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/module.h> 14 #include <linux/platform_device.h> 15 #include <linux/of.h> 16 #include <linux/pm_runtime.h> 17 18 /* Register offsets for the I2C device. */ 19 #define CDNS_I2C_CR_OFFSET 0x00 /* Control Register, RW */ 20 #define CDNS_I2C_SR_OFFSET 0x04 /* Status Register, RO */ 21 #define CDNS_I2C_ADDR_OFFSET 0x08 /* I2C Address Register, RW */ 22 #define CDNS_I2C_DATA_OFFSET 0x0C /* I2C Data Register, RW */ 23 #define CDNS_I2C_ISR_OFFSET 0x10 /* IRQ Status Register, RW */ 24 #define CDNS_I2C_XFER_SIZE_OFFSET 0x14 /* Transfer Size Register, RW */ 25 #define CDNS_I2C_TIME_OUT_OFFSET 0x1C /* Time Out Register, RW */ 26 #define CDNS_I2C_IMR_OFFSET 0x20 /* IRQ Mask Register, RO */ 27 #define CDNS_I2C_IER_OFFSET 0x24 /* IRQ Enable Register, WO */ 28 #define CDNS_I2C_IDR_OFFSET 0x28 /* IRQ Disable Register, WO */ 29 30 /* Control Register Bit mask definitions */ 31 #define CDNS_I2C_CR_HOLD BIT(4) /* Hold Bus bit */ 32 #define CDNS_I2C_CR_ACK_EN BIT(3) 33 #define CDNS_I2C_CR_NEA BIT(2) 34 #define CDNS_I2C_CR_MS BIT(1) 35 /* Read or Write Master transfer 0 = Transmitter, 1 = Receiver */ 36 #define CDNS_I2C_CR_RW BIT(0) 37 /* 1 = Auto init FIFO to zeroes */ 38 #define CDNS_I2C_CR_CLR_FIFO BIT(6) 39 #define CDNS_I2C_CR_DIVA_SHIFT 14 40 #define CDNS_I2C_CR_DIVA_MASK (3 << CDNS_I2C_CR_DIVA_SHIFT) 41 #define CDNS_I2C_CR_DIVB_SHIFT 8 42 #define CDNS_I2C_CR_DIVB_MASK (0x3f << CDNS_I2C_CR_DIVB_SHIFT) 43 44 #define CDNS_I2C_CR_MASTER_EN_MASK (CDNS_I2C_CR_NEA | \ 45 CDNS_I2C_CR_ACK_EN | \ 46 CDNS_I2C_CR_MS) 47 48 #define CDNS_I2C_CR_SLAVE_EN_MASK ~CDNS_I2C_CR_MASTER_EN_MASK 49 50 /* Status Register Bit mask definitions */ 51 #define CDNS_I2C_SR_BA BIT(8) 52 #define CDNS_I2C_SR_TXDV BIT(6) 53 #define CDNS_I2C_SR_RXDV BIT(5) 54 #define CDNS_I2C_SR_RXRW BIT(3) 55 56 /* 57 * I2C Address Register Bit mask definitions 58 * Normal addressing mode uses [6:0] bits. Extended addressing mode uses [9:0] 59 * bits. A write access to this register always initiates a transfer if the I2C 60 * is in master mode. 61 */ 62 #define CDNS_I2C_ADDR_MASK 0x000003FF /* I2C Address Mask */ 63 64 /* 65 * I2C Interrupt Registers Bit mask definitions 66 * All the four interrupt registers (Status/Mask/Enable/Disable) have the same 67 * bit definitions. 68 */ 69 #define CDNS_I2C_IXR_ARB_LOST BIT(9) 70 #define CDNS_I2C_IXR_RX_UNF BIT(7) 71 #define CDNS_I2C_IXR_TX_OVF BIT(6) 72 #define CDNS_I2C_IXR_RX_OVF BIT(5) 73 #define CDNS_I2C_IXR_SLV_RDY BIT(4) 74 #define CDNS_I2C_IXR_TO BIT(3) 75 #define CDNS_I2C_IXR_NACK BIT(2) 76 #define CDNS_I2C_IXR_DATA BIT(1) 77 #define CDNS_I2C_IXR_COMP BIT(0) 78 79 #define CDNS_I2C_IXR_ALL_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \ 80 CDNS_I2C_IXR_RX_UNF | \ 81 CDNS_I2C_IXR_TX_OVF | \ 82 CDNS_I2C_IXR_RX_OVF | \ 83 CDNS_I2C_IXR_SLV_RDY | \ 84 CDNS_I2C_IXR_TO | \ 85 CDNS_I2C_IXR_NACK | \ 86 CDNS_I2C_IXR_DATA | \ 87 CDNS_I2C_IXR_COMP) 88 89 #define CDNS_I2C_IXR_ERR_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \ 90 CDNS_I2C_IXR_RX_UNF | \ 91 CDNS_I2C_IXR_TX_OVF | \ 92 CDNS_I2C_IXR_RX_OVF | \ 93 CDNS_I2C_IXR_NACK) 94 95 #define CDNS_I2C_ENABLED_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \ 96 CDNS_I2C_IXR_RX_UNF | \ 97 CDNS_I2C_IXR_TX_OVF | \ 98 CDNS_I2C_IXR_RX_OVF | \ 99 CDNS_I2C_IXR_NACK | \ 100 CDNS_I2C_IXR_DATA | \ 101 CDNS_I2C_IXR_COMP) 102 103 #define CDNS_I2C_IXR_SLAVE_INTR_MASK (CDNS_I2C_IXR_RX_UNF | \ 104 CDNS_I2C_IXR_TX_OVF | \ 105 CDNS_I2C_IXR_RX_OVF | \ 106 CDNS_I2C_IXR_TO | \ 107 CDNS_I2C_IXR_NACK | \ 108 CDNS_I2C_IXR_DATA | \ 109 CDNS_I2C_IXR_COMP) 110 111 #define CDNS_I2C_TIMEOUT msecs_to_jiffies(1000) 112 /* timeout for pm runtime autosuspend */ 113 #define CNDS_I2C_PM_TIMEOUT 1000 /* ms */ 114 115 #define CDNS_I2C_FIFO_DEPTH 16 116 /* FIFO depth at which the DATA interrupt occurs */ 117 #define CDNS_I2C_DATA_INTR_DEPTH (CDNS_I2C_FIFO_DEPTH - 2) 118 #define CDNS_I2C_MAX_TRANSFER_SIZE 255 119 /* Transfer size in multiples of data interrupt depth */ 120 #define CDNS_I2C_TRANSFER_SIZE (CDNS_I2C_MAX_TRANSFER_SIZE - 3) 121 122 #define DRIVER_NAME "cdns-i2c" 123 124 #define CDNS_I2C_DIVA_MAX 4 125 #define CDNS_I2C_DIVB_MAX 64 126 127 #define CDNS_I2C_TIMEOUT_MAX 0xFF 128 129 #define CDNS_I2C_BROKEN_HOLD_BIT BIT(0) 130 131 #define cdns_i2c_readreg(offset) readl_relaxed(id->membase + offset) 132 #define cdns_i2c_writereg(val, offset) writel_relaxed(val, id->membase + offset) 133 134 #if IS_ENABLED(CONFIG_I2C_SLAVE) 135 /** 136 * enum cdns_i2c_mode - I2C Controller current operating mode 137 * 138 * @CDNS_I2C_MODE_SLAVE: I2C controller operating in slave mode 139 * @CDNS_I2C_MODE_MASTER: I2C Controller operating in master mode 140 */ 141 enum cdns_i2c_mode { 142 CDNS_I2C_MODE_SLAVE, 143 CDNS_I2C_MODE_MASTER, 144 }; 145 146 /** 147 * enum cdns_i2c_slave_state - Slave state when I2C is operating in slave mode 148 * 149 * @CDNS_I2C_SLAVE_STATE_IDLE: I2C slave idle 150 * @CDNS_I2C_SLAVE_STATE_SEND: I2C slave sending data to master 151 * @CDNS_I2C_SLAVE_STATE_RECV: I2C slave receiving data from master 152 */ 153 enum cdns_i2c_slave_state { 154 CDNS_I2C_SLAVE_STATE_IDLE, 155 CDNS_I2C_SLAVE_STATE_SEND, 156 CDNS_I2C_SLAVE_STATE_RECV, 157 }; 158 #endif 159 160 /** 161 * struct cdns_i2c - I2C device private data structure 162 * 163 * @dev: Pointer to device structure 164 * @membase: Base address of the I2C