drivers/spi/spi-mpc52xx-psc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * MPC52xx PSC in SPI mode driver.
   4  *
   5  * Maintainer: Dragos Carp
   6  *
   7  * Copyright (C) 2006 TOPTICA Photonics AG.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/errno.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_platform.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/completion.h>
  18 #include <linux/io.h>
  19 #include <linux/delay.h>
  20 #include <linux/spi/spi.h>
  21 #include <linux/fsl_devices.h>
  22 #include <linux/slab.h>
  23
  24 #include <asm/mpc52xx.h>
  25 #include <asm/mpc52xx_psc.h>
  26
  27 #define MCLK 20000000 /* PSC port MClk in hz */
  28
  29 struct mpc52xx_psc_spi {
  30         /* fsl_spi_platform data */
  31         void (*cs_control)(struct spi_device *spi, bool on);
  32         u32 sysclk;
  33
  34         /* driver internal data */
  35         struct mpc52xx_psc __iomem *psc;
  36         struct mpc52xx_psc_fifo __iomem *fifo;
  37         unsigned int irq;
  38         u8 bits_per_word;
  39         u8 busy;
  40
  41         struct work_struct work;
  42
  43         struct list_head queue;
  44         spinlock_t lock;
  45
  46         struct completion done;
  47 };
  48
  49 /* controller state */
  50 struct mpc52xx_psc_spi_cs {
  51         int bits_per_word;
  52         int speed_hz;
  53 };
  54
  55 /* set clock freq, clock ramp, bits per work
  56  * if t is NULL then reset the values to the default values
  57  */
  58 static int mpc52xx_psc_spi_transfer_setup(struct spi_device *spi,
  59                 struct spi_transfer *t)
  60 {
  61         struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
  62
  63         cs->speed_hz = (t && t->speed_hz)
  64                         ? t->speed_hz : spi->max_speed_hz;
  65         cs->bits_per_word = (t && t->bits_per_word)
  66                         ? t->bits_per_word : spi->bits_per_word;
  67         cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
  68         return 0;
  69 }
  70
  71 static void mpc52xx_psc_spi_activate_cs(struct spi_device *spi)
  72 {
  73         struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
  74         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
  75         struct mpc52xx_psc __iomem *psc = mps->psc;
  76         u32 sicr;
  77         u16 ccr;
  78
  79         sicr = in_be32(&psc->sicr);
  80
  81         /* Set clock phase and polarity */
  82         if (spi->mode & SPI_CPHA)
  83                 sicr |= 0x00001000;
  84         else
  85                 sicr &= ~0x00001000;
  86         if (spi->mode & SPI_CPOL)
  87                 sicr |= 0x00002000;
  88         else
  89                 sicr &= ~0x00002000;
  90
  91         if (spi->mode & SPI_LSB_FIRST)
  92                 sicr |= 0x10000000;
  93         else
  94                 sicr &= ~0x10000000;
  95         out_be32(&psc->sicr, sicr);
  96
  97         /* Set clock frequency and bits per word
  98          * Because psc->ccr is defined as 16bit register instead of 32bit
  99          * just set the lower byte of BitClkDiv
 100          */
 101         ccr = in_be16((u16 __iomem *)&psc->ccr);
 102         ccr &= 0xFF00;
 103         if (cs->speed_hz)
 104                 ccr |= (MCLK / cs->speed_hz - 1) & 0xFF;
 105         else /* by default SPI Clk 1MHz */
 106                 ccr |= (MCLK / 1000000 - 1) & 0xFF;
 107         out_be16((u16 __iomem *)&psc->ccr, ccr);
 108         mps->bits_per_word = cs->bits_per_word;
 109
 110         if (mps->cs_control)
 111                 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0);
 112 }
 113
 114 static void mpc52xx_psc_spi_deactivate_cs(struct spi_device *spi)
 115 {
 116         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
 117
