1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * I2C bus driver for the Cadence I2C controller. 4 * 5 * Copyright (C) 2009 - 2014 Xilinx, Inc. 6 */ 7 8 #include <linux/clk.h> 9 #include <linux/delay.h> 10 #include <linux/i2c.h> 11 #include <linux/interrupt.h> 12 #include <linux/io.h> 13 #include <linux/iopoll.h> 14 #include <linux/module.h> 15 #include <linux/platform_device.h> 16 #include <linux/of.h> 17 #include <linux/pm_runtime.h> 18 #include <linux/pinctrl/consumer.h> 19 #include <linux/reset.h> 20 21 /* Register offsets for the I2C device. */ 22 #define CDNS_I2C_CR_OFFSET 0x00 /* Control Register, RW */ 23 #define CDNS_I2C_SR_OFFSET 0x04 /* Status Register, RO */ 24 #define CDNS_I2C_ADDR_OFFSET 0x08 /* I2C Address Register, RW */ 25 #define CDNS_I2C_DATA_OFFSET 0x0C /* I2C Data Register, RW */ 26 #define CDNS_I2C_ISR_OFFSET 0x10 /* IRQ Status Register, RW */ 27 #define CDNS_I2C_XFER_SIZE_OFFSET 0x14 /* Transfer Size Register, RW */ 28 #define CDNS_I2C_TIME_OUT_OFFSET 0x1C /* Time Out Register, RW */ 29 #define CDNS_I2C_IMR_OFFSET 0x20 /* IRQ Mask Register, RO */ 30 #define CDNS_I2C_IER_OFFSET 0x24 /* IRQ Enable Register, WO */ 31 #define CDNS_I2C_IDR_OFFSET 0x28 /* IRQ Disable Register, WO */ 32 33 /* Control Register Bit mask definitions */ 34 #define CDNS_I2C_CR_HOLD BIT(4) /* Hold Bus bit */ 35 #define CDNS_I2C_CR_ACK_EN BIT(3) 36 #define CDNS_I2C_CR_NEA BIT(2) 37 #define CDNS_I2C_CR_MS BIT(1) 38 /* Read or Write Master transfer 0 = Transmitter, 1 = Receiver */ 39 #define CDNS_I2C_CR_RW BIT(0) 40 /* 1 = Auto init FIFO to zeroes */ 41 #define CDNS_I2C_CR_CLR_FIFO BIT(6) 42 #define CDNS_I2C_CR_DIVA_SHIFT 14 43 #define CDNS_I2C_CR_DIVA_MASK (3 << CDNS_I2C_CR_DIVA_SHIFT) 44 #define CDNS_I2C_CR_DIVB_SHIFT 8 45 #define CDNS_I2C_CR_DIVB_MASK (0x3f << CDNS_I2C_CR_DIVB_SHIFT) 46 47 #define CDNS_I2C_CR_MASTER_EN_MASK (CDNS_I2C_CR_NEA | \ 48 CDNS_I2C_CR_ACK_EN | \ 49 CDNS_I2C_CR_MS) 50 51 #define CDNS_I2C_CR_SLAVE_EN_MASK ~CDNS_I2C_CR_MASTER_EN_MASK 52 53 /* Status Register Bit mask definitions */ 54 #define CDNS_I2C_SR_BA BIT(8) 55 #define CDNS_I2C_SR_TXDV BIT(6) 56 #define CDNS_I2C_SR_RXDV BIT(5) 57 #define CDNS_I2C_SR_RXRW BIT(3) 58 59 /* 60 * I2C Address Register Bit mask definitions 61 * Normal addressing mode uses [6:0] bits. Extended addressing mode uses [9:0] 62 * bits. A write access to this register always initiates a transfer if the I2C 63 * is in master mode. 64 */ 65 #define CDNS_I2C_ADDR_MASK 0x000003FF /* I2C Address Mask */ 66 67 /* 68 * I2C Interrupt Registers Bit mask definitions 69 * All the four interrupt registers (Status/Mask/Enable/Disable) have the same 70 * bit definitions. 71 */ 72 #define CDNS_I2C_IXR_ARB_LOST BIT(9) 73 #define CDNS_I2C_IXR_RX_UNF BIT(7) 74 #define CDNS_I2C_IXR_TX_OVF BIT(6) 75 #define CDNS_I2C_IXR_RX_OVF BIT(5) 76 #define CDNS_I2C_IXR_SLV_RDY BIT(4) 77 #define CDNS_I2C_IXR_TO BIT(3) 78 #define CDNS_I2C_IXR_NACK BIT(2) 79 #define CDNS_I2C_IXR_DATA BIT(1) 80 #define CDNS_I2C_IXR_COMP BIT(0) 81 82 #define CDNS_I2C_IXR_ALL_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \ 83 CDNS_I2C_IXR_RX_UNF | \ 84 CDNS_I2C_IXR_TX_OVF | \ 85 CDNS_I2C_IXR_RX_OVF | \ 86 CDNS_I2C_IXR_SLV_RDY | \ 87 CDNS_I2C_IXR_TO | \ 88 CDNS_I2C_IXR_NACK | \ 89 CDNS_I2C_IXR_DATA | \ 90 CDNS_I2C_IXR_COMP) 91 92 #define CDNS_I2C_IXR_ERR_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \ 93 CDNS_I2C_IXR_RX_UNF | \ 94 CDNS_I2C_IXR_TX_OVF | \ 95 CDNS_I2C_IXR_RX_OVF | \ 96 CDNS_I2C_IXR_NACK) 97 98 #define CDNS_I2C_ENABLED_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \ 99 CDNS_I2C_IXR_RX_UNF | \ 100 CDNS_I2C_IXR_TX_OVF | \ 101 CDNS_I2C_IXR_RX_OVF | \ 102 CDNS_I2C_IXR_NACK | \ 103 CDNS_I2C_IXR_DATA | \ 104 CDNS_I2C_IXR_COMP) 105 106 #define CDNS_I2C_IXR_SLAVE_INTR_MASK (CDNS_I2C_IXR_RX_UNF | \ 107 CDNS_I2C_IXR_TX_OVF | \ 108 CDNS_I2C_IXR_RX_OVF | \ 109 CDNS_I2C_IXR_TO | \ 110 CDNS_I2C_IXR_NACK | \ 111 CDNS_I2C_IXR_DATA | \ 112 CDNS_I2C_IXR_COMP) 113 114 #define CDNS_I2C_TIMEOUT msecs_to_jiffies(1000) 115 /* timeout for pm runtime autosuspend */ 116 #define CNDS_I2C_PM_TIMEOUT 1000 /* ms */ 117 118 #define CDNS_I2C_FIFO_DEPTH_DEFAULT 16 119 #define CDNS_I2C_MAX_TRANSFER_SIZE 255 120 /* Transfer size in multiples of data interrupt depth */ 121 #define CDNS_I2C_TRANSFER_SIZE(max) ((max) - 3) 122 123 #define DRIVER_NAME "cdns-i2c" 124 125 #define CDNS_I2C_DIVA_MAX 4 126 #define CDNS_I2C_DIVB_MAX 64 127 128 #define CDNS_I2C_TIMEOUT_MAX 0xFF 129 130 #define CDNS_I2C_BROKEN_HOLD_BIT BIT(0) 131 #define CDNS_I2C_POLL_US 100000 132 #define CDNS_I2C_TIMEOUT_US 500000 133 134 #define cdns_i2c_readreg(offset) readl_relaxed(id->membase + offset) 135 #define cdns_i2c_writereg(val, offset) writel_relaxed(val, id->membase + offset) 136 137 #if IS_ENABLED(CONFIG_I2C_SLAVE) 138 /** 139 * enum cdns_i2c_mode - I2C Controller current operating mode 140 * 141 * @CDNS_I2C_MODE_SLAVE: I2C controller operating in slave mode 142 * @CDNS_I2C_MODE_MASTER: I2C Controller operating in master mode 143 */ 144 enum cdns_i2c_mode { 145 CDNS_I2C_MODE_SLAVE, 146 CDNS_I2C_MODE_MASTER, 147 }; 148 149 /** 150 * enum cdns_i2c_slave_state - Slave state when I2C is operating in slave mode 151 * 152 * @CDNS_I2C_SLAVE_STATE_IDLE: I2C slave idle 153 * @CDNS_I2C_SLAVE_STATE_SEND: I2C slave sending data to master 154 * @CDNS_I2C_SLAVE_STATE_RECV: I2C slave receiving data from master 155 */ 156 enum cdns_i2c_slave_state { 157 CDNS_I2C_SLAVE_STATE_IDLE, 158 CDNS_I2C_SLAVE_STATE_SEND, 159 CDNS_I2C_SLAVE_STATE_RECV, 160 }; 161 #endif 162 163 /** 164 * struct cdns_i2c - I2C device private data structure 165 * 166 * @dev: Pointer to device structure 167 * @membase: Base address of the I2C device 168 * @adap: I2C adapter instance 169 * @p_msg: Message pointer 170 * @err_status: Error status in Interrupt Status Register 171 * @xfer_done: Transfer complete status 172 * @p_send_buf: Pointer to transmit buffer 173 * @p_recv_buf: Pointer to receive buffer 174 * @send_count: Number of bytes still expected to send 175 * @recv_count: Number of bytes still expected to receive 176 * @curr_recv_count: Number of bytes to be received in current transfer 177 * @input_clk: Input clock to I2C controller 178 * @i2c_clk: Maximum I2C clock speed 179 * @bus_hold_flag: Flag used in repeated start for clearing HOLD bit 180 * @clk: Pointer to struct clk 181 * @clk_rate_change_nb: Notifier block for clock rate changes 182 * @reset: Reset control for the device 183 * @quirks: flag for broken hold bit usage in r1p10 184 * @ctrl_reg: Cached value of the control register. 