1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2013 STMicroelectronics 4 * 5 * I2C master mode controller driver, used in STMicroelectronics devices. 6 * 7 * Author: Maxime Coquelin <maxime.coquelin@st.com> 8 */ 9 10 #include <linux/clk.h> 11 #include <linux/delay.h> 12 #include <linux/err.h> 13 #include <linux/i2c.h> 14 #include <linux/interrupt.h> 15 #include <linux/io.h> 16 #include <linux/module.h> 17 #include <linux/of_address.h> 18 #include <linux/of_irq.h> 19 #include <linux/of.h> 20 #include <linux/pinctrl/consumer.h> 21 #include <linux/platform_device.h> 22 23 /* SSC registers */ 24 #define SSC_BRG 0x000 25 #define SSC_TBUF 0x004 26 #define SSC_RBUF 0x008 27 #define SSC_CTL 0x00C 28 #define SSC_IEN 0x010 29 #define SSC_STA 0x014 30 #define SSC_I2C 0x018 31 #define SSC_SLAD 0x01C 32 #define SSC_REP_START_HOLD 0x020 33 #define SSC_START_HOLD 0x024 34 #define SSC_REP_START_SETUP 0x028 35 #define SSC_DATA_SETUP 0x02C 36 #define SSC_STOP_SETUP 0x030 37 #define SSC_BUS_FREE 0x034 38 #define SSC_TX_FSTAT 0x038 39 #define SSC_RX_FSTAT 0x03C 40 #define SSC_PRE_SCALER_BRG 0x040 41 #define SSC_CLR 0x080 42 #define SSC_NOISE_SUPP_WIDTH 0x100 43 #define SSC_PRSCALER 0x104 44 #define SSC_NOISE_SUPP_WIDTH_DATAOUT 0x108 45 #define SSC_PRSCALER_DATAOUT 0x10c 46 47 /* SSC Control */ 48 #define SSC_CTL_DATA_WIDTH_9 0x8 49 #define SSC_CTL_DATA_WIDTH_MSK 0xf 50 #define SSC_CTL_BM 0xf 51 #define SSC_CTL_HB BIT(4) 52 #define SSC_CTL_PH BIT(5) 53 #define SSC_CTL_PO BIT(6) 54 #define SSC_CTL_SR BIT(7) 55 #define SSC_CTL_MS BIT(8) 56 #define SSC_CTL_EN BIT(9) 57 #define SSC_CTL_LPB BIT(10) 58 #define SSC_CTL_EN_TX_FIFO BIT(11) 59 #define SSC_CTL_EN_RX_FIFO BIT(12) 60 #define SSC_CTL_EN_CLST_RX BIT(13) 61 62 /* SSC Interrupt Enable */ 63 #define SSC_IEN_RIEN BIT(0) 64 #define SSC_IEN_TIEN BIT(1) 65 #define SSC_IEN_TEEN BIT(2) 66 #define SSC_IEN_REEN BIT(3) 67 #define SSC_IEN_PEEN BIT(4) 68 #define SSC_IEN_AASEN BIT(6) 69 #define SSC_IEN_STOPEN BIT(7) 70 #define SSC_IEN_ARBLEN BIT(8) 71 #define SSC_IEN_NACKEN BIT(10) 72 #define SSC_IEN_REPSTRTEN BIT(11) 73 #define SSC_IEN_TX_FIFO_HALF BIT(12) 74 #define SSC_IEN_RX_FIFO_HALF_FULL BIT(14) 75 76 /* SSC Status */ 77 #define SSC_STA_RIR BIT(0) 78 #define SSC_STA_TIR BIT(1) 79 #define SSC_STA_TE BIT(2) 80 #define SSC_STA_RE BIT(3) 81 #define SSC_STA_PE BIT(4) 82 #define SSC_STA_CLST BIT(5) 83 #define SSC_STA_AAS BIT(6) 84 #define SSC_STA_STOP BIT(7) 85 #define SSC_STA_ARBL BIT(8) 86 #define SSC_STA_BUSY BIT(9) 87 #define SSC_STA_NACK BIT(10) 88 #define SSC_STA_REPSTRT BIT(11) 89 #define SSC_STA_TX_FIFO_HALF BIT(12) 90 #define SSC_STA_TX_FIFO_FULL BIT(13) 91 #define SSC_STA_RX_FIFO_HALF BIT(14) 92 93 /* SSC I2C Control */ 94 #define SSC_I2C_I2CM BIT(0) 95 #define SSC_I2C_STRTG BIT(1) 96 #define SSC_I2C_STOPG BIT(2) 97 #define SSC_I2C_ACKG BIT(3) 98 #define SSC_I2C_AD10 BIT(4) 99 #define SSC_I2C_TXENB BIT(5) 100 #define SSC_I2C_REPSTRTG BIT(11) 101 #define SSC_I2C_SLAVE_DISABLE BIT(12) 102 103 /* SSC Tx FIFO Status */ 104 #define SSC_TX_FSTAT_STATUS 0x07 105 106 /* SSC Rx FIFO Status */ 107 #define SSC_RX_FSTAT_STATUS 0x07 108 109 /* SSC Clear bit operation */ 110 #define SSC_CLR_SSCAAS BIT(6) 111 #define SSC_CLR_SSCSTOP