1 /* 2 * SuperH Mobile I2C Controller 3 * 4 * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com> 5 * 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 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License as published by 13 * the Free Software Foundation; either version 2 of the License 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 */ 20 21 #include <linux/clk.h> 22 #include <linux/delay.h> 23 #include <linux/dmaengine.h> 24 #include <linux/dma-mapping.h> 25 #include <linux/err.h> 26 #include <linux/i2c.h> 27 #include <linux/i2c/i2c-sh_mobile.h> 28 #include <linux/init.h> 29 #include <linux/interrupt.h> 30 #include <linux/io.h> 31 #include <linux/kernel.h> 32 #include <linux/module.h> 33 #include <linux/of_device.h> 34 #include <linux/platform_device.h> 35 #include <linux/pm_runtime.h> 36 #include <linux/slab.h> 37 38 /* Transmit operation: */ 39 /* */ 40 /* 0 byte transmit */ 41 /* BUS: S A8 ACK P(*) */ 42 /* IRQ: DTE WAIT */ 43 /* ICIC: */ 44 /* ICCR: 0x94 0x90 */ 45 /* ICDR: A8 */ 46 /* */ 47 /* 1 byte transmit */ 48 /* BUS: S A8 ACK D8(1) ACK P(*) */ 49 /* IRQ: DTE WAIT WAIT */ 50 /* ICIC: -DTE */ 51 /* ICCR: 0x94 0x90 */ 52 /* ICDR: A8 D8(1) */ 53 /* */ 54 /* 2 byte transmit */ 55 /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P(*) */ 56 /* IRQ: DTE WAIT WAIT WAIT */ 57 /* ICIC: -DTE */ 58 /* ICCR: 0x94 0x90 */ 59 /* ICDR: A8 D8(1) D8(2) */ 60 /* */ 61 /* 3 bytes or more, +---------+ gets repeated */ 62 /* */ 63 /* */ 64 /* Receive operation: */ 65 /* */ 66 /* 0 byte receive - not supported since slave may hold SDA low */ 67 /* */ 68 /* 1 byte receive [TX] | [RX] */ 69 /* BUS: S A8 ACK | D8(1) ACK P(*) */ 70 /* IRQ: DTE WAIT | WAIT DTE */ 71 /* ICIC: -DTE | +DTE */ 72 /* ICCR: 0x94 0x81 | 0xc0 */ 73 /* ICDR: A8 | D8(1) */ 74 /* */ 75 /* 2 byte receive [TX]| [RX] */ 76 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P(*) */ 77 /* IRQ: DTE WAIT | WAIT WAIT DTE */ 78 /* ICIC: -DTE | +DTE */ 79 /* ICCR: 0x94 0x81 | 0xc0 */ 80 /* ICDR: A8 | D8(1) D8(2) */ 81 /* */ 82 /* 3 byte receive [TX] | [RX] (*) */ 83 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */ 84 /* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */ 85 /* ICIC: -DTE | +DTE */ 86 /* ICCR: 0x94 0x81 | 0xc0 */ 87 /* ICDR: A8 | D8(1) D8(2) D8(3) */ 88 /* */ 89 /* 4 bytes or more, this part is repeated +---------+ */ 90 /* */ 91 /* */ 92 /* Interrupt order and BUSY flag */ 93 /* ___ _ */ 94 /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */ 95 /* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */ 96 /* */ 97 /* S D7 D6 D5 D4 D3 D2 D1 D0 P(*) */ 98 /* ___ */ 99 /* WAIT IRQ ________________________________/ \___________ */ 100 /* TACK IRQ ____________________________________/ \_______ */ 101 /* DTE IRQ __________________________________________/ \_ */ 102 /* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */ 103 /* _______________________________________________ */ 104 /* BUSY __/ \_ */ 105 /* */ 106 /* (*) The STOP condition is only sent by the master at the end of the last */ 107 /* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */ 108 /* only cleared after the STOP condition, so, between messages we have to */ 109 /* poll for the DTE bit. */ 110 /* */ 111 112 enum sh_mobile_i2c_op { 113 OP_START = 0, 114 OP_TX_FIRST, 115 OP_TX, 116 OP_TX_STOP, 117 OP_TX_STOP_DATA, 118 OP_TX_TO_RX, 119 OP_RX, 120 OP_RX_STOP, 121 OP_RX_STOP_DATA, 122 }; 123 124 struct sh_mobile_i2c_data { 125 struct device *dev; 126 void __iomem *reg; 127 struct i2c_adapter adap; 128 unsigned