1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * i2c-xiic.c 4 * Copyright (c) 2002-2007 Xilinx Inc. 5 * Copyright (c) 2009-2010 Intel Corporation 6 * 7 * This code was implemented by Mocean Laboratories AB when porting linux 8 * to the automotive development board Russellville. The copyright holder 9 * as seen in the header is Intel corporation. 10 * Mocean Laboratories forked off the GNU/Linux platform work into a 11 * separate company called Pelagicore AB, which committed the code to the 12 * kernel. 13 */ 14 15 /* Supports: 16 * Xilinx IIC 17 */ 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/errno.h> 21 #include <linux/err.h> 22 #include <linux/delay.h> 23 #include <linux/platform_device.h> 24 #include <linux/i2c.h> 25 #include <linux/interrupt.h> 26 #include <linux/wait.h> 27 #include <linux/platform_data/i2c-xiic.h> 28 #include <linux/io.h> 29 #include <linux/slab.h> 30 #include <linux/of.h> 31 #include <linux/clk.h> 32 #include <linux/pm_runtime.h> 33 34 #define DRIVER_NAME "xiic-i2c" 35 36 enum xilinx_i2c_state { 37 STATE_DONE, 38 STATE_ERROR, 39 STATE_START 40 }; 41 42 enum xiic_endian { 43 LITTLE, 44 BIG 45 }; 46 47 /** 48 * struct xiic_i2c - Internal representation of the XIIC I2C bus 49 * @dev: Pointer to device structure 50 * @base: Memory base of the HW registers 51 * @wait: Wait queue for callers 52 * @adap: Kernel adapter representation 53 * @tx_msg: Messages from above to be sent 54 * @lock: Mutual exclusion 55 * @tx_pos: Current pos in TX message 56 * @nmsgs: Number of messages in tx_msg 57 * @rx_msg: Current RX message 58 * @rx_pos: Position within current RX message 59 * @endianness: big/little-endian byte order 60 * @clk: Pointer to AXI4-lite input clock 61 * @state: See STATE_ 62 * @singlemaster: Indicates bus is single master 63 */ 64 struct xiic_i2c { 65 struct device *dev; 66 void __iomem *base; 67 wait_queue_head_t wait; 68 struct i2c_adapter adap; 69 struct i2c_msg *tx_msg; 70 struct mutex lock; 71 unsigned int tx_pos; 72 unsigned int nmsgs; 73 struct i2c_msg *rx_msg; 74 int rx_pos; 75 enum xiic_endian endianness; 76 struct clk *clk; 77 enum xilinx_i2c_state state; 78 bool singlemaster; 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 /* 142 * Tx Fifo upper bit masks. 143 */ 144 #define XIIC_TX_DYN_START_MASK 0x0100 /* 1 = Set dynamic start */ 145 #define XIIC_TX_DYN_STOP_MASK 0x0200 /* 1 = Set dynamic stop */ 146 147 /* 148 * The following constants define the register offsets for the Interrupt 149 * registers. There are some holes in the memory map for reserved addresses 150 * to allow other registers to be added and still match the memory map of the 151 * interrupt controller registers 152 */ 153 #define XIIC_DGIER_OFFSET 0x1C /* Device Global Interrupt Enable Register */ 154 #define XIIC_IISR_OFFSET 0x20 /* Interrupt Status Register */ 155 #define XIIC_IIER_OFFSET 0x28 /* Interrupt Enable Register */ 156 #define XIIC_RESETR_OFFSET 0x40 /* Reset Register */ 157 158 #define XIIC_RESET_MASK 0xAUL 159 160 #define XIIC_PM_TIMEOUT 1000 /* ms */ 161 /* timeout waiting for the controller to respond */ 162 #define XIIC_I2C_TIMEOUT (msecs_to_jiffies(1000)) 163 /* 164 * The following constant is used for the device global interrupt enable 165 * register, to enable all interrupts for the device, this is the only bit 166 * in the register 167 */ 168 #define XIIC_GINTR_ENABLE_MASK 0x80000000UL 169 170 #define xiic_tx_space(i2c) ((i2c)->tx_msg->len - (i2c)->tx_pos) 171 #define xiic_rx_space(i2c) ((i2c)->rx_msg->len - (i2c)->rx_pos) 172 173 static int xiic_start_xfer(struct xiic_i2c *i2c); 174 static void __xiic_start_xfer(struct xiic_i2c *i2c); 175 176 /* 177 * For the register read and write functions, a little-endian and big-endian 178 * version are necessary. Endianness is detected during the probe function. 179 * Only the least significant byte [doublet] of the register are ever 180 * accessed. This requires an offset of 3 [2] from the base address for 181 * big-endian systems. 182 */ 183 184 static inline void xiic_setreg8(struct xiic_i2c *i2c, int reg, u8 value) 185 { 186 if (i2c->endianness == LITTLE) 187 iowrite8(value, i2c->base + reg); 188 else 189 iowrite8(value, i2c->base + reg + 3); 190 } 191 192 static inline u8 xiic_getreg8(struct xiic_i2c *i2c, int reg) 193 { 194 u8 ret; 195 196 if (i2c->endianness == LITTLE) 197 ret = ioread8(i2c->base + reg); 198 else 199 ret = ioread8(i2c->base + reg + 3); 200 return ret; 201 } 202 203 static inline void xiic_setreg16(struct xiic_i2c *i2c, int reg, u16 value) 204 { 205 if (i2c->endianness == LITTLE) 206 iowrite16(value, i2c->base + reg); 207 else 208 iowrite16be(value, i2c->base + reg + 2); 209 } 210 211 static inline void xiic_setreg32(struct xiic_i2c *i2c, int reg, int value) 212 { 213 if (i2c->endianness == LITTLE) 214 iowrite32(value, i2c->base + reg); 215 else 216 iowrite32be(value, i2c->base + reg); 217 } 218 219 static inline int xiic_getreg32(struct xiic_i2c *i2c, int reg) 220 { 221 u32 ret; 222 223 if (i2c->endianness == LITTLE) 224 ret = ioread32(i2c->base + reg); 225 else 226 ret = ioread32be(i2c->base + reg); 227 return ret; 228 } 229 230 static inline void xiic_irq_dis(struct xiic_i2c *i2c, u32 mask) 231 { 232 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); 233 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier & ~mask); 234 } 235 236 static inline void xiic_irq_en(struct xiic_i2c *i2c, u32 mask) 237 { 238 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); 239 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier | mask); 240 } 241 242 static inline void xiic_irq_clr(struct xiic_i2c *i2c, u32 mask) 243 { 244 u32 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); 245 xiic_setreg32(i2c, XIIC_IISR_OFFSET, isr & mask); 246 } 247 248 static inline void xiic_irq_clr_en(struct xiic_i2c *i2c, u32 mask) 249 { 250 xiic_irq_clr(i2c, mask); 251 xiic_irq_en(i2c, mask); 252 } 253 254 static int xiic_clear_rx_fifo(struct xiic_i2c *i2c) 255 { 256 u8 sr; 257 unsigned long timeout; 258 259 timeout = jiffies + XIIC_I2C_TIMEOUT; 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 if (time_after(jiffies, timeout)) { 265 dev_err(i2c->dev, "Failed to clear rx fifo\n"); 266 return -ETIMEDOUT; 267 } 268 } 269 270 return 0; 