drivers/spi/spi-omap-100k.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * OMAP7xx SPI 100k controller driver
   4  * Author: Fabrice Crohas <fcrohas@gmail.com>
   5  * from original omap1_mcspi driver
   6  *
   7  * Copyright (C) 2005, 2006 Nokia Corporation
   8  * Author:      Samuel Ortiz <samuel.ortiz@nokia.com> and
   9  *              Juha Yrjola <juha.yrjola@nokia.com>
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/module.h>
  15 #include <linux/device.h>
  16 #include <linux/delay.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/pm_runtime.h>
  19 #include <linux/err.h>
  20 #include <linux/clk.h>
  21 #include <linux/io.h>
  22 #include <linux/slab.h>
  23
  24 #include <linux/spi/spi.h>
  25
  26 #define OMAP1_SPI100K_MAX_FREQ          48000000
  27
  28 #define ICR_SPITAS      (OMAP7XX_ICR_BASE + 0x12)
  29
  30 #define SPI_SETUP1      0x00
  31 #define SPI_SETUP2      0x02
  32 #define SPI_CTRL        0x04
  33 #define SPI_STATUS      0x06
  34 #define SPI_TX_LSB      0x08
  35 #define SPI_TX_MSB      0x0a
  36 #define SPI_RX_LSB      0x0c
  37 #define SPI_RX_MSB      0x0e
  38
  39 #define SPI_SETUP1_INT_READ_ENABLE      (1UL << 5)
  40 #define SPI_SETUP1_INT_WRITE_ENABLE     (1UL << 4)
  41 #define SPI_SETUP1_CLOCK_DIVISOR(x)     ((x) << 1)
  42 #define SPI_SETUP1_CLOCK_ENABLE         (1UL << 0)
  43
  44 #define SPI_SETUP2_ACTIVE_EDGE_FALLING  (0UL << 0)
  45 #define SPI_SETUP2_ACTIVE_EDGE_RISING   (1UL << 0)
  46 #define SPI_SETUP2_NEGATIVE_LEVEL       (0UL << 5)
  47 #define SPI_SETUP2_POSITIVE_LEVEL       (1UL << 5)
  48 #define SPI_SETUP2_LEVEL_TRIGGER        (0UL << 10)
  49 #define SPI_SETUP2_EDGE_TRIGGER         (1UL << 10)
  50
  51 #define SPI_CTRL_SEN(x)                 ((x) << 7)
  52 #define SPI_CTRL_WORD_SIZE(x)           (((x) - 1) << 2)
  53 #define SPI_CTRL_WR                     (1UL << 1)
  54 #define SPI_CTRL_RD                     (1UL << 0)
  55
  56 #define SPI_STATUS_WE                   (1UL << 1)
  57 #define SPI_STATUS_RD                   (1UL << 0)
  58
  59 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
  60  * cache operations; better heuristics consider wordsize and bitrate.
  61  */
  62 #define DMA_MIN_BYTES                   8
  63
  64 #define SPI_RUNNING     0
  65 #define SPI_SHUTDOWN    1
  66
  67 struct omap1_spi100k {
  68         struct clk              *ick;
  69         struct clk              *fck;
  70
  71         /* Virtual base address of the controller */
  72         void __iomem            *base;
  73 };
  74
  75 struct omap1_spi100k_cs {
  76         void __iomem            *base;
  77         int                     word_len;
  78 };
  79
  80 static void spi100k_enable_clock(struct spi_master *master)
  81 {
  82         unsigned int val;
  83         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
  84
  85         /* enable SPI */
  86         val = readw(spi100k->base + SPI_SETUP1);
  87         val |= SPI_SETUP1_CLOCK_ENABLE;
  88         writew(val, spi100k->base + SPI_SETUP1);
  89 }
  90
  91 static void spi100k_disable_clock(struct spi_master *master)
  92 {
  93         unsigned int val;
  94         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
  95
  96         /* disable SPI */
  97         val = readw(spi100k->base + SPI_SETUP1);
  98         val &= ~SPI_SETUP1_CLOCK_ENABLE;
  99         writew(val, spi100k->base + SPI_SETUP1);
 100 }
 101
 102 static void spi100k_write_data(struct spi_master *master, int len, int data)
 103 {
 104         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 105
 106         /* write 16-bit word, shifting 8-bit data if necessary */
 107         if (len <= 8) {
 108                 data <<= 8;
 109                 len = 16;
 110         }
 111
 112         spi100k_enable_clock(master);
 113         writew(data, spi100k->base + SPI_TX_MSB);
 114
 115         writew(SPI_CTRL_SEN(0) |
 116                SPI_CTRL_WORD_SIZE(len) |
 117                SPI_CTRL_WR,
 118                spi100k->base + SPI_CTRL);
 119
 120         /* Wait for bit ack send change */
 121         while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE)
 122                 ;
 123         udelay(1000);
 124
 125         spi100k_disable_clock(master);
 126 }
 127
 128 static int spi100k_read_data(struct spi_master *master, int len)
 129 {
 130         int dataL;