device 165 * @adap: I2C adapter instance 166 * @p_msg: Message pointer 167 * @err_status: Error status in Interrupt Status Register 168 * @xfer_done: Transfer complete status 169 * @p_send_buf: Pointer to transmit buffer 170 * @p_recv_buf: Pointer to receive buffer 171 * @send_count: Number of bytes still expected to send 172 * @recv_count: Number of bytes still expected to receive 173 * @curr_recv_count: Number of bytes to be received in current transfer 174 * @irq: IRQ number 175 * @input_clk: Input clock to I2C controller 176 * @i2c_clk: Maximum I2C clock speed 177 * @bus_hold_flag: Flag used in repeated start for clearing HOLD bit 178 * @clk: Pointer to struct clk 179 * @clk_rate_change_nb: Notifier block for clock rate changes 180 * @quirks: flag for broken hold bit usage in r1p10 181 * @ctrl_reg: Cached value of the control register. 182 * @ctrl_reg_diva_divb: value of fields DIV_A and DIV_B from CR register 183 * @slave: Registered slave instance. 184 * @dev_mode: I2C operating role(master/slave). 185 * @slave_state: I2C Slave state(idle/read/write). 186 */ 187 struct cdns_i2c { 188 struct device *dev; 189 void __iomem *membase; 190 struct i2c_adapter adap; 191 struct i2c_msg *p_msg; 192 int err_status; 193 struct completion xfer_done; 194 unsigned char *p_send_buf; 195 unsigned char *p_recv_buf; 196 unsigned int send_count; 197 unsigned int recv_count; 198 unsigned int curr_recv_count; 199 int irq; 200 unsigned long input_clk; 201 unsigned int i2c_clk; 202 unsigned int bus_hold_flag; 203 struct clk *clk; 204 struct notifier_block clk_rate_change_nb; 205 u32 quirks; 206 u32 ctrl_reg; 207 #if IS_ENABLED(CONFIG_I2C_SLAVE) 208 u16 ctrl_reg_diva_divb; 209 struct i2c_client *slave; 210 enum cdns_i2c_mode dev_mode; 211 enum cdns_i2c_slave_state slave_state; 212 #endif 213 }; 214 215 struct cdns_platform_data { 216 u32 quirks; 217 }; 218 219 #define to_cdns_i2c(_nb) container_of(_nb, struct cdns_i2c, \ 220 clk_rate_change_nb) 221 222 /** 223 * cdns_i2c_clear_bus_hold - Clear bus hold bit 224 * @id: Pointer to driver data struct 225 * 226 * Helper to clear the controller's bus hold bit. 227 */ 228 static void cdns_i2c_clear_bus_hold(struct cdns_i2c *id) 229 { 230 u32 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 231 if (reg & CDNS_I2C_CR_HOLD) 232 cdns_i2c_writereg(reg & ~CDNS_I2C_CR_HOLD, CDNS_I2C_CR_OFFSET); 233 } 234 235 static inline bool cdns_is_holdquirk(struct cdns_i2c *id, bool hold_wrkaround) 236 { 237 return (hold_wrkaround && 238 (id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1)); 239 } 240 241 #if IS_ENABLED(CONFIG_I2C_SLAVE) 242 static void cdns_i2c_set_mode(enum cdns_i2c_mode mode, struct cdns_i2c *id) 243 { 244 /* Disable all interrupts */ 245 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET); 246 247 /* Clear FIFO and transfer size */ 248 cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET); 249 250 /* Update device mode and state */ 251 id->dev_mode = mode; 252 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 253 254 switch (mode) { 255 case CDNS_I2C_MODE_MASTER: 256 /* Enable i2c master */ 257 cdns_i2c_writereg(id->ctrl_reg_diva_divb | 258 CDNS_I2C_CR_MASTER_EN_MASK, 259 CDNS_I2C_CR_OFFSET); 260 /* 261 * This delay is needed to give the IP some time to switch to 262 * the master mode. With lower values(like 110 us) i2cdetect 263 * will not detect any slave and without this delay, the IP will 264 * trigger a timeout interrupt. 265 */ 266 usleep_range(115, 125); 267 break; 268 case CDNS_I2C_MODE_SLAVE: 269 /* Enable i2c slave */ 270 cdns_i2c_writereg(id->ctrl_reg_diva_divb & 271 CDNS_I2C_CR_SLAVE_EN_MASK, 272 CDNS_I2C_CR_OFFSET); 273 274 /* Setting slave address */ 275 cdns_i2c_writereg(id->slave->addr & CDNS_I2C_ADDR_MASK, 276 CDNS_I2C_ADDR_OFFSET); 277 278 /* Enable slave send/receive interrupts */ 279 cdns_i2c_writereg(CDNS_I2C_IXR_SLAVE_INTR_MASK, 280 CDNS_I2C_IER_OFFSET); 281 break; 282 } 283 } 284 285 static void cdns_i2c_slave_rcv_data(struct cdns_i2c *id) 286 { 287 u8 bytes; 288 unsigned char data; 289 290 /* Prepare backend for data reception */ 291 if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) { 292 id->slave_state = CDNS_I2C_SLAVE_STATE_RECV; 293 i2c_slave_event(id->slave, I2C_SLAVE_WRITE_REQUESTED, NULL); 294 } 295 296 /* Fetch number of bytes to receive */ 297 bytes = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); 298 299 /* Read data and send to backend */ 300 while (bytes--) { 301 data = cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET); 302 i2c_slave_event(id->slave, I2C_SLAVE_WRITE_RECEIVED, &data); 303 } 304 } 305 306 static void cdns_i2c_slave_send_data(struct cdns_i2c *id) 307 { 308 u8 data; 309 310 /* Prepare backend for data transmission */ 311 if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) { 312 id->slave_state = CDNS_I2C_SLAVE_STATE_SEND; 313 i2c_slave_event(id->slave, I2C_SLAVE_READ_REQUESTED, &data); 314 } else { 315 i2c_slave_event(id->slave, I2C_SLAVE_READ_PROCESSED, &data); 316 } 317 318 /* Send data over bus */ 319 cdns_i2c_writereg(data, CDNS_I2C_DATA_OFFSET); 320 } 321 322 /** 323 * cdns_i2c_slave_isr - Interrupt handler for the I2C device in slave role 324 * @ptr: Pointer to I2C device private data 325 * 326 * This function handles the data interrupt and transfer complete interrupt of 327 * the I2C device in slave role. 328 * 329 * Return: IRQ_HANDLED