1 /* 2 * Copyright (C) 2013 STMicroelectronics 3 * 4 * I2C master mode controller driver, used in STMicroelectronics devices. 5 * 6 * Author: Maxime Coquelin <maxime.coquelin@st.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2, as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/module.h> 14 #include <linux/platform_device.h> 15 #include <linux/i2c.h> 16 #include <linux/clk.h> 17 #include <linux/io.h> 18 #include <linux/delay.h> 19 #include <linux/interrupt.h> 20 #include <linux/err.h> 21 #include <linux/of.h> 22 #include <linux/of_address.h> 23 #include <linux/of_irq.h> 24 25 /* SSC registers */ 26 #define SSC_BRG 0x000 27 #define SSC_TBUF 0x004 28 #define SSC_RBUF 0x008 29 #define SSC_CTL 0x00C 30 #define SSC_IEN 0x010 31 #define SSC_STA 0x014 32 #define SSC_I2C 0x018 33 #define SSC_SLAD 0x01C 34 #define SSC_REP_START_HOLD 0x020 35 #define SSC_START_HOLD 0x024 36 #define SSC_REP_START_SETUP 0x028 37 #define SSC_DATA_SETUP 0x02C 38 #define SSC_STOP_SETUP 0x030 39 #define SSC_BUS_FREE 0x034 40 #define SSC_TX_FSTAT 0x038 41 #define SSC_RX_FSTAT 0x03C 42 #define SSC_PRE_SCALER_BRG 0x040 43 #define SSC_CLR 0x080 44 #define SSC_NOISE_SUPP_WIDTH 0x100 45 #define SSC_PRSCALER 0x104 46 #define SSC_NOISE_SUPP_WIDTH_DATAOUT 0x108 47 #define SSC_PRSCALER_DATAOUT 0x10c 48 49 /* SSC Control */ 50 #define SSC_CTL_DATA_WIDTH_9 0x8 51 #define SSC_CTL_DATA_WIDTH_MSK 0xf 52 #define SSC_CTL_BM 0xf 53 #define SSC_CTL_HB BIT(4) 54 #define SSC_CTL_PH BIT(5) 55 #define SSC_CTL_PO BIT(6) 56 #define SSC_CTL_SR BIT(7) 57 #define SSC_CTL_MS BIT(8) 58 #define SSC_CTL_EN BIT(9) 59 #define SSC_CTL_LPB BIT(10) 60 #define SSC_CTL_EN_TX_FIFO BIT(11) 61 #define SSC_CTL_EN_RX_FIFO BIT(12) 62 #define SSC_CTL_EN_CLST_RX BIT(13) 63 64 /* SSC Interrupt Enable */ 65 #define SSC_IEN_RIEN BIT(0) 66 #define SSC_IEN_TIEN BIT(1) 67 #define SSC_IEN_TEEN BIT(2) 68 #define SSC_IEN_REEN BIT(3) 69 #define SSC_IEN_PEEN BIT(4) 70 #define SSC_IEN_AASEN BIT(6) 71 #define SSC_IEN_STOPEN BIT(7) 72 #define SSC_IEN_ARBLEN BIT(8) 73 #define SSC_IEN_NACKEN BIT(10) 74 #define SSC_IEN_REPSTRTEN BIT(11) 75 #define SSC_IEN_TX_FIFO_HALF BIT(12) 76 #define SSC_IEN_RX_FIFO_HALF_FULL BIT(14) 77 78 /* SSC Status */ 79 #define SSC_STA_RIR BIT(0) 80 #define SSC_STA_TIR BIT(1) 81 #define SSC_STA_TE BIT(2) 82 #define SSC_STA_RE BIT(3) 83 #define SSC_STA_PE BIT(4) 84 #define SSC_STA_CLST BIT(5) 85 #define SSC_STA_AAS BIT(6) 86 #define SSC_STA_STOP BIT(7) 87 #define SSC_STA_ARBL BIT(8) 88 #define SSC_STA_BUSY BIT(9) 89 #define SSC_STA_NACK BIT(10) 90 #define SSC_STA_REPSTRT BIT(11) 91 #define SSC_STA_TX_FIFO_HALF BIT(12) 92 #define SSC_STA_TX_FIFO_FULL BIT(13) 93 #define SSC_STA_RX_FIFO_HALF BIT(14) 94 95 /* SSC I2C Control */ 96 #define SSC_I2C_I2CM BIT(0) 97 #define SSC_I2C_STRTG BIT(1) 98 #define SSC_I2C_STOPG BIT(2) 99 #define SSC_I2C_ACKG BIT(3) 100 #define SSC_I2C_AD10 BIT(4) 101 #define SSC_I2C_TXENB BIT(5) 102 #define SSC_I2C_REPSTRTG BIT(11) 103 #define SSC_I2C_SLAVE_DISABLE BIT(12) 104 105 /* SSC Tx FIFO Status */ 106 #define SSC_TX_FSTAT_STATUS 0x07 107 108 /* SSC