long bus_speed; 129 unsigned int clks_per_count; 130 struct clk *clk; 131 u_int8_t icic; 132 u_int8_t flags; 133 u_int16_t iccl; 134 u_int16_t icch; 135 136 spinlock_t lock; 137 wait_queue_head_t wait; 138 struct i2c_msg *msg; 139 int pos; 140 int sr; 141 bool send_stop; 142 bool stop_after_dma; 143 144 struct resource *res; 145 struct dma_chan *dma_tx; 146 struct dma_chan *dma_rx; 147 struct scatterlist sg; 148 enum dma_data_direction dma_direction; 149 }; 150 151 struct sh_mobile_dt_config { 152 int clks_per_count; 153 void (*setup)(struct sh_mobile_i2c_data *pd); 154 }; 155 156 #define IIC_FLAG_HAS_ICIC67 (1 << 0) 157 158 #define STANDARD_MODE 100000 159 #define FAST_MODE 400000 160 161 /* Register offsets */ 162 #define ICDR 0x00 163 #define ICCR 0x04 164 #define ICSR 0x08 165 #define ICIC 0x0c 166 #define ICCL 0x10 167 #define ICCH 0x14 168 #define ICSTART 0x70 169 170 /* Register bits */ 171 #define ICCR_ICE 0x80 172 #define ICCR_RACK 0x40 173 #define ICCR_TRS 0x10 174 #define ICCR_BBSY 0x04 175 #define ICCR_SCP 0x01 176 177 #define ICSR_SCLM 0x80 178 #define ICSR_SDAM 0x40 179 #define SW_DONE 0x20 180 #define ICSR_BUSY 0x10 181 #define ICSR_AL 0x08 182 #define ICSR_TACK 0x04 183 #define ICSR_WAIT 0x02 184 #define ICSR_DTE 0x01 185 186 #define ICIC_ICCLB8 0x80 187 #define ICIC_ICCHB8 0x40 188 #define ICIC_TDMAE 0x20 189 #define ICIC_RDMAE 0x10 190 #define ICIC_ALE 0x08 191 #define ICIC_TACKE 0x04 192 #define ICIC_WAITE 0x02 193 #define ICIC_DTEE 0x01 194 195 #define ICSTART_ICSTART 0x10 196 197 static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data) 198 { 199 if (offs == ICIC) 200 data |= pd->icic; 201 202 iowrite8(data, pd->reg + offs); 203 } 204 205 static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs) 206 { 207 return ioread8(pd->reg + offs); 208 } 209 210 static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs, 211 unsigned char set, unsigned char clr) 212 { 213 iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr); 214 } 215 216 static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf) 217 { 218 /* 219 * Conditional expression: 220 * ICCL >= COUNT_CLK * (tLOW + tf) 221 * 222 * SH-Mobile IIC hardware starts counting the LOW period of 223 * the SCL signal (tLOW) as soon as it pulls the SCL line. 224 * In order to meet the tLOW timing spec, we need to take into 225 * account the fall time of SCL signal (tf). Default tf value 226 * should be 0.3 us, for safety. 227 */ 228 return (((count_khz * (tLOW + tf)) + 5000) / 10000); 229 } 230 231 static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf) 232 { 233 /* 234 * Conditional expression: 235 * ICCH >= COUNT_CLK * (tHIGH + tf) 236 * 237 * SH-Mobile IIC hardware is aware of SCL transition period 'tr', 238 * and can ignore it. SH-Mobile IIC controller starts counting 239 * the HIGH period of the SCL signal (tHIGH) after the SCL input 240 * voltage increases at VIH. 241 * 242 * Afterward it turned out calculating ICCH using only tHIGH spec 243 * will result in violation of the tHD;STA timing spec. We need 244 * to take into account the fall time of SDA signal (tf) at START 245 * condition, in order to meet both tHIGH and tHD;STA specs. 