1 /* 2 * i2c driver for Freescale i.MX series 3 * 4 * (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de> 5 * (c) 2011 Marek Vasut <marek.vasut@gmail.com> 6 * 7 * Based on i2c-imx.c from linux kernel: 8 * Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de> 9 * Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de> 10 * Copyright (C) 2007 RightHand Technologies, Inc. 11 * Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt> 12 * 13 * 14 * See file CREDITS for list of people who contributed to this 15 * project. 16 * 17 * This program is free software; you can redistribute it and/or 18 * modify it under the terms of the GNU General Public License as 19 * published by the Free Software Foundation; either version 2 of 20 * the License, or (at your option) any later version. 21 * 22 * This program is distributed in the hope that it will be useful, 23 * but WITHOUT ANY WARRANTY; without even the implied warranty of 24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 25 * GNU General Public License for more details. 26 * 27 * You should have received a copy of the GNU General Public License 28 * along with this program; if not, write to the Free Software 29 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 30 * MA 02111-1307 USA 31 */ 32 33 #include <common.h> 34 #include <asm/arch/clock.h> 35 #include <asm/arch/imx-regs.h> 36 #include <asm/errno.h> 37 #include <asm/io.h> 38 #include <i2c.h> 39 #include <watchdog.h> 40 41 struct mxc_i2c_regs { 42 uint32_t iadr; 43 uint32_t ifdr; 44 uint32_t i2cr; 45 uint32_t i2sr; 46 uint32_t i2dr; 47 }; 48 49 #define I2CR_IEN (1 << 7) 50 #define I2CR_IIEN (1 << 6) 51 #define I2CR_MSTA (1 << 5) 52 #define I2CR_MTX (1 << 4) 53 #define I2CR_TX_NO_AK (1 << 3) 54 #define I2CR_RSTA (1 << 2) 55 56 #define I2SR_ICF (1 << 7) 57 #define I2SR_IBB (1 << 5) 58 #define I2SR_IAL (1 << 4) 59 #define I2SR_IIF (1 << 1) 60 #define I2SR_RX_NO_AK (1 << 0) 61 62 #if defined(CONFIG_HARD_I2C) && !defined(CONFIG_SYS_I2C_BASE) 63 #error "define CONFIG_SYS_I2C_BASE to use the mxc_i2c driver" 64 #endif 65 66 static u16 i2c_clk_div[50][2] = { 67 { 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 }, 68 { 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 }, 69 { 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 }, 70 { 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B }, 71 { 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A }, 72 { 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 }, 73 { 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 }, 74 { 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 }, 75 { 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 }, 76 { 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B }, 77 { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E }, 78 { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D }, 79 { 3072, 0x1E }, { 3840, 0x1F } 80 }; 81 82 /* 83 * Calculate and set proper clock divider 84 */ 85 static uint8_t i2c_imx_get_clk(unsigned int rate) 86 { 87 unsigned int i2c_clk_rate; 88 unsigned int div; 89 u8 clk_div; 90 91 #if defined(CONFIG_MX31) 92 struct clock_control_regs *sc_regs = 93 (struct clock_control_regs *)CCM_BASE; 94 95 /* start the required I2C clock */ 96 writel(readl(&sc_regs->cgr0) | (3 << CONFIG_SYS_I2C_CLK_OFFSET), 97 &sc_regs->cgr0); 98 #endif 99 100 /* Divider value calculation */ 101 i2c_clk_rate = mxc_get_clock(MXC_I2C_CLK); 102 div = (i2c_clk_rate + rate - 1) / rate; 103 if (div < i2c_clk_div[0][0]) 104 clk_div = 0; 105 else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0]) 106 clk_div = ARRAY_SIZE(i2c_clk_div) - 1; 107 else 108 for (clk_div = 0; i2c_clk_div[clk_div][0] < div; clk_div++) 109 ; 110 111 /* Store divider value */ 112 return clk_div; 113 } 114 115 /* 116 * Set I2C Bus speed 117 */ 118 static int bus_i2c_set_bus_speed(void *base, int speed) 119 { 120 struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)base; 121 u8 clk_idx = i2c_imx_get_clk(speed); 122 u8 idx = i2c_clk_div[clk_idx][1]; 123 124 /* Store divider value */ 125 writeb(idx, &i2c_regs->ifdr); 126 127 /* Reset module */ 128 writeb(0, &i2c_regs->i2cr); 129 writeb(0, &i2c_regs->i2sr); 130 return 0; 131 } 132 133 /* 134 * Get I2C Speed 135 */ 136 static unsigned int bus_i2c_get_bus_speed(void *base) 137 { 138 struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)base; 139 u8 clk_idx = readb(&i2c_regs->ifdr); 140 u8 clk_div; 141 142 for (clk_div = 0; i2c_clk_div[clk_div][1] != clk_idx; clk_div++) 143 ; 144 145 return mxc_get_clock(MXC_I2C_CLK) / i2c_clk_div[clk_div][0]; 146 } 147 148 #define ST_BUS_IDLE (0 | (I2SR_IBB << 8)) 149 #define ST_BUS_BUSY (I2SR_IBB | (I2SR_IBB << 8)) 150 #define ST_IIF (I2SR_IIF | (I2SR_IIF << 8)) 151 152 static int wait_for_sr_state(struct mxc_i2c_regs *i2c_regs, unsigned state) 153 { 154 unsigned sr; 155 ulong elapsed; 156 ulong start_time = get_timer(0); 157 for (;;) { 158 sr = readb(&i2c_regs->i2sr); 159 if (sr & I2SR_IAL) { 160 writeb(sr & ~I2SR_IAL, &i2c_regs->i2sr); 161 printf("%s: Arbitration lost sr=%x cr=%x state=%x\n", 162 __func__, sr, readb(&i2c_regs->i2cr), state); 163 return -ERESTART; 164 } 165 if ((sr & (state >> 8)) == (unsigned char)state) 166 return sr; 167 WATCHDOG_RESET(); 168 elapsed = get_timer(start_time); 169 if (elapsed > (CONFIG_SYS_HZ / 10)) /* .1 seconds */ 170 break; 171 } 172 printf("%s: failed sr=%x cr=%x state=%x\n", __func__, 173 sr, readb(&i2c_regs->i2cr), state); 174 return -ETIMEDOUT; 175 } 176 177 static int tx_byte(struct mxc_i2c_regs *i2c_regs, u8 byte) 178 { 179 int ret; 180 181 writeb(0, &i2c_regs->i2sr); 182 writeb(byte, &i2c_regs->i2dr); 183 ret = wait_for_sr_state(i2c_regs, ST_IIF); 184 if (ret < 0) 185 return ret; 186 if (ret & I2SR_RX_NO_AK) 187 return -ENODEV; 188 return 0; 189 } 190 191 /* 192 * Stop I2C transaction 193 */ 194 static void i2c_imx_stop(struct mxc_i2c_regs *i2c_regs) 195 { 196 int ret; 197 unsigned int temp = readb(&i2c_regs->i2cr); 198 199 temp &= ~(I2CR_MSTA | I2CR_MTX); 200 writeb(temp, &i2c_regs->i2cr); 201 ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE); 202 if (ret < 0) 203 printf("%s:trigger stop failed\n", __func__); 204 } 205 206 /* 207 * Send start signal, chip address and 208 * write register address 209 */ 210 static int i2c_init_transfer_(struct mxc_i2c_regs *i2c_regs, 211 uchar chip, uint addr, int alen) 212 { 213 unsigned int temp; 214 int ret; 215 216 /* Enable I2C controller */ 217 if (!