1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * MPC512x PSC in SPI mode driver. 4 * 5 * Copyright (C) 2007,2008 Freescale Semiconductor Inc. 6 * Original port from 52xx driver: 7 * Hongjun Chen <hong-jun.chen@freescale.com> 8 * 9 * Fork of mpc52xx_psc_spi.c: 10 * Copyright (C) 2006 TOPTICA Photonics AG., Dragos Carp 11 */ 12 13 #include <linux/module.h> 14 #include <linux/kernel.h> 15 #include <linux/errno.h> 16 #include <linux/interrupt.h> 17 #include <linux/of_address.h> 18 #include <linux/of_irq.h> 19 #include <linux/of_platform.h> 20 #include <linux/completion.h> 21 #include <linux/io.h> 22 #include <linux/delay.h> 23 #include <linux/clk.h> 24 #include <linux/spi/spi.h> 25 #include <linux/fsl_devices.h> 26 #include <linux/gpio.h> 27 #include <asm/mpc52xx_psc.h> 28 29 enum { 30 TYPE_MPC5121, 31 TYPE_MPC5125, 32 }; 33 34 /* 35 * This macro abstracts the differences in the PSC register layout between 36 * MPC5121 (which uses a struct mpc52xx_psc) and MPC5125 (using mpc5125_psc). 37 */ 38 #define psc_addr(mps, regname) ({ \ 39 void *__ret = NULL; \ 40 switch (mps->type) { \ 41 case TYPE_MPC5121: { \ 42 struct mpc52xx_psc __iomem *psc = mps->psc; \ 43 __ret = &psc->regname; \ 44 }; \ 45 break; \ 46 case TYPE_MPC5125: { \ 47 struct mpc5125_psc __iomem *psc = mps->psc; \ 48 __ret = &psc->regname; \ 49 }; \ 50 break; \ 51 } \ 52 __ret; }) 53 54 struct mpc512x_psc_spi { 55 void (*cs_control)(struct spi_device *spi, bool on); 56 57 /* driver internal data */ 58 int type; 59 void __iomem *psc; 60 struct mpc512x_psc_fifo __iomem *fifo; 61 unsigned int irq; 62 u8 bits_per_word; 63 struct clk *clk_mclk; 64 struct clk *clk_ipg; 65 u32 mclk_rate; 66 67 struct completion txisrdone; 68 }; 69 70 /* controller state */ 71 struct mpc512x_psc_spi_cs { 72 int bits_per_word; 73 int speed_hz; 74 }; 75 76 /* set clock freq, clock ramp, bits per work 77 * if t is NULL then reset the values to the default values 78 */ 79 static int mpc512x_psc_spi_transfer_setup(struct spi_device *spi, 80 struct spi_transfer *t) 81 { 82 struct mpc512x_psc_spi_cs *cs = spi->controller_state; 83 84 cs->speed_hz = (t && t->speed_hz) 85 ? t->speed_hz : spi->max_speed_hz; 86 cs->bits_per_word = (t && t->bits_per_word) 87 ? t->bits_per_word : spi->bits_per_word; 88 cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8; 89 return 0; 90 } 91 92 static void mpc512x_psc_spi_activate_cs(struct spi_device *spi) 93 { 94 struct mpc512x_psc_spi_cs *cs = spi->controller_state; 95 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master); 96 u32 sicr; 97 u32 ccr; 98 int speed; 99 u16 bclkdiv; 100 101 sicr = in_be32(psc_addr(mps, sicr)); 102 103 /* Set clock phase and polarity */ 104 if (spi->mode & SPI_CPHA) 105 sicr |= 0x00001000; 106 else 107 sicr &= ~0x00001000; 108 109 if (spi->mode & SPI_CPOL) 110 sicr |= 0x00002000; 111 else 112 sicr &= ~0x00002000; 113 114 if (spi->mode & SPI_LSB_FIRST) 115 sicr |= 0x10000000; 116 else 117 sicr &= ~0x10000000; 118 out_be32(psc_addr(mps, sicr), sicr); 119 120 ccr = in_be32(psc_addr(mps, ccr)); 121 ccr &= 0xFF000000; 122 speed = cs->speed_hz; 123 if (!speed) 124 speed = 1000000; /* default 1MHz */ 125 bclkdiv = (mps->mclk_rate / speed) - 1; 126 127 ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8)); 128 out_be32(psc_addr(mps, ccr), ccr); 129 mps->bits_per_word = cs->bits_per_word; 130 131 if (mps->cs_control && gpio_is_valid(spi->cs_gpio)) 132 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0); 133 } 134 135 static void mpc512x_psc_spi_deactivate_cs(struct spi_device *spi) 