BIT(7) 112 #define SSC_CLR_SSCARBL BIT(8) 113 #define SSC_CLR_NACK BIT(10) 114 #define SSC_CLR_REPSTRT BIT(11) 115 116 /* SSC Clock Prescaler */ 117 #define SSC_PRSC_VALUE 0x0f 118 119 120 #define SSC_TXFIFO_SIZE 0x8 121 #define SSC_RXFIFO_SIZE 0x8 122 123 enum st_i2c_mode { 124 I2C_MODE_STANDARD, 125 I2C_MODE_FAST, 126 I2C_MODE_END, 127 }; 128 129 /** 130 * struct st_i2c_timings - per-Mode tuning parameters 131 * @rate: I2C bus rate 132 * @rep_start_hold: I2C repeated start hold time requirement 133 * @rep_start_setup: I2C repeated start set up time requirement 134 * @start_hold: I2C start hold time requirement 135 * @data_setup_time: I2C data set up time requirement 136 * @stop_setup_time: I2C stop set up time requirement 137 * @bus_free_time: I2C bus free time requirement 138 * @sda_pulse_min_limit: I2C SDA pulse mini width limit 139 */ 140 struct st_i2c_timings { 141 u32 rate; 142 u32 rep_start_hold; 143 u32 rep_start_setup; 144 u32 start_hold; 145 u32 data_setup_time; 146 u32 stop_setup_time; 147 u32 bus_free_time; 148 u32 sda_pulse_min_limit; 149 }; 150 151 /** 152 * struct st_i2c_client - client specific data 153 * @addr: 8-bit slave addr, including r/w bit 154 * @count: number of bytes to be transfered 155 * @xfered: number of bytes already transferred 156 * @buf: data buffer 157 * @result: result of the transfer 158 * @stop: last I2C msg to be sent, i.e. STOP to be generated 159 */ 160 struct st_i2c_client { 161 u8 addr; 162 u32 count; 163 u32 xfered; 164 u8 *buf; 165 int result; 166 bool stop; 167 }; 168 169 /** 170 * struct st_i2c_dev - private data of the controller 171 * @adap: I2C adapter for this controller 172 * @dev: device for this controller 173 * @base: virtual memory area 174 * @complete: completion of I2C message 175 * @irq: interrupt line for th controller 176 * @clk: hw ssc block clock 177 * @mode: I2C mode of the controller. Standard or Fast only supported 178 * @scl_min_width_us: SCL line minimum pulse width in us 179 * @sda_min_width_us: SDA line minimum pulse width in us 180 * @client: I2C transfert information 181 * @busy: I2C transfer on-going 182 */ 183 struct st_i2c_dev { 184 struct i2c_adapter adap; 185 struct device *dev; 186 void __iomem *base; 187 struct completion complete; 188 int irq; 189 struct clk *clk; 190 int mode; 191 u32 scl_min_width_us; 192 u32 sda_min_width_us; 193 struct st_i2c_client client; 194 bool busy; 195 }; 196 197 static inline void st_i2c_set_bits(void __iomem *reg, u32 mask) 198 { 199 writel_relaxed(readl_relaxed(reg) | mask, reg); 200 } 201 202 static inline void st_i2c_clr_bits(void __iomem *reg, u32 mask) 203 { 204 writel_relaxed(readl_relaxed(reg) & ~mask, reg); 205 } 206 207 /* 208 * From I2C Specifications v0.5. 209 * 210 * All the values below have +10% margin added to be 211 * compatible with some out-of-spec devices, 212 * like HDMI link of the Toshiba 19AV600 TV. 213 */ 214 static struct st_i2c_timings i2c_timings[] = { 215 [I2C_MODE_STANDARD] = { 216 .rate = I2C_MAX_STANDARD_MODE_FREQ, 217 .rep_start_hold = 4400, 218 .rep_start_setup = 5170, 219 .start_hold = 4400, 220 .data_setup_time = 275, 221 .stop_setup_time = 4400, 222 .bus_free_time = 5170, 223 }, 224 [I2C_MODE_FAST] = { 225 .rate = I2C_MAX_FAST_MODE_FREQ, 226 .rep_start_hold = 660, 227 .rep_start_setup = 660, 228 .start_hold = 660, 229 .data_setup_time = 110, 230 .stop_setup_time = 660, 231 .bus_free_time = 1430, 232 }, 233 }; 234 235 static void st_i2c_flush_rx_fifo(struct st_i2c_dev *i2c_dev) 236 { 237 int count, i; 238 239 /* 240 * Counter only counts up to 7 but fifo size is 8... 