1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * TI DAVINCI I2C adapter driver. 4 * 5 * Copyright (C) 2006 Texas Instruments. 6 * Copyright (C) 2007 MontaVista Software Inc. 7 * 8 * Updated by Vinod & Sudhakar Feb 2005 9 * 10 * ---------------------------------------------------------------------------- 11 * 12 * ---------------------------------------------------------------------------- 13 */ 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/delay.h> 17 #include <linux/i2c.h> 18 #include <linux/clk.h> 19 #include <linux/errno.h> 20 #include <linux/sched.h> 21 #include <linux/err.h> 22 #include <linux/interrupt.h> 23 #include <linux/platform_device.h> 24 #include <linux/io.h> 25 #include <linux/slab.h> 26 #include <linux/cpufreq.h> 27 #include <linux/gpio/consumer.h> 28 #include <linux/of_device.h> 29 #include <linux/platform_data/i2c-davinci.h> 30 #include <linux/pm_runtime.h> 31 32 /* ----- global defines ----------------------------------------------- */ 33 34 #define DAVINCI_I2C_TIMEOUT (1*HZ) 35 #define DAVINCI_I2C_MAX_TRIES 2 36 #define DAVINCI_I2C_OWN_ADDRESS 0x08 37 #define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_SCD | \ 38 DAVINCI_I2C_IMR_ARDY | \ 39 DAVINCI_I2C_IMR_NACK | \ 40 DAVINCI_I2C_IMR_AL) 41 42 #define DAVINCI_I2C_OAR_REG 0x00 43 #define DAVINCI_I2C_IMR_REG 0x04 44 #define DAVINCI_I2C_STR_REG 0x08 45 #define DAVINCI_I2C_CLKL_REG 0x0c 46 #define DAVINCI_I2C_CLKH_REG 0x10 47 #define DAVINCI_I2C_CNT_REG 0x14 48 #define DAVINCI_I2C_DRR_REG 0x18 49 #define DAVINCI_I2C_SAR_REG 0x1c 50 #define DAVINCI_I2C_DXR_REG 0x20 51 #define DAVINCI_I2C_MDR_REG 0x24 52 #define DAVINCI_I2C_IVR_REG 0x28 53 #define DAVINCI_I2C_EMDR_REG 0x2c 54 #define DAVINCI_I2C_PSC_REG 0x30 55 #define DAVINCI_I2C_FUNC_REG 0x48 56 #define DAVINCI_I2C_DIR_REG 0x4c 57 #define DAVINCI_I2C_DIN_REG 0x50 58 #define DAVINCI_I2C_DOUT_REG 0x54 59 #define DAVINCI_I2C_DSET_REG 0x58 60 #define DAVINCI_I2C_DCLR_REG 0x5c 61 62 #define DAVINCI_I2C_IVR_AAS 0x07 63 #define DAVINCI_I2C_IVR_SCD 0x06 64 #define DAVINCI_I2C_IVR_XRDY 0x05 65 #define DAVINCI_I2C_IVR_RDR 0x04 66 #define DAVINCI_I2C_IVR_ARDY 0x03 67 #define DAVINCI_I2C_IVR_NACK 0x02 68 #define DAVINCI_I2C_IVR_AL 0x01 69 70 #define DAVINCI_I2C_STR_BB BIT(12) 71 #define DAVINCI_I2C_STR_RSFULL BIT(11) 72 #define DAVINCI_I2C_STR_SCD BIT(5) 73 #define DAVINCI_I2C_STR_ARDY BIT(2) 74 #define DAVINCI_I2C_STR_NACK BIT(1) 75 #define DAVINCI_I2C_STR_AL BIT(0) 76 77 #define DAVINCI_I2C_MDR_NACK BIT(15) 78 #define DAVINCI_I2C_MDR_STT BIT(13) 79 #define DAVINCI_I2C_MDR_STP BIT(11) 80 #define DAVINCI_I2C_MDR_MST BIT(10) 81 #define DAVINCI_I2C_MDR_TRX BIT(9) 82 #define DAVINCI_I2C_MDR_XA BIT(8) 83 #define DAVINCI_I2C_MDR_RM BIT(7) 84 #define DAVINCI_I2C_MDR_IRS BIT(5) 85 86 #define DAVINCI_I2C_IMR_AAS BIT(6) 87 #define DAVINCI_I2C_IMR_SCD BIT(5) 88 #define DAVINCI_I2C_IMR_XRDY BIT(4) 89 #define DAVINCI_I2C_IMR_RRDY BIT(3) 90 #define DAVINCI_I2C_IMR_ARDY BIT(2) 91 #define DAVINCI_I2C_IMR_NACK BIT(1) 92 #define DAVINCI_I2C_IMR_AL BIT(0) 93 94 /* set SDA and SCL as GPIO */ 95 #define DAVINCI_I2C_FUNC_PFUNC0 BIT(0) 96 97 /* set SCL as output when used as GPIO*/ 98 #define DAVINCI_I2C_DIR_PDIR0 BIT(0) 99 /* set SDA as output when used as GPIO*/ 100 #define DAVINCI_I2C_DIR_PDIR1 BIT(1) 101 102 /* read SCL GPIO level */ 103 #define DAVINCI_I2C_DIN_PDIN0 BIT(0) 104 /* read SDA GPIO level */ 105 #define DAVINCI_I2C_DIN_PDIN1 BIT(1) 106 107 /*set the SCL GPIO high */ 108 #define DAVINCI_I2C_DSET_PDSET0 BIT(0) 109 /*set the SDA GPIO high */ 110 #define DAVINCI_I2C_DSET_PDSET1 BIT(1) 111 112 /* set the SCL GPIO low */ 113 #define DAVINCI_I2C_DCLR_PDCLR0 BIT(0) 114 /* set the SDA GPIO low */ 115 #define DAVINCI_I2C_DCLR_PDCLR1 BIT(1) 116 117 /* timeout for pm runtime autosuspend */ 118 #define DAVINCI_I2C_PM_TIMEOUT 1000 /* ms */ 119 120 struct davinci_i2c_dev { 121 struct device *dev; 122 void __iomem *base; 123 struct completion cmd_complete; 124 struct clk *clk; 125 int cmd_err; 126 u8 *buf; 127 size_t buf_len; 128 int irq; 129 int stop; 130 u8 terminate; 131 struct i2c_adapter adapter; 132 #ifdef CONFIG_CPU_FREQ 133 struct notifier_block freq_transition; 134 #endif 135 struct davinci_i2c_platform_data *pdata; 136 }; 137 138 /* default platform data to use if not supplied in the platform_device */ 139 static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = { 140 .bus_freq = 100, 141 .bus_delay = 0, 142 }; 143 144 static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev, 145 int reg, u16 val) 146 { 147 writew_relaxed(val, i2c_dev->base + reg); 148 } 149 150 static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg) 151 { 152 return readw_relaxed(i2c_dev->base + reg); 153 } 154 155 static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev, 156 int val) 157 { 158 u16 w; 159 160 w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG); 161 if (!val) /* put I2C into reset */ 162 w &= ~DAVINCI_I2C_MDR_IRS; 163 else /* take I2C out of reset */ 164 w |= DAVINCI_I2C_MDR_IRS; 165 166 davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w); 167 } 168 169 static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev) 170 { 171 struct davinci_i2c_platform_data *pdata = dev->pdata; 172 u16 psc; 173 u32 clk; 174 u32 d; 175 u32 clkh; 176 u32 clkl; 177 u32 input_clock = clk_get_rate(dev->clk); 178 struct device_node *of_node = dev->dev->of_node; 179 180 /* NOTE: I2C Clock divider programming info 181 * As per I2C specs the following formulas provide prescaler 182 * and low/high divider values 183 * input clk --> PSC Div -----------> ICCL/H Div --> output clock 184 * module clk 185 * 186 * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ] 187 * 188 * Thus, 189 * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d; 190 * 191 * where if PSC == 0, d = 7, 192 * if PSC == 1, d = 6 193 * if PSC > 1 , d = 5 194 * 195 * Note: 196 * d is always 6 on Keystone I2C controller 197 */ 198 199 /* 200 * Both Davinci and current Keystone User Guides recommend a value 201 * between 7MHz and 12MHz. In reality 7MHz module clock doesn't 202 * always produce enough margin between SDA and SCL transitions. 203 * Measurements show that the higher the module clock is, the 204 * bigger is the margin, providing more reliable communication. 205 * So we better target for 12MHz. 206 */ 207 psc = (input_clock / 12000000) - 1; 208 if ((input_clock / (psc + 1)) > 12000000) 209 psc++; /* better to run under spec than over */ 210 d = (psc >= 2) ? 5 : 7 - psc; 211 212 if (of_node && of_device_is_compatible(of_node, "ti,keystone-i2c")) 213 d = 6; 214 215 clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)); 216 /* Avoid driving the bus too fast because of rounding errors above */ 217 if (input_clock / (psc + 1) / clk > pdata->bus_freq * 1000) 218 clk++; 219 /* 220 * According to I2C-BUS Spec 2.1, in FAST-MODE LOW period should be at 221 * least 1.3uS, which is not the case with 50% duty cycle. Driving HIGH 222 * to LOW ratio as 1 to 2 is more safe. 223 */ 224 if (pdata->bus_freq > 100) 225 clkl = (clk << 1) / 3; 226 else 227 clkl = (clk >> 1); 228 /* 229 * It's not always possible to have 1 to 2 ratio when d=7, so fall back 230 * to minimal possible clkh in this case. 231 * 232 * Note: 233 * CLKH is not allowed to be 0, in this case I2C clock is not generated 234 * at all 235 */ 236 if (clk > clkl + d) { 237 clkh = clk - clkl - d; 238 clkl -= d; 239 } else { 240 clkh = 1; 241 clkl = clk - (d << 1); 242 } 243 244 davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc); 245 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh); 246 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl); 247 248 dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk); 249 } 250 251 /* 252 * This function configures I2C and brings I2C out of reset. 253 * This function is called during I2C init function. This function 254 * also gets called if I2C encounters any errors. 255 */ 256 static int i2c_davinci_init(struct davinci_i2c_dev *dev) 257 { 258 struct davinci_i2c_platform_data *pdata = dev->pdata; 259 260 /* put I2C into reset */ 261 davinci_i2c_reset_ctrl(dev, 0); 262 263 /* compute clock dividers */ 264 i2c_davinci_calc_clk_dividers(dev); 265 266 /* Respond at reserved "SMBus Host" slave address" (and zero); 267 * we seem to have no option to not respond... 268 */ 269 davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, DAVINCI_I2C_OWN_ADDRESS); 270 271 dev_dbg(dev->dev, "PSC = %d\n", 272 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG)); 273 dev_dbg(dev->dev, "CLKL = %d\n", 274 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG)); 275 dev_dbg(dev->dev, "CLKH = %d\n", 276 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG)); 277 dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n", 278 pdata->bus_freq, pdata->bus_delay); 279 280 281 /* Take the I2C module out of reset: */ 282 davinci_i2c_reset_ctrl(dev, 1); 283 284 /* Enable interrupts */ 285 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL); 286 287 return 0; 288 } 289 290 /* 291 * This routine does i2c bus recovery by using i2c_generic_scl_recovery 292 * which is provided by I2C Bus recovery infrastructure. 293 */ 294 static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap) 295 { 296 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); 297 298 /* Disable interrupts */ 299 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, 0); 300 301 /* put I2C into reset */ 302 davinci_i2c_reset_ctrl(dev, 0); 303 } 304 305 static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap) 306 { 307 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); 308 309 i2c_davinci_init(dev); 310 } 311 312 static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = { 313 .recover_bus = i2c_generic_scl_recovery, 314 .prepare_recovery = davinci_i2c_prepare_recovery, 315 .unprepare_recovery = davinci_i2c_unprepare_recovery, 316 }; 317 318 static void davinci_i2c_set_scl(struct i2c_adapter *adap, int val) 319 { 320 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); 321 322 if (val) 323 davinci_i2c_write_reg(dev, DAVINCI_I2C_DSET_REG, 324 DAVINCI_I2C_DSET_PDSET0); 325 else 326 davinci_i2c_write_reg(dev, DAVINCI_I2C_DCLR_REG, 327 DAVINCI_I2C_DCLR_PDCLR0); 328 } 329 330 static int davinci_i2c_get_scl(struct i2c_adapter *adap) 331 { 332 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); 333 int val; 334 335 /* read the state of SCL */ 336 val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG); 337 return val & DAVINCI_I2C_DIN_PDIN0; 338 } 339 340 static int davinci_i2c_get_sda(struct i2c_adapter *adap) 341 { 342 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); 343 int val; 344 345 /* read the state of SDA */ 346 val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG); 347 return val & DAVINCI_I2C_DIN_PDIN1; 348 } 349 350 static void davinci_i2c_scl_prepare_recovery(struct i2c_adapter *adap) 351 { 352 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); 353 354 davinci_i2c_prepare_recovery(adap); 355 356 /* SCL output, SDA input */ 357 davinci_i2c_write_reg(dev, DAVINCI_I2C_DIR_REG, DAVINCI_I2C_DIR_PDIR0); 358 359 /* change to GPIO mode */ 360 davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG, 361 DAVINCI_I2C_FUNC_PFUNC0); 362 } 363 364 static void davinci_i2c_scl_unprepare_recovery(struct i2c_adapter *adap) 365 { 366 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); 367 368 /* change back to I2C mode */ 369 davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG, 0); 370 371 davinci_i2c_unprepare_recovery(adap); 372 } 373 374 static struct i2c_bus_recovery_info davinci_i2c_scl_recovery_info = { 375 .recover_bus = i2c_generic_scl_recovery, 376 .set_scl = davinci_i2c_set_scl, 377 .get_scl = davinci_i2c_get_scl, 378 .get_sda = davinci_i2c_get_sda, 379 .prepare_recovery = davinci_i2c_scl_prepare_recovery, 380 .unprepare_recovery = davinci_i2c_scl_unprepare_recovery, 381 }; 382 383 /* 384 * Waiting for bus not busy 385 */ 386 static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev) 387 { 388 unsigned long timeout = jiffies + dev->adapter.timeout; 389 390 do { 391 if (!(davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB)) 392 return 0; 393 schedule_timeout_uninterruptible(1); 394 } while (time_before_eq(jiffies, timeout)); 395 396 dev_warn(dev->dev, "timeout waiting for bus ready\n"); 397 i2c_recover_bus(&dev->adapter); 398 399 /* 400 * if bus is still "busy" here, it's most probably a HW problem like 401 * short-circuit 402 */ 403 if (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB) 404 return -EIO; 405 406 return 0; 407 } 408 409 /* 410 * Low level master read/write transaction. This function is called 411 * from i2c_davinci_xfer. 412 */ 413 static int 414 i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) 415 { 416 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); 417 struct davinci_i2c_platform_data *pdata = dev->pdata; 418 u32 flag; 419 u16 w; 420 unsigned long time_left; 421 422 if (msg->addr == DAVINCI_I2C_OWN_ADDRESS) { 423 dev_warn(dev->dev, "transfer to own address aborted\n"); 424 return -EADDRNOTAVAIL; 425 } 426 427 /* Introduce a delay, required for some boards (e.g Davinci EVM) */ 428 if (pdata->bus_delay) 429 udelay(pdata->bus_delay); 430 431 /* set the slave address */ 432 davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr); 433 434 dev->buf = msg->buf; 435 dev->buf_len = msg->len; 436 dev->stop = stop; 437 438 davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len); 439 440 reinit_completion(&dev->cmd_complete); 441 dev->cmd_err = 0; 442 443 /* Take I2C out of reset and configure it as master */ 444 flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST; 445 446 /* if the slave address is ten bit address, enable XA bit */ 447 if (msg->flags & I2C_M_TEN) 448 flag |= DAVINCI_I2C_MDR_XA; 449 if (!