185 * @ctrl_reg_diva_divb: value of fields DIV_A and DIV_B from CR register 186 * @slave: Registered slave instance. 187 * @dev_mode: I2C operating role(master/slave). 188 * @slave_state: I2C Slave state(idle/read/write). 189 * @fifo_depth: The depth of the transfer FIFO 190 * @transfer_size: The maximum number of bytes in one transfer 191 */ 192 struct cdns_i2c { 193 struct device *dev; 194 void __iomem *membase; 195 struct i2c_adapter adap; 196 struct i2c_msg *p_msg; 197 int err_status; 198 struct completion xfer_done; 199 unsigned char *p_send_buf; 200 unsigned char *p_recv_buf; 201 unsigned int send_count; 202 unsigned int recv_count; 203 unsigned int curr_recv_count; 204 unsigned long input_clk; 205 unsigned int i2c_clk; 206 unsigned int bus_hold_flag; 207 struct clk *clk; 208 struct notifier_block clk_rate_change_nb; 209 struct reset_control *reset; 210 u32 quirks; 211 u32 ctrl_reg; 212 struct i2c_bus_recovery_info rinfo; 213 #if IS_ENABLED(CONFIG_I2C_SLAVE) 214 u16 ctrl_reg_diva_divb; 215 struct i2c_client *slave; 216 enum cdns_i2c_mode dev_mode; 217 enum cdns_i2c_slave_state slave_state; 218 #endif 219 u32 fifo_depth; 220 unsigned int transfer_size; 221 }; 222 223 struct cdns_platform_data { 224 u32 quirks; 225 }; 226 227 #define to_cdns_i2c(_nb) container_of(_nb, struct cdns_i2c, \ 228 clk_rate_change_nb) 229 230 /** 231 * cdns_i2c_clear_bus_hold - Clear bus hold bit 232 * @id: Pointer to driver data struct 233 * 234 * Helper to clear the controller's bus hold bit. 235 */ 236 static void cdns_i2c_clear_bus_hold(struct cdns_i2c *id) 237 { 238 u32 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 239 if (reg & CDNS_I2C_CR_HOLD) 240 cdns_i2c_writereg(reg & ~CDNS_I2C_CR_HOLD, CDNS_I2C_CR_OFFSET); 241 } 242 243 static inline bool cdns_is_holdquirk(struct cdns_i2c *id, bool hold_wrkaround) 244 { 245 return (hold_wrkaround && 246 (id->curr_recv_count == id->fifo_depth + 1)); 247 } 248 249 #if IS_ENABLED(CONFIG_I2C_SLAVE) 250 static void cdns_i2c_set_mode(enum cdns_i2c_mode mode, struct cdns_i2c *id) 251 { 252 /* Disable all interrupts */ 253 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET); 254 255 /* Clear FIFO and transfer size */ 256 cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET); 257 258 /* Update device mode and state */ 259 id->dev_mode = mode; 260 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 261 262 switch (mode) { 263 case CDNS_I2C_MODE_MASTER: 264 /* Enable i2c master */ 265 cdns_i2c_writereg(id->ctrl_reg_diva_divb | 266 CDNS_I2C_CR_MASTER_EN_MASK, 267 CDNS_I2C_CR_OFFSET); 268 /* 269 * This delay is needed to give the IP some time to switch to 270 * the master mode. With lower values(like 110 us) i2cdetect 271 * will not detect any slave and without this delay, the IP will 272 * trigger a timeout interrupt. 273 */ 274 usleep_range(115, 125); 275 break; 276 case CDNS_I2C_MODE_SLAVE: 277 /* Enable i2c slave */ 278 cdns_i2c_writereg(id->ctrl_reg_diva_divb & 279 CDNS_I2C_CR_SLAVE_EN_MASK, 280 CDNS_I2C_CR_OFFSET); 281 282 /* Setting slave address */ 283 cdns_i2c_writereg(id->slave->addr & CDNS_I2C_ADDR_MASK, 284 CDNS_I2C_ADDR_OFFSET); 285 286 /* Enable slave send/receive interrupts */ 287 cdns_i2c_writereg(CDNS_I2C_IXR_SLAVE_INTR_MASK, 288 CDNS_I2C_IER_OFFSET); 289 break; 290 } 291 } 292 293 static void cdns_i2c_slave_rcv_data(struct cdns_i2c *id) 294 { 295 u8 bytes; 296 unsigned char data; 297 298 /* Prepare backend for data reception */ 299 if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) { 300 id->slave_state = CDNS_I2C_SLAVE_STATE_RECV; 301 i2c_slave_event(id->slave, I2C_SLAVE_WRITE_REQUESTED, NULL); 302 } 303 304 /* Fetch number of bytes to receive */ 305 bytes = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); 306 307 /* Read data and send to backend */ 308 while (bytes--) { 309 data = cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET); 310 i2c_slave_event(id->slave, I2C_SLAVE_WRITE_RECEIVED, &data); 311 } 312 } 313 314 static void cdns_i2c_slave_send_data(struct cdns_i2c *id) 315 { 316 u8 data; 317 318 /* Prepare backend for data transmission */ 319 if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) { 320 id->slave_state = CDNS_I2C_SLAVE_STATE_SEND; 321 i2c_slave_event(id->slave, I2C_SLAVE_READ_REQUESTED, &data); 322 } else { 323 i2c_slave_event(id->slave, I2C_SLAVE_READ_PROCESSED, &data); 324 } 325 326 /* Send data over bus */ 327 cdns_i2c_writereg(data, CDNS_I2C_DATA_OFFSET); 328 } 329 330 /** 331 * cdns_i2c_slave_isr - Interrupt handler for the I2C device in slave role 332 * @ptr: Pointer to I2C device private data 333 * 334 * This function handles the data interrupt and transfer complete interrupt of 335 * the I2C device in slave role. 336 * 337 * Return: IRQ_HANDLED always 338 */ 339 static irqreturn_t cdns_i2c_slave_isr(void *ptr) 340 { 341 struct cdns_i2c *id = ptr; 342 unsigned