drivers/spi/spi-efm32.c

   1 /*
   2  * Copyright (C) 2012-2013 Uwe Kleine-Koenig for Pengutronix
   3  *
   4  * This program is free software; you can redistribute it and/or modify it under
   5  * the terms of the GNU General Public License version 2 as published by the
   6  * Free Software Foundation.
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/io.h>
  10 #include <linux/spi/spi.h>
  11 #include <linux/spi/spi_bitbang.h>
  12 #include <linux/gpio.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/clk.h>
  16 #include <linux/err.h>
  17 #include <linux/module.h>
  18 #include <linux/of_gpio.h>
  19 #include <linux/platform_data/efm32-spi.h>
  20
  21 #define DRIVER_NAME "efm32-spi"
  22
  23 #define MASK_VAL(mask, val)             ((val << __ffs(mask)) & mask)
  24
  25 #define REG_CTRL                0x00
  26 #define REG_CTRL_SYNC                   0x0001
  27 #define REG_CTRL_CLKPOL                 0x0100
  28 #define REG_CTRL_CLKPHA                 0x0200
  29 #define REG_CTRL_MSBF                   0x0400
  30 #define REG_CTRL_TXBIL                  0x1000
  31
  32 #define REG_FRAME               0x04
  33 #define REG_FRAME_DATABITS__MASK        0x000f
  34 #define REG_FRAME_DATABITS(n)           ((n) - 3)
  35
  36 #define REG_CMD                 0x0c
  37 #define REG_CMD_RXEN                    0x0001
  38 #define REG_CMD_RXDIS                   0x0002
  39 #define REG_CMD_TXEN                    0x0004
  40 #define REG_CMD_TXDIS                   0x0008
  41 #define REG_CMD_MASTEREN                0x0010
  42
  43 #define REG_STATUS              0x10
  44 #define REG_STATUS_TXENS                0x0002
  45 #define REG_STATUS_TXC                  0x0020
  46 #define REG_STATUS_TXBL                 0x0040
  47 #define REG_STATUS_RXDATAV              0x0080
  48
  49 #define REG_CLKDIV              0x14
  50
  51 #define REG_RXDATAX             0x18
  52 #define REG_RXDATAX_RXDATA__MASK        0x01ff
  53 #define REG_RXDATAX_PERR                0x4000
  54 #define REG_RXDATAX_FERR                0x8000
  55
  56 #define REG_TXDATA              0x34
  57
  58 #define REG_IF          0x40
  59 #define REG_IF_TXBL                     0x0002
  60 #define REG_IF_RXDATAV                  0x0004
  61
  62 #define REG_IFS         0x44
  63 #define REG_IFC         0x48
  64 #define REG_IEN         0x4c
  65
  66 #define REG_ROUTE               0x54
  67 #define REG_ROUTE_RXPEN                 0x0001
  68 #define REG_ROUTE_TXPEN                 0x0002
  69 #define REG_ROUTE_CLKPEN                0x0008
  70 #define REG_ROUTE_LOCATION__MASK        0x0700
  71 #define REG_ROUTE_LOCATION(n)           MASK_VAL(REG_ROUTE_LOCATION__MASK, (n))
  72
  73 struct efm32_spi_ddata {
  74         struct spi_bitbang bitbang;
  75
  76         spinlock_t lock;
  77
  78         struct clk *clk;
  79         void __iomem *base;
  80         unsigned int rxirq, txirq;
  81         struct efm32_spi_pdata pdata;
  82
  83         /* irq data */
  84         struct completion done;
  85         const u8 *tx_buf;
  86         u8 *rx_buf;
  87         unsigned tx_len, rx_len;
  88
  89         /* chip selects */
  90         unsigned csgpio[];
  91 };
  92
  93 #define ddata_to_dev(ddata)     (&(ddata->bitbang.master->dev))
  94 #define efm32_spi_vdbg(ddata, format, arg...)   \
  95         dev_vdbg(ddata_to_dev(ddata), format, ##arg)
  96
  97 static void efm32_spi_write32(struct efm32_spi_ddata *ddata,
  98                 u32 value, unsigned offset)
  99 {
 100         writel_relaxed(value, ddata->base + offset);