271 } 272 273 static int xiic_reinit(struct xiic_i2c *i2c) 274 { 275 int ret; 276 277 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK); 278 279 /* Set receive Fifo depth to maximum (zero based). */ 280 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, IIC_RX_FIFO_DEPTH - 1); 281 282 /* Reset Tx Fifo. */ 283 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK); 284 285 /* Enable IIC Device, remove Tx Fifo reset & disable general call. */ 286 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_ENABLE_DEVICE_MASK); 287 288 /* make sure RX fifo is empty */ 289 ret = xiic_clear_rx_fifo(i2c); 290 if (ret) 291 return ret; 292 293 /* Enable interrupts */ 294 xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); 295 296 xiic_irq_clr_en(i2c, XIIC_INTR_ARB_LOST_MASK); 297 298 return 0; 299 } 300 301 static void xiic_deinit(struct xiic_i2c *i2c) 302 { 303 u8 cr; 304 305 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK); 306 307 /* Disable IIC Device. */ 308 cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); 309 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_ENABLE_DEVICE_MASK); 310 } 311 312 static void xiic_read_rx(struct xiic_i2c *i2c) 313 { 314 u8 bytes_in_fifo; 315 int i; 316 317 bytes_in_fifo = xiic_getreg8(i2c, XIIC_RFO_REG_OFFSET) + 1; 318 319 dev_dbg(i2c->adap.dev.parent, 320 "%s entry, bytes in fifo: %d, msg: %d, SR: 0x%x, CR: 0x%x\n", 321 __func__, bytes_in_fifo, xiic_rx_space(i2c), 322 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET), 323 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); 324 325 if (bytes_in_fifo > xiic_rx_space(i2c)) 326 bytes_in_fifo = xiic_rx_space(i2c); 327 328 for (i = 0; i < bytes_in_fifo; i++) 329 i2c->rx_msg->buf[i2c->rx_pos++] = 330 xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET); 331 332 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, 333 (xiic_rx_space(i2c) > IIC_RX_FIFO_DEPTH) ? 334 IIC_RX_FIFO_DEPTH - 1 : xiic_rx_space(i2c) - 1); 335 } 336 337 static int xiic_tx_fifo_space(struct xiic_i2c *i2c) 338 { 339 /* return the actual space left in the FIFO */ 340 return IIC_TX_FIFO_DEPTH - xiic_getreg8(i2c, XIIC_TFO_REG_OFFSET) - 1; 341 } 342 343 static void xiic_fill_tx_fifo(struct xiic_i2c *i2c) 344 { 345 u8 fifo_space = xiic_tx_fifo_space(i2c); 346 int len = xiic_tx_space(i2c); 347 348 len = (len > fifo_space) ? fifo_space : len; 349 350 dev_dbg(i2c->adap.dev.parent, "%s entry, len: %d, fifo space: %d\n", 351 __func__, len, fifo_space); 352 353 while (len--) { 354 u16 data = i2c->tx_msg->buf[i2c->tx_pos++]; 355 if ((xiic_tx_space(i2c) == 0) && (i2c->nmsgs == 1)) { 356 /* last message in transfer -> STOP */ 357 data |= XIIC_TX_DYN_STOP_MASK; 358 dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__); 359 } 360 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); 361 } 362 } 363 364 static void xiic_wakeup(struct xiic_i2c *i2c, int code) 365 { 366 i2c->tx_msg = NULL; 367 i2c->rx_msg = NULL; 368 i2c->nmsgs = 0; 369 i2c->state = code; 370 wake_up(&i2c->wait); 371 } 372 373 static irqreturn_t xiic_process(int irq, void *dev_id) 374 { 375 struct xiic_i2c *i2c = dev_id; 376 u32 pend, isr, ier; 377 u32 clr = 0; 378 379 /* Get the interrupt Status from the IPIF. There is no clearing of 380 * interrupts in the IPIF. Interrupts must be cleared at the source. 