always 330 */ 331 static irqreturn_t cdns_i2c_slave_isr(void *ptr) 332 { 333 struct cdns_i2c *id = ptr; 334 unsigned int isr_status, i2c_status; 335 336 /* Fetch the interrupt status */ 337 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 338 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); 339 340 /* Ignore masked interrupts */ 341 isr_status &= ~cdns_i2c_readreg(CDNS_I2C_IMR_OFFSET); 342 343 /* Fetch transfer mode (send/receive) */ 344 i2c_status = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET); 345 346 /* Handle data send/receive */ 347 if (i2c_status & CDNS_I2C_SR_RXRW) { 348 /* Send data to master */ 349 if (isr_status & CDNS_I2C_IXR_DATA) 350 cdns_i2c_slave_send_data(id); 351 352 if (isr_status & CDNS_I2C_IXR_COMP) { 353 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 354 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL); 355 } 356 } else { 357 /* Receive data from master */ 358 if (isr_status & CDNS_I2C_IXR_DATA) 359 cdns_i2c_slave_rcv_data(id); 360 361 if (isr_status & CDNS_I2C_IXR_COMP) { 362 cdns_i2c_slave_rcv_data(id); 363 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 364 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL); 365 } 366 } 367 368 /* Master indicated xfer stop or fifo underflow/overflow */ 369 if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_RX_OVF | 370 CDNS_I2C_IXR_RX_UNF | CDNS_I2C_IXR_TX_OVF)) { 371 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 372 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL); 373 cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET); 374 } 375 376 return IRQ_HANDLED; 377 } 378 #endif 379 380 /** 381 * cdns_i2c_master_isr - Interrupt handler for the I2C device in master role 382 * @ptr: Pointer to I2C device private data 383 * 384 * This function handles the data interrupt, transfer complete interrupt and 385 * the error interrupts of the I2C device in master role. 386 * 387 * Return: IRQ_HANDLED always 388 */ 389 static irqreturn_t cdns_i2c_master_isr(void *ptr) 390 { 391 unsigned int isr_status, avail_bytes; 392 unsigned int bytes_to_send; 393 bool updatetx; 394 struct cdns_i2c *id = ptr; 395 /* Signal completion only after everything is updated */ 396 int done_flag = 0; 397 irqreturn_t status = IRQ_NONE; 398 399 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 400 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); 401 id->err_status = 0; 402 403 /* Handling nack and arbitration lost interrupt */ 404 if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_ARB_LOST)) { 405 done_flag = 1; 406 status = IRQ_HANDLED; 407 } 408 409 /* 410 * Check if transfer size register needs to be updated again for a 411 * large data receive operation. 412 */ 413 updatetx = id->recv_count > id->curr_recv_count; 414 415 /* When receiving, handle data interrupt and completion interrupt */ 416 if (id->p_recv_buf && 417 ((isr_status & CDNS_I2C_IXR_COMP) || 418 (isr_status & CDNS_I2C_IXR_DATA))) { 419 /* Read data if receive data valid is set */ 420 while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & 421 CDNS_I2C_SR_RXDV) { 422 if (id->recv_count > 0) { 423 *(id->p_recv_buf)++ = 424 cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET); 425 id->recv_count--; 426 id->curr_recv_count--; 427 428 /* 429 * Clear hold bit that was set for FIFO control 430 * if RX data left is less than or equal to 431 * FIFO DEPTH unless repeated start is selected 432 */ 433 if (id->recv_count <= CDNS_I2C_FIFO_DEPTH && 434 !id->bus_hold_flag) 435 cdns_i2c_clear_bus_hold(id); 436 437 } else { 438 dev_err(id->adap.dev.parent, 439 "xfer_size reg rollover. xfer aborted!\n"); 440 id->err_status |= CDNS_I2C_IXR_TO; 441 break; 442 } 443 444 if (cdns_is_holdquirk(id, updatetx)) 445 break; 446 } 447 448 /* 449 * The controller sends NACK to the slave when transfer size 450 * register reaches zero without considering the HOLD bit. 451 * This workaround is implemented for large data transfers to 452 * maintain transfer size non-zero while performing a large 453 * receive operation. 454 */ 455 if (cdns_is_holdquirk(id, updatetx)) { 456 /* wait while fifo is full */ 457 while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) != 458 (id->curr_recv_count - CDNS_I2C_FIFO_DEPTH)) 459 ; 460 461 /* 462 * Check number of bytes to be received against maximum 463 * transfer size and update register accordingly. 464 */ 465 if (((int)(id->recv_count) - CDNS_I2C_FIFO_DEPTH) > 466 CDNS_I2C_TRANSFER_SIZE) { 467 cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE, 468 CDNS_I2C_XFER_SIZE_OFFSET); 469 id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE + 470 CDNS_I2C_FIFO_DEPTH; 471 } else { 472 cdns_i2c_writereg(id->recv_count - 473 CDNS_I2C_FIFO_DEPTH, 474 CDNS_I2C_XFER_SIZE_OFFSET); 475 id->curr_recv_count = id->recv_count; 476 } 477 } 478 479 /* Clear hold (if not repeated start) and signal completion */ 480 if ((isr_status & CDNS_I2C_IXR_COMP) && !id->recv_count) { 481 if (!id->bus_hold_flag) 482 cdns_i2c_clear_bus_hold(id); 483 done_flag = 1; 484 } 485 486 status = IRQ_HANDLED; 487 } 488 489 /* When sending, handle transfer complete interrupt */ 490 if ((isr_status & CDNS_I2C_IXR_COMP) && !id->p_recv_buf) { 491 /* 492 * If there is more data to be sent, calculate the 493 * space available in FIFO and fill with that many bytes. 