drivers/spi/spi-pic32-sqi.c

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This source file includes following definitions.
pic32_setbits
pic32_clrbits
pic32_sqi_set_clk_rate
pic32_sqi_enable_int
pic32_sqi_disable_int
pic32_sqi_isr
ring_desc_get
ring_desc_put
pic32_sqi_one_transfer
pic32_sqi_prepare_hardware
pic32_sqi_can_dma
pic32_sqi_one_message
pic32_sqi_unprepare_hardware
ring_desc_ring_alloc
ring_desc_ring_free
pic32_sqi_hw_init
pic32_sqi_probe
pic32_sqi_remove
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * PIC32 Quad 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/dma-mapping.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/io.h>
  13 #include <linux/iopoll.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/slab.h>
  18 #include <linux/spi/spi.h>
  19 
  20 /* SQI registers */
  21 #define PESQI_XIP_CONF1_REG     0x00
  22 #define PESQI_XIP_CONF2_REG     0x04
  23 #define PESQI_CONF_REG          0x08
  24 #define PESQI_CTRL_REG          0x0C
  25 #define PESQI_CLK_CTRL_REG      0x10
  26 #define PESQI_CMD_THRES_REG     0x14
  27 #define PESQI_INT_THRES_REG     0x18
  28 #define PESQI_INT_ENABLE_REG    0x1C
  29 #define PESQI_INT_STAT_REG      0x20
  30 #define PESQI_TX_DATA_REG       0x24
  31 #define PESQI_RX_DATA_REG       0x28
  32 #define PESQI_STAT1_REG         0x2C
  33 #define PESQI_STAT2_REG         0x30
  34 #define PESQI_BD_CTRL_REG       0x34
  35 #define PESQI_BD_CUR_ADDR_REG   0x38
  36 #define PESQI_BD_BASE_ADDR_REG  0x40
  37 #define PESQI_BD_STAT_REG       0x44
  38 #define PESQI_BD_POLL_CTRL_REG  0x48
  39 #define PESQI_BD_TX_DMA_STAT_REG        0x4C
  40 #define PESQI_BD_RX_DMA_STAT_REG        0x50
  41 #define PESQI_THRES_REG         0x54
  42 #define PESQI_INT_SIGEN_REG     0x58
  43 
  44 /* PESQI_CONF_REG fields */
  45 #define PESQI_MODE              0x7
  46 #define  PESQI_MODE_BOOT        0
  47 #define  PESQI_MODE_PIO         1
  48 #define  PESQI_MODE_DMA         2
  49 #define  PESQI_MODE_XIP         3
  50 #define PESQI_MODE_SHIFT        0
  51 #define PESQI_CPHA              BIT(3)
  52 #define PESQI_CPOL              BIT(4)
  53 #define PESQI_LSBF              BIT(5)
  54 #define PESQI_RXLATCH           BIT(7)
  55 #define PESQI_SERMODE           BIT(8)
  56 #define PESQI_WP_EN             BIT(9)
  57 #define PESQI_HOLD_EN           BIT(10)
  58 #define PESQI_BURST_EN          BIT(12)
  59 #define PESQI_CS_CTRL_HW        BIT(15)
  60 #define PESQI_SOFT_RESET        BIT(16)
  61 #define PESQI_LANES_SHIFT       20
  62 #define  PESQI_SINGLE_LANE      0
  63 #define  PESQI_DUAL_LANE        1
  64 #define  PESQI_QUAD_LANE        2
  65 #define PESQI_CSEN_SHIFT        24
  66 #define PESQI_EN                BIT(23)
  67 
  68 /* PESQI_CLK_CTRL_REG fields */
  69 #define PESQI_CLK_EN            BIT(0)
  70 #define PESQI_CLK_STABLE        BIT(1)
  71 #define PESQI_CLKDIV_SHIFT      8
  72 #define PESQI_CLKDIV            0xff
  73 
  74 /* PESQI_INT_THR/CMD_THR_REG */
  75 #define PESQI_TXTHR_MASK        0x1f
  76 #define PESQI_TXTHR_SHIFT       8
  77 #define PESQI_RXTHR_MASK        0x1f
  78 #define PESQI_RXTHR_SHIFT       0
  79 
  80 /* PESQI_INT_EN/INT_STAT/INT_SIG_EN_REG */
  81 #define PESQI_TXEMPTY           BIT(0)
  82 #define PESQI_TXFULL            BIT(1)
  83 #define PESQI_TXTHR             BIT(2)
  84 #define PESQI_RXEMPTY           BIT(3)