246 */ 247 return (((count_khz * (tHIGH + tf)) + 5000) / 10000); 248 } 249 250 static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd) 251 { 252 unsigned long i2c_clk_khz; 253 u32 tHIGH, tLOW, tf; 254 uint16_t max_val; 255 256 /* Get clock rate after clock is enabled */ 257 clk_prepare_enable(pd->clk); 258 i2c_clk_khz = clk_get_rate(pd->clk) / 1000; 259 clk_disable_unprepare(pd->clk); 260 i2c_clk_khz /= pd->clks_per_count; 261 262 if (pd->bus_speed == STANDARD_MODE) { 263 tLOW = 47; /* tLOW = 4.7 us */ 264 tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */ 265 tf = 3; /* tf = 0.3 us */ 266 } else if (pd->bus_speed == FAST_MODE) { 267 tLOW = 13; /* tLOW = 1.3 us */ 268 tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */ 269 tf = 3; /* tf = 0.3 us */ 270 } else { 271 dev_err(pd->dev, "unrecognized bus speed %lu Hz\n", 272 pd->bus_speed); 273 return -EINVAL; 274 } 275 276 pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf); 277 pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf); 278 279 max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff; 280 if (pd->iccl > max_val || pd->icch > max_val) { 281 dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n", 282 pd->iccl, pd->icch); 283 return -EINVAL; 284 } 285 286 /* one more bit of ICCL in ICIC */ 287 if (pd->iccl & 0x100) 288 pd->icic |= ICIC_ICCLB8; 289 else 290 pd->icic &= ~ICIC_ICCLB8; 291 292 /* one more bit of ICCH in ICIC */ 293 if (pd->icch & 0x100) 294 pd->icic |= ICIC_ICCHB8; 295 else 296 pd->icic &= ~ICIC_ICCHB8; 297 298 dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch); 299 return 0; 300 } 301 302 static void activate_ch(struct sh_mobile_i2c_data *pd) 303 { 304 /* Wake up device and enable clock */ 305 pm_runtime_get_sync(pd->dev); 306 clk_prepare_enable(pd->clk); 307 308 /* Enable channel and configure rx ack */ 309 iic_set_clr(pd, ICCR, ICCR_ICE, 0); 310 311 /* Mask all interrupts */ 312 iic_wr(pd, ICIC, 0); 313 314 /* Set the clock */ 315 iic_wr(pd, ICCL, pd->iccl & 0xff); 316 iic_wr(pd, ICCH, pd->icch & 0xff); 317 } 318 319 static void deactivate_ch(struct sh_mobile_i2c_data *pd) 320 { 321 /* Clear/disable interrupts */ 322 iic_wr(pd, ICSR, 0); 323 iic_wr(pd, ICIC, 0); 324 325 /* Disable channel */ 326 iic_set_clr(pd, ICCR, 0, ICCR_ICE); 327 328 /* Disable clock and mark device as idle */ 329 clk_disable_unprepare(pd->clk); 330 pm_runtime_put_sync(pd->dev); 331 } 332 333 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, 334 enum sh_mobile_i2c_op op, unsigned char data) 335 { 336 unsigned char ret = 0; 337 unsigned long flags; 338 339 dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data); 340 341 spin_lock_irqsave(&pd->lock, flags); 342 343 switch (op) { 344 case OP_START: /* issue start and trigger DTE interrupt */ 345 iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY); 346 break; 347 case OP_TX_FIRST: /* disable DTE interrupt and write data */ 348 iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 349 iic_wr(pd, ICDR, data); 350 break; 351 case OP_TX: /* write data */ 352 iic_wr(pd, ICDR, data); 353 break; 354 case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */ 355 iic_wr(pd, ICDR, data); 356 /* fallthrough */ 357 case OP_TX_STOP: /* issue a stop */ 358 iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS 359 : ICCR_ICE | ICCR_TRS | ICCR_BBSY); 360 break; 361 case OP_TX_TO_RX: /* select read mode */ 362 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP); 363 break; 364 case OP_RX: /* just read data */ 365 ret = iic_rd(pd, ICDR); 366 break; 367 case OP_RX_STOP: /* enable DTE interrupt, issue stop */ 368 iic_wr(pd, ICIC, 369 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 370 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK); 371 break; 372 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */ 373 iic_wr(pd, ICIC, 374 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 375 ret = iic_rd(pd, ICDR); 376 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK); 377 break; 378 } 379 380 spin_unlock_irqrestore(&pd->lock, flags); 381 382 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret); 383 return ret; 384 } 385 386 static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd) 387 { 388 return pd->pos == -1; 389 } 390 391 static bool sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd) 392 { 393 return pd->pos == pd->msg->len - 1; 394 } 395 396 static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd, 397 unsigned char *buf) 398 { 399 switch (pd->pos) { 400 case -1: 401 *buf = i2c_8bit_addr_from_msg(pd->msg); 402 break; 403 default: 404 *buf = pd->msg->buf[pd->pos]; 405 } 406 } 407 408 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd) 409 { 410 unsigned char data; 411 412 if (pd->pos == pd->msg->len) { 413 /* Send stop if we haven't yet (DMA case) */ 414 if (pd->send_stop && pd->stop_after_dma) 415 i2c_op(pd, OP_TX_STOP, 0); 416 return 1; 417 } 418 419 sh_mobile_i2c_get_data(pd, &data); 420 421 if (sh_mobile_i2c_is_last_byte(pd)) 422 i2c_op(pd, OP_TX_STOP_DATA, data); 423 else if (sh_mobile_i2c_is_first_byte(pd)) 424 i2c_op(pd, OP_TX_FIRST, data); 425 else 426 i2c_op(pd, OP_TX, data); 427 428 pd->pos++; 429 return 0; 430 } 431 432 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd) 433 { 434 unsigned char data; 435 int real_pos; 436 437 do { 438 if (pd->pos <= -1) { 439 sh_mobile_i2c_get_data(pd, &data); 440 441 if (sh_mobile_i2c_is_first_byte(pd)) 442 i2c_op(pd, OP_TX_FIRST, data); 443 else 444 i2c_op(pd, OP_TX, data); 445 break; 446 } 447 448 if (pd->pos == 0) { 449 i2c_op(pd, OP_TX_TO_RX, 0); 450 break; 451 } 452 453 real_pos = pd->pos - 2; 454 455 if (pd->pos == pd->msg->len) { 456 if (pd->stop_after_dma) { 457 /* Simulate PIO end condition after DMA transfer */ 458 i2c_op(pd, OP_RX_STOP, 0); 459 pd->pos++; 460 break; 461 } 462 463 if (real_pos < 0) { 464 i2c_op(pd, OP_RX_STOP, 0); 465 break; 466 } 467 data = i2c_op(pd, OP_RX_STOP_DATA, 0); 468 } else 469 data = i2c_op(pd, OP_RX, 0); 470 471 if (real_pos >= 0) 472 pd->msg->buf[real_pos] = data; 473 } while (0); 474 475 pd->pos++; 476 return pd->pos == (pd->msg->len + 2); 477 } 478 479 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) 480 { 481 struct sh_mobile_i2c_data *pd = dev_id; 482 unsigned char sr; 483 int wakeup = 0; 484 485 sr = iic_rd(pd, ICSR); 486 pd->sr |= sr; /* remember state */ 487 488 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr, 489 (pd->msg->flags & I2C_M_RD) ? "read" : "write", 490 pd->pos, pd->msg->len); 491 492 /* Kick off TxDMA after preface was done */ 493 if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0) 494 iic_set_clr(pd, ICIC, ICIC_TDMAE, 0); 495 else if (sr & (ICSR_AL | ICSR_TACK)) 496 /* don't interrupt transaction - continue to issue stop */ 497 iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK)); 498 else if (pd->msg->flags & I2C_M_RD) 499 wakeup = sh_mobile_i2c_isr_rx(pd); 500 else 501 wakeup = sh_mobile_i2c_isr_tx(pd); 502 503 /* Kick off RxDMA after preface was done */ 504 if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1) 505 iic_set_clr(pd, ICIC, ICIC_RDMAE, 0); 506 507 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */ 508 iic_wr(pd, ICSR, sr & ~ICSR_WAIT); 509 510 if (wakeup) { 511 pd->sr |= SW_DONE; 512 wake_up(&pd->wait); 513 } 514 515 /* defeat write posting to avoid spurious WAIT interrupts */ 516 iic_rd(pd, ICSR); 517 518 return IRQ_HANDLED; 519 } 520 521 static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd) 