drivers/spi/spi-nuc900.c

   1 /*
   2  * Copyright (c) 2009 Nuvoton technology.
   3  * Wan ZongShun <mcuos.com@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/workqueue.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/delay.h>
  17 #include <linux/errno.h>
  18 #include <linux/err.h>
  19 #include <linux/clk.h>
  20 #include <linux/device.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/gpio.h>
  23 #include <linux/io.h>
  24 #include <linux/slab.h>
  25
  26 #include <linux/spi/spi.h>
  27 #include <linux/spi/spi_bitbang.h>
  28
  29 #include <linux/platform_data/spi-nuc900.h>
  30
  31 /* usi registers offset */
  32 #define USI_CNT         0x00
  33 #define USI_DIV         0x04
  34 #define USI_SSR         0x08
  35 #define USI_RX0         0x10
  36 #define USI_TX0         0x10
  37
  38 /* usi register bit */
  39 #define ENINT           (0x01 << 17)
  40 #define ENFLG           (0x01 << 16)
  41 #define TXNUM           (0x03 << 8)
  42 #define TXNEG           (0x01 << 2)
  43 #define RXNEG           (0x01 << 1)
  44 #define LSB             (0x01 << 10)
  45 #define SELECTLEV       (0x01 << 2)
  46 #define SELECTPOL       (0x01 << 31)
  47 #define SELECTSLAVE     0x01
  48 #define GOBUSY          0x01
  49
  50 struct nuc900_spi {
  51         struct spi_bitbang       bitbang;
  52         struct completion        done;
  53         void __iomem            *regs;
  54         int                      irq;
  55         int                      len;
  56         int                      count;
  57         const unsigned char     *tx;
  58         unsigned char           *rx;
  59         struct clk              *clk;
  60         struct resource         *ioarea;
  61         struct spi_master       *master;
  62         struct spi_device       *curdev;
  63         struct device           *dev;
  64         struct nuc900_spi_info *pdata;
  65         spinlock_t              lock;
  66         struct resource         *res;
  67 };
  68
  69 static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
  70 {
  71         return spi_master_get_devdata(sdev->master);
  72 }
  73
  74 static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
  75 {
  76         struct nuc900_spi *hw = to_hw(spi);
  77         unsigned int val;
  78         unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
  79         unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
  80         unsigned long flags;
  81
  82         spin_lock_irqsave(&hw->lock, flags);
  83
  84         val = __raw_readl(hw->regs + USI_SSR);
  85
  86         if (!cs)
  87                 val &= ~SELECTLEV;
  88         else
  89                 val |= SELECTLEV;
  90
  91         if (!ssr)
  92                 val &= ~SELECTSLAVE;
  93         else
  94                 val |= SELECTSLAVE;
  95
  96         __raw_writel(val, hw->regs + USI_SSR);
  97
  98         val = __raw_readl(hw->regs + USI_CNT);
  99
 100         if (!cpol)
 101                 val &= ~SELECTPOL;
 102         else
 103                 val |= SELECTPOL;
 104
 105         __raw_writel(val, hw->regs + USI_CNT);
 106
 107         spin_unlock_irqrestore(&hw->lock, flags);
 108 }
 109
 110 static void nuc900_spi_chipsel(struct spi_device *spi, int value)
 111 {
 112         switch (value) {
 113         case BITBANG_CS_INACTIVE:
 114                 nuc900_slave_select(spi, 0);
 115                 break;
 116
 117         case BITBANG_CS_ACTIVE:
 118                 nuc900_slave_select(spi, 1);
 119                 break;
 120         }
 121 }
 122
 123 static void nuc900_spi_setup_txnum(struct nuc900_spi *hw,
 124                                                         unsigned int txnum)
 125 {
 126         unsigned int val;
 127         unsigned long flags;
 128
 129         spin_lock_irqsave(&hw->lock, flags);
 130
 131         val = __raw_readl(hw->regs + USI_CNT);
 132
 133         if (!txnum)
 134                 val &= ~TXNUM;
 135         else
 136                 val |= txnum << 0x08;
 137
 138         __raw_writel(val, hw->regs + USI_CNT);
 139
 140         spin_unlock_irqrestore(&hw->lock, flags);
 141
 142 }
 143
 144 static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
 145                                                         unsigned int txbitlen)
 146 {
 147         unsigned int val;
 148         unsigned long flags;
 149
 150         spin_lock_irqsave(&hw->lock, flags);
 151
 152         val = __raw_readl(hw->regs + USI_CNT);
 153
 154         val |= (txbitlen << 0x03);
 155
 156         __raw_writel(val, hw->regs + USI_CNT);
 157
 158         spin_unlock_irqrestore(&hw->lock, flags);
 159 }
 160
 161 static void nuc900_spi_gobusy(struct nuc900_spi *hw)
 162 {
 163         unsigned int val;
 164         unsigned long flags;
 165
 166         spin_lock_irqsave(&hw->lock, flags);
 167
 168         val = __raw_readl(hw->regs + USI_CNT);
 169
 170         val |= GOBUSY;
 171