int isr_status, i2c_status; 343 344 /* Fetch the interrupt status */ 345 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 346 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); 347 348 /* Ignore masked interrupts */ 349 isr_status &= ~cdns_i2c_readreg(CDNS_I2C_IMR_OFFSET); 350 351 /* Fetch transfer mode (send/receive) */ 352 i2c_status = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET); 353 354 /* Handle data send/receive */ 355 if (i2c_status & CDNS_I2C_SR_RXRW) { 356 /* Send data to master */ 357 if (isr_status & CDNS_I2C_IXR_DATA) 358 cdns_i2c_slave_send_data(id); 359 360 if (isr_status & CDNS_I2C_IXR_COMP) { 361 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 362 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL); 363 } 364 } else { 365 /* Receive data from master */ 366 if (isr_status & CDNS_I2C_IXR_DATA) 367 cdns_i2c_slave_rcv_data(id); 368 369 if (isr_status & CDNS_I2C_IXR_COMP) { 370 cdns_i2c_slave_rcv_data(id); 371 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 372 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL); 373 } 374 } 375 376 /* Master indicated xfer stop or fifo underflow/overflow */ 377 if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_RX_OVF | 378 CDNS_I2C_IXR_RX_UNF | CDNS_I2C_IXR_TX_OVF)) { 379 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 380 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL); 381 cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET); 382 } 383 384 return IRQ_HANDLED; 385 } 386 #endif 387 388 /** 389 * cdns_i2c_master_isr - Interrupt handler for the I2C device in master role 390 * @ptr: Pointer to I2C device private data 391 * 392 * This function handles the data interrupt, transfer complete interrupt and 393 * the error interrupts of the I2C device in master role. 394 * 395 * Return: IRQ_HANDLED always 396 */ 397 static irqreturn_t cdns_i2c_master_isr(void *ptr) 398 { 399 unsigned int isr_status, avail_bytes; 400 unsigned int bytes_to_send; 401 bool updatetx; 402 struct cdns_i2c *id = ptr; 403 /* Signal completion only after everything is updated */ 404 int done_flag = 0; 405 irqreturn_t status = IRQ_NONE; 406 407 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 408 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); 409 id->err_status = 0; 410 411 /* Handling nack and arbitration lost interrupt */ 412 if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_ARB_LOST)) { 413 done_flag = 1; 414 status = IRQ_HANDLED; 415 } 416 417 /* 418 * Check if transfer size register needs to be updated again for a 419 * large data receive operation. 420 */ 421 updatetx = id->recv_count > id->curr_recv_count; 422 423 /* When receiving, handle data interrupt and completion interrupt */ 424 if (id->p_recv_buf && 425 ((isr_status & CDNS_I2C_IXR_COMP) || 426 (isr_status & CDNS_I2C_IXR_DATA))) { 427 /* Read data if receive data valid is set */ 428 while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & 429 CDNS_I2C_SR_RXDV) { 430 if (id->recv_count > 0) { 431 *(id->p_recv_buf)++ = 432 cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET); 433 id->recv_count--; 434 id->curr_recv_count--; 435 436 /* 437 * Clear hold bit that was set for FIFO control 438 * if RX data left is less than or equal to 439 * FIFO DEPTH unless repeated start is selected 440 */ 441 if (id->recv_count <= id->fifo_depth && 442 !id->bus_hold_flag) 443 cdns_i2c_clear_bus_hold(id); 444 445 } else { 446 dev_err(id->adap.dev.parent, 447 "xfer_size reg rollover. xfer aborted!\n"); 448 id->err_status |= CDNS_I2C_IXR_TO; 449 break; 450 } 451 452 if (cdns_is_holdquirk(id, updatetx)) 453 break; 454 } 455 456 /* 457 * The controller sends NACK to the slave when transfer size 458 * register reaches zero without considering the HOLD bit. 459 * This workaround is implemented for large data transfers to 460 * maintain transfer size non-zero while performing a large 461 * receive operation. 462 */ 463 if (cdns_is_holdquirk(id, updatetx)) { 464 /* wait while fifo is full */ 465 while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) != 466 (id->curr_recv_count - id->fifo_depth)) 467 ; 468 469 /* 470 * Check number of bytes to be received against maximum 471 * transfer size and update register accordingly. 472 */ 473 if (((int)(id->recv_count) - id->fifo_depth) > 474 id->transfer_size) { 475 cdns_i2c_writereg(id->transfer_size, 476 CDNS_I2C_XFER_SIZE_OFFSET); 477 id->curr_recv_count = id->transfer_size + 478 id->fifo_depth; 479 } else { 480 cdns_i2c_writereg(id->recv_count - 481 id->fifo_depth, 482 CDNS_I2C_XFER_SIZE_OFFSET); 483 id->curr_recv_count = id->recv_count; 484 } 485 } 486 487 /* Clear hold (if not repeated start) and signal completion */ 488 if ((isr_status & CDNS_I2C_IXR_COMP) && !id->recv_count) { 489 if (!id->bus_hold_flag) 490 cdns_i2c_clear_bus_hold(id); 491 done_flag = 1; 492 } 493 494 status = IRQ_HANDLED; 495 } 496 497 /* When sending, handle transfer complete interrupt */ 498 if ((isr_status & CDNS_I2C_IXR_COMP) && !id->p_recv_buf) { 499 /* 500 * If there is more data to be sent, calculate the 501 * space available in FIFO and fill with that many bytes. 502 */ 503 if (id->send_count) { 504 avail_bytes = id->fifo_depth - 505 cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); 506 if (id->send_count > avail_bytes) 507 bytes_to_send = avail_bytes; 508 else 509 bytes_to_send = id->send_count; 510 511 while (bytes_to_send--) { 512 cdns_i2c_writereg( 513 (*(id->p_send_buf)++), 514 CDNS_I2C_DATA_OFFSET); 515 id->send_count--; 516 } 517 } else { 518 /* 519 * Signal the completion of transaction and 520 * clear the hold bus bit if there are no 521 * further messages to be processed. 