522 { 523 struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE 524 ? pd->dma_rx : pd->dma_tx; 525 526 dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg), 527 pd->msg->len, pd->dma_direction); 528 529 pd->dma_direction = DMA_NONE; 530 } 531 532 static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd) 533 { 534 if (pd->dma_direction == DMA_NONE) 535 return; 536 else if (pd->dma_direction == DMA_FROM_DEVICE) 537 dmaengine_terminate_all(pd->dma_rx); 538 else if (pd->dma_direction == DMA_TO_DEVICE) 539 dmaengine_terminate_all(pd->dma_tx); 540 541 sh_mobile_i2c_dma_unmap(pd); 542 } 543 544 static void sh_mobile_i2c_dma_callback(void *data) 545 { 546 struct sh_mobile_i2c_data *pd = data; 547 548 sh_mobile_i2c_dma_unmap(pd); 549 pd->pos = pd->msg->len; 550 pd->stop_after_dma = true; 551 552 iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE); 553 } 554 555 static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev, 556 enum dma_transfer_direction dir, dma_addr_t port_addr) 557 { 558 struct dma_chan *chan; 559 struct dma_slave_config cfg; 560 char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx"; 561 int ret; 562 563 chan = dma_request_slave_channel_reason(dev, chan_name); 564 if (IS_ERR(chan)) { 565 ret = PTR_ERR(chan); 566 dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret); 567 return chan; 568 } 569 570 memset(&cfg, 0, sizeof(cfg)); 571 cfg.direction = dir; 572 if (dir == DMA_MEM_TO_DEV) { 573 cfg.dst_addr = port_addr; 574 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 575 } else { 576 cfg.src_addr = port_addr; 577 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 578 } 579 580 ret = dmaengine_slave_config(chan, &cfg); 581 if (ret) { 582 dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret); 583 dma_release_channel(chan); 584 return ERR_PTR(ret); 585 } 586 587 dev_dbg(dev, "got DMA channel for %s\n", chan_name); 588 return chan; 589 } 590 591 static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd) 592 { 593 bool read = pd->msg->flags & I2C_M_RD; 594 enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE; 595 struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx; 596 struct dma_async_tx_descriptor *txdesc; 597 dma_addr_t dma_addr; 598 dma_cookie_t cookie; 599 600 if (PTR_ERR(chan) == -EPROBE_DEFER) { 601 if (read) 602 chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM, 603 pd->res->start + ICDR); 604 else 605 chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV, 606 pd->res->start + ICDR); 607 } 608 609 if (IS_ERR(chan)) 610 return; 611 612 dma_addr = dma_map_single(chan->device->dev, pd->msg->buf, pd->msg->len, dir); 613 if (dma_mapping_error(pd->dev, dma_addr)) { 614 dev_dbg(pd->dev, "dma map failed, using PIO\n"); 615 return; 616 } 617 618 sg_dma_len(&pd->sg) = pd->msg->len; 619 sg_dma_address(&pd->sg) = dma_addr; 620 621 pd->dma_direction = dir; 622 623 txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1, 624 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV, 625 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 626 if (!txdesc) { 627 dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n"); 628 sh_mobile_i2c_cleanup_dma(pd); 629 return; 630 } 631 632 txdesc->callback = sh_mobile_i2c_dma_callback; 633 txdesc->callback_param = pd; 634 635 cookie = dmaengine_submit(txdesc); 636 if (dma_submit_error(cookie)) { 637 dev_dbg(pd->dev, "submitting dma failed, using PIO\n"); 638 sh_mobile_i2c_cleanup_dma(pd); 639 return; 640 } 641 642 dma_async_issue_pending(chan); 643 } 644 645 