1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Microchip PIC32 SPI controller driver. 4 * 5 * Purna Chandra Mandal <purna.mandal@microchip.com> 6 * Copyright (c) 2016, Microchip Technology Inc. 7 */ 8 9 #include <linux/clk.h> 10 #include <linux/clkdev.h> 11 #include <linux/delay.h> 12 #include <linux/dmaengine.h> 13 #include <linux/dma-mapping.h> 14 #include <linux/highmem.h> 15 #include <linux/module.h> 16 #include <linux/io.h> 17 #include <linux/interrupt.h> 18 #include <linux/of.h> 19 #include <linux/of_irq.h> 20 #include <linux/of_gpio.h> 21 #include <linux/of_address.h> 22 #include <linux/platform_device.h> 23 #include <linux/spi/spi.h> 24 25 /* SPI controller registers */ 26 struct pic32_spi_regs { 27 u32 ctrl; 28 u32 ctrl_clr; 29 u32 ctrl_set; 30 u32 ctrl_inv; 31 u32 status; 32 u32 status_clr; 33 u32 status_set; 34 u32 status_inv; 35 u32 buf; 36 u32 dontuse[3]; 37 u32 baud; 38 u32 dontuse2[3]; 39 u32 ctrl2; 40 u32 ctrl2_clr; 41 u32 ctrl2_set; 42 u32 ctrl2_inv; 43 }; 44 45 /* Bit fields of SPI Control Register */ 46 #define CTRL_RX_INT_SHIFT 0 /* Rx interrupt generation */ 47 #define RX_FIFO_EMPTY 0 48 #define RX_FIFO_NOT_EMPTY 1 /* not empty */ 49 #define RX_FIFO_HALF_FULL 2 /* full by half or more */ 50 #define RX_FIFO_FULL 3 /* completely full */ 51 52 #define CTRL_TX_INT_SHIFT 2 /* TX interrupt generation */ 53 #define TX_FIFO_ALL_EMPTY 0 /* completely empty */ 54 #define TX_FIFO_EMPTY 1 /* empty */ 55 #define TX_FIFO_HALF_EMPTY 2 /* empty by half or more */ 56 #define TX_FIFO_NOT_FULL 3 /* atleast one empty */ 57 58 #define CTRL_MSTEN BIT(5) /* enable master mode */ 59 #define CTRL_CKP BIT(6) /* active low */ 60 #define CTRL_CKE BIT(8) /* Tx on falling edge */ 61 #define CTRL_SMP BIT(9) /* Rx at middle or end of tx */ 62 #define CTRL_BPW_MASK 0x03 /* bits per word/sample */ 63 #define CTRL_BPW_SHIFT 10 64 #define PIC32_BPW_8 0 65 #define PIC32_BPW_16 1 66 #define PIC32_BPW_32 2 67 #define CTRL_SIDL BIT(13) /* sleep when idle */ 68 #define CTRL_ON BIT(15) /* enable macro */ 69 #define CTRL_ENHBUF BIT(16) /* enable enhanced buffering */ 70 #define CTRL_MCLKSEL BIT(23) /* select clock source */ 71 #define CTRL_MSSEN BIT(28) /* macro driven /SS */ 72 #define CTRL_FRMEN BIT(31) /* enable framing mode */ 73 74 /* Bit fields of SPI Status Register */ 75 #define STAT_RF_EMPTY BIT(5) /* RX Fifo empty */ 76 #define STAT_RX_OV BIT(6) /* err, s/w needs to clear */ 77 #define STAT_TX_UR BIT(8) /* UR in Framed SPI modes */ 78 #define STAT_FRM_ERR BIT(12) /* Multiple Frame Sync pulse */ 79 #define STAT_TF_LVL_MASK 0x1F 80 #define STAT_TF_LVL_SHIFT 16 81 #define STAT_RF_LVL_MASK 0x1F 82 #define STAT_RF_LVL_SHIFT 24 83 84 /* Bit fields of SPI Baud Register */ 85 #define BAUD_MASK 0x1ff 86 87 /* Bit fields of SPI Control2 Register */ 88 #define CTRL2_TX_UR_EN BIT(10) /* Enable int on Tx under-run */ 89 #define CTRL2_RX_OV_EN BIT(11) /* Enable int on Rx over-run */ 90 #define CTRL2_FRM_ERR_EN BIT(12) /* Enable frame err int */ 91 92 /* Minimum DMA transfer size */ 93 #define PIC32_DMA_LEN_MIN 64 94 95 struct pic32_spi { 96 dma_addr_t dma_base; 97 struct pic32_spi_regs __iomem *regs; 98 int fault_irq; 99 int rx_irq; 100 int tx_irq; 101 u32 fifo_n_byte; /* FIFO depth in bytes */ 102 struct clk *clk; 103 struct spi_master *master; 104 /* Current controller setting */ 105 u32 speed_hz; /* spi-clk rate */ 106 u32 mode; 107 u32 bits_per_word; 108 u32 fifo_n_elm; /* FIFO depth in words */ 109 #define PIC32F_DMA_PREP 0 /* DMA chnls configured */ 110 unsigned long flags; 111 /* Current transfer state */ 112 struct completion xfer_done; 113 /* PIO transfer specific */ 114 const void *tx; 115 const void *tx_end; 116 const void *rx; 117 const void *rx_end; 118 int len; 119 void (*rx_fifo)(struct pic32_spi *); 120 void (*tx_fifo)(struct pic32_spi *); 121 }; 122 123 static inline void pic32_spi_enable(struct pic32_spi *pic32s) 124 { 125 writel(CTRL_ON | CTRL_SIDL, &pic32s->regs->ctrl_set); 126 } 127 128 static inline void pic32_spi_disable(struct pic32_spi *pic32s) 129 { 130 writel(CTRL_ON | CTRL_SIDL, &pic32s->regs->ctrl_clr); 131 132 /* avoid SPI registers read/write at immediate next CPU clock */ 133 ndelay(20); 134 } 135 136 static void pic32_spi_set_clk_rate(struct pic32_spi *pic32s, u32 spi_ck) 137 { 138 u32 div; 139 140 /* div = (clk_in / 2 * spi_ck) - 1 */ 141 div = DIV_ROUND_CLOSEST(clk_get_rate(pic32s->clk), 2 * spi_ck) - 1; 142 143 writel(div & BAUD_MASK, &pic32s->regs->baud); 144 } 145 146 static inline u32 pic32_rx_fifo_level(struct pic32_spi *pic32s) 147 { 148 u32 sr = readl(&pic32s->regs->status); 149 150 return (sr >> STAT_RF_LVL_SHIFT) & STAT_RF_LVL_MASK; 151 } 152 153 static inline u32 pic32_tx_fifo_level(struct pic32_spi *pic32s) 154 { 155 u32 sr = readl(&pic32s->regs->status); 156 157 return (sr >> STAT_TF_LVL_SHIFT) & STAT_TF_LVL_MASK; 158 } 159 160 /* Return the max entries we can fill into tx fifo */ 161 static u32 pic32_tx_max(struct pic32_spi *pic32s, int n_bytes) 162 { 163 u32 tx_left, tx_room, rxtx_gap; 164 165 tx_left = (pic32s->tx_end - pic32s->tx) / n_bytes; 166 tx_room = pic32s->fifo_n_elm - pic32_tx_fifo_level(pic32s); 167 168 /* 169 * Another concern is about the tx/rx mismatch, we 170 * though to use (pic32s->fifo_n_byte - rxfl - txfl) as 171 * one maximum value for tx, but it doesn't cover the 172 * data which is out of tx/rx fifo and inside the 173 * shift registers. So a ctrl from sw point of 174 * view is taken. 175 */ 176 rxtx_gap = ((pic32s->rx_end - pic32s->rx) - 177 (pic32s->tx_end - pic32s->tx)) / n_bytes; 178 return min3(tx_left, tx_room, (u32)(pic32s->fifo_n_elm - rxtx_gap)); 179 } 180 181 /* Return the max entries we should read out of rx fifo */ 182 static u32 pic32_rx_max(struct pic32_spi *pic32s, int n_bytes) 183 { 184 u32 rx_left = (pic32s->rx_end - pic32s->rx) / n_bytes; 185 186 return min_t(u32, rx_left, pic32_rx_fifo_level(pic32s)); 187 } 188 189 #define BUILD_SPI_FIFO_RW(__name, __type, __bwl) \ 190 static void pic32_spi_rx_##__name(struct pic32_spi *pic32s) \ 191 { \ 192 __type v; \ 193 u32 mx = pic32_rx_max(pic32s, sizeof(__type)); \ 194 for (; mx; mx--) { \ 195 v = read##__bwl(&pic32s->regs->buf); \ 196 if (pic32s->rx_end - pic32s->len) \ 197 *(__type *)(pic32s->rx) = v; \ 198 pic32s->rx += sizeof(__type); \ 199 } \ 200 } \ 201 \ 202 static void pic32_spi_tx_##__name(struct pic32_spi *pic32s) \ 203 { \ 204 __type v; \ 205 u32 mx = pic32_tx_max(pic32s, sizeof(__type)); \ 206 for (; mx ; mx--) { \ 207 v = (__type)~0U; \ 208 if (pic32s->tx_end - pic32s->len) \ 209 v = *(__type *)(pic32s->tx); \ 210 write##__bwl(v, &pic32s->regs->buf); \ 211 pic32s->tx += sizeof(__type); \ 212 } \ 213 } 214 215 BUILD_SPI_FIFO_RW(byte, u8, b); 216 BUILD_SPI_FIFO_RW(word, u16, w); 217 BUILD_SPI_FIFO_RW(dword, u32, l); 218 219 static void pic32_err_stop(struct pic32_spi *pic32s, const char *msg) 220 { 221 /* disable all interrupts */ 222 disable_irq_nosync(pic32s->fault_irq); 223 disable_irq_nosync(pic32s->rx_irq); 224 disable_irq_nosync(pic32s->tx_irq); 225 226 /* Show err message and abort xfer with err */ 227 dev_err(&pic32s->master->dev, "%s\n", msg); 228 if (pic32s->master->cur_msg) 229 pic32s->master->cur_msg->status = -EIO; 230 complete(&pic32s->xfer_done); 231 } 232 233 static irqreturn_t pic32_spi_fault_irq(int irq, void *dev_id) 234 { 235 struct pic32_spi *pic32s = dev_id; 236 u32 status; 237 238 status = readl(&pic32s->regs->status); 239 240 /* Error handling */ 241 if (status & (STAT_RX_OV | STAT_TX_UR)) { 242 writel(STAT_RX_OV, &pic32s->regs->status_clr); 243 writel(STAT_TX_UR, &pic32s->regs->status_clr); 244 pic32_err_stop(pic32s, "err_irq: fifo ov/ur-run\n"); 245 return IRQ_HANDLED; 246 } 247 248 if (status & STAT_FRM_ERR) { 249 pic32_err_stop(pic32s, "err_irq: frame error"); 250 return IRQ_HANDLED; 251 } 252 253 if (!pic32s->master->cur_msg) { 254 pic32_err_stop(pic32s, "err_irq: no mesg"); 255 return IRQ_NONE; 256 } 257 258 return IRQ_NONE; 259 } 260 261 static irqreturn_t pic32_spi_rx_irq(int irq, void *dev_id) 262 { 263 struct pic32_spi *pic32s = dev_id; 264 265 pic32s->rx_fifo(pic32s); 266 267 /* rx complete ? */ 268 if (pic32s->rx_end == pic32s->rx) { 269 /* disable all interrupts */ 270 disable_irq_nosync(pic32s->fault_irq); 271 disable_irq_nosync(pic32s->rx_irq); 272 273 /* complete current xfer */ 274 complete(&pic32s->xfer_done); 275 } 276 277 return IRQ_HANDLED; 278 } 279 280 static irqreturn_t pic32_spi_tx_irq(int irq, void *dev_id) 281 { 282 struct pic32_spi *pic32s = dev_id; 283 284 pic32s->tx_fifo(pic32s); 285 286 /* tx complete? disable tx interrupt */ 287 if (pic32s->tx_end == pic32s->tx) 288 disable_irq_nosync(pic32s->tx_irq); 289 290 return IRQ_HANDLED; 291 } 292 293 static void pic32_spi_dma_rx_notify(void *data) 294 { 295 struct pic32_spi *pic32s = data; 296 297 complete(&pic32s->xfer_done); 298 } 299 300 static int pic32_spi_dma_transfer(struct pic32_spi *pic32s, 301 struct spi_transfer *xfer) 302 { 303 struct spi_master *master = pic32s->master; 304 struct dma_async_tx_descriptor *desc_rx; 305 struct dma_async_tx_descriptor *desc_tx; 306 dma_cookie_t cookie; 307 int ret; 308 309 if (!master->dma_rx || !master->dma_tx) 310 return -ENODEV; 311 312 desc_rx = dmaengine_prep_slave_sg(master->dma_rx, 313 xfer->rx_sg.sgl, 314 xfer->rx_sg.nents, 315 DMA_DEV_TO_MEM, 316 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 317 if (!desc_rx) { 318 ret = -EINVAL; 