drivers/spi/spi-nuc900.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2009 Nuvoton technology.
   4  * Wan ZongShun <mcuos.com@gmail.com>
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/spinlock.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/delay.h>
  11 #include <linux/errno.h>
  12 #include <linux/err.h>
  13 #include <linux/clk.h>
  14 #include <linux/device.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/gpio.h>
  17 #include <linux/io.h>
  18 #include <linux/slab.h>
  19
  20 #include <linux/spi/spi.h>
  21 #include <linux/spi/spi_bitbang.h>
  22
  23 #include <linux/platform_data/spi-nuc900.h>
  24
  25 /* usi registers offset */
  26 #define USI_CNT         0x00
  27 #define USI_DIV         0x04
  28 #define USI_SSR         0x08
  29 #define USI_RX0         0x10
  30 #define USI_TX0         0x10
  31
  32 /* usi register bit */
  33 #define ENINT           (0x01 << 17)
  34 #define ENFLG           (0x01 << 16)
  35 #define SLEEP           (0x0f << 12)
  36 #define TXNUM           (0x03 << 8)
  37 #define TXBITLEN        (0x1f << 3)
  38 #define TXNEG           (0x01 << 2)
  39 #define RXNEG           (0x01 << 1)
  40 #define LSB             (0x01 << 10)
  41 #define SELECTLEV       (0x01 << 2)
  42 #define SELECTPOL       (0x01 << 31)
  43 #define SELECTSLAVE     0x01
  44 #define GOBUSY          0x01
  45
  46 struct nuc900_spi {
  47         struct spi_bitbang       bitbang;
  48         struct completion        done;
  49         void __iomem            *regs;
  50         int                      irq;
  51         int                      len;
  52         int                      count;
  53         const unsigned char     *tx;
  54         unsigned char           *rx;
  55         struct clk              *clk;
  56         struct spi_master       *master;
  57         struct nuc900_spi_info *pdata;
  58         spinlock_t              lock;
  59 };
  60
  61 static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
  62 {
  63         return spi_master_get_devdata(sdev->master);
  64 }
  65
  66 static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
  67 {
  68         struct nuc900_spi *hw = to_hw(spi);
  69         unsigned int val;
  70         unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
  71         unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
  72         unsigned long flags;
  73
  74         spin_lock_irqsave(&hw->lock, flags);
  75
  76         val = __raw_readl(hw->regs + USI_SSR);
  77
  78         if (!cs)
  79                 val &= ~SELECTLEV;
  80         else
  81                 val |= SELECTLEV;
  82
  83         if (!ssr)
  84                 val &= ~SELECTSLAVE;
  85         else
  86                 val |= SELECTSLAVE;
  87
  88         __raw_writel(val, hw->regs + USI_SSR);
  89
  90         val = __raw_readl(hw->regs + USI_CNT);
  91
  92         if (!cpol)
  93                 val &= ~SELECTPOL;
  94         else
  95                 val |= SELECTPOL;
  96
  97         __raw_writel(val, hw->regs + USI_CNT);
  98
  99         spin_unlock_irqrestore(&hw->lock, flags);
 100 }
 101
 102 static void nuc900_spi_chipsel(struct spi_device *spi, int value)
 103 {
 104         switch (value) {
 105         case BITBANG_CS_INACTIVE:
 106                 nuc900_slave_select(spi, 0);
 107                 break;
 108
 109         case BITBANG_CS_ACTIVE:
 110                 nuc900_slave_select(spi, 1);
 111                 break;
 112         }
 113 }
 114
 115 static void nuc900_spi_setup_txnum(struct nuc900_spi *hw, unsigned int txnum)
 116 {
 117         unsigned int val;
 118         unsigned long flags;
 119
 120         spin_lock_irqsave(&hw->lock, flags);
 121
 122         val = __raw_readl(hw->regs + USI_CNT) & ~TXNUM;
 123
 124         if (txnum)
 125                 val |= txnum << 0x08;
 126
 127         __raw_writel(val, hw->regs + USI_CNT);
 128
 129         spin_unlock_irqrestore(&hw->lock, flags);
 130
 131 }
 132
 133 static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
 134                                                         unsigned int txbitlen)
 135 {
 136         unsigned int val;
 137         unsigned long flags;
 138
 139         spin_lock_irqsave(&hw->lock, flags);
 140
 141         val = __raw_readl(hw->regs + USI_CNT) & ~TXBITLEN;
 142
 143         val |= (txbitlen << 0x03);
 144
