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/spinlock.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/delay.h>
  15 #include <linux/errno.h>
  16 #include <linux/err.h>
  17 #include <linux/clk.h>
  18 #include <linux/device.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/gpio.h>
  21 #include <linux/io.h>
  22 #include <linux/slab.h>
  23
  24 #include <linux/spi/spi.h>
  25 #include <linux/spi/spi_bitbang.h>
  26
  27 #include <linux/platform_data/spi-nuc900.h>
  28
  29 /* usi registers offset */
  30 #define USI_CNT         0x00
  31 #define USI_DIV         0x04
  32 #define USI_SSR         0x08
  33 #define USI_RX0         0x10
  34 #define USI_TX0         0x10
  35
  36 /* usi register bit */
  37 #define ENINT           (0x01 << 17)
  38 #define ENFLG           (0x01 << 16)
  39 #define SLEEP           (0x0f << 12)
  40 #define TXNUM           (0x03 << 8)
  41 #define TXBITLEN        (0x1f << 3)
  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 spi_master       *master;
  61         struct nuc900_spi_info *pdata;
  62         spinlock_t              lock;
  63 };
  64
  65 static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
  66 {
  67         return spi_master_get_devdata(sdev->master);
  68 }
  69
  70 static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
  71 {
  72         struct nuc900_spi *hw = to_hw(spi);
  73         unsigned int val;
  74         unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
  75         unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
  76         unsigned long flags;
  77
  78         spin_lock_irqsave(&hw->lock, flags);
  79
  80         val = __raw_readl(hw->regs + USI_SSR);
  81
  82         if (!cs)
  83                 val &= ~SELECTLEV;
  84         else
  85                 val |= SELECTLEV;
  86
  87         if (!ssr)
  88                 val &= ~SELECTSLAVE;
  89         else
  90                 val |= SELECTSLAVE;
  91
  92         __raw_writel(val, hw->regs + USI_SSR);
  93
  94         val = __raw_readl(hw->regs + USI_CNT);
  95
  96         if (!cpol)
  97                 val &= ~SELECTPOL;
  98         else
  99                 val |= SELECTPOL;
 100
 101         __raw_writel(val, hw->regs + USI_CNT);
 102
 103         spin_unlock_irqrestore(&hw->lock, flags);
 104 }
 105
 106 static void nuc900_spi_chipsel(struct spi_device *spi, int value)
 107 {
 108         switch (value) {
 109         case BITBANG_CS_INACTIVE:
 110                 nuc900_slave_select(spi, 0);
 111                 break;
 112
 113         case BITBANG_CS_ACTIVE:
 114                 nuc900_slave_select(spi, 1);
 115                 break;
 116         }
 117 }
 118
 119 static void nuc900_spi_setup_txnum(struct nuc900_spi *hw, unsigned int txnum)
 120 {
 121         unsigned int val;
 122         unsigned long flags;
 123
 124         spin_lock_irqsave(&hw->lock, flags);
 125
 126         val = __raw_readl(hw->regs + USI_CNT) & ~TXNUM;
 127
 128         if (txnum)
 129                 val |= txnum << 0x08;
 130
 131         __raw_writel(val, hw->regs + USI_CNT);
 132
 133         spin_unlock_irqrestore(&hw->lock, flags);
 134
 135 }
 136
 137 static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
 138                                                         unsigned int txbitlen)
 139 {
 140         unsigned int val;
 141         unsigned long flags;
 142
 143         spin_lock_irqsave(&hw->lock, flags);
 144
 145         val = __raw_readl(hw->regs + USI_CNT) & ~TXBITLEN;
 146
 147         val |= (txbitlen << 0x03);
 148
 149         __raw_writel(val, hw->regs + USI_CNT);
 150
 151         spin_unlock_irqrestore(&hw->lock, flags);
 152 }
 153
 154 static void nuc900_spi_gobusy(struct nuc900_spi *hw)
 155 {
 156         unsigned int val;
 157         unsigned long flags;
 158
 159         spin_lock_irqsave(&hw->lock, flags);
 160
 161         val = __raw_readl(hw->regs + USI_CNT);
 162
 163         val |= GOBUSY;