319 goto err_dma; 320 } 321 322 desc_tx = dmaengine_prep_slave_sg(master->dma_tx, 323 xfer->tx_sg.sgl, 324 xfer->tx_sg.nents, 325 DMA_MEM_TO_DEV, 326 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 327 if (!desc_tx) { 328 ret = -EINVAL; 329 goto err_dma; 330 } 331 332 /* Put callback on the RX transfer, that should finish last */ 333 desc_rx->callback = pic32_spi_dma_rx_notify; 334 desc_rx->callback_param = pic32s; 335 336 cookie = dmaengine_submit(desc_rx); 337 ret = dma_submit_error(cookie); 338 if (ret) 339 goto err_dma; 340 341 cookie = dmaengine_submit(desc_tx); 342 ret = dma_submit_error(cookie); 343 if (ret) 344 goto err_dma_tx; 345 346 dma_async_issue_pending(master->dma_rx); 347 dma_async_issue_pending(master->dma_tx); 348 349 return 0; 350 351 err_dma_tx: 352 dmaengine_terminate_all(master->dma_rx); 353 err_dma: 354 return ret; 355 } 356 357 static int pic32_spi_dma_config(struct pic32_spi *pic32s, u32 dma_width) 358 { 359 int buf_offset = offsetof(struct pic32_spi_regs, buf); 360 struct spi_master *master = pic32s->master; 361 struct dma_slave_config cfg; 362 int ret; 363 364 memset(&cfg, 0, sizeof(cfg)); 365 cfg.device_fc = true; 366 cfg.src_addr = pic32s->dma_base + buf_offset; 367 cfg.dst_addr = pic32s->dma_base + buf_offset; 368 cfg.src_maxburst = pic32s->fifo_n_elm / 2; /* fill one-half */ 369 cfg.dst_maxburst = pic32s->fifo_n_elm / 2; /* drain one-half */ 370 cfg.src_addr_width = dma_width; 371 cfg.dst_addr_width = dma_width; 372 /* tx channel */ 373 cfg.direction = DMA_MEM_TO_DEV; 374 ret = dmaengine_slave_config(master->dma_tx, &cfg); 375 if (ret) { 376 dev_err(&master->dev, "tx channel setup failed\n"); 377 return ret; 378 } 379 /* rx channel */ 380 cfg.direction = DMA_DEV_TO_MEM; 381 ret = dmaengine_slave_config(master->dma_rx, &cfg); 382 if (ret) 383 dev_err(&master->dev, "rx channel setup failed\n"); 384 385 return ret; 386 } 387 388 static int pic32_spi_set_word_size(struct pic32_spi *pic32s, u8 bits_per_word) 389 { 390 enum dma_slave_buswidth dmawidth; 391 u32 buswidth, v; 392 393 switch (bits_per_word) { 394 case 8: 395 pic32s->rx_fifo = pic32_spi_rx_byte; 396 pic32s->tx_fifo = pic32_spi_tx_byte; 397 buswidth = PIC32_BPW_8; 398 dmawidth = DMA_SLAVE_BUSWIDTH_1_BYTE; 399 break; 400 case 16: 401 pic32s->rx_fifo = pic32_spi_rx_word; 402 pic32s->tx_fifo = pic32_spi_tx_word; 403 buswidth = PIC32_BPW_16; 404 dmawidth = DMA_SLAVE_BUSWIDTH_2_BYTES; 405 break; 406 case 32: 407 pic32s->rx_fifo = pic32_spi_rx_dword; 408 pic32s->tx_fifo = pic32_spi_tx_dword; 409 buswidth = PIC32_BPW_32; 410 dmawidth = DMA_SLAVE_BUSWIDTH_4_BYTES; 411 break; 412 default: 413 /* not supported */ 414 return -EINVAL; 415 } 416 417 /* calculate maximum number of words fifos can hold */ 418 pic32s->fifo_n_elm = DIV_ROUND_UP(pic32s->fifo_n_byte, 419 bits_per_word / 8); 420 /* set word size */ 421 v = readl(&pic32s->regs->ctrl); 422 v &= ~(CTRL_BPW_MASK << CTRL_BPW_SHIFT); 423 v |= buswidth << CTRL_BPW_SHIFT; 424 writel(v, &pic32s->regs->ctrl); 425 426 /* re-configure dma width, if required */ 427 if (test_bit(PIC32F_DMA_PREP, &pic32s->flags)) 428 pic32_spi_dma_config(pic32s, dmawidth); 