 145         __raw_writel(val, hw->regs + USI_CNT);
 146
 147         spin_unlock_irqrestore(&hw->lock, flags);
 148 }
 149
 150 static void nuc900_spi_gobusy(struct nuc900_spi *hw)
 151 {
 152         unsigned int val;
 153         unsigned long flags;
 154
 155         spin_lock_irqsave(&hw->lock, flags);
 156
 157         val = __raw_readl(hw->regs + USI_CNT);
 158
 159         val |= GOBUSY;
 160
 161         __raw_writel(val, hw->regs + USI_CNT);
 162
 163         spin_unlock_irqrestore(&hw->lock, flags);
 164 }
 165
 166 static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
 167 {
 168         return hw->tx ? hw->tx[count] : 0;
 169 }
 170
 171 static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
 172 {
 173         struct nuc900_spi *hw = to_hw(spi);
 174
 175         hw->tx = t->tx_buf;
 176         hw->rx = t->rx_buf;
 177         hw->len = t->len;
 178         hw->count = 0;
 179
 180         __raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);
 181
 182         nuc900_spi_gobusy(hw);
 183
 184         wait_for_completion(&hw->done);
 185
 186         return hw->count;
 187 }
 188
 189 static irqreturn_t nuc900_spi_irq(int irq, void *dev)
 190 {
 191         struct nuc900_spi *hw = dev;
 192         unsigned int status;
 193         unsigned int count = hw->count;
 194
 195         status = __raw_readl(hw->regs + USI_CNT);
 196         __raw_writel(status, hw->regs + USI_CNT);
 197
 198         if (status & ENFLG) {
 199                 hw->count++;
 200
 201                 if (hw->rx)
 202                         hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
 203                 count++;
 204
 205                 if (count < hw->len) {
 206                         __raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
 207                         nuc900_spi_gobusy(hw);
 208                 } else {
 209                         complete(&hw->done);
 210                 }
 211
 212                 return IRQ_HANDLED;
 213         }
 214
 215         complete(&hw->done);
 216         return IRQ_HANDLED;
 217 }
 218
 219 static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
 220 {
 221         unsigned int val;
 222         unsigned long flags;
 223
 224         spin_lock_irqsave(&hw->lock, flags);
 225
 226         val = __raw_readl(hw->regs + USI_CNT);
 227
 228         if (edge)
 229                 val |= TXNEG;
 230         else
 231                 val &= ~TXNEG;
 232         __raw_writel(val, hw->regs + USI_CNT);
 233
 234         spin_unlock_irqrestore(&hw->lock, flags);
 235 }
 236
 237 static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
 238 {
 239         unsigned int val;
 240         unsigned long flags;
 241
 242         spin_lock_irqsave(&hw->lock, flags);
 243
 244         val = __raw_readl(hw->regs + USI_CNT);
 245
 246         if (edge)
 247                 val |= RXNEG;
 248         else
 249                 val &= ~RXNEG;
 250         __raw_writel(val, hw->regs + USI_CNT);
 251
 252         spin_unlock_irqrestore(&hw->lock, flags);
 253 }
 254
 255 static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
 256 {
 257         unsigned int val;
 258         unsigned long flags;
 259
 260         spin_lock_irqsave(&hw->lock, flags);
 261
 262         val = __raw_readl(hw->regs + USI_CNT);
 263
 264         if (lsb)
 265                 val |= LSB;
 266         else
 267                 val &= ~LSB;
 268         __raw_writel(val, hw->regs + USI_CNT);
 269
 270         spin_unlock_irqrestore(&hw->lock, flags);
 271 }
 272
 273 static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
 274 {
 275         unsigned int val;
 276         unsigned long flags;
 277
 278         spin_lock_irqsave(&hw->lock, flags);
 279
 280         val = __raw_readl(hw->regs + USI_CNT) & ~SLEEP;
 281
 282         if (sleep)
 283                 val |= (sleep << 12);
 284
 285         __raw_writel(val, hw->regs + USI_CNT);
 286
 287         spin_unlock_irqrestore(&hw->lock, flags);
 288 }
 289
 290 static void nuc900_enable_int(struct nuc900_spi *hw)
 291 {
 292         unsigned int val;
 293         unsigned long flags;
 294
 295         spin_lock_irqsave(&hw->lock, flags);
 296
 297         val = __raw_readl(hw->regs + USI_CNT);
 298
 299         val |= ENINT;
 300
 301         __raw_writel(val, hw->regs + USI_CNT);
 302
 303         spin_unlock_irqrestore(&hw->lock, flags);
 304 }
 305
