1 /* 2 * i2c-xiic.c 3 * Copyright (c) 2002-2007 Xilinx Inc. 4 * Copyright (c) 2009-2010 Intel Corporation 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * 16 * This code was implemented by Mocean Laboratories AB when porting linux 17 * to the automotive development board Russellville. The copyright holder 18 * as seen in the header is Intel corporation. 19 * Mocean Laboratories forked off the GNU/Linux platform work into a 20 * separate company called Pelagicore AB, which committed the code to the 21 * kernel. 22 */ 23 24 /* Supports: 25 * Xilinx IIC 26 */ 27 #include <linux/kernel.h> 28 #include <linux/module.h> 29 #include <linux/errno.h> 30 #include <linux/err.h> 31 #include <linux/delay.h> 32 #include <linux/platform_device.h> 33 #include <linux/i2c.h> 34 #include <linux/interrupt.h> 35 #include <linux/wait.h> 36 #include <linux/i2c-xiic.h> 37 #include <linux/io.h> 38 #include <linux/slab.h> 39 #include <linux/of.h> 40 #include <linux/clk.h> 41 #include <linux/pm_runtime.h> 42 43 #define DRIVER_NAME "xiic-i2c" 44 45 enum xilinx_i2c_state { 46 STATE_DONE, 47 STATE_ERROR, 48 STATE_START 49 }; 50 51 enum xiic_endian { 52 LITTLE, 53 BIG 54 }; 55 56 /** 57 * struct xiic_i2c - Internal representation of the XIIC I2C bus 58 * @base: Memory base of the HW registers 59 * @wait: Wait queue for callers 60 * @adap: Kernel adapter representation 61 * @tx_msg: Messages from above to be sent 62 * @lock: Mutual exclusion 63 * @tx_pos: Current pos in TX message 64 * @nmsgs: Number of messages in tx_msg 65 * @state: See STATE_ 66 * @rx_msg: Current RX message 67 * @rx_pos: Position within current RX message 68 * @endianness: big/little-endian byte order 69 */ 70 struct xiic_i2c { 71 struct device *dev; 72 void __iomem *base; 73 wait_queue_head_t wait; 74 struct i2c_adapter adap; 75 struct i2c_msg *tx_msg; 76 struct mutex lock; 77 unsigned int tx_pos; 78 unsigned int nmsgs; 79 enum xilinx_i2c_state state; 80 struct i2c_msg *rx_msg; 81 int rx_pos; 82 enum xiic_endian endianness; 83 struct clk *clk; 84 }; 85 86 87 #define XIIC_MSB_OFFSET 0 88 #define XIIC_REG_OFFSET (0x100+XIIC_MSB_OFFSET) 89 90 /* 91 * Register offsets in bytes from RegisterBase. Three is added to the 92 * base offset to access LSB (IBM style) of the word 93 */ 94 #define XIIC_CR_REG_OFFSET (0x00+XIIC_REG_OFFSET) /* Control Register */ 95 #define XIIC_SR_REG_OFFSET (0x04+XIIC_REG_OFFSET) /* Status Register */ 96 #define XIIC_DTR_REG_OFFSET (0x08+XIIC_REG_OFFSET) /* Data Tx Register */ 97 #define XIIC_DRR_REG_OFFSET (0x0C+XIIC_REG_OFFSET) /* Data Rx Register */ 98 #define XIIC_ADR_REG_OFFSET (0x10+XIIC_REG_OFFSET) /* Address Register */ 99 #define XIIC_TFO_REG_OFFSET (0x14+XIIC_REG_OFFSET) /* Tx FIFO Occupancy */ 100 #define XIIC_RFO_REG_OFFSET (0x18+XIIC_REG_OFFSET) /* Rx FIFO Occupancy */ 101 #define XIIC_TBA_REG_OFFSET (0x1C+XIIC_REG_OFFSET) /* 10 Bit Address reg */ 102 #define XIIC_RFD_REG_OFFSET (0x20+XIIC_REG_OFFSET) /* Rx FIFO Depth reg */ 103 #define XIIC_GPO_REG_OFFSET (0x24+XIIC_REG_OFFSET) /* Output Register */ 104 105 /* Control Register masks */ 106 #define XIIC_CR_ENABLE_DEVICE_MASK 0x01 /* Device enable = 1 */ 107 #define XIIC_CR_TX_FIFO_RESET_MASK 0x02 /* Transmit FIFO reset=1 */ 108 #define XIIC_CR_MSMS_MASK 0x04 /* Master starts Txing=1 */ 109 #define XIIC_CR_DIR_IS_TX_MASK 0x08 /* Dir of tx. Txing=1 */ 110 #define XIIC_CR_NO_ACK_MASK 0x10 /* Tx Ack. NO ack = 1 */ 111 #define XIIC_CR_REPEATED_START_MASK 0x20 /* Repeated start = 1 */ 112 #define XIIC_CR_GENERAL_CALL_MASK 0x40 /* Gen Call enabled = 1 */ 113 114 /* Status Register masks */ 115 #define XIIC_SR_GEN_CALL_MASK 0x01 /* 1=a mstr issued a GC */ 116 #define XIIC_SR_ADDR_AS_SLAVE_MASK 0x02 /* 1=when addr as slave */ 117 #define XIIC_SR_BUS_BUSY_MASK 0x04 /* 1 = bus is busy */ 118 #define XIIC_SR_MSTR_RDING_SLAVE_MASK 0x08 /* 1=Dir: mstr <-- slave */ 119 #define XIIC_SR_TX_FIFO_FULL_MASK 0x10 /* 1 = Tx FIFO full */ 120 #define XIIC_SR_RX_FIFO_FULL_MASK 0x20 /* 1 = Rx FIFO full */ 121 #define XIIC_SR_RX_FIFO_EMPTY_MASK 0x40 /* 1 = Rx FIFO empty */ 122 #define XIIC_SR_TX_FIFO_EMPTY_MASK 0x80 /* 1 = Tx FIFO empty */ 123 124 /* Interrupt Status Register masks Interrupt occurs when... */ 125 #define XIIC_INTR_ARB_LOST_MASK 0x01 /* 1 = arbitration lost */ 126 #define XIIC_INTR_TX_ERROR_MASK 0x02 /* 1=Tx error/msg complete */ 127 #define XIIC_INTR_TX_EMPTY_MASK 0x04 /* 1 = Tx FIFO/reg empty */ 128 #define XIIC_INTR_RX_FULL_MASK 0x08 /* 1=Rx FIFO/reg=OCY level */ 129 #define XIIC_INTR_BNB_MASK 0x10 /* 1 = Bus not busy */ 130 #define XIIC_INTR_AAS_MASK 0x20 /* 1 = when addr as slave */ 131 #define XIIC_INTR_NAAS_MASK 0x40 /* 1 = not addr as slave */ 132 #define XIIC_INTR_TX_HALF_MASK 0x80 /* 1 = TX FIFO half empty */ 133 134 /* The following constants specify the depth of the FIFOs */ 135 #define IIC_RX_FIFO_DEPTH 16 /* Rx fifo capacity */ 136 #define IIC_TX_FIFO_DEPTH 16 /* Tx fifo capacity */ 137 138 /* The following constants specify groups of interrupts that are typically 139 * enabled or disables at the same time 140 */ 141 #define XIIC_TX_INTERRUPTS \ 142 (XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK) 143 144 #define XIIC_TX_RX_INTERRUPTS (XIIC_INTR_RX_FULL_MASK | XIIC_TX_INTERRUPTS) 145 146 /* The following constants are used with the following macros to specify the 147 * operation, a read or write operation. 148 */ 149 #define XIIC_READ_OPERATION 1 150 #define XIIC_WRITE_OPERATION 0 151 152 /* 153 * Tx Fifo upper bit masks. 154 */ 155 #define XIIC_TX_DYN_START_MASK 0x0100 /* 1 = Set dynamic start */ 156 #define XIIC_TX_DYN_STOP_MASK 0x0200 /* 1 = Set dynamic stop */ 157 158 /* 159 * The following constants define the register offsets for the Interrupt 160 * registers. There are some holes in the memory map for reserved addresses 161 * to allow other registers to be added and still match the memory map of the 162 * interrupt controller registers 163 */ 164 #define XIIC_DGIER_OFFSET 0x1C /* Device Global Interrupt Enable Register */ 165 #define XIIC_IISR_OFFSET 0x20 /* Interrupt Status Register */ 166 #define XIIC_IIER_OFFSET 0x28 /* Interrupt Enable Register */ 167 #define XIIC_RESETR_OFFSET 0x40 /* Reset Register */ 168 169 #define XIIC_RESET_MASK 0xAUL 170 171 #define XIIC_PM_TIMEOUT 1000 /* ms */ 172 /* 173 * The following constant is used for the device global interrupt enable 174 * register, to enable all interrupts for the device, this is the only bit 175 * in the register 176 */ 177 #define XIIC_GINTR_ENABLE_MASK 0x80000000UL 178 179 #define xiic_tx_space(i2c) ((i2c)->tx_msg->len - (i2c)->tx_pos) 180 #define xiic_rx_space(i2c) ((i2c)->rx_msg->len - (i2c)->rx_pos) 181 182 static void xiic_start_xfer(struct xiic_i2c *i2c); 183 static void __xiic_start_xfer(struct xiic_i2c *i2c); 184 185 /* 186 * For the register read and write functions, a little-endian and big-endian 187 * version are necessary. Endianness is detected during the probe function. 