429 430 return 0; 431 } 432 433 static int pic32_spi_prepare_hardware(struct spi_master *master) 434 { 435 struct pic32_spi *pic32s = spi_master_get_devdata(master); 436 437 pic32_spi_enable(pic32s); 438 439 return 0; 440 } 441 442 static int pic32_spi_prepare_message(struct spi_master *master, 443 struct spi_message *msg) 444 { 445 struct pic32_spi *pic32s = spi_master_get_devdata(master); 446 struct spi_device *spi = msg->spi; 447 u32 val; 448 449 /* set device specific bits_per_word */ 450 if (pic32s->bits_per_word != spi->bits_per_word) { 451 pic32_spi_set_word_size(pic32s, spi->bits_per_word); 452 pic32s->bits_per_word = spi->bits_per_word; 453 } 454 455 /* device specific speed change */ 456 if (pic32s->speed_hz != spi->max_speed_hz) { 457 pic32_spi_set_clk_rate(pic32s, spi->max_speed_hz); 458 pic32s->speed_hz = spi->max_speed_hz; 459 } 460 461 /* device specific mode change */ 462 if (pic32s->mode != spi->mode) { 463 val = readl(&pic32s->regs->ctrl); 464 /* active low */ 465 if (spi->mode & SPI_CPOL) 466 val |= CTRL_CKP; 467 else 468 val &= ~CTRL_CKP; 469 /* tx on rising edge */ 470 if (spi->mode & SPI_CPHA) 471 val &= ~CTRL_CKE; 472 else 473 val |= CTRL_CKE; 474 475 /* rx at end of tx */ 476 val |= CTRL_SMP; 477 writel(val, &pic32s->regs->ctrl); 478 pic32s->mode = spi->mode; 479 } 480 481 return 0; 482 } 483 484 static bool pic32_spi_can_dma(struct spi_master *master, 485 struct spi_device *spi, 486 struct spi_transfer *xfer) 487 { 488 struct pic32_spi *pic32s = spi_master_get_devdata(master); 489 490 /* skip using DMA on small size transfer to avoid overhead.*/ 491 return (xfer->len >= PIC32_DMA_LEN_MIN) && 492 test_bit(PIC32F_DMA_PREP, &pic32s->flags); 493 } 494 495 static int pic32_spi_one_transfer(struct spi_master *master, 496 struct spi_device *spi, 497 struct spi_transfer *transfer) 498 { 499 struct pic32_spi *pic32s; 500 bool dma_issued = false; 501 unsigned long timeout; 502 int ret; 503 504 pic32s = spi_master_get_devdata(master); 505 506 /* handle transfer specific word size change */ 507 if (transfer->bits_per_word && 508 (transfer->bits_per_word != pic32s->bits_per_word)) { 509 ret = pic32_spi_set_word_size(pic32s, transfer->bits_per_word); 510 if (ret) 511 return ret; 512 pic32s->bits_per_word = transfer->bits_per_word; 513 } 514 515 /* handle transfer specific speed change */ 516 if (transfer->speed_hz && (transfer->speed_hz != pic32s->speed_hz)) { 517 pic32_spi_set_clk_rate(pic32s, transfer->speed_hz); 518 pic32s->speed_hz = transfer->speed_hz; 519 } 520 521 reinit_completion(&pic32s->xfer_done); 522 523 /* transact by DMA mode */ 524 if (transfer->rx_sg.nents && transfer->tx_sg.nents) { 525 ret = pic32_spi_dma_transfer(pic32s, transfer); 526 if (ret) { 527 dev_err(&spi->dev, "dma submit error\n"); 528 return ret; 529 } 530 531 /* DMA issued */ 532 dma_issued = true; 533 } else { 534 /* set current transfer information */ 535 pic32s->tx = (const void *)transfer->tx_buf; 536 pic32s->rx = (const void *)transfer->rx_buf; 537 pic32s->tx_end = pic32s->tx + transfer->len; 538 pic32s->rx_end = pic32s->rx + transfer->len; 539 pic32s->len = transfer->len; 540 541 /* transact by interrupt driven PIO */ 542 enable_irq(pic32s->fault_irq); 543 enable_irq(pic32s->rx_irq); 544 enable_irq(pic32s->tx_irq); 545 } 546 547 /* wait for completion */ 548 timeout = wait_for_completion_timeout(&pic32s->xfer_done, 2 * HZ); 549 if (timeout == 0) { 550 dev_err(&spi->dev, "wait error/timedout\n"); 551 if (dma_issued) { 552 dmaengine_terminate_all(master->dma_rx); 553 dmaengine_terminate_all(master->dma_tx); 554 } 555 ret = -ETIMEDOUT; 556 } else { 557 ret = 0; 558 } 559 560 return ret; 561 } 562 563 static int pic32_spi_unprepare_message(struct spi_master *master, 564 struct spi_message *msg) 565 { 566 /* nothing to do */ 567 return 0; 568 } 569 570 static int pic32_spi_unprepare_hardware(struct spi_master *master) 571 { 572 struct pic32_spi *pic32s = spi_master_get_devdata(master); 573 574 pic32_spi_disable(pic32s); 575 576 return 0; 577 } 578 579 /* This may be called multiple times by same spi dev */ 580 static int pic32_spi_setup(struct spi_device *spi) 581 { 582 if (!spi->max_speed_hz) { 583 dev_err(&spi->dev, "No max speed HZ parameter\n"); 584 return -EINVAL; 585 } 586 587 /* PIC32 spi controller can drive /CS during transfer depending 588 * on tx fifo fill-level. /CS will stay asserted as long as TX 589 * fifo is non-empty, else will be deasserted indicating 590 * completion of the ongoing transfer. This might result into 591 * unreliable/erroneous SPI transactions. 592 * To avoid that we will always handle /CS by toggling GPIO. 593 */ 594 if (!spi->cs_gpiod) 595 return -EINVAL; 596 597 return 0; 598 } 599 600 static void pic32_spi_cleanup(struct spi_device *spi) 601 { 602 /* de-activate cs-gpio, gpiolib will handle inversion */ 603 gpiod_direction_output(spi->cs_gpiod, 0); 604 } 605 606 static int pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev) 607 { 608 struct spi_master *master = pic32s->master; 609 int ret = 0; 610 611 master->dma_rx = dma_request_chan(dev, "spi-rx"); 612 if (IS_ERR(master->dma_rx)) { 613 if (PTR_ERR(master->dma_rx) == -EPROBE_DEFER) 614 ret = -EPROBE_DEFER; 615 else 616 dev_warn(dev, "RX channel not found.\n"); 617 618 master->dma_rx = NULL; 619 goto out_err; 620 } 621 622 master->dma_tx = dma_request_chan(dev, "spi-tx"); 623 if (IS_ERR(master->dma_tx)) { 624 if (PTR_ERR(master->dma_tx) == -EPROBE_DEFER) 625 ret = -EPROBE_DEFER; 626 else 627 dev_warn(dev, "TX channel not found.\n"); 628 629 master->dma_tx = NULL; 630 goto out_err; 631 } 632 633 if (pic32_spi_dma_config(pic32s, DMA_SLAVE_BUSWIDTH_1_BYTE)) 634 goto out_err; 635 636 /* DMA chnls allocated and prepared */ 637 set_bit(PIC32F_DMA_PREP, &pic32s->flags); 638 639 return 0; 640 641 out_err: 642 if (master->dma_rx) { 643 dma_release_channel(master->dma_rx); 644 master->dma_rx = NULL; 645 } 646 647 if (master->dma_tx) { 648 dma_release_channel(master->dma_tx); 649 master->dma_tx = NULL; 650 } 651 652 return ret; 653 } 654 655 static void pic32_spi_dma_unprep(struct pic32_spi *pic32s) 656 { 657 if (!test_bit(PIC32F_DMA_PREP, &pic32s->flags)) 658 return; 659 660 clear_bit(PIC32F_DMA_PREP, &pic32s->flags); 661 if (pic32s->master->dma_rx) 