Rx FIFO Status */ 109 #define SSC_RX_FSTAT_STATUS 0x07 110 111 /* SSC Clear bit operation */ 112 #define SSC_CLR_SSCAAS BIT(6) 113 #define SSC_CLR_SSCSTOP BIT(7) 114 #define SSC_CLR_SSCARBL BIT(8) 115 #define SSC_CLR_NACK BIT(10) 116 #define SSC_CLR_REPSTRT BIT(11) 117 118 /* SSC Clock Prescaler */ 119 #define SSC_PRSC_VALUE 0x0f 120 121 122 #define SSC_TXFIFO_SIZE 0x8 123 #define SSC_RXFIFO_SIZE 0x8 124 125 enum st_i2c_mode { 126 I2C_MODE_STANDARD, 127 I2C_MODE_FAST, 128 I2C_MODE_END, 129 }; 130 131 /** 132 * struct st_i2c_timings - per-Mode tuning parameters 133 * @rate: I2C bus rate 134 * @rep_start_hold: I2C repeated start hold time requirement 135 * @rep_start_setup: I2C repeated start set up time requirement 136 * @start_hold: I2C start hold time requirement 137 * @data_setup_time: I2C data set up time requirement 138 * @stop_setup_time: I2C stop set up time requirement 139 * @bus_free_time: I2C bus free time requirement 140 * @sda_pulse_min_limit: I2C SDA pulse mini width limit 141 */ 142 struct st_i2c_timings { 143 u32 rate; 144 u32 rep_start_hold; 145 u32 rep_start_setup; 146 u32 start_hold; 147 u32 data_setup_time; 148 u32 stop_setup_time; 149 u32 bus_free_time; 150 u32 sda_pulse_min_limit; 151 }; 152 153 /** 154 * struct st_i2c_client - client specific data 155 * @addr: 8-bit slave addr, including r/w bit 156 * @count: number of bytes to be transfered 157 * @xfered: number of bytes already transferred 158 * @buf: data buffer 159 * @result: result of the transfer 160 * @stop: last I2C msg to be sent, i.e. STOP to be generated 161 */ 162 struct st_i2c_client { 163 u8 addr; 164 u32 count; 165 u32 xfered; 166 u8 *buf; 167 int result; 168 bool stop; 169 }; 170 171 /** 172 * struct st_i2c_dev - private data of the controller 173 * @adap: I2C adapter for this controller 174 * @dev: device for this controller 175 * @base: virtual memory area 176 * @complete: completion of I2C message 177 * @irq: interrupt line for th controller 178 * @clk: hw ssc block clock 179 * @mode: I2C mode of the controller. Standard or Fast only supported 180 * @scl_min_width_us: SCL line minimum pulse width in us 181 * @sda_min_width_us: SDA line minimum pulse width in us 182 * @client: I2C transfert information 183 * @busy: I2C transfer on-going 184 */ 185 struct st_i2c_dev { 186 struct i2c_adapter adap; 187 struct device *dev; 188 void __iomem *base; 189 struct completion complete; 190 int irq; 191 struct clk *clk; 192 int mode; 193 u32 scl_min_width_us; 194 u32 sda_min_width_us; 195 struct st_i2c_client client; 196 bool busy; 197 }; 198 199 static inline void st_i2c_set_bits(void __iomem *reg, u32 mask) 200 { 201 writel_relaxed(readl_relaxed(reg) | mask, reg); 202 } 203 204 static inline void st_i2c_clr_bits(void __iomem *reg, u32 mask) 205 { 206 writel_relaxed(readl_relaxed(reg) & ~mask, reg); 207 } 208 209 /* 210 * From I2C Specifications v0.5. 