494 */ 495 if (id->send_count) { 496 avail_bytes = CDNS_I2C_FIFO_DEPTH - 497 cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); 498 if (id->send_count > avail_bytes) 499 bytes_to_send = avail_bytes; 500 else 501 bytes_to_send = id->send_count; 502 503 while (bytes_to_send--) { 504 cdns_i2c_writereg( 505 (*(id->p_send_buf)++), 506 CDNS_I2C_DATA_OFFSET); 507 id->send_count--; 508 } 509 } else { 510 /* 511 * Signal the completion of transaction and 512 * clear the hold bus bit if there are no 513 * further messages to be processed. 514 */ 515 done_flag = 1; 516 } 517 if (!id->send_count && !id->bus_hold_flag) 518 cdns_i2c_clear_bus_hold(id); 519 520 status = IRQ_HANDLED; 521 } 522 523 /* Update the status for errors */ 524 id->err_status |= isr_status & CDNS_I2C_IXR_ERR_INTR_MASK; 525 if (id->err_status) 526 status = IRQ_HANDLED; 527 528 if (done_flag) 529 complete(&id->xfer_done); 530 531 return status; 532 } 533 534 /** 535 * cdns_i2c_isr - Interrupt handler for the I2C device 536 * @irq: irq number for the I2C device 537 * @ptr: void pointer to cdns_i2c structure 538 * 539 * This function passes the control to slave/master based on current role of 540 * i2c controller. 541 * 542 * Return: IRQ_HANDLED always 543 */ 544 static irqreturn_t cdns_i2c_isr(int irq, void *ptr) 545 { 546 #if IS_ENABLED(CONFIG_I2C_SLAVE) 547 struct cdns_i2c *id = ptr; 548 549 if (id->dev_mode == CDNS_I2C_MODE_SLAVE) 550 return cdns_i2c_slave_isr(ptr); 551 #endif 552 return cdns_i2c_master_isr(ptr); 553 } 554 555 /** 556 * cdns_i2c_mrecv - Prepare and start a master receive operation 557 * @id: pointer to the i2c device structure 558 */ 559 static void cdns_i2c_mrecv(struct cdns_i2c *id) 560 { 561 unsigned int ctrl_reg; 562 unsigned int isr_status; 563 unsigned long flags; 564 bool hold_clear = false; 565 bool irq_save = false; 566 567 u32 addr; 568 569 id->p_recv_buf = id->p_msg->buf; 570 id->recv_count = id->p_msg->len; 571 572 /* Put the controller in master receive mode and clear the FIFO */ 573 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 574 ctrl_reg |= CDNS_I2C_CR_RW | CDNS_I2C_CR_CLR_FIFO; 575 576 /* 577 * Receive up to I2C_SMBUS_BLOCK_MAX data bytes, plus one message length 578 * byte, plus one checksum byte if PEC is enabled. p_msg->len will be 2 if 579 * PEC is enabled, otherwise 1. 580 */ 581 if (id->p_msg->flags & I2C_M_RECV_LEN) 582 id->recv_count = I2C_SMBUS_BLOCK_MAX + id->p_msg->len; 583 584 id->curr_recv_count = id->recv_count; 585 586 /* 587 * Check for the message size against FIFO depth and set the 588 * 'hold bus' bit if it is greater than FIFO depth. 589 */ 590 if (id->recv_count > CDNS_I2C_FIFO_DEPTH) 591 ctrl_reg |= CDNS_I2C_CR_HOLD; 592 593 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); 594 595 /* Clear the interrupts in interrupt status register */ 596 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 597 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); 598 599 /* 600 * The no. of bytes to receive is checked against the limit of 601 * max transfer size. Set transfer size register with no of bytes 602 * receive if it is less than transfer size and transfer size if 603 * it is more. Enable the interrupts. 604 */ 605 if (id->recv_count > CDNS_I2C_TRANSFER_SIZE) { 606 cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE, 607 CDNS_I2C_XFER_SIZE_OFFSET); 608 id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE; 609 } else { 610 cdns_i2c_writereg(id->recv_count, CDNS_I2C_XFER_SIZE_OFFSET); 611 } 612 613 /* Determine hold_clear based on number of bytes to receive and hold flag */ 614 if (!id->bus_hold_flag && 615 ((id->p_msg->flags & I2C_M_RECV_LEN) != I2C_M_RECV_LEN) && 616 (id->recv_count <= CDNS_I2C_FIFO_DEPTH)) { 617 if (cdns_i2c_readreg(CDNS_I2C_CR_OFFSET) & CDNS_I2C_CR_HOLD) { 618 hold_clear = true; 619 if (id->quirks & CDNS_I2C_BROKEN_HOLD_BIT) 620 irq_save = true; 621 } 622 } 623 624 addr = id->p_msg->addr; 625 addr &= CDNS_I2C_ADDR_MASK; 626 627 if (hold_clear) { 628 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET) & ~CDNS_I2C_CR_HOLD; 629 /* 630 * In case of Xilinx Zynq SOC, clear the HOLD bit before transfer size 631 * register reaches '0'. This is an IP bug which causes transfer size 632 * register overflow to 0xFF. To satisfy this timing requirement, 633 * disable the interrupts on current processor core between register 634 * writes to slave address register and control register. 635 */ 636 if (irq_save) 637 local_irq_save(flags); 638 639 cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET); 640 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); 641 /* Read it back to avoid bufferring and make sure write happens */ 642 cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 643 644 if (irq_save) 645 local_irq_restore(flags); 646 } else { 647 cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET); 648 } 649 650 cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); 651 } 652 653 /** 654 * cdns_i2c_msend - Prepare and start a master send operation 655 * @id: pointer to the i2c device 656 */ 657 static void cdns_i2c_msend(struct cdns_i2c *id) 658 { 659 unsigned int avail_bytes; 660 unsigned int bytes_to_send; 661 unsigned int ctrl_reg; 662 unsigned int isr_status; 663 664 id->p_recv_buf = NULL; 665 id->p_send_buf = id->p_msg->buf; 666 id->send_count = id->p_msg->len; 667 668 /* Set the controller in Master transmit mode and clear the FIFO. */ 669 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 670 ctrl_reg &= ~CDNS_I2C_CR_RW; 671 ctrl_reg |= CDNS_I2C_CR_CLR_FIFO; 672 673 /* 674 * Check for the message size against FIFO depth and set the 675 * 'hold bus' bit if it is greater than FIFO depth. 