241 * When fifo is full, counter is 0 and RIR bit of status register is 242 * set 243 */ 244 if (readl_relaxed(i2c_dev->base + SSC_STA) & SSC_STA_RIR) 245 count = SSC_RXFIFO_SIZE; 246 else 247 count = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT) & 248 SSC_RX_FSTAT_STATUS; 249 250 for (i = 0; i < count; i++) 251 readl_relaxed(i2c_dev->base + SSC_RBUF); 252 } 253 254 static void st_i2c_soft_reset(struct st_i2c_dev *i2c_dev) 255 { 256 /* 257 * FIFO needs to be emptied before reseting the IP, 258 * else the controller raises a BUSY error. 259 */ 260 st_i2c_flush_rx_fifo(i2c_dev); 261 262 st_i2c_set_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR); 263 st_i2c_clr_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR); 264 } 265 266 /** 267 * st_i2c_hw_config() - Prepare SSC block, calculate and apply tuning timings 268 * @i2c_dev: Controller's private data 269 */ 270 static void st_i2c_hw_config(struct st_i2c_dev *i2c_dev) 271 { 272 unsigned long rate; 273 u32 val, ns_per_clk; 274 struct st_i2c_timings *t = &i2c_timings[i2c_dev->mode]; 275 276 st_i2c_soft_reset(i2c_dev); 277 278 val = SSC_CLR_REPSTRT | SSC_CLR_NACK | SSC_CLR_SSCARBL | 279 SSC_CLR_SSCAAS | SSC_CLR_SSCSTOP; 280 writel_relaxed(val, i2c_dev->base + SSC_CLR); 281 282 /* SSC Control register setup */ 283 val = SSC_CTL_PO | SSC_CTL_PH | SSC_CTL_HB | SSC_CTL_DATA_WIDTH_9; 284 writel_relaxed(val, i2c_dev->base + SSC_CTL); 285 286 rate = clk_get_rate(i2c_dev->clk); 287 ns_per_clk = 1000000000 / rate; 288 289 /* Baudrate */ 290 val = rate / (2 * t->rate); 291 writel_relaxed(val, i2c_dev->base + SSC_BRG); 292 293 /* Pre-scaler baudrate */ 294 writel_relaxed(1, i2c_dev->base + SSC_PRE_SCALER_BRG); 295 296 /* Enable I2C mode */ 297 writel_relaxed(SSC_I2C_I2CM, i2c_dev->base + SSC_I2C); 298 299 /* Repeated start hold time */ 300 val = t->rep_start_hold / ns_per_clk; 301 writel_relaxed(val, i2c_dev->base + SSC_REP_START_HOLD); 302 303 /* Repeated start set up time */ 304 val = t->rep_start_setup / ns_per_clk; 305 writel_relaxed(val, i2c_dev->base + SSC_REP_START_SETUP); 306 307 /* Start hold time */ 308 val = t->start_hold / ns_per_clk; 309 writel_relaxed(val, i2c_dev->base + SSC_START_HOLD); 310 311 /* Data set up time */ 312 val = t->data_setup_time / ns_per_clk; 313 writel_relaxed(val, i2c_dev->base + SSC_DATA_SETUP); 314 315 /* Stop set up time */ 316 val = t->stop_setup_time / ns_per_clk; 317 writel_relaxed(val, i2c_dev->base + SSC_STOP_SETUP); 318 319 /* Bus free time */ 320 val = t->bus_free_time / ns_per_clk; 321 writel_relaxed(val, i2c_dev->base + SSC_BUS_FREE); 322 323 /* Prescalers set up */ 324 val = rate / 10000000; 325 writel_relaxed(val, i2c_dev->base + SSC_PRSCALER); 326 writel_relaxed(val, i2c_dev->base + SSC_PRSCALER_DATAOUT); 327 328 /* Noise suppression witdh */ 329 val = i2c_dev->scl_min_width_us * rate / 100000000; 330 writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH); 331 332 /* Noise suppression max output data delay width */ 333 val = i2c_dev->sda_min_width_us * rate / 100000000; 334 writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT); 335 } 336 337 static int st_i2c_recover_bus(struct i2c_adapter *i2c_adap) 338 { 339 struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap); 340 u32 ctl; 341 342 dev_dbg(i2c_dev->dev, "Trying to recover bus\n"); 343 344 /* 345 * SSP IP is dual role SPI/I2C to generate 9 clock pulses 346 * we switch to SPI node, 9 bit words and write a 0. This 347 * has been validate with a oscilloscope and is easier 348 * than switching to GPIO mode. 349 */ 350 351 /* Disable interrupts */ 352 writel_relaxed(0, i2c_dev->base + SSC_IEN); 353 354 st_i2c_hw_config(i2c_dev); 355 356 ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO; 357 st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl); 358 359 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM); 360 usleep_range(8000, 10000); 361 362 writel_relaxed(0, i2c_dev->base + SSC_TBUF); 363 usleep_range(2000, 4000); 364 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM); 365 366 return 0; 367 } 368 369 static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev) 370 { 371 u32 sta; 372 int i, ret; 373 374 for (i = 0; i < 10; i++) { 375 sta = readl_relaxed(i2c_dev->base + SSC_STA); 376 if (!(sta & SSC_STA_BUSY)) 377 return 0; 378 379 usleep_range(2000, 4000); 380 } 381 382 dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta); 383 384 ret = i2c_recover_bus(&i2c_dev->adap); 385 if (ret) { 386 dev_err(i2c_dev->dev, "Failed to recover the bus (%d)\n", ret); 387 return ret; 388 } 389 390 return -EBUSY; 391 } 392 393 /** 394 * st_i2c_write_tx_fifo() - Write a byte in the Tx FIFO 395 * @i2c_dev: Controller's private data 396 * @byte: Data to write in the Tx FIFO 397 */ 398 static inline void st_i2c_write_tx_fifo(struct st_i2c_dev *i2c_dev, u8 byte) 399 { 400 u16 tbuf = byte << 1; 401 402 writel_relaxed(tbuf | 1, i2c_dev->base + SSC_TBUF); 403 } 404 405 /** 406 * st_i2c_wr_fill_tx_fifo() - Fill the Tx FIFO in write mode 407 * @i2c_dev: Controller's private data 408 * 409 * This functions fills the Tx FIFO with I2C transfert buffer when 410 * in write mode. 411 */ 412 static void st_i2c_wr_fill_tx_fifo(struct st_i2c_dev *i2c_dev) 413 { 414 struct st_i2c_client *c = &i2c_dev->client; 415 u32 tx_fstat, sta; 416 int i; 417 418 sta = readl_relaxed(i2c_dev->base + SSC_STA); 419 if (sta & SSC_STA_TX_FIFO_FULL) 420 return; 421 422 tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT); 423 tx_fstat &= SSC_TX_FSTAT_STATUS; 424 425 if (c->count < (SSC_TXFIFO_SIZE - tx_fstat)) 426 i = c->count; 427 else 428 i = SSC_TXFIFO_SIZE - tx_fstat; 429 430 for (; i > 0; i--, c->count--, c->buf++) 431 st_i2c_write_tx_fifo(i2c_dev, *c->buf); 432 } 433 434 /** 435 * st_i2c_rd_fill_tx_fifo() - Fill the Tx FIFO in read mode 436 * @i2c_dev: Controller's private data 437 * @max: Maximum amount of data to fill into the Tx FIFO 438 * 439 * This functions fills the Tx FIFO with fixed pattern when 440 * in read mode to trigger clock. 