tf)) + 5000) / 10000); 217 } 218 219 static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf) 220 { 221 /* 222 * Conditional expression: 223 * ICCH >= COUNT_CLK * (tHIGH + tf) 224 * 225 * SH-Mobile IIC hardware is aware of SCL transition period 'tr', 226 * and can ignore it. SH-Mobile IIC controller starts counting 227 * the HIGH period of the SCL signal (tHIGH) after the SCL input 228 * voltage increases at VIH. 229 * 230 * Afterward it turned out calculating ICCH using only tHIGH spec 231 * will result in violation of the tHD;STA timing spec. We need 232 * to take into account the fall time of SDA signal (tf) at START 233 * condition, in order to meet both tHIGH and tHD;STA specs. 234 */ 235 return (((count_khz * (tHIGH + tf)) + 5000) / 10000); 236 } 237 238 static int sh_mobile_i2c_check_timing(struct sh_mobile_i2c_data *pd) 239 { 240 u16 max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff; 241 242 if (pd->iccl > max_val || pd->icch > max_val) { 243 dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n", 244 pd->iccl, pd->icch); 245 return -EINVAL; 246 } 247 248 /* one more bit of ICCL in ICIC */ 249 if (pd->iccl & 0x100) 250 pd->icic |= ICIC_ICCLB8; 251 else 252 pd->icic &= ~ICIC_ICCLB8; 253 254 /* one more bit of ICCH in ICIC */ 255 if (pd->icch & 0x100) 256 pd->icic |= ICIC_ICCHB8; 257 else 258 pd->icic &= ~ICIC_ICCHB8; 259 260 dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch); 261 return 0; 262 } 263 264 static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd) 265 { 266 unsigned long i2c_clk_khz; 267 u32 tHIGH, tLOW, tf; 268 269 i2c_clk_khz = clk_get_rate(pd->clk) / 1000 / pd->clks_per_count; 270 271 if (pd->bus_speed == I2C_MAX_STANDARD_MODE_FREQ) { 272 tLOW = 47; /* tLOW = 4.7 us */ 273 tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */ 274 tf = 3; /* tf = 0.3 us */ 275 } else if (pd->bus_speed == I2C_MAX_FAST_MODE_FREQ) { 276 tLOW = 13; /* tLOW = 1.3 us */ 277 tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */ 278 tf = 3; /* tf = 0.3 us */ 279 } else { 280 dev_err(pd->dev, "unrecognized bus speed %lu Hz\n", 281 pd->bus_speed); 282 return -EINVAL; 283 } 284 285 pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf); 286 pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf); 287 288 return sh_mobile_i2c_check_timing(pd); 289 } 290 291 static int sh_mobile_i2c_v2_init(struct sh_mobile_i2c_data *pd) 292 { 293 unsigned long clks_per_cycle; 294 295 /* L = 5, H = 4, L + H = 9 */ 296 clks_per_cycle = clk_get_rate(pd->clk) / pd->bus_speed; 297 pd->iccl = DIV_ROUND_UP(clks_per_cycle * 5 / 9 - 1, pd->clks_per_count); 298 pd->icch = DIV_ROUND_UP(clks_per_cycle * 4 / 9 - 5, pd->clks_per_count); 299 300 return sh_mobile_i2c_check_timing(pd); 301 } 302 303 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, enum sh_mobile_i2c_op op) 304 { 305 unsigned char ret = 0; 306 unsigned long flags; 307 308 dev_dbg(pd->dev, "op %d\n", op); 309 310 spin_lock_irqsave(&pd->lock, flags); 311 312 switch (op) { 313 case OP_START: /* issue start and trigger DTE interrupt */ 314 iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY); 315 break; 316 case OP_TX_FIRST: /* disable DTE interrupt and write client address */ 317 iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 318 iic_wr(pd, ICDR, i2c_8bit_addr_from_msg(pd->msg)); 319 break; 320 case OP_TX: /* write data */ 321 iic_wr(pd, ICDR, pd->msg->buf[pd->pos]); 322 break; 323 case OP_TX_STOP: /* issue a stop (or rep_start) */ 324 iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS 325 : ICCR_ICE | ICCR_TRS | ICCR_BBSY); 326 break; 327 case