1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * i2c-exynos5.c - Samsung Exynos5 I2C Controller Driver 4 * 5 * Copyright (C) 2013 Samsung Electronics Co., Ltd. 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 11 #include <linux/i2c.h> 12 #include <linux/time.h> 13 #include <linux/interrupt.h> 14 #include <linux/delay.h> 15 #include <linux/errno.h> 16 #include <linux/err.h> 17 #include <linux/platform_device.h> 18 #include <linux/clk.h> 19 #include <linux/slab.h> 20 #include <linux/io.h> 21 #include <linux/of.h> 22 #include <linux/spinlock.h> 23 24 /* 25 * HSI2C controller from Samsung supports 2 modes of operation 26 * 1. Auto mode: Where in master automatically controls the whole transaction 27 * 2. Manual mode: Software controls the transaction by issuing commands 28 * START, READ, WRITE, STOP, RESTART in I2C_MANUAL_CMD register. 29 * 30 * Operation mode can be selected by setting AUTO_MODE bit in I2C_CONF register 31 * 32 * Special bits are available for both modes of operation to set commands 33 * and for checking transfer status 34 */ 35 36 /* Register Map */ 37 #define HSI2C_CTL 0x00 38 #define HSI2C_FIFO_CTL 0x04 39 #define HSI2C_TRAILIG_CTL 0x08 40 #define HSI2C_CLK_CTL 0x0C 41 #define HSI2C_CLK_SLOT 0x10 42 #define HSI2C_INT_ENABLE 0x20 43 #define HSI2C_INT_STATUS 0x24 44 #define HSI2C_ERR_STATUS 0x2C 45 #define HSI2C_FIFO_STATUS 0x30 46 #define HSI2C_TX_DATA 0x34 47 #define HSI2C_RX_DATA 0x38 48 #define HSI2C_CONF 0x40 49 #define HSI2C_AUTO_CONF 0x44 50 #define HSI2C_TIMEOUT 0x48 51 #define HSI2C_MANUAL_CMD 0x4C 52 #define HSI2C_TRANS_STATUS 0x50 53 #define HSI2C_TIMING_HS1 0x54 54 #define HSI2C_TIMING_HS2 0x58 55 #define HSI2C_TIMING_HS3 0x5C 56 #define HSI2C_TIMING_FS1 0x60 57 #define HSI2C_TIMING_FS2 0x64 58 #define HSI2C_TIMING_FS3 0x68 59 #define HSI2C_TIMING_SLA 0x6C 60 #define HSI2C_ADDR 0x70 61 62 /* I2C_CTL Register bits */ 63 #define HSI2C_FUNC_MODE_I2C (1u << 0) 64 #define HSI2C_MASTER (1u << 3) 65 #define HSI2C_RXCHON (1u << 6) 66 #define HSI2C_TXCHON (1u << 7) 67 #define HSI2C_SW_RST (1u << 31) 68 69 /* I2C_FIFO_CTL Register bits */ 70 #define HSI2C_RXFIFO_EN (1u << 0) 71 #define HSI2C_TXFIFO_EN (1u << 1) 72 #define HSI2C_RXFIFO_TRIGGER_LEVEL(x) ((x) << 4) 73 #define HSI2C_TXFIFO_TRIGGER_LEVEL(x) ((x) << 16) 74 75 /* I2C_TRAILING_CTL Register bits */ 76 #define HSI2C_TRAILING_COUNT (0xf) 77 78 /* I2C_INT_EN Register bits */ 79 #define HSI2C_INT_TX_ALMOSTEMPTY_EN (1u << 0) 80 #define HSI2C_INT_RX_ALMOSTFULL_EN (1u << 1) 81 #define HSI2C_INT_TRAILING_EN (1u << 6) 82 83 /* I2C_INT_STAT Register bits */ 84 #define HSI2C_INT_TX_ALMOSTEMPTY (1u << 0) 85 #define HSI2C_INT_RX_ALMOSTFULL (1u << 1) 86 #define HSI2C_INT_TX_UNDERRUN (1u << 2) 87 #define HSI2C_INT_TX_OVERRUN (1u << 3) 88 #define HSI2C_INT_RX_UNDERRUN (1u << 4) 89 #define HSI2C_INT_RX_OVERRUN (1u << 5) 90 #define HSI2C_INT_TRAILING (1u << 6) 91 #define HSI2C_INT_I2C (1u << 9) 92 93 #define HSI2C_INT_TRANS_DONE (1u << 7) 94 #define HSI2C_INT_TRANS_ABORT (1u << 8) 95 #define HSI2C_INT_NO_DEV_ACK (1u << 9) 96 #define HSI2C_INT_NO_DEV (1u << 10) 97 #define HSI2C_INT_TIMEOUT (1u << 11) 98 #define HSI2C_INT_I2C_TRANS (HSI2C_INT_TRANS_DONE | \ 99 HSI2C_INT_TRANS_ABORT | \ 100 HSI2C_INT_NO_DEV_ACK | \ 101 HSI2C_INT_NO_DEV | \ 102 HSI2C_INT_TIMEOUT) 103 104 /* I2C_FIFO_STAT Register bits */ 105 #define HSI2C_RX_FIFO_EMPTY (1u << 24) 106 #define HSI2C_RX_FIFO_FULL (1u << 23) 107 #define HSI2C_RX_FIFO_LVL(x) ((x >> 16) & 0x7f) 108 #define HSI2C_TX_FIFO_EMPTY (1u << 8) 109 #define HSI2C_TX_FIFO_FULL (1u << 7) 110 #define HSI2C_TX_FIFO_LVL(x) ((x >> 0) & 0x7f) 111 112 /* I2C_CONF Register bits */ 113 #define HSI2C_AUTO_MODE (1u << 31) 114 #define HSI2C_10BIT_ADDR_MODE (1u << 30) 115 #define HSI2C_HS_MODE (1u << 29) 116 117 /* I2C_AUTO_CONF Register