441 */ 442 static void st_i2c_rd_fill_tx_fifo(struct st_i2c_dev *i2c_dev, int max) 443 { 444 struct st_i2c_client *c = &i2c_dev->client; 445 u32 tx_fstat, sta; 446 int i; 447 448 sta = readl_relaxed(i2c_dev->base + SSC_STA); 449 if (sta & SSC_STA_TX_FIFO_FULL) 450 return; 451 452 tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT); 453 tx_fstat &= SSC_TX_FSTAT_STATUS; 454 455 if (max < (SSC_TXFIFO_SIZE - tx_fstat)) 456 i = max; 457 else 458 i = SSC_TXFIFO_SIZE - tx_fstat; 459 460 for (; i > 0; i--, c->xfered++) 461 st_i2c_write_tx_fifo(i2c_dev, 0xff); 462 } 463 464 static void st_i2c_read_rx_fifo(struct st_i2c_dev *i2c_dev) 465 { 466 struct st_i2c_client *c = &i2c_dev->client; 467 u32 i, sta; 468 u16 rbuf; 469 470 sta = readl_relaxed(i2c_dev->base + SSC_STA); 471 if (sta & SSC_STA_RIR) { 472 i = SSC_RXFIFO_SIZE; 473 } else { 474 i = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT); 475 i &= SSC_RX_FSTAT_STATUS; 476 } 477 478 for (; (i > 0) && (c->count > 0); i--, c->count--) { 479 rbuf = readl_relaxed(i2c_dev->base + SSC_RBUF) >> 1; 480 *c->buf++ = (u8)rbuf & 0xff; 481 } 482 483 if (i) { 484 dev_err(i2c_dev->dev, "Unexpected %d bytes in rx fifo\n", i); 485 st_i2c_flush_rx_fifo(i2c_dev); 486 } 487 } 488 489 /** 490 * st_i2c_terminate_xfer() - Send either STOP or REPSTART condition 491 * @i2c_dev: Controller's private data 492 */ 493 static void st_i2c_terminate_xfer(struct st_i2c_dev *i2c_dev) 494 { 495 struct st_i2c_client *c = &i2c_dev->client; 496 497 st_i2c_clr_bits(i2c_dev->base + SSC_IEN, SSC_IEN_TEEN); 498 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG); 499 500 if (c->stop) { 501 st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_STOPEN); 502 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); 503 } else { 504 st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_REPSTRTEN); 505 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_REPSTRTG); 506 } 507 } 508 509 /** 510 * st_i2c_handle_write() - Handle FIFO empty interrupt in case of write 511 * @i2c_dev: Controller's private data 512 */ 513 static void st_i2c_handle_write(struct st_i2c_dev *i2c_dev) 514 { 515 struct st_i2c_client *c = &i2c_dev->client; 516 517 st_i2c_flush_rx_fifo(i2c_dev); 518 519 if (!c->count) 520 /* End of xfer, send stop or repstart */ 521 st_i2c_terminate_xfer(i2c_dev); 522 else 523 st_i2c_wr_fill_tx_fifo(i2c_dev); 524 } 525 526 /** 527 * st_i2c_handle_read() - Handle FIFO empty interrupt in case of read 528 * @i2c_dev: Controller's private data 529 */ 530 static void st_i2c_handle_read(struct st_i2c_dev *i2c_dev) 531 { 532 struct st_i2c_client *c = &i2c_dev->client; 533 u32 ien; 534 535 /* Trash the address read back */ 536 if (!c->xfered) { 537 readl_relaxed(i2c_dev->base + SSC_RBUF); 538 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_TXENB); 539 } else { 540 st_i2c_read_rx_fifo(i2c_dev); 541 } 542 543 if (!c->count) { 544 /* End of xfer, send stop or repstart */ 545 st_i2c_terminate_xfer(i2c_dev); 546 } else if (c->count == 1) { 547 /* Penultimate byte to xfer, disable ACK gen. */ 548 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_ACKG); 549 550 /* Last received byte is to be handled by NACK interrupt */ 551 ien = SSC_IEN_NACKEN | SSC_IEN_ARBLEN; 552 