 118         if (mps->cs_control)
 119                 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
 120 }
 121
 122 #define MPC52xx_PSC_BUFSIZE (MPC52xx_PSC_RFNUM_MASK + 1)
 123 /* wake up when 80% fifo full */
 124 #define MPC52xx_PSC_RFALARM (MPC52xx_PSC_BUFSIZE * 20 / 100)
 125
 126 static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi,
 127                                                 struct spi_transfer *t)
 128 {
 129         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
 130         struct mpc52xx_psc __iomem *psc = mps->psc;
 131         struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
 132         unsigned rb = 0;        /* number of bytes receieved */
 133         unsigned sb = 0;        /* number of bytes sent */
 134         unsigned char *rx_buf = (unsigned char *)t->rx_buf;
 135         unsigned char *tx_buf = (unsigned char *)t->tx_buf;
 136         unsigned rfalarm;
 137         unsigned send_at_once = MPC52xx_PSC_BUFSIZE;
 138         unsigned recv_at_once;
 139         int last_block = 0;
 140
 141         if (!t->tx_buf && !t->rx_buf && t->len)
 142                 return -EINVAL;
 143
 144         /* enable transmiter/receiver */
 145         out_8(&psc->command, MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
 146         while (rb < t->len) {
 147                 if (t->len - rb > MPC52xx_PSC_BUFSIZE) {
 148                         rfalarm = MPC52xx_PSC_RFALARM;
 149                         last_block = 0;
 150                 } else {
 151                         send_at_once = t->len - sb;
 152                         rfalarm = MPC52xx_PSC_BUFSIZE - (t->len - rb);
 153                         last_block = 1;
 154                 }
 155
 156                 dev_dbg(&spi->dev, "send %d bytes...\n", send_at_once);
 157                 for (; send_at_once; sb++, send_at_once--) {
 158                         /* set EOF flag before the last word is sent */
 159                         if (send_at_once == 1 && last_block)
 160                                 out_8(&psc->ircr2, 0x01);
 161
 162                         if (tx_buf)
 163                                 out_8(&psc->mpc52xx_psc_buffer_8, tx_buf[sb]);
 164                         else
 165                                 out_8(&psc->mpc52xx_psc_buffer_8, 0);
 166                 }
 167
 168
 169                 /* enable interrupts and wait for wake up
 170                  * if just one byte is expected the Rx FIFO genererates no
 171                  * FFULL interrupt, so activate the RxRDY interrupt
 172                  */
 173                 out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
 174                 if (t->len - rb == 1) {
 175                         out_8(&psc->mode, 0);
 176                 } else {
 177                         out_8(&psc->mode, MPC52xx_PSC_MODE_FFULL);
 178                         out_be16(&fifo->rfalarm, rfalarm);
 179                 }
 180                 out_be16(&psc->mpc52xx_psc_imr, MPC52xx_PSC_IMR_RXRDY);
 181                 wait_for_completion(&mps->done);
 182                 recv_at_once = in_be16(&fifo->rfnum);
 183                 dev_dbg(&spi->dev, "%d bytes received\n", recv_at_once);
 184
 185                 send_at_once = recv_at_once;
 186                 if (rx_buf) {
 187                         for (; recv_at_once; rb++, recv_at_once--)
 188                                 rx_buf[rb] = in_8(&psc->mpc52xx_psc_buffer_8);
 189                 } else {
 190                         for (; recv_at_once; rb++, recv_at_once--)
 191                                 in_8(&psc->mpc52xx_psc_buffer_8);
 192                 }
 193         }
 194         /* disable transmiter/receiver */
 195         out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
 196
 197         return 0;
 198 }