bits */ 118 #define HSI2C_READ_WRITE (1u << 16) 119 #define HSI2C_STOP_AFTER_TRANS (1u << 17) 120 #define HSI2C_MASTER_RUN (1u << 31) 121 122 /* I2C_TIMEOUT Register bits */ 123 #define HSI2C_TIMEOUT_EN (1u << 31) 124 #define HSI2C_TIMEOUT_MASK 0xff 125 126 /* I2C_MANUAL_CMD register bits */ 127 #define HSI2C_CMD_READ_DATA (1u << 4) 128 #define HSI2C_CMD_SEND_STOP (1u << 2) 129 130 /* I2C_TRANS_STATUS register bits */ 131 #define HSI2C_MASTER_BUSY (1u << 17) 132 #define HSI2C_SLAVE_BUSY (1u << 16) 133 134 /* I2C_TRANS_STATUS register bits for Exynos5 variant */ 135 #define HSI2C_TIMEOUT_AUTO (1u << 4) 136 #define HSI2C_NO_DEV (1u << 3) 137 #define HSI2C_NO_DEV_ACK (1u << 2) 138 #define HSI2C_TRANS_ABORT (1u << 1) 139 #define HSI2C_TRANS_DONE (1u << 0) 140 141 /* I2C_TRANS_STATUS register bits for Exynos7 variant */ 142 #define HSI2C_MASTER_ST_MASK 0xf 143 #define HSI2C_MASTER_ST_IDLE 0x0 144 #define HSI2C_MASTER_ST_START 0x1 145 #define HSI2C_MASTER_ST_RESTART 0x2 146 #define HSI2C_MASTER_ST_STOP 0x3 147 #define HSI2C_MASTER_ST_MASTER_ID 0x4 148 #define HSI2C_MASTER_ST_ADDR0 0x5 149 #define HSI2C_MASTER_ST_ADDR1 0x6 150 #define HSI2C_MASTER_ST_ADDR2 0x7 151 #define HSI2C_MASTER_ST_ADDR_SR 0x8 152 #define HSI2C_MASTER_ST_READ 0x9 153 #define HSI2C_MASTER_ST_WRITE 0xa 154 #define HSI2C_MASTER_ST_NO_ACK 0xb 155 #define HSI2C_MASTER_ST_LOSE 0xc 156 #define HSI2C_MASTER_ST_WAIT 0xd 157 #define HSI2C_MASTER_ST_WAIT_CMD 0xe 158 159 /* I2C_ADDR register bits */ 160 #define HSI2C_SLV_ADDR_SLV(x) ((x & 0x3ff) << 0) 161 #define HSI2C_SLV_ADDR_MAS(x) ((x & 0x3ff) << 10) 162 #define HSI2C_MASTER_ID(x) ((x & 0xff) << 24) 163 #define MASTER_ID(x) ((x & 0x7) + 0x08) 164 165 #define EXYNOS5_I2C_TIMEOUT (msecs_to_jiffies(100)) 166 167 enum i2c_type_exynos { 168 I2C_TYPE_EXYNOS5, 169 I2C_TYPE_EXYNOS7, 170 I2C_TYPE_EXYNOSAUTOV9, 171 }; 172 173 struct exynos5_i2c { 174 struct i2c_adapter adap; 175 176 struct i2c_msg *msg; 177 struct completion msg_complete; 178 unsigned int msg_ptr; 179 180 unsigned int irq; 181 182 void __iomem *regs; 183 struct clk *clk; /* operating clock */ 184 struct clk *pclk; /* bus clock */ 185 struct device *dev; 186 int state; 187 188 spinlock_t lock; /* IRQ synchronization */ 189 190 /* 191 * Since the TRANS_DONE bit is cleared on read, and we may read it 192 * either during an IRQ or after a transaction, keep track of its 193 * state here. 194 */ 195 int trans_done; 196 197 /* 198 * Called from atomic context, don't use interrupts. 199 */ 200 unsigned int atomic; 201 202 /* Controller operating frequency */ 203 unsigned int op_clock; 204 205 /* Version of HS-I2C Hardware */ 206 const struct exynos_hsi2c_variant *variant; 207 }; 208 209 /** 210 * struct exynos_hsi2c_variant - platform specific HSI2C driver data 211 * @fifo_depth: the fifo depth supported by the HSI2C module 212 * @hw: the hardware variant of Exynos I2C controller 213 * 214 * Specifies platform specific configuration of HSI2C module. 215 * Note: A structure for driver specific platform data is used for future 216 * expansion of its usage. 217 */ 218 struct exynos_hsi2c_variant { 219 unsigned int fifo_depth; 220 enum i2c_type_exynos hw; 221 }; 222 223 static const struct exynos_hsi2c_variant exynos5250_hsi2c_data = { 224 .fifo_depth = 64, 225 .hw = I2C_TYPE_EXYNOS5, 226 }; 227 228 static const struct exynos_hsi2c_variant exynos5260_hsi2c_data = { 229 .fifo_depth = 16, 230 .hw = I2C_TYPE_EXYNOS5, 231 }; 232 233 static const struct exynos_hsi2c_variant exynos7_hsi2c_data = { 234 .fifo_depth = 16, 235 .hw = I2C_TYPE_EXYNOS7, 236 }; 237 238 static const struct exynos_hsi2c_variant exynosautov9_hsi2c_data = { 239 .fifo_depth = 64, 240 .hw = I2C_TYPE_EXYNOSAUTOV9, 241 }; 242 243 static const struct of_device_id exynos5_i2c_match[] = { 244 { 245 .compatible = "samsung,exynos5-hsi2c", 246 .data = &exynos5250_hsi2c_data 247 }, { 248 .compatible = "samsung,exynos5250-hsi2c", 249 .data = &exynos5250_hsi2c_data 250 }, { 251 .compatible = "samsung,exynos5260-hsi2c", 252 .data = &exynos5260_hsi2c_data 253 }, { 254 .compatible = "samsung,exynos7-hsi2c", 255 .data = &exynos7_hsi2c_data 256 }, { 257 .compatible = "samsung,exynosautov9-hsi2c", 258 .data = &exynosautov9_hsi2c_data 259 }, {}, 260 }; 261 MODULE_DEVICE_TABLE(of, exynos5_i2c_match); 262 263 static void exynos5_i2c_clr_pend_irq(struct exynos5_i2c *i2c) 264 { 265 writel(readl(i2c->regs + HSI2C_INT_STATUS), 266 i2c->regs + HSI2C_INT_STATUS); 267 } 268 269 /* 270 * exynos5_i2c_set_timing: updates the registers with appropriate 271 * timing values calculated 272 * 273 * Timing values for operation are calculated against 100kHz, 400kHz 274 * or 1MHz controller operating frequency. 275 * 276 * Returns 0 on success, -EINVAL if the cycle length cannot 277 * be calculated. 278 */ 279 static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings) 280 { 281 u32 i2c_timing_s1; 282 u32 i2c_timing_s2; 283 u32 i2c_timing_s3; 284 u32 i2c_timing_sla; 285 unsigned int t_start_su, t_start_hd; 286 unsigned int t_stop_su; 287 unsigned int t_data_su, t_data_hd; 288 unsigned int t_scl_l, t_scl_h; 289 unsigned int t_sr_release; 290 unsigned int t_ftl_cycle; 291 unsigned int clkin = clk_get_rate(i2c->clk); 292 unsigned int op_clk = hs_timings ? i2c->op_clock : 293 (i2c->op_clock >= I2C_MAX_FAST_MODE_PLUS_FREQ) ? I2C_MAX_STANDARD_MODE_FREQ : 294 i2c->op_clock; 295 int div, clk_cycle, temp; 296 297 /* 298 * In case of HSI2C controllers in ExynosAutoV9: 299 * 300 * FSCL = IPCLK / ((CLK_DIV + 1) * 16) 301 * T_SCL_LOW = IPCLK * (CLK_DIV + 1) * (N + M) 302 * [N : number of 0's in the TSCL_H_HS] 303 * [M : number of 0's in the TSCL_L_HS] 304 * T_SCL_HIGH = IPCLK * (CLK_DIV + 1) * (N + M) 305 * [N : number of 1's in the TSCL_H_HS] 306 * [M : number of 1's in the TSCL_L_HS] 307 * 308 * Result of (N + M) is always 8. 309 * In general case, we don't need to control timing_s1 and timing_s2. 310 */ 311 if (i2c->variant->hw == I2C_TYPE_EXYNOSAUTOV9) { 312 div = ((clkin / (16 * i2c->op_clock)) - 1); 313 i2c_timing_s3 = div << 16; 314 if (hs_timings) 315 writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_HS3); 316 else 317 writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_FS3); 318 319 return 0; 320 } 321 322 /* 323 * In case of HSI2C controller in Exynos5 series 324 * FPCLK / FI2C = 325 * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE 326 * 327 * In case of HSI2C controllers in Exynos7 series 328 * FPCLK / FI2C = 329 * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + FLT_CYCLE 330 * 331 * clk_cycle := TSCLK_L + TSCLK_H 332 * temp := (CLK_DIV + 1) * (clk_cycle + 2) 333 * 334 * Constraints: 4 <= temp, 0 <= CLK_DIV < 256, 2 <= clk_cycle <= 510 335 * 336 * To split SCL clock into low, high periods appropriately, one 337 * proportion factor for each I2C mode is used, which is calculated 338 * using this formula. 339 * ``` 340 * ((t_low_min + (scl_clock - t_low_min - t_high_min) / 2) / scl_clock) 341 * ``` 342 * where: 343 * t_low_min is the minimal value of low period of the SCL clock in us; 344 * t_high_min is the minimal value of high period of the SCL clock in us; 345 * scl_clock is converted from SCL clock frequency into us. 346 * 347 * Below are the proportion factors for these I2C modes: 348 * t_low_min, t_high_min, scl_clock, proportion 349 * Standard Mode: 4.7us, 4.0us, 10us, 0.535 350 * Fast Mode: 1.3us, 0.6us, 2.5us, 0.64 351 * Fast-Plus Mode: 0.5us, 0.26us, 1us, 0.62 352 * 353 */ 354 t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7; 355 temp = clkin / op_clk - 8 - t_ftl_cycle; 356 if (i2c->variant->hw != I2C_TYPE_EXYNOS7) 357 temp -= t_ftl_cycle; 358 div = temp / 512; 359 clk_cycle = temp / (div + 1) - 2; 360 if (temp < 4 || div >= 256 || clk_cycle < 2) { 361 dev_err(i2c->dev, "%s clock set-up failed\n", 362 hs_timings ? "HS" : "FS"); 363 return -EINVAL; 364 } 365 366 /* 367 * Scale clk_cycle to get t_scl_l using the proption factors for individual I2C modes. 