522 */ 523 done_flag = 1; 524 } 525 if (!id->send_count && !id->bus_hold_flag) 526 cdns_i2c_clear_bus_hold(id); 527 528 status = IRQ_HANDLED; 529 } 530 531 /* Update the status for errors */ 532 id->err_status |= isr_status & CDNS_I2C_IXR_ERR_INTR_MASK; 533 if (id->err_status) 534 status = IRQ_HANDLED; 535 536 if (done_flag) 537 complete(&id->xfer_done); 538 539 return status; 540 } 541 542 /** 543 * cdns_i2c_isr - Interrupt handler for the I2C device 544 * @irq: irq number for the I2C device 545 * @ptr: void pointer to cdns_i2c structure 546 * 547 * This function passes the control to slave/master based on current role of 548 * i2c controller. 549 * 550 * Return: IRQ_HANDLED always 551 */ 552 static irqreturn_t cdns_i2c_isr(int irq, void *ptr) 553 { 554 #if IS_ENABLED(CONFIG_I2C_SLAVE) 555 struct cdns_i2c *id = ptr; 556 557 if (id->dev_mode == CDNS_I2C_MODE_SLAVE) 558 return cdns_i2c_slave_isr(ptr); 559 #endif 560 return cdns_i2c_master_isr(ptr); 561 } 562 563 /** 564 * cdns_i2c_mrecv - Prepare and start a master receive operation 565 * @id: pointer to the i2c device structure 566 */ 567 static void cdns_i2c_mrecv(struct cdns_i2c *id) 568 { 569 unsigned int ctrl_reg; 570 unsigned int isr_status; 571 unsigned long flags; 572 bool hold_clear = false; 573 bool irq_save = false; 574 575 u32 addr; 576 577 id->p_recv_buf = id->p_msg->buf; 578 id->recv_count = id->p_msg->len; 579 580 /* Put the controller in master receive mode and clear the FIFO */ 581 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 582 ctrl_reg |= CDNS_I2C_CR_RW | CDNS_I2C_CR_CLR_FIFO; 583 584 /* 585 * Receive up to I2C_SMBUS_BLOCK_MAX data bytes, plus one message length 586 * byte, plus one checksum byte if PEC is enabled. p_msg->len will be 2 if 587 * PEC is enabled, otherwise 1. 588 */ 589 if (id->p_msg->flags & I2C_M_RECV_LEN) 590 id->recv_count = I2C_SMBUS_BLOCK_MAX + id->p_msg->len; 591 592 id->curr_recv_count = id->recv_count; 593 594 /* 595 * Check for the message size against FIFO depth and set the 596 * 'hold bus' bit if it is greater than FIFO depth. 597 */ 598 if (id->recv_count > id->fifo_depth) 599 ctrl_reg |= CDNS_I2C_CR_HOLD; 600 601 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); 602 603 /* Clear the interrupts in interrupt status register */ 604 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 605 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); 606 607 /* 608 * The no. of bytes to receive is checked against the limit of 609 * max transfer size. Set transfer size register with no of bytes 610 * receive if it is less than transfer size and transfer size if 611 * it is more. Enable the interrupts. 612 */ 613 if (id->recv_count > id->transfer_size) { 614 cdns_i2c_writereg(id->transfer_size, 615 CDNS_I2C_XFER_SIZE_OFFSET); 616 id->curr_recv_count = id->transfer_size; 617 } else { 618 cdns_i2c_writereg(id->recv_count, CDNS_I2C_XFER_SIZE_OFFSET); 619 } 620 621 /* Determine hold_clear based on number of bytes to receive and hold flag */ 622 if (!id->bus_hold_flag && id->recv_count <= id->fifo_depth) { 623 if (ctrl_reg & CDNS_I2C_CR_HOLD) { 624 hold_clear = true; 625 if (id->quirks & CDNS_I2C_BROKEN_HOLD_BIT) 626 irq_save = true; 627 } 628 } 629 630 addr = id->p_msg->addr; 631 addr &= CDNS_I2C_ADDR_MASK; 632 633 if (hold_clear) { 634 ctrl_reg &= ~CDNS_I2C_CR_HOLD; 635 /* 636 * In case of Xilinx Zynq SOC, clear the HOLD bit before transfer size 637 * register reaches '0'. This is an IP bug which causes transfer size 638 * register overflow to 0xFF. To satisfy this timing requirement, 639 * disable the interrupts on current processor core between register 640 * writes to slave address register and control register. 641 */ 642 if (irq_save) 643 local_irq_save(flags); 644 645 cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET); 646 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); 647 /* Read it back to avoid bufferring and make sure write happens */ 648 cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 649 650 if (irq_save) 651 local_irq_restore(flags); 652 } else { 653 cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET); 654 } 655 656 cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); 657 } 658 659 /** 660 * cdns_i2c_msend - Prepare and start a master send operation 661 * @id: pointer to the i2c device 662 */ 663 static void cdns_i2c_msend(struct cdns_i2c *id) 664 { 665 unsigned int avail_bytes; 666 unsigned int bytes_to_send; 667 unsigned int ctrl_reg; 668 unsigned int isr_status; 669 670 id->p_recv_buf = NULL; 671 id->p_send_buf = id->p_msg->buf; 672 id->send_count = id->p_msg->len; 673 674 /* Set the controller in Master transmit mode and clear the FIFO. */ 675 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 676 ctrl_reg &= ~CDNS_I2C_CR_RW; 677 ctrl_reg |= CDNS_I2C_CR_CLR_FIFO; 678 679 /* 680 * Check for the message size against FIFO depth and set the 681 * 'hold bus' bit if it is greater than FIFO depth. 682 */ 683 if (id->send_count > id->fifo_depth) 684 ctrl_reg |= CDNS_I2C_CR_HOLD; 685 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); 686 687 /* Clear the interrupts in interrupt status register. */ 688 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 689 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); 690 691 /* 692 * Calculate the space available in FIFO. Check the message length 693 * against the space available, and fill the FIFO accordingly. 694 * Enable the interrupts. 695 */ 696 avail_bytes = id->fifo_depth - 697 cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); 698 699 if (id->send_count > avail_bytes) 700 bytes_to_send = avail_bytes; 701 else 702 bytes_to_send = id->send_count; 703 704 while (bytes_to_send--) { 705 cdns_i2c_writereg((*(id->p_send_buf)++), CDNS_I2C_DATA_OFFSET); 706 id->send_count--; 707 } 708 709 /* 710 * Clear the bus hold flag if there is no more data 711 * and if it is the last message. 