(msg->flags & I2C_M_RD)) 450 flag |= DAVINCI_I2C_MDR_TRX; 451 if (msg->len == 0) 452 flag |= DAVINCI_I2C_MDR_RM; 453 454 /* Enable receive or transmit interrupts */ 455 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG); 456 if (msg->flags & I2C_M_RD) 457 w |= DAVINCI_I2C_IMR_RRDY; 458 else 459 w |= DAVINCI_I2C_IMR_XRDY; 460 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); 461 462 dev->terminate = 0; 463 464 /* 465 * Write mode register first as needed for correct behaviour 466 * on OMAP-L138, but don't set STT yet to avoid a race with XRDY 467 * occurring before we have loaded DXR 468 */ 469 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); 470 471 /* 472 * First byte should be set here, not after interrupt, 473 * because transmit-data-ready interrupt can come before 474 * NACK-interrupt during sending of previous message and 475 * ICDXR may have wrong data 476 * It also saves us one interrupt, slightly faster 477 */ 478 if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) { 479 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++); 480 dev->buf_len--; 481 } 482 483 /* Set STT to begin transmit now DXR is loaded */ 484 flag |= DAVINCI_I2C_MDR_STT; 485 if (stop && msg->len != 0) 486 flag |= DAVINCI_I2C_MDR_STP; 487 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); 488 489 time_left = wait_for_completion_timeout(&dev->cmd_complete, 490 dev->adapter.timeout); 491 if (!time_left) { 492 dev_err(dev->dev, "controller timed out\n"); 493 i2c_recover_bus(adap); 494 dev->buf_len = 0; 495 return -ETIMEDOUT; 496 } 497 if (dev->buf_len) { 498 /* This should be 0 if all bytes were transferred 499 * or dev->cmd_err denotes an error. 500 */ 501 dev_err(dev->dev, "abnormal termination buf_len=%zu\n", 502 dev->buf_len); 503 dev->terminate = 1; 504 wmb(); 505 dev->buf_len = 0; 506 return -EREMOTEIO; 507 } 508 509 /* no error */ 510 if (likely(!dev->cmd_err)) 511 return msg->len; 512 513 /* We have an error */ 514 if (dev->cmd_err & DAVINCI_I2C_STR_AL) { 515 i2c_davinci_init(dev); 516 return -EIO; 517 } 518 519 if (dev->cmd_err & DAVINCI_I2C_STR_NACK) { 520 if (msg->flags & I2C_M_IGNORE_NAK) 521 return msg->len; 522 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); 523 w |= DAVINCI_I2C_MDR_STP; 524 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); 525 return -EREMOTEIO; 526 } 527 return -EIO; 528 } 529 530 /* 531 * Prepare controller for a transaction and call i2c_davinci_xfer_msg 532 */ 533 static int 534 i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) 535 { 536 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); 537 int i; 538 int ret; 539 540 dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num); 541 542 ret = pm_runtime_resume_and_get(dev->dev); 543 if (ret < 0) { 544 dev_err(dev->dev, "Failed to runtime_get device: %d\n", ret); 545 return ret; 546 } 547 548 ret = i2c_davinci_wait_bus_not_busy(dev); 549 if (ret < 0) { 550 dev_warn(dev->dev, "timeout waiting for bus ready\n"); 551 goto out; 552 } 553 554 for (i = 0; i < num; i++) { 555 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1))); 556 dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num, 557 ret); 558 if (ret < 0) 559 goto out; 560 } 561 562 ret = num; 563 564 out: 565 pm_runtime_mark_last_busy(dev->dev); 566 pm_runtime_put_autosuspend(dev->dev); 567 568 return ret; 569 } 570 571 static u32 i2c_davinci_func(struct i2c_adapter *adap) 572 { 573 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; 574 } 575 576 static void terminate_read(struct davinci_i2c_dev *dev) 577 { 578 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); 579 w |= DAVINCI_I2C_MDR_NACK; 580 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); 