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg, 646 bool do_init) 647 { 648 if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) { 649 dev_err(pd->dev, "Unsupported zero length i2c read\n"); 650 return -EOPNOTSUPP; 651 } 652 653 if (do_init) { 654 /* Initialize channel registers */ 655 iic_set_clr(pd, ICCR, 0, ICCR_ICE); 656 657 /* Enable channel and configure rx ack */ 658 iic_set_clr(pd, ICCR, ICCR_ICE, 0); 659 660 /* Set the clock */ 661 iic_wr(pd, ICCL, pd->iccl & 0xff); 662 iic_wr(pd, ICCH, pd->icch & 0xff); 663 } 664 665 pd->msg = usr_msg; 666 pd->pos = -1; 667 pd->sr = 0; 668 669 if (pd->msg->len > 8) 670 sh_mobile_i2c_xfer_dma(pd); 671 672 /* Enable all interrupts to begin with */ 673 iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); 674 return 0; 675 } 676 677 static int poll_dte(struct sh_mobile_i2c_data *pd) 678 { 679 int i; 680 681 for (i = 1000; i; i--) { 682 u_int8_t val = iic_rd(pd, ICSR); 683 684 if (val & ICSR_DTE) 685 break; 686 687 if (val & ICSR_TACK) 688 return -ENXIO; 689 690 udelay(10); 691 } 692 693 return i ? 0 : -ETIMEDOUT; 694 } 695 696 static int poll_busy(struct sh_mobile_i2c_data *pd) 697 { 698 int i; 699 700 for (i = 1000; i; i--) { 701 u_int8_t val = iic_rd(pd, ICSR); 702 703 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr); 704 705 /* the interrupt handler may wake us up before the 706 * transfer is finished, so poll the hardware 707 * until we're done. 708 */ 709 if (!(val & ICSR_BUSY)) { 710 /* handle missing acknowledge and arbitration lost */ 711 val |= pd->sr; 712 if (val & ICSR_TACK) 713 return -ENXIO; 714 if (val & ICSR_AL) 715 return -EAGAIN; 716 break; 717 } 718 719 udelay(10); 720 } 721 722 return i ? 0 : -ETIMEDOUT; 723 } 724 725 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, 726 struct i2c_msg *msgs, 727 int num) 728 { 729 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter); 730 struct i2c_msg *msg; 731 int err = 0; 732 int i; 733 long timeout; 734 735 activate_ch(pd); 736 737 /* Process all messages */ 738 for (i = 0; i < num; i++) { 739 bool do_start = pd->send_stop || !i; 740 msg = &msgs[i]; 741 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP; 742 pd->stop_after_dma = false; 743 744 err = start_ch(pd, msg, do_start); 745 if (err) 746 break; 747 748 if (do_start) 749 i2c_op(pd, OP_START, 0); 750 751 /* The interrupt handler takes care of the rest... */ 752 timeout = wait_event_timeout(pd->wait, 753 pd->sr & (ICSR_TACK | SW_DONE), 754 adapter->timeout); 755 if (!timeout) { 756 dev_err(pd->dev, "Transfer request timed out\n"); 757 if (pd->dma_direction != DMA_NONE) 758 sh_mobile_i2c_cleanup_dma(pd); 759 760 err = -ETIMEDOUT; 761 break; 762 } 763 764 if (pd->send_stop) 765 err = poll_busy(pd); 766 else 767 err = poll_dte(pd); 768 if (err < 0) 769 break; 770 } 771 772 deactivate_ch(pd); 773 774 if (!err) 775 err = num; 776 return err; 777 } 778 779 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter) 780 { 781 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; 782 } 783 784 static struct i2c_algorithm sh_mobile_i2c_algorithm = { 785 .functionality = sh_mobile_i2c_func, 786 .master_xfer = sh_mobile_i2c_xfer, 787 }; 788 789 /* 790 * r8a7740 chip has lasting errata on I2C I/O pad reset. 