 101 }
 102
 103 static u32 efm32_spi_read32(struct efm32_spi_ddata *ddata, unsigned offset)
 104 {
 105         return readl_relaxed(ddata->base + offset);
 106 }
 107
 108 static void efm32_spi_chipselect(struct spi_device *spi, int is_on)
 109 {
 110         struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
 111         int value = !(spi->mode & SPI_CS_HIGH) == !(is_on == BITBANG_CS_ACTIVE);
 112
 113         gpio_set_value(ddata->csgpio[spi->chip_select], value);
 114 }
 115
 116 static int efm32_spi_setup_transfer(struct spi_device *spi,
 117                 struct spi_transfer *t)
 118 {
 119         struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
 120
 121         unsigned bpw = t->bits_per_word ?: spi->bits_per_word;
 122         unsigned speed = t->speed_hz ?: spi->max_speed_hz;
 123         unsigned long clkfreq = clk_get_rate(ddata->clk);
 124         u32 clkdiv;
 125
 126         efm32_spi_write32(ddata, REG_CTRL_SYNC | REG_CTRL_MSBF |
 127                         (spi->mode & SPI_CPHA ? REG_CTRL_CLKPHA : 0) |
 128                         (spi->mode & SPI_CPOL ? REG_CTRL_CLKPOL : 0), REG_CTRL);
 129
 130         efm32_spi_write32(ddata,
 131                         REG_FRAME_DATABITS(bpw), REG_FRAME);
 132
 133         if (2 * speed >= clkfreq)
 134                 clkdiv = 0;
 135         else
 136                 clkdiv = 64 * (DIV_ROUND_UP(2 * clkfreq, speed) - 4);
 137
 138         if (clkdiv > (1U << 21))
 139                 return -EINVAL;
 140
 141         efm32_spi_write32(ddata, clkdiv, REG_CLKDIV);
 142         efm32_spi_write32(ddata, REG_CMD_MASTEREN, REG_CMD);
 143         efm32_spi_write32(ddata, REG_CMD_RXEN | REG_CMD_TXEN, REG_CMD);
 144
 145         return 0;
 146 }
 147
 148 static void efm32_spi_tx_u8(struct efm32_spi_ddata *ddata)
 149 {
 150         u8 val = 0;
 151
 152         if (ddata->tx_buf) {
 153                 val = *ddata->tx_buf;
 154                 ddata->tx_buf++;
 155         }
 156
 157         ddata->tx_len--;
 158         efm32_spi_write32(ddata, val, REG_TXDATA);
 159         efm32_spi_vdbg(ddata, "%s: tx 0x%x\n", __func__, val);
 160 }
 161
 162 static void efm32_spi_rx_u8(struct efm32_spi_ddata *ddata)
 163 {
 164         u32 rxdata = efm32_spi_read32(ddata, REG_RXDATAX);
 165         efm32_spi_vdbg(ddata, "%s: rx 0x%x\n", __func__, rxdata);
 166
 167         if (ddata->rx_buf) {
 168                 *ddata->rx_buf = rxdata;
 169                 ddata->rx_buf++;
 170         }
 171
 172         ddata->rx_len--;
 173 }
 174
 175 static void efm32_spi_filltx(struct efm32_spi_ddata *ddata)
 176 {
 177         while (ddata->tx_len &&
 178                         ddata->tx_len + 2 > ddata->rx_len &&
 179                         efm32_spi_read32(ddata, REG_STATUS) & REG_STATUS_TXBL) {
 180                 efm32_spi_tx_u8(ddata);
 181         }
 182 }
 183
 184 static int efm32_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
 185 {
 186         struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
 187         int ret = -EBUSY;
 188
 189         spin_lock_irq(&ddata->lock);
 190
 191         if (ddata->tx_buf || ddata->rx_buf)
 192                 goto out_unlock;
 193
 194         ddata->tx_buf = t->tx_buf;
 195         ddata->rx_buf = t->rx_buf;
 196         ddata->tx_len = ddata->rx_len =
 197                 t->len * DIV_ROUND_UP(t->bits_per_word, 8);
 198
 199         efm32_spi_filltx(ddata);
 200
 201         init_completion(&ddata->done);
 202
 203         efm32_spi_write32(ddata, REG_IF_TXBL | REG_IF_RXDATAV, REG_IEN);
 204