188 * Only the least significant byte [doublet] of the register are ever 189 * accessed. This requires an offset of 3 [2] from the base address for 190 * big-endian systems. 191 */ 192 193 static inline void xiic_setreg8(struct xiic_i2c *i2c, int reg, u8 value) 194 { 195 if (i2c->endianness == LITTLE) 196 iowrite8(value, i2c->base + reg); 197 else 198 iowrite8(value, i2c->base + reg + 3); 199 } 200 201 static inline u8 xiic_getreg8(struct xiic_i2c *i2c, int reg) 202 { 203 u8 ret; 204 205 if (i2c->endianness == LITTLE) 206 ret = ioread8(i2c->base + reg); 207 else 208 ret = ioread8(i2c->base + reg + 3); 209 return ret; 210 } 211 212 static inline void xiic_setreg16(struct xiic_i2c *i2c, int reg, u16 value) 213 { 214 if (i2c->endianness == LITTLE) 215 iowrite16(value, i2c->base + reg); 216 else 217 iowrite16be(value, i2c->base + reg + 2); 218 } 219 220 static inline void xiic_setreg32(struct xiic_i2c *i2c, int reg, int value) 221 { 222 if (i2c->endianness == LITTLE) 223 iowrite32(value, i2c->base + reg); 224 else 225 iowrite32be(value, i2c->base + reg); 226 } 227 228 static inline int xiic_getreg32(struct xiic_i2c *i2c, int reg) 229 { 230 u32 ret; 231 232 if (i2c->endianness == LITTLE) 233 ret = ioread32(i2c->base + reg); 234 else 235 ret = ioread32be(i2c->base + reg); 236 return ret; 237 } 238 239 static inline void xiic_irq_dis(struct xiic_i2c *i2c, u32 mask) 240 { 241 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); 242 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier & ~mask); 243 } 244 245 static inline void xiic_irq_en(struct xiic_i2c *i2c, u32 mask) 246 { 247 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); 248 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier | mask); 249 } 250 251 static inline void xiic_irq_clr(struct xiic_i2c *i2c, u32 mask) 252 { 253 u32 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); 254 xiic_setreg32(i2c, XIIC_IISR_OFFSET, isr & mask); 255 } 256 257 static inline void xiic_irq_clr_en(struct xiic_i2c *i2c, u32 mask) 258 { 259 xiic_irq_clr(i2c, mask); 260 xiic_irq_en(i2c, mask); 261 } 262 263 static void xiic_clear_rx_fifo(struct xiic_i2c *i2c) 264 { 265 u8 sr; 266 for (sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET); 267 !(sr & XIIC_SR_RX_FIFO_EMPTY_MASK); 268 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET)) 269 xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET); 270 } 271 272 static void xiic_reinit(struct xiic_i2c *i2c) 273 { 274 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK); 275 276 /* Set receive Fifo depth to maximum (zero based). */ 277 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, IIC_RX_FIFO_DEPTH - 1); 278 279 /* Reset Tx Fifo. */ 280 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK); 281 282 /* Enable IIC Device, remove Tx Fifo reset & disable general call. */ 283 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_ENABLE_DEVICE_MASK); 284 285 /* make sure RX fifo is empty */ 286 xiic_clear_rx_fifo(i2c); 287 288 /* Enable interrupts */ 289 xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); 290 291 xiic_irq_clr_en(i2c, XIIC_INTR_ARB_LOST_MASK); 292 } 293 294 static void xiic_deinit(struct xiic_i2c *i2c) 295 { 296 u8 cr; 297 298 