1 /* 2 * Copyright (C) 2008, Guennadi Liakhovetski <lg@denx.de> 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 as 6 * published by the Free Software Foundation; either version 2 of 7 * the License, or (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 17 * MA 02111-1307 USA 18 * 19 */ 20 21 #include <common.h> 22 #include <malloc.h> 23 #include <spi.h> 24 #include <asm/errno.h> 25 #include <asm/io.h> 26 #include <asm/gpio.h> 27 #include <asm/arch/imx-regs.h> 28 #include <asm/arch/clock.h> 29 30 #ifdef CONFIG_MX27 31 /* i.MX27 has a completely wrong register layout and register definitions in the 32 * datasheet, the correct one is in the Freescale's Linux driver */ 33 34 #error "i.MX27 CSPI not supported due to drastic differences in register definitions" \ 35 "See linux mxc_spi driver from Freescale for details." 36 #endif 37 38 static unsigned long spi_bases[] = { 39 MXC_SPI_BASE_ADDRESSES 40 }; 41 42 #define OUT MXC_GPIO_DIRECTION_OUT 43 44 #define reg_read readl 45 #define reg_write(a, v) writel(v, a) 46 47 struct mxc_spi_slave { 48 struct spi_slave slave; 49 unsigned long base; 50 u32 ctrl_reg; 51 #if defined(MXC_ECSPI) 52 u32 cfg_reg; 53 #endif 54 int gpio; 55 int ss_pol; 56 }; 57 58 static inline struct mxc_spi_slave *to_mxc_spi_slave(struct spi_slave *slave) 59 { 60 return container_of(slave, struct mxc_spi_slave, slave); 61 } 62 63 void spi_cs_activate(struct spi_slave *slave) 64 { 65 struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave); 66 if (mxcs->gpio > 0) 67 gpio_set_value(mxcs->gpio, mxcs->ss_pol); 68 } 69 70 void spi_cs_deactivate(struct spi_slave *slave) 71 { 72 struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave); 73 if (mxcs->gpio > 0) 74 gpio_set_value(mxcs->gpio, 75 !(mxcs->ss_pol)); 76 } 77 78 u32 get_cspi_div(u32 div) 79 { 80 int i; 81 82 for (i = 0; i < 8; i++) { 83 if (div <= (4 << i)) 84 return i; 85 } 86 return i; 87 } 88 89 #ifdef MXC_CSPI 90 static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs, 91 unsigned int max_hz, unsigned int mode) 92 { 93 unsigned int ctrl_reg; 94 u32 clk_src; 95 u32 div; 96 97 clk_src = mxc_get_clock(MXC_CSPI_CLK); 98 99 div = DIV_ROUND_UP(clk_src, max_hz); 100 div = get_cspi_div(div); 101 102 debug("clk %d Hz, div %d, real clk %d Hz\n", 103 max_hz, div, clk_src / (4 << div)); 104 105 ctrl_reg = MXC_CSPICTRL_CHIPSELECT(cs) | 106 MXC_CSPICTRL_BITCOUNT(MXC_CSPICTRL_MAXBITS) | 107 MXC_CSPICTRL_DATARATE(div) | 108 MXC_CSPICTRL_EN | 109 #ifdef CONFIG_MX35 110 MXC_CSPICTRL_SSCTL | 111 #endif 112 MXC_CSPICTRL_MODE; 113 114 if (mode & SPI_CPHA) 115 ctrl_reg |= MXC_CSPICTRL_PHA; 116 if (mode & SPI_CPOL) 117 ctrl_reg |= MXC_CSPICTRL_POL; 118 if (mode & SPI_CS_HIGH) 119 ctrl_reg |= MXC_CSPICTRL_SSPOL; 120 mxcs->ctrl_reg = ctrl_reg; 121 122 return 0; 123 } 124 #endif 125 126 #ifdef MXC_ECSPI 127 static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs, 128 unsigned int max_hz, unsigned int mode) 129 { 130 u32 clk_src = mxc_get_clock(MXC_CSPI_CLK); 131 s32 pre_div = 0, post_div = 0, i, reg_ctrl, reg_config; 132 u32 ss_pol = 0, sclkpol = 0, sclkpha = 0; 133 struct cspi_regs *regs = (struct cspi_regs *)mxcs->base; 134 135 if (max_hz == 0) { 136 printf("Error: desired clock is 0\n"); 137 return -1; 138 } 139 140 /* 141 * Reset SPI and set all CSs to master mode, if toggling 142 * between slave and master mode we might see a glitch 143 * on the clock line 144 */ 145 reg_ctrl = MXC_CSPICTRL_MODE_MASK; 146 reg_write(®s->ctrl, reg_ctrl); 147 reg_ctrl |= MXC_CSPICTRL_EN; 148 reg_write(®s->ctrl, reg_ctrl); 149 150 /* 151 * The following computation is taken directly from Freescale's code. 152 */ 153 if (clk_src > max_hz) { 154 pre_div = DIV_ROUND_UP(clk_src, max_hz); 155 if (pre_div > 16) { 156 post_div = pre_div / 16; 157 pre_div = 