211 * 212 * All the values below have +10% margin added to be 213 * compatible with some out-of-spec devices, 214 * like HDMI link of the Toshiba 19AV600 TV. 215 */ 216 static struct st_i2c_timings i2c_timings[] = { 217 [I2C_MODE_STANDARD] = { 218 .rate = 100000, 219 .rep_start_hold = 4400, 220 .rep_start_setup = 5170, 221 .start_hold = 4400, 222 .data_setup_time = 275, 223 .stop_setup_time = 4400, 224 .bus_free_time = 5170, 225 }, 226 [I2C_MODE_FAST] = { 227 .rate = 400000, 228 .rep_start_hold = 660, 229 .rep_start_setup = 660, 230 .start_hold = 660, 231 .data_setup_time = 110, 232 .stop_setup_time = 660, 233 .bus_free_time = 1430, 234 }, 235 }; 236 237 static void st_i2c_flush_rx_fifo(struct st_i2c_dev *i2c_dev) 238 { 239 int count, i; 240 241 /* 242 * Counter only counts up to 7 but fifo size is 8... 243 * When fifo is full, counter is 0 and RIR bit of status register is 244 * set 245 */ 246 if (readl_relaxed(i2c_dev->base + SSC_STA) & SSC_STA_RIR) 247 count = SSC_RXFIFO_SIZE; 248 else 249 count = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT) & 250 SSC_RX_FSTAT_STATUS; 251 252 for (i = 0; i < count; i++) 253 readl_relaxed(i2c_dev->base + SSC_RBUF); 254 } 255 256 static void st_i2c_soft_reset(struct st_i2c_dev *i2c_dev) 257 { 258 /* 259 * FIFO needs to be emptied before reseting the IP, 260 * else the controller raises a BUSY error. 261 */ 262 st_i2c_flush_rx_fifo(i2c_dev); 263 264 st_i2c_set_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR); 265 st_i2c_clr_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR); 266 } 267 268 /** 269 * st_i2c_hw_config() - Prepare SSC block, calculate and apply tuning timings 270 * @i2c_dev: Controller's private data 271 */ 272 static void st_i2c_hw_config(struct st_i2c_dev *i2c_dev) 273 { 274 unsigned long rate; 275 u32 val, ns_per_clk; 276 struct st_i2c_timings *t = &i2c_timings[i2c_dev->mode]; 277 278 st_i2c_soft_reset(i2c_dev); 279 280 val = SSC_CLR_REPSTRT | SSC_CLR_NACK | SSC_CLR_SSCARBL | 281 SSC_CLR_SSCAAS | SSC_CLR_SSCSTOP; 282 writel_relaxed(val, i2c_dev->base + SSC_CLR); 283 284 /* SSC Control register setup */ 285 val = SSC_CTL_PO | SSC_CTL_PH | SSC_CTL_HB | SSC_CTL_DATA_WIDTH_9; 286 writel_relaxed(val, i2c_dev->base + SSC_CTL); 287 288 rate = clk_get_rate(i2c_dev->clk); 289 ns_per_clk = 1000000000 / rate; 290 291 /* Baudrate */ 292 val = rate / (2 * t->rate); 293 writel_relaxed(val, i2c_dev->base + SSC_BRG); 294 295 /* Pre-scaler baudrate */ 296 writel_relaxed(1, i2c_dev->base + SSC_PRE_SCALER_BRG); 297 298 /* Enable I2C mode */ 299 writel_relaxed(SSC_I2C_I2CM, i2c_dev->base + SSC_I2C); 300 301 /* Repeated start hold time */ 302 val = t->rep_start_hold / ns_per_clk; 303 writel_relaxed(val, i2c_dev->base + SSC_REP_START_HOLD); 304 305 /* Repeated start set up time */ 306 val = t->rep_start_setup / ns_per_clk; 307 writel_relaxed(val, i2c_dev->base + SSC_REP_START_SETUP); 308 309 /* Start hold time */ 310 val = t->start_hold / ns_per_clk; 311 writel_relaxed(val, i2c_dev->base + SSC_START_HOLD); 312 313 /* Data set up time */ 314 val = t->data_setup_time / ns_per_clk; 315 writel_relaxed(val, i2c_dev->base + SSC_DATA_SETUP); 316 317 /* Stop set up time */ 318 val = t->stop_setup_time / ns_per_clk; 319 writel_relaxed(val, i2c_dev->base + SSC_STOP_SETUP); 320 321 /* Bus free time */ 322 val = t->bus_free_time / ns_per_clk; 323 writel_relaxed(val, i2c_dev->base + SSC_BUS_FREE); 324 325 /* Prescalers set up */ 326 val = rate / 10000000; 327 writel_relaxed(val, i2c_dev->base + SSC_PRSCALER); 328 writel_relaxed(val, i2c_dev->base + SSC_PRSCALER_DATAOUT); 329 330 /* Noise suppression witdh */ 331 val = i2c_dev->scl_min_width_us * rate / 100000000; 332 writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH); 333 334 /* Noise suppression max output data delay width */ 335 val = i2c_dev->sda_min_width_us * rate / 100000000; 336 writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT); 337 } 338 339 static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev) 340 { 341 u32 sta; 342 int i; 343 344 for (i = 0; i < 10; i++) { 345 sta = readl_relaxed(i2c_dev->base + SSC_STA); 346 if (!(sta & SSC_STA_BUSY)) 347 return 0; 348 349 usleep_range(2000, 4000); 350 } 351 352 dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta); 353 354 return -EBUSY; 355 } 356 357 /** 358 * st_i2c_write_tx_fifo() - Write a byte in the Tx FIFO 359 * @i2c_dev: Controller's private data 360 * @byte: Data to write in the Tx FIFO 361 */ 362 static inline void st_i2c_write_tx_fifo(struct st_i2c_dev *i2c_dev, u8 byte) 363 { 364 u16 tbuf = byte << 1; 365 366 writel_relaxed(tbuf | 1, i2c_dev->base + SSC_TBUF); 367 } 368 369 /** 370 * st_i2c_wr_fill_tx_fifo() - Fill the Tx FIFO in write mode 371 * @i2c_dev: Controller's private data 372 * 373 * This functions fills the Tx FIFO with I2C transfert buffer when 374 * in write mode. 375 */ 376 static void st_i2c_wr_fill_tx_fifo(struct st_i2c_dev *i2c_dev) 377 { 378 struct st_i2c_client *c = &i2c_dev->client; 379 u32 tx_fstat, sta; 380 int i; 381 382 sta = readl_relaxed(i2c_dev->base + SSC_STA); 383 if (sta & SSC_STA_TX_FIFO_FULL) 384 return; 385 386 tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT); 387 tx_fstat &= SSC_TX_FSTAT_STATUS; 388 389 if (c->count < (SSC_TXFIFO_SIZE - tx_fstat)) 390 i = c->count; 391 else 392 i = SSC_TXFIFO_SIZE - tx_fstat; 393 394 for (; i > 0; i--, c->count--, c->buf++) 395 st_i2c_write_tx_fifo(i2c_dev, *c->buf); 396 } 397 398 /** 399 * st_i2c_rd_fill_tx_fifo() - Fill the Tx FIFO in read mode 400 * @i2c_dev: Controller's private data 401 * 402 * This functions fills the Tx FIFO with fixed pattern when 403 * in read mode to trigger clock. 404 */ 405 static void st_i2c_rd_fill_tx_fifo(struct st_i2c_dev *i2c_dev, int max) 406 { 407 struct st_i2c_client *c = &i2c_dev->client; 408 u32 tx_fstat, sta; 409 int i; 410 411 sta = readl_relaxed(i2c_dev->base + SSC_STA); 412 if (sta & SSC_STA_TX_FIFO_FULL) 413 return; 414 415 tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT); 416 tx_fstat &= SSC_TX_FSTAT_STATUS; 417 418 if (max < (SSC_TXFIFO_SIZE - tx_fstat)) 419 i = max; 420 else 421 i = SSC_TXFIFO_SIZE - tx_fstat; 422 423 for (; i > 0; i--, c->xfered++) 424 st_i2c_write_tx_fifo(i2c_dev, 0xff); 425 } 426 427 static void st_i2c_read_rx_fifo(struct st_i2c_dev *i2c_dev) 428 { 429 struct st_i2c_client *c = &i2c_dev->client; 430 u32 i, sta; 431 u16 rbuf; 432 433 sta = readl_relaxed(i2c_dev->base + SSC_STA); 434 if (sta & SSC_STA_RIR) { 435 i = SSC_RXFIFO_SIZE; 436 } else { 437 i = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT); 438 i &= SSC_RX_FSTAT_STATUS; 439 } 440 441 for (; (i > 0) && (c->count > 0); i--, c->count--) { 442 rbuf = readl_relaxed(i2c_dev->base + SSC_RBUF) >> 1; 443 *c->buf++ = (u8)rbuf & 0xff; 444 } 445 446 if (i) { 447 dev_err(i2c_dev->dev, "Unexpected %d bytes in rx fifo\n", i); 448 st_i2c_flush_rx_fifo(i2c_dev); 449 } 450 } 451 452 /** 453 * st_i2c_terminate_xfer() - Send either STOP or REPSTART condition 454 * @i2c_dev: Controller's private data 455 */ 456 static void st_i2c_terminate_xfer(struct st_i2c_dev *i2c_dev) 457 { 458 struct st_i2c_client *c = &i2c_dev->client; 459 460 st_i2c_clr_bits(i2c_dev->base + SSC_IEN, SSC_IEN_TEEN); 461 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG); 462 463 if (c->stop) { 464 st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_STOPEN); 465 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); 466 } else { 467 st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_REPSTRTEN); 468 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_REPSTRTG); 469 } 470 } 471 472 /** 473 * st_i2c_handle_write() - Handle FIFO empty interrupt in case of write 474 * @i2c_dev: Controller's private data 475 */ 476 static void st_i2c_handle_write(struct st_i2c_dev *i2c_dev) 477 { 478 struct st_i2c_client *c = &i2c_dev->client; 479 480 st_i2c_flush_rx_fifo(i2c_dev); 481 482 if (!c->count) 483 /* End of xfer, send stop or repstart */ 484 st_i2c_terminate_xfer(i2c_dev); 485 else 486 st_i2c_wr_fill_tx_fifo(i2c_dev); 487 } 488 489 /** 490 * st_i2c_handle_write() - Handle FIFO enmpty interrupt in case of read 491 * @i2c_dev: Controller's private data 492 */ 493 static void st_i2c_handle_read(struct st_i2c_dev *i2c_dev) 494 { 495 struct st_i2c_client *c = &i2c_dev->client; 496 u32 ien; 497 498 /* Trash the address read back */ 499 if (!c->xfered) { 500 readl_relaxed(i2c_dev->base + SSC_RBUF); 501 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_TXENB); 502 } else { 503 st_i2c_read_rx_fifo(i2c_dev); 504 } 505 506 if (!c->count) { 507 /* End of xfer, send stop or repstart */ 508 st_i2c_terminate_xfer(i2c_dev); 509 } else if (c->count == 1) { 510 /* Penultimate byte to xfer, disable ACK gen. */ 511 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_ACKG); 512 513 /* Last received byte is to be handled by NACK interrupt */ 514 ien = SSC_IEN_NACKEN | SSC_IEN_ARBLEN; 515 writel_relaxed(ien, i2c_dev->base + SSC_IEN); 516 517 st_i2c_rd_fill_tx_fifo(i2c_dev, c->count); 518 } else { 519 st_i2c_rd_fill_tx_fifo(i2c_dev, c->count - 1); 520 } 521 } 522 523 /** 524 * st_i2c_isr() - Interrupt routine 525 * @irq: interrupt number 526 * @data: Controller's private data 527 */ 528 static irqreturn_t st_i2c_isr_thread(int irq, void *data) 529 { 530 struct st_i2c_dev *i2c_dev = data; 531 struct st_i2c_client *c = &i2c_dev->client; 532 u32 sta, ien; 533 int it; 534 535 ien = readl_relaxed(i2c_dev->base + SSC_IEN); 536 sta = readl_relaxed(i2c_dev->base + SSC_STA); 537 538 /* Use __fls() to check error bits first */ 539 it = __fls(sta & ien); 540 if (it < 0) { 541 dev_dbg(i2c_dev->dev, "spurious it (sta=0x%04x, ien=0x%04x)\n", 542 sta, ien); 543 return IRQ_NONE; 544 } 545 546 switch (1 << it) { 547 case SSC_STA_TE: 548 if (c->addr & I2C_M_RD) 549 st_i2c_handle_read(i2c_dev); 550 else 551 st_i2c_handle_write(i2c_dev); 552 break; 553 554 case SSC_STA_STOP: 555 case SSC_STA_REPSTRT: 556 writel_relaxed(0, i2c_dev->base + SSC_IEN); 557 complete(&i2c_dev->complete); 558 break; 559 560 case SSC_STA_NACK: 561 writel_relaxed(SSC_CLR_NACK, i2c_dev->base + SSC_CLR); 562 563 /* Last received byte handled by NACK interrupt */ 564 if ((c->addr & I2C_M_RD) && (c->count == 1) && (c->xfered)) { 565 st_i2c_handle_read(i2c_dev); 566 break; 567 } 568 569 it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN; 570 writel_relaxed(it, i2c_dev->base + SSC_IEN); 571 572 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); 573 c->result = -EIO; 574 break; 575 576 case SSC_STA_ARBL: 577 writel_relaxed(SSC_CLR_SSCARBL, i2c_dev->base + SSC_CLR); 578 579 it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN; 580 writel_relaxed(it, i2c_dev->base + SSC_IEN); 581 582 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); 583 c->result = -EAGAIN; 584 break; 585 586 default: 587 dev_err(i2c_dev->dev, 588 "it %d unhandled (sta=0x%04x)\n", it, sta); 589 } 590 591 /* 592 * Read IEN register to ensure interrupt mask write is effective 593 * before re-enabling interrupt at GIC level, and thus avoid spurious 594 * interrupts. 595 */ 596 readl(i2c_dev->base + SSC_IEN); 597 598 return IRQ_HANDLED; 599 } 600 601 /** 602 * st_i2c_xfer_msg() - Transfer a single I2C message 603 * @i2c_dev: Controller's private data 604 * @msg: I2C message to transfer 605 * @is_first: first message of the sequence 606 * @is_last: last message of the sequence 607 */ 608 static int st_i2c_xfer_msg(struct st_i2c_dev *i2c_dev, struct i2c_msg *msg, 609 bool is_first, bool is_last) 610 { 611 struct st_i2c_client *c = &i2c_dev->client; 612 u32 ctl, i2c, it; 613 unsigned long timeout; 614 int ret; 615 616 c->addr = (u8)(msg->addr << 1); 617 c->addr |= (msg->flags & I2C_M_RD); 618 c->buf = msg->buf; 619 c->count = msg->len; 620 c->xfered = 0; 621 c->result = 0; 622 c->stop = is_last; 623 624 reinit_completion(&i2c_dev->complete); 625 626 ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO; 627 st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl); 628 629 i2c = SSC_I2C_TXENB; 630 if (c->addr & I2C_M_RD) 631 i2c |= SSC_I2C_ACKG; 632 st_i2c_set_bits(i2c_dev->base + SSC_I2C, i2c); 633 634 /* Write slave address */ 635 st_i2c_write_tx_fifo(i2c_dev, c->addr); 636 637 /* Pre-fill Tx fifo with data in case of write */ 638 if (!