OP_TX_TO_RX: /* select read mode */ 328 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP); 329 break; 330 case OP_RX: /* just read data */ 331 ret = iic_rd(pd, ICDR); 332 break; 333 case OP_RX_STOP: /* enable DTE interrupt, issue stop */ 334 if (!pd->atomic_xfer) 335 iic_wr(pd, ICIC, 336 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 337 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK); 338 break; 339 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */ 340 if (!pd->atomic_xfer) 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 int real_pos; 373 374 /* switch from TX (address) to RX (data) adds two interrupts */ 375 real_pos = pd->pos - 2; 376 377 if (pd->pos == -1) { 378 i2c_op(pd, OP_TX_FIRST); 379 } else if (pd->pos == 0) { 380 i2c_op(pd, OP_TX_TO_RX); 381 } else if (pd->pos == pd->msg->len) { 382 if (pd->stop_after_dma) { 383 /* Simulate PIO end condition after DMA transfer */ 384 i2c_op(pd, OP_RX_STOP); 385 pd->pos++; 386 goto done; 387 } 388 389 if (real_pos < 0) 390 i2c_op(pd, OP_RX_STOP); 391 else 392 pd->msg->buf[real_pos] = i2c_op(pd, OP_RX_STOP_DATA); 393 } else if (real_pos >= 0) { 394 pd->msg->buf[real_pos] = i2c_op(pd, OP_RX); 395 } 396 397 done: 398 pd->pos++; 399 return pd->pos == (pd->msg->len + 2); 400 } 401 402 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) 403 { 404 struct sh_mobile_i2c_data *pd = dev_id; 405 unsigned char sr; 406 int wakeup = 0; 407 408 sr = iic_rd(pd, ICSR); 409 pd->sr |= sr; /* remember state */ 410 411 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr, 412 (pd->msg->flags & I2C_M_RD) ? "read" : "write", 413 pd->pos, pd->msg->len); 414 415 /* Kick off TxDMA after preface was done */ 416 if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0) 417 iic_set_clr(pd, ICIC, ICIC_TDMAE, 0); 418 else if (sr & (ICSR_AL | ICSR_TACK)) 419 /* don't interrupt transaction - continue to issue stop */ 420 iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK)); 421 else if (pd->msg->flags & I2C_M_RD) 422 wakeup = sh_mobile_i2c_isr_rx(pd); 423 else 424 wakeup = sh_mobile_i2c_isr_tx(pd); 425 426 /* Kick off RxDMA after preface was done */ 427 if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1) 428 iic_set_clr(pd, ICIC, ICIC_RDMAE, 0); 429 430 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */ 431 iic_wr(pd, ICSR, sr & ~ICSR_WAIT); 432 433 if (wakeup) { 434 pd->sr |= SW_DONE; 435 if (!pd->atomic_xfer) 436 wake_up(&pd->wait); 437 } 438 439 /* defeat write posting to avoid spurious WAIT interrupts */ 440 iic_rd(pd, ICSR); 441 442 return IRQ_HANDLED; 443 } 444 445 static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd) 446 { 447 struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE 448 ? pd->dma_rx : pd->dma_tx; 449 450 dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg), 451 pd->msg->len, pd->dma_direction); 452 453 pd->dma_direction = DMA_NONE; 454 } 455 456 static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd) 457 { 458 if (pd->dma_direction == DMA_NONE) 459 return; 460 else if (pd->dma_direction == DMA_FROM_DEVICE) 461 dmaengine_terminate_all(pd->dma_rx); 462 else if (pd->dma_direction == DMA_TO_DEVICE) 463 dmaengine_terminate_all(pd->dma_tx); 464 465 sh_mobile_i2c_dma_unmap(pd); 466 } 467 468 static void sh_mobile_i2c_dma_callback(void *data) 469 { 470 struct sh_mobile_i2c_data *pd = data; 471 472 sh_mobile_i2c_dma_unmap(pd); 473 pd->pos = pd->msg->len; 474 pd->stop_after_dma = true; 475 476 iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE); 477 } 478 479 static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev, 480 enum