 131         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 132
 133         /* Always do at least 16 bits */
 134         if (len <= 8)
 135                 len = 16;
 136
 137         spi100k_enable_clock(master);
 138         writew(SPI_CTRL_SEN(0) |
 139                SPI_CTRL_WORD_SIZE(len) |
 140                SPI_CTRL_RD,
 141                spi100k->base + SPI_CTRL);
 142
 143         while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD)
 144                 ;
 145         udelay(1000);
 146
 147         dataL = readw(spi100k->base + SPI_RX_LSB);
 148         readw(spi100k->base + SPI_RX_MSB);
 149         spi100k_disable_clock(master);
 150
 151         return dataL;
 152 }
 153
 154 static void spi100k_open(struct spi_master *master)
 155 {
 156         /* get control of SPI */
 157         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 158
 159         writew(SPI_SETUP1_INT_READ_ENABLE |
 160                SPI_SETUP1_INT_WRITE_ENABLE |
 161                SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);
 162
 163         /* configure clock and interrupts */
 164         writew(SPI_SETUP2_ACTIVE_EDGE_FALLING |
 165                SPI_SETUP2_NEGATIVE_LEVEL |
 166                SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
 167 }
 168
 169 static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
 170 {
 171         if (enable)
 172                 writew(0x05fc, spi100k->base + SPI_CTRL);
 173         else
 174                 writew(0x05fd, spi100k->base + SPI_CTRL);
 175 }
 176
 177 static unsigned
 178 omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 179 {
 180         struct omap1_spi100k_cs *cs = spi->controller_state;
 181         unsigned int            count, c;
 182         int                     word_len;
 183
 184         count = xfer->len;
 185         c = count;
 186         word_len = cs->word_len;
 187
 188         if (word_len <= 8) {
 189                 u8              *rx;
 190                 const u8        *tx;
 191
 192                 rx = xfer->rx_buf;
 193                 tx = xfer->tx_buf;
 194                 do {
 195                         c -= 1;
 196                         if (xfer->tx_buf != NULL)
 197                                 spi100k_write_data(spi->master, word_len, *tx++);
 198                         if (xfer->rx_buf != NULL)
 199                                 *rx++ = spi100k_read_data(spi->master, word_len);
 200                 } while (c);
 201         } else if (word_len <= 16) {
 202                 u16             *rx;
 203                 const u16       *tx;
 204
 205                 rx = xfer->rx_buf;
 206                 tx = xfer->tx_buf;
 207                 do {
 208                         c -= 2;
 209                         if (xfer->tx_buf != NULL)
 210                                 spi100k_write_data(spi->master, word_len, *tx++);
 211                         if (xfer->rx_buf != NULL)
 212                                 *rx++ = spi100k_read_data(spi->master, word_len);
 213                 } while (c);
 214         } else if (word_len <= 32) {
 215                 u32             *rx;
 216                 const u32       *tx;
 217
 218                 rx = xfer->rx_buf;
 219                 tx = xfer->tx_buf;
 220                 do {
 221                         c -= 4;
 222                         if (xfer->tx_buf != NULL)
 223                                 spi100k_write_data(spi->master, word_len, *tx);
 224                         if (xfer->rx_buf != NULL)
 225                                 *rx = spi100k_read_data(spi->master, word_len);
 226                 } while (c);
 227         }
 228         return count - c;
 229 }
 230
 231 /* called only when no transfer is active to this device */
 232 static int omap1_spi100k_setup_transfer(struct spi_device *spi,
 233                 struct spi_transfer *t)
 234 {
 235         struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
 236         struct omap1_spi100k_cs *cs = spi->controller_state;
 237         u8 word_len;
 238
 239         if (t != NULL)
 240                 word_len = t->bits_per_word;
 241         else
 242                 word_len = spi->bits_per_word;
 243
 244         if (word_len > 32)
 245                 return -EINVAL;
 246         cs->word_len = word_len;
 247
 248         /* SPI init before transfer */