676 */ 677 if (id->send_count > CDNS_I2C_FIFO_DEPTH) 678 ctrl_reg |= CDNS_I2C_CR_HOLD; 679 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); 680 681 /* Clear the interrupts in interrupt status register. */ 682 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 683 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); 684 685 /* 686 * Calculate the space available in FIFO. Check the message length 687 * against the space available, and fill the FIFO accordingly. 688 * Enable the interrupts. 689 */ 690 avail_bytes = CDNS_I2C_FIFO_DEPTH - 691 cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); 692 693 if (id->send_count > avail_bytes) 694 bytes_to_send = avail_bytes; 695 else 696 bytes_to_send = id->send_count; 697 698 while (bytes_to_send--) { 699 cdns_i2c_writereg((*(id->p_send_buf)++), CDNS_I2C_DATA_OFFSET); 700 id->send_count--; 701 } 702 703 /* 704 * Clear the bus hold flag if there is no more data 705 * and if it is the last message. 706 */ 707 if (!id->bus_hold_flag && !id->send_count) 708 cdns_i2c_clear_bus_hold(id); 709 /* Set the slave address in address register - triggers operation. */ 710 cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK, 711 CDNS_I2C_ADDR_OFFSET); 712 713 cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); 714 } 715 716 /** 717 * cdns_i2c_master_reset - Reset the interface 718 * @adap: pointer to the i2c adapter driver instance 719 * 720 * This function cleanup the fifos, clear the hold bit and status 721 * and disable the interrupts. 722 */ 723 static void cdns_i2c_master_reset(struct i2c_adapter *adap) 724 { 725 struct cdns_i2c *id = adap->algo_data; 726 u32 regval; 727 728 /* Disable the interrupts */ 729 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET); 730 /* Clear the hold bit and fifos */ 731 regval = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 732 regval &= ~CDNS_I2C_CR_HOLD; 733 regval |= CDNS_I2C_CR_CLR_FIFO; 734 cdns_i2c_writereg(regval, CDNS_I2C_CR_OFFSET); 735 /* Update the transfercount register to zero */ 736 cdns_i2c_writereg(0, CDNS_I2C_XFER_SIZE_OFFSET); 737 /* Clear the interrupt status register */ 738 regval = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); 739 cdns_i2c_writereg(regval, CDNS_I2C_ISR_OFFSET); 740 /* Clear the status register */ 741 regval = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET); 742 cdns_i2c_writereg(regval, CDNS_I2C_SR_OFFSET); 743 } 744 745 static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg, 746 struct i2c_adapter *adap) 747 { 748 unsigned long time_left, msg_timeout; 749 u32 reg; 750 751 id->p_msg = msg; 752 id->err_status = 0; 753 reinit_completion(&id->xfer_done); 754 755 /* Check for the TEN Bit mode on each msg */ 756 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 757 if (msg->flags & I2C_M_TEN) { 758 if (reg & CDNS_I2C_CR_NEA) 759 cdns_i2c_writereg(reg & ~CDNS_I2C_CR_NEA, 760 CDNS_I2C_CR_OFFSET); 761 } else { 762 if (!(reg & CDNS_I2C_CR_NEA)) 763 cdns_i2c_writereg(reg | CDNS_I2C_CR_NEA, 764 CDNS_I2C_CR_OFFSET); 765 } 766 767 /* Check for the R/W flag on each msg */ 768 if (msg->flags & I2C_M_RD) 769 cdns_i2c_mrecv(id); 770 else 771 cdns_i2c_msend(id); 772 773 /* Minimal time to execute this message */ 774 msg_timeout = msecs_to_jiffies((1000 * msg->len * BITS_PER_BYTE) / id->i2c_clk); 775 /* Plus some wiggle room */ 776 msg_timeout += msecs_to_jiffies(500); 777 778 if (msg_timeout < adap->timeout) 779 msg_timeout = adap->timeout; 780 781 /* Wait for the signal of completion */ 782 time_left = wait_for_completion_timeout(&id->xfer_done, msg_timeout); 783 if (time_left == 0) { 784 cdns_i2c_master_reset(adap); 785 dev_err(id->adap.dev.parent, 786 "timeout waiting on completion\n"); 787 return -ETIMEDOUT; 788 } 789 790 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, 791 CDNS_I2C_IDR_OFFSET); 792 793 /* If it is bus arbitration error, try again */ 794 if (id->err_status & CDNS_I2C_IXR_ARB_LOST) 795 return -EAGAIN; 796 797 if (msg->flags & I2C_M_RECV_LEN) 798 msg->len += min_t(unsigned int, msg->buf[0], I2C_SMBUS_BLOCK_MAX); 799 800 return 0; 801 } 802 803 /** 804 * cdns_i2c_master_xfer - The main i2c transfer function 805 * @adap: pointer to the i2c adapter driver instance 806 * @msgs: pointer to the i2c message structure 807 * @num: the number of messages to transfer 808 * 809 * Initiates the send/recv activity based on the transfer message received. 810 * 811 * Return: number of msgs processed on success, negative error otherwise 812 */ 813 static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 814 int num) 815 { 816 int ret, count; 817 u32 reg; 818 struct cdns_i2c *id = adap->algo_data; 819 bool hold_quirk; 820 #if IS_ENABLED(CONFIG_I2C_SLAVE) 821 bool change_role = false; 822 #endif 823 824 ret = pm_runtime_resume_and_get(id->dev); 825 if (ret < 0) 826 return ret; 827 828 #if IS_ENABLED(CONFIG_I2C_SLAVE) 829 /* Check i2c operating mode and switch if possible */ 830 if (id->dev_mode == CDNS_I2C_MODE_SLAVE) { 831 if (id->slave_state != CDNS_I2C_SLAVE_STATE_IDLE) 832 return -EAGAIN; 833 834 /* Set mode to master */ 835 cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id); 836 837 /* Mark flag to change role once xfer is completed */ 838 change_role = true; 839 } 840 #endif 841 842 /* Check if the bus is free */ 843 if (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & CDNS_I2C_SR_BA) { 844 ret = -EAGAIN; 845 goto out; 846 } 847 848 hold_quirk = !!