 164
 165         __raw_writel(val, hw->regs + USI_CNT);
 166
 167         spin_unlock_irqrestore(&hw->lock, flags);
 168 }
 169
 170 static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
 171 {
 172         return hw->tx ? hw->tx[count] : 0;
 173 }
 174
 175 static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
 176 {
 177         struct nuc900_spi *hw = to_hw(spi);
 178
 179         hw->tx = t->tx_buf;
 180         hw->rx = t->rx_buf;
 181         hw->len = t->len;
 182         hw->count = 0;
 183
 184         __raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);
 185
 186         nuc900_spi_gobusy(hw);
 187
 188         wait_for_completion(&hw->done);
 189
 190         return hw->count;
 191 }
 192
 193 static irqreturn_t nuc900_spi_irq(int irq, void *dev)
 194 {
 195         struct nuc900_spi *hw = dev;
 196         unsigned int status;
 197         unsigned int count = hw->count;
 198
 199         status = __raw_readl(hw->regs + USI_CNT);
 200         __raw_writel(status, hw->regs + USI_CNT);
 201
 202         if (status & ENFLG) {
 203                 hw->count++;
 204
 205                 if (hw->rx)
 206                         hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
 207                 count++;
 208
 209                 if (count < hw->len) {
 210                         __raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
 211                         nuc900_spi_gobusy(hw);
 212                 } else {
 213                         complete(&hw->done);
 214                 }
 215
 216                 return IRQ_HANDLED;
 217         }
 218
 219         complete(&hw->done);
 220         return IRQ_HANDLED;
 221 }
 222
 223 static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
 224 {
 225         unsigned int val;
 226         unsigned long flags;
 227
 228         spin_lock_irqsave(&hw->lock, flags);
 229
 230         val = __raw_readl(hw->regs + USI_CNT);
 231
 232         if (edge)
 233                 val |= TXNEG;
 234         else
 235                 val &= ~TXNEG;
 236         __raw_writel(val, hw->regs + USI_CNT);
 237
 238         spin_unlock_irqrestore(&hw->lock, flags);
 239 }
 240
 241 static void nuc900_rx_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 |= RXNEG;
 252         else
 253                 val &= ~RXNEG;
 254         __raw_writel(val, hw->regs + USI_CNT);
 255
 256         spin_unlock_irqrestore(&hw->lock, flags);
 257 }
 258
 259 static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
 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 (lsb)
 269                 val |= LSB;
 270         else
 271                 val &= ~LSB;
 272         __raw_writel(val, hw->regs + USI_CNT);
 273
 274         spin_unlock_irqrestore(&hw->lock, flags);
 275 }
 276
 277 static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
 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) & ~SLEEP;
 285
 286         if (sleep)
 287                 val |= (sleep << 12);
 288
 289         __raw_writel(val, hw->regs + USI_CNT);
 290
 291         spin_unlock_irqrestore(&hw->lock, flags);
 292 }
 293
 294 static void nuc900_enable_int(struct nuc900_spi *hw)
 295 {
 296         unsigned int val;
 297         unsigned long flags;
 298
 299         spin_lock_irqsave(&hw->lock, flags);
 300
 301         val = __raw_readl(hw->regs + USI_CNT);
 302
 303         val |= ENINT;
 304
 305         __raw_writel(val, hw->regs + USI_CNT);
 306
 307         spin_unlock_irqrestore(&hw->lock, flags);
 308 }
 309
 310 static void nuc900_set_divider(struct nuc900_spi *hw)
 311 {
 312         __raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
 313 }
 314
 315 static void nuc900_init_spi(struct nuc900_spi *hw)
 316 {
 317         clk_enable(hw->clk);
 318         spin_lock_init(&hw->lock);
 319
 320         nuc900_tx_edge(hw, hw->pdata->txneg);
 321         nuc900_rx_edge(hw, hw->pdata->rxneg);
 322         nuc900_send_first(hw, hw->pdata->lsb);
