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 #include <linux/kernel.h> 33 #include <linux/init.h> 34 #include <linux/delay.h> 35 #include <linux/platform_device.h> 36 #include <linux/interrupt.h> 37 #include <linux/err.h> 38 #include <linux/clk.h> 39 #include <linux/slab.h> 40 #include <linux/device.h> 41 42 #include <linux/spi/spi.h> 43 #include <linux/spi/spi_bitbang.h> 44 #include <linux/module.h> 45 #include <linux/io.h> 46 47 #include <asm/mach-types.h> 48 #include <linux/soc/ti/omap1-io.h> 49 #include <linux/soc/ti/omap1-soc.h> 50 #include <linux/soc/ti/omap1-mux.h> 51 52 /* FIXME address is now a platform device resource, 53 * and irqs should show there too... 54 */ 55 #define UWIRE_BASE_PHYS 0xFFFB3000 56 57 /* uWire Registers: */ 58 #define UWIRE_IO_SIZE 0x20 59 #define UWIRE_TDR 0x00 60 #define UWIRE_RDR 0x00 61 #define UWIRE_CSR 0x01 62 #define UWIRE_SR1 0x02 63 #define UWIRE_SR2 0x03 64 #define UWIRE_SR3 0x04 65 #define UWIRE_SR4 0x05 66 #define UWIRE_SR5 0x06 67 68 /* CSR bits */ 69 #define RDRB (1 << 15) 70 #define CSRB (1 << 14) 71 #define START (1 << 13) 72 #define CS_CMD (1 << 12) 73 74 /* SR1 or SR2 bits */ 75 #define UWIRE_READ_FALLING_EDGE 0x0001 76 #define UWIRE_READ_RISING_EDGE 0x0000 77 #define UWIRE_WRITE_FALLING_EDGE 0x0000 78 #define UWIRE_WRITE_RISING_EDGE 0x0002 79 #define UWIRE_CS_ACTIVE_LOW 0x0000 80 #define UWIRE_CS_ACTIVE_HIGH 0x0004 81 #define UWIRE_FREQ_DIV_2 0x0000 82 #define UWIRE_FREQ_DIV_4 0x0008 83 #define UWIRE_FREQ_DIV_8 0x0010 84 #define UWIRE_CHK_READY 0x0020 85 #define UWIRE_CLK_INVERTED 0x0040 86 87 88 struct uwire_spi { 89 struct spi_bitbang bitbang; 90 struct clk *ck; 91 }; 92 93 struct uwire_state { 94 unsigned div1_idx; 95 }; 96 97 /* REVISIT compile time constant for idx_shift? */ 98 /* 99 * Or, put it in a structure which is used throughout the driver; 100 * that avoids having to issue two loads for each bit of static data. 101 */ 102 static unsigned int uwire_idx_shift = 2; 103 static void __iomem *uwire_base; 104 105 static inline void uwire_write_reg(int idx, u16 val) 106 { 107 __raw_writew(val, uwire_base + (idx << uwire_idx_shift)); 108 } 109 110 static inline u16 uwire_read_reg(int idx) 111 { 112 return __raw_readw(uwire_base + (idx << uwire_idx_shift)); 113 } 114 115 static inline void omap_uwire_configure_mode(u8 cs, unsigned long flags) 116 { 117 u16 w, val = 0; 118 int shift, reg; 119 120 if (flags & UWIRE_CLK_INVERTED) 121 val ^= 0x03; 122 val = flags & 0x3f; 123 if (cs & 1) 124 shift = 6; 125 else 126 shift = 0; 127 if (cs <= 1) 128 reg = UWIRE_SR1; 129 else 130 reg = UWIRE_SR2; 131 132 w = uwire_read_reg(reg); 133 w &= ~(0x3f << shift); 134 w |= val << shift; 135 uwire_write_reg(reg, w); 136 } 137 138 static int wait_uwire_csr_flag(u16 mask, u16 val, int might_not_catch) 139 { 140 u16 w; 141 int c = 0; 142 unsigned long max_jiffies = jiffies + HZ; 143 144 for (;;) { 145 w = uwire_read_reg(UWIRE_CSR); 146 if ((w & mask) == val) 147 