136 { 137 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master); 138 139 if (mps->cs_control && gpio_is_valid(spi->cs_gpio)) 140 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1); 141 142 } 143 144 /* extract and scale size field in txsz or rxsz */ 145 #define MPC512x_PSC_FIFO_SZ(sz) ((sz & 0x7ff) << 2); 146 147 #define EOFBYTE 1 148 149 static int mpc512x_psc_spi_transfer_rxtx(struct spi_device *spi, 150 struct spi_transfer *t) 151 { 152 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master); 153 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo; 154 size_t tx_len = t->len; 155 size_t rx_len = t->len; 156 u8 *tx_buf = (u8 *)t->tx_buf; 157 u8 *rx_buf = (u8 *)t->rx_buf; 158 159 if (!tx_buf && !rx_buf && t->len) 160 return -EINVAL; 161 162 while (rx_len || tx_len) { 163 size_t txcount; 164 u8 data; 165 size_t fifosz; 166 size_t rxcount; 167 int rxtries; 168 169 /* 170 * send the TX bytes in as large a chunk as possible 171 * but neither exceed the TX nor the RX FIFOs 172 */ 173 fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->txsz)); 174 txcount = min(fifosz, tx_len); 175 fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->rxsz)); 176 fifosz -= in_be32(&fifo->rxcnt) + 1; 177 txcount = min(fifosz, txcount); 178 if (txcount) { 179 180 /* fill the TX FIFO */ 181 while (txcount-- > 0) { 182 data = tx_buf ? *tx_buf++ : 0; 183 if (tx_len == EOFBYTE && t->cs_change) 184 setbits32(&fifo->txcmd, 185 MPC512x_PSC_FIFO_EOF); 186 out_8(&fifo->txdata_8, data); 187 tx_len--; 188 } 189 190 /* have the ISR trigger when the TX FIFO is empty */ 191 reinit_completion(&mps->txisrdone); 192 out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY); 193 out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY); 194 wait_for_completion(&mps->txisrdone); 195 } 196 197 /* 198 * consume as much RX data as the FIFO holds, while we 199 * iterate over the transfer's TX data length 200 * 201 * only insist in draining all the remaining RX bytes 202 * when the TX bytes were exhausted (that's at the very 203 * end of this transfer, not when still iterating over 204 * the transfer's chunks) 205 */ 206 rxtries = 50; 207 do { 208 209 /* 210 * grab whatever was in the FIFO when we started 211 * looking, don't bother fetching what was added to 212 * the FIFO while we read from it -- we'll return 213 * here eventually and prefer sending out remaining 214 * TX data 215 */ 216 fifosz = in_be32(&fifo->rxcnt); 217 rxcount = min(fifosz, rx_len); 218 while (rxcount-- > 0) { 219 data = in_8(&fifo->rxdata_8); 220 if (rx_buf) 221 *rx_buf++ = data; 222 rx_len--; 223 } 224 225 /* 226 * come back later if there still is TX data to send, 227 * bail out of the RX drain loop if all of the TX data 228 * was sent and all of the RX data was received (i.e. 229 * when the transmission has completed) 230 */ 231 if (tx_len) 232 break; 233 if (!rx_len) 234 break; 235 236 /* 237 * TX data transmission has completed while RX data 238 * is still pending -- that's a transient situation 239 * which depends on wire speed and specific 240 * hardware implementation details (buffering) yet 241 * should resolve very quickly 242 * 243 * just yield for a moment to not hog the CPU for 244 * too long when running SPI at low speed 245 * 246 * the timeout range is rather arbitrary and tries 247 * to balance throughput against system load; the 248 * chosen values result in a minimal timeout of 50 249 * times 10us and thus work at speeds as low as 250 * some 20kbps, while the maximum timeout at the 251 * transfer's end could