1 /* 2 * MicroWire interface driver for OMAP 3 * 4 * Copyright 2003 MontaVista Software Inc. <source@mvista.com> 5 * 6 * Ported to 2.6 OMAP uwire interface. 7 * Copyright (C) 2004 Texas Instruments. 8 * 9 * Generalization patches by Juha Yrjola <juha.yrjola@nokia.com> 10 * 11 * Copyright (C) 2005 David Brownell (ported to 2.6 SPI interface) 12 * Copyright (C) 2006 Nokia 13 * 14 * Many updates by Imre Deak <imre.deak@nokia.com> 15 * 16 * This program is free software; you can redistribute it and/or modify it 17 * under the terms of the GNU General Public License as published by the 18 * Free Software Foundation; either version 2 of the License, or (at your 19 * option) any later version. 20 * 21 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED 22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 27 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 28 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 * 32 * You should have received a copy of the GNU General Public License along 33 * with this program; if not, write to the Free Software Foundation, Inc., 34 * 675 Mass Ave, Cambridge, MA 02139, USA. 35 */ 36 #include <linux/kernel.h> 37 #include <linux/init.h> 38 #include <linux/delay.h> 39 #include <linux/platform_device.h> 40 #include <linux/interrupt.h> 41 #include <linux/err.h> 42 #include <linux/clk.h> 43 #include <linux/slab.h> 44 #include <linux/device.h> 45 46 #include <linux/spi/spi.h> 47 #include <linux/spi/spi_bitbang.h> 48 #include <linux/module.h> 49 #include <linux/io.h> 50 51 #include <asm/irq.h> 52 #include <mach/hardware.h> 53 #include <asm/mach-types.h> 54 55 #include <mach/mux.h> 56 57 #include <mach/omap7xx.h> /* OMAP7XX_IO_CONF registers */ 58 59 60 /* FIXME address is now a platform device resource, 61 * and irqs should show there too... 62 */ 63 #define UWIRE_BASE_PHYS 0xFFFB3000 64 65 /* uWire Registers: */ 66 #define UWIRE_IO_SIZE 0x20 67 #define UWIRE_TDR 0x00 68 #define UWIRE_RDR 0x00 69 #define UWIRE_CSR 0x01 70 #define UWIRE_SR1 0x02 71 #define UWIRE_SR2 0x03 72 #define UWIRE_SR3 0x04 73 #define UWIRE_SR4 0x05 74 #define UWIRE_SR5 0x06 75 76 /* CSR bits */ 77 #define RDRB (1 << 15) 78 #define CSRB (1 << 14) 79 #define START (1 << 13) 80 #define CS_CMD (1 << 12) 81 82 /* SR1 or SR2 bits */ 83 #define UWIRE_READ_FALLING_EDGE 0x0001 84 #define UWIRE_READ_RISING_EDGE 0x0000 85 #define UWIRE_WRITE_FALLING_EDGE 0x0000 86 #define UWIRE_WRITE_RISING_EDGE 0x0002 87 #define UWIRE_CS_ACTIVE_LOW 0x0000 88 #define UWIRE_CS_ACTIVE_HIGH 0x0004 89 #define UWIRE_FREQ_DIV_2 0x0000 90 #define UWIRE_FREQ_DIV_4 0x0008 91 #define UWIRE_FREQ_DIV_8 0x0010 92 #define UWIRE_CHK_READY 0x0020 93 #define UWIRE_CLK_INVERTED 0x0040 94 95 96 struct uwire_spi { 97 struct spi_bitbang bitbang; 98 struct clk *ck; 99 }; 100 101 struct uwire_state { 102 unsigned div1_idx; 103 }; 104 105 /* REVISIT compile time constant for idx_shift? */ 106 /* 107 * Or, put it in a structure which is used throughout the driver; 108 * that avoids having to issue two loads for each bit of static data. 109 */ 110 static unsigned int uwire_idx_shift; 111 static void __iomem *uwire_base; 112 113 static inline void uwire_write_reg(int idx, u16 val) 114 { 115 __raw_writew(val, uwire_base + (idx << uwire_idx_shift)); 116 } 117 118 static inline u16 uwire_read_reg(int idx) 119 { 120 return __raw_readw(uwire_base + (idx << uwire_idx_shift)); 121 } 122 123 static inline void omap_uwire_configure_mode(u8 cs, unsigned long