drivers/mfd/ti-ssp.c

   1 /*
   2  * Sequencer Serial Port (SSP) driver for Texas Instruments' SoCs
   3  *
   4  * Copyright (C) 2010 Texas Instruments Inc
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <linux/errno.h>
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/slab.h>
  25 #include <linux/err.h>
  26 #include <linux/init.h>
  27 #include <linux/wait.h>
  28 #include <linux/clk.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/device.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/delay.h>
  34 #include <linux/io.h>
  35 #include <linux/mfd/core.h>
  36 #include <linux/mfd/ti_ssp.h>
  37
  38 /* Register Offsets */
  39 #define REG_REV         0x00
  40 #define REG_IOSEL_1     0x04
  41 #define REG_IOSEL_2     0x08
  42 #define REG_PREDIV      0x0c
  43 #define REG_INTR_ST     0x10
  44 #define REG_INTR_EN     0x14
  45 #define REG_TEST_CTRL   0x18
  46
  47 /* Per port registers */
  48 #define PORT_CFG_2      0x00
  49 #define PORT_ADDR       0x04
  50 #define PORT_DATA       0x08
  51 #define PORT_CFG_1      0x0c
  52 #define PORT_STATE      0x10
  53
  54 #define SSP_PORT_CONFIG_MASK    (SSP_EARLY_DIN | SSP_DELAY_DOUT)
  55 #define SSP_PORT_CLKRATE_MASK   0x0f
  56
  57 #define SSP_SEQRAM_WR_EN        BIT(4)
  58 #define SSP_SEQRAM_RD_EN        BIT(5)
  59 #define SSP_START               BIT(15)
  60 #define SSP_BUSY                BIT(10)
  61 #define SSP_PORT_ASL            BIT(7)
  62 #define SSP_PORT_CFO1           BIT(6)
  63
  64 #define SSP_PORT_SEQRAM_SIZE    32
  65
  66 static const int ssp_port_base[]   = {0x040, 0x080};
  67 static const int ssp_port_seqram[] = {0x100, 0x180};
  68
  69 struct ti_ssp {
  70         struct resource         *res;
  71         struct device           *dev;
  72         void __iomem            *regs;
  73         spinlock_t              lock;
  74         struct clk              *clk;
  75         int                     irq;
  76         wait_queue_head_t       wqh;
  77
  78         /*
  79          * Some of the iosel2 register bits always read-back as 0, we need to
  80          * remember these values so that we don't clobber previously set
  81          * values.
  82          */
  83         u32                     iosel2;
  84 };
  85
  86 static inline struct ti_ssp *dev_to_ssp(struct device *dev)
  87 {
  88         return dev_get_drvdata(dev->parent);
  89 }
  90
  91 static inline int dev_to_port(struct device *dev)
  92 {
  93         return to_platform_device(dev)->id;
  94 }
  95
  96 /* Register Access Helpers, rmw() functions need to run locked */
  97 static inline u32 ssp_read(struct ti_ssp *ssp, int reg)
  98 {
  99         return __raw_readl(ssp->regs + reg);
 100 }
 101
 102 static inline void ssp_write(struct ti_ssp *ssp, int reg, u32 val)
 103 {
 104         __raw_writel(val, ssp->regs + reg);
 105 }
 106
 107 static inline void ssp_rmw(struct ti_ssp *ssp, int reg, u32 mask, u32 bits)
 108 {
 109         ssp_write(ssp, reg, (ssp_read(ssp, reg) & ~mask) | bits);
 110 }
 111
 112 static inline u32 ssp_port_read(struct ti_ssp *ssp, int port, int reg)
 113 {
 114         return ssp_read(ssp, ssp_port_base[port] + reg);
 115 }