dma_transfer_direction dir, dma_addr_t port_addr) 481 { 482 struct dma_chan *chan; 483 struct dma_slave_config cfg; 484 char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx"; 485 int ret; 486 487 chan = dma_request_chan(dev, chan_name); 488 if (IS_ERR(chan)) { 489 dev_dbg(dev, "request_channel failed for %s (%ld)\n", chan_name, 490 PTR_ERR(chan)); 491 return chan; 492 } 493 494 memset(&cfg, 0, sizeof(cfg)); 495 cfg.direction = dir; 496 if (dir == DMA_MEM_TO_DEV) { 497 cfg.dst_addr = port_addr; 498 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 499 } else { 500 cfg.src_addr = port_addr; 501 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 502 } 503 504 ret = dmaengine_slave_config(chan, &cfg); 505 if (ret) { 506 dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret); 507 dma_release_channel(chan); 508 return ERR_PTR(ret); 509 } 510 511 dev_dbg(dev, "got DMA channel for %s\n", chan_name); 512 return chan; 513 } 514 515 static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd) 516 { 517 bool read = pd->msg->flags & I2C_M_RD; 518 enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE; 519 struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx; 520 struct dma_async_tx_descriptor *txdesc; 521 dma_addr_t dma_addr; 522 dma_cookie_t cookie; 523 524 if (PTR_ERR(chan) == -EPROBE_DEFER) { 525 if (read) 526 chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM, 527 pd->res->start + ICDR); 528 else 529 chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV, 530 pd->res->start + ICDR); 531 } 532 533 if (IS_ERR(chan)) 534 return; 535 536 dma_addr = dma_map_single(chan->device->dev, pd->dma_buf, pd->msg->len, dir); 537 if (dma_mapping_error(chan->device->dev, dma_addr)) { 538 dev_dbg(pd->dev, "dma map failed, using PIO\n"); 539 return; 540 } 541 542 sg_dma_len(&pd->sg) = pd->msg->len; 543 sg_dma_address(&pd->sg) = dma_addr; 544 545 pd->dma_direction = dir; 546 547 txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1, 548 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV, 549 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 550 if (!txdesc) { 551 dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n"); 552 sh_mobile_i2c_cleanup_dma(pd); 553 return; 554 } 555 556 txdesc->callback = sh_mobile_i2c_dma_callback; 557 txdesc->callback_param = pd; 558 559 cookie = dmaengine_submit(txdesc); 560 if (dma_submit_error(cookie)) { 561 dev_dbg(pd->dev, "submitting dma failed, using PIO\n"); 562 sh_mobile_i2c_cleanup_dma(pd); 563 return; 564 } 565 566 dma_async_issue_pending(chan); 567 } 568 569 static void start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg, 570 bool do_init) 571 { 572 if (do_init) { 573 /* Initialize channel registers */ 574 iic_wr(pd, ICCR, ICCR_SCP); 575 576 /* Enable channel and configure rx ack */ 577 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP); 578 579 /* Set the clock */ 580 iic_wr(pd, ICCL, pd->iccl & 0xff); 581 iic_wr(pd, ICCH, pd->icch & 0xff); 582 } 583 584 pd->msg = usr_msg; 585 pd->pos = -1; 586 pd->sr = 0; 587 588 if (pd->atomic_xfer) 589 return; 590 591 pd->dma_buf = i2c_get_dma_safe_msg_buf(pd->msg, 8); 592 if (pd->dma_buf) 593 sh_mobile_i2c_xfer_dma(pd); 594 595 /* Enable all interrupts to begin with */ 596 iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 597 } 598 599 static int poll_dte(struct sh_mobile_i2c_data *pd) 600 { 601 int i; 602 603 for (i = 1000; i; i--) { 604 u_int8_t val = iic_rd(pd, ICSR); 605 606 if (val & ICSR_DTE) 607 break; 608 609 if (val & ICSR_TACK) 610 return -ENXIO; 611 612 udelay(10); 613 } 614 615 return i ? 