381 * To find which interrupts are pending; AND interrupts pending with 382 * interrupts masked. 383 */ 384 mutex_lock(&i2c->lock); 385 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); 386 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); 387 pend = isr & ier; 388 389 dev_dbg(i2c->adap.dev.parent, "%s: IER: 0x%x, ISR: 0x%x, pend: 0x%x\n", 390 __func__, ier, isr, pend); 391 dev_dbg(i2c->adap.dev.parent, "%s: SR: 0x%x, msg: %p, nmsgs: %d\n", 392 __func__, xiic_getreg8(i2c, XIIC_SR_REG_OFFSET), 393 i2c->tx_msg, i2c->nmsgs); 394 395 396 /* Service requesting interrupt */ 397 if ((pend & XIIC_INTR_ARB_LOST_MASK) || 398 ((pend & XIIC_INTR_TX_ERROR_MASK) && 399 !(pend & XIIC_INTR_RX_FULL_MASK))) { 400 /* bus arbritration lost, or... 401 * Transmit error _OR_ RX completed 402 * if this happens when RX_FULL is not set 403 * this is probably a TX error 404 */ 405 406 dev_dbg(i2c->adap.dev.parent, "%s error\n", __func__); 407 408 /* dynamic mode seem to suffer from problems if we just flushes 409 * fifos and the next message is a TX with len 0 (only addr) 410 * reset the IP instead of just flush fifos 411 */ 412 xiic_reinit(i2c); 413 414 if (i2c->rx_msg) 415 xiic_wakeup(i2c, STATE_ERROR); 416 if (i2c->tx_msg) 417 xiic_wakeup(i2c, STATE_ERROR); 418 } 419 if (pend & XIIC_INTR_RX_FULL_MASK) { 420 /* Receive register/FIFO is full */ 421 422 clr |= XIIC_INTR_RX_FULL_MASK; 423 if (!i2c->rx_msg) { 424 dev_dbg(i2c->adap.dev.parent, 425 "%s unexpected RX IRQ\n", __func__); 426 xiic_clear_rx_fifo(i2c); 427 goto out; 428 } 429 430 xiic_read_rx(i2c); 431 if (xiic_rx_space(i2c) == 0) { 432 /* this is the last part of the message */ 433 i2c->rx_msg = NULL; 434 435 /* also clear TX error if there (RX complete) */ 436 clr |= (isr & XIIC_INTR_TX_ERROR_MASK); 437 438 dev_dbg(i2c->adap.dev.parent, 439 "%s end of message, nmsgs: %d\n", 440 __func__, i2c->nmsgs); 441 442 /* send next message if this wasn't the last, 443 * otherwise the transfer will be finialise when 444 * receiving the bus not busy interrupt 445 */ 446 if (i2c->nmsgs > 1) { 447 i2c->nmsgs--; 448 i2c->tx_msg++; 449 dev_dbg(i2c->adap.dev.parent, 450 "%s will start next...\n", __func__); 451 452 __xiic_start_xfer(i2c); 453 } 454 } 455 } 456 if (pend & XIIC_INTR_BNB_MASK) { 457 /* IIC bus has transitioned to not busy */ 458 clr |= XIIC_INTR_BNB_MASK; 459 460 /* The bus is not busy, disable BusNotBusy interrupt */ 461 xiic_irq_dis(i2c, XIIC_INTR_BNB_MASK); 462 463 if (!i2c->tx_msg) 464 goto out; 465 466 if ((i2c->nmsgs == 1) && !i2c->rx_msg && 467 xiic_tx_space(i2c) == 0) 468 xiic_wakeup(i2c, STATE_DONE); 469 else 470 xiic_wakeup(i2c, STATE_ERROR); 471 } 472 if (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)) { 473 /* Transmit register/FIFO is empty or ½ empty */ 474 475 clr |= (pend & 476 (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)); 477 478 if (!i2c->tx_msg) { 479 dev_dbg(i2c->adap.dev.parent, 480 "%s unexpected TX