15; 158 } 159 if (post_div != 0) { 160 for (i = 0; i < 16; i++) { 161 if ((1 << i) >= post_div) 162 break; 163 } 164 if (i == 16) { 165 printf("Error: no divider for the freq: %d\n", 166 max_hz); 167 return -1; 168 } 169 post_div = i; 170 } 171 } 172 173 debug("pre_div = %d, post_div=%d\n", pre_div, post_div); 174 reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_SELCHAN(3)) | 175 MXC_CSPICTRL_SELCHAN(cs); 176 reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_PREDIV(0x0F)) | 177 MXC_CSPICTRL_PREDIV(pre_div); 178 reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_POSTDIV(0x0F)) | 179 MXC_CSPICTRL_POSTDIV(post_div); 180 181 /* We need to disable SPI before changing registers */ 182 reg_ctrl &= ~MXC_CSPICTRL_EN; 183 184 if (mode & SPI_CS_HIGH) 185 ss_pol = 1; 186 187 if (mode & SPI_CPOL) 188 sclkpol = 1; 189 190 if (mode & SPI_CPHA) 191 sclkpha = 1; 192 193 reg_config = reg_read(®s->cfg); 194 195 /* 196 * Configuration register setup 197 * The MX51 supports different setup for each SS 198 */ 199 reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_SSPOL))) | 200 (ss_pol << (cs + MXC_CSPICON_SSPOL)); 201 reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_POL))) | 202 (sclkpol << (cs + MXC_CSPICON_POL)); 203 reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_PHA))) | 204 (sclkpha << (cs + MXC_CSPICON_PHA)); 205 206 debug("reg_ctrl = 0x%x\n", reg_ctrl); 207 reg_write(®s->ctrl, reg_ctrl); 208 debug("reg_config = 0x%x\n", reg_config); 209 reg_write(®s->cfg, reg_config); 210 211 /* save config register and control register */ 212 mxcs->ctrl_reg = reg_ctrl; 213 mxcs->cfg_reg = reg_config; 214 215 /* clear interrupt reg */ 216 reg_write(®s->intr, 0); 217 reg_write(®s->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF); 218 219 return 0; 220 } 221 #endif 222 223 int spi_xchg_single(struct spi_slave *slave, unsigned int bitlen, 224 const u8 *dout, u8 *din, unsigned long flags) 225 { 226 struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave); 227 int nbytes = (bitlen + 7) / 8; 228 u32 data, cnt, i; 229 struct cspi_regs *regs = (struct cspi_regs *)mxcs->base; 230 231 debug("%s: bitlen %d dout 0x%x din 0x%x\n", 232 __func__, bitlen, (u32)dout, (u32)din); 233 234 mxcs->ctrl_reg = (mxcs->ctrl_reg & 235 ~MXC_CSPICTRL_BITCOUNT(MXC_CSPICTRL_MAXBITS)) | 236 MXC_CSPICTRL_BITCOUNT(bitlen - 1); 237 238 reg_write(®s->ctrl, mxcs->ctrl_reg | MXC_CSPICTRL_EN); 239 #ifdef MXC_ECSPI 240 reg_write(®s->cfg, mxcs->cfg_reg); 241 #endif 242 243 /* Clear interrupt register */ 244 reg_write(®s->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF); 245 246 /* 247 * The SPI controller works only with words, 248 * check if less than a word is sent. 249 * Access to the FIFO is only 32 bit 250 */ 251 if (bitlen % 32) { 252 data = 0; 253 cnt = (bitlen % 32) / 8; 254 if (dout) { 255 for (i = 0; i < cnt; i++) { 256 data = (data << 8) | (*dout++ & 0xFF); 257 } 258 } 259 debug("Sending SPI 0x%x\n", data); 260 261 reg_write(®s->txdata, data); 262 nbytes -= cnt; 263 } 264 265 data = 0; 266 267 while (nbytes > 0) { 268 data = 0; 269 if (dout) { 270 /* Buffer is not 32-bit aligned */ 271 if ((unsigned long)dout & 0x03) { 272 data = 0; 273 for (i = 0; i < 4; i++) 274 data = (data << 8) | (*dout++ & 0xFF); 275 } else { 276 data = *(u32 *)dout; 277 data = cpu_to_be32(data); 278 } 279 dout += 4; 280 } 281 debug("Sending SPI 0x%x\n", data); 282 reg_write(®s->txdata, data); 283 nbytes -= 4; 284 } 285 286 /* FIFO is written, now starts the transfer setting the XCH bit */ 287 reg_write(®s->ctrl, mxcs->ctrl_reg | 288 MXC_CSPICTRL_EN | MXC_CSPICTRL_XCH); 289 290 /* Wait until the TC (Transfer completed) bit is set */ 291 while ((reg_read(®s->stat) & MXC_CSPICTRL_TC) == 0) 292 ; 293 294 /* Transfer completed, clear any