(id->quirks & CDNS_I2C_BROKEN_HOLD_BIT); 849 /* 850 * Set the flag to one when multiple messages are to be 851 * processed with a repeated start. 852 */ 853 if (num > 1) { 854 /* 855 * This controller does not give completion interrupt after a 856 * master receive message if HOLD bit is set (repeated start), 857 * resulting in SW timeout. Hence, if a receive message is 858 * followed by any other message, an error is returned 859 * indicating that this sequence is not supported. 860 */ 861 for (count = 0; (count < num - 1 && hold_quirk); count++) { 862 if (msgs[count].flags & I2C_M_RD) { 863 dev_warn(adap->dev.parent, 864 "Can't do repeated start after a receive message\n"); 865 ret = -EOPNOTSUPP; 866 goto out; 867 } 868 } 869 id->bus_hold_flag = 1; 870 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); 871 reg |= CDNS_I2C_CR_HOLD; 872 cdns_i2c_writereg(reg, CDNS_I2C_CR_OFFSET); 873 } else { 874 id->bus_hold_flag = 0; 875 } 876 877 /* Process the msg one by one */ 878 for (count = 0; count < num; count++, msgs++) { 879 if (count == (num - 1)) 880 id->bus_hold_flag = 0; 881 882 ret = cdns_i2c_process_msg(id, msgs, adap); 883 if (ret) 884 goto out; 885 886 /* Report the other error interrupts to application */ 887 if (id->err_status) { 888 cdns_i2c_master_reset(adap); 889 890 if (id->err_status & CDNS_I2C_IXR_NACK) { 891 ret = -ENXIO; 892 goto out; 893 } 894 ret = -EIO; 895 goto out; 896 } 897 } 898 899 ret = num; 900 901 out: 902 903 #if IS_ENABLED(CONFIG_I2C_SLAVE) 904 /* Switch i2c mode to slave */ 905 if (change_role) 906 cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id); 907 #endif 908 909 pm_runtime_mark_last_busy(id->dev); 910 pm_runtime_put_autosuspend(id->dev); 911 return ret; 912 } 913 914 /** 915 * cdns_i2c_func - Returns the supported features of the I2C driver 916 * @adap: pointer to the i2c adapter structure 917 * 918 * Return: 32 bit value, each bit corresponding to a feature 919 */ 920 static u32 cdns_i2c_func(struct i2c_adapter *adap) 921 { 922 u32 func = I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | 923 (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) | 924 I2C_FUNC_SMBUS_BLOCK_DATA; 925 926 #if IS_ENABLED(CONFIG_I2C_SLAVE) 927 func |= I2C_FUNC_SLAVE; 928 #endif 929 930 return func; 931 } 932 933 #if IS_ENABLED(CONFIG_I2C_SLAVE) 934 static int cdns_reg_slave(struct i2c_client *slave) 935 { 936 int ret; 937 struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c, 938 adap); 939 940 if (id->slave) 941 return -EBUSY; 942 943 if (slave->flags & I2C_CLIENT_TEN) 944 return -EAFNOSUPPORT; 945 946 ret = pm_runtime_resume_and_get(id->dev); 947 if (ret < 0) 948 return ret; 949 950 /* Store slave information */ 951 id->slave = slave; 952 953 /* Enable I2C slave */ 954 cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id); 955 956 return 0; 957 } 958 959 static int cdns_unreg_slave(struct i2c_client *slave) 960 { 961 struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c, 962 adap); 963 964 pm_runtime_put(id->dev); 965 966 /* Remove slave information */ 967 id->slave = NULL; 968 969 /* Enable I2C master */ 970 cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id); 971 972 return 0; 973 } 974 #endif 975 976 static const struct i2c_algorithm cdns_i2c_algo = { 977 .master_xfer = cdns_i2c_master_xfer, 978 .functionality = cdns_i2c_func, 979 #if IS_ENABLED(CONFIG_I2C_SLAVE) 980 .reg_slave = cdns_reg_slave, 981 .unreg_slave = cdns_unreg_slave, 982 #endif 983 }; 984 985 /** 986 * cdns_i2c_calc_divs - Calculate clock dividers 987 * @f: I2C clock frequency 988 * @input_clk: Input clock frequency 989 * @a: First divider (return value) 990 * @b: Second divider (return value) 991 * 992 * f is used as input and output variable. As input it is used as target I2C 993 * frequency. On function exit f holds the actually resulting I2C frequency. 994 * 995 * Return: 0 on success, negative errno otherwise. 996 */ 997 static int cdns_i2c_calc_divs(unsigned long *f, unsigned long input_clk, 998 unsigned int *a, unsigned int *b) 999 { 1000 unsigned long fscl = *f, best_fscl = *f, actual_fscl, temp; 1001 unsigned int div_a, div_b, calc_div_a = 0, calc_div_b = 0; 1002 unsigned int last_error, current_error; 1003 1004 /* calculate (divisor_a+1) x (divisor_b+1) */ 1005 temp = input_clk / (22 * fscl); 1006 1007 /* 1008 * If the calculated value is negative or 0, the fscl input is out of 1009 * range. Return error. 1010 */ 1011 if (!temp || (temp > (CDNS_I2C_DIVA_MAX * CDNS_I2C_DIVB_MAX))) 1012 return -EINVAL; 1013 1014 last_error = -1; 1015 for (div_a = 0; div_a < CDNS_I2C_DIVA_MAX; div_a++) { 1016 div_b = DIV_ROUND_UP(input_clk, 22 * fscl * (div_a + 1)); 1017 1018 if ((div_b < 1) || (div_b > CDNS_I2C_DIVB_MAX)) 1019 continue; 1020 div_b--; 1021 1022 actual_fscl = input_clk / (22 * (div_a + 1) * (div_b + 1)); 1023 1024 if (actual_fscl > fscl) 1025 continue; 1026 1027 current_error = ((actual_fscl > fscl) ? (actual_fscl - fscl) : 1028 (fscl - actual_fscl)); 1029 1030 if (last_error > current_error) { 1031 calc_div_a = div_a; 1032 calc_div_b = div_b; 1033 best_fscl = actual_fscl; 1034 last_error = current_error; 1035 } 1036 } 1037 1038 *a = calc_div_a; 1039 *b = calc_div_b; 1040 *f = best_fscl; 1041 1042 return 0; 1043 } 1044 1045 /** 1046 * cdns_i2c_setclk - This function sets the serial clock rate for the I2C device 1047 * @clk_in: I2C clock input frequency in Hz 1048 * @id: Pointer to the I2C device structure 1049 * 1050 * The device must be idle rather than busy transferring data before setting 1051 * these device options. 