  85 #define PESQI_RXFULL            BIT(4)
  86 #define PESQI_RXTHR             BIT(5)
  87 #define PESQI_BDDONE            BIT(9)  /* BD processing complete */
  88 #define PESQI_PKTCOMP           BIT(10) /* packet processing complete */
  89 #define PESQI_DMAERR            BIT(11) /* error */
  90 
  91 /* PESQI_BD_CTRL_REG */
  92 #define PESQI_DMA_EN            BIT(0) /* enable DMA engine */
  93 #define PESQI_POLL_EN           BIT(1) /* enable polling */
  94 #define PESQI_BDP_START         BIT(2) /* start BD processor */
  95 
  96 /* PESQI controller buffer descriptor */
  97 struct buf_desc {
  98         u32 bd_ctrl;    /* control */
  99         u32 bd_status;  /* reserved */
 100         u32 bd_addr;    /* DMA buffer addr */
 101         u32 bd_nextp;   /* next item in chain */
 102 };
 103 
 104 /* bd_ctrl */
 105 #define BD_BUFLEN               0x1ff
 106 #define BD_CBD_INT_EN           BIT(16) /* Current BD is processed */
 107 #define BD_PKT_INT_EN           BIT(17) /* All BDs of PKT processed */
 108 #define BD_LIFM                 BIT(18) /* last data of pkt */
 109 #define BD_LAST                 BIT(19) /* end of list */
 110 #define BD_DATA_RECV            BIT(20) /* receive data */
 111 #define BD_DDR                  BIT(21) /* DDR mode */
 112 #define BD_DUAL                 BIT(22) /* Dual SPI */
 113 #define BD_QUAD                 BIT(23) /* Quad SPI */
 114 #define BD_LSBF                 BIT(25) /* LSB First */
 115 #define BD_STAT_CHECK           BIT(27) /* Status poll */
 116 #define BD_DEVSEL_SHIFT         28      /* CS */
 117 #define BD_CS_DEASSERT          BIT(30) /* de-assert CS after current BD */
 118 #define BD_EN                   BIT(31) /* BD owned by H/W */
 119 
 120 /**
 121  * struct ring_desc - Representation of SQI ring descriptor
 122  * @list:       list element to add to free or used list.
 123  * @bd:         PESQI controller buffer descriptor
 124  * @bd_dma:     DMA address of PESQI controller buffer descriptor
 125  * @xfer_len:   transfer length
 126  */
 127 struct ring_desc {
 128         struct list_head list;
 129         struct buf_desc *bd;
 130         dma_addr_t bd_dma;
 131         u32 xfer_len;
 132 };
 133 
 134 /* Global constants */
 135 #define PESQI_BD_BUF_LEN_MAX    256
 136 #define PESQI_BD_COUNT          256 /* max 64KB data per spi message */
 137 
 138 struct pic32_sqi {
 139         void __iomem            *regs;
 140         struct clk              *sys_clk;
 141         struct clk              *base_clk; /* drives spi clock */
 142         struct spi_master       *master;
 143         int                     irq;
 144         struct completion       xfer_done;
 145         struct ring_desc        *ring;
 146         void                    *bd;
 147         dma_addr_t              bd_dma;
 148         struct list_head        bd_list_free; /* free */
 149         struct list_head        bd_list_used; /* allocated */
 150         struct spi_device       *cur_spi;
 151         u32                     cur_speed;
 152         u8                      cur_mode;
 153 };
 154 
 155 static inline void pic32_setbits(void __iomem *reg, u32 set)
 156 {
 157         writel(readl(reg) | set, reg);
 158 }
 159 
 160 static inline void pic32_clrbits(void __iomem *reg, u32 clr)
 161 {
 162         writel(readl(reg) & ~clr, reg);
 163 }
 164 