 116
 117 static inline void ssp_port_write(struct ti_ssp *ssp, int port, int reg,
 118                                   u32 val)
 119 {
 120         ssp_write(ssp, ssp_port_base[port] + reg, val);
 121 }
 122
 123 static inline void ssp_port_rmw(struct ti_ssp *ssp, int port, int reg,
 124                                 u32 mask, u32 bits)
 125 {
 126         ssp_rmw(ssp, ssp_port_base[port] + reg, mask, bits);
 127 }
 128
 129 static inline void ssp_port_clr_bits(struct ti_ssp *ssp, int port, int reg,
 130                                      u32 bits)
 131 {
 132         ssp_port_rmw(ssp, port, reg, bits, 0);
 133 }
 134
 135 static inline void ssp_port_set_bits(struct ti_ssp *ssp, int port, int reg,
 136                                      u32 bits)
 137 {
 138         ssp_port_rmw(ssp, port, reg, 0, bits);
 139 }
 140
 141 /* Called to setup port clock mode, caller must hold ssp->lock */
 142 static int __set_mode(struct ti_ssp *ssp, int port, int mode)
 143 {
 144         mode &= SSP_PORT_CONFIG_MASK;
 145         ssp_port_rmw(ssp, port, PORT_CFG_1, SSP_PORT_CONFIG_MASK, mode);
 146
 147         return 0;
 148 }
 149
 150 int ti_ssp_set_mode(struct device *dev, int mode)
 151 {
 152         struct ti_ssp *ssp = dev_to_ssp(dev);
 153         int port = dev_to_port(dev);
 154         int ret;
 155
 156         spin_lock(&ssp->lock);
 157         ret = __set_mode(ssp, port, mode);
 158         spin_unlock(&ssp->lock);
 159
 160         return ret;
 161 }
 162 EXPORT_SYMBOL(ti_ssp_set_mode);
 163
 164 /* Called to setup iosel2, caller must hold ssp->lock */
 165 static void __set_iosel2(struct ti_ssp *ssp, u32 mask, u32 val)
 166 {
 167         ssp->iosel2 = (ssp->iosel2 & ~mask) | val;
 168         ssp_write(ssp, REG_IOSEL_2, ssp->iosel2);
 169 }
 170
 171 /* Called to setup port iosel, caller must hold ssp->lock */
 172 static void __set_iosel(struct ti_ssp *ssp, int port, u32 iosel)
 173 {
 174         unsigned val, shift = port ? 16 : 0;
 175
 176         /* IOSEL1 gets the least significant 16 bits */
 177         val = ssp_read(ssp, REG_IOSEL_1);
 178         val &= 0xffff << (port ? 0 : 16);
 179         val |= (iosel & 0xffff) << (port ? 16 : 0);
 180         ssp_write(ssp, REG_IOSEL_1, val);
 181
 182         /* IOSEL2 gets the most significant 16 bits */
 183         val = (iosel >> 16) & 0x7;
 184         __set_iosel2(ssp, 0x7 << shift, val << shift);
 185 }
 186
 187 int ti_ssp_set_iosel(struct device *dev, u32 iosel)
 188 {
 189         struct ti_ssp *ssp = dev_to_ssp(dev);
 190         int port = dev_to_port(dev);
 191
 192         spin_lock(&ssp->lock);
 193         __set_iosel(ssp, port, iosel);
 194         spin_unlock(&ssp->lock);
 195
 196         return 0;
 197 }
 198 EXPORT_SYMBOL(ti_ssp_set_iosel);
 199
 200 int ti_ssp_load(struct device *dev, int offs, u32* prog, int len)
 201 {
 202         struct ti_ssp *ssp = dev_to_ssp(dev);
 203         int port = dev_to_port(dev);
 204         int i;
 205
 206         if (len > SSP_PORT_SEQRAM_SIZE)
 207                 return -ENOSPC;
 208
 209         spin_lock(&ssp->lock);
 210
 211         /* Enable SeqRAM access */