368 */ 369 if (op_clk <= I2C_MAX_STANDARD_MODE_FREQ) 370 t_scl_l = clk_cycle * 535 / 1000; 371 else if (op_clk <= I2C_MAX_FAST_MODE_FREQ) 372 t_scl_l = clk_cycle * 64 / 100; 373 else 374 t_scl_l = clk_cycle * 62 / 100; 375 376 if (t_scl_l > 0xFF) 377 t_scl_l = 0xFF; 378 t_scl_h = clk_cycle - t_scl_l; 379 t_start_su = t_scl_l; 380 t_start_hd = t_scl_l; 381 t_stop_su = t_scl_l; 382 t_data_su = t_scl_l / 2; 383 t_data_hd = t_scl_l / 2; 384 t_sr_release = clk_cycle; 385 386 i2c_timing_s1 = t_start_su << 24 | t_start_hd << 16 | t_stop_su << 8; 387 i2c_timing_s2 = t_data_su << 24 | t_scl_l << 8 | t_scl_h << 0; 388 i2c_timing_s3 = div << 16 | t_sr_release << 0; 389 i2c_timing_sla = t_data_hd << 0; 390 391 dev_dbg(i2c->dev, "tSTART_SU: %X, tSTART_HD: %X, tSTOP_SU: %X\n", 392 t_start_su, t_start_hd, t_stop_su); 393 dev_dbg(i2c->dev, "tDATA_SU: %X, tSCL_L: %X, tSCL_H: %X\n", 394 t_data_su, t_scl_l, t_scl_h); 395 dev_dbg(i2c->dev, "nClkDiv: %X, tSR_RELEASE: %X\n", 396 div, t_sr_release); 397 dev_dbg(i2c->dev, "tDATA_HD: %X\n", t_data_hd); 398 399 if (hs_timings) { 400 writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_HS1); 401 writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_HS2); 402 writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_HS3); 403 } else { 404 writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_FS1); 405 writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_FS2); 406 writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_FS3); 407 } 408 writel(i2c_timing_sla, i2c->regs + HSI2C_TIMING_SLA); 409 410 return 0; 411 } 412 413 static int exynos5_hsi2c_clock_setup(struct exynos5_i2c *i2c) 414 { 415 /* always set Fast Speed timings */ 416 int ret = exynos5_i2c_set_timing(i2c, false); 417 418 if (ret < 0 || i2c->op_clock < I2C_MAX_FAST_MODE_PLUS_FREQ) 419 return ret; 420 421 return exynos5_i2c_set_timing(i2c, true); 422 } 423 424 /* 425 * exynos5_i2c_init: configures the controller for I2C functionality 426 * Programs I2C controller for Master mode operation 427 */ 428 static void exynos5_i2c_init(struct exynos5_i2c *i2c) 429 { 430 u32 i2c_conf = readl(i2c->regs + HSI2C_CONF); 431 u32 i2c_timeout = readl(i2c->regs + HSI2C_TIMEOUT); 432 433 /* Clear to disable Timeout */ 434 i2c_timeout &= ~HSI2C_TIMEOUT_EN; 435 writel(i2c_timeout, i2c->regs + HSI2C_TIMEOUT); 436 437 writel((HSI2C_FUNC_MODE_I2C | HSI2C_MASTER), 438 i2c->regs + HSI2C_CTL); 439 writel(HSI2C_TRAILING_COUNT, i2c->regs + HSI2C_TRAILIG_CTL); 440 441 if (i2c->op_clock >= I2C_MAX_FAST_MODE_PLUS_FREQ) { 442 writel(HSI2C_MASTER_ID(MASTER_ID(i2c->adap.nr)), 443 i2c->regs + HSI2C_ADDR); 444 i2c_conf |= HSI2C_HS_MODE; 445 } 446 447 writel(i2c_conf | HSI2C_AUTO_MODE, i2c->regs + HSI2C_CONF); 448 } 449 450 static void exynos5_i2c_reset(struct exynos5_i2c *i2c) 451 { 452 u32 i2c_ctl; 453 454 /* Set and clear the bit for reset */ 455 i2c_ctl = readl(i2c->regs + HSI2C_CTL); 456 i2c_ctl |= HSI2C_SW_RST; 457 writel(i2c_ctl, i2c->regs + HSI2C_CTL); 458 459 i2c_ctl = readl(i2c->regs + HSI2C_CTL); 460 i2c_ctl &= ~HSI2C_SW_RST; 461 writel(i2c_ctl, i2c->regs + HSI2C_CTL); 462 463 /* We don't expect calculations to fail during the run */ 464 exynos5_hsi2c_clock_setup(i2c); 465 /* Initialize the configure registers */ 466 exynos5_i2c_init(i2c); 467 } 468 469 /* 470 * exynos5_i2c_irq: top level IRQ servicing routine 471 * 472 * INT_STATUS registers gives the interrupt details. Further, 473 * FIFO_STATUS or TRANS_STATUS