 249         writew(0x3e, spi100k->base + SPI_SETUP1);
 250         writew(0x00, spi100k->base + SPI_STATUS);
 251         writew(0x3e, spi100k->base + SPI_CTRL);
 252
 253         return 0;
 254 }
 255
 256 /* the spi->mode bits understood by this driver: */
 257 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 258
 259 static int omap1_spi100k_setup(struct spi_device *spi)
 260 {
 261         int                     ret;
 262         struct omap1_spi100k    *spi100k;
 263         struct omap1_spi100k_cs *cs = spi->controller_state;
 264
 265         spi100k = spi_master_get_devdata(spi->master);
 266
 267         if (!cs) {
 268                 cs = devm_kzalloc(&spi->dev, sizeof(*cs), GFP_KERNEL);
 269                 if (!cs)
 270                         return -ENOMEM;
 271                 cs->base = spi100k->base + spi->chip_select * 0x14;
 272                 spi->controller_state = cs;
 273         }
 274
 275         spi100k_open(spi->master);
 276
 277         clk_prepare_enable(spi100k->ick);
 278         clk_prepare_enable(spi100k->fck);
 279
 280         ret = omap1_spi100k_setup_transfer(spi, NULL);
 281
 282         clk_disable_unprepare(spi100k->ick);
 283         clk_disable_unprepare(spi100k->fck);
 284
 285         return ret;
 286 }
 287
 288 static int omap1_spi100k_transfer_one_message(struct spi_master *master,
 289                                               struct spi_message *m)
 290 {
 291         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 292         struct spi_device *spi = m->spi;
 293         struct spi_transfer *t = NULL;
 294         int cs_active = 0;
 295         int status = 0;
 296
 297         list_for_each_entry(t, &m->transfers, transfer_list) {
 298                 if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
 299                         break;
 300                 }
 301                 status = omap1_spi100k_setup_transfer(spi, t);
 302                 if (status < 0)
 303                         break;
 304
 305                 if (!cs_active) {
 306                         omap1_spi100k_force_cs(spi100k, 1);
 307                         cs_active = 1;
 308                 }
 309
 310                 if (t->len) {
 311                         unsigned count;
 312
 313                         count = omap1_spi100k_txrx_pio(spi, t);
 314                         m->actual_length += count;
 315
 316                         if (count != t->len) {
 317                                 break;
 318                         }
 319                 }
 320
 321                 spi_transfer_delay_exec(t);
 322
 323                 /* ignore the "leave it on after last xfer" hint */
 324
 325                 if (t->cs_change) {
 326                         omap1_spi100k_force_cs(spi100k, 0);
 327                         cs_active = 0;
 328                 }
 329         }
 330
 331         status = omap1_spi100k_setup_transfer(spi, NULL);
 332
 333         if (cs_active)
 334                 omap1_spi100k_force_cs(spi100k, 0);
 335
 336         m->status = status;
 337
 338         spi_finalize_current_message(master);
 339
 340         return status;
 341 }
 342
 343 static int omap1_spi100k_probe(struct platform_device *pdev)
 344 {
 345         struct spi_master       *master;
 346         struct omap1_spi100k    *spi100k;
 347         int                     status = 0;
 348
 349         if (!pdev->id)
 350                 return -EINVAL;
 351
 352         master = spi_alloc_master(&pdev->dev, sizeof(*spi100k));
 353         if (master == NULL) {
 354                 dev_dbg(&pdev->dev, "master allocation failed\n");
 355                 return -ENOMEM;
 356         }
 357
 358         if (pdev->id != -1)
 359                 master->bus_num = pdev->id;
 360
 361         master->setup = omap1_spi100k_setup;
 362         master->transfer_one_message = omap1_spi100k_transfer_one_message;
 363         master->num_chipselect = 2;
 364         master->mode_bits = MODEBITS;
 365         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
 366         master->min_speed_hz = OMAP1_SPI100K_MAX_FREQ/(1<<16);
 367         master->max_speed_hz = OMAP1_SPI100K_MAX_FREQ;
 368         master->auto_runtime_pm = true;
 369
 370         spi100k = spi_master_get_devdata(master);
 371
 372         /*
 373          * The memory region base address is taken as the platform_data.