be 5ms _if_ nothing else 252 * ticks in the system _and_ RX data still wasn't 253 * received, which only occurs in situations that 254 * are exceptional; removing the unpredictability 255 * of the timeout either decreases throughput 256 * (longer timeouts), or puts more load on the 257 * system (fixed short timeouts) or requires the 258 * use of a timeout API instead of a counter and an 259 * unknown inner delay 260 */ 261 usleep_range(10, 100); 262 263 } while (--rxtries > 0); 264 if (!tx_len && rx_len && !rxtries) { 265 /* 266 * not enough RX bytes even after several retries 267 * and the resulting rather long timeout? 268 */ 269 rxcount = in_be32(&fifo->rxcnt); 270 dev_warn(&spi->dev, 271 "short xfer, missing %zd RX bytes, FIFO level %zd\n", 272 rx_len, rxcount); 273 } 274 275 /* 276 * drain and drop RX data which "should not be there" in 277 * the first place, for undisturbed transmission this turns 278 * into a NOP (except for the FIFO level fetch) 279 */ 280 if (!tx_len && !rx_len) { 281 while (in_be32(&fifo->rxcnt)) 282 in_8(&fifo->rxdata_8); 283 } 284 285 } 286 return 0; 287 } 288 289 static int mpc512x_psc_spi_msg_xfer(struct spi_master *master, 290 struct spi_message *m) 291 { 292 struct spi_device *spi; 293 unsigned cs_change; 294 int status; 295 struct spi_transfer *t; 296 297 spi = m->spi; 298 cs_change = 1; 299 status = 0; 300 list_for_each_entry(t, &m->transfers, transfer_list) { 301 status = mpc512x_psc_spi_transfer_setup(spi, t); 302 if (status < 0) 303 break; 304 305 if (cs_change) 306 mpc512x_psc_spi_activate_cs(spi); 307 cs_change = t->cs_change; 308 309 status = mpc512x_psc_spi_transfer_rxtx(spi, t); 310 if (status) 311 break; 312 m->actual_length += t->len; 313 314 spi_transfer_delay_exec(t); 315 316 if (cs_change) 317 mpc512x_psc_spi_deactivate_cs(spi); 318 } 319 320 m->status = status; 321 if (m->complete) 322 m->complete(m->context); 323 324 if (status || !cs_change) 325 mpc512x_psc_spi_deactivate_cs(spi); 326 327 mpc512x_psc_spi_transfer_setup(spi, NULL); 328 329 spi_finalize_current_message(master); 330 return status; 331 } 332 333 static int mpc512x_psc_spi_prep_xfer_hw(struct spi_master *master) 334 { 335 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master); 336 337 dev_dbg(&master->dev, "%s()\n", __func__); 338 339 /* Zero MR2 */ 340 in_8(psc_addr(mps, mr2)); 341 out_8(psc_addr(mps, mr2), 0x0); 342 343 /* enable transmitter/receiver */ 344 out_8(psc_addr(mps, command), MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE); 345 346 return 0; 347 } 348 349 static int mpc512x_psc_spi_unprep_xfer_hw(struct spi_master *master) 350 { 351 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master); 352 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo; 353 354 dev_dbg(&master->dev, "%s()\n", __func__); 355 356 /* disable transmitter/receiver and fifo interrupt */ 357 out_8(psc_addr(mps, command), MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE); 358 out_be32(&fifo->tximr, 0); 359 360 return 0; 361 } 362 363 static int mpc512x_psc_spi_setup(struct spi_device *spi) 364 { 365 struct mpc512x_psc_spi_cs *cs = spi->controller_state; 366 int ret; 367 368 if (spi->bits_per_word % 8) 369 return -EINVAL; 370 371 if (!cs) { 372 cs = kzalloc(sizeof(*cs), GFP_KERNEL); 373 if (!cs) 374 return -ENOMEM; 375 376 if (gpio_is_valid(spi->cs_gpio)) { 377 ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev)); 378 if (ret) { 379 dev_err(&spi->dev, "can't get CS gpio: %d\n", 380 ret); 381 kfree(cs); 382 return ret; 383 } 384 gpio_direction_output(spi->cs_gpio, 385 spi->mode & SPI_CS_HIGH ? 