 199
 200 static void mpc52xx_psc_spi_work(struct work_struct *work)
 201 {
 202         struct mpc52xx_psc_spi *mps =
 203                 container_of(work, struct mpc52xx_psc_spi, work);
 204
 205         spin_lock_irq(&mps->lock);
 206         mps->busy = 1;
 207         while (!list_empty(&mps->queue)) {
 208                 struct spi_message *m;
 209                 struct spi_device *spi;
 210                 struct spi_transfer *t = NULL;
 211                 unsigned cs_change;
 212                 int status;
 213
 214                 m = container_of(mps->queue.next, struct spi_message, queue);
 215                 list_del_init(&m->queue);
 216                 spin_unlock_irq(&mps->lock);
 217
 218                 spi = m->spi;
 219                 cs_change = 1;
 220                 status = 0;
 221                 list_for_each_entry (t, &m->transfers, transfer_list) {
 222                         if (t->bits_per_word || t->speed_hz) {
 223                                 status = mpc52xx_psc_spi_transfer_setup(spi, t);
 224                                 if (status < 0)
 225                                         break;
 226                         }
 227
 228                         if (cs_change)
 229                                 mpc52xx_psc_spi_activate_cs(spi);
 230                         cs_change = t->cs_change;
 231
 232                         status = mpc52xx_psc_spi_transfer_rxtx(spi, t);
 233                         if (status)
 234                                 break;
 235                         m->actual_length += t->len;
 236
 237                         if (t->delay_usecs)
 238                                 udelay(t->delay_usecs);
 239
 240                         if (cs_change)
 241                                 mpc52xx_psc_spi_deactivate_cs(spi);
 242                 }
 243
 244                 m->status = status;
 245                 if (m->complete)
 246                         m->complete(m->context);
 247
 248                 if (status || !cs_change)
 249                         mpc52xx_psc_spi_deactivate_cs(spi);
 250
 251                 mpc52xx_psc_spi_transfer_setup(spi, NULL);
 252
 253                 spin_lock_irq(&mps->lock);
 254         }
 255         mps->busy = 0;
 256         spin_unlock_irq(&mps->lock);
 257 }
 258
 259 static int mpc52xx_psc_spi_setup(struct spi_device *spi)
 260 {
 261         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
 262         struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
 263         unsigned long flags;
 264
 265         if (spi->bits_per_word%8)
 266                 return -EINVAL;
 267
 268         if (!cs) {
 269                 cs = kzalloc(sizeof *cs, GFP_KERNEL);
 270                 if (!cs)
 271                         return -ENOMEM;
 272                 spi->controller_state = cs;
 273         }
 274
 275         cs->bits_per_word = spi->bits_per_word;
 276         cs->speed_hz = spi->max_speed_hz;
 277
 278         spin_lock_irqsave(&mps->lock, flags);
 279         if (!mps->busy)
 280                 mpc52xx_psc_spi_deactivate_cs(spi);
 281         spin_unlock_irqrestore(&mps->lock, flags);
 282
 283         return 0;
 284 }
 285
 286 static int mpc52xx_psc_spi_transfer(struct spi_device *spi,
 287                 struct spi_message *m)
 288 {
 289         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
 290         unsigned long flags;
 291
 292         m->actual_length = 0;
 293         m->status = -EINPROGRESS;
 294
 295         spin_lock_irqsave(&mps->lock, flags);
 296         list_add_tail(&m->queue, &mps->queue);
 297         schedule_work(&mps->work);
 298         spin_unlock_irqrestore(&mps->lock, flags);
 299
 300         return 0;
 301 }
 302
 303 static void mpc52xx_psc_spi_cleanup(struct spi_device *spi)