 205         spin_unlock_irq(&ddata->lock);
 206
 207         wait_for_completion(&ddata->done);
 208
 209         spin_lock_irq(&ddata->lock);
 210
 211         ret = t->len - max(ddata->tx_len, ddata->rx_len);
 212
 213         efm32_spi_write32(ddata, 0, REG_IEN);
 214         ddata->tx_buf = ddata->rx_buf = NULL;
 215
 216 out_unlock:
 217         spin_unlock_irq(&ddata->lock);
 218
 219         return ret;
 220 }
 221
 222 static irqreturn_t efm32_spi_rxirq(int irq, void *data)
 223 {
 224         struct efm32_spi_ddata *ddata = data;
 225         irqreturn_t ret = IRQ_NONE;
 226
 227         spin_lock(&ddata->lock);
 228
 229         while (ddata->rx_len > 0 &&
 230                         efm32_spi_read32(ddata, REG_STATUS) &
 231                         REG_STATUS_RXDATAV) {
 232                 efm32_spi_rx_u8(ddata);
 233
 234                 ret = IRQ_HANDLED;
 235         }
 236
 237         if (!ddata->rx_len) {
 238                 u32 ien = efm32_spi_read32(ddata, REG_IEN);
 239
 240                 ien &= ~REG_IF_RXDATAV;
 241
 242                 efm32_spi_write32(ddata, ien, REG_IEN);
 243
 244                 complete(&ddata->done);
 245         }
 246
 247         spin_unlock(&ddata->lock);
 248
 249         return ret;
 250 }
 251
 252 static irqreturn_t efm32_spi_txirq(int irq, void *data)
 253 {
 254         struct efm32_spi_ddata *ddata = data;
 255
 256         efm32_spi_vdbg(ddata,
 257                         "%s: txlen = %u, rxlen = %u, if=0x%08x, stat=0x%08x\n",
 258                         __func__, ddata->tx_len, ddata->rx_len,
 259                         efm32_spi_read32(ddata, REG_IF),
 260                         efm32_spi_read32(ddata, REG_STATUS));
 261
 262         spin_lock(&ddata->lock);
 263
 264         efm32_spi_filltx(ddata);
 265
 266         efm32_spi_vdbg(ddata, "%s: txlen = %u, rxlen = %u\n",
 267                         __func__, ddata->tx_len, ddata->rx_len);
 268
 269         if (!ddata->tx_len) {
 270                 u32 ien = efm32_spi_read32(ddata, REG_IEN);
 271
 272                 ien &= ~REG_IF_TXBL;
 273
 274                 efm32_spi_write32(ddata, ien, REG_IEN);
 275                 efm32_spi_vdbg(ddata, "disable TXBL\n");
 276         }
 277
 278         spin_unlock(&ddata->lock);
 279
 280         return IRQ_HANDLED;
 281 }
 282
 283 static u32 efm32_spi_get_configured_location(struct efm32_spi_ddata *ddata)
 284 {
 285         u32 reg = efm32_spi_read32(ddata, REG_ROUTE);
 286
 287         return (reg & REG_ROUTE_LOCATION__MASK) >> __ffs(REG_ROUTE_LOCATION__MASK);
 288 }
 289
 290 static int efm32_spi_probe_dt(struct platform_device *pdev,
 291                 struct spi_master *master, struct efm32_spi_ddata *ddata)
 292 {
 293         struct device_node *np = pdev->dev.of_node;
 294         u32 location;
 295         int ret;
 296
 297         if (!np)
 298                 return 1;
 299
 300         ret = of_property_read_u32(np, "location", &location);
 301         if (!ret) {
 302                 dev_dbg(&pdev->dev, "using location %u\n", location);
 303         } else {
 304                 /* default to location configured in hardware */
 305                 location = efm32_spi_get_configured_location(ddata);
 306
 307                 dev_info(&pdev->dev, "fall back to location %u\n", location);
 308         }
 309
 310         ddata->pdata.location = location;
 311
 312         /* spi core takes care about the bus number using an alias */
 313         master->bus_num = -1;
 314
 315         return 0;
 316 }
 317