registers are to be check for detailed 474 * state of the bus. 475 */ 476 static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id) 477 { 478 struct exynos5_i2c *i2c = dev_id; 479 u32 fifo_level, int_status, fifo_status, trans_status; 480 unsigned char byte; 481 int len = 0; 482 483 i2c->state = -EINVAL; 484 485 spin_lock(&i2c->lock); 486 487 int_status = readl(i2c->regs + HSI2C_INT_STATUS); 488 writel(int_status, i2c->regs + HSI2C_INT_STATUS); 489 490 /* handle interrupt related to the transfer status */ 491 switch (i2c->variant->hw) { 492 case I2C_TYPE_EXYNOSAUTOV9: 493 fallthrough; 494 case I2C_TYPE_EXYNOS7: 495 if (int_status & HSI2C_INT_TRANS_DONE) { 496 i2c->trans_done = 1; 497 i2c->state = 0; 498 } else if (int_status & HSI2C_INT_TRANS_ABORT) { 499 dev_dbg(i2c->dev, "Deal with arbitration lose\n"); 500 i2c->state = -EAGAIN; 501 goto stop; 502 } else if (int_status & HSI2C_INT_NO_DEV_ACK) { 503 dev_dbg(i2c->dev, "No ACK from device\n"); 504 i2c->state = -ENXIO; 505 goto stop; 506 } else if (int_status & HSI2C_INT_NO_DEV) { 507 dev_dbg(i2c->dev, "No device\n"); 508 i2c->state = -ENXIO; 509 goto stop; 510 } else if (int_status & HSI2C_INT_TIMEOUT) { 511 dev_dbg(i2c->dev, "Accessing device timed out\n"); 512 i2c->state = -ETIMEDOUT; 513 goto stop; 514 } 515 516 break; 517 case I2C_TYPE_EXYNOS5: 518 if (!(int_status & HSI2C_INT_I2C)) 519 break; 520 521 trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS); 522 if (trans_status & HSI2C_NO_DEV_ACK) { 523 dev_dbg(i2c->dev, "No ACK from device\n"); 524 i2c->state = -ENXIO; 525 goto stop; 526 } else if (trans_status & HSI2C_NO_DEV) { 527 dev_dbg(i2c->dev, "No device\n"); 528 i2c->state = -ENXIO; 529 goto stop; 530 } else if (trans_status & HSI2C_TRANS_ABORT) { 531 dev_dbg(i2c->dev, "Deal with arbitration lose\n"); 532 i2c->state = -EAGAIN; 533 goto stop; 534 } else if (trans_status & HSI2C_TIMEOUT_AUTO) { 535 dev_dbg(i2c->dev, "Accessing device timed out\n"); 536 i2c->state = -ETIMEDOUT; 537 goto stop; 538 } else if (trans_status & HSI2C_TRANS_DONE) { 539 i2c->trans_done = 1; 540 i2c->state = 0; 541 } 542 543 break; 544 } 545 546 if ((i2c->msg->flags & I2C_M_RD) && (int_status & 547 (HSI2C_INT_TRAILING | HSI2C_INT_RX_ALMOSTFULL))) { 548 fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS); 549 fifo_level = HSI2C_RX_FIFO_LVL(fifo_status); 550 len = min(fifo_level, i2c->msg->len - i2c->msg_ptr); 551 552 while (len > 0) { 553 byte = (unsigned char) 554 readl(i2c->regs + HSI2C_RX_DATA); 555 i2c->msg->buf[i2c->msg_ptr++] = byte; 556 len--; 557 } 558 i2c->state = 0; 559 } else if (int_status & HSI2C_INT_TX_ALMOSTEMPTY) { 560 fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS); 561 fifo_level = HSI2C_TX_FIFO_LVL(fifo_status); 562 563 len = i2c->variant->fifo_depth - fifo_level; 564 if (len > (i2c->msg->len - i2c->msg_ptr)) { 565 u32 int_en = readl(i2c->regs + HSI2C_INT_ENABLE); 566 567 int_en &= ~HSI2C_INT_TX_ALMOSTEMPTY_EN; 568 writel(int_en, i2c->regs + HSI2C_INT_ENABLE); 569 len = i2c->msg->len - i2c->msg_ptr; 570 } 571 572 while (len > 0) { 573 byte = i2c->msg->buf[i2c->msg_ptr++]; 574 writel(byte, i2c->regs + HSI2C_TX_DATA); 575 len--; 576 } 577 i2c->state = 0; 578 } 579 580 stop: 581 if ((i2c->trans_done && (i2c->msg->len == i2c->msg_ptr)) || 582 (i2c->state < 0)) { 583 writel(0, i2c->regs + HSI2C_INT_ENABLE); 584 exynos5_i2c_clr_pend_irq(i2c); 585 complete(&i2c->msg_complete); 586 } 587 588 spin_unlock(&i2c->lock); 589 590 return IRQ_HANDLED; 591 } 592 593 /* 594 * exynos5_i2c_wait_bus_idle 595 * 596 * Wait for the bus to go idle, indicated by the MASTER_BUSY bit being 597 * cleared. 