581 582 /* Throw away data */ 583 davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG); 584 if (!dev->terminate) 585 dev_err(dev->dev, "RDR IRQ while no data requested\n"); 586 } 587 static void terminate_write(struct davinci_i2c_dev *dev) 588 { 589 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); 590 w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP; 591 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); 592 593 if (!dev->terminate) 594 dev_dbg(dev->dev, "TDR IRQ while no data to send\n"); 595 } 596 597 /* 598 * Interrupt service routine. This gets called whenever an I2C interrupt 599 * occurs. 600 */ 601 static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id) 602 { 603 struct davinci_i2c_dev *dev = dev_id; 604 u32 stat; 605 int count = 0; 606 u16 w; 607 608 if (pm_runtime_suspended(dev->dev)) 609 return IRQ_NONE; 610 611 while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) { 612 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat); 613 if (count++ == 100) { 614 dev_warn(dev->dev, "Too much work in one IRQ\n"); 615 break; 616 } 617 618 switch (stat) { 619 case DAVINCI_I2C_IVR_AL: 620 /* Arbitration lost, must retry */ 621 dev->cmd_err |= DAVINCI_I2C_STR_AL; 622 dev->buf_len = 0; 623 complete(&dev->cmd_complete); 624 break; 625 626 case DAVINCI_I2C_IVR_NACK: 627 dev->cmd_err |= DAVINCI_I2C_STR_NACK; 628 dev->buf_len = 0; 629 complete(&dev->cmd_complete); 630 break; 631 632 case DAVINCI_I2C_IVR_ARDY: 633 davinci_i2c_write_reg(dev, 634 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY); 635 if (((dev->buf_len == 0) && (dev->stop != 0)) || 636 (dev->cmd_err & DAVINCI_I2C_STR_NACK)) { 637 w = davinci_i2c_read_reg(dev, 638 DAVINCI_I2C_MDR_REG); 639 w |= DAVINCI_I2C_MDR_STP; 640 davinci_i2c_write_reg(dev, 641 DAVINCI_I2C_MDR_REG, w); 642 } 643 complete(&dev->cmd_complete); 644 break; 645 646 case DAVINCI_I2C_IVR_RDR: 647 if (dev->buf_len) { 648 *dev->buf++ = 649 davinci_i2c_read_reg(dev, 650 DAVINCI_I2C_DRR_REG); 651 dev->buf_len--; 652 if (dev->buf_len) 653 continue; 654 655 davinci_i2c_write_reg(dev, 656 DAVINCI_I2C_STR_REG, 657 DAVINCI_I2C_IMR_RRDY); 658 } else { 659 /* signal can terminate transfer */ 660 terminate_read(dev); 661 } 662 break; 663 664 case DAVINCI_I2C_IVR_XRDY: 665 if (dev->buf_len) { 666 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, 667 *dev->buf++); 668 dev->buf_len--; 669 if (dev->buf_len) 670 continue; 671 672 w = davinci_i2c_read_reg(dev, 673 DAVINCI_I2C_IMR_REG); 674 w &= ~DAVINCI_I2C_IMR_XRDY; 675 davinci_i2c_write_reg(dev, 676 DAVINCI_I2C_IMR_REG, 677 w); 678 } else { 679 /* signal can terminate transfer */ 680 terminate_write(dev); 681 } 682 break; 683 684 case DAVINCI_I2C_IVR_SCD: 685 davinci_i2c_write_reg(dev, 686 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD); 687 complete(&dev->cmd_complete); 688 break; 689 690 case DAVINCI_I2C_IVR_AAS: 691 dev_dbg(dev->dev, "Address as slave interrupt\n"); 692 break; 693 694 default: 695 dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat); 696 break; 697 } 698 } 699 700 return count ? IRQ_HANDLED : IRQ_NONE; 701 } 702 703 #ifdef CONFIG_CPU_FREQ 704 static int i2c_davinci_cpufreq_transition(struct notifier_block *nb, 705 unsigned long val, void *data) 706 { 707 struct davinci_i2c_dev *dev; 708 709 dev = container_of(nb, struct davinci_i2c_dev, freq_transition); 710 711 i2c_lock_bus(&dev->adapter, I2C_LOCK_ROOT_ADAPTER); 712 if (val == CPUFREQ_PRECHANGE) { 713 davinci_i2c_reset_ctrl(dev, 0); 714 } else if (val == CPUFREQ_POSTCHANGE) { 715 i2c_davinci_calc_clk_dividers(dev); 716 davinci_i2c_reset_ctrl(dev, 1); 717 } 718 i2c_unlock_bus(&dev->adapter, I2C_LOCK_ROOT_ADAPTER); 719 720 return 0; 721 } 722 723 static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev) 724 { 725 dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition; 726 727 return cpufreq_register_notifier(&dev->freq_transition, 728 CPUFREQ_TRANSITION_NOTIFIER); 729 } 730 731 static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev) 732 { 733 cpufreq_unregister_notifier(&dev->freq_transition, 734 CPUFREQ_TRANSITION_NOTIFIER); 735 } 736 #else 737 static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev) 738 { 739 return 0; 740 } 741 742 static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev) 743 { 744 } 745 #endif 746 747 static const struct i2c_algorithm i2c_davinci_algo = { 748 .master_xfer = i2c_davinci_xfer, 749 .functionality = i2c_davinci_func, 750 }; 751 752 static const struct of_device_id davinci_i2c_of_match[] = { 753 {.compatible = "ti,davinci-i2c", }, 754 {.compatible = "ti,keystone-i2c", }, 755 {}, 756 }; 757 MODULE_DEVICE_TABLE(of, davinci_i2c_of_match); 758 759 static int davinci_i2c_probe(struct platform_device *pdev) 760 { 761 struct davinci_i2c_dev *dev; 762 struct i2c_adapter *adap; 763 struct i2c_bus_recovery_info *rinfo; 764 int r, irq; 765 766 irq = platform_get_irq(pdev, 0); 767 if (irq <= 0) { 768 if (!irq) 769 irq = -ENXIO; 770 return dev_err_probe(&pdev->dev, irq, "can't get irq resource\n"); 771 } 772 773 dev = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_dev), 774 GFP_KERNEL); 775 if (!dev) { 776 dev_err(&pdev->dev, "Memory allocation failed\n"); 777 return -ENOMEM; 778 } 779 780 init_completion(&dev->cmd_complete); 781 782 dev->dev = &pdev->dev; 783 dev->irq = irq; 784 dev->pdata = dev_get_platdata(&pdev->dev); 785 platform_set_drvdata(pdev, dev); 786 787 if (!dev->pdata && pdev->dev.of_node) { 788 u32 prop; 789 790 dev->pdata = devm_kzalloc(&pdev->dev, 791 sizeof(struct davinci_i2c_platform_data), GFP_KERNEL); 792 if (!dev->pdata) 793 return -ENOMEM; 794 795 memcpy(dev->pdata, &davinci_i2c_platform_data_default, 796 sizeof(struct davinci_i2c_platform_data)); 797 if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency", 798 &prop)) 799 dev->pdata->bus_freq = prop / 1000; 800 801 dev->pdata->has_pfunc = 802 of_property_read_bool(pdev->dev.of_node, 803 "ti,has-pfunc"); 804 } else if (!dev->pdata) { 805 dev->pdata = &davinci_i2c_platform_data_default; 806 } 807 808 dev->clk = devm_clk_get(&pdev->dev, NULL); 809 if (IS_ERR(dev->clk)) 810 return PTR_ERR(dev->clk); 811 812 dev->base = devm_platform_ioremap_resource(pdev, 0); 813 if (IS_ERR(dev->base)) { 814 return PTR_ERR(dev->base); 815 } 816 817 pm_runtime_set_autosuspend_delay(dev->dev, 818 DAVINCI_I2C_PM_TIMEOUT); 819 pm_runtime_use_autosuspend(dev->dev); 820 821 pm_runtime_enable(dev->dev); 822 823 r = pm_runtime_resume_and_get(dev->dev); 824 if (r < 0) { 825 dev_err(dev->dev, "failed to runtime_get device: %d\n", r); 826 goto err_pm; 827 } 828 829 i2c_davinci_init(dev); 830 831 r = devm_request_irq(&pdev->dev, dev->irq, i2c_davinci_isr, 0, 832 pdev->name, dev); 833 if (r) { 834 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq); 835 goto err_unuse_clocks; 836 } 837 838 r = i2c_davinci_cpufreq_register(dev); 839 if (r) { 840 dev_err(&pdev->dev, "failed to register cpufreq\n"); 841 goto err_unuse_clocks; 842 } 843 844 adap = &dev->adapter; 845 