flags) 124 { 125 u16 w, val = 0; 126 int shift, reg; 127 128 if (flags & UWIRE_CLK_INVERTED) 129 val ^= 0x03; 130 val = flags & 0x3f; 131 if (cs & 1) 132 shift = 6; 133 else 134 shift = 0; 135 if (cs <= 1) 136 reg = UWIRE_SR1; 137 else 138 reg = UWIRE_SR2; 139 140 w = uwire_read_reg(reg); 141 w &= ~(0x3f << shift); 142 w |= val << shift; 143 uwire_write_reg(reg, w); 144 } 145 146 static int wait_uwire_csr_flag(u16 mask, u16 val, int might_not_catch) 147 { 148 u16 w; 149 int c = 0; 150 unsigned long max_jiffies = jiffies + HZ; 151 152 for (;;) { 153 w = uwire_read_reg(UWIRE_CSR); 154 if ((w & mask) == val) 155 break; 156 if (time_after(jiffies, max_jiffies)) { 157 printk(KERN_ERR "%s: timeout. reg=%#06x " 158 "mask=%#06x val=%#06x\n", 159 __func__, w, mask, val); 160 return -1; 161 } 162 c++; 163 if (might_not_catch && c > 64) 164 break; 165 } 166 return 0; 167 } 168 169 static void uwire_set_clk1_div(int div1_idx) 170 { 171 u16 w; 172 173 w = uwire_read_reg(UWIRE_SR3); 174 w &= ~(0x03 << 1); 175 w |= div1_idx << 1; 176 uwire_write_reg(UWIRE_SR3, w); 177 } 178 179 static void uwire_chipselect(struct spi_device *spi, int value) 180 { 181 struct uwire_state *ust = spi->controller_state; 182 u16 w; 183 int old_cs; 184 185 186 BUG_ON(wait_uwire_csr_flag(CSRB, 0, 0)); 187 188 w = uwire_read_reg(UWIRE_CSR); 189 old_cs = (w >> 10) & 0x03; 190 if (value == BITBANG_CS_INACTIVE || old_cs != spi->chip_select) { 191 /* Deselect this CS, or the previous CS */ 192 w &= ~CS_CMD; 193 uwire_write_reg(UWIRE_CSR, w); 194 } 195 /* activate specfied chipselect */ 196 if (value == BITBANG_CS_ACTIVE) { 197 uwire_set_clk1_div(ust->div1_idx); 198 /* invert clock? */ 199 if (spi->mode & SPI_CPOL) 200 uwire_write_reg(UWIRE_SR4, 1); 201 else 202 uwire_write_reg(UWIRE_SR4, 0); 203 204 w = spi->chip_select << 10; 205 w |= CS_CMD; 206 uwire_write_reg(UWIRE_CSR, w); 207 } 208 } 209 210 static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t) 211 { 212 unsigned len = t->len; 213 unsigned bits = t->bits_per_word ? : spi->bits_per_word; 214 unsigned bytes; 215 u16 val, w; 216 int status = 0; 217 218 if (!t->tx_buf && !t->rx_buf) 219 return 0; 220 221 w = spi->chip_select << 10; 222 w |= CS_CMD; 223 224 if (t->tx_buf) { 225 const u8 *buf = t->tx_buf; 226 227 /* NOTE: DMA could be used for TX transfers */ 228 229 /* write one or two bytes at a time */ 230 while (len >= 1) { 231 /* tx bit 15 is first sent; we byteswap multibyte words 232 * (msb-first) on the way out from memory. 233 */ 234 val = *buf++; 235 if (bits > 8) { 236 bytes = 2; 237 val |= *buf++ << 8; 238 } else 239 bytes = 1; 240 val <<= 16 - bits; 241 242 #ifdef VERBOSE 243 pr_debug("%s: write-%d =%04x\n", 244 dev_name(&spi->dev), bits, val); 245 #endif 246 if (wait_uwire_csr_flag(CSRB, 0, 0)) 247 goto eio; 248 249 uwire_write_reg(UWIRE_TDR, val); 250 251 /* start write */ 252 val = START | w | (bits << 5); 253 254 uwire_write_reg(UWIRE_CSR, val); 255 len -= bytes; 256 257 /* Wait till write actually starts. 258 * This is needed with MPU clock 60+ MHz. 259 * REVISIT: we may not have time to catch it... 260 */ 261 if (wait_uwire_csr_flag(CSRB, CSRB, 1)) 262 goto eio; 263 264 status += bytes; 265 } 266 267 /* REVISIT: save this for later to get more i/o overlap */ 268 if (wait_uwire_csr_flag(CSRB, 0, 0)) 269 goto eio; 270 271 } else if (t->rx_buf) { 272 u8 *buf = t->rx_buf; 273 274 /* read one or two bytes at a time */ 275 while (len) { 276 if (bits > 8) { 277 bytes = 2; 278 } else 279 bytes = 1; 280 281 /* start read */ 282 val = START | w | (bits << 0); 283 uwire_write_reg(UWIRE_CSR, val); 284 len -= bytes; 285 286 /* Wait till read actually starts */ 287 (void) wait_uwire_csr_flag(CSRB, CSRB, 1); 288 289 if (wait_uwire_csr_flag(RDRB | CSRB, 290 RDRB, 0)) 291 goto eio; 292 293 /* rx bit 0 is last received; multibyte words will 294 * be properly byteswapped on the way to memory. 