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK); 299 300 /* Disable IIC Device. */ 301 cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); 302 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_ENABLE_DEVICE_MASK); 303 } 304 305 static void xiic_read_rx(struct xiic_i2c *i2c) 306 { 307 u8 bytes_in_fifo; 308 int i; 309 310 bytes_in_fifo = xiic_getreg8(i2c, XIIC_RFO_REG_OFFSET) + 1; 311 312 dev_dbg(i2c->adap.dev.parent, 313 "%s entry, bytes in fifo: %d, msg: %d, SR: 0x%x, CR: 0x%x\n", 314 __func__, bytes_in_fifo, xiic_rx_space(i2c), 315 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET), 316 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); 317 318 if (bytes_in_fifo > xiic_rx_space(i2c)) 319 bytes_in_fifo = xiic_rx_space(i2c); 320 321 for (i = 0; i < bytes_in_fifo; i++) 322 i2c->rx_msg->buf[i2c->rx_pos++] = 323 xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET); 324 325 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, 326 (xiic_rx_space(i2c) > IIC_RX_FIFO_DEPTH) ? 327 IIC_RX_FIFO_DEPTH - 1 : xiic_rx_space(i2c) - 1); 328 } 329 330 static int xiic_tx_fifo_space(struct xiic_i2c *i2c) 331 { 332 /* return the actual space left in the FIFO */ 333 return IIC_TX_FIFO_DEPTH - xiic_getreg8(i2c, XIIC_TFO_REG_OFFSET) - 1; 334 } 335 336 static void xiic_fill_tx_fifo(struct xiic_i2c *i2c) 337 { 338 u8 fifo_space = xiic_tx_fifo_space(i2c); 339 int len = xiic_tx_space(i2c); 340 341 len = (len > fifo_space) ? fifo_space : len; 342 343 dev_dbg(i2c->adap.dev.parent, "%s entry, len: %d, fifo space: %d\n", 344 __func__, len, fifo_space); 345 346 while (len--) { 347 u16 data = i2c->tx_msg->buf[i2c->tx_pos++]; 348 if ((xiic_tx_space(i2c) == 0) && (i2c->nmsgs == 1)) { 349 /* last message in transfer -> STOP */ 350 data |= XIIC_TX_DYN_STOP_MASK; 351 dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__); 352 } 353 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); 354 } 355 } 356 357 static void xiic_wakeup(struct xiic_i2c *i2c, int code) 358 { 359 i2c->tx_msg = NULL; 360 i2c->rx_msg = NULL; 361 i2c->nmsgs = 0; 362 i2c->state = code; 363 wake_up(&i2c->wait); 364 } 365 366 static irqreturn_t xiic_process(int irq, void *dev_id) 367 { 368 struct xiic_i2c *i2c = dev_id; 369 u32 pend, isr, ier; 370 u32 clr = 0; 371 372 /* Get the interrupt Status from the IPIF. There is no clearing of 373 * interrupts in the IPIF. Interrupts must be cleared at the source. 374 * To find which interrupts are pending; AND interrupts pending with 375 * interrupts masked. 376 */ 377 mutex_lock(&i2c->lock); 378 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); 379 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); 380 pend = isr & ier; 381 382 dev_dbg(i2c->adap.dev.parent, "%s: IER: 0x%x, ISR: 0x%x, pend: 0x%x\n", 383 __func__, ier, isr, pend); 384 dev_dbg(i2c->adap.dev.parent, "%s: SR: 0x%x, msg: %p, nmsgs: %d\n", 385 __func__, xiic_getreg8(i2c, XIIC_SR_REG_OFFSET), 386 i2c->tx_msg, i2c->nmsgs); 387 388 389 /* Service requesting interrupt */ 390 if ((pend & XIIC_INTR_ARB_LOST_MASK) || 391 ((pend & XIIC_INTR_TX_ERROR_MASK) && 392 !