(readb(&i2c_regs->i2cr) & I2CR_IEN)) { 218 writeb(I2CR_IEN, &i2c_regs->i2cr); 219 /* Wait for controller to be stable */ 220 udelay(50); 221 } 222 if (readb(&i2c_regs->iadr) == (chip << 1)) 223 writeb((chip << 1) ^ 2, &i2c_regs->iadr); 224 writeb(0, &i2c_regs->i2sr); 225 ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE); 226 if (ret < 0) 227 return ret; 228 229 /* Start I2C transaction */ 230 temp = readb(&i2c_regs->i2cr); 231 temp |= I2CR_MSTA; 232 writeb(temp, &i2c_regs->i2cr); 233 234 ret = wait_for_sr_state(i2c_regs, ST_BUS_BUSY); 235 if (ret < 0) 236 return ret; 237 238 temp |= I2CR_MTX | I2CR_TX_NO_AK; 239 writeb(temp, &i2c_regs->i2cr); 240 241 /* write slave address */ 242 ret = tx_byte(i2c_regs, chip << 1); 243 if (ret < 0) 244 return ret; 245 246 while (alen--) { 247 ret = tx_byte(i2c_regs, (addr >> (alen * 8)) & 0xff); 248 if (ret < 0) 249 return ret; 250 } 251 return 0; 252 } 253 254 static int i2c_idle_bus(void *base); 255 256 static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, 257 uchar chip, uint addr, int alen) 258 { 259 int retry; 260 int ret; 261 for (retry = 0; retry < 3; retry++) { 262 ret = i2c_init_transfer_(i2c_regs, chip, addr, alen); 263 if (ret >= 0) 264 return 0; 265 i2c_imx_stop(i2c_regs); 266 if (ret == -ENODEV) 267 return ret; 268 269 printf("%s: failed for chip 0x%x retry=%d\n", __func__, chip, 270 retry); 271 if (ret != -ERESTART) 272 writeb(0, &i2c_regs->i2cr); /* Disable controller */ 273 udelay(100); 274 if (i2c_idle_bus(i2c_regs) < 0) 275 break; 276 } 277 printf("%s: give up i2c_regs=%p\n", __func__, i2c_regs); 278 return ret; 279 } 280 281 /* 282 * Read data from I2C device 283 */ 284 int bus_i2c_read(void *base, uchar chip, uint addr, int alen, uchar *buf, 285 int len) 286 { 287 int ret; 288 unsigned int temp; 289 int i; 290 struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)base; 291 292 ret = i2c_init_transfer(i2c_regs, chip, addr, alen); 293 if (ret < 0) 294 return ret; 295 296 temp = readb(&i2c_regs->i2cr); 297 temp |= I2CR_RSTA; 298 writeb(temp, &i2c_regs->i2cr); 299 300 ret = tx_byte(i2c_regs, (chip << 1) | 1); 301 if (ret < 0) { 302 i2c_imx_stop(i2c_regs); 303 return ret; 304 } 305 306 /* setup bus to read data */ 307 temp = readb(&i2c_regs->i2cr); 308 temp &= ~(I2CR_MTX | I2CR_TX_NO_AK); 309 if (len == 1) 310 temp |= I2CR_TX_NO_AK; 311 writeb(temp, &i2c_regs->i2cr); 312 writeb(0, &i2c_regs->i2sr); 313 readb(&i2c_regs->i2dr); /* dummy read to clear ICF */ 314 315 /* read data */ 316 for (i = 0; i < len; i++) { 317 ret = wait_for_sr_state(i2c_regs, ST_IIF); 318 if (ret < 0) { 319 i2c_imx_stop(i2c_regs); 320 return ret; 321 } 322 323 /* 324 * It must generate STOP before read I2DR to prevent 325 * controller from generating another clock cycle 326 */ 327 if (i == (len - 1)) { 328 i2c_imx_stop(i2c_regs); 329 } else if (i == (len - 2)) { 330 temp = readb(&i2c_regs->i2cr); 331 temp |= I2CR_TX_NO_AK; 332 writeb(temp, &i2c_regs->i2cr); 333 } 334 writeb(0, &i2c_regs->i2sr); 335 buf[i] = readb(&i2c_regs->i2dr); 336 } 337 i2c_imx_stop(i2c_regs); 338 return 0; 339 } 340 341 /* 342 * Write data to I2C device 343 */ 344 int bus_i2c_write(void *base, uchar chip, uint addr, int alen, 345 const uchar *buf, int len) 346 { 347 int ret; 348 int i; 349 struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)base; 350 351 ret = i2c_init_transfer(i2c_regs, chip, addr, alen); 