 304 {
 305         kfree(spi->controller_state);
 306 }
 307
 308 static int mpc52xx_psc_spi_port_config(int psc_id, struct mpc52xx_psc_spi *mps)
 309 {
 310         struct mpc52xx_psc __iomem *psc = mps->psc;
 311         struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
 312         u32 mclken_div;
 313         int ret;
 314
 315         /* default sysclk is 512MHz */
 316         mclken_div = (mps->sysclk ? mps->sysclk : 512000000) / MCLK;
 317         ret = mpc52xx_set_psc_clkdiv(psc_id, mclken_div);
 318         if (ret)
 319                 return ret;
 320
 321         /* Reset the PSC into a known state */
 322         out_8(&psc->command, MPC52xx_PSC_RST_RX);
 323         out_8(&psc->command, MPC52xx_PSC_RST_TX);
 324         out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
 325
 326         /* Disable interrupts, interrupts are based on alarm level */
 327         out_be16(&psc->mpc52xx_psc_imr, 0);
 328         out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
 329         out_8(&fifo->rfcntl, 0);
 330         out_8(&psc->mode, MPC52xx_PSC_MODE_FFULL);
 331
 332         /* Configure 8bit codec mode as a SPI master and use EOF flags */
 333         /* SICR_SIM_CODEC8|SICR_GENCLK|SICR_SPI|SICR_MSTR|SICR_USEEOF */
 334         out_be32(&psc->sicr, 0x0180C800);
 335         out_be16((u16 __iomem *)&psc->ccr, 0x070F); /* default SPI Clk 1MHz */
 336
 337         /* Set 2ms DTL delay */
 338         out_8(&psc->ctur, 0x00);
 339         out_8(&psc->ctlr, 0x84);
 340
 341         mps->bits_per_word = 8;
 342
 343         return 0;
 344 }
 345
 346 static irqreturn_t mpc52xx_psc_spi_isr(int irq, void *dev_id)
 347 {
 348         struct mpc52xx_psc_spi *mps = (struct mpc52xx_psc_spi *)dev_id;
 349         struct mpc52xx_psc __iomem *psc = mps->psc;
 350
 351         /* disable interrupt and wake up the work queue */
 352         if (in_be16(&psc->mpc52xx_psc_isr) & MPC52xx_PSC_IMR_RXRDY) {
 353                 out_be16(&psc->mpc52xx_psc_imr, 0);
 354                 complete(&mps->done);
 355                 return IRQ_HANDLED;
 356         }
 357         return IRQ_NONE;
 358 }
 359
 360 /* bus_num is used only for the case dev->platform_data == NULL */
 361 static int mpc52xx_psc_spi_do_probe(struct device *dev, u32 regaddr,
 362                                 u32 size, unsigned int irq, s16 bus_num)
 363 {
 364         struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
 365         struct mpc52xx_psc_spi *mps;
 366         struct spi_master *master;
 367         int ret;
 368
 369         master = spi_alloc_master(dev, sizeof *mps);
 370         if (master == NULL)
 371                 return -ENOMEM;
 372
 373         dev_set_drvdata(dev, master);
 374         mps = spi_master_get_devdata(master);
 375
 376         /* the spi->mode bits understood by this driver: */
 377         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
 378
 379         mps->irq = irq;
 380         if (pdata == NULL) {
 381                 dev_warn(dev,
 382                          "probe called without platform data, no cs_control function will be called\n");
 383                 mps->cs_control = NULL;
 384                 mps->sysclk = 0;
 385                 master->bus_num = bus_num;
 386                 master->num_chipselect = 255;
 387         } else {
 388                 mps->cs_control = pdata->cs_control;
 389                 mps->sysclk = pdata->sysclk;
 390                 master->bus_num = pdata->bus_num;
 391                 master->num_chipselect = pdata->max_chipselect;
 392         }
 393         master->setup = mpc52xx_psc_spi_setup;
 394         master->transfer = mpc52xx_psc_spi_transfer;
 395         master->cleanup = mpc52xx_psc_spi_cleanup;
 396         master->dev.of_node = dev->of_node;
 397