662 dma_release_channel(pic32s->master->dma_rx); 663 664 if (pic32s->master->dma_tx) 665 dma_release_channel(pic32s->master->dma_tx); 666 } 667 668 static void pic32_spi_hw_init(struct pic32_spi *pic32s) 669 { 670 u32 ctrl; 671 672 /* disable hardware */ 673 pic32_spi_disable(pic32s); 674 675 ctrl = readl(&pic32s->regs->ctrl); 676 /* enable enhanced fifo of 128bit deep */ 677 ctrl |= CTRL_ENHBUF; 678 pic32s->fifo_n_byte = 16; 679 680 /* disable framing mode */ 681 ctrl &= ~CTRL_FRMEN; 682 683 /* enable master mode while disabled */ 684 ctrl |= CTRL_MSTEN; 685 686 /* set tx fifo threshold interrupt */ 687 ctrl &= ~(0x3 << CTRL_TX_INT_SHIFT); 688 ctrl |= (TX_FIFO_HALF_EMPTY << CTRL_TX_INT_SHIFT); 689 690 /* set rx fifo threshold interrupt */ 691 ctrl &= ~(0x3 << CTRL_RX_INT_SHIFT); 692 ctrl |= (RX_FIFO_NOT_EMPTY << CTRL_RX_INT_SHIFT); 693 694 /* select clk source */ 695 ctrl &= ~CTRL_MCLKSEL; 696 697 /* set manual /CS mode */ 698 ctrl &= ~CTRL_MSSEN; 699 700 writel(ctrl, &pic32s->regs->ctrl); 701 702 /* enable error reporting */ 703 ctrl = CTRL2_TX_UR_EN | CTRL2_RX_OV_EN | CTRL2_FRM_ERR_EN; 704 writel(ctrl, &pic32s->regs->ctrl2_set); 705 } 706 707 static int pic32_spi_hw_probe(struct platform_device *pdev, 708 struct pic32_spi *pic32s) 709 { 710 struct resource *mem; 711 int ret; 712 713 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 714 pic32s->regs = devm_ioremap_resource(&pdev->dev, mem); 715 if (IS_ERR(pic32s->regs)) 716 return PTR_ERR(pic32s->regs); 717 718 pic32s->dma_base = mem->start; 719 720 /* get irq resources: err-irq, rx-irq, tx-irq */ 721 pic32s->fault_irq = platform_get_irq_byname(pdev, "fault"); 722 if (pic32s->fault_irq < 0) 723 return pic32s->fault_irq; 724 725 pic32s->rx_irq = platform_get_irq_byname(pdev, "rx"); 726 if (pic32s->rx_irq < 0) 727 return pic32s->rx_irq; 728 729 pic32s->tx_irq = platform_get_irq_byname(pdev, "tx"); 730 if (pic32s->tx_irq < 0) 731 return pic32s->tx_irq; 732 733 /* get clock */ 734 pic32s->clk = devm_clk_get(&pdev->dev, "mck0"); 735 if (IS_ERR(pic32s->clk)) { 736 dev_err(&pdev->dev, "clk not found\n"); 737 ret = PTR_ERR(pic32s->clk); 738 goto err_unmap_mem; 739 } 740 741 ret = clk_prepare_enable(pic32s->clk); 742 if (ret) 743 goto err_unmap_mem; 744 745 pic32_spi_hw_init(pic32s); 746 747 return 0; 748 749 err_unmap_mem: 750 dev_err(&pdev->dev, "%s failed, err %d\n", __func__, ret); 751 return ret; 752 } 753 754 static int pic32_spi_probe(struct platform_device *pdev) 755 { 756 struct spi_master *master; 757 struct pic32_spi *pic32s; 758 int ret; 759 760 master = spi_alloc_master(&pdev->dev, sizeof(*pic32s)); 761 if (!master) 762 return -ENOMEM; 763 764 pic32s = spi_master_get_devdata(master); 765 pic32s->master = master; 766 767 ret = pic32_spi_hw_probe(pdev, pic32s); 768 if (ret) 769 goto err_master; 770 771 master->dev.of_node = pdev->dev.of_node; 772 master->mode_bits = SPI_MODE_3 | SPI_MODE_0 | SPI_CS_HIGH; 773 master->num_chipselect = 1; /* single chip-select */ 774 master->max_speed_hz = clk_get_rate(pic32s->clk); 775 master->setup = pic32_spi_setup; 776 master->cleanup = pic32_spi_cleanup; 777 master->flags = SPI_MASTER_MUST_TX | SPI_MASTER_MUST_RX; 778 master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16) | 779 SPI_BPW_MASK(32); 780 master->transfer_one = pic32_spi_one_transfer; 781 master->prepare_message = pic32_spi_prepare_message; 782 master->unprepare_message = pic32_spi_unprepare_message; 783 master->prepare_transfer_hardware = pic32_spi_prepare_hardware; 784 master->unprepare_transfer_hardware = pic32_spi_unprepare_hardware; 785 master->use_gpio_descriptors = true; 786 787 /* optional DMA support */ 788 ret = pic32_spi_dma_prep(pic32s, &pdev->dev); 789 if (ret) 790 goto err_bailout; 791 792 if (test_bit(PIC32F_DMA_PREP, &pic32s->flags)) 793 master->can_dma = pic32_spi_can_dma; 794 795 init_completion(&pic32s->xfer_done); 796 pic32s->mode = -1; 797 798 /* install irq handlers (with irq-disabled) */ 799 irq_set_status_flags(pic32s->fault_irq, IRQ_NOAUTOEN); 800 ret = devm_request_irq(&pdev->dev, pic32s->fault_irq, 801 pic32_spi_fault_irq, IRQF_NO_THREAD, 802 dev_name(&pdev->dev), pic32s); 803 if (ret < 0) { 804 dev_err(&pdev->dev, "request fault-irq %d\n", pic32s->rx_irq); 805 goto err_bailout; 806 } 807 808 /* receive interrupt handler */ 809 irq_set_status_flags(pic32s->rx_irq, IRQ_NOAUTOEN); 810 ret = devm_request_irq(&pdev->dev, pic32s->rx_irq, 811 pic32_spi_rx_irq, IRQF_NO_THREAD, 812 dev_name(&pdev->dev), pic32s); 813 if (ret < 0) { 814 dev_err(&pdev->dev, "request rx-irq %d\n", pic32s->rx_irq); 815 goto err_bailout; 816 } 817 818 /* transmit interrupt handler */ 819 irq_set_status_flags(pic32s->tx_irq, IRQ_NOAUTOEN); 820 ret = devm_request_irq(&pdev->dev, pic32s->tx_irq, 821 pic32_spi_tx_irq, IRQF_NO_THREAD, 822 dev_name(&pdev->dev), pic32s); 823 if (ret < 0) { 824 dev_err(&pdev->dev, "request tx-irq %d\n", pic32s->tx_irq); 825 goto err_bailout; 826 } 827 828 /* register master */ 829 ret = devm_spi_register_master(&pdev->dev, master); 830 if (ret) { 831 dev_err(&master->dev, "failed registering spi master\n"); 832 goto err_bailout; 833 } 834 835 platform_set_drvdata(pdev, pic32s); 836 837 return 0; 838 839 err_bailout: 840 pic32_spi_dma_unprep(pic32s); 841 clk_disable_unprepare(pic32s->clk); 842 err_master: 843 spi_master_put(master); 844 return ret; 845 } 846 847 static int pic32_spi_remove(struct platform_device *pdev) 848 { 849 struct pic32_spi *pic32s; 850 851 pic32s = platform_get_drvdata(pdev); 852 pic32_spi_disable(pic32s); 853 clk_disable_unprepare(pic32s->clk); 854 pic32_spi_dma_unprep(pic32s); 855 856 return 0; 857 } 858 859 static const struct of_device_id pic32_spi_of_match[] = { 860 {.compatible = "microchip,pic32mzda-spi",}, 861 {}, 862 }; 863 MODULE_DEVICE_TABLE(of, pic32_spi_of_match); 864 865 static struct platform_driver pic32_spi_driver = { 866 .driver = { 867 .name = "spi-pic32", 868 .of_match_table = of_match_ptr(pic32_spi_of_match), 869 }, 870 .probe = pic32_spi_probe, 871 .remove = pic32_spi_remove, 872 }; 873 874 module_platform_driver(pic32_spi_driver); 875 876 MODULE_AUTHOR("Purna Chandra Mandal <purna.mandal@microchip.com>"); 877 MODULE_DESCRIPTION("Microchip SPI driver for PIC32 SPI controller."); 878 MODULE_LICENSE("GPL v2"); 879