i2c_set_adapdata(adap, dev); 846 adap->owner = THIS_MODULE; 847 adap->class = I2C_CLASS_DEPRECATED; 848 strscpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name)); 849 adap->algo = &i2c_davinci_algo; 850 adap->dev.parent = &pdev->dev; 851 adap->timeout = DAVINCI_I2C_TIMEOUT; 852 adap->dev.of_node = pdev->dev.of_node; 853 854 if (dev->pdata->has_pfunc) 855 adap->bus_recovery_info = &davinci_i2c_scl_recovery_info; 856 else if (dev->pdata->gpio_recovery) { 857 rinfo = &davinci_i2c_gpio_recovery_info; 858 adap->bus_recovery_info = rinfo; 859 rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", 860 GPIOD_OUT_HIGH_OPEN_DRAIN); 861 if (IS_ERR(rinfo->scl_gpiod)) { 862 r = PTR_ERR(rinfo->scl_gpiod); 863 goto err_unuse_clocks; 864 } 865 rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN); 866 if (IS_ERR(rinfo->sda_gpiod)) { 867 r = PTR_ERR(rinfo->sda_gpiod); 868 goto err_unuse_clocks; 869 } 870 } 871 872 adap->nr = pdev->id; 873 r = i2c_add_numbered_adapter(adap); 874 if (r) 875 goto err_unuse_clocks; 876 877 pm_runtime_mark_last_busy(dev->dev); 878 pm_runtime_put_autosuspend(dev->dev); 879 880 return 0; 881 882 err_unuse_clocks: 883 pm_runtime_dont_use_autosuspend(dev->dev); 884 pm_runtime_put_sync(dev->dev); 885 err_pm: 886 pm_runtime_disable(dev->dev); 887 888 return r; 889 } 890 891 static int davinci_i2c_remove(struct platform_device *pdev) 892 { 893 struct davinci_i2c_dev *dev = platform_get_drvdata(pdev); 894 int ret; 895 896 i2c_davinci_cpufreq_deregister(dev); 897 898 i2c_del_adapter(&dev->adapter); 899 900 ret = pm_runtime_resume_and_get(&pdev->dev); 901 if (ret < 0) 902 return ret; 903 904 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0); 905 906 pm_runtime_dont_use_autosuspend(dev->dev); 907 pm_runtime_put_sync(dev->dev); 908 pm_runtime_disable(dev->dev); 909 910 return 0; 911 } 912 913 #ifdef CONFIG_PM 914 static int davinci_i2c_suspend(struct device *dev) 915 { 916 struct davinci_i2c_dev *i2c_dev = dev_get_drvdata(dev); 917 918 /* put I2C into reset */ 919 davinci_i2c_reset_ctrl(i2c_dev, 0); 920 921 return 0; 922 } 923 924 static int davinci_i2c_resume(struct device *dev) 925 { 926 struct davinci_i2c_dev *i2c_dev = dev_get_drvdata(dev); 927 928 /* take I2C out of reset */ 929 davinci_i2c_reset_ctrl(i2c_dev, 1); 930 931 return 0; 932 } 933 934 static const struct dev_pm_ops davinci_i2c_pm = { 935 .suspend = davinci_i2c_suspend, 936 .resume = davinci_i2c_resume, 937 SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, 938 pm_runtime_force_resume) 939 }; 940 941 #define davinci_i2c_pm_ops (&davinci_i2c_pm) 942 #else 943 #define davinci_i2c_pm_ops NULL 944 #endif 945 946 /* work with hotplug and coldplug */ 947 MODULE_ALIAS("platform:i2c_davinci"); 948 949 static struct platform_driver davinci_i2c_driver = { 950 .probe = davinci_i2c_probe, 951 .remove = davinci_i2c_remove, 952 .driver = { 953 .name = "i2c_davinci", 954 .pm = davinci_i2c_pm_ops, 955 .of_match_table = davinci_i2c_of_match, 956 }, 957 }; 958 959 /* I2C may be needed to bring up other drivers */ 960 static int __init davinci_i2c_init_driver(void) 961 { 962 return platform_driver_register(&davinci_i2c_driver); 963 } 964 subsys_initcall(davinci_i2c_init_driver); 965 966 static void __exit davinci_i2c_exit_driver(void) 967 { 968 platform_driver_unregister(&davinci_i2c_driver); 969 } 970 module_exit(davinci_i2c_exit_driver); 971 972 MODULE_AUTHOR("Texas Instruments India"); 973 MODULE_DESCRIPTION("TI DaVinci I2C bus adapter"); 974 MODULE_LICENSE("GPL"); 975