 374          * You should allocate this with ioremap() before initializing
 375          * the SPI.
 376          */
 377         spi100k->base = (void __iomem *)dev_get_platdata(&pdev->dev);
 378
 379         spi100k->ick = devm_clk_get(&pdev->dev, "ick");
 380         if (IS_ERR(spi100k->ick)) {
 381                 dev_dbg(&pdev->dev, "can't get spi100k_ick\n");
 382                 status = PTR_ERR(spi100k->ick);
 383                 goto err;
 384         }
 385
 386         spi100k->fck = devm_clk_get(&pdev->dev, "fck");
 387         if (IS_ERR(spi100k->fck)) {
 388                 dev_dbg(&pdev->dev, "can't get spi100k_fck\n");
 389                 status = PTR_ERR(spi100k->fck);
 390                 goto err;
 391         }
 392
 393         status = clk_prepare_enable(spi100k->ick);
 394         if (status != 0) {
 395                 dev_err(&pdev->dev, "failed to enable ick: %d\n", status);
 396                 goto err;
 397         }
 398
 399         status = clk_prepare_enable(spi100k->fck);
 400         if (status != 0) {
 401                 dev_err(&pdev->dev, "failed to enable fck: %d\n", status);
 402                 goto err_ick;
 403         }
 404
 405         pm_runtime_enable(&pdev->dev);
 406         pm_runtime_set_active(&pdev->dev);
 407
 408         status = devm_spi_register_master(&pdev->dev, master);
 409         if (status < 0)
 410                 goto err_fck;
 411
 412         return status;
 413
 414 err_fck:
 415         clk_disable_unprepare(spi100k->fck);
 416 err_ick:
 417         clk_disable_unprepare(spi100k->ick);
 418 err:
 419         spi_master_put(master);
 420         return status;
 421 }
 422
 423 static int omap1_spi100k_remove(struct platform_device *pdev)
 424 {
 425         struct spi_master *master = platform_get_drvdata(pdev);
 426         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 427
 428         pm_runtime_disable(&pdev->dev);
 429
 430         clk_disable_unprepare(spi100k->fck);
 431         clk_disable_unprepare(spi100k->ick);
 432
 433         return 0;
 434 }
 435
 436 #ifdef CONFIG_PM
 437 static int omap1_spi100k_runtime_suspend(struct device *dev)
 438 {
 439         struct spi_master *master = dev_get_drvdata(dev);
 440         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 441
 442         clk_disable_unprepare(spi100k->ick);
 443         clk_disable_unprepare(spi100k->fck);
 444
 445         return 0;
 446 }
 447
 448 static int omap1_spi100k_runtime_resume(struct device *dev)
 449 {
 450         struct spi_master *master = dev_get_drvdata(dev);
 451         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 452         int ret;
 453
 454         ret = clk_prepare_enable(spi100k->ick);
 455         if (ret != 0) {
 456                 dev_err(dev, "Failed to enable ick: %d\n", ret);
 457                 return ret;
 458         }
 459
 460         ret = clk_prepare_enable(spi100k->fck);
 461         if (ret != 0) {
 462                 dev_err(dev, "Failed to enable fck: %d\n", ret);
 463                 clk_disable_unprepare(spi100k->ick);
 464                 return ret;
 465         }
 466
 467         return 0;
 468 }
 469 #endif
 470
 471 static const struct dev_pm_ops omap1_spi100k_pm = {
 472         SET_RUNTIME_PM_OPS(omap1_spi100k_runtime_suspend,
 473                            omap1_spi100k_runtime_resume, NULL)
 474 };
 475
 476 static struct platform_driver omap1_spi100k_driver = {
 477         .driver = {
 478                 .name           = "omap1_spi100k",
 479                 .pm             = &omap1_spi100k_pm,
 480         },
 481         .probe          = omap1_spi100k_probe,
 482         .remove         = omap1_spi100k_remove,
 483 };
 484
 485 module_platform_driver(omap1_spi100k_driver);
 486
 487 MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver");
 488 MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>");
 489 MODULE_LICENSE("GPL");