break; 148 if (time_after(jiffies, max_jiffies)) { 149 printk(KERN_ERR "%s: timeout. reg=%#06x " 150 "mask=%#06x val=%#06x\n", 151 __func__, w, mask, val); 152 return -1; 153 } 154 c++; 155 if (might_not_catch && c > 64) 156 break; 157 } 158 return 0; 159 } 160 161 static void uwire_set_clk1_div(int div1_idx) 162 { 163 u16 w; 164 165 w = uwire_read_reg(UWIRE_SR3); 166 w &= ~(0x03 << 1); 167 w |= div1_idx << 1; 168 uwire_write_reg(UWIRE_SR3, w); 169 } 170 171 static void uwire_chipselect(struct spi_device *spi, int value) 172 { 173 struct uwire_state *ust = spi->controller_state; 174 u16 w; 175 int old_cs; 176 177 178 BUG_ON(wait_uwire_csr_flag(CSRB, 0, 0)); 179 180 w = uwire_read_reg(UWIRE_CSR); 181 old_cs = (w >> 10) & 0x03; 182 if (value == BITBANG_CS_INACTIVE || old_cs != spi_get_chipselect(spi, 0)) { 183 /* Deselect this CS, or the previous CS */ 184 w &= ~CS_CMD; 185 uwire_write_reg(UWIRE_CSR, w); 186 } 187 /* activate specfied chipselect */ 188 if (value == BITBANG_CS_ACTIVE) { 189 uwire_set_clk1_div(ust->div1_idx); 190 /* invert clock? */ 191 if (spi->mode & SPI_CPOL) 192 uwire_write_reg(UWIRE_SR4, 1); 193 else 194 uwire_write_reg(UWIRE_SR4, 0); 195 196 w = spi_get_chipselect(spi, 0) << 10; 197 w |= CS_CMD; 198 uwire_write_reg(UWIRE_CSR, w); 199 } 200 } 201 202 static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t) 203 { 204 unsigned len = t->len; 205 unsigned bits = t->bits_per_word; 206 unsigned bytes; 207 u16 val, w; 208 int status = 0; 209 210 if (!t->tx_buf && !t->rx_buf) 211 return 0; 212 213 w = spi_get_chipselect(spi, 0) << 10; 214 w |= CS_CMD; 215 216 if (t->tx_buf) { 217 const u8 *buf = t->tx_buf; 218 219 /* NOTE: DMA could be used for TX transfers */ 220 221 /* write one or two bytes at a time */ 222 while (len >= 1) { 223 /* tx bit 15 is first sent; we byteswap multibyte words 224 * (msb-first) on the way out from memory. 225 */ 226 val = *buf++; 227 if (bits > 8) { 228 bytes = 2; 229 val |= *buf++ << 8; 230 } else 231 bytes = 1; 232 val <<= 16 - bits; 233 234 #ifdef VERBOSE 235 pr_debug("%s: write-%d =%04x\n", 236 dev_name(&spi->dev), bits, val); 237 #endif 238 if (wait_uwire_csr_flag(CSRB, 0, 0)) 239 goto eio; 240 241 uwire_write_reg(UWIRE_TDR, val); 242 243 /* start write */ 244 val = START | w | (bits << 5); 245 246 uwire_write_reg(UWIRE_CSR, val); 247 len -= bytes; 248 249 /* Wait till write actually starts. 250 * This is needed with MPU clock 60+ MHz. 251 * REVISIT: we may not have time to catch it... 252 */ 253 if (wait_uwire_csr_flag(CSRB, CSRB, 1)) 254 goto eio; 255 256 status += bytes; 257 } 258 259 /* REVISIT: save this for later to get more i/o overlap */ 260 if (wait_uwire_csr_flag(CSRB, 0, 0)) 261 goto eio; 262 263 } else if (t->rx_buf) { 264 u8 *buf = t->rx_buf; 265 266 /* read one or two bytes at a time */ 267 while (len) { 268 if (bits > 8) { 269 bytes = 2; 270 } else 271 bytes = 1; 272 273 /* start read */ 274 val = START | w | (bits << 0); 275 uwire_write_reg(UWIRE_CSR, val); 276 len -= bytes; 277 278 /* Wait till read actually starts */ 279 (void) wait_uwire_csr_flag(CSRB, CSRB, 1); 280 281 if (wait_uwire_csr_flag(RDRB | CSRB, 282 RDRB, 0)) 283 goto eio; 284 285 /* rx bit 0 is last received; multibyte words will 286 * be properly byteswapped on the way to memory. 