IRQ\n", __func__); 481 goto out; 482 } 483 484 xiic_fill_tx_fifo(i2c); 485 486 /* current message sent and there is space in the fifo */ 487 if (!xiic_tx_space(i2c) && xiic_tx_fifo_space(i2c) >= 2) { 488 dev_dbg(i2c->adap.dev.parent, 489 "%s end of message sent, nmsgs: %d\n", 490 __func__, i2c->nmsgs); 491 if (i2c->nmsgs > 1) { 492 i2c->nmsgs--; 493 i2c->tx_msg++; 494 __xiic_start_xfer(i2c); 495 } else { 496 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK); 497 498 dev_dbg(i2c->adap.dev.parent, 499 "%s Got TX IRQ but no more to do...\n", 500 __func__); 501 } 502 } else if (!xiic_tx_space(i2c) && (i2c->nmsgs == 1)) 503 /* current frame is sent and is last, 504 * make sure to disable tx half 505 */ 506 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK); 507 } 508 out: 509 dev_dbg(i2c->adap.dev.parent, "%s clr: 0x%x\n", __func__, clr); 510 511 xiic_setreg32(i2c, XIIC_IISR_OFFSET, clr); 512 mutex_unlock(&i2c->lock); 513 return IRQ_HANDLED; 514 } 515 516 static int xiic_bus_busy(struct xiic_i2c *i2c) 517 { 518 u8 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET); 519 520 return (sr & XIIC_SR_BUS_BUSY_MASK) ? -EBUSY : 0; 521 } 522 523 static int xiic_busy(struct xiic_i2c *i2c) 524 { 525 int tries = 3; 526 int err; 527 528 if (i2c->tx_msg) 529 return -EBUSY; 530 531 /* In single master mode bus can only be busy, when in use by this 532 * driver. If the register indicates bus being busy for some reason we 533 * should ignore it, since bus will never be released and i2c will be 534 * stuck forever. 535 */ 536 if (i2c->singlemaster) { 537 return 0; 538 } 539 540 /* for instance if previous transfer was terminated due to TX error 541 * it might be that the bus is on it's way to become available 542 * give it at most 3 ms to wake 543 */ 544 err = xiic_bus_busy(i2c); 545 while (err && tries--) { 546 msleep(1); 547 err = xiic_bus_busy(i2c); 548 } 549 550 return err; 551 } 552 553 static void xiic_start_recv(struct xiic_i2c *i2c) 554 { 555 u8 rx_watermark; 556 struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg; 557 unsigned long flags; 558 559 /* Clear and enable Rx full interrupt. */ 560 xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK); 561 562 /* we want to get all but last byte, because the TX_ERROR IRQ is used 563 * to inidicate error ACK on the address, and negative ack on the last 564 * received byte, so to not mix them receive all but last. 565 * In the case where there is only one byte to receive 566 * we can check if ERROR and RX full is set at the same time 567 */ 568 rx_watermark = msg->len; 569 if (rx_watermark > IIC_RX_FIFO_DEPTH) 570 rx_watermark = IIC_RX_FIFO_DEPTH; 571 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rx_watermark - 1); 572 573 local_irq_save(flags); 574 if (!