 165 static int pic32_sqi_set_clk_rate(struct pic32_sqi *sqi, u32 sck)
 166 {
 167         u32 val, div;
 168 
 169         /* div = base_clk / (2 * spi_clk) */
 170         div = clk_get_rate(sqi->base_clk) / (2 * sck);
 171         div &= PESQI_CLKDIV;
 172 
 173         val = readl(sqi->regs + PESQI_CLK_CTRL_REG);
 174         /* apply new divider */
 175         val &= ~(PESQI_CLK_STABLE | (PESQI_CLKDIV << PESQI_CLKDIV_SHIFT));
 176         val |= div << PESQI_CLKDIV_SHIFT;
 177         writel(val, sqi->regs + PESQI_CLK_CTRL_REG);
 178 
 179         /* wait for stability */
 180         return readl_poll_timeout(sqi->regs + PESQI_CLK_CTRL_REG, val,
 181                                   val & PESQI_CLK_STABLE, 1, 5000);
 182 }
 183 
 184 static inline void pic32_sqi_enable_int(struct pic32_sqi *sqi)
 185 {
 186         u32 mask = PESQI_DMAERR | PESQI_BDDONE | PESQI_PKTCOMP;
 187 
 188         writel(mask, sqi->regs + PESQI_INT_ENABLE_REG);
 189         /* INT_SIGEN works as interrupt-gate to INTR line */
 190         writel(mask, sqi->regs + PESQI_INT_SIGEN_REG);
 191 }
 192 
 193 static inline void pic32_sqi_disable_int(struct pic32_sqi *sqi)
 194 {
 195         writel(0, sqi->regs + PESQI_INT_ENABLE_REG);
 196         writel(0, sqi->regs + PESQI_INT_SIGEN_REG);
 197 }
 198 
 199 static irqreturn_t pic32_sqi_isr(int irq, void *dev_id)
 200 {
 201         struct pic32_sqi *sqi = dev_id;
 202         u32 enable, status;
 203 
 204         enable = readl(sqi->regs + PESQI_INT_ENABLE_REG);
 205         status = readl(sqi->regs + PESQI_INT_STAT_REG);
 206 
 207         /* check spurious interrupt */
 208         if (!status)
 209                 return IRQ_NONE;
 210 
 211         if (status & PESQI_DMAERR) {
 212                 enable = 0;
 213                 goto irq_done;
 214         }
 215 
 216         if (status & PESQI_TXTHR)
 217                 enable &= ~(PESQI_TXTHR | PESQI_TXFULL | PESQI_TXEMPTY);
 218 
 219         if (status & PESQI_RXTHR)
 220                 enable &= ~(PESQI_RXTHR | PESQI_RXFULL | PESQI_RXEMPTY);
 221 
 222         if (status & PESQI_BDDONE)
 223                 enable &= ~PESQI_BDDONE;
 224 
 225         /* packet processing completed */
 226         if (status & PESQI_PKTCOMP) {
 227                 /* mask all interrupts */
 228                 enable = 0;
 229                 /* complete trasaction */
 230                 complete(&sqi->xfer_done);
 231         }
 232 
 233 irq_done:
 234         /* interrupts are sticky, so mask when handled */
 235         writel(enable, sqi->regs + PESQI_INT_ENABLE_REG);
 236 
 237         return IRQ_HANDLED;
 238 }
 239 
 240 static struct ring_desc *ring_desc_get(struct pic32_sqi *sqi)
 241 {
 242         struct ring_desc *rdesc;
 243 
 244         if (list_empty(&sqi->bd_list_free))
 245                 return NULL;
 246 
 247         rdesc = list_first_entry(&sqi->bd_list_free, struct ring_desc, list);
 248         list_move_tail(&rdesc->list, &sqi->bd_list_used);
 249         return rdesc;
 250 }
 251 
 252 static void ring_desc_put(struct pic32_sqi *sqi, struct ring_desc *rdesc)
 253 {
 254         list_move(&rdesc->list, &sqi->bd_list_free);
 255 }
 256 
 257 static int pic32_sqi_one_transfer(struct pic32_sqi *sqi,
 258                                   struct spi_message *mesg,
 259                                   struct spi_transfer *xfer)