598 * 599 * Returns -EBUSY if the bus cannot be bought to idle 600 */ 601 static int exynos5_i2c_wait_bus_idle(struct exynos5_i2c *i2c) 602 { 603 unsigned long stop_time; 604 u32 trans_status; 605 606 /* wait for 100 milli seconds for the bus to be idle */ 607 stop_time = jiffies + msecs_to_jiffies(100) + 1; 608 do { 609 trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS); 610 if (!(trans_status & HSI2C_MASTER_BUSY)) 611 return 0; 612 613 usleep_range(50, 200); 614 } while (time_before(jiffies, stop_time)); 615 616 return -EBUSY; 617 } 618 619 static void exynos5_i2c_bus_recover(struct exynos5_i2c *i2c) 620 { 621 u32 val; 622 623 val = readl(i2c->regs + HSI2C_CTL) | HSI2C_RXCHON; 624 writel(val, i2c->regs + HSI2C_CTL); 625 val = readl(i2c->regs + HSI2C_CONF) & ~HSI2C_AUTO_MODE; 626 writel(val, i2c->regs + HSI2C_CONF); 627 628 /* 629 * Specification says master should send nine clock pulses. It can be 630 * emulated by sending manual read command (nine pulses for read eight 631 * bits + one pulse for NACK). 632 */ 633 writel(HSI2C_CMD_READ_DATA, i2c->regs + HSI2C_MANUAL_CMD); 634 exynos5_i2c_wait_bus_idle(i2c); 635 writel(HSI2C_CMD_SEND_STOP, i2c->regs + HSI2C_MANUAL_CMD); 636 exynos5_i2c_wait_bus_idle(i2c); 637 638 val = readl(i2c->regs + HSI2C_CTL) & ~HSI2C_RXCHON; 639 writel(val, i2c->regs + HSI2C_CTL); 640 val = readl(i2c->regs + HSI2C_CONF) | HSI2C_AUTO_MODE; 641 writel(val, i2c->regs + HSI2C_CONF); 642 } 643 644 static void exynos5_i2c_bus_check(struct exynos5_i2c *i2c) 645 { 646 unsigned long timeout; 647 648 if (i2c->variant->hw == I2C_TYPE_EXYNOS5) 649 return; 650 651 /* 652 * HSI2C_MASTER_ST_LOSE state (in Exynos7 and ExynosAutoV9 variants) 653 * before transaction indicates that bus is stuck (SDA is low). 654 * In such case bus recovery can be performed. 655 */ 656 timeout = jiffies + msecs_to_jiffies(100); 657 for (;;) { 658 u32 st = readl(i2c->regs + HSI2C_TRANS_STATUS); 659 660 if ((st & HSI2C_MASTER_ST_MASK) != HSI2C_MASTER_ST_LOSE) 661 return; 662 663 if (time_is_before_jiffies(timeout)) 664 return; 665 666 exynos5_i2c_bus_recover(i2c); 667 } 668 } 669 670 /* 671 * exynos5_i2c_message_start: Configures the bus and starts the xfer 672 * i2c: struct exynos5_i2c pointer for the current bus 673 * stop: Enables stop after transfer if set. Set for last transfer of 674 * in the list of messages. 675 * 676 * Configures the bus for read/write function 677 * Sets chip address to talk to, message length to be sent. 678 * Enables appropriate interrupts and sends start xfer command. 679 */ 680 static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop) 681 { 682 u32 i2c_ctl; 683 u32 int_en = 0; 684 u32 i2c_auto_conf = 0; 685 u32 i2c_addr = 0; 686 u32 fifo_ctl; 687 unsigned long flags; 688 unsigned short trig_lvl; 689 690 if (i2c->variant->hw == I2C_TYPE_EXYNOS5) 691 int_en |= HSI2C_INT_I2C; 692 else 693 int_en |= HSI2C_INT_I2C_TRANS; 694 695 i2c_ctl = readl(i2c->regs + HSI2C_CTL); 696 i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON); 697 fifo_ctl = HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN; 698 699 if (i2c->msg->flags & I2C_M_RD) { 700 i2c_ctl |= HSI2C_RXCHON; 701 702 i2c_auto_conf |= HSI2C_READ_WRITE; 703 704 trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ? 705 (i2c->variant->fifo_depth * 3 / 4) : i2c->msg->len; 706 fifo_ctl |= HSI2C_RXFIFO_TRIGGER_LEVEL(trig_lvl); 707 708 int_en |= (HSI2C_INT_RX_ALMOSTFULL_EN | 709 HSI2C_INT_TRAILING_EN); 710 } else { 711 i2c_ctl |= HSI2C_TXCHON; 712 713 trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ? 714 (i2c->variant->fifo_depth * 1 / 4) : i2c->msg->len; 715 fifo_ctl |= HSI2C_TXFIFO_TRIGGER_LEVEL(trig_lvl); 716 717 int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN; 718 } 719 720 i2c_addr = HSI2C_SLV_ADDR_MAS(i2c->msg->addr); 721 722 if (i2c->op_clock >= I2C_MAX_FAST_MODE_PLUS_FREQ) 723 i2c_addr |= HSI2C_MASTER_ID(MASTER_ID(i2c->adap.nr)); 724 725 writel(i2c_addr, i2c->regs + HSI2C_ADDR); 726 727 writel(fifo_ctl, i2c->regs + HSI2C_FIFO_CTL); 728 writel(i2c_ctl, i2c->regs + HSI2C_CTL); 729 730 exynos5_i2c_bus_check(i2c); 731 732 /* 733 * Enable interrupts before starting the transfer so that we don't 734 * miss any INT_I2C interrupts. 