0 : -ETIMEDOUT; 616 } 617 618 static int poll_busy(struct sh_mobile_i2c_data *pd) 619 { 620 int i; 621 622 for (i = 1000; i; i--) { 623 u_int8_t val = iic_rd(pd, ICSR); 624 625 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr); 626 627 /* the interrupt handler may wake us up before the 628 * transfer is finished, so poll the hardware 629 * until we're done. 630 */ 631 if (!(val & ICSR_BUSY)) { 632 /* handle missing acknowledge and arbitration lost */ 633 val |= pd->sr; 634 if (val & ICSR_TACK) 635 return -ENXIO; 636 if (val & ICSR_AL) 637 return -EAGAIN; 638 break; 639 } 640 641 udelay(10); 642 } 643 644 return i ? 0 : -ETIMEDOUT; 645 } 646 647 static int sh_mobile_xfer(struct sh_mobile_i2c_data *pd, 648 struct i2c_msg *msgs, int num) 649 { 650 struct i2c_msg *msg; 651 int err = 0; 652 int i; 653 long time_left; 654 655 /* Wake up device and enable clock */ 656 pm_runtime_get_sync(pd->dev); 657 658 /* Process all messages */ 659 for (i = 0; i < num; i++) { 660 bool do_start = pd->send_stop || !i; 661 msg = &msgs[i]; 662 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP; 663 pd->stop_after_dma = false; 664 665 start_ch(pd, msg, do_start); 666 667 if (do_start) 668 i2c_op(pd, OP_START); 669 670 if (pd->atomic_xfer) { 671 unsigned long j = jiffies + pd->adap.timeout; 672 673 time_left = time_before_eq(jiffies, j); 674 while (time_left && 675 !(pd->sr & (ICSR_TACK | SW_DONE))) { 676 unsigned char sr = iic_rd(pd, ICSR); 677 678 if (sr & (ICSR_AL | ICSR_TACK | 679 ICSR_WAIT | ICSR_DTE)) { 680 sh_mobile_i2c_isr(0, pd); 681 udelay(150); 682 } else { 683 cpu_relax(); 684 } 685 time_left = time_before_eq(jiffies, j); 686 } 687 } else { 688 /* The interrupt handler takes care of the rest... */ 689 time_left = wait_event_timeout(pd->wait, 690 pd->sr & (ICSR_TACK | SW_DONE), 691 pd->adap.timeout); 692 693 /* 'stop_after_dma' tells if DMA xfer was complete */ 694 i2c_put_dma_safe_msg_buf(pd->dma_buf, pd->msg, 695 pd->stop_after_dma); 696 } 697 698 if (!time_left) { 699 dev_err(pd->dev, "Transfer request timed out\n"); 700 if (pd->dma_direction != DMA_NONE) 701 sh_mobile_i2c_cleanup_dma(pd); 702 703 err = -ETIMEDOUT; 704 break; 705 } 706 707 if (pd->send_stop) 708 err = poll_busy(pd); 709 else 710 err = poll_dte(pd); 711 if (err < 0) 712 break; 713 } 714 715 /* Disable channel */ 716 iic_wr(pd, ICCR, ICCR_SCP); 717 718 /* Disable clock and mark device as idle */ 719 pm_runtime_put_sync(pd->dev); 720 721 return err ?: num; 722 } 723 724 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, 725 struct i2c_msg *msgs, 726 int num) 727 { 728 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter); 729 730 pd->atomic_xfer = false; 731 return sh_mobile_xfer(pd, msgs, num); 732 } 733 734 static int sh_mobile_i2c_xfer_atomic(struct i2c_adapter *adapter, 735 struct i2c_msg *msgs, 736 int num) 737 { 738 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter); 739 740 pd->atomic_xfer = true; 741 return sh_mobile_xfer(pd, msgs, num); 742 } 743 744 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter) 745 { 746 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; 747 } 748 749 static const struct i2c_algorithm sh_mobile_i2c_algorithm = { 750 .functionality = sh_mobile_i2c_func, 751 .master_xfer = sh_mobile_i2c_xfer, 752 .master_xfer_atomic = sh_mobile_i2c_xfer_atomic, 753 }; 754 755 static const struct i2c_adapter_quirks sh_mobile_i2c_quirks = { 756 .flags = I2C_AQ_NO_ZERO_LEN_READ, 757 }; 758 759 /* 760 * r8a7740 has an errata regarding I2C I/O pad reset needing this workaround. 