352 if (ret < 0) 353 return ret; 354 355 for (i = 0; i < len; i++) { 356 ret = tx_byte(i2c_regs, buf[i]); 357 if (ret < 0) 358 break; 359 } 360 i2c_imx_stop(i2c_regs); 361 return ret; 362 } 363 364 struct i2c_parms { 365 void *base; 366 void *idle_bus_data; 367 int (*idle_bus_fn)(void *p); 368 }; 369 370 struct sram_data { 371 unsigned curr_i2c_bus; 372 struct i2c_parms i2c_data[3]; 373 }; 374 375 /* 376 * For SPL boot some boards need i2c before SDRAM is initialized so force 377 * variables to live in SRAM 378 */ 379 static struct sram_data __attribute__((section(".data"))) srdata; 380 381 void *get_base(void) 382 { 383 #ifdef CONFIG_SYS_I2C_BASE 384 #ifdef CONFIG_I2C_MULTI_BUS 385 void *ret = srdata.i2c_data[srdata.curr_i2c_bus].base; 386 if (ret) 387 return ret; 388 #endif 389 return (void *)CONFIG_SYS_I2C_BASE; 390 #elif defined(CONFIG_I2C_MULTI_BUS) 391 return srdata.i2c_data[srdata.curr_i2c_bus].base; 392 #else 393 return srdata.i2c_data[0].base; 394 #endif 395 } 396 397 static struct i2c_parms *i2c_get_parms(void *base) 398 { 399 int i = 0; 400 struct i2c_parms *p = srdata.i2c_data; 401 while (i < ARRAY_SIZE(srdata.i2c_data)) { 402 if (p->base == base) 403 return p; 404 p++; 405 i++; 406 } 407 printf("Invalid I2C base: %p\n", base); 408 return NULL; 409 } 410 411 static int i2c_idle_bus(void *base) 412 { 413 struct i2c_parms *p = i2c_get_parms(base); 414 if (p && p->idle_bus_fn) 415 return p->idle_bus_fn(p->idle_bus_data); 416 return 0; 417 } 418 419 #ifdef CONFIG_I2C_MULTI_BUS 420 unsigned int i2c_get_bus_num(void) 421 { 422 return srdata.curr_i2c_bus; 423 } 424 425 int i2c_set_bus_num(unsigned bus_idx) 426 { 427 if (bus_idx >= ARRAY_SIZE(srdata.i2c_data)) 428 return -1; 429 if (!srdata.i2c_data[bus_idx].base) 430 return -1; 431 srdata.curr_i2c_bus = bus_idx; 432 return 0; 433 } 434 #endif 435 436 int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len) 437 { 438 return bus_i2c_read(get_base(), chip, addr, alen, buf, len); 439 } 440 441 int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len) 442 { 443 return bus_i2c_write(get_base(), chip, addr, alen, buf, len); 444 } 445 446 /* 447 * Test if a chip at a given address responds (probe the chip) 448 */ 449 int i2c_probe(uchar chip) 450 { 451 return bus_i2c_write(get_base(), chip, 0, 0, NULL, 0); 452 } 453 454 void bus_i2c_init(void *base, int speed, int unused, 455 int (*idle_bus_fn)(void *p), void *idle_bus_data) 456 { 457 int i = 0; 458 struct i2c_parms *p = srdata.i2c_data; 459 if (!base) 460 return; 461 for (;;) { 462 if (!p->base || (p->base == base)) { 463 p->base = base; 464 if (idle_bus_fn) { 465 p->idle_bus_fn = idle_bus_fn; 466 p->idle_bus_data = idle_bus_data; 467 } 468 break; 469 } 470 p++; 471 i++; 472 if (i >= ARRAY_SIZE(srdata.i2c_data)) 473 return; 474 } 475 bus_i2c_set_bus_speed(base, speed); 476 } 477 478 /* 479 * Init I2C Bus 480 */ 481 void i2c_init(int speed, int unused) 482 { 483 bus_i2c_init(get_base(), speed, unused, NULL, NULL); 484 } 485 486 /* 487 * Set I2C Speed 488 */ 489 int i2c_set_bus_speed(unsigned int speed) 490 { 491 return bus_i2c_set_bus_speed(get_base(), speed); 492 } 493 494 /* 495 * Get I2C Speed 496 */ 497 unsigned int i2c_get_bus_speed(void) 498 { 499 return bus_i2c_get_bus_speed(get_base()); 500 } 501