(pend & XIIC_INTR_RX_FULL_MASK))) { 393 /* bus arbritration lost, or... 394 * Transmit error _OR_ RX completed 395 * if this happens when RX_FULL is not set 396 * this is probably a TX error 397 */ 398 399 dev_dbg(i2c->adap.dev.parent, "%s error\n", __func__); 400 401 /* dynamic mode seem to suffer from problems if we just flushes 402 * fifos and the next message is a TX with len 0 (only addr) 403 * reset the IP instead of just flush fifos 404 */ 405 xiic_reinit(i2c); 406 407 if (i2c->rx_msg) 408 xiic_wakeup(i2c, STATE_ERROR); 409 if (i2c->tx_msg) 410 xiic_wakeup(i2c, STATE_ERROR); 411 } 412 if (pend & XIIC_INTR_RX_FULL_MASK) { 413 /* Receive register/FIFO is full */ 414 415 clr |= XIIC_INTR_RX_FULL_MASK; 416 if (!i2c->rx_msg) { 417 dev_dbg(i2c->adap.dev.parent, 418 "%s unexpexted RX IRQ\n", __func__); 419 xiic_clear_rx_fifo(i2c); 420 goto out; 421 } 422 423 xiic_read_rx(i2c); 424 if (xiic_rx_space(i2c) == 0) { 425 /* this is the last part of the message */ 426 i2c->rx_msg = NULL; 427 428 /* also clear TX error if there (RX complete) */ 429 clr |= (isr & XIIC_INTR_TX_ERROR_MASK); 430 431 dev_dbg(i2c->adap.dev.parent, 432 "%s end of message, nmsgs: %d\n", 433 __func__, i2c->nmsgs); 434 435 /* send next message if this wasn't the last, 436 * otherwise the transfer will be finialise when 437 * receiving the bus not busy interrupt 438 */ 439 if (i2c->nmsgs > 1) { 440 i2c->nmsgs--; 441 i2c->tx_msg++; 442 dev_dbg(i2c->adap.dev.parent, 443 "%s will start next...\n", __func__); 444 445 __xiic_start_xfer(i2c); 446 } 447 } 448 } 449 if (pend & XIIC_INTR_BNB_MASK) { 450 /* IIC bus has transitioned to not busy */ 451 clr |= XIIC_INTR_BNB_MASK; 452 453 /* The bus is not busy, disable BusNotBusy interrupt */ 454 xiic_irq_dis(i2c, XIIC_INTR_BNB_MASK); 455 456 if (!i2c->tx_msg) 457 goto out; 458 459 if ((i2c->nmsgs == 1) && !i2c->rx_msg && 460 xiic_tx_space(i2c) == 0) 461 xiic_wakeup(i2c, STATE_DONE); 462 else 463 xiic_wakeup(i2c, STATE_ERROR); 464 } 465 if (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)) { 466 /* Transmit register/FIFO is empty or ½ empty */ 467 468 clr |= (pend & 469 (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)); 470 471 if (!i2c->tx_msg) { 472 dev_dbg(i2c->adap.dev.parent, 473 "%s unexpexted TX IRQ\n", __func__); 474 goto out; 475 } 476 477 xiic_fill_tx_fifo(i2c); 478 479 /* current message sent and there is space in the fifo */ 480 if (!xiic_tx_space(i2c) && xiic_tx_fifo_space(i2c) >= 2) { 481 dev_dbg(i2c->adap.dev.parent, 482 "%s end of message sent, nmsgs: %d\n", 483 __func__, i2c->nmsgs); 484 if (i2c->nmsgs > 1) { 485 i2c->nmsgs--; 486 i2c->tx_msg++; 487 __xiic_start_xfer(i2c); 488 } else { 489 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK); 490 491 dev_dbg(i2c->adap.dev.parent, 492 "%s Got TX IRQ but no more to do...\n", 493 __func__); 494 } 495 } else if (!xiic_tx_space(i2c) && (i2c->nmsgs == 1)) 496 /* current frame is sent and is last, 497 * make sure to disable tx half 498 */ 499 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK); 500 } 501 out: 502 dev_dbg(i2c->adap.dev.parent, "%s clr: 0x%x\n", __func__, clr); 503 504 xiic_setreg32(i2c, XIIC_IISR_OFFSET, clr); 505 mutex_unlock(&i2c->lock); 506 return IRQ_HANDLED; 507 } 508 509 static int xiic_bus_busy(struct xiic_i2c *i2c) 510 { 511 u8 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET); 512 513 return (sr & XIIC_SR_BUS_BUSY_MASK) ? -EBUSY : 0; 514 } 515 516 static int xiic_busy(struct xiic_i2c *i2c) 517 { 518 int tries = 3; 519 int err; 520 521 if (i2c->tx_msg) 522 return -EBUSY; 523 524 /* for instance if previous transfer was terminated due to TX error 525 * it might be that the bus is on