1 /* 2 * Copyright 2006 Freescale Semiconductor, Inc. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * Version 2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 16 * MA 02111-1307 USA 17 */ 18 19 #include <common.h> 20 21 #ifdef CONFIG_FSL_I2C 22 #ifdef CONFIG_HARD_I2C 23 24 #include <command.h> 25 #include <i2c.h> /* Functional interface */ 26 27 #include <asm/io.h> 28 #include <asm/fsl_i2c.h> /* HW definitions */ 29 30 #define I2C_TIMEOUT (CFG_HZ / 4) 31 32 #define I2C_READ_BIT 1 33 #define I2C_WRITE_BIT 0 34 35 DECLARE_GLOBAL_DATA_PTR; 36 37 /* Initialize the bus pointer to whatever one the SPD EEPROM is on. 38 * Default is bus 0. This is necessary because the DDR initialization 39 * runs from ROM, and we can't switch buses because we can't modify 40 * the global variables. 41 */ 42 #ifdef CFG_SPD_BUS_NUM 43 static unsigned int i2c_bus_num __attribute__ ((section ("data"))) = CFG_SPD_BUS_NUM; 44 #else 45 static unsigned int i2c_bus_num __attribute__ ((section ("data"))) = 0; 46 #endif 47 48 static unsigned int i2c_bus_speed[2] = {CFG_I2C_SPEED, CFG_I2C_SPEED}; 49 50 static const struct fsl_i2c *i2c_dev[2] = { 51 (struct fsl_i2c *) (CFG_IMMR + CFG_I2C_OFFSET), 52 #ifdef CFG_I2C2_OFFSET 53 (struct fsl_i2c *) (CFG_IMMR + CFG_I2C2_OFFSET) 54 #endif 55 }; 56 57 /* I2C speed map for a DFSR value of 1 */ 58 59 /* 60 * Map I2C frequency dividers to FDR and DFSR values 61 * 62 * This structure is used to define the elements of a table that maps I2C 63 * frequency divider (I2C clock rate divided by I2C bus speed) to a value to be 64 * programmed into the Frequency Divider Ratio (FDR) and Digital Filter 65 * Sampling Rate (DFSR) registers. 66 * 67 * The actual table should be defined in the board file, and it must be called 68 * fsl_i2c_speed_map[]. 69 * 70 * The last entry of the table must have a value of {-1, X}, where X is same 71 * FDR/DFSR values as the second-to-last entry. This guarantees that any 72 * search through the array will always find a match. 73 * 74 * The values of the divider must be in increasing numerical order, i.e. 75 * fsl_i2c_speed_map[x+1].divider > fsl_i2c_speed_map[x].divider. 76 * 77 * For this table, the values are based on a value of 1 for the DFSR 78 * register. See the application note AN2919 "Determining the I2C Frequency 79 * Divider Ratio for SCL" 80 */ 81 static const struct { 82 unsigned short divider; 83 u8 dfsr; 84 u8 fdr; 85 } fsl_i2c_speed_map[] = { 86 {160, 1, 32}, {192, 1, 33}, {224, 1, 34}, {256, 1, 35}, 87 {288, 1, 0}, {320, 1, 1}, {352, 6, 1}, {384, 1, 2}, {416, 6, 2}, 88 {448, 1, 38}, {480, 1, 3}, {512, 1, 39}, {544, 11, 3}, {576, 1, 4}, 89 {608, 22, 3}, {640, 1, 5}, {672, 32, 3}, {704, 11, 5}, {736, 43, 3}, 90 {768, 1, 6}, {800, 54, 3}, {832, 11, 6}, {896, 1, 42}, {960, 1, 7}, 91 {1024, 1, 43}, {1088, 22, 7}, {1152, 1, 8}, {1216, 43, 7}, {1280, 1, 9}, 92 {1408, 22, 9}, {1536, 1, 10}, {1664, 22, 10}, {1792, 1, 46}, 93 {1920, 1, 11}, {2048, 1, 47}, {2176, 43, 11}, {2304, 1, 12}, 94 {2560, 1, 13}, {2816, 43, 13}, {3072, 1, 14}, {3328, 43, 14}, 95 {3584, 1, 50}, {3840, 1, 15}, {4096, 1, 51}, {4608, 1, 16}, 96 {5120, 1, 17}, {6144, 1, 18}, {7168, 1, 54}, {7680, 1, 19}, 97 {8192, 1, 55}, {9216, 1, 20}, {10240, 1, 21}, {12288, 1, 22}, 98 {14336, 1, 58}, {15360, 1, 23}, {16384, 1, 59}, {18432, 1, 24}, 99 {20480, 1, 25}, {24576, 1, 26}, {28672, 1, 62}, {30720, 1, 27}, 100 {32768, 1, 63}, {36864, 1, 28}, {40960, 1, 29}, {49152, 1, 30}, 101 {61440, 1, 31}, {-1, 1, 31} 102 }; 103 104 /** 105 * Set the I2C bus speed for a given I2C device 106 * 107 * @param dev: the I2C device 108 * @i2c_clk: I2C bus clock frequency 109 * @speed: the desired speed of the bus 110 * 111 * The I2C device must be stopped before calling this function. 