(c->addr & I2C_M_RD)) 639 st_i2c_wr_fill_tx_fifo(i2c_dev); 640 641 it = SSC_IEN_NACKEN | SSC_IEN_TEEN | SSC_IEN_ARBLEN; 642 writel_relaxed(it, i2c_dev->base + SSC_IEN); 643 644 if (is_first) { 645 ret = st_i2c_wait_free_bus(i2c_dev); 646 if (ret) 647 return ret; 648 649 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG); 650 } 651 652 timeout = wait_for_completion_timeout(&i2c_dev->complete, 653 i2c_dev->adap.timeout); 654 ret = c->result; 655 656 if (!timeout) { 657 dev_err(i2c_dev->dev, "Write to slave 0x%x timed out\n", 658 c->addr); 659 ret = -ETIMEDOUT; 660 } 661 662 i2c = SSC_I2C_STOPG | SSC_I2C_REPSTRTG; 663 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, i2c); 664 665 writel_relaxed(SSC_CLR_SSCSTOP | SSC_CLR_REPSTRT, 666 i2c_dev->base + SSC_CLR); 667 668 return ret; 669 } 670 671 /** 672 * st_i2c_xfer() - Transfer a single I2C message 673 * @i2c_adap: Adapter pointer to the controller 674 * @msgs: Pointer to data to be written. 675 * @num: Number of messages to be executed 676 */ 677 static int st_i2c_xfer(struct i2c_adapter *i2c_adap, 678 struct i2c_msg msgs[], int num) 679 { 680 struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap); 681 int ret, i; 682 683 i2c_dev->busy = true; 684 685 ret = clk_prepare_enable(i2c_dev->clk); 686 if (ret) { 687 dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n"); 688 return ret; 689 } 690 691 pinctrl_pm_select_default_state(i2c_dev->dev); 692 693 st_i2c_hw_config(i2c_dev); 694 695 for (i = 0; (i < num) && !ret; i++) 696 ret = st_i2c_xfer_msg(i2c_dev, &msgs[i], i == 0, i == num - 1); 697 698 pinctrl_pm_select_idle_state(i2c_dev->dev); 699 700 clk_disable_unprepare(i2c_dev->clk); 701 702 i2c_dev->busy = false; 703 704 return (ret < 0) ? ret : i; 705 } 706 707 #ifdef CONFIG_PM_SLEEP 708 static int st_i2c_suspend(struct device *dev) 709 { 710 struct platform_device *pdev = 711 container_of(dev, struct platform_device, dev); 712 struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev); 713 714 if (i2c_dev->busy) 715 return -EBUSY; 716 717 pinctrl_pm_select_sleep_state(dev); 718 719 return 0; 720 } 721 722 static int st_i2c_resume(struct device *dev) 723 { 724 pinctrl_pm_select_default_state(dev); 725 /* Go in idle state if available */ 726 pinctrl_pm_select_idle_state(dev); 727 728 return 0; 729 } 730 731 static SIMPLE_DEV_PM_OPS(st_i2c_pm, st_i2c_suspend, st_i2c_resume); 732 #define ST_I2C_PM (&st_i2c_pm) 733 #else 734 #define ST_I2C_PM NULL 735 #endif 736 737 static u32 st_i2c_func(struct i2c_adapter *adap) 738 { 739 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; 740 } 741 742 static struct i2c_algorithm st_i2c_algo = { 743 .master_xfer = st_i2c_xfer, 744 .functionality = st_i2c_func, 745 }; 746 747 static int st_i2c_of_get_deglitch(struct device_node *np, 748 struct st_i2c_dev *i2c_dev) 749 { 750 int ret; 751 752 ret = of_property_read_u32(np, "st,i2c-min-scl-pulse-width-us", 753 &i2c_dev->scl_min_width_us); 754 if ((ret == -ENODATA) || (ret == -EOVERFLOW)) { 755 dev_err(i2c_dev->dev, "st,i2c-min-scl-pulse-width-us invalid\n"); 756 return ret; 757 } 758 759 ret = of_property_read_u32(np, "st,i2c-min-sda-pulse-width-us", 760 &i2c_dev->sda_min_width_us); 761 if ((ret == -ENODATA) || (ret == -EOVERFLOW)) { 762 dev_err(i2c_dev->dev, "st,i2c-min-sda-pulse-width-us invalid\n"); 