writel_relaxed(ien, i2c_dev->base + SSC_IEN); 553 554 st_i2c_rd_fill_tx_fifo(i2c_dev, c->count); 555 } else { 556 st_i2c_rd_fill_tx_fifo(i2c_dev, c->count - 1); 557 } 558 } 559 560 /** 561 * st_i2c_isr_thread() - Interrupt routine 562 * @irq: interrupt number 563 * @data: Controller's private data 564 */ 565 static irqreturn_t st_i2c_isr_thread(int irq, void *data) 566 { 567 struct st_i2c_dev *i2c_dev = data; 568 struct st_i2c_client *c = &i2c_dev->client; 569 u32 sta, ien; 570 int it; 571 572 ien = readl_relaxed(i2c_dev->base + SSC_IEN); 573 sta = readl_relaxed(i2c_dev->base + SSC_STA); 574 575 /* Use __fls() to check error bits first */ 576 it = __fls(sta & ien); 577 if (it < 0) { 578 dev_dbg(i2c_dev->dev, "spurious it (sta=0x%04x, ien=0x%04x)\n", 579 sta, ien); 580 return IRQ_NONE; 581 } 582 583 switch (1 << it) { 584 case SSC_STA_TE: 585 if (c->addr & I2C_M_RD) 586 st_i2c_handle_read(i2c_dev); 587 else 588 st_i2c_handle_write(i2c_dev); 589 break; 590 591 case SSC_STA_STOP: 592 case SSC_STA_REPSTRT: 593 writel_relaxed(0, i2c_dev->base + SSC_IEN); 594 complete(&i2c_dev->complete); 595 break; 596 597 case SSC_STA_NACK: 598 writel_relaxed(SSC_CLR_NACK, i2c_dev->base + SSC_CLR); 599 600 /* Last received byte handled by NACK interrupt */ 601 if ((c->addr & I2C_M_RD) && (c->count == 1) && (c->xfered)) { 602 st_i2c_handle_read(i2c_dev); 603 break; 604 } 605 606 it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN; 607 writel_relaxed(it, i2c_dev->base + SSC_IEN); 608 609 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); 610 c->result = -EIO; 611 break; 612 613 case SSC_STA_ARBL: 614 writel_relaxed(SSC_CLR_SSCARBL, i2c_dev->base + SSC_CLR); 615 616 it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN; 617 writel_relaxed(it, i2c_dev->base + SSC_IEN); 618 619 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); 620 c->result = -EAGAIN; 621 break; 622 623 default: 624 dev_err(i2c_dev->dev, 625 "it %d unhandled (sta=0x%04x)\n", it, sta); 626 } 627 628 /* 629 * Read IEN register to ensure interrupt mask write is effective 630 * before re-enabling interrupt at GIC level, and thus avoid spurious 631 * interrupts. 632 */ 633 readl(i2c_dev->base + SSC_IEN); 634 635 return IRQ_HANDLED; 636 } 637 638 /** 639 * st_i2c_xfer_msg() - Transfer a single I2C message 640 * @i2c_dev: Controller's private data 641 * @msg: I2C message to transfer 642 * @is_first: first message of the sequence 643 * @is_last: last message of the sequence 644 */ 645 static int st_i2c_xfer_msg(struct st_i2c_dev *i2c_dev, struct i2c_msg *msg, 646 bool is_first, bool is_last) 647 { 648 struct st_i2c_client *c = &i2c_dev->client; 649 u32 ctl, i2c, it; 650 unsigned long timeout; 651 int ret; 652 653 c->addr = i2c_8bit_addr_from_msg(msg); 654 c->buf = msg->buf; 655 c->count = msg->len; 656 c->xfered = 0; 657 c->result = 0; 658 c->stop = is_last; 659 660 reinit_completion(&i2c_dev->complete); 661 662 ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO; 663 st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl); 664 665 i2c = SSC_I2C_TXENB; 666 if (c->addr & I2C_M_RD) 667 i2c |= SSC_I2C_ACKG; 668 st_i2c_set_bits(i2c_dev->base + SSC_I2C, i2c); 669 670 /* Write slave address */ 671 st_i2c_write_tx_fifo(i2c_dev, c->addr); 672 673 /* Pre-fill Tx fifo with data in case of write */ 674 if (!