761 */ 762 static int sh_mobile_i2c_r8a7740_workaround(struct sh_mobile_i2c_data *pd) 763 { 764 iic_set_clr(pd, ICCR, ICCR_ICE, 0); 765 iic_rd(pd, ICCR); /* dummy read */ 766 767 iic_set_clr(pd, ICSTART, ICSTART_ICSTART, 0); 768 iic_rd(pd, ICSTART); /* dummy read */ 769 770 udelay(10); 771 772 iic_wr(pd, ICCR, ICCR_SCP); 773 iic_wr(pd, ICSTART, 0); 774 775 udelay(10); 776 777 iic_wr(pd, ICCR, ICCR_TRS); 778 udelay(10); 779 iic_wr(pd, ICCR, 0); 780 udelay(10); 781 iic_wr(pd, ICCR, ICCR_TRS); 782 udelay(10); 783 784 return sh_mobile_i2c_init(pd); 785 } 786 787 static const struct sh_mobile_dt_config default_dt_config = { 788 .clks_per_count = 1, 789 .setup = sh_mobile_i2c_init, 790 }; 791 792 static const struct sh_mobile_dt_config fast_clock_dt_config = { 793 .clks_per_count = 2, 794 .setup = sh_mobile_i2c_init, 795 }; 796 797 static const struct sh_mobile_dt_config v2_freq_calc_dt_config = { 798 .clks_per_count = 2, 799 .setup = sh_mobile_i2c_v2_init, 800 }; 801 802 static const struct sh_mobile_dt_config r8a7740_dt_config = { 803 .clks_per_count = 1, 804 .setup = sh_mobile_i2c_r8a7740_workaround, 805 }; 806 807 static const struct of_device_id sh_mobile_i2c_dt_ids[] = { 808 { .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config }, 809 { .compatible = "renesas,iic-r8a7740", .data = &r8a7740_dt_config }, 810 { .compatible = "renesas,iic-r8a774c0", .data = &fast_clock_dt_config }, 811 { .compatible = "renesas,iic-r8a7790", .data = &v2_freq_calc_dt_config }, 812 { .compatible = "renesas,iic-r8a7791", .data = &v2_freq_calc_dt_config }, 813 { .compatible = "renesas,iic-r8a7792", .data = &v2_freq_calc_dt_config }, 814 { .compatible = "renesas,iic-r8a7793", .data = &v2_freq_calc_dt_config }, 815 { .compatible = "renesas,iic-r8a7794", .data = &v2_freq_calc_dt_config }, 816 { .compatible = "renesas,iic-r8a7795", .data = &v2_freq_calc_dt_config }, 817 { .compatible = "renesas,iic-r8a77990", .data = &v2_freq_calc_dt_config }, 818 { .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config }, 819 { .compatible = "renesas,rcar-gen2-iic", .data = &v2_freq_calc_dt_config }, 820 { .compatible = "renesas,rcar-gen3-iic", .data = &v2_freq_calc_dt_config }, 821 { .compatible = "renesas,rmobile-iic", .data = &default_dt_config }, 822 {}, 823 }; 824 MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids); 825 826 static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd) 827 { 828 if (!IS_ERR(pd->dma_tx)) { 829 dma_release_channel(pd->dma_tx); 830 pd->dma_tx = ERR_PTR(-EPROBE_DEFER); 831 } 832 833 if (!IS_ERR(pd->dma_rx)) { 834 dma_release_channel(pd->dma_rx); 835 pd->dma_rx = ERR_PTR(-EPROBE_DEFER); 836 } 837 } 838 839 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd) 840 { 841 struct resource *res; 842 resource_size_t n; 843 int k = 0, ret; 844 845 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) { 846 for (n = res->start; n <= res->end; n++) { 847 ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr, 848 0, dev_name(&dev->dev), pd); 849 if (ret) { 850 dev_err(&dev->dev, "cannot request IRQ %pa\n", &n); 851 return ret; 852 } 853 } 854 k++; 855 } 856 857 return k > 0 ? 