 260 {
 261         struct spi_device *spi = mesg->spi;
 262         struct scatterlist *sg, *sgl;
 263         struct ring_desc *rdesc;
 264         struct buf_desc *bd;
 265         int nents, i;
 266         u32 bd_ctrl;
 267         u32 nbits;
 268 
 269         /* Device selection */
 270         bd_ctrl = spi->chip_select << BD_DEVSEL_SHIFT;
 271 
 272         /* half-duplex: select transfer buffer, direction and lane */
 273         if (xfer->rx_buf) {
 274                 bd_ctrl |= BD_DATA_RECV;
 275                 nbits = xfer->rx_nbits;
 276                 sgl = xfer->rx_sg.sgl;
 277                 nents = xfer->rx_sg.nents;
 278         } else {
 279                 nbits = xfer->tx_nbits;
 280                 sgl = xfer->tx_sg.sgl;
 281                 nents = xfer->tx_sg.nents;
 282         }
 283 
 284         if (nbits & SPI_NBITS_QUAD)
 285                 bd_ctrl |= BD_QUAD;
 286         else if (nbits & SPI_NBITS_DUAL)
 287                 bd_ctrl |= BD_DUAL;
 288 
 289         /* LSB first */
 290         if (spi->mode & SPI_LSB_FIRST)
 291                 bd_ctrl |= BD_LSBF;
 292 
 293         /* ownership to hardware */
 294         bd_ctrl |= BD_EN;
 295 
 296         for_each_sg(sgl, sg, nents, i) {
 297                 /* get ring descriptor */
 298                 rdesc = ring_desc_get(sqi);
 299                 if (!rdesc)
 300                         break;
 301 
 302                 bd = rdesc->bd;
 303 
 304                 /* BD CTRL: length */
 305                 rdesc->xfer_len = sg_dma_len(sg);
 306                 bd->bd_ctrl = bd_ctrl;
 307                 bd->bd_ctrl |= rdesc->xfer_len;
 308 
 309                 /* BD STAT */
 310                 bd->bd_status = 0;
 311 
 312                 /* BD BUFFER ADDRESS */
 313                 bd->bd_addr = sg->dma_address;
 314         }
 315 
 316         return 0;
 317 }
 318 
 319 static int pic32_sqi_prepare_hardware(struct spi_master *master)
 320 {
 321         struct pic32_sqi *sqi = spi_master_get_devdata(master);
 322 
 323         /* enable spi interface */
 324         pic32_setbits(sqi->regs + PESQI_CONF_REG, PESQI_EN);
 325         /* enable spi clk */
 326         pic32_setbits(sqi->regs + PESQI_CLK_CTRL_REG, PESQI_CLK_EN);
 327 
 328         return 0;
 329 }
 330 
 331 static bool pic32_sqi_can_dma(struct spi_master *master,
 332                               struct spi_device *spi,
 333                               struct spi_transfer *x)
 334 {
 335         /* Do DMA irrespective of transfer size */
 336         return true;
 337 }
 338 
 339 static int pic32_sqi_one_message(struct spi_master *master,
 340                                  struct spi_message *msg)
 341 {
 342         struct spi_device *spi = msg->spi;
 343         struct ring_desc *rdesc, *next;
 344         struct spi_transfer *xfer;
 345         struct pic32_sqi *sqi;
 346         int ret = 0, mode;
 347         unsigned long timeout;
 348         u32 val;
 349 
 350         sqi = spi_master_get_devdata(master);
 351 
 352         reinit_completion(&sqi->xfer_done);
 353         msg->actual_length = 0;
 354 
 355         /* We can't handle spi_transfer specific "speed_hz", "bits_per_word"
 356          * and "delay_usecs". But spi_device specific speed and mode change
 357          * can be handled at best during spi chip-select switch.