 318 static int efm32_spi_probe(struct platform_device *pdev)
 319 {
 320         struct efm32_spi_ddata *ddata;
 321         struct resource *res;
 322         int ret;
 323         struct spi_master *master;
 324         struct device_node *np = pdev->dev.of_node;
 325         unsigned int num_cs, i;
 326
 327         num_cs = of_gpio_named_count(np, "cs-gpios");
 328
 329         master = spi_alloc_master(&pdev->dev,
 330                         sizeof(*ddata) + num_cs * sizeof(unsigned));
 331         if (!master) {
 332                 dev_dbg(&pdev->dev,
 333                                 "failed to allocate spi master controller\n");
 334                 return -ENOMEM;
 335         }
 336         platform_set_drvdata(pdev, master);
 337
 338         master->dev.of_node = pdev->dev.of_node;
 339
 340         master->num_chipselect = num_cs;
 341         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 342         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
 343
 344         ddata = spi_master_get_devdata(master);
 345
 346         ddata->bitbang.master = master;
 347         ddata->bitbang.chipselect = efm32_spi_chipselect;
 348         ddata->bitbang.setup_transfer = efm32_spi_setup_transfer;
 349         ddata->bitbang.txrx_bufs = efm32_spi_txrx_bufs;
 350
 351         spin_lock_init(&ddata->lock);
 352
 353         ddata->clk = devm_clk_get(&pdev->dev, NULL);
 354         if (IS_ERR(ddata->clk)) {
 355                 ret = PTR_ERR(ddata->clk);
 356                 dev_err(&pdev->dev, "failed to get clock: %d\n", ret);
 357                 goto err;
 358         }
 359
 360         for (i = 0; i < num_cs; ++i) {
 361                 ret = of_get_named_gpio(np, "cs-gpios", i);
 362                 if (ret < 0) {
 363                         dev_err(&pdev->dev, "failed to get csgpio#%u (%d)\n",
 364                                         i, ret);
 365                         goto err;
 366                 }
 367                 ddata->csgpio[i] = ret;
 368                 dev_dbg(&pdev->dev, "csgpio#%u = %u\n", i, ddata->csgpio[i]);
 369                 ret = devm_gpio_request_one(&pdev->dev, ddata->csgpio[i],
 370                                 GPIOF_OUT_INIT_LOW, DRIVER_NAME);
 371                 if (ret < 0) {
 372                         dev_err(&pdev->dev,
 373                                         "failed to configure csgpio#%u (%d)\n",
 374                                         i, ret);
 375                         goto err;
 376                 }
 377         }
 378
 379         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 380         if (!res) {
 381                 ret = -ENODEV;
 382                 dev_err(&pdev->dev, "failed to determine base address\n");
 383                 goto err;
 384         }
 385
 386         if (resource_size(res) < 0x60) {
 387                 ret = -EINVAL;
 388                 dev_err(&pdev->dev, "memory resource too small\n");
 389                 goto err;
 390         }
 391
 392         ddata->base = devm_ioremap_resource(&pdev->dev, res);
 393         if (IS_ERR(ddata->base)) {
 394                 ret = PTR_ERR(ddata->base);
 395                 goto err;
 396         }
 397
 398         ret = platform_get_irq(pdev, 0);
 399         if (ret <= 0) {
 400                 dev_err(&pdev->dev, "failed to get rx irq (%d)\n", ret);
 401                 goto err;
 402         }
 403
 404         ddata->rxirq = ret;
 405
 406         ret = platform_get_irq(pdev, 1);
 407         if (ret <= 0)
 408                 ret = ddata->rxirq + 1;
 409
 410         ddata->txirq = ret;