(c->addr & I2C_M_RD)) 675 st_i2c_wr_fill_tx_fifo(i2c_dev); 676 677 it = SSC_IEN_NACKEN | SSC_IEN_TEEN | SSC_IEN_ARBLEN; 678 writel_relaxed(it, i2c_dev->base + SSC_IEN); 679 680 if (is_first) { 681 ret = st_i2c_wait_free_bus(i2c_dev); 682 if (ret) 683 return ret; 684 685 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG); 686 } 687 688 timeout = wait_for_completion_timeout(&i2c_dev->complete, 689 i2c_dev->adap.timeout); 690 ret = c->result; 691 692 if (!timeout) { 693 dev_err(i2c_dev->dev, "Write to slave 0x%x timed out\n", 694 c->addr); 695 ret = -ETIMEDOUT; 696 } 697 698 i2c = SSC_I2C_STOPG | SSC_I2C_REPSTRTG; 699 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, i2c); 700 701 writel_relaxed(SSC_CLR_SSCSTOP | SSC_CLR_REPSTRT, 702 i2c_dev->base + SSC_CLR); 703 704 return ret; 705 } 706 707 /** 708 * st_i2c_xfer() - Transfer a single I2C message 709 * @i2c_adap: Adapter pointer to the controller 710 * @msgs: Pointer to data to be written. 711 * @num: Number of messages to be executed 712 */ 713 static int st_i2c_xfer(struct i2c_adapter *i2c_adap, 714 struct i2c_msg msgs[], int num) 715 { 716 struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap); 717 int ret, i; 718 719 i2c_dev->busy = true; 720 721 ret = clk_prepare_enable(i2c_dev->clk); 722 if (ret) { 723 dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n"); 724 return ret; 725 } 726 727 pinctrl_pm_select_default_state(i2c_dev->dev); 728 729 st_i2c_hw_config(i2c_dev); 730 731 for (i = 0; (i < num) && !ret; i++) 732 ret = st_i2c_xfer_msg(i2c_dev, &msgs[i], i == 0, i == num - 1); 733 734 pinctrl_pm_select_idle_state(i2c_dev->dev); 735 736 clk_disable_unprepare(i2c_dev->clk); 737 738 i2c_dev->busy = false; 739 740 return (ret < 0) ? ret : i; 741 } 742 743 static int st_i2c_suspend(struct device *dev) 744 { 745 struct st_i2c_dev *i2c_dev = dev_get_drvdata(dev); 746 747 if (i2c_dev->busy) 748 return -EBUSY; 749 750 pinctrl_pm_select_sleep_state(dev); 751 752 return 0; 753 } 754 755 static int st_i2c_resume(struct device *dev) 756 { 757 pinctrl_pm_select_default_state(dev); 758 /* Go in idle state if available */ 759 pinctrl_pm_select_idle_state(dev); 760 761 return 0; 762 } 763 764 static DEFINE_SIMPLE_DEV_PM_OPS(st_i2c_pm, st_i2c_suspend, st_i2c_resume); 765 766 static u32 st_i2c_func(struct i2c_adapter *adap) 767 { 768 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; 769 } 770 771 static const struct i2c_algorithm st_i2c_algo = { 772 .master_xfer = st_i2c_xfer, 773 .functionality = st_i2c_func, 774 }; 775 776 static struct i2c_bus_recovery_info st_i2c_recovery_info = { 777 .recover_bus = st_i2c_recover_bus, 778 }; 779 780 static int st_i2c_of_get_deglitch(struct device_node *np, 781 struct st_i2c_dev *i2c_dev) 782 { 783 int ret; 784 785 ret = of_property_read_u32(np, "st,i2c-min-scl-pulse-width-us", 786 &i2c_dev->scl_min_width_us); 787 if ((ret == -ENODATA) || (ret == -EOVERFLOW)) { 788 dev_err(i2c_dev->dev, "st,i2c-min-scl-pulse-width-us invalid\n"); 789 return ret; 790 } 791 792 ret = of_property_read_u32(np, "st,i2c-min-sda-pulse-width-us", 793 &i2c_dev->sda_min_width_us); 