 358          */
 359         if (sqi->cur_spi != spi) {
 360                 /* set spi speed */
 361                 if (sqi->cur_speed != spi->max_speed_hz) {
 362                         sqi->cur_speed = spi->max_speed_hz;
 363                         ret = pic32_sqi_set_clk_rate(sqi, spi->max_speed_hz);
 364                         if (ret)
 365                                 dev_warn(&spi->dev, "set_clk, %d\n", ret);
 366                 }
 367 
 368                 /* set spi mode */
 369                 mode = spi->mode & (SPI_MODE_3 | SPI_LSB_FIRST);
 370                 if (sqi->cur_mode != mode) {
 371                         val = readl(sqi->regs + PESQI_CONF_REG);
 372                         val &= ~(PESQI_CPOL | PESQI_CPHA | PESQI_LSBF);
 373                         if (mode & SPI_CPOL)
 374                                 val |= PESQI_CPOL;
 375                         if (mode & SPI_LSB_FIRST)
 376                                 val |= PESQI_LSBF;
 377                         val |= PESQI_CPHA;
 378                         writel(val, sqi->regs + PESQI_CONF_REG);
 379 
 380                         sqi->cur_mode = mode;
 381                 }
 382                 sqi->cur_spi = spi;
 383         }
 384 
 385         /* prepare hardware desc-list(BD) for transfer(s) */
 386         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 387                 ret = pic32_sqi_one_transfer(sqi, msg, xfer);
 388                 if (ret) {
 389                         dev_err(&spi->dev, "xfer %p err\n", xfer);
 390                         goto xfer_out;
 391                 }
 392         }
 393 
 394         /* BDs are prepared and chained. Now mark LAST_BD, CS_DEASSERT at last
 395          * element of the list.
 396          */
 397         rdesc = list_last_entry(&sqi->bd_list_used, struct ring_desc, list);
 398         rdesc->bd->bd_ctrl |= BD_LAST | BD_CS_DEASSERT |
 399                               BD_LIFM | BD_PKT_INT_EN;
 400 
 401         /* set base address BD list for DMA engine */
 402         rdesc = list_first_entry(&sqi->bd_list_used, struct ring_desc, list);
 403         writel(rdesc->bd_dma, sqi->regs + PESQI_BD_BASE_ADDR_REG);
 404 
 405         /* enable interrupt */
 406         pic32_sqi_enable_int(sqi);
 407 
 408         /* enable DMA engine */
 409         val = PESQI_DMA_EN | PESQI_POLL_EN | PESQI_BDP_START;
 410         writel(val, sqi->regs + PESQI_BD_CTRL_REG);
 411 
 412         /* wait for xfer completion */
 413         timeout = wait_for_completion_timeout(&sqi->xfer_done, 5 * HZ);
 414         if (timeout == 0) {
 415                 dev_err(&sqi->master->dev, "wait timedout/interrupted\n");
 416                 ret = -ETIMEDOUT;
 417                 msg->status = ret;
 418         } else {
 419                 /* success */
 420                 msg->status = 0;
 421                 ret = 0;
 422         }
 423 
 424         /* disable DMA */
 425         writel(0, sqi->regs + PESQI_BD_CTRL_REG);
 426 
 427         pic32_sqi_disable_int(sqi);
 428 
 429 xfer_out:
 430         list_for_each_entry_safe_reverse(rdesc, next,
 431                                          &sqi->bd_list_used, list) {