 172         __raw_writel(val, hw->regs + USI_CNT);
 173
 174         spin_unlock_irqrestore(&hw->lock, flags);
 175 }
 176
 177 static int nuc900_spi_setupxfer(struct spi_device *spi,
 178                                  struct spi_transfer *t)
 179 {
 180         return 0;
 181 }
 182
 183 static int nuc900_spi_setup(struct spi_device *spi)
 184 {
 185         return 0;
 186 }
 187
 188 static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
 189 {
 190         return hw->tx ? hw->tx[count] : 0;
 191 }
 192
 193 static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
 194 {
 195         struct nuc900_spi *hw = to_hw(spi);
 196
 197         hw->tx = t->tx_buf;
 198         hw->rx = t->rx_buf;
 199         hw->len = t->len;
 200         hw->count = 0;
 201
 202         __raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);
 203
 204         nuc900_spi_gobusy(hw);
 205
 206         wait_for_completion(&hw->done);
 207
 208         return hw->count;
 209 }
 210
 211 static irqreturn_t nuc900_spi_irq(int irq, void *dev)
 212 {
 213         struct nuc900_spi *hw = dev;
 214         unsigned int status;
 215         unsigned int count = hw->count;
 216
 217         status = __raw_readl(hw->regs + USI_CNT);
 218         __raw_writel(status, hw->regs + USI_CNT);
 219
 220         if (status & ENFLG) {
 221                 hw->count++;
 222
 223                 if (hw->rx)
 224                         hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
 225                 count++;
 226
 227                 if (count < hw->len) {
 228                         __raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
 229                         nuc900_spi_gobusy(hw);
 230                 } else {
 231                         complete(&hw->done);
 232                 }
 233
 234                 return IRQ_HANDLED;
 235         }
 236
 237         complete(&hw->done);
 238         return IRQ_HANDLED;
 239 }
 240
 241 static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
 242 {
 243         unsigned int val;
 244         unsigned long flags;
 245
 246         spin_lock_irqsave(&hw->lock, flags);
 247
 248         val = __raw_readl(hw->regs + USI_CNT);
 249
 250         if (edge)
 251                 val |= TXNEG;
 252         else
 253                 val &= ~TXNEG;
 254         __raw_writel(val, hw->regs + USI_CNT);
 255
 256         spin_unlock_irqrestore(&hw->lock, flags);
 257 }
 258
 259 static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
 260 {
 261         unsigned int val;
 262         unsigned long flags;
 263
 264         spin_lock_irqsave(&hw->lock, flags);
 265
 266         val = __raw_readl(hw->regs + USI_CNT);
 267
 268         if (edge)
 269                 val |= RXNEG;
 270         else
 271                 val &= ~RXNEG;
 272         __raw_writel(val, hw->regs + USI_CNT);
 273
 274         spin_unlock_irqrestore(&hw->lock, flags);
 275 }
 276
 277 static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
 278 {
 279         unsigned int val;
 280         unsigned long flags;
 281
 282         spin_lock_irqsave(&hw->lock, flags);
 283
 284         val = __raw_readl(hw->regs + USI_CNT);
 285
 286         if (lsb)
 287                 val |= LSB;
 288         else
 289                 val &= ~LSB;
 290         __raw_writel(val, hw->regs + USI_CNT);
 291
 292         spin_unlock_irqrestore(&hw->lock, flags);
 293 }
 294
 295 static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
 296 {
 297         unsigned int val;
 298         unsigned long flags;
 299
 300         spin_lock_irqsave(&hw->lock, flags);
 301
 302         val = __raw_readl(hw->regs + USI_CNT);
 303
 304         if (sleep)
 305                 val |= (sleep << 12);
 306         else
 307                 val &= ~(0x0f << 12);
 308         __raw_writel(val, hw->regs + USI_CNT);
 309
 310         spin_unlock_irqrestore(&hw->lock, flags);
 311 }
 312
 313 static void nuc900_enable_int(struct nuc900_spi *hw)
 314 {
 315         unsigned int val;
 316         unsigned long flags;
 317
 318         spin_lock_irqsave(&hw->lock, flags);
 319
 320         val = __raw_readl(hw->regs + USI_CNT);
 321
 322         val |= ENINT;
 323
 324         __raw_writel(val, hw->regs + USI_CNT);
 325
 326         spin_unlock_irqrestore(&hw->lock, flags);
 327 }
 328
 329 static void nuc900_set_divider(struct nuc900_spi *hw)
 330 {
 331         __raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
 332 }
 333
 334 static void nuc900_init_spi(struct nuc900_spi *hw)
 335 {
 336         clk_enable(hw->clk);
 337         spin_lock_init(&hw->lock);
 338
 339         nuc900_tx_edge(hw, hw->pdata->txneg);
 340         nuc900_rx_edge(hw, hw->pdata->rxneg);
 341         nuc900_send_first(hw, hw->pdata->lsb);
 342         nuc900_set_sleep(hw, hw->pdata->sleep);
 343         nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
 344         nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