763 return ret; 764 } 765 766 return 0; 767 } 768 769 static int st_i2c_probe(struct platform_device *pdev) 770 { 771 struct device_node *np = pdev->dev.of_node; 772 struct st_i2c_dev *i2c_dev; 773 struct resource *res; 774 u32 clk_rate; 775 struct i2c_adapter *adap; 776 int ret; 777 778 i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); 779 if (!i2c_dev) 780 return -ENOMEM; 781 782 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 783 i2c_dev->base = devm_ioremap_resource(&pdev->dev, res); 784 if (IS_ERR(i2c_dev->base)) 785 return PTR_ERR(i2c_dev->base); 786 787 i2c_dev->irq = irq_of_parse_and_map(np, 0); 788 if (!i2c_dev->irq) { 789 dev_err(&pdev->dev, "IRQ missing or invalid\n"); 790 return -EINVAL; 791 } 792 793 i2c_dev->clk = of_clk_get_by_name(np, "ssc"); 794 if (IS_ERR(i2c_dev->clk)) { 795 dev_err(&pdev->dev, "Unable to request clock\n"); 796 return PTR_ERR(i2c_dev->clk); 797 } 798 799 i2c_dev->mode = I2C_MODE_STANDARD; 800 ret = of_property_read_u32(np, "clock-frequency", &clk_rate); 801 if ((!ret) && (clk_rate == 400000)) 802 i2c_dev->mode = I2C_MODE_FAST; 803 804 i2c_dev->dev = &pdev->dev; 805 806 ret = devm_request_threaded_irq(&pdev->dev, i2c_dev->irq, 807 NULL, st_i2c_isr_thread, 808 IRQF_ONESHOT, pdev->name, i2c_dev); 809 if (ret) { 810 dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq); 811 return ret; 812 } 813 814 pinctrl_pm_select_default_state(i2c_dev->dev); 815 /* In case idle state available, select it */ 816 pinctrl_pm_select_idle_state(i2c_dev->dev); 817 818 ret = st_i2c_of_get_deglitch(np, i2c_dev); 819 if (ret) 820 return ret; 821 822 adap = &i2c_dev->adap; 823 i2c_set_adapdata(adap, i2c_dev); 824 snprintf(adap->name, sizeof(adap->name), "ST I2C(0x%pa)", &res->start); 825 adap->owner = THIS_MODULE; 826 adap->timeout = 2 * HZ; 827 adap->retries = 0; 828 adap->algo = &st_i2c_algo; 829 adap->dev.parent = &pdev->dev; 830 adap->dev.of_node = pdev->dev.of_node; 831 832 init_completion(&i2c_dev->complete); 833 834 ret = i2c_add_adapter(adap); 835 if (ret) { 836 dev_err(&pdev->dev, "Failed to add adapter\n"); 837 return ret; 838 } 839 840 platform_set_drvdata(pdev, i2c_dev); 841 842 dev_info(i2c_dev->dev, "%s initialized\n", adap->name); 843 844 return 0; 845 } 846 847 static int st_i2c_remove(struct platform_device *pdev) 848 { 849 struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev); 850 851 i2c_del_adapter(&i2c_dev->adap); 852 853 return 0; 854 } 855 856 static const struct of_device_id st_i2c_match[] = { 857 { .compatible = "st,comms-ssc-i2c", }, 858 { .compatible = "st,comms-ssc4-i2c", }, 859 {}, 860 }; 861 MODULE_DEVICE_TABLE(of, st_i2c_match); 862 863 static struct platform_driver st_i2c_driver = { 864 .driver = { 865 .name = "st-i2c", 866 .of_match_table = st_i2c_match, 867 .pm = ST_I2C_PM, 868 }, 869 .probe = st_i2c_probe, 870 .remove = st_i2c_remove, 871 }; 872 873 module_platform_driver(st_i2c_driver); 874 875 MODULE_AUTHOR("Maxime Coquelin <maxime.coquelin@st.com>"); 876 MODULE_DESCRIPTION("STMicroelectronics I2C driver"); 877 MODULE_LICENSE("GPL v2"); 878