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