 432                 /* Update total byte transferred */
 433                 msg->actual_length += rdesc->xfer_len;
 434                 /* release ring descr */
 435                 ring_desc_put(sqi, rdesc);
 436         }
 437         spi_finalize_current_message(spi->master);
 438 
 439         return ret;
 440 }
 441 
 442 static int pic32_sqi_unprepare_hardware(struct spi_master *master)
 443 {
 444         struct pic32_sqi *sqi = spi_master_get_devdata(master);
 445 
 446         /* disable clk */
 447         pic32_clrbits(sqi->regs + PESQI_CLK_CTRL_REG, PESQI_CLK_EN);
 448         /* disable spi */
 449         pic32_clrbits(sqi->regs + PESQI_CONF_REG, PESQI_EN);
 450 
 451         return 0;
 452 }
 453 
 454 static int ring_desc_ring_alloc(struct pic32_sqi *sqi)
 455 {
 456         struct ring_desc *rdesc;
 457         struct buf_desc *bd;
 458         int i;
 459 
 460         /* allocate coherent DMAable memory for hardware buffer descriptors. */
 461         sqi->bd = dma_alloc_coherent(&sqi->master->dev,
 462                                      sizeof(*bd) * PESQI_BD_COUNT,
 463                                      &sqi->bd_dma, GFP_KERNEL);
 464         if (!sqi->bd) {
 465                 dev_err(&sqi->master->dev, "failed allocating dma buffer\n");
 466                 return -ENOMEM;
 467         }
 468 
 469         /* allocate software ring descriptors */
 470         sqi->ring = kcalloc(PESQI_BD_COUNT, sizeof(*rdesc), GFP_KERNEL);
 471         if (!sqi->ring) {
 472                 dma_free_coherent(&sqi->master->dev,
 473                                   sizeof(*bd) * PESQI_BD_COUNT,
 474                                   sqi->bd, sqi->bd_dma);
 475                 return -ENOMEM;
 476         }
 477 
 478         bd = (struct buf_desc *)sqi->bd;
 479 
 480         INIT_LIST_HEAD(&sqi->bd_list_free);
 481         INIT_LIST_HEAD(&sqi->bd_list_used);
 482 
 483         /* initialize ring-desc */
 484         for (i = 0, rdesc = sqi->ring; i < PESQI_BD_COUNT; i++, rdesc++) {
 485                 INIT_LIST_HEAD(&rdesc->list);
 486                 rdesc->bd = &bd[i];
 487                 rdesc->bd_dma = sqi->bd_dma + (void *)&bd[i] - (void *)bd;
 488                 list_add_tail(&rdesc->list, &sqi->bd_list_free);
 489         }
 490 
 491         /* Prepare BD: chain to next BD(s) */
 492         for (i = 0, rdesc = sqi->ring; i < PESQI_BD_COUNT - 1; i++)
 493                 bd[i].bd_nextp = rdesc[i + 1].bd_dma;
 494         bd[PESQI_BD_COUNT - 1].bd_nextp = 0;
 495 
 496         return 0;
 497 }
 498 
 499 static void ring_desc_ring_free(struct pic32_sqi *sqi)
 500 {
 501         dma_free_coherent(&sqi->master->dev,
 502                           sizeof(struct buf_desc) * PESQI_BD_COUNT,
 503                           sqi->bd, sqi->bd_dma);
 504         kfree(sqi->ring);
 505 }
 506 
 507 static void pic32_sqi_hw_init(struct pic32_sqi *sqi)
 508 {
 509         unsigned long flags;
 510         u32 val;
 511 
 512         /* Soft-reset of PESQI controller triggers interrupt.
 513          * We are not yet ready to handle them so disable CPU
 514          * interrupt for the time being.