 345         nuc900_set_divider(hw);
 346         nuc900_enable_int(hw);
 347 }
 348
 349 static int nuc900_spi_probe(struct platform_device *pdev)
 350 {
 351         struct nuc900_spi *hw;
 352         struct spi_master *master;
 353         int err = 0;
 354
 355         master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
 356         if (master == NULL) {
 357                 dev_err(&pdev->dev, "No memory for spi_master\n");
 358                 err = -ENOMEM;
 359                 goto err_nomem;
 360         }
 361
 362         hw = spi_master_get_devdata(master);
 363         hw->master = spi_master_get(master);
 364         hw->pdata  = pdev->dev.platform_data;
 365         hw->dev = &pdev->dev;
 366
 367         if (hw->pdata == NULL) {
 368                 dev_err(&pdev->dev, "No platform data supplied\n");
 369                 err = -ENOENT;
 370                 goto err_pdata;
 371         }
 372
 373         platform_set_drvdata(pdev, hw);
 374         init_completion(&hw->done);
 375
 376         master->mode_bits          = SPI_MODE_0;
 377         master->num_chipselect     = hw->pdata->num_cs;
 378         master->bus_num            = hw->pdata->bus_num;
 379         hw->bitbang.master         = hw->master;
 380         hw->bitbang.setup_transfer = nuc900_spi_setupxfer;
 381         hw->bitbang.chipselect     = nuc900_spi_chipsel;
 382         hw->bitbang.txrx_bufs      = nuc900_spi_txrx;
 383         hw->bitbang.master->setup  = nuc900_spi_setup;
 384
 385         hw->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 386         if (hw->res == NULL) {
 387                 dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
 388                 err = -ENOENT;
 389                 goto err_pdata;
 390         }
 391
 392         hw->ioarea = request_mem_region(hw->res->start,
 393                                         resource_size(hw->res), pdev->name);
 394
 395         if (hw->ioarea == NULL) {
 396                 dev_err(&pdev->dev, "Cannot reserve region\n");
 397                 err = -ENXIO;
 398                 goto err_pdata;
 399         }
 400
 401         hw->regs = ioremap(hw->res->start, resource_size(hw->res));
 402         if (hw->regs == NULL) {
 403                 dev_err(&pdev->dev, "Cannot map IO\n");
 404                 err = -ENXIO;
 405                 goto err_iomap;
 406         }
 407
 408         hw->irq = platform_get_irq(pdev, 0);
 409         if (hw->irq < 0) {
 410                 dev_err(&pdev->dev, "No IRQ specified\n");
 411                 err = -ENOENT;
 412                 goto err_irq;
 413         }
 414
 415         err = request_irq(hw->irq, nuc900_spi_irq, 0, pdev->name, hw);
 416         if (err) {
 417                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
 418                 goto err_irq;
 419         }
 420
 421         hw->clk = clk_get(&pdev->dev, "spi");
 422         if (IS_ERR(hw->clk)) {
 423                 dev_err(&pdev->dev, "No clock for device\n");
 424                 err = PTR_ERR(hw->clk);
 425                 goto err_clk;
 426         }
 427
 428         mfp_set_groupg(&pdev->dev, NULL);
 429         nuc900_init_spi(hw);
 430
 431         err = spi_bitbang_start(&hw->bitbang);
 432         if (err) {
 433                 dev_err(&pdev->dev, "Failed to register SPI master\n");
 434                 goto err_register;
 435         }
 436
 437         return 0;
 438
 439 err_register:
 440         clk_disable(hw->clk);
 441         clk_put(hw->clk);
 442 err_clk:
 443         free_irq(hw->irq, hw);
 444 err_irq:
 445         iounmap(hw->regs);
 446 err_iomap:
 447         release_mem_region(hw->res->start, resource_size(hw->res));
 448         kfree(hw->ioarea);
 449 err_pdata:
 450         spi_master_put(hw->master);
 451
 452 err_nomem:
 453         return err;
 454 }
 455
 456 static int nuc900_spi_remove(struct platform_device *dev)
 457 {
 458         struct nuc900_spi *hw = platform_get_drvdata(dev);
 459
 460         free_irq(hw->irq, hw);
 461
 462         platform_set_drvdata(dev, NULL);
 463
 464         spi_bitbang_stop(&hw->bitbang);
 465
 466         clk_disable(hw->clk);
 467         clk_put(hw->clk);
 468
 469         iounmap(hw->regs);
 470
 471         release_mem_region(hw->res->start, resource_size(hw->res));
 472         kfree(hw->ioarea);
 473
 474         spi_master_put(hw->master);
 475         return 0;
 476 }
 477
 478 static struct platform_driver nuc900_spi_driver = {
 479         .probe          = nuc900_spi_probe,
 480         .remove         = nuc900_spi_remove,
 481         .driver         = {
 482                 .name   = "nuc900-spi",
 483                 .owner  = THIS_MODULE,
 484         },
 485 };
 486 module_platform_driver(nuc900_spi_driver);
 487
 488 MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
 489 MODULE_DESCRIPTION("nuc900 spi driver!");
 490 MODULE_LICENSE("GPL");
 491 MODULE_ALIAS("platform:nuc900-spi");