295 */ 296 val = uwire_read_reg(UWIRE_RDR); 297 val &= (1 << bits) - 1; 298 *buf++ = (u8) val; 299 if (bytes == 2) 300 *buf++ = val >> 8; 301 status += bytes; 302 #ifdef VERBOSE 303 pr_debug("%s: read-%d =%04x\n", 304 dev_name(&spi->dev), bits, val); 305 #endif 306 307 } 308 } 309 return status; 310 eio: 311 return -EIO; 312 } 313 314 static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t) 315 { 316 struct uwire_state *ust = spi->controller_state; 317 struct uwire_spi *uwire; 318 unsigned flags = 0; 319 unsigned hz; 320 unsigned long rate; 321 int div1_idx; 322 int div1; 323 int div2; 324 int status; 325 326 uwire = spi_master_get_devdata(spi->master); 327 328 /* mode 0..3, clock inverted separately; 329 * standard nCS signaling; 330 * don't treat DI=high as "not ready" 331 */ 332 if (spi->mode & SPI_CS_HIGH) 333 flags |= UWIRE_CS_ACTIVE_HIGH; 334 335 if (spi->mode & SPI_CPOL) 336 flags |= UWIRE_CLK_INVERTED; 337 338 switch (spi->mode & (SPI_CPOL | SPI_CPHA)) { 339 case SPI_MODE_0: 340 case SPI_MODE_3: 341 flags |= UWIRE_WRITE_FALLING_EDGE | UWIRE_READ_RISING_EDGE; 342 break; 343 case SPI_MODE_1: 344 case SPI_MODE_2: 345 flags |= UWIRE_WRITE_RISING_EDGE | UWIRE_READ_FALLING_EDGE; 346 break; 347 } 348 349 /* assume it's already enabled */ 350 rate = clk_get_rate(uwire->ck); 351 352 hz = spi->max_speed_hz; 353 if (t != NULL && t->speed_hz) 354 hz = t->speed_hz; 355 356 if (!hz) { 357 pr_debug("%s: zero speed?\n", dev_name(&spi->dev)); 358 status = -EINVAL; 359 goto done; 360 } 361 362 /* F_INT = mpu_xor_clk / DIV1 */ 363 for (div1_idx = 0; div1_idx < 4; div1_idx++) { 364 switch (div1_idx) { 365 case 0: 366 div1 = 2; 367 break; 368 case 1: 369 div1 = 4; 370 break; 371 case 2: 372 div1 = 7; 373 break; 374 default: 375 case 3: 376 div1 = 10; 377 break; 378 } 379 div2 = (rate / div1 + hz - 1) / hz; 380 if (div2 <= 8) 381 break; 382 } 383 if (div1_idx == 4) { 384 pr_debug("%s: lowest clock %ld, need %d\n", 385 dev_name(&spi->dev), rate / 10 / 8, hz); 386 status = -EDOM; 387 goto done; 388 } 389 390 /* we have to cache this and reset in uwire_chipselect as this is a 391 * global parameter and another uwire device can change it under 392 * us */ 393 ust->div1_idx = div1_idx; 394 uwire_set_clk1_div(div1_idx); 395 396 rate /= div1; 397 398 switch (div2) { 399 case 0: 400 case 1: 401 case 2: 402 flags |= UWIRE_FREQ_DIV_2; 403 rate /= 2; 404 break; 405 case 3: 406 case 4: 407 flags |= UWIRE_FREQ_DIV_4; 408 rate /= 4; 409 break; 410 case 5: 411 case 6: 412 case 7: 413 case 8: 414 flags |= UWIRE_FREQ_DIV_8; 415 rate /= 8; 416 break; 417 } 418 omap_uwire_configure_mode(spi->chip_select, flags); 419 pr_debug("%s: uwire flags %02x, armxor %lu KHz, SCK %lu KHz\n", 420 __func__, flags, 421 clk_get_rate(uwire->ck) / 1000, 422 rate / 1000); 423 status = 0; 424 done: 425 return status; 426 } 427 428 static int uwire_setup(struct spi_device *spi) 429 { 430 struct uwire_state *ust = spi->controller_state; 431 432 if (ust == NULL) { 433 ust = kzalloc(sizeof(*ust), GFP_KERNEL); 434 if (ust == NULL) 435 