735 */ 736 spin_lock_irqsave(&i2c->lock, flags); 737 writel(int_en, i2c->regs + HSI2C_INT_ENABLE); 738 739 if (stop == 1) 740 i2c_auto_conf |= HSI2C_STOP_AFTER_TRANS; 741 i2c_auto_conf |= i2c->msg->len; 742 i2c_auto_conf |= HSI2C_MASTER_RUN; 743 writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONF); 744 spin_unlock_irqrestore(&i2c->lock, flags); 745 } 746 747 static bool exynos5_i2c_poll_irqs_timeout(struct exynos5_i2c *i2c, 748 unsigned long timeout) 749 { 750 unsigned long time_left = jiffies + timeout; 751 752 while (time_before(jiffies, time_left) && 753 !((i2c->trans_done && (i2c->msg->len == i2c->msg_ptr)) || 754 (i2c->state < 0))) { 755 while (readl(i2c->regs + HSI2C_INT_ENABLE) & 756 readl(i2c->regs + HSI2C_INT_STATUS)) 757 exynos5_i2c_irq(i2c->irq, i2c); 758 usleep_range(100, 200); 759 } 760 return time_before(jiffies, time_left); 761 } 762 763 static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c, 764 struct i2c_msg *msgs, int stop) 765 { 766 unsigned long timeout; 767 int ret; 768 769 i2c->msg = msgs; 770 i2c->msg_ptr = 0; 771 i2c->trans_done = 0; 772 773 reinit_completion(&i2c->msg_complete); 774 775 exynos5_i2c_message_start(i2c, stop); 776 777 if (!i2c->atomic) 778 timeout = wait_for_completion_timeout(&i2c->msg_complete, 779 EXYNOS5_I2C_TIMEOUT); 780 else 781 timeout = exynos5_i2c_poll_irqs_timeout(i2c, 782 EXYNOS5_I2C_TIMEOUT); 783 784 if (timeout == 0) 785 ret = -ETIMEDOUT; 786 else 787 ret = i2c->state; 788 789 /* 790 * If this is the last message to be transfered (stop == 1) 791 * Then check if the bus can be brought back to idle. 792 */ 793 if (ret == 0 && stop) 794 ret = exynos5_i2c_wait_bus_idle(i2c); 795 796 if (ret < 0) { 797 exynos5_i2c_reset(i2c); 798 if (ret == -ETIMEDOUT) 799 dev_warn(i2c->dev, "%s timeout\n", 800 (msgs->flags & I2C_M_RD) ? "rx" : "tx"); 801 } 802 803 /* Return the state as in interrupt routine */ 804 return ret; 805 } 806 807 static int exynos5_i2c_xfer(struct i2c_adapter *adap, 808 struct i2c_msg *msgs, int num) 809 { 810 struct exynos5_i2c *i2c = adap->algo_data; 811 int i, ret; 812 813 ret = clk_enable(i2c->pclk); 814 if (ret) 815 return ret; 816 817 ret = clk_enable(i2c->clk); 818 if (ret) 819 goto err_pclk; 820 821 for (i = 0; i < num; ++i) { 822 ret = exynos5_i2c_xfer_msg(i2c, msgs + i, i + 1 == num); 823 if (ret) 824 break; 825 } 826 827 clk_disable(i2c->clk); 828 err_pclk: 829 clk_disable(i2c->pclk); 830 831 return ret ?: num; 832 } 833 834 static int exynos5_i2c_xfer_atomic(struct i2c_adapter *adap, 835 struct i2c_msg *msgs, int num) 836 { 837 struct exynos5_i2c *i2c = adap->algo_data; 838 int ret; 839 840 disable_irq(i2c->irq); 841 i2c->atomic = true; 842 ret = exynos5_i2c_xfer(adap, msgs, num); 843 i2c->atomic = false; 844 enable_irq(i2c->irq); 845 846 return ret; 847 } 848 849 static u32 exynos5_i2c_func(struct i2c_adapter *adap) 850 { 851 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); 852 } 853 854 static const struct i2c_algorithm exynos5_i2c_algorithm = { 855 .master_xfer = exynos5_i2c_xfer, 856 .master_xfer_atomic = exynos5_i2c_xfer_atomic, 857 .functionality = exynos5_i2c_func, 858 }; 859 860 static int exynos5_i2c_probe(struct platform_device *pdev) 861 { 862 struct device_node *np = pdev->dev.of_node; 863 struct exynos5_i2c *i2c; 864 int ret; 865 866 i2c = devm_kzalloc(&pdev->dev, sizeof(struct exynos5_i2c), GFP_KERNEL); 867 if (!i2c) 868 return -ENOMEM; 869 870 if (of_property_read_u32(np, "clock-frequency", &i2c->op_clock)) 871 i2c->op_clock = I2C_MAX_STANDARD_MODE_FREQ; 872 873 