 515          */
 516         local_irq_save(flags);
 517 
 518         /* assert soft-reset */
 519         writel(PESQI_SOFT_RESET, sqi->regs + PESQI_CONF_REG);
 520 
 521         /* wait until clear */
 522         readl_poll_timeout_atomic(sqi->regs + PESQI_CONF_REG, val,
 523                                   !(val & PESQI_SOFT_RESET), 1, 5000);
 524 
 525         /* disable all interrupts */
 526         pic32_sqi_disable_int(sqi);
 527 
 528         /* Now it is safe to enable back CPU interrupt */
 529         local_irq_restore(flags);
 530 
 531         /* tx and rx fifo interrupt threshold */
 532         val = readl(sqi->regs + PESQI_CMD_THRES_REG);
 533         val &= ~(PESQI_TXTHR_MASK << PESQI_TXTHR_SHIFT);
 534         val &= ~(PESQI_RXTHR_MASK << PESQI_RXTHR_SHIFT);
 535         val |= (1U << PESQI_TXTHR_SHIFT) | (1U << PESQI_RXTHR_SHIFT);
 536         writel(val, sqi->regs + PESQI_CMD_THRES_REG);
 537 
 538         val = readl(sqi->regs + PESQI_INT_THRES_REG);
 539         val &= ~(PESQI_TXTHR_MASK << PESQI_TXTHR_SHIFT);
 540         val &= ~(PESQI_RXTHR_MASK << PESQI_RXTHR_SHIFT);
 541         val |= (1U << PESQI_TXTHR_SHIFT) | (1U << PESQI_RXTHR_SHIFT);
 542         writel(val, sqi->regs + PESQI_INT_THRES_REG);
 543 
 544         /* default configuration */
 545         val = readl(sqi->regs + PESQI_CONF_REG);
 546 
 547         /* set mode: DMA */
 548         val &= ~PESQI_MODE;
 549         val |= PESQI_MODE_DMA << PESQI_MODE_SHIFT;
 550         writel(val, sqi->regs + PESQI_CONF_REG);
 551 
 552         /* DATAEN - SQIID0-ID3 */
 553         val |= PESQI_QUAD_LANE << PESQI_LANES_SHIFT;
 554 
 555         /* burst/INCR4 enable */
 556         val |= PESQI_BURST_EN;
 557 
 558         /* CSEN - all CS */
 559         val |= 3U << PESQI_CSEN_SHIFT;
 560         writel(val, sqi->regs + PESQI_CONF_REG);
 561 
 562         /* write poll count */
 563         writel(0, sqi->regs + PESQI_BD_POLL_CTRL_REG);
 564 
 565         sqi->cur_speed = 0;
 566         sqi->cur_mode = -1;
 567 }
 568 
 569 static int pic32_sqi_probe(struct platform_device *pdev)
 570 {
 571         struct spi_master *master;
 572         struct pic32_sqi *sqi;
 573         int ret;
 574 
 575         master = spi_alloc_master(&pdev->dev, sizeof(*sqi));
 576         if (!master)
 577                 return -ENOMEM;
 578 
 579         sqi = spi_master_get_devdata(master);
 580         sqi->master = master;
 581 
 582         sqi->regs = devm_platform_ioremap_resource(pdev, 0);
 583         if (IS_ERR(sqi->regs)) {
 584                 ret = PTR_ERR(sqi->regs);
 585                 goto err_free_master;
 586         }
 587 
 588         /* irq */
 589         sqi->irq = platform_get_irq(pdev, 0);
 590         if (sqi->irq < 0) {
 591                 ret = sqi->irq;
 592                 goto err_free_master;
 593         }
 594 
 595         /* clocks */
 596         sqi->sys_clk = devm_clk_get(&pdev->dev, "reg_ck");
 597         if (IS_ERR(sqi->sys_clk)) {
 598                 ret = PTR_ERR(sqi->sys_clk);
 599                 dev_err(&pdev->dev, "no sys_clk ?\n");
 600                 goto err_free_master;
 601         }
 602 
 603         sqi->base_clk = devm_clk_get(&pdev->dev, "spi_ck");
 604         if (IS_ERR(sqi->base_clk)) {
 605                 ret = PTR_ERR(sqi->base_clk);
 606                 dev_err(&pdev->dev, "no base clk ?\n");
 607                 goto err_free_master;
 608         }
 609 
 610         ret = clk_prepare_enable(sqi->sys_clk);
 611         if (ret) {
 612                 dev_err(&pdev->dev, "sys clk enable failed\n");
 613                 goto err_free_master;
 614         }
 615 
 616         ret = clk_prepare_enable(sqi->base_clk);