712 */ 713 if (!id->bus_hold_flag && !id->send_count) 714 cdns_i2c_clear_bus_hold(id); 715 /* Set the slave address in address register - triggers operation. */ 716 cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK, 717 CDNS_I2C_ADDR_OFFSET); 718 719 cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); 720 } 721 722 /** 723 * cdns_i2c_master_reset - Reset the interface 724 * @adap: pointer to the i2c adapter driver instance 725 * 726 * This function cleanup the fifos, clear the hold bit and status 727 * and disable the interrupts. 728 */ 729 static void cdns_i2c_master_reset(struct i2c_adapter *adap) 730 { 731 struct cdns_i2c *id = adap->algo_data; 732 u32 regval; 733 734 /* Disable the interrupts */ 735 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET); 736 /* Clear the hold bit and fifos */ 737 regval = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 738 regval &= ~CDNS_I2C_CR_HOLD; 739 regval |= CDNS_I2C_CR_CLR_FIFO; 740 cdns_i2c_writereg(regval, CDNS_I2C_CR_OFFSET); 741 /* Update the transfercount register to zero */ 742 cdns_i2c_writereg(0, CDNS_I2C_XFER_SIZE_OFFSET); 743 /* Clear the interrupt status register */ 744 regval = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 745 cdns_i2c_writereg(regval, CDNS_I2C_ISR_OFFSET); 746 /* Clear the status register */ 747 regval = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET); 748 cdns_i2c_writereg(regval, CDNS_I2C_SR_OFFSET); 749 } 750 751 static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg, 752 struct i2c_adapter *adap) 753 { 754 unsigned long time_left, msg_timeout; 755 u32 reg; 756 757 id->p_msg = msg; 758 id->err_status = 0; 759 reinit_completion(&id->xfer_done); 760 761 /* Check for the TEN Bit mode on each msg */ 762 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 763 if (msg->flags & I2C_M_TEN) { 764 if (reg & CDNS_I2C_CR_NEA) 765 cdns_i2c_writereg(reg & ~CDNS_I2C_CR_NEA, 766 CDNS_I2C_CR_OFFSET); 767 } else { 768 if (!(reg & CDNS_I2C_CR_NEA)) 769 cdns_i2c_writereg(reg | CDNS_I2C_CR_NEA, 770 CDNS_I2C_CR_OFFSET); 771 } 772 773 /* Check for the R/W flag on each msg */ 774 if (msg->flags & I2C_M_RD) 775 cdns_i2c_mrecv(id); 776 else 777 cdns_i2c_msend(id); 778 779 /* Minimal time to execute this message */ 780 msg_timeout = msecs_to_jiffies((1000 * msg->len * BITS_PER_BYTE) / id->i2c_clk); 781 /* Plus some wiggle room */ 782 msg_timeout += msecs_to_jiffies(500); 783 784 if (msg_timeout < adap->timeout) 785 msg_timeout = adap->timeout; 786 787 /* Wait for the signal of completion */ 788 time_left = wait_for_completion_timeout(&id->xfer_done, msg_timeout); 789 if (time_left == 0) { 790 cdns_i2c_master_reset(adap); 791 dev_err(id->adap.dev.parent, 792 "timeout waiting on completion\n"); 793 return -ETIMEDOUT; 794 } 795 796 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, 797 CDNS_I2C_IDR_OFFSET); 798 799 /* If it is bus arbitration error, try again */ 800 if (id->err_status & CDNS_I2C_IXR_ARB_LOST) 801 return -EAGAIN; 802 803 if (msg->flags & I2C_M_RECV_LEN) 804 msg->len += min_t(unsigned int, msg->buf[0], I2C_SMBUS_BLOCK_MAX); 805 806 return 0; 807 } 808 809 /** 810 * cdns_i2c_master_xfer - The main i2c transfer function 811 * @adap: pointer to the i2c adapter driver instance 812 * @msgs: pointer to the i2c message structure 813 * @num: the number of messages to transfer 814 * 815 * Initiates the send/recv activity based on the transfer message received. 816 * 817 * Return: number of msgs processed on success, negative error otherwise 818 */ 819 static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 820 int num) 821 { 822 int ret, count; 823 u32 reg; 824 struct cdns_i2c *id = adap->algo_data; 825 bool hold_quirk; 826 #if IS_ENABLED(CONFIG_I2C_SLAVE) 827 bool change_role = false; 828 #endif 829 830 ret = pm_runtime_resume_and_get(id->dev); 831 if (ret < 0) 832 return ret; 833 834 #if IS_ENABLED(CONFIG_I2C_SLAVE) 835 /* Check i2c operating mode and switch if possible */ 836 if (id->dev_mode == CDNS_I2C_MODE_SLAVE) { 837 if (id->slave_state != CDNS_I2C_SLAVE_STATE_IDLE) { 838 ret = -EAGAIN; 839 goto out; 840 } 841 842 /* Set mode to master */ 843 cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id); 844 845 /* Mark flag to change role once xfer is completed */ 846 change_role = true; 847 } 848 #endif 849 850 /* Check if the bus is free */ 851 852 ret = readl_relaxed_poll_timeout(id->membase + CDNS_I2C_SR_OFFSET, 853 reg, 854 !(reg & CDNS_I2C_SR_BA), 855 CDNS_I2C_POLL_US, CDNS_I2C_TIMEOUT_US); 856 if (ret) { 857 ret = -EAGAIN; 858 if (id->adap.bus_recovery_info) 859 i2c_recover_bus(adap); 860 goto out; 861 } 862 863 hold_quirk = !!(id->quirks & CDNS_I2C_BROKEN_HOLD_BIT); 864 /* 865 * Set the flag to one when multiple messages are to be 866 * processed with a repeated start. 867 */ 868 if (num > 1) { 869 /* 870 * This controller does not give completion interrupt after a 871 * master receive message if HOLD bit is set (repeated start), 872 * resulting in SW timeout. Hence, if a receive message is 873 * followed by any other message, an error is returned 874 * indicating that this sequence is not supported. 