it's way to become available 526 * give it at most 3 ms to wake 527 */ 528 err = xiic_bus_busy(i2c); 529 while (err && tries--) { 530 msleep(1); 531 err = xiic_bus_busy(i2c); 532 } 533 534 return err; 535 } 536 537 static void xiic_start_recv(struct xiic_i2c *i2c) 538 { 539 u8 rx_watermark; 540 struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg; 541 542 /* Clear and enable Rx full interrupt. */ 543 xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK); 544 545 /* we want to get all but last byte, because the TX_ERROR IRQ is used 546 * to inidicate error ACK on the address, and negative ack on the last 547 * received byte, so to not mix them receive all but last. 548 * In the case where there is only one byte to receive 549 * we can check if ERROR and RX full is set at the same time 550 */ 551 rx_watermark = msg->len; 552 if (rx_watermark > IIC_RX_FIFO_DEPTH) 553 rx_watermark = IIC_RX_FIFO_DEPTH; 554 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rx_watermark - 1); 555 556 if (!(msg->flags & I2C_M_NOSTART)) 557 /* write the address */ 558 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, 559 (msg->addr << 1) | XIIC_READ_OPERATION | 560 XIIC_TX_DYN_START_MASK); 561 562 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); 563 564 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, 565 msg->len | ((i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0)); 566 if (i2c->nmsgs == 1) 567 /* very last, enable bus not busy as well */ 568 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); 569 570 /* the message is tx:ed */ 571 i2c->tx_pos = msg->len; 572 } 573 574 static void xiic_start_send(struct xiic_i2c *i2c) 575 { 576 struct i2c_msg *msg = i2c->tx_msg; 577 578 xiic_irq_clr(i2c, XIIC_INTR_TX_ERROR_MASK); 579 580 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, len: %d", 581 __func__, msg, msg->len); 582 dev_dbg(i2c->adap.dev.parent, "%s entry, ISR: 0x%x, CR: 0x%x\n", 583 __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), 584 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); 585 586 if (!(msg->flags & I2C_M_NOSTART)) { 587 /* write the address */ 588 u16 data = ((msg->addr << 1) & 0xfe) | XIIC_WRITE_OPERATION | 589 XIIC_TX_DYN_START_MASK; 590 if ((i2c->nmsgs == 1) && msg->len == 0) 591 /* no data and last message -> add STOP */ 592 data |= XIIC_TX_DYN_STOP_MASK; 593 594 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); 595 } 596 597 xiic_fill_tx_fifo(i2c); 598 599 /* Clear any pending Tx empty, Tx Error and then enable them. */ 600 xiic_irq_clr_en(i2c, XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_ERROR_MASK | 601 XIIC_INTR_BNB_MASK); 602 } 603 604 static irqreturn_t xiic_isr(int irq, void *dev_id) 605 { 606 struct xiic_i2c *i2c = dev_id; 607 u32 pend, isr, ier; 608 irqreturn_t ret = IRQ_NONE; 609 /* Do not processes a devices interrupts if the device has no 610 * interrupts pending 611 */ 612 613 dev_dbg(i2c->adap.dev.parent, "%s entry\n", __func__); 614 615 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); 616 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); 617 pend = isr & ier; 618 if (pend) 619 ret = IRQ_WAKE_THREAD; 620 621 return ret; 622 } 623 624 static void __xiic_start_xfer(struct xiic_i2c *i2c) 625 { 626 int first = 1; 627 int fifo_space = xiic_tx_fifo_space(i2c); 628 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, fifos space: %d\n", 629 __func__, i2c->tx_msg, fifo_space); 630 631 if (!i2c->tx_msg) 632 return; 633 634 i2c->rx_pos = 0; 635 i2c->tx_pos = 0; 636 i2c->state = STATE_START; 637 while ((fifo_space >= 2) && (first || (i2c->nmsgs > 1))) { 638 if (!first) { 639 i2c->nmsgs--; 640 i2c->tx_msg++; 641 i2c->tx_pos = 0; 642 } else 643 first = 0; 644 645 if (i2c->tx_msg->flags & I2C_M_RD) { 646 /* we dont date putting several reads in the FIFO */ 647 xiic_start_recv(i2c); 648 return; 649 } else { 650 xiic_start_send(i2c); 651 if (xiic_tx_space(i2c) != 0) { 652 /* the message could not be completely sent */ 653 break; 654 } 655 } 656 657 fifo_space = xiic_tx_fifo_space(i2c); 658 } 659 660 /* there are more messages or the current one could not be completely 661 * put into the FIFO, also enable the half empty interrupt 662 */ 663 if (i2c->nmsgs > 1 || xiic_tx_space(i2c)) 664 xiic_irq_clr_en(i2c, XIIC_INTR_TX_HALF_MASK); 665 666 } 667 668 static void xiic_start_xfer(struct xiic_i2c *i2c) 669 { 670 mutex_lock(&i2c->lock); 671 xiic_reinit(i2c); 672 __xiic_start_xfer(i2c); 673 mutex_unlock(&i2c->lock); 674 } 675 676 static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 677 { 678 struct xiic_i2c *i2c = i2c_get_adapdata(adap); 679 int err; 680 681 dev_dbg(adap->dev.parent, "%s entry SR: 0x%x\n", __func__, 682 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET)); 683 684 err = pm_runtime_get_sync(i2c->dev); 685 if (err < 0) 686 return err; 687 688 err = xiic_busy(i2c); 689 if (err) 690 goto out; 691 692 i2c->tx_msg = msgs; 693 i2c->nmsgs = num; 694 695 xiic_start_xfer(i2c); 696 697 if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) || 698 (i2c->state == STATE_DONE), HZ)) { 699 err = (i2c->state == STATE_DONE) ? num : -EIO; 700 goto out; 701 } else { 702 i2c->tx_msg = NULL; 703 i2c->rx_msg = NULL; 704 i2c->nmsgs = 0; 705 err = -ETIMEDOUT; 706 goto out; 707 } 708 out: 709 pm_runtime_mark_last_busy(i2c->dev); 710 pm_runtime_put_autosuspend(i2c->dev); 711 return err; 712 } 713 714 static u32 xiic_func(struct i2c_adapter *adap) 715 { 716 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; 717 } 718 719 static const struct i2c_algorithm xiic_algorithm = { 720 .master_xfer = xiic_xfer, 721 .functionality = xiic_func, 722 }; 723 724 static const struct i2c_adapter xiic_adapter = { 725 .owner = THIS_MODULE, 726 .name = DRIVER_NAME, 727 .class = I2C_CLASS_DEPRECATED, 728 .algo = &xiic_algorithm, 729 }; 730 731 732 static int xiic_i2c_probe(struct platform_device *pdev) 733 { 734 struct xiic_i2c *i2c; 735 struct xiic_i2c_platform_data *pdata; 736 struct resource *res; 737 int ret, irq; 738 u8 i; 739 u32 sr; 740 741 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); 742 if (!i2c) 743 return -ENOMEM; 744 745 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 746 i2c->base = devm_ioremap_resource(&pdev->dev, res); 747 if (IS_ERR(i2c->base)) 748 return PTR_ERR(i2c->base); 749 750 irq = platform_get_irq(pdev, 0); 751 if (irq < 0) 752 return irq; 753 754 pdata = dev_get_platdata(&pdev->dev); 755 756 /* hook up driver to tree */ 757 platform_set_drvdata(pdev, i2c); 758 i2c->adap = xiic_adapter; 759 i2c_set_adapdata(&i2c->adap, i2c); 760 i2c->adap.dev.parent = &pdev->dev; 761 i2c->adap.dev.of_node = pdev->dev.of_node; 762 763 mutex_init(&i2c->lock); 764 init_waitqueue_head(&i2c->wait); 765 766 i2c->clk = devm_clk_get(&pdev->dev, NULL); 767 if (IS_ERR(i2c->clk)) { 768 dev_err(&pdev->dev, "input clock not found.