794 if ((ret == -ENODATA) || (ret == -EOVERFLOW)) { 795 dev_err(i2c_dev->dev, "st,i2c-min-sda-pulse-width-us invalid\n"); 796 return ret; 797 } 798 799 return 0; 800 } 801 802 static int st_i2c_probe(struct platform_device *pdev) 803 { 804 struct device_node *np = pdev->dev.of_node; 805 struct st_i2c_dev *i2c_dev; 806 struct resource *res; 807 u32 clk_rate; 808 struct i2c_adapter *adap; 809 int ret; 810 811 i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); 812 if (!i2c_dev) 813 return -ENOMEM; 814 815 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 816 i2c_dev->base = devm_ioremap_resource(&pdev->dev, res); 817 if (IS_ERR(i2c_dev->base)) 818 return PTR_ERR(i2c_dev->base); 819 820 i2c_dev->irq = irq_of_parse_and_map(np, 0); 821 if (!i2c_dev->irq) { 822 dev_err(&pdev->dev, "IRQ missing or invalid\n"); 823 return -EINVAL; 824 } 825 826 i2c_dev->clk = of_clk_get_by_name(np, "ssc"); 827 if (IS_ERR(i2c_dev->clk)) { 828 dev_err(&pdev->dev, "Unable to request clock\n"); 829 return PTR_ERR(i2c_dev->clk); 830 } 831 832 i2c_dev->mode = I2C_MODE_STANDARD; 833 ret = of_property_read_u32(np, "clock-frequency", &clk_rate); 834 if (!ret && (clk_rate == I2C_MAX_FAST_MODE_FREQ)) 835 i2c_dev->mode = I2C_MODE_FAST; 836 837 i2c_dev->dev = &pdev->dev; 838 839 ret = devm_request_threaded_irq(&pdev->dev, i2c_dev->irq, 840 NULL, st_i2c_isr_thread, 841 IRQF_ONESHOT, pdev->name, i2c_dev); 842 if (ret) { 843 dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq); 844 return ret; 845 } 846 847 pinctrl_pm_select_default_state(i2c_dev->dev); 848 /* In case idle state available, select it */ 849 pinctrl_pm_select_idle_state(i2c_dev->dev); 850 851 ret = st_i2c_of_get_deglitch(np, i2c_dev); 852 if (ret) 853 return ret; 854 855 adap = &i2c_dev->adap; 856 i2c_set_adapdata(adap, i2c_dev); 857 snprintf(adap->name, sizeof(adap->name), "ST I2C(%pa)", &res->start); 858 adap->owner = THIS_MODULE; 859 adap->timeout = 2 * HZ; 860 adap->retries = 0; 861 adap->algo = &st_i2c_algo; 862 adap->bus_recovery_info = &st_i2c_recovery_info; 863 adap->dev.parent = &pdev->dev; 864 adap->dev.of_node = pdev->dev.of_node; 865 866 init_completion(&i2c_dev->complete); 867 868 ret = i2c_add_adapter(adap); 869 if (ret) 870 return ret; 871 872 platform_set_drvdata(pdev, i2c_dev); 873 874 dev_info(i2c_dev->dev, "%s initialized\n", adap->name); 875 876 return 0; 877 } 878 879 static void st_i2c_remove(struct platform_device *pdev) 880 { 881 struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev); 882 883 i2c_del_adapter(&i2c_dev->adap); 884 } 885 886 static const struct of_device_id st_i2c_match[] = { 887 { .compatible = "st,comms-ssc-i2c", }, 888 { .compatible = "st,comms-ssc4-i2c", }, 889 {}, 890 }; 891 MODULE_DEVICE_TABLE(of, st_i2c_match); 892 893 static struct platform_driver st_i2c_driver = { 894 .driver = { 895 .name = "st-i2c", 896 .of_match_table = st_i2c_match, 897 .pm = pm_sleep_ptr(&st_i2c_pm), 898 }, 899 .probe = st_i2c_probe, 900 .remove_new = st_i2c_remove, 901 }; 902 903 module_platform_driver(st_i2c_driver); 904 905 MODULE_AUTHOR("Maxime Coquelin <maxime.coquelin@st.com>"); 906 MODULE_DESCRIPTION("STMicroelectronics I2C driver"); 907 MODULE_LICENSE("GPL v2"); 908