875 */ 876 for (count = 0; (count < num - 1 && hold_quirk); count++) { 877 if (msgs[count].flags & I2C_M_RD) { 878 dev_warn(adap->dev.parent, 879 "Can't do repeated start after a receive message\n"); 880 ret = -EOPNOTSUPP; 881 goto out; 882 } 883 } 884 id->bus_hold_flag = 1; 885 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 886 reg |= CDNS_I2C_CR_HOLD; 887 cdns_i2c_writereg(reg, CDNS_I2C_CR_OFFSET); 888 } else { 889 id->bus_hold_flag = 0; 890 } 891 892 /* Process the msg one by one */ 893 for (count = 0; count < num; count++, msgs++) { 894 if (count == (num - 1)) 895 id->bus_hold_flag = 0; 896 897 ret = cdns_i2c_process_msg(id, msgs, adap); 898 if (ret) 899 goto out; 900 901 /* Report the other error interrupts to application */ 902 if (id->err_status) { 903 cdns_i2c_master_reset(adap); 904 905 if (id->err_status & CDNS_I2C_IXR_NACK) { 906 ret = -ENXIO; 907 goto out; 908 } 909 ret = -EIO; 910 goto out; 911 } 912 } 913 914 ret = num; 915 916 out: 917 918 #if IS_ENABLED(CONFIG_I2C_SLAVE) 919 /* Switch i2c mode to slave */ 920 if (change_role) 921 cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id); 922 #endif 923 924 pm_runtime_mark_last_busy(id->dev); 925 pm_runtime_put_autosuspend(id->dev); 926 return ret; 927 } 928 929 /** 930 * cdns_i2c_func - Returns the supported features of the I2C driver 931 * @adap: pointer to the i2c adapter structure 932 * 933 * Return: 32 bit value, each bit corresponding to a feature 934 */ 935 static u32 cdns_i2c_func(struct i2c_adapter *adap) 936 { 937 u32 func = I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | 938 (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) | 939 I2C_FUNC_SMBUS_BLOCK_DATA; 940 941 #if IS_ENABLED(CONFIG_I2C_SLAVE) 942 func |= I2C_FUNC_SLAVE; 943 #endif 944 945 return func; 946 } 947 948 #if IS_ENABLED(CONFIG_I2C_SLAVE) 949 static int cdns_reg_slave(struct i2c_client *slave) 950 { 951 int ret; 952 struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c, 953 adap); 954 955 if (id->slave) 956 return -EBUSY; 957 958 if (slave->flags & I2C_CLIENT_TEN) 959 return -EAFNOSUPPORT; 960 961 ret = pm_runtime_resume_and_get(id->dev); 962 if (ret < 0) 963 return ret; 964 965 /* Store slave information */ 966 id->slave = slave; 967 968 /* Enable I2C slave */ 969 cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id); 970 971 return 0; 972 } 973 974 static int cdns_unreg_slave(struct i2c_client *slave) 975 { 976 struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c, 977 adap); 978 979 pm_runtime_put(id->dev); 980 981 /* Remove slave information */ 982 id->slave = NULL; 983 984 /* Enable I2C master */ 985 cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id); 986 987 return 0; 988 } 989 #endif 990 991 static const struct i2c_algorithm cdns_i2c_algo = { 992 .master_xfer = cdns_i2c_master_xfer, 993 .functionality = cdns_i2c_func, 994 #if IS_ENABLED(CONFIG_I2C_SLAVE) 995 .reg_slave = cdns_reg_slave, 996 .unreg_slave = cdns_unreg_slave, 997 #endif 998 }; 999 1000 /** 1001 * cdns_i2c_calc_divs - Calculate clock dividers 1002 * @f: I2C clock frequency 1003 * @input_clk: Input clock frequency 1004 * @a: First divider (return value) 1005 * @b: Second divider (return value) 1006 * 1007 * f is used as input and output variable. As input it is used as target I2C 1008 * frequency. On function exit f holds the actually resulting I2C frequency. 1009 * 1010 * Return: 0 on success, negative errno otherwise. 1011 */ 1012 static int cdns_i2c_calc_divs(unsigned long *f, unsigned long input_clk, 1013 unsigned int *a, unsigned int *b) 1014 { 1015 unsigned long fscl = *f, best_fscl = *f, actual_fscl, temp; 1016 unsigned int div_a, div_b, calc_div_a = 0, calc_div_b = 0; 1017 unsigned int last_error, current_error; 1018 1019 /* calculate (divisor_a+1) x (divisor_b+1) */ 1020 temp = input_clk / (22 * fscl); 1021 1022 /* 1023 * If the calculated value is negative or 0, the fscl input is out of 1024 * range. Return error. 1025 */ 1026 if (!temp || (temp > (CDNS_I2C_DIVA_MAX * CDNS_I2C_DIVB_MAX))) 1027 return -EINVAL; 1028 1029 last_error = -1; 1030 for (div_a = 0; div_a < CDNS_I2C_DIVA_MAX; div_a++) { 1031 div_b = DIV_ROUND_UP(input_clk, 22 * fscl * (div_a + 1)); 1032 1033 if ((div_b < 1) || (div_b > CDNS_I2C_DIVB_MAX)) 1034 continue; 1035 div_b--; 1036 1037 actual_fscl = input_clk / (22 * (div_a + 1) * (div_b + 1)); 1038 1039 if (actual_fscl > fscl) 1040 continue; 1041 1042 current_error = fscl - actual_fscl; 1043 1044 if (last_error > current_error) { 1045 calc_div_a = div_a; 1046 calc_div_b = div_b; 1047 best_fscl = actual_fscl; 1048 last_error = current_error; 1049 } 1050 } 1051 1052 *a = calc_div_a; 1053 *b = calc_div_b; 1054 *f = best_fscl; 1055 1056 return 0; 1057 } 1058 1059 /** 1060 * cdns_i2c_setclk - This function sets the serial clock rate for the I2C device 1061 * @clk_in: I2C clock input frequency in Hz 1062 * @id: Pointer to the I2C device structure 1063 * 1064 * The device must be idle rather than busy transferring data before setting 1065 * these device options. 1066 * The data rate is set by values in the control register. 1067 * The formula for determining the correct register values is 1068 * Fscl = Fpclk/(22 x (divisor_a+1) x (divisor_b+1)) 1069 * See the hardware data sheet for a full explanation of setting the serial 1070 * clock rate. The clock can not be faster than the input clock divide by 22. 1071 * The two most common clock rates are 100KHz and 400KHz. 1072 * 1073 * Return: 0 on success, negative error otherwise 1074 */ 1075 static int cdns_i2c_setclk(unsigned long clk_in, struct cdns_i2c *id) 1076 { 1077 unsigned int div_a, div_b; 1078 unsigned int ctrl_reg; 1079 int ret = 0; 1080 unsigned long fscl = id->i2c_clk; 1081 1082 ret = cdns_i2c_calc_divs(&fscl, clk_in, &div_a, &div_b); 1083 if (ret) 1084 return ret; 1085 1086 ctrl_reg = id->ctrl_reg; 1087 ctrl_reg &= ~(CDNS_I2C_CR_DIVA_MASK | CDNS_I2C_CR_DIVB_MASK); 1088 ctrl_reg |= ((div_a << CDNS_I2C_CR_DIVA_SHIFT) | 1089 (div_b << CDNS_I2C_CR_DIVB_SHIFT)); 1090 id->ctrl_reg = ctrl_reg; 1091 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); 1092 #if IS_ENABLED(CONFIG_I2C_SLAVE) 1093 id->ctrl_reg_diva_divb = ctrl_reg & (CDNS_I2C_CR_DIVA_MASK | 1094 CDNS_I2C_CR_DIVB_MASK); 1095 #endif 1096 return 0; 1097 } 1098 1099 /** 1100 * cdns_i2c_clk_notifier_cb - Clock rate change callback 1101 * @nb: Pointer to notifier block 1102 * @event: Notification reason 1103 * @data: Pointer to notification data object 1104 * 1105 * This function is called when the cdns_i2c input clock frequency changes. 