\n"); 769 return PTR_ERR(i2c->clk); 770 } 771 ret = clk_prepare_enable(i2c->clk); 772 if (ret) { 773 dev_err(&pdev->dev, "Unable to enable clock.\n"); 774 return ret; 775 } 776 i2c->dev = &pdev->dev; 777 pm_runtime_enable(i2c->dev); 778 pm_runtime_set_autosuspend_delay(i2c->dev, XIIC_PM_TIMEOUT); 779 pm_runtime_use_autosuspend(i2c->dev); 780 pm_runtime_set_active(i2c->dev); 781 ret = devm_request_threaded_irq(&pdev->dev, irq, xiic_isr, 782 xiic_process, IRQF_ONESHOT, 783 pdev->name, i2c); 784 785 if (ret < 0) { 786 dev_err(&pdev->dev, "Cannot claim IRQ\n"); 787 goto err_clk_dis; 788 } 789 790 /* 791 * Detect endianness 792 * Try to reset the TX FIFO. Then check the EMPTY flag. If it is not 793 * set, assume that the endianness was wrong and swap. 794 */ 795 i2c->endianness = LITTLE; 796 xiic_setreg32(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK); 797 /* Reset is cleared in xiic_reinit */ 798 sr = xiic_getreg32(i2c, XIIC_SR_REG_OFFSET); 799 if (!(sr & XIIC_SR_TX_FIFO_EMPTY_MASK)) 800 i2c->endianness = BIG; 801 802 xiic_reinit(i2c); 803 804 /* add i2c adapter to i2c tree */ 805 ret = i2c_add_adapter(&i2c->adap); 806 if (ret) { 807 xiic_deinit(i2c); 808 goto err_clk_dis; 809 } 810 811 if (pdata) { 812 /* add in known devices to the bus */ 813 for (i = 0; i < pdata->num_devices; i++) 814 i2c_new_device(&i2c->adap, pdata->devices + i); 815 } 816 817 return 0; 818 819 err_clk_dis: 820 pm_runtime_set_suspended(&pdev->dev); 821 pm_runtime_disable(&pdev->dev); 822 clk_disable_unprepare(i2c->clk); 823 return ret; 824 } 825 826 static int xiic_i2c_remove(struct platform_device *pdev) 827 { 828 struct xiic_i2c *i2c = platform_get_drvdata(pdev); 829 int ret; 830 831 /* remove adapter & data */ 832 i2c_del_adapter(&i2c->adap); 833 834 ret = clk_prepare_enable(i2c->clk); 835 if (ret) { 836 dev_err(&pdev->dev, "Unable to enable clock.\n"); 837 return ret; 838 } 839 xiic_deinit(i2c); 840 clk_disable_unprepare(i2c->clk); 841 pm_runtime_disable(&pdev->dev); 842 843 return 0; 844 } 845 846 #if defined(CONFIG_OF) 847 static const struct of_device_id xiic_of_match[] = { 848 { .compatible = "xlnx,xps-iic-2.00.a", }, 849 {}, 850 }; 851 MODULE_DEVICE_TABLE(of, xiic_of_match); 852 #endif 853 854 static int __maybe_unused xiic_i2c_runtime_suspend(struct device *dev) 855 { 856 struct xiic_i2c *i2c = dev_get_drvdata(dev); 857 858 clk_disable(i2c->clk); 859 860 return 0; 861 } 862 863 static int __maybe_unused xiic_i2c_runtime_resume(struct device *dev) 864 { 865 struct xiic_i2c *i2c = dev_get_drvdata(dev); 866 int ret; 867 868 ret = clk_enable(i2c->clk); 869 if (ret) { 870 dev_err(dev, "Cannot enable clock.\n"); 871 return ret; 872 } 873 874 return 0; 875 } 876 877 static const struct dev_pm_ops xiic_dev_pm_ops = { 878 SET_RUNTIME_PM_OPS(xiic_i2c_runtime_suspend, 879 xiic_i2c_runtime_resume, NULL) 880 }; 881 static struct platform_driver xiic_i2c_driver = { 882 .probe = xiic_i2c_probe, 883 .remove = xiic_i2c_remove, 884 .driver = { 885 .name = DRIVER_NAME, 886 .of_match_table = of_match_ptr(xiic_of_match), 887 .pm = &xiic_dev_pm_ops, 888 }, 889 }; 890 891 module_platform_driver(xiic_i2c_driver); 892 893 MODULE_AUTHOR("info@mocean-labs.com"); 894 MODULE_DESCRIPTION("Xilinx I2C bus driver"); 895 MODULE_LICENSE("GPL v2"); 896 MODULE_ALIAS("platform:"DRIVER_NAME); 897