112 * 113 * The return value is the actual bus speed that is set. 114 */ 115 static unsigned int set_i2c_bus_speed(const struct fsl_i2c *dev, 116 unsigned int i2c_clk, unsigned int speed) 117 { 118 unsigned short divider = min(i2c_clk / speed, (unsigned short) -1); 119 unsigned int i; 120 121 /* 122 * We want to choose an FDR/DFSR that generates an I2C bus speed that 123 * is equal to or lower than the requested speed. That means that we 124 * want the first divider that is equal to or greater than the 125 * calculated divider. 126 */ 127 128 for (i = 0; i < ARRAY_SIZE(fsl_i2c_speed_map); i++) 129 if (fsl_i2c_speed_map[i].divider >= divider) { 130 u8 fdr, dfsr; 131 dfsr = fsl_i2c_speed_map[i].dfsr; 132 fdr = fsl_i2c_speed_map[i].fdr; 133 speed = i2c_clk / fsl_i2c_speed_map[i].divider; 134 writeb(fdr, &dev->fdr); /* set bus speed */ 135 writeb(dfsr, &dev->dfsrr); /* set default filter */ 136 break; 137 } 138 139 return speed; 140 } 141 142 void 143 i2c_init(int speed, int slaveadd) 144 { 145 struct fsl_i2c *dev; 146 unsigned int temp; 147 148 dev = (struct fsl_i2c *) (CFG_IMMR + CFG_I2C_OFFSET); 149 150 writeb(0, &dev->cr); /* stop I2C controller */ 151 udelay(5); /* let it shutdown in peace */ 152 temp = set_i2c_bus_speed(dev, gd->i2c1_clk, speed); 153 if (gd->flags & GD_FLG_RELOC) 154 i2c_bus_speed[0] = temp; 155 writeb(slaveadd << 1, &dev->adr); /* write slave address */ 156 writeb(0x0, &dev->sr); /* clear status register */ 157 writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */ 158 159 #ifdef CFG_I2C2_OFFSET 160 dev = (struct fsl_i2c *) (CFG_IMMR + CFG_I2C2_OFFSET); 161 162 writeb(0, &dev->cr); /* stop I2C controller */ 163 udelay(5); /* let it shutdown in peace */ 164 temp = set_i2c_bus_speed(dev, gd->i2c2_clk, speed); 165 if (gd->flags & GD_FLG_RELOC) 166 i2c_bus_speed[1] = temp; 167 writeb(slaveadd << 1, &dev->adr); /* write slave address */ 168 writeb(0x0, &dev->sr); /* clear status register */ 169 writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */ 170 #endif 171 } 172 173 static __inline__ int 174 i2c_wait4bus(void) 175 { 176 ulong timeval = get_timer(0); 177 178 while (readb(&i2c_dev[i2c_bus_num]->sr) & I2C_SR_MBB) { 179 if (get_timer(timeval) > I2C_TIMEOUT) { 180 return -1; 181 } 182 } 183 184 return 0; 185 } 186 187 static __inline__ int 188 i2c_wait(int write) 189 { 190 u32 csr; 191 ulong timeval = get_timer(0); 192 193 do { 194 csr = readb(&i2c_dev[i2c_bus_num]->sr); 195 if (!(csr & I2C_SR_MIF)) 196 continue; 197 198 writeb(0x0, &i2c_dev[i2c_bus_num]->sr); 199 200 if (csr & I2C_SR_MAL) { 201 debug("i2c_wait: MAL\n"); 202 return -1; 203 } 204 205 if (!(csr & I2C_SR_MCF)) { 206 debug("i2c_wait: unfinished\n"); 207 return -1; 208 } 209 210 if (write == I2C_WRITE_BIT && (csr & I2C_SR_RXAK)) { 211 debug("i2c_wait: No RXACK\n"); 212 return -1; 213 } 214 215 return 0; 216 } while (get_timer (timeval) < I2C_TIMEOUT); 217 218 debug("i2c_wait: timed out\n"); 219 return -1; 220 } 221 222 static __inline__ int 223 i2c_write_addr (u8 dev, u8 dir, int rsta) 224 { 225 writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX 226 | (rsta ? I2C_CR_RSTA : 0), 227 &i2c_dev[i2c_bus_num]->cr); 228 229 writeb((dev << 1) | dir, &i2c_dev[i2c_bus_num]->dr); 230 231 if (i2c_wait(I2C_WRITE_BIT) < 0) 232 return 0; 233 234 return 1; 235 } 236 237 static __inline__ int 238 __i2c_write(u8 *data, int length) 239 { 240 int i; 241 242 writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX, 243 &i2c_dev[i2c_bus_num]->cr); 244 245 for (i = 0; i < length; i++) { 246 writeb(data[i], &i2c_dev[i2c_bus_num]->dr); 247 248 if (i2c_wait(I2C_WRITE_BIT) < 0) 249 break; 250 } 251 252 return i; 253 } 254 255 static __inline__ int 256 __i2c_read(u8 *data, int length) 257 { 258 int i; 259 260 writeb(I2C_CR_MEN | I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0), 261 &i2c_dev[i2c_bus_num]->cr); 262 263 /* dummy read */ 264 readb(&i2c_dev[i2c_bus_num]->dr); 265 266 for (i = 0; i < length; i++) { 267 if (i2c_wait(I2C_READ_BIT) < 0) 268 break; 269 270 /* Generate ack on last next to last byte */ 271 if (i == length - 2) 272 writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK, 273 &i2c_dev[i2c_bus_num]->cr); 274 275 /* Generate stop on last byte */ 276 if (i == length - 1) 277 writeb(I2C_CR_MEN | I2C_CR_TXAK, &i2c_dev[i2c_bus_num]->cr); 278 279 data[i] = readb(&i2c_dev[i2c_bus_num]->dr); 280 } 281 282 return i; 283 } 284 285 int 286 i2c_read(u8 dev, uint addr, int alen, u8 *data, int length) 287 { 288 int i = -1; /* signal error */ 289 u8 *a = (u8*)&addr; 290 291 if (i2c_wait4bus() >= 0 292 && i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0 293 && __i2c_write(&a[4 - alen], alen) == alen) 294 i = 0; /* No error so far */ 295 296 if (length 297 && i2c_write_addr(dev, I2C_READ_BIT, 1) != 0) 298 i = __i2c_read(data, length); 299 300 writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr); 301 302 if (i == length) 303 return 0; 304 305 return -1; 306 } 307 308 int 309 i2c_write(u8 dev, uint addr, int alen, u8 *data, int length) 310 { 311 int i = -1; /* signal error */ 312 u8 *a = (u8*)&addr; 313 314 if (i2c_wait4bus() >= 0 315 && i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0 316 && __i2c_write(&a[4 - alen], alen) == alen) { 317 i = __i2c_write(data, length); 318 } 319 320 writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr); 321 322 if (i == length) 323 return 0; 324 325 return -1; 326 } 327 328 int 329 i2c_probe(uchar chip) 330 { 331 /* For unknow reason the controller will ACK when 332 * probing for a slave with the same address, so skip 333 * it. 334 */ 335 if (chip == (readb(&i2c_dev[i2c_bus_num]->adr) >> 1)) 336 return -1; 337 338 return i2c_read(chip, 0, 0, NULL, 0); 339 } 340 341 uchar 342 i2c_reg_read(uchar i2c_addr, uchar reg) 343 { 344 uchar buf[1]; 345 346 i2c_read(i2c_addr, reg, 1, buf, 1); 347 348 return buf[0]; 349 } 350 351 void 352 i2c_reg_write(uchar i2c_addr, uchar reg, uchar val) 353 { 354 i2c_write(i2c_addr, reg, 1, &val, 1); 355 } 356 357 int i2c_set_bus_num(unsigned int bus) 358 { 359 #ifdef CFG_I2C2_OFFSET 360 if (bus > 1) { 361 #else 362 if (bus > 0) { 363 #endif 364 return -1; 365 } 366 367 i2c_bus_num = bus; 368 369 return 0; 370 } 371 372 int i2c_set_bus_speed(unsigned int speed) 373 { 374 unsigned int i2c_clk = (i2c_bus_num == 1) ? gd->i2c2_clk : gd->i2c1_clk; 375 376 writeb(0, &i2c_dev[i2c_bus_num]->cr); /* stop controller */ 377 i2c_bus_speed[i2c_bus_num] = 378 set_i2c_bus_speed(i2c_dev[i2c_bus_num], i2c_clk, speed); 379 writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr); /* start controller */ 380 381 return 0; 382 } 383 384 unsigned int i2c_get_bus_num(void) 385 { 386 return i2c_bus_num; 387 } 388 389 unsigned int i2c_get_bus_speed(void) 390 { 391 return i2c_bus_speed[i2c_bus_num]; 392 } 393 394 #endif /* CONFIG_HARD_I2C */ 395 #endif /* CONFIG_FSL_I2C */ 396