287 */ 288 val = uwire_read_reg(UWIRE_RDR); 289 val &= (1 << bits) - 1; 290 *buf++ = (u8) val; 291 if (bytes == 2) 292 *buf++ = val >> 8; 293 status += bytes; 294 #ifdef VERBOSE 295 pr_debug("%s: read-%d =%04x\n", 296 dev_name(&spi->dev), bits, val); 297 #endif 298 299 } 300 } 301 return status; 302 eio: 303 return -EIO; 304 } 305 306 static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t) 307 { 308 struct uwire_state *ust = spi->controller_state; 309 struct uwire_spi *uwire; 310 unsigned flags = 0; 311 unsigned hz; 312 unsigned long rate; 313 int div1_idx; 314 int div1; 315 int div2; 316 int status; 317 318 uwire = spi_controller_get_devdata(spi->controller); 319 320 /* mode 0..3, clock inverted separately; 321 * standard nCS signaling; 322 * don't treat DI=high as "not ready" 323 */ 324 if (spi->mode & SPI_CS_HIGH) 325 flags |= UWIRE_CS_ACTIVE_HIGH; 326 327 if (spi->mode & SPI_CPOL) 328 flags |= UWIRE_CLK_INVERTED; 329 330 switch (spi->mode & SPI_MODE_X_MASK) { 331 case SPI_MODE_0: 332 case SPI_MODE_3: 333 flags |= UWIRE_WRITE_FALLING_EDGE | UWIRE_READ_RISING_EDGE; 334 break; 335 case SPI_MODE_1: 336 case SPI_MODE_2: 337 flags |= UWIRE_WRITE_RISING_EDGE | UWIRE_READ_FALLING_EDGE; 338 break; 339 } 340 341 /* assume it's already enabled */ 342 rate = clk_get_rate(uwire->ck); 343 344 if (t != NULL) 345 hz = t->speed_hz; 346 else 347 hz = spi->max_speed_hz; 348 349 if (!hz) { 350 pr_debug("%s: zero speed?\n", dev_name(&spi->dev)); 351 status = -EINVAL; 352 goto done; 353 } 354 355 /* F_INT = mpu_xor_clk / DIV1 */ 356 for (div1_idx = 0; div1_idx < 4; div1_idx++) { 357 switch (div1_idx) { 358 case 0: 359 div1 = 2; 360 break; 361 case 1: 362 div1 = 4; 363 break; 364 case 2: 365 div1 = 7; 366 break; 367 default: 368 case 3: 369 div1 = 10; 370 break; 371 } 372 div2 = (rate / div1 + hz - 1) / hz; 373 if (div2 <= 8) 374 break; 375 } 376 if (div1_idx == 4) { 377 pr_debug("%s: lowest clock %ld, need %d\n", 378 dev_name(&spi->dev), rate / 10 / 8, hz); 379 status = -EDOM; 380 goto done; 381 } 382 383 /* we have to cache this and reset in uwire_chipselect as this is a 384 * global parameter and another uwire device can change it under 385 * us */ 386 ust->div1_idx = div1_idx; 387 uwire_set_clk1_div(div1_idx); 388 389 rate /= div1; 390 391 switch (div2) { 392 case 0: 393 case 1: 394 case 2: 395 flags |= UWIRE_FREQ_DIV_2; 396 rate /= 2; 397 break; 398 case 3: 399 case 4: 400 flags |= UWIRE_FREQ_DIV_4; 401 rate /= 4; 402 break; 403 case 5: 404 case 6: 405 case 7: 406 case 8: 407 flags |= UWIRE_FREQ_DIV_8; 408 rate /= 8; 409 break; 410 } 411 omap_uwire_configure_mode(spi_get_chipselect(spi, 0), flags); 412 pr_debug("%s: uwire flags %02x, armxor %lu KHz, SCK %lu KHz\n", 413 __func__, flags, 414 clk_get_rate(uwire->ck) / 1000, 415 rate / 1000); 416 status = 0; 417 done: 418 return status; 419 } 420 421 static int uwire_setup(struct spi_device *spi) 422 { 423 struct uwire_state *ust = spi->controller_state; 424 bool initial_setup = false; 425 int status; 426 427 if (ust == NULL) { 428 ust = kzalloc(sizeof(*ust), GFP_KERNEL); 429 if (ust == NULL) 430 return -ENOMEM; 431 spi->controller_state = ust; 432 initial_setup = true; 433 } 434 435 status = uwire_setup_transfer(spi, NULL); 436 if (status && initial_setup) 437 kfree(ust); 438 439 return status; 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_unprepare(uwire->ck); 451 spi_controller_put(uwire->bitbang.ctlr); 452 } 453 454 static int uwire_probe(struct platform_device *pdev) 455 { 456 struct spi_controller *host; 457 struct uwire_spi *uwire; 458 int status; 459 460 host = spi_alloc_host(&pdev->dev, sizeof(*uwire)); 461 if (!host) 462 return -ENODEV; 463 464 uwire = spi_controller_get_devdata(host); 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_controller_put(host); 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_controller_put(host); 480 return status; 481 } 482 clk_prepare_enable(uwire->ck); 483 484 uwire_write_reg(UWIRE_SR3, 1); 485 486 /* the spi->mode bits understood by this driver: */ 487 host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; 488 host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16); 489 host->flags = SPI_CONTROLLER_HALF_DUPLEX; 490 491 host->bus_num = 2; /* "official" */ 492 host->num_chipselect = 4; 493 host->setup = uwire_setup; 494 host->cleanup = uwire_cleanup; 495 496 uwire->bitbang.ctlr = host; 497 uwire->bitbang.chipselect = uwire_chipselect; 498 uwire->bitbang.setup_transfer = uwire_setup_transfer; 499 uwire->bitbang.txrx_bufs = uwire_txrx; 500 501 status = spi_bitbang_start(&uwire->bitbang); 502 if (status < 0) { 503 uwire_off(uwire); 504 } 505 return status; 506 } 507 508 static void uwire_remove(struct platform_device *pdev) 509 { 510 struct uwire_spi *uwire = platform_get_drvdata(pdev); 511 512 // FIXME remove all child devices, somewhere ... 513 514 spi_bitbang_stop(&uwire->bitbang); 515 uwire_off(uwire); 516 } 517 518 /* work with hotplug and coldplug */ 519 MODULE_ALIAS("platform:omap_uwire"); 520 521 static struct platform_driver uwire_driver = { 522 .driver = { 523 .name = "omap_uwire", 524 }, 525 .probe = uwire_probe, 526 .remove_new = uwire_remove, 527 // suspend ... unuse ck 528 // resume ... use ck 529 }; 530 531 static int __init omap_uwire_init(void) 532 { 533 return platform_driver_register(&uwire_driver); 534 } 535 536 static void __exit omap_uwire_exit(void) 537 { 538 platform_driver_unregister(&uwire_driver); 539 } 540 541 subsys_initcall(omap_uwire_init); 542 module_exit(omap_uwire_exit); 543 544 MODULE_DESCRIPTION("MicroWire interface driver for OMAP"); 545 MODULE_LICENSE("GPL"); 546 547