1052 * The data rate is set by values in the control register. 1053 * The formula for determining the correct register values is 1054 * Fscl = Fpclk/(22 x (divisor_a+1) x (divisor_b+1)) 1055 * See the hardware data sheet for a full explanation of setting the serial 1056 * clock rate. The clock can not be faster than the input clock divide by 22. 1057 * The two most common clock rates are 100KHz and 400KHz. 1058 * 1059 * Return: 0 on success, negative error otherwise 1060 */ 1061 static int cdns_i2c_setclk(unsigned long clk_in, struct cdns_i2c *id) 1062 { 1063 unsigned int div_a, div_b; 1064 unsigned int ctrl_reg; 1065 int ret = 0; 1066 unsigned long fscl = id->i2c_clk; 1067 1068 ret = cdns_i2c_calc_divs(&fscl, clk_in, &div_a, &div_b); 1069 if (ret) 1070 return ret; 1071 1072 ctrl_reg = id->ctrl_reg; 1073 ctrl_reg &= ~(CDNS_I2C_CR_DIVA_MASK | CDNS_I2C_CR_DIVB_MASK); 1074 ctrl_reg |= ((div_a << CDNS_I2C_CR_DIVA_SHIFT) | 1075 (div_b << CDNS_I2C_CR_DIVB_SHIFT)); 1076 id->ctrl_reg = ctrl_reg; 1077 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); 1078 #if IS_ENABLED(CONFIG_I2C_SLAVE) 1079 id->ctrl_reg_diva_divb = ctrl_reg & (CDNS_I2C_CR_DIVA_MASK | 1080 CDNS_I2C_CR_DIVB_MASK); 1081 #endif 1082 return 0; 1083 } 1084 1085 /** 1086 * cdns_i2c_clk_notifier_cb - Clock rate change callback 1087 * @nb: Pointer to notifier block 1088 * @event: Notification reason 1089 * @data: Pointer to notification data object 1090 * 1091 * This function is called when the cdns_i2c input clock frequency changes. 1092 * The callback checks whether a valid bus frequency can be generated after the 1093 * change. If so, the change is acknowledged, otherwise the change is aborted. 1094 * New dividers are written to the HW in the pre- or post change notification 1095 * depending on the scaling direction. 1096 * 1097 * Return: NOTIFY_STOP if the rate change should be aborted, NOTIFY_OK 1098 * to acknowledge the change, NOTIFY_DONE if the notification is 1099 * considered irrelevant. 1100 */ 1101 static int cdns_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long 1102 event, void *data) 1103 { 1104 struct clk_notifier_data *ndata = data; 1105 struct cdns_i2c *id = to_cdns_i2c(nb); 1106 1107 if (pm_runtime_suspended(id->dev)) 1108 return NOTIFY_OK; 1109 1110 switch (event) { 1111 case PRE_RATE_CHANGE: 1112 { 1113 unsigned long input_clk = ndata->new_rate; 1114 unsigned long fscl = id->i2c_clk; 1115 unsigned int div_a, div_b; 1116 int ret; 1117 1118 ret = cdns_i2c_calc_divs(&fscl, input_clk, &div_a, &div_b); 1119 if (ret) { 1120 dev_warn(id->adap.dev.parent, 1121 "clock rate change rejected\n"); 1122 return NOTIFY_STOP; 1123 } 1124 1125 /* scale up */ 1126 if (ndata->new_rate > ndata->old_rate) 1127 cdns_i2c_setclk(ndata->new_rate, id); 1128 1129 return NOTIFY_OK; 1130 } 1131 case POST_RATE_CHANGE: 1132 id->input_clk = ndata->new_rate; 1133 /* scale down */ 1134 if (ndata->new_rate < ndata->old_rate) 1135 cdns_i2c_setclk(ndata->new_rate, id); 1136 return NOTIFY_OK; 1137 case ABORT_RATE_CHANGE: 1138 /* scale up */ 1139 if (ndata->new_rate > ndata->old_rate) 1140 cdns_i2c_setclk(ndata->old_rate, id); 1141 return NOTIFY_OK; 1142 default: 1143 return NOTIFY_DONE; 1144 } 1145 } 1146 1147 /** 1148 * cdns_i2c_runtime_suspend - Runtime suspend method for the driver 1149 * @dev: Address of the platform_device structure 1150 * 1151 * Put the driver into low power mode. 1152 * 1153 * Return: 0 always 1154 */ 1155 static int __maybe_unused cdns_i2c_runtime_suspend(struct device *dev) 1156 { 1157 struct cdns_i2c *xi2c = dev_get_drvdata(dev); 1158 1159 clk_disable(xi2c->clk); 1160 1161 return 0; 1162 } 1163 1164 /** 1165 * cdns_i2c_init - Controller initialisation 1166 * @id: Device private data structure 1167 * 1168 * Initialise the i2c controller. 1169 * 1170 */ 1171 static void cdns_i2c_init(struct cdns_i2c *id) 1172 { 1173 cdns_i2c_writereg(id->ctrl_reg, CDNS_I2C_CR_OFFSET); 1174 /* 1175 * Cadence I2C controller has a bug wherein it generates 1176 * invalid read transaction after HW timeout in master receiver mode. 1177 * HW timeout is not used by this driver and the interrupt is disabled. 1178 * But the feature itself cannot be disabled. Hence maximum value 1179 * is written to this register to reduce the chances of error. 1180 */ 1181 cdns_i2c_writereg(CDNS_I2C_TIMEOUT_MAX, CDNS_I2C_TIME_OUT_OFFSET); 1182 } 1183 1184 /** 1185 * cdns_i2c_runtime_resume - Runtime resume 1186 * @dev: Address of the platform_device structure 1187 * 1188 * Runtime resume callback. 1189 * 1190 * Return: 0 on success and error value on error 1191 */ 1192 static int __maybe_unused cdns_i2c_runtime_resume(struct device *dev) 1193 { 1194 struct cdns_i2c *xi2c = dev_get_drvdata(dev); 1195 int ret; 1196 1197 ret = clk_enable(xi2c->clk); 1198 if (ret) { 1199 dev_err(dev, "Cannot enable clock.