1106 * The callback checks whether a valid bus frequency can be generated after the 1107 * change. If so, the change is acknowledged, otherwise the change is aborted. 1108 * New dividers are written to the HW in the pre- or post change notification 1109 * depending on the scaling direction. 1110 * 1111 * Return: NOTIFY_STOP if the rate change should be aborted, NOTIFY_OK 1112 * to acknowledge the change, NOTIFY_DONE if the notification is 1113 * considered irrelevant. 1114 */ 1115 static int cdns_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long 1116 event, void *data) 1117 { 1118 struct clk_notifier_data *ndata = data; 1119 struct cdns_i2c *id = to_cdns_i2c(nb); 1120 1121 if (pm_runtime_suspended(id->dev)) 1122 return NOTIFY_OK; 1123 1124 switch (event) { 1125 case PRE_RATE_CHANGE: 1126 { 1127 unsigned long input_clk = ndata->new_rate; 1128 unsigned long fscl = id->i2c_clk; 1129 unsigned int div_a, div_b; 1130 int ret; 1131 1132 ret = cdns_i2c_calc_divs(&fscl, input_clk, &div_a, &div_b); 1133 if (ret) { 1134 dev_warn(id->adap.dev.parent, 1135 "clock rate change rejected\n"); 1136 return NOTIFY_STOP; 1137 } 1138 1139 /* scale up */ 1140 if (ndata->new_rate > ndata->old_rate) 1141 cdns_i2c_setclk(ndata->new_rate, id); 1142 1143 return NOTIFY_OK; 1144 } 1145 case POST_RATE_CHANGE: 1146 id->input_clk = ndata->new_rate; 1147 /* scale down */ 1148 if (ndata->new_rate < ndata->old_rate) 1149 cdns_i2c_setclk(ndata->new_rate, id); 1150 return NOTIFY_OK; 1151 case ABORT_RATE_CHANGE: 1152 /* scale up */ 1153 if (ndata->new_rate > ndata->old_rate) 1154 cdns_i2c_setclk(ndata->old_rate, id); 1155 return NOTIFY_OK; 1156 default: 1157 return NOTIFY_DONE; 1158 } 1159 } 1160 1161 /** 1162 * cdns_i2c_runtime_suspend - Runtime suspend method for the driver 1163 * @dev: Address of the platform_device structure 1164 * 1165 * Put the driver into low power mode. 1166 * 1167 * Return: 0 always 1168 */ 1169 static int __maybe_unused cdns_i2c_runtime_suspend(struct device *dev) 1170 { 1171 struct cdns_i2c *xi2c = dev_get_drvdata(dev); 1172 1173 clk_disable(xi2c->clk); 1174 1175 return 0; 1176 } 1177 1178 /** 1179 * cdns_i2c_init - Controller initialisation 1180 * @id: Device private data structure 1181 * 1182 * Initialise the i2c controller. 1183 * 1184 */ 1185 static void cdns_i2c_init(struct cdns_i2c *id) 1186 { 1187 cdns_i2c_writereg(id->ctrl_reg, CDNS_I2C_CR_OFFSET); 1188 /* 1189 * Cadence I2C controller has a bug wherein it generates 1190 * invalid read transaction after HW timeout in master receiver mode. 1191 * HW timeout is not used by this driver and the interrupt is disabled. 1192 * But the feature itself cannot be disabled. Hence maximum value 1193 * is written to this register to reduce the chances of error. 1194 */ 1195 cdns_i2c_writereg(CDNS_I2C_TIMEOUT_MAX, CDNS_I2C_TIME_OUT_OFFSET); 1196 } 1197 1198 /** 1199 * cdns_i2c_runtime_resume - Runtime resume 1200 * @dev: Address of the platform_device structure 1201 * 1202 * Runtime resume callback. 1203 * 1204 * Return: 0 on success and error value on error 1205 */ 1206 static int __maybe_unused cdns_i2c_runtime_resume(struct device *dev) 1207 { 1208 struct cdns_i2c *xi2c = dev_get_drvdata(dev); 1209 int ret; 1210 1211 ret = clk_enable(xi2c->clk); 1212 if (ret) { 1213 dev_err(dev, "Cannot enable clock.\n"); 1214 return ret; 1215 } 1216 cdns_i2c_init(xi2c); 1217 1218 return 0; 1219 } 1220 1221 static const struct dev_pm_ops cdns_i2c_dev_pm_ops = { 1222 SET_RUNTIME_PM_OPS(cdns_i2c_runtime_suspend, 1223 cdns_i2c_runtime_resume, NULL) 1224 }; 1225 1226 static const struct cdns_platform_data r1p10_i2c_def = { 1227 .quirks = CDNS_I2C_BROKEN_HOLD_BIT, 1228 }; 1229 1230 static const struct of_device_id cdns_i2c_of_match[] = { 1231 { .compatible = "cdns,i2c-r1p10", .data = &r1p10_i2c_def }, 1232 { .compatible = "cdns,i2c-r1p14",}, 1233 { /* end of table */ } 1234 }; 1235 MODULE_DEVICE_TABLE(of, cdns_i2c_of_match); 1236 1237 /** 1238 * cdns_i2c_detect_transfer_size - Detect the maximum transfer size supported 1239 * @id: Device private data structure 1240 * 1241 * Detect the maximum transfer size that is supported by this instance of the 1242 * Cadence I2C controller. 1243 */ 1244 static void cdns_i2c_detect_transfer_size(struct cdns_i2c *id) 1245 { 1246 u32 val; 1247 1248 /* 1249 * Writing to the transfer size register is only possible if these two bits 1250 * are set in the control register. 1251 */ 1252 cdns_i2c_writereg(CDNS_I2C_CR_MS | CDNS_I2C_CR_RW, CDNS_I2C_CR_OFFSET); 1253 1254 /* 1255 * The number of writable bits of the transfer size register can be between 1256 * 4 and 8. This is a controlled through a synthesis parameter of the IP 1257 * core and can vary from instance to instance. The unused MSBs always read 1258 * back as 0. Writing 0xff and then reading the value back will report the 1259 * maximum supported transfer size. 1260 */ 1261 cdns_i2c_writereg(CDNS_I2C_MAX_TRANSFER_SIZE, CDNS_I2C_XFER_SIZE_OFFSET); 1262 val = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); 1263 id->transfer_size = CDNS_I2C_TRANSFER_SIZE(val); 1264 cdns_i2c_writereg(0, CDNS_I2C_XFER_SIZE_OFFSET); 1265 cdns_i2c_writereg(0, CDNS_I2C_CR_OFFSET); 1266 } 1267 1268 /** 1269 * cdns_i2c_probe - Platform registration call 1270 * @pdev: Handle to the platform device structure 1271 * 1272 * This function does all the memory allocation and registration for the i2c 1273 * device. User can modify the address mode to 10 bit address mode using the 1274 * ioctl call with option I2C_TENBIT. 