pending request */ 295 reg_write(®s->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF); 296 297 nbytes = (bitlen + 7) / 8; 298 299 cnt = nbytes % 32; 300 301 if (bitlen % 32) { 302 data = reg_read(®s->rxdata); 303 cnt = (bitlen % 32) / 8; 304 data = cpu_to_be32(data) >> ((sizeof(data) - cnt) * 8); 305 debug("SPI Rx unaligned: 0x%x\n", data); 306 if (din) { 307 memcpy(din, &data, cnt); 308 din += cnt; 309 } 310 nbytes -= cnt; 311 } 312 313 while (nbytes > 0) { 314 u32 tmp; 315 tmp = reg_read(®s->rxdata); 316 data = cpu_to_be32(tmp); 317 debug("SPI Rx: 0x%x 0x%x\n", tmp, data); 318 cnt = min(nbytes, sizeof(data)); 319 if (din) { 320 memcpy(din, &data, cnt); 321 din += cnt; 322 } 323 nbytes -= cnt; 324 } 325 326 return 0; 327 328 } 329 330 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, 331 void *din, unsigned long flags) 332 { 333 int n_bytes = (bitlen + 7) / 8; 334 int n_bits; 335 int ret; 336 u32 blk_size; 337 u8 *p_outbuf = (u8 *)dout; 338 u8 *p_inbuf = (u8 *)din; 339 340 if (!slave) 341 return -1; 342 343 if (flags & SPI_XFER_BEGIN) 344 spi_cs_activate(slave); 345 346 while (n_bytes > 0) { 347 if (n_bytes < MAX_SPI_BYTES) 348 blk_size = n_bytes; 349 else 350 blk_size = MAX_SPI_BYTES; 351 352 n_bits = blk_size * 8; 353 354 ret = spi_xchg_single(slave, n_bits, p_outbuf, p_inbuf, 0); 355 356 if (ret) 357 return ret; 358 if (dout) 359 p_outbuf += blk_size; 360 if (din) 361 p_inbuf += blk_size; 362 n_bytes -= blk_size; 363 } 364 365 if (flags & SPI_XFER_END) { 366 spi_cs_deactivate(slave); 367 } 368 369 return 0; 370 } 371 372 void spi_init(void) 373 { 374 } 375 376 static int decode_cs(struct mxc_spi_slave *mxcs, unsigned int cs) 377 { 378 int ret; 379 380 /* 381 * Some SPI devices require active chip-select over multiple 382 * transactions, we achieve this using a GPIO. Still, the SPI 383 * controller has to be configured to use one of its own chipselects. 384 * To use this feature you have to call spi_setup_slave() with 385 * cs = internal_cs | (gpio << 8), and you have to use some unused 386 * on this SPI controller cs between 0 and 3. 387 */ 388 if (cs > 3) { 389 mxcs->gpio = cs >> 8; 390 cs &= 3; 391 ret = gpio_direction_output(mxcs->gpio, !(mxcs->ss_pol)); 392 if (ret) { 393 printf("mxc_spi: cannot setup gpio %d\n", mxcs->gpio); 394 return -EINVAL; 395 } 396 } else { 397 mxcs->gpio = -1; 398 } 399 400 return cs; 401 } 402 403 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, 404 unsigned int max_hz, unsigned int mode) 405 { 406 struct mxc_spi_slave *mxcs; 407 int ret; 408 409 if (bus >= ARRAY_SIZE(spi_bases)) 410 return NULL; 411 412 mxcs = spi_alloc_slave(struct mxc_spi_slave, bus, cs); 413 if (!mxcs) { 414 puts("mxc_spi: SPI Slave not allocated !\n"); 415 return NULL; 416 } 417 418 mxcs->ss_pol = (mode & SPI_CS_HIGH) ? 1 : 0; 419 420 ret = decode_cs(mxcs, cs); 421 if (ret < 0) { 422 free(mxcs); 423 return NULL; 424 } 425 426 cs = ret; 427 428 mxcs->base = spi_bases[bus]; 429 430 ret = spi_cfg_mxc(mxcs, cs, max_hz, mode); 431 if (ret) { 432 printf("mxc_spi: cannot setup SPI controller\n"); 433 free(mxcs); 434 return NULL; 435 } 436 return &mxcs->slave; 437 } 438 439 void spi_free_slave(struct spi_slave *slave) 440 { 441 struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave); 442 443 free(mxcs); 444 } 445 446 int spi_claim_bus(struct spi_slave *slave) 447 { 448 struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave); 449 struct cspi_regs *regs = (struct cspi_regs *)mxcs->base; 450 451 reg_write(®s->rxdata, 1); 452 udelay(1); 453 reg_write(®s->ctrl, mxcs->ctrl_reg); 454 reg_write(®s->period, MXC_CSPIPERIOD_32KHZ); 455 reg_write(®s->intr, 0); 456 457 return 0; 458 } 459 460 void spi_release_bus(struct spi_slave *slave) 461 { 462 /* TODO: Shut the controller down */ 463 } 464