 411
 412         ret = clk_prepare_enable(ddata->clk);
 413         if (ret < 0) {
 414                 dev_err(&pdev->dev, "failed to enable clock (%d)\n", ret);
 415                 goto err;
 416         }
 417
 418         ret = efm32_spi_probe_dt(pdev, master, ddata);
 419         if (ret > 0) {
 420                 /* not created by device tree */
 421                 const struct efm32_spi_pdata *pdata =
 422                         dev_get_platdata(&pdev->dev);
 423
 424                 if (pdata)
 425                         ddata->pdata = *pdata;
 426                 else
 427                         ddata->pdata.location =
 428                                 efm32_spi_get_configured_location(ddata);
 429
 430                 master->bus_num = pdev->id;
 431
 432         } else if (ret < 0) {
 433                 goto err_disable_clk;
 434         }
 435
 436         efm32_spi_write32(ddata, 0, REG_IEN);
 437         efm32_spi_write32(ddata, REG_ROUTE_TXPEN | REG_ROUTE_RXPEN |
 438                         REG_ROUTE_CLKPEN |
 439                         REG_ROUTE_LOCATION(ddata->pdata.location), REG_ROUTE);
 440
 441         ret = request_irq(ddata->rxirq, efm32_spi_rxirq,
 442                         0, DRIVER_NAME " rx", ddata);
 443         if (ret) {
 444                 dev_err(&pdev->dev, "failed to register rxirq (%d)\n", ret);
 445                 goto err_disable_clk;
 446         }
 447
 448         ret = request_irq(ddata->txirq, efm32_spi_txirq,
 449                         0, DRIVER_NAME " tx", ddata);
 450         if (ret) {
 451                 dev_err(&pdev->dev, "failed to register txirq (%d)\n", ret);
 452                 goto err_free_rx_irq;
 453         }
 454
 455         ret = spi_bitbang_start(&ddata->bitbang);
 456         if (ret) {
 457                 dev_err(&pdev->dev, "spi_bitbang_start failed (%d)\n", ret);
 458
 459                 free_irq(ddata->txirq, ddata);
 460 err_free_rx_irq:
 461                 free_irq(ddata->rxirq, ddata);
 462 err_disable_clk:
 463                 clk_disable_unprepare(ddata->clk);
 464 err:
 465                 spi_master_put(master);
 466         }
 467
 468         return ret;
 469 }
 470
 471 static int efm32_spi_remove(struct platform_device *pdev)
 472 {
 473         struct spi_master *master = platform_get_drvdata(pdev);
 474         struct efm32_spi_ddata *ddata = spi_master_get_devdata(master);
 475
 476         spi_bitbang_stop(&ddata->bitbang);
 477
 478         efm32_spi_write32(ddata, 0, REG_IEN);
 479
 480         free_irq(ddata->txirq, ddata);
 481         free_irq(ddata->rxirq, ddata);
 482         clk_disable_unprepare(ddata->clk);
 483         spi_master_put(master);
 484
 485         return 0;
 486 }
 487
 488 static const struct of_device_id efm32_spi_dt_ids[] = {
 489         {
 490                 .compatible = "efm32,spi",
 491         }, {
 492                 /* sentinel */
 493         }
 494 };
 495 MODULE_DEVICE_TABLE(of, efm32_spi_dt_ids);
 496
 497 static struct platform_driver efm32_spi_driver = {
 498         .probe = efm32_spi_probe,
 499         .remove = efm32_spi_remove,
 500
 501         .driver = {
 502                 .name = DRIVER_NAME,
 503                 .owner = THIS_MODULE,
 504                 .of_match_table = efm32_spi_dt_ids,
 505         },
 506 };
 507 module_platform_driver(efm32_spi_driver);
 508
 509 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
 510 MODULE_DESCRIPTION("EFM32 SPI driver");
 511 MODULE_LICENSE("GPL v2");
 512 MODULE_ALIAS("platform:" DRIVER_NAME);