1275 * 1276 * Return: 0 on success, negative error otherwise 1277 */ 1278 static int cdns_i2c_probe(struct platform_device *pdev) 1279 { 1280 struct resource *r_mem; 1281 struct cdns_i2c *id; 1282 int ret, irq; 1283 const struct of_device_id *match; 1284 1285 id = devm_kzalloc(&pdev->dev, sizeof(*id), GFP_KERNEL); 1286 if (!id) 1287 return -ENOMEM; 1288 1289 id->dev = &pdev->dev; 1290 platform_set_drvdata(pdev, id); 1291 1292 match = of_match_node(cdns_i2c_of_match, pdev->dev.of_node); 1293 if (match && match->data) { 1294 const struct cdns_platform_data *data = match->data; 1295 id->quirks = data->quirks; 1296 } 1297 1298 id->rinfo.pinctrl = devm_pinctrl_get(&pdev->dev); 1299 if (IS_ERR(id->rinfo.pinctrl)) { 1300 int err = PTR_ERR(id->rinfo.pinctrl); 1301 1302 dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n"); 1303 if (err != -ENODEV) 1304 return err; 1305 } else { 1306 id->adap.bus_recovery_info = &id->rinfo; 1307 } 1308 1309 id->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r_mem); 1310 if (IS_ERR(id->membase)) 1311 return PTR_ERR(id->membase); 1312 1313 irq = platform_get_irq(pdev, 0); 1314 if (irq < 0) 1315 return irq; 1316 1317 id->adap.owner = THIS_MODULE; 1318 id->adap.dev.of_node = pdev->dev.of_node; 1319 id->adap.algo = &cdns_i2c_algo; 1320 id->adap.timeout = CDNS_I2C_TIMEOUT; 1321 id->adap.retries = 3; /* Default retry value. */ 1322 id->adap.algo_data = id; 1323 id->adap.dev.parent = &pdev->dev; 1324 init_completion(&id->xfer_done); 1325 snprintf(id->adap.name, sizeof(id->adap.name), 1326 "Cadence I2C at %08lx", (unsigned long)r_mem->start); 1327 1328 id->clk = devm_clk_get(&pdev->dev, NULL); 1329 if (IS_ERR(id->clk)) 1330 return dev_err_probe(&pdev->dev, PTR_ERR(id->clk), 1331 "input clock not found.\n"); 1332 1333 id->reset = devm_reset_control_get_optional_shared(&pdev->dev, NULL); 1334 if (IS_ERR(id->reset)) 1335 return dev_err_probe(&pdev->dev, PTR_ERR(id->reset), 1336 "Failed to request reset.\n"); 1337 1338 ret = clk_prepare_enable(id->clk); 1339 if (ret) 1340 dev_err(&pdev->dev, "Unable to enable clock.\n"); 1341 1342 ret = reset_control_deassert(id->reset); 1343 if (ret) { 1344 dev_err_probe(&pdev->dev, ret, 1345 "Failed to de-assert reset.\n"); 1346 goto err_clk_dis; 1347 } 1348 1349 pm_runtime_set_autosuspend_delay(id->dev, CNDS_I2C_PM_TIMEOUT); 1350 pm_runtime_use_autosuspend(id->dev); 1351 pm_runtime_set_active(id->dev); 1352 pm_runtime_enable(id->dev); 1353 1354 id->clk_rate_change_nb.notifier_call = cdns_i2c_clk_notifier_cb; 1355 if (clk_notifier_register(id->clk, &id->clk_rate_change_nb)) 1356 dev_warn(&pdev->dev, "Unable to register clock notifier.\n"); 1357 id->input_clk = clk_get_rate(id->clk); 1358 1359 ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency", 1360 &id->i2c_clk); 1361 if (ret || (id->i2c_clk > I2C_MAX_FAST_MODE_FREQ)) 1362 id->i2c_clk = I2C_MAX_STANDARD_MODE_FREQ; 1363 1364 #if IS_ENABLED(CONFIG_I2C_SLAVE) 1365 /* Set initial mode to master */ 1366 id->dev_mode = CDNS_I2C_MODE_MASTER; 1367 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 1368 #endif 1369 id->ctrl_reg = CDNS_I2C_CR_ACK_EN | CDNS_I2C_CR_NEA | CDNS_I2C_CR_MS; 1370 1371 id->fifo_depth = CDNS_I2C_FIFO_DEPTH_DEFAULT; 1372 of_property_read_u32(pdev->dev.of_node, "fifo-depth", &id->fifo_depth); 1373 1374 cdns_i2c_detect_transfer_size(id); 1375 1376 ret = cdns_i2c_setclk(id->input_clk, id); 1377 if (ret) { 1378 dev_err(&pdev->dev, "invalid SCL clock: %u Hz\n", id->i2c_clk); 1379 ret = -EINVAL; 1380 goto err_clk_notifier_unregister; 1381 } 1382 1383 ret = devm_request_irq(&pdev->dev, irq, cdns_i2c_isr, 0, 1384 DRIVER_NAME, id); 1385 if (ret) { 1386 dev_err(&pdev->dev, "cannot get irq %d\n", irq); 1387 goto err_clk_notifier_unregister; 1388 } 1389 cdns_i2c_init(id); 1390 1391 ret = i2c_add_adapter(&id->adap); 1392 if (ret < 0) 1393 goto err_clk_notifier_unregister; 1394 1395 dev_info(&pdev->dev, "%u kHz mmio %08lx irq %d\n", 1396 id->i2c_clk / 1000, (unsigned long)r_mem->start, irq); 1397 1398 return 0; 1399 1400 err_clk_notifier_unregister: 1401 clk_notifier_unregister(id->clk, &id->clk_rate_change_nb); 1402 reset_control_assert(id->reset); 1403 err_clk_dis: 1404 clk_disable_unprepare(id->clk); 1405 pm_runtime_disable(&pdev->dev); 1406 pm_runtime_set_suspended(&pdev->dev); 1407 return ret; 1408 } 1409 1410 /** 1411 * cdns_i2c_remove - Unregister the device after releasing the resources 1412 * @pdev: Handle to the platform device structure 1413 * 1414 * This function frees all the resources allocated to the device. 1415 * 1416 * Return: 0 always 1417 */ 1418 static void cdns_i2c_remove(struct platform_device *pdev) 1419 { 1420 struct cdns_i2c *id = platform_get_drvdata(pdev); 1421 1422 pm_runtime_disable(&pdev->dev); 1423 pm_runtime_set_suspended(&pdev->dev); 1424 pm_runtime_dont_use_autosuspend(&pdev->dev); 1425 1426 i2c_del_adapter(&id->adap); 1427 clk_notifier_unregister(id->clk, &id->clk_rate_change_nb); 1428 reset_control_assert(id->reset); 1429 clk_disable_unprepare(id->clk); 1430 } 1431 1432 static struct platform_driver cdns_i2c_drv = { 1433 .driver = { 1434 .name = DRIVER_NAME, 1435 .of_match_table = cdns_i2c_of_match, 1436 .pm = &cdns_i2c_dev_pm_ops, 1437 }, 1438 .probe = cdns_i2c_probe, 1439 .remove_new = cdns_i2c_remove, 1440 }; 1441 1442 module_platform_driver(cdns_i2c_drv); 1443 1444 MODULE_AUTHOR("Xilinx Inc."); 1445 MODULE_DESCRIPTION("Cadence I2C bus driver"); 1446 MODULE_LICENSE("GPL"); 1447