return -ENOMEM; 436 spi->controller_state = ust; 437 } 438 439 return uwire_setup_transfer(spi, NULL); 440 } 441 442 static void uwire_cleanup(struct spi_device *spi) 443 { 444 kfree(spi->controller_state); 445 } 446 447 static void uwire_off(struct uwire_spi *uwire) 448 { 449 uwire_write_reg(UWIRE_SR3, 0); 450 clk_disable(uwire->ck); 451 spi_master_put(uwire->bitbang.master); 452 } 453 454 static int uwire_probe(struct platform_device *pdev) 455 { 456 struct spi_master *master; 457 struct uwire_spi *uwire; 458 int status; 459 460 master = spi_alloc_master(&pdev->dev, sizeof *uwire); 461 if (!master) 462 return -ENODEV; 463 464 uwire = spi_master_get_devdata(master); 465 466 uwire_base = devm_ioremap(&pdev->dev, UWIRE_BASE_PHYS, UWIRE_IO_SIZE); 467 if (!uwire_base) { 468 dev_dbg(&pdev->dev, "can't ioremap UWIRE\n"); 469 spi_master_put(master); 470 return -ENOMEM; 471 } 472 473 platform_set_drvdata(pdev, uwire); 474 475 uwire->ck = devm_clk_get(&pdev->dev, "fck"); 476 if (IS_ERR(uwire->ck)) { 477 status = PTR_ERR(uwire->ck); 478 dev_dbg(&pdev->dev, "no functional clock?\n"); 479 spi_master_put(master); 480 return status; 481 } 482 clk_enable(uwire->ck); 483 484 if (cpu_is_omap7xx()) 485 uwire_idx_shift = 1; 486 else 487 uwire_idx_shift = 2; 488 489 uwire_write_reg(UWIRE_SR3, 1); 490 491 /* the spi->mode bits understood by this driver: */ 492 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; 493 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16); 494 master->flags = SPI_MASTER_HALF_DUPLEX; 495 496 master->bus_num = 2; /* "official" */ 497 master->num_chipselect = 4; 498 master->setup = uwire_setup; 499 master->cleanup = uwire_cleanup; 500 501 uwire->bitbang.master = master; 502 uwire->bitbang.chipselect = uwire_chipselect; 503 uwire->bitbang.setup_transfer = uwire_setup_transfer; 504 uwire->bitbang.txrx_bufs = uwire_txrx; 505 506 status = spi_bitbang_start(&uwire->bitbang); 507 if (status < 0) { 508 uwire_off(uwire); 509 } 510 return status; 511 } 512 513 static int uwire_remove(struct platform_device *pdev) 514 { 515 struct uwire_spi *uwire = platform_get_drvdata(pdev); 516 517 // FIXME remove all child devices, somewhere ... 518 519 spi_bitbang_stop(&uwire->bitbang); 520 uwire_off(uwire); 521 return 0; 522 } 523 524 /* work with hotplug and coldplug */ 525 MODULE_ALIAS("platform:omap_uwire"); 526 527 static struct platform_driver uwire_driver = { 528 .driver = { 529 .name = "omap_uwire", 530 .owner = THIS_MODULE, 531 }, 532 .probe = uwire_probe, 533 .remove = uwire_remove, 534 // suspend ... unuse ck 535 // resume ... use ck 536 }; 537 538 static int __init omap_uwire_init(void) 539 { 540 /* FIXME move these into the relevant board init code. also, include 541 * H3 support; it uses tsc2101 like H2 (on a different chipselect). 542 */ 543 544 if (machine_is_omap_h2()) { 545 /* defaults: W21 SDO, U18 SDI, V19 SCL */ 546 omap_cfg_reg(N14_1610_UWIRE_CS0); 547 omap_cfg_reg(N15_1610_UWIRE_CS1); 548 } 549 if (machine_is_omap_perseus2()) { 550 /* configure pins: MPU_UW_nSCS1, MPU_UW_SDO, MPU_UW_SCLK */ 551 int val = omap_readl(OMAP7XX_IO_CONF_9) & ~0x00EEE000; 552 omap_writel(val | 0x00AAA000, OMAP7XX_IO_CONF_9); 553 } 554 555 return platform_driver_register(&uwire_driver); 556 } 557 558 static void __exit omap_uwire_exit(void) 559 { 560 platform_driver_unregister(&uwire_driver); 561 } 562 563 subsys_initcall(omap_uwire_init); 564 module_exit(omap_uwire_exit); 565 566 MODULE_LICENSE("GPL"); 567 568