strscpy(i2c->adap.name, "exynos5-i2c", sizeof(i2c->adap.name)); 874 i2c->adap.owner = THIS_MODULE; 875 i2c->adap.algo = &exynos5_i2c_algorithm; 876 i2c->adap.retries = 3; 877 878 i2c->dev = &pdev->dev; 879 i2c->clk = devm_clk_get(&pdev->dev, "hsi2c"); 880 if (IS_ERR(i2c->clk)) { 881 dev_err(&pdev->dev, "cannot get clock\n"); 882 return -ENOENT; 883 } 884 885 i2c->pclk = devm_clk_get_optional(&pdev->dev, "hsi2c_pclk"); 886 if (IS_ERR(i2c->pclk)) { 887 return dev_err_probe(&pdev->dev, PTR_ERR(i2c->pclk), 888 "cannot get pclk"); 889 } 890 891 ret = clk_prepare_enable(i2c->pclk); 892 if (ret) 893 return ret; 894 895 ret = clk_prepare_enable(i2c->clk); 896 if (ret) 897 goto err_pclk; 898 899 i2c->regs = devm_platform_ioremap_resource(pdev, 0); 900 if (IS_ERR(i2c->regs)) { 901 ret = PTR_ERR(i2c->regs); 902 goto err_clk; 903 } 904 905 i2c->adap.dev.of_node = np; 906 i2c->adap.algo_data = i2c; 907 i2c->adap.dev.parent = &pdev->dev; 908 909 /* Clear pending interrupts from u-boot or misc causes */ 910 exynos5_i2c_clr_pend_irq(i2c); 911 912 spin_lock_init(&i2c->lock); 913 init_completion(&i2c->msg_complete); 914 915 i2c->irq = ret = platform_get_irq(pdev, 0); 916 if (ret < 0) 917 goto err_clk; 918 919 ret = devm_request_irq(&pdev->dev, i2c->irq, exynos5_i2c_irq, 920 IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c); 921 if (ret != 0) { 922 dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", i2c->irq); 923 goto err_clk; 924 } 925 926 i2c->variant = of_device_get_match_data(&pdev->dev); 927 928 ret = exynos5_hsi2c_clock_setup(i2c); 929 if (ret) 930 goto err_clk; 931 932 exynos5_i2c_reset(i2c); 933 934 ret = i2c_add_adapter(&i2c->adap); 935 if (ret < 0) 936 goto err_clk; 937 938 platform_set_drvdata(pdev, i2c); 939 940 clk_disable(i2c->clk); 941 clk_disable(i2c->pclk); 942 943 return 0; 944 945 err_clk: 946 clk_disable_unprepare(i2c->clk); 947 948 err_pclk: 949 clk_disable_unprepare(i2c->pclk); 950 return ret; 951 } 952 953 static void exynos5_i2c_remove(struct platform_device *pdev) 954 { 955 struct exynos5_i2c *i2c = platform_get_drvdata(pdev); 956 957 i2c_del_adapter(&i2c->adap); 958 959 clk_unprepare(i2c->clk); 960 clk_unprepare(i2c->pclk); 961 } 962 963 static int exynos5_i2c_suspend_noirq(struct device *dev) 964 { 965 struct exynos5_i2c *i2c = dev_get_drvdata(dev); 966 967 i2c_mark_adapter_suspended(&i2c->adap); 968 clk_unprepare(i2c->clk); 969 clk_unprepare(i2c->pclk); 970 971 return 0; 972 } 973 974 static int exynos5_i2c_resume_noirq(struct device *dev) 975 { 976 struct exynos5_i2c *i2c = dev_get_drvdata(dev); 977 int ret = 0; 978 979 ret = clk_prepare_enable(i2c->pclk); 980 if (ret) 981 return ret; 982 983 ret = clk_prepare_enable(i2c->clk); 984 if (ret) 985 goto err_pclk; 986 987 ret = exynos5_hsi2c_clock_setup(i2c); 988 if (ret) 989 goto err_clk; 990 991 exynos5_i2c_init(i2c); 992 clk_disable(i2c->clk); 993 clk_disable(i2c->pclk); 994 i2c_mark_adapter_resumed(&i2c->adap); 995 996 return 0; 997 998 err_clk: 999 clk_disable_unprepare(i2c->clk); 1000 err_pclk: 1001 clk_disable_unprepare(i2c->pclk); 1002 return ret; 1003 } 1004 1005 static const struct dev_pm_ops exynos5_i2c_dev_pm_ops = { 1006 NOIRQ_SYSTEM_SLEEP_PM_OPS(exynos5_i2c_suspend_noirq, 1007 exynos5_i2c_resume_noirq) 1008 }; 1009 1010 static struct platform_driver exynos5_i2c_driver = { 1011 .probe = exynos5_i2c_probe, 1012 .remove_new = exynos5_i2c_remove, 1013 .driver = { 1014 .name = "exynos5-hsi2c", 1015 .pm = pm_sleep_ptr(&exynos5_i2c_dev_pm_ops), 1016 .of_match_table = exynos5_i2c_match, 1017 }, 1018 }; 1019 1020 module_platform_driver(exynos5_i2c_driver); 1021 1022 MODULE_DESCRIPTION("Exynos5 HS-I2C Bus driver"); 1023 MODULE_AUTHOR("Naveen Krishna Chatradhi <ch.naveen@samsung.com>"); 1024 MODULE_AUTHOR("Taekgyun Ko <taeggyun.ko@samsung.com>"); 1025 MODULE_LICENSE("GPL v2"); 1026