791 * this is work-around for it. 792 */ 793 static void sh_mobile_i2c_r8a7740_workaround(struct sh_mobile_i2c_data *pd) 794 { 795 iic_set_clr(pd, ICCR, ICCR_ICE, 0); 796 iic_rd(pd, ICCR); /* dummy read */ 797 798 iic_set_clr(pd, ICSTART, ICSTART_ICSTART, 0); 799 iic_rd(pd, ICSTART); /* dummy read */ 800 801 udelay(10); 802 803 iic_wr(pd, ICCR, ICCR_SCP); 804 iic_wr(pd, ICSTART, 0); 805 806 udelay(10); 807 808 iic_wr(pd, ICCR, ICCR_TRS); 809 udelay(10); 810 iic_wr(pd, ICCR, 0); 811 udelay(10); 812 iic_wr(pd, ICCR, ICCR_TRS); 813 udelay(10); 814 } 815 816 static const struct sh_mobile_dt_config default_dt_config = { 817 .clks_per_count = 1, 818 }; 819 820 static const struct sh_mobile_dt_config fast_clock_dt_config = { 821 .clks_per_count = 2, 822 }; 823 824 static const struct sh_mobile_dt_config r8a7740_dt_config = { 825 .clks_per_count = 1, 826 .setup = sh_mobile_i2c_r8a7740_workaround, 827 }; 828 829 static const struct of_device_id sh_mobile_i2c_dt_ids[] = { 830 { .compatible = "renesas,rmobile-iic", .data = &default_dt_config }, 831 { .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config }, 832 { .compatible = "renesas,iic-r8a7740", .data = &r8a7740_dt_config }, 833 { .compatible = "renesas,iic-r8a7790", .data = &fast_clock_dt_config }, 834 { .compatible = "renesas,iic-r8a7791", .data = &fast_clock_dt_config }, 835 { .compatible = "renesas,iic-r8a7792", .data = &fast_clock_dt_config }, 836 { .compatible = "renesas,iic-r8a7793", .data = &fast_clock_dt_config }, 837 { .compatible = "renesas,iic-r8a7794", .data = &fast_clock_dt_config }, 838 { .compatible = "renesas,iic-r8a7795", .data = &fast_clock_dt_config }, 839 { .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config }, 840 {}, 841 }; 842 MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids); 843 844 static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd) 845 { 846 if (!IS_ERR(pd->dma_tx)) { 847 dma_release_channel(pd->dma_tx); 848 pd->dma_tx = ERR_PTR(-EPROBE_DEFER); 849 } 850 851 if (!IS_ERR(pd->dma_rx)) { 852 dma_release_channel(pd->dma_rx); 853 pd->dma_rx = ERR_PTR(-EPROBE_DEFER); 854 } 855 } 856 857 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd) 858 { 859 struct resource *res; 860 resource_size_t n; 861 int k = 0, ret; 862 863 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) { 864 for (n = res->start; n <= res->end; n++) { 865 ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr, 866 0, dev_name(&dev->dev), pd); 867 if (ret) { 868 dev_err(&dev->dev, "cannot request IRQ %pa\n", &n); 869 return ret; 870 } 871 } 872 k++; 873 } 874 875 return k > 0 ? 0 : -ENOENT; 876 } 877 878 static int sh_mobile_i2c_probe(struct platform_device *dev) 879 { 880 struct i2c_sh_mobile_platform_data *pdata = dev_get_platdata(&dev->dev); 881 struct sh_mobile_i2c_data *pd; 882 struct i2c_adapter *adap; 883 struct resource *res; 884 int ret; 885 u32 bus_speed; 886 887 pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL); 888 if (!pd) 889 return -ENOMEM; 890 891 pd->clk = devm_clk_get(&dev->dev, NULL); 892 if (IS_ERR(pd->clk)) { 893 dev_err(&dev->dev, "cannot get clock\n"); 894 return PTR_ERR(pd->clk); 895 } 896 897 ret = sh_mobile_i2c_hook_irqs(dev, pd); 898 if (ret) 899 return ret; 900 901 pd->dev = &dev->dev; 902 platform_set_drvdata(dev, pd); 903 904 res = platform_get_resource(dev, IORESOURCE_MEM, 0); 905 906 pd->res = res; 907 pd->reg = devm_ioremap_resource(&dev->dev, res); 908 if (IS_ERR(pd->reg)) 909 return PTR_ERR(pd->reg); 910 911 /* Use platform data bus speed or STANDARD_MODE */ 912 ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed); 913 pd->bus_speed = ret ? STANDARD_MODE : bus_speed; 914 915 pd->clks_per_count = 1; 916 917 if (dev->dev.of_node) { 918 const struct of_device_id *match; 919 920 match = of_match_device(sh_mobile_i2c_dt_ids, &dev->dev); 921 if (match) { 922 const