(msg->flags & I2C_M_NOSTART)) 575 /* write the address */ 576 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, 577 i2c_8bit_addr_from_msg(msg) | XIIC_TX_DYN_START_MASK); 578 579 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); 580 581 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, 582 msg->len | ((i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0)); 583 local_irq_restore(flags); 584 585 if (i2c->nmsgs == 1) 586 /* very last, enable bus not busy as well */ 587 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); 588 589 /* the message is tx:ed */ 590 i2c->tx_pos = msg->len; 591 } 592 593 static void xiic_start_send(struct xiic_i2c *i2c) 594 { 595 struct i2c_msg *msg = i2c->tx_msg; 596 597 xiic_irq_clr(i2c, XIIC_INTR_TX_ERROR_MASK); 598 599 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, len: %d", 600 __func__, msg, msg->len); 601 dev_dbg(i2c->adap.dev.parent, "%s entry, ISR: 0x%x, CR: 0x%x\n", 602 __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), 603 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); 604 605 if (!(msg->flags & I2C_M_NOSTART)) { 606 /* write the address */ 607 u16 data = i2c_8bit_addr_from_msg(msg) | 608 XIIC_TX_DYN_START_MASK; 609 if ((i2c->nmsgs == 1) && msg->len == 0) 610 /* no data and last message -> add STOP */ 611 data |= XIIC_TX_DYN_STOP_MASK; 612 613 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); 614 } 615 616 xiic_fill_tx_fifo(i2c); 617 618 /* Clear any pending Tx empty, Tx Error and then enable them. */ 619 xiic_irq_clr_en(i2c, XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_ERROR_MASK | 620 XIIC_INTR_BNB_MASK); 621 } 622 623 static irqreturn_t xiic_isr(int irq, void *dev_id) 624 { 625 struct xiic_i2c *i2c = dev_id; 626 u32 pend, isr, ier; 627 irqreturn_t ret = IRQ_NONE; 628 /* Do not processes a devices interrupts if the device has no 629 * interrupts pending 630 */ 631 632 dev_dbg(i2c->adap.dev.parent, "%s entry\n", __func__); 633 634 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); 635 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); 636 pend = isr & ier; 637 if (pend) 638 ret = IRQ_WAKE_THREAD; 639 640 return ret; 641 } 642 643 static void __xiic_start_xfer(struct xiic_i2c *i2c) 644 { 645 int first = 1; 646 int fifo_space = xiic_tx_fifo_space(i2c); 647 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, fifos space: %d\n", 648 __func__, i2c->tx_msg, fifo_space); 649 650 if (!i2c->tx_msg) 651 return; 652 653 i2c->rx_pos = 0; 654 i2c->tx_pos = 0; 655 i2c->state = STATE_START; 656 while ((fifo_space >= 2) && (first || (i2c->nmsgs > 1))) { 657 if (!first) { 658 i2c->nmsgs--; 659 i2c->tx_msg++; 660 i2c->tx_pos = 0; 661 } else 662 first = 0; 663 664 if (i2c->tx_msg->flags & I2C_M_RD) { 665 /* we dont date putting several reads in the FIFO */ 666 xiic_start_recv(i2c); 667 return; 668 } else { 669 xiic_start_send(i2c); 670 if (xiic_tx_space(i2c) != 0) { 671 /* the message could not be completely sent */ 672 break; 673 } 674 } 675 676 fifo_space = xiic_tx_fifo_space(i2c); 677 } 678 679 /* there are more messages or the current one could not be completely 680 * put into the FIFO, also enable the half empty interrupt 681 */ 682 if (i2c->nmsgs > 1 || xiic_tx_space(i2c)) 683 xiic_irq_clr_en(i2c, XIIC_INTR_TX_HALF_MASK); 684 685 } 686 687 static int xiic_start_xfer(struct xiic_i2c *i2c) 688 { 689 int ret; 690 mutex_lock(&i2c->lock); 691 692 ret = xiic_reinit(i2c); 693 if (!ret) 694 __xiic_start_xfer(i2c); 695 696 