 323         nuc900_set_sleep(hw, hw->pdata->sleep);
 324         nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
 325         nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
 326         nuc900_set_divider(hw);
 327         nuc900_enable_int(hw);
 328 }
 329
 330 static int nuc900_spi_probe(struct platform_device *pdev)
 331 {
 332         struct nuc900_spi *hw;
 333         struct spi_master *master;
 334         struct resource *res;
 335         int err = 0;
 336
 337         master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
 338         if (master == NULL) {
 339                 dev_err(&pdev->dev, "No memory for spi_master\n");
 340                 return -ENOMEM;
 341         }
 342
 343         hw = spi_master_get_devdata(master);
 344         hw->master = master;
 345         hw->pdata  = dev_get_platdata(&pdev->dev);
 346
 347         if (hw->pdata == NULL) {
 348                 dev_err(&pdev->dev, "No platform data supplied\n");
 349                 err = -ENOENT;
 350                 goto err_pdata;
 351         }
 352
 353         platform_set_drvdata(pdev, hw);
 354         init_completion(&hw->done);
 355
 356         master->mode_bits          = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 357         if (hw->pdata->lsb)
 358                 master->mode_bits |= SPI_LSB_FIRST;
 359         master->num_chipselect     = hw->pdata->num_cs;
 360         master->bus_num            = hw->pdata->bus_num;
 361         hw->bitbang.master         = hw->master;
 362         hw->bitbang.chipselect     = nuc900_spi_chipsel;
 363         hw->bitbang.txrx_bufs      = nuc900_spi_txrx;
 364
 365         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 366         hw->regs = devm_ioremap_resource(&pdev->dev, res);
 367         if (IS_ERR(hw->regs)) {
 368                 err = PTR_ERR(hw->regs);
 369                 goto err_pdata;
 370         }
 371
 372         hw->irq = platform_get_irq(pdev, 0);
 373         if (hw->irq < 0) {
 374                 dev_err(&pdev->dev, "No IRQ specified\n");
 375                 err = -ENOENT;
 376                 goto err_pdata;
 377         }
 378
 379         err = devm_request_irq(&pdev->dev, hw->irq, nuc900_spi_irq, 0,
 380                                 pdev->name, hw);
 381         if (err) {
 382                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
 383                 goto err_pdata;
 384         }
 385
 386         hw->clk = devm_clk_get(&pdev->dev, "spi");
 387         if (IS_ERR(hw->clk)) {
 388                 dev_err(&pdev->dev, "No clock for device\n");
 389                 err = PTR_ERR(hw->clk);
 390                 goto err_pdata;
 391         }
 392
 393         mfp_set_groupg(&pdev->dev, NULL);
 394         nuc900_init_spi(hw);
 395
 396         err = spi_bitbang_start(&hw->bitbang);
 397         if (err) {
 398                 dev_err(&pdev->dev, "Failed to register SPI master\n");
 399                 goto err_register;
 400         }
 401
 402         return 0;
 403
 404 err_register:
 405         clk_disable(hw->clk);
 406 err_pdata:
 407         spi_master_put(hw->master);
 408         return err;
 409 }
 410
 411 static int nuc900_spi_remove(struct platform_device *dev)
 412 {
 413         struct nuc900_spi *hw = platform_get_drvdata(dev);
 414
 415         spi_bitbang_stop(&hw->bitbang);
 416         clk_disable(hw->clk);
 417         spi_master_put(hw->master);
 418         return 0;
 419 }
 420
 421 static struct platform_driver nuc900_spi_driver = {
 422         .probe          = nuc900_spi_probe,
 423         .remove         = nuc900_spi_remove,
 424         .driver         = {
 425                 .name   = "nuc900-spi",
 426         },
 427 };
 428 module_platform_driver(nuc900_spi_driver);
 429
 430 MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
 431 MODULE_DESCRIPTION("nuc900 spi driver!");
 432 MODULE_LICENSE("GPL");
 433 MODULE_ALIAS("platform:nuc900-spi");