struct sh_mobile_dt_config *config; 923 924 config = match->data; 925 pd->clks_per_count = config->clks_per_count; 926 927 if (config->setup) 928 config->setup(pd); 929 } 930 } else { 931 if (pdata && pdata->bus_speed) 932 pd->bus_speed = pdata->bus_speed; 933 if (pdata && pdata->clks_per_count) 934 pd->clks_per_count = pdata->clks_per_count; 935 } 936 937 /* The IIC blocks on SH-Mobile ARM processors 938 * come with two new bits in ICIC. 939 */ 940 if (resource_size(res) > 0x17) 941 pd->flags |= IIC_FLAG_HAS_ICIC67; 942 943 ret = sh_mobile_i2c_init(pd); 944 if (ret) 945 return ret; 946 947 /* Init DMA */ 948 sg_init_table(&pd->sg, 1); 949 pd->dma_direction = DMA_NONE; 950 pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER); 951 952 /* Enable Runtime PM for this device. 953 * 954 * Also tell the Runtime PM core to ignore children 955 * for this device since it is valid for us to suspend 956 * this I2C master driver even though the slave devices 957 * on the I2C bus may not be suspended. 958 * 959 * The state of the I2C hardware bus is unaffected by 960 * the Runtime PM state. 961 */ 962 pm_suspend_ignore_children(&dev->dev, true); 963 pm_runtime_enable(&dev->dev); 964 965 /* setup the private data */ 966 adap = &pd->adap; 967 i2c_set_adapdata(adap, pd); 968 969 adap->owner = THIS_MODULE; 970 adap->algo = &sh_mobile_i2c_algorithm; 971 adap->dev.parent = &dev->dev; 972 adap->retries = 5; 973 adap->nr = dev->id; 974 adap->dev.of_node = dev->dev.of_node; 975 976 strlcpy(adap->name, dev->name, sizeof(adap->name)); 977 978 spin_lock_init(&pd->lock); 979 init_waitqueue_head(&pd->wait); 980 981 ret = i2c_add_numbered_adapter(adap); 982 if (ret < 0) { 983 sh_mobile_i2c_release_dma(pd); 984 dev_err(&dev->dev, "cannot add numbered adapter\n"); 985 return ret; 986 } 987 988 dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed); 989 990 return 0; 991 } 992 993 static int sh_mobile_i2c_remove(struct platform_device *dev) 994 { 995 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); 996 997 i2c_del_adapter(&pd->adap); 998 sh_mobile_i2c_release_dma(pd); 999 pm_runtime_disable(&dev->dev); 1000 return 0; 1001 } 1002 1003 static int sh_mobile_i2c_runtime_nop(struct device *dev) 1004 { 1005 /* Runtime PM callback shared between ->runtime_suspend() 1006 * and ->runtime_resume(). Simply returns success. 1007 * 1008 * This driver re-initializes all registers after 1009 * pm_runtime_get_sync() anyway so there is no need 1010 * to save and restore registers here. 1011 */ 1012 return 0; 1013 } 1014 1015 static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = { 1016 .runtime_suspend = sh_mobile_i2c_runtime_nop, 1017 .runtime_resume = sh_mobile_i2c_runtime_nop, 1018 }; 1019 1020 static struct platform_driver sh_mobile_i2c_driver = { 1021 .driver = { 1022 .name = "i2c-sh_mobile", 1023 .pm = &sh_mobile_i2c_dev_pm_ops, 1024 .of_match_table = sh_mobile_i2c_dt_ids, 1025 }, 1026 .probe = sh_mobile_i2c_probe, 1027 .remove = sh_mobile_i2c_remove, 1028 }; 1029 1030 static int __init sh_mobile_i2c_adap_init(void) 1031 { 1032 return platform_driver_register(&sh_mobile_i2c_driver); 1033 } 1034 subsys_initcall(sh_mobile_i2c_adap_init); 1035 1036 static void __exit sh_mobile_i2c_adap_exit(void) 1037 { 1038 platform_driver_unregister(&sh_mobile_i2c_driver); 1039 } 1040 module_exit(sh_mobile_i2c_adap_exit); 1041 1042 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver"); 1043 MODULE_AUTHOR("Magnus Damm and Wolfram Sang"); 1044 MODULE_LICENSE("GPL v2"); 1045 MODULE_ALIAS("platform:i2c-sh_mobile"); 1046