0 : 1); 386 } 387 388 spi->controller_state = cs; 389 } 390 391 cs->bits_per_word = spi->bits_per_word; 392 cs->speed_hz = spi->max_speed_hz; 393 394 return 0; 395 } 396 397 static void mpc512x_psc_spi_cleanup(struct spi_device *spi) 398 { 399 if (gpio_is_valid(spi->cs_gpio)) 400 gpio_free(spi->cs_gpio); 401 kfree(spi->controller_state); 402 } 403 404 static int mpc512x_psc_spi_port_config(struct spi_master *master, 405 struct mpc512x_psc_spi *mps) 406 { 407 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo; 408 u32 sicr; 409 u32 ccr; 410 int speed; 411 u16 bclkdiv; 412 413 /* Reset the PSC into a known state */ 414 out_8(psc_addr(mps, command), MPC52xx_PSC_RST_RX); 415 out_8(psc_addr(mps, command), MPC52xx_PSC_RST_TX); 416 out_8(psc_addr(mps, command), MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE); 417 418 /* Disable psc interrupts all useful interrupts are in fifo */ 419 out_be16(psc_addr(mps, isr_imr.imr), 0); 420 421 /* Disable fifo interrupts, will be enabled later */ 422 out_be32(&fifo->tximr, 0); 423 out_be32(&fifo->rximr, 0); 424 425 /* Setup fifo slice address and size */ 426 /*out_be32(&fifo->txsz, 0x0fe00004);*/ 427 /*out_be32(&fifo->rxsz, 0x0ff00004);*/ 428 429 sicr = 0x01000000 | /* SIM = 0001 -- 8 bit */ 430 0x00800000 | /* GenClk = 1 -- internal clk */ 431 0x00008000 | /* SPI = 1 */ 432 0x00004000 | /* MSTR = 1 -- SPI master */ 433 0x00000800; /* UseEOF = 1 -- SS low until EOF */ 434 435 out_be32(psc_addr(mps, sicr), sicr); 436 437 ccr = in_be32(psc_addr(mps, ccr)); 438 ccr &= 0xFF000000; 439 speed = 1000000; /* default 1MHz */ 440 bclkdiv = (mps->mclk_rate / speed) - 1; 441 ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8)); 442 out_be32(psc_addr(mps, ccr), ccr); 443 444 /* Set 2ms DTL delay */ 445 out_8(psc_addr(mps, ctur), 0x00); 446 out_8(psc_addr(mps, ctlr), 0x82); 447 448 /* we don't use the alarms */ 449 out_be32(&fifo->rxalarm, 0xfff); 450 out_be32(&fifo->txalarm, 0); 451 452 /* Enable FIFO slices for Rx/Tx */ 453 out_be32(&fifo->rxcmd, 454 MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA); 455 out_be32(&fifo->txcmd, 456 MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA); 457 458 mps->bits_per_word = 8; 459 460 return 0; 461 } 462 463 static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id) 464 { 465 struct mpc512x_psc_spi *mps = (struct mpc512x_psc_spi *)dev_id; 466 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo; 467 468 /* clear interrupt and wake up the rx/tx routine */ 469 if (in_be32(&fifo->txisr) & 470 in_be32(&fifo->tximr) & MPC512x_PSC_FIFO_EMPTY) { 471 out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY); 472 out_be32(&fifo->tximr, 0); 473 complete(&mps->txisrdone); 474 return IRQ_HANDLED; 475 } 476 return IRQ_NONE; 477 } 478 479 static void mpc512x_spi_cs_control(struct spi_device *spi, bool onoff) 480 { 481 gpio_set_value(spi->cs_gpio, onoff); 482 } 483 484 static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr, 485 u32 size, unsigned int irq) 486 { 487 struct fsl_spi_platform_data *pdata = dev_get_platdata(dev); 488 struct mpc512x_psc_spi *mps; 489 struct spi_master *master; 490 int ret; 491 void *tempp; 492 struct clk *clk; 493 494 master = spi_alloc_master(dev, sizeof(*mps)); 495 if (master == NULL) 496 return -ENOMEM; 497 498 dev_set_drvdata(dev, master); 499 mps = spi_master_get_devdata(master); 500 mps->type = (int)of_device_get_match_data(dev); 501 mps->irq = irq; 502 503 if (pdata == NULL) { 504 mps->cs_control = mpc512x_spi_cs_control; 