mutex_unlock(&i2c->lock); 697 698 return ret; 699 } 700 701 static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 702 { 703 struct xiic_i2c *i2c = i2c_get_adapdata(adap); 704 int err; 705 706 dev_dbg(adap->dev.parent, "%s entry SR: 0x%x\n", __func__, 707 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET)); 708 709 err = pm_runtime_get_sync(i2c->dev); 710 if (err < 0) 711 return err; 712 713 err = xiic_busy(i2c); 714 if (err) 715 goto out; 716 717 i2c->tx_msg = msgs; 718 i2c->nmsgs = num; 719 720 err = xiic_start_xfer(i2c); 721 if (err < 0) { 722 dev_err(adap->dev.parent, "Error xiic_start_xfer\n"); 723 goto out; 724 } 725 726 if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) || 727 (i2c->state == STATE_DONE), HZ)) { 728 err = (i2c->state == STATE_DONE) ? num : -EIO; 729 goto out; 730 } else { 731 i2c->tx_msg = NULL; 732 i2c->rx_msg = NULL; 733 i2c->nmsgs = 0; 734 err = -ETIMEDOUT; 735 goto out; 736 } 737 out: 738 pm_runtime_mark_last_busy(i2c->dev); 739 pm_runtime_put_autosuspend(i2c->dev); 740 return err; 741 } 742 743 static u32 xiic_func(struct i2c_adapter *adap) 744 { 745 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; 746 } 747 748 static const struct i2c_algorithm xiic_algorithm = { 749 .master_xfer = xiic_xfer, 750 .functionality = xiic_func, 751 }; 752 753 static const struct i2c_adapter_quirks xiic_quirks = { 754 .max_read_len = 255, 755 }; 756 757 static const struct i2c_adapter xiic_adapter = { 758 .owner = THIS_MODULE, 759 .name = DRIVER_NAME, 760 .class = I2C_CLASS_DEPRECATED, 761 .algo = &xiic_algorithm, 762 .quirks = &xiic_quirks, 763 }; 764 765 766 static int xiic_i2c_probe(struct platform_device *pdev) 767 { 768 struct xiic_i2c *i2c; 769 struct xiic_i2c_platform_data *pdata; 770 struct resource *res; 771 int ret, irq; 772 u8 i; 773 u32 sr; 774 775 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); 776 if (!i2c) 777 return -ENOMEM; 778 779 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 780 i2c->base = devm_ioremap_resource(&pdev->dev, res); 781 if (IS_ERR(i2c->base)) 782 return PTR_ERR(i2c->base); 783 784 irq = platform_get_irq(pdev, 0); 785 if (irq < 0) 786 return irq; 787 788 pdata = dev_get_platdata(&pdev->dev); 789 790 /* hook up driver to tree */ 791 platform_set_drvdata(pdev, i2c); 792 i2c->adap = xiic_adapter; 793 i2c_set_adapdata(&i2c->adap, i2c); 794 i2c->adap.dev.parent = &pdev->dev; 795 i2c->adap.dev.of_node = pdev->dev.of_node; 796 797 mutex_init(&i2c->lock); 798 init_waitqueue_head(&i2c->wait); 799 800 i2c->clk = devm_clk_get(&pdev->dev, NULL); 801 if (IS_ERR(i2c->clk)) { 802 if (PTR_ERR(i2c->clk) != -EPROBE_DEFER) 803 dev_err(&pdev->dev, "input clock not found.\n"); 804 return PTR_ERR(i2c->clk); 805 } 806 ret = clk_prepare_enable(i2c->clk); 807 if (ret) { 808 dev_err(&pdev->dev, "Unable to enable clock.