 306 static void nuc900_set_divider(struct nuc900_spi *hw)
 307 {
 308         __raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
 309 }
 310
 311 static void nuc900_init_spi(struct nuc900_spi *hw)
 312 {
 313         clk_enable(hw->clk);
 314         spin_lock_init(&hw->lock);
 315
 316         nuc900_tx_edge(hw, hw->pdata->txneg);
 317         nuc900_rx_edge(hw, hw->pdata->rxneg);
 318         nuc900_send_first(hw, hw->pdata->lsb);
 319         nuc900_set_sleep(hw, hw->pdata->sleep);
 320         nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
 321         nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
 322         nuc900_set_divider(hw);
 323         nuc900_enable_int(hw);
 324 }
 325
 326 static int nuc900_spi_probe(struct platform_device *pdev)
 327 {
 328         struct nuc900_spi *hw;
 329         struct spi_master *master;
 330         struct resource *res;
 331         int err = 0;
 332
 333         master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
 334         if (master == NULL) {
 335                 dev_err(&pdev->dev, "No memory for spi_master\n");
 336                 return -ENOMEM;
 337         }
 338
 339         hw = spi_master_get_devdata(master);
 340         hw->master = master;
 341         hw->pdata  = dev_get_platdata(&pdev->dev);
 342
 343         if (hw->pdata == NULL) {
 344                 dev_err(&pdev->dev, "No platform data supplied\n");
 345                 err = -ENOENT;
 346                 goto err_pdata;
 347         }
 348
 349         platform_set_drvdata(pdev, hw);
 350         init_completion(&hw->done);
 351
 352         master->mode_bits          = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 353         if (hw->pdata->lsb)
 354                 master->mode_bits |= SPI_LSB_FIRST;
 355         master->num_chipselect     = hw->pdata->num_cs;
 356         master->bus_num            = hw->pdata->bus_num;
 357         hw->bitbang.master         = hw->master;
 358         hw->bitbang.chipselect     = nuc900_spi_chipsel;
 359         hw->bitbang.txrx_bufs      = nuc900_spi_txrx;
 360
 361         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 362         hw->regs = devm_ioremap_resource(&pdev->dev, res);
 363         if (IS_ERR(hw->regs)) {
 364                 err = PTR_ERR(hw->regs);
 365                 goto err_pdata;
 366         }
 367
 368         hw->irq = platform_get_irq(pdev, 0);
 369         if (hw->irq < 0) {
 370                 dev_err(&pdev->dev, "No IRQ specified\n");
 371                 err = -ENOENT;
 372                 goto err_pdata;
 373         }
 374
 375         err = devm_request_irq(&pdev->dev, hw->irq, nuc900_spi_irq, 0,
 376                                 pdev->name, hw);
 377         if (err) {
 378                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
 379                 goto err_pdata;
 380         }
 381
 382         hw->clk = devm_clk_get(&pdev->dev, "spi");
 383         if (IS_ERR(hw->clk)) {
 384                 dev_err(&pdev->dev, "No clock for device\n");
 385                 err = PTR_ERR(hw->clk);
 386                 goto err_pdata;
 387         }
 388
 389         mfp_set_groupg(&pdev->dev, NULL);
 390         nuc900_init_spi(hw);
 391
 392         err = spi_bitbang_start(&hw->bitbang);
 393         if (err) {
 394                 dev_err(&pdev->dev, "Failed to register SPI master\n");
 395                 goto err_register;
 396         }
 397
 398         return 0;
 399
 400 err_register:
 401         clk_disable(hw->clk);
 402 err_pdata:
 403         spi_master_put(hw->master);
 404         return err;
 405 }
 406
 407 static int nuc900_spi_remove(struct platform_device *dev)
 408 {
 409         struct nuc900_spi *hw = platform_get_drvdata(dev);
 410
 411         spi_bitbang_stop(&hw->bitbang);
 412         clk_disable(hw->clk);
 413         spi_master_put(hw->master);
 414         return 0;
 415 }
 416
 417 static struct platform_driver nuc900_spi_driver = {
 418         .probe          = nuc900_spi_probe,
 419         .remove         = nuc900_spi_remove,
 420         .driver         = {
 421                 .name   = "nuc900-spi",
 422         },
 423 };
 424 module_platform_driver(nuc900_spi_driver);
 425
 426 MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
 427 MODULE_DESCRIPTION("nuc900 spi driver!");
 428 MODULE_LICENSE("GPL");
 429 MODULE_ALIAS("platform:nuc900-spi");