 398         mps->psc = ioremap(regaddr, size);
 399         if (!mps->psc) {
 400                 dev_err(dev, "could not ioremap I/O port range\n");
 401                 ret = -EFAULT;
 402                 goto free_master;
 403         }
 404         /* On the 5200, fifo regs are immediately ajacent to the psc regs */
 405         mps->fifo = ((void __iomem *)mps->psc) + sizeof(struct mpc52xx_psc);
 406
 407         ret = request_irq(mps->irq, mpc52xx_psc_spi_isr, 0, "mpc52xx-psc-spi",
 408                                 mps);
 409         if (ret)
 410                 goto free_master;
 411
 412         ret = mpc52xx_psc_spi_port_config(master->bus_num, mps);
 413         if (ret < 0) {
 414                 dev_err(dev, "can't configure PSC! Is it capable of SPI?\n");
 415                 goto free_irq;
 416         }
 417
 418         spin_lock_init(&mps->lock);
 419         init_completion(&mps->done);
 420         INIT_WORK(&mps->work, mpc52xx_psc_spi_work);
 421         INIT_LIST_HEAD(&mps->queue);
 422
 423         ret = spi_register_master(master);
 424         if (ret < 0)
 425                 goto free_irq;
 426
 427         return ret;
 428
 429 free_irq:
 430         free_irq(mps->irq, mps);
 431 free_master:
 432         if (mps->psc)
 433                 iounmap(mps->psc);
 434         spi_master_put(master);
 435
 436         return ret;
 437 }
 438
 439 static int mpc52xx_psc_spi_of_probe(struct platform_device *op)
 440 {
 441         const u32 *regaddr_p;
 442         u64 regaddr64, size64;
 443         s16 id = -1;
 444
 445         regaddr_p = of_get_address(op->dev.of_node, 0, &size64, NULL);
 446         if (!regaddr_p) {
 447                 dev_err(&op->dev, "Invalid PSC address\n");
 448                 return -EINVAL;
 449         }
 450         regaddr64 = of_translate_address(op->dev.of_node, regaddr_p);
 451
 452         /* get PSC id (1..6, used by port_config) */
 453         if (op->dev.platform_data == NULL) {
 454                 const u32 *psc_nump;
 455
 456                 psc_nump = of_get_property(op->dev.of_node, "cell-index", NULL);
 457                 if (!psc_nump || *psc_nump > 5) {
 458                         dev_err(&op->dev, "Invalid cell-index property\n");
 459                         return -EINVAL;
 460                 }
 461                 id = *psc_nump + 1;
 462         }
 463
 464         return mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
 465                                 irq_of_parse_and_map(op->dev.of_node, 0), id);
 466 }
 467
 468 static int mpc52xx_psc_spi_of_remove(struct platform_device *op)
 469 {
 470         struct spi_master *master = spi_master_get(platform_get_drvdata(op));
 471         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(master);
 472
 473         flush_work(&mps->work);
 474         spi_unregister_master(master);
 475         free_irq(mps->irq, mps);
 476         if (mps->psc)
 477                 iounmap(mps->psc);
 478         spi_master_put(master);
 479
 480         return 0;
 481 }
 482
 483 static const struct of_device_id mpc52xx_psc_spi_of_match[] = {
 484         { .compatible = "fsl,mpc5200-psc-spi", },
 485         { .compatible = "mpc5200-psc-spi", }, /* old */
 486         {}
 487 };
 488
 489 MODULE_DEVICE_TABLE(of, mpc52xx_psc_spi_of_match);
 490
 491 static struct platform_driver mpc52xx_psc_spi_of_driver = {
 492         .probe = mpc52xx_psc_spi_of_probe,
 493         .remove = mpc52xx_psc_spi_of_remove,
 494         .driver = {
 495                 .name = "mpc52xx-psc-spi",
 496                 .of_match_table = mpc52xx_psc_spi_of_match,
 497         },
 498 };
 499 module_platform_driver(mpc52xx_psc_spi_of_driver);
 500
 501 MODULE_AUTHOR("Dragos Carp");
 502 MODULE_DESCRIPTION("MPC52xx PSC SPI Driver");
 503 MODULE_LICENSE("GPL");