0 : -ENOENT; 858 } 859 860 static int sh_mobile_i2c_probe(struct platform_device *dev) 861 { 862 struct sh_mobile_i2c_data *pd; 863 struct i2c_adapter *adap; 864 struct resource *res; 865 const struct sh_mobile_dt_config *config; 866 int ret; 867 u32 bus_speed; 868 869 pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL); 870 if (!pd) 871 return -ENOMEM; 872 873 pd->clk = devm_clk_get(&dev->dev, NULL); 874 if (IS_ERR(pd->clk)) { 875 dev_err(&dev->dev, "cannot get clock\n"); 876 return PTR_ERR(pd->clk); 877 } 878 879 ret = sh_mobile_i2c_hook_irqs(dev, pd); 880 if (ret) 881 return ret; 882 883 pd->dev = &dev->dev; 884 platform_set_drvdata(dev, pd); 885 886 res = platform_get_resource(dev, IORESOURCE_MEM, 0); 887 888 pd->res = res; 889 pd->reg = devm_ioremap_resource(&dev->dev, res); 890 if (IS_ERR(pd->reg)) 891 return PTR_ERR(pd->reg); 892 893 ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed); 894 pd->bus_speed = (ret || !bus_speed) ? I2C_MAX_STANDARD_MODE_FREQ : bus_speed; 895 pd->clks_per_count = 1; 896 897 /* Newer variants come with two new bits in ICIC */ 898 if (resource_size(res) > 0x17) 899 pd->flags |= IIC_FLAG_HAS_ICIC67; 900 901 pm_runtime_enable(&dev->dev); 902 pm_runtime_get_sync(&dev->dev); 903 904 config = of_device_get_match_data(&dev->dev); 905 if (config) { 906 pd->clks_per_count = config->clks_per_count; 907 ret = config->setup(pd); 908 } else { 909 ret = sh_mobile_i2c_init(pd); 910 } 911 912 pm_runtime_put_sync(&dev->dev); 913 if (ret) 914 return ret; 915 916 /* Init DMA */ 917 sg_init_table(&pd->sg, 1); 918 pd->dma_direction = DMA_NONE; 919 pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER); 920 921 /* setup the private data */ 922 adap = &pd->adap; 923 i2c_set_adapdata(adap, pd); 924 925 adap->owner = THIS_MODULE; 926 adap->algo = &sh_mobile_i2c_algorithm; 927 adap->quirks = &sh_mobile_i2c_quirks; 928 adap->dev.parent = &dev->dev; 929 adap->retries = 5; 930 adap->nr = dev->id; 931 adap->dev.of_node = dev->dev.of_node; 932 933 strlcpy(adap->name, dev->name, sizeof(adap->name)); 934 935 spin_lock_init(&pd->lock); 936 init_waitqueue_head(&pd->wait); 937 938 ret = i2c_add_numbered_adapter(adap); 939 if (ret < 0) { 940 sh_mobile_i2c_release_dma(pd); 941 return ret; 942 } 943 944 dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed); 945 946 return 0; 947 } 948 949 static int sh_mobile_i2c_remove(struct platform_device *dev) 950 { 951 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); 952 953 i2c_del_adapter(&pd->adap); 954 sh_mobile_i2c_release_dma(pd); 955 pm_runtime_disable(&dev->dev); 956 return 0; 957 } 958 959 #ifdef CONFIG_PM_SLEEP 960 static int sh_mobile_i2c_suspend(struct device *dev) 961 { 962 struct sh_mobile_i2c_data *pd = dev_get_drvdata(dev); 963 964 i2c_mark_adapter_suspended(&pd->adap); 965 return 0; 966 } 967 968 static int sh_mobile_i2c_resume(struct device *dev) 969 { 970 struct sh_mobile_i2c_data *pd = dev_get_drvdata(dev); 971 972 i2c_mark_adapter_resumed(&pd->adap); 973 return 0; 974 } 975 976 static const struct dev_pm_ops sh_mobile_i2c_pm_ops = { 977 SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(sh_mobile_i2c_suspend, 978 sh_mobile_i2c_resume) 979 }; 980 981 #define DEV_PM_OPS (&sh_mobile_i2c_pm_ops) 982 #else 983 #define DEV_PM_OPS NULL 984 #endif /* CONFIG_PM_SLEEP */ 985 986 static struct platform_driver sh_mobile_i2c_driver = { 987 .driver = { 988 .name = "i2c-sh_mobile", 989 .of_match_table = sh_mobile_i2c_dt_ids, 990 .pm = DEV_PM_OPS, 991 }, 992 .probe = sh_mobile_i2c_probe, 993 .remove = sh_mobile_i2c_remove, 994 }; 995 996 static int __init sh_mobile_i2c_adap_init(void) 997 { 998 return platform_driver_register(&sh_mobile_i2c_driver); 999 } 1000 subsys_initcall(sh_mobile_i2c_adap_init); 1001 1002 static void __exit sh_mobile_i2c_adap_exit(void) 1003 { 1004 platform_driver_unregister(&sh_mobile_i2c_driver); 1005 } 1006 module_exit(sh_mobile_i2c_adap_exit); 1007 1008 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver"); 1009 MODULE_AUTHOR("Magnus Damm"); 1010 MODULE_AUTHOR("Wolfram Sang"); 1011 MODULE_LICENSE("GPL v2"); 1012 MODULE_ALIAS("platform:i2c-sh_mobile"); 1013