\n"); 809 return ret; 810 } 811 i2c->dev = &pdev->dev; 812 pm_runtime_set_autosuspend_delay(i2c->dev, XIIC_PM_TIMEOUT); 813 pm_runtime_use_autosuspend(i2c->dev); 814 pm_runtime_set_active(i2c->dev); 815 pm_runtime_enable(i2c->dev); 816 ret = devm_request_threaded_irq(&pdev->dev, irq, xiic_isr, 817 xiic_process, IRQF_ONESHOT, 818 pdev->name, i2c); 819 820 if (ret < 0) { 821 dev_err(&pdev->dev, "Cannot claim IRQ\n"); 822 goto err_clk_dis; 823 } 824 825 i2c->singlemaster = 826 of_property_read_bool(pdev->dev.of_node, "single-master"); 827 828 /* 829 * Detect endianness 830 * Try to reset the TX FIFO. Then check the EMPTY flag. If it is not 831 * set, assume that the endianness was wrong and swap. 832 */ 833 i2c->endianness = LITTLE; 834 xiic_setreg32(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK); 835 /* Reset is cleared in xiic_reinit */ 836 sr = xiic_getreg32(i2c, XIIC_SR_REG_OFFSET); 837 if (!(sr & XIIC_SR_TX_FIFO_EMPTY_MASK)) 838 i2c->endianness = BIG; 839 840 ret = xiic_reinit(i2c); 841 if (ret < 0) { 842 dev_err(&pdev->dev, "Cannot xiic_reinit\n"); 843 goto err_clk_dis; 844 } 845 846 /* add i2c adapter to i2c tree */ 847 ret = i2c_add_adapter(&i2c->adap); 848 if (ret) { 849 xiic_deinit(i2c); 850 goto err_clk_dis; 851 } 852 853 if (pdata) { 854 /* add in known devices to the bus */ 855 for (i = 0; i < pdata->num_devices; i++) 856 i2c_new_client_device(&i2c->adap, pdata->devices + i); 857 } 858 859 return 0; 860 861 err_clk_dis: 862 pm_runtime_set_suspended(&pdev->dev); 863 pm_runtime_disable(&pdev->dev); 864 clk_disable_unprepare(i2c->clk); 865 return ret; 866 } 867 868 static int xiic_i2c_remove(struct platform_device *pdev) 869 { 870 struct xiic_i2c *i2c = platform_get_drvdata(pdev); 871 int ret; 872 873 /* remove adapter & data */ 874 i2c_del_adapter(&i2c->adap); 875 876 ret = pm_runtime_get_sync(i2c->dev); 877 if (ret < 0) 878 return ret; 879 880 xiic_deinit(i2c); 881 pm_runtime_put_sync(i2c->dev); 882 clk_disable_unprepare(i2c->clk); 883 pm_runtime_disable(&pdev->dev); 884 pm_runtime_set_suspended(&pdev->dev); 885 pm_runtime_dont_use_autosuspend(&pdev->dev); 886 887 return 0; 888 } 889 890 #if defined(CONFIG_OF) 891 static const struct of_device_id xiic_of_match[] = { 892 { .compatible = "xlnx,xps-iic-2.00.a", }, 893 {}, 894 }; 895 MODULE_DEVICE_TABLE(of, xiic_of_match); 896 #endif 897 898 static int __maybe_unused xiic_i2c_runtime_suspend(struct device *dev) 899 { 900 struct xiic_i2c *i2c = dev_get_drvdata(dev); 901 902 clk_disable(i2c->clk); 903 904 return 0; 905 } 906 907 static int __maybe_unused xiic_i2c_runtime_resume(struct device *dev) 908 { 909 struct xiic_i2c *i2c = dev_get_drvdata(dev); 910 int ret; 911 912 ret = clk_enable(i2c->clk); 913 if (ret) { 914 dev_err(dev, "Cannot enable clock.\n"); 915 return ret; 916 } 917 918 return 0; 919 } 920 921 static const struct dev_pm_ops xiic_dev_pm_ops = { 922 SET_RUNTIME_PM_OPS(xiic_i2c_runtime_suspend, 923 xiic_i2c_runtime_resume, NULL) 924 }; 925 static struct platform_driver xiic_i2c_driver = { 926 .probe = xiic_i2c_probe, 927 .remove = xiic_i2c_remove, 928 .driver = { 929 .name = DRIVER_NAME, 930 .of_match_table = of_match_ptr(xiic_of_match), 931 .pm = &xiic_dev_pm_ops, 932 }, 933 }; 934 935 module_platform_driver(xiic_i2c_driver); 936 937 MODULE_AUTHOR("info@mocean-labs.com"); 938 MODULE_DESCRIPTION("Xilinx I2C bus driver"); 939 MODULE_LICENSE("GPL v2"); 940 MODULE_ALIAS("platform:"DRIVER_NAME); 941