 617         if (ret) {
 618                 dev_err(&pdev->dev, "base clk enable failed\n");
 619                 clk_disable_unprepare(sqi->sys_clk);
 620                 goto err_free_master;
 621         }
 622 
 623         init_completion(&sqi->xfer_done);
 624 
 625         /* initialize hardware */
 626         pic32_sqi_hw_init(sqi);
 627 
 628         /* allocate buffers & descriptors */
 629         ret = ring_desc_ring_alloc(sqi);
 630         if (ret) {
 631                 dev_err(&pdev->dev, "ring alloc failed\n");
 632                 goto err_disable_clk;
 633         }
 634 
 635         /* install irq handlers */
 636         ret = request_irq(sqi->irq, pic32_sqi_isr, 0,
 637                           dev_name(&pdev->dev), sqi);
 638         if (ret < 0) {
 639                 dev_err(&pdev->dev, "request_irq(%d), failed\n", sqi->irq);
 640                 goto err_free_ring;
 641         }
 642 
 643         /* register master */
 644         master->num_chipselect  = 2;
 645         master->max_speed_hz    = clk_get_rate(sqi->base_clk);
 646         master->dma_alignment   = 32;
 647         master->max_dma_len     = PESQI_BD_BUF_LEN_MAX;
 648         master->dev.of_node     = pdev->dev.of_node;
 649         master->mode_bits       = SPI_MODE_3 | SPI_MODE_0 | SPI_TX_DUAL |
 650                                   SPI_RX_DUAL | SPI_TX_QUAD | SPI_RX_QUAD;
 651         master->flags           = SPI_MASTER_HALF_DUPLEX;
 652         master->can_dma         = pic32_sqi_can_dma;
 653         master->bits_per_word_mask      = SPI_BPW_RANGE_MASK(8, 32);
 654         master->transfer_one_message    = pic32_sqi_one_message;
 655         master->prepare_transfer_hardware       = pic32_sqi_prepare_hardware;
 656         master->unprepare_transfer_hardware     = pic32_sqi_unprepare_hardware;
 657 
 658         ret = devm_spi_register_master(&pdev->dev, master);
 659         if (ret) {
 660                 dev_err(&master->dev, "failed registering spi master\n");
 661                 free_irq(sqi->irq, sqi);
 662                 goto err_free_ring;
 663         }
 664 
 665         platform_set_drvdata(pdev, sqi);
 666 
 667         return 0;
 668 
 669 err_free_ring:
 670         ring_desc_ring_free(sqi);
 671 
 672 err_disable_clk:
 673         clk_disable_unprepare(sqi->base_clk);
 674         clk_disable_unprepare(sqi->sys_clk);
 675 
 676 err_free_master:
 677         spi_master_put(master);
 678         return ret;
 679 }
 680 
 681 static int pic32_sqi_remove(struct platform_device *pdev)
 682 {
 683         struct pic32_sqi *sqi = platform_get_drvdata(pdev);
 684 
 685         /* release resources */
 686         free_irq(sqi->irq, sqi);
 687         ring_desc_ring_free(sqi);
 688 
 689         /* disable clk */
 690         clk_disable_unprepare(sqi->base_clk);
 691         clk_disable_unprepare(sqi->sys_clk);
 692 
 693         return 0;
 694 }
 695 
 696 static const struct of_device_id pic32_sqi_of_ids[] = {
 697         {.compatible = "microchip,pic32mzda-sqi",},
 698         {},
 699 };
 700 MODULE_DEVICE_TABLE(of, pic32_sqi_of_ids);
 701 
 702 static struct platform_driver pic32_sqi_driver = {
 703         .driver = {
 704                 .name = "sqi-pic32",
 705                 .of_match_table = of_match_ptr(pic32_sqi_of_ids),
 706         },
 707         .probe = pic32_sqi_probe,
 708         .remove = pic32_sqi_remove,
 709 };
 710 
 711 module_platform_driver(pic32_sqi_driver);
 712 
 713 MODULE_AUTHOR("Purna Chandra Mandal <purna.mandal@microchip.com>");
 714 MODULE_DESCRIPTION("Microchip SPI driver for PIC32 SQI controller.");
 715 MODULE_LICENSE("GPL v2");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/spi/spi-pic32-sqi.c

DEFINITIONS