\n"); 1200 return ret; 1201 } 1202 cdns_i2c_init(xi2c); 1203 1204 return 0; 1205 } 1206 1207 static const struct dev_pm_ops cdns_i2c_dev_pm_ops = { 1208 SET_RUNTIME_PM_OPS(cdns_i2c_runtime_suspend, 1209 cdns_i2c_runtime_resume, NULL) 1210 }; 1211 1212 static const struct cdns_platform_data r1p10_i2c_def = { 1213 .quirks = CDNS_I2C_BROKEN_HOLD_BIT, 1214 }; 1215 1216 static const struct of_device_id cdns_i2c_of_match[] = { 1217 { .compatible = "cdns,i2c-r1p10", .data = &r1p10_i2c_def }, 1218 { .compatible = "cdns,i2c-r1p14",}, 1219 { /* end of table */ } 1220 }; 1221 MODULE_DEVICE_TABLE(of, cdns_i2c_of_match); 1222 1223 /** 1224 * cdns_i2c_probe - Platform registration call 1225 * @pdev: Handle to the platform device structure 1226 * 1227 * This function does all the memory allocation and registration for the i2c 1228 * device. User can modify the address mode to 10 bit address mode using the 1229 * ioctl call with option I2C_TENBIT. 1230 * 1231 * Return: 0 on success, negative error otherwise 1232 */ 1233 static int cdns_i2c_probe(struct platform_device *pdev) 1234 { 1235 struct resource *r_mem; 1236 struct cdns_i2c *id; 1237 int ret; 1238 const struct of_device_id *match; 1239 1240 id = devm_kzalloc(&pdev->dev, sizeof(*id), GFP_KERNEL); 1241 if (!id) 1242 return -ENOMEM; 1243 1244 id->dev = &pdev->dev; 1245 platform_set_drvdata(pdev, id); 1246 1247 match = of_match_node(cdns_i2c_of_match, pdev->dev.of_node); 1248 if (match && match->data) { 1249 const struct cdns_platform_data *data = match->data; 1250 id->quirks = data->quirks; 1251 } 1252 1253 id->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r_mem); 1254 if (IS_ERR(id->membase)) 1255 return PTR_ERR(id->membase); 1256 1257 ret = platform_get_irq(pdev, 0); 1258 if (ret < 0) 1259 return ret; 1260 id->irq = ret; 1261 1262 id->adap.owner = THIS_MODULE; 1263 id->adap.dev.of_node = pdev->dev.of_node; 1264 id->adap.algo = &cdns_i2c_algo; 1265 id->adap.timeout = CDNS_I2C_TIMEOUT; 1266 id->adap.retries = 3; /* Default retry value. */ 1267 id->adap.algo_data = id; 1268 id->adap.dev.parent = &pdev->dev; 1269 init_completion(&id->xfer_done); 1270 snprintf(id->adap.name, sizeof(id->adap.name), 1271 "Cadence I2C at %08lx", (unsigned long)r_mem->start); 1272 1273 id->clk = devm_clk_get(&pdev->dev, NULL); 1274 if (IS_ERR(id->clk)) 1275 return dev_err_probe(&pdev->dev, PTR_ERR(id->clk), 1276 "input clock not found.\n"); 1277 1278 ret = clk_prepare_enable(id->clk); 1279 if (ret) 1280 dev_err(&pdev->dev, "Unable to enable clock.\n"); 1281 1282 pm_runtime_set_autosuspend_delay(id->dev, CNDS_I2C_PM_TIMEOUT); 1283 pm_runtime_use_autosuspend(id->dev); 1284 pm_runtime_set_active(id->dev); 1285 pm_runtime_enable(id->dev); 1286 1287 id->clk_rate_change_nb.notifier_call = cdns_i2c_clk_notifier_cb; 1288 if (clk_notifier_register(id->clk, &id->clk_rate_change_nb)) 1289 dev_warn(&pdev->dev, "Unable to register clock notifier.\n"); 1290 id->input_clk = clk_get_rate(id->clk); 1291 1292 ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency", 1293 &id->i2c_clk); 1294 if (ret || (id->i2c_clk > I2C_MAX_FAST_MODE_FREQ)) 1295 id->i2c_clk = I2C_MAX_STANDARD_MODE_FREQ; 1296 1297 #if IS_ENABLED(CONFIG_I2C_SLAVE) 1298 /* Set initial mode to master */ 1299 id->dev_mode = CDNS_I2C_MODE_MASTER; 1300 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; 1301 #endif 1302 id->ctrl_reg = CDNS_I2C_CR_ACK_EN | CDNS_I2C_CR_NEA | CDNS_I2C_CR_MS; 1303 1304 ret = cdns_i2c_setclk(id->input_clk, id); 1305 if (ret) { 1306 dev_err(&pdev->dev, "invalid SCL clock: %u Hz\n", id->i2c_clk); 1307 ret = -EINVAL; 1308 goto err_clk_dis; 1309 } 1310 1311 ret = devm_request_irq(&pdev->dev, id->irq, cdns_i2c_isr, 0, 1312 DRIVER_NAME, id); 1313 if (ret) { 1314 dev_err(&pdev->dev, "cannot get irq %d\n", id->irq); 1315 goto err_clk_dis; 1316 } 1317 cdns_i2c_init(id); 1318 1319 ret = i2c_add_adapter(&id->adap); 1320 if (ret < 0) 1321 goto err_clk_dis; 1322 1323 dev_info(&pdev->dev, "%u kHz mmio %08lx irq %d\n", 1324 id->i2c_clk / 1000, (unsigned long)r_mem->start, id->irq); 1325 1326 return 0; 1327 1328 err_clk_dis: 1329 clk_notifier_unregister(id->clk, &id->clk_rate_change_nb); 1330 clk_disable_unprepare(id->clk); 1331 pm_runtime_disable(&pdev->dev); 1332 pm_runtime_set_suspended(&pdev->dev); 1333 return ret; 1334 } 1335 1336 /** 1337 * cdns_i2c_remove - Unregister the device after releasing the resources 1338 * @pdev: Handle to the platform device structure 1339 * 1340 * This function frees all the resources allocated to the device. 1341 * 1342 * Return: 0 always 1343 */ 1344 static int cdns_i2c_remove(struct platform_device *pdev) 1345 { 1346 struct cdns_i2c *id = platform_get_drvdata(pdev); 1347 1348 pm_runtime_disable(&pdev->dev); 1349 pm_runtime_set_suspended(&pdev->dev); 1350 pm_runtime_dont_use_autosuspend(&pdev->dev); 1351 1352 i2c_del_adapter(&id->adap); 1353 clk_notifier_unregister(id->clk, &id->clk_rate_change_nb); 1354 clk_disable_unprepare(id->clk); 1355 1356 return 0; 1357 } 1358 1359 static struct platform_driver cdns_i2c_drv = { 1360 .driver = { 1361 .name = DRIVER_NAME, 1362 .of_match_table = cdns_i2c_of_match, 1363 .pm = &cdns_i2c_dev_pm_ops, 1364 }, 1365 .probe = cdns_i2c_probe, 1366 .remove = cdns_i2c_remove, 1367 }; 1368 1369 module_platform_driver(cdns_i2c_drv); 1370 1371 MODULE_AUTHOR("Xilinx Inc."); 1372 MODULE_DESCRIPTION("Cadence I2C bus driver"); 1373 MODULE_LICENSE("GPL"); 1374