505 } else { 506 mps->cs_control = pdata->cs_control; 507 master->bus_num = pdata->bus_num; 508 master->num_chipselect = pdata->max_chipselect; 509 } 510 511 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST; 512 master->setup = mpc512x_psc_spi_setup; 513 master->prepare_transfer_hardware = mpc512x_psc_spi_prep_xfer_hw; 514 master->transfer_one_message = mpc512x_psc_spi_msg_xfer; 515 master->unprepare_transfer_hardware = mpc512x_psc_spi_unprep_xfer_hw; 516 master->cleanup = mpc512x_psc_spi_cleanup; 517 master->dev.of_node = dev->of_node; 518 519 tempp = devm_ioremap(dev, regaddr, size); 520 if (!tempp) { 521 dev_err(dev, "could not ioremap I/O port range\n"); 522 ret = -EFAULT; 523 goto free_master; 524 } 525 mps->psc = tempp; 526 mps->fifo = 527 (struct mpc512x_psc_fifo *)(tempp + sizeof(struct mpc52xx_psc)); 528 ret = devm_request_irq(dev, mps->irq, mpc512x_psc_spi_isr, IRQF_SHARED, 529 "mpc512x-psc-spi", mps); 530 if (ret) 531 goto free_master; 532 init_completion(&mps->txisrdone); 533 534 clk = devm_clk_get(dev, "mclk"); 535 if (IS_ERR(clk)) { 536 ret = PTR_ERR(clk); 537 goto free_master; 538 } 539 ret = clk_prepare_enable(clk); 540 if (ret) 541 goto free_master; 542 mps->clk_mclk = clk; 543 mps->mclk_rate = clk_get_rate(clk); 544 545 clk = devm_clk_get(dev, "ipg"); 546 if (IS_ERR(clk)) { 547 ret = PTR_ERR(clk); 548 goto free_mclk_clock; 549 } 550 ret = clk_prepare_enable(clk); 551 if (ret) 552 goto free_mclk_clock; 553 mps->clk_ipg = clk; 554 555 ret = mpc512x_psc_spi_port_config(master, mps); 556 if (ret < 0) 557 goto free_ipg_clock; 558 559 ret = devm_spi_register_master(dev, master); 560 if (ret < 0) 561 goto free_ipg_clock; 562 563 return ret; 564 565 free_ipg_clock: 566 clk_disable_unprepare(mps->clk_ipg); 567 free_mclk_clock: 568 clk_disable_unprepare(mps->clk_mclk); 569 free_master: 570 spi_master_put(master); 571 572 return ret; 573 } 574 575 static int mpc512x_psc_spi_do_remove(struct device *dev) 576 { 577 struct spi_master *master = dev_get_drvdata(dev); 578 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master); 579 580 clk_disable_unprepare(mps->clk_mclk); 581 clk_disable_unprepare(mps->clk_ipg); 582 583 return 0; 584 } 585 586 static int mpc512x_psc_spi_of_probe(struct platform_device *op) 587 { 588 const u32 *regaddr_p; 589 u64 regaddr64, size64; 590 591 regaddr_p = of_get_address(op->dev.of_node, 0, &size64, NULL); 592 if (!regaddr_p) { 593 dev_err(&op->dev, "Invalid PSC address\n"); 594 return -EINVAL; 595 } 596 regaddr64 = of_translate_address(op->dev.of_node, regaddr_p); 597 598 return mpc512x_psc_spi_do_probe(&op->dev, (u32) regaddr64, (u32) size64, 599 irq_of_parse_and_map(op->dev.of_node, 0)); 600 } 601 602 static int mpc512x_psc_spi_of_remove(struct platform_device *op) 603 { 604 return mpc512x_psc_spi_do_remove(&op->dev); 605 } 606 607 static const struct of_device_id mpc512x_psc_spi_of_match[] = { 608 { .compatible = "fsl,mpc5121-psc-spi", .data = (void *)TYPE_MPC5121 }, 609 { .compatible = "fsl,mpc5125-psc-spi", .data = (void *)TYPE_MPC5125 }, 610 {}, 611 }; 612 613 MODULE_DEVICE_TABLE(of, mpc512x_psc_spi_of_match); 614 615 static struct platform_driver mpc512x_psc_spi_of_driver = { 616 .probe = mpc512x_psc_spi_of_probe, 617 .remove = mpc512x_psc_spi_of_remove, 618 .driver = { 619 .name = "mpc512x-psc-spi", 620 .of_match_table = mpc512x_psc_spi_of_match, 621 }, 622 }; 623 module_platform_driver(mpc512x_psc_spi_of_driver); 624 625 MODULE_AUTHOR("John Rigby"); 626 MODULE_DESCRIPTION("MPC512x PSC SPI Driver"); 627 MODULE_LICENSE("GPL"); 628