 212         ssp_port_set_bits(ssp, port, PORT_CFG_2, SSP_SEQRAM_WR_EN);
 213
 214         /* Copy code */
 215         for (i = 0; i < len; i++) {
 216                 __raw_writel(prog[i], ssp->regs + offs + 4*i +
 217                              ssp_port_seqram[port]);
 218         }
 219
 220         /* Disable SeqRAM access */
 221         ssp_port_clr_bits(ssp, port, PORT_CFG_2, SSP_SEQRAM_WR_EN);
 222
 223         spin_unlock(&ssp->lock);
 224
 225         return 0;
 226 }
 227 EXPORT_SYMBOL(ti_ssp_load);
 228
 229 int ti_ssp_raw_read(struct device *dev)
 230 {
 231         struct ti_ssp *ssp = dev_to_ssp(dev);
 232         int port = dev_to_port(dev);
 233         int shift = port ? 27 : 11;
 234
 235         return (ssp_read(ssp, REG_IOSEL_2) >> shift) & 0xf;
 236 }
 237 EXPORT_SYMBOL(ti_ssp_raw_read);
 238
 239 int ti_ssp_raw_write(struct device *dev, u32 val)
 240 {
 241         struct ti_ssp *ssp = dev_to_ssp(dev);
 242         int port = dev_to_port(dev), shift;
 243
 244         spin_lock(&ssp->lock);
 245
 246         shift = port ? 22 : 6;
 247         val &= 0xf;
 248         __set_iosel2(ssp, 0xf << shift, val << shift);
 249
 250         spin_unlock(&ssp->lock);
 251
 252         return 0;
 253 }
 254 EXPORT_SYMBOL(ti_ssp_raw_write);
 255
 256 static inline int __xfer_done(struct ti_ssp *ssp, int port)
 257 {
 258         return !(ssp_port_read(ssp, port, PORT_CFG_1) & SSP_BUSY);
 259 }
 260
 261 int ti_ssp_run(struct device *dev, u32 pc, u32 input, u32 *output)
 262 {
 263         struct ti_ssp *ssp = dev_to_ssp(dev);
 264         int port = dev_to_port(dev);
 265         int ret;
 266
 267         if (pc & ~(0x3f))
 268                 return -EINVAL;
 269
 270         /* Grab ssp->lock to serialize rmw on ssp registers */
 271         spin_lock(&ssp->lock);
 272
 273         ssp_port_write(ssp, port, PORT_ADDR, input >> 16);
 274         ssp_port_write(ssp, port, PORT_DATA, input & 0xffff);
 275         ssp_port_rmw(ssp, port, PORT_CFG_1, 0x3f, pc);
 276
 277         /* grab wait queue head lock to avoid race with the isr */
 278         spin_lock_irq(&ssp->wqh.lock);
 279
 280         /* kick off sequence execution in hardware */
 281         ssp_port_set_bits(ssp, port, PORT_CFG_1, SSP_START);
 282
 283         /* drop ssp lock; no register writes beyond this */
 284         spin_unlock(&ssp->lock);
 285
 286         ret = wait_event_interruptible_locked_irq(ssp->wqh,
 287                                                   __xfer_done(ssp, port));
 288         spin_unlock_irq(&ssp->wqh.lock);
 289
 290         if (ret < 0)
 291                 return ret;
 292
 293         if (output) {
 294                 *output = (ssp_port_read(ssp, port, PORT_ADDR) << 16) |
 295                           (ssp_port_read(ssp, port, PORT_DATA) &  0xffff);
 296         }
 297
 298         ret = ssp_port_read(ssp, port, PORT_STATE) & 0x3f; /* stop address */
 299
 300         return ret;
 301 }
 302 EXPORT_SYMBOL(ti_ssp_run);
 303
 304 static irqreturn_t ti_ssp_interrupt(int irq, void *dev_data)
 305 {
 306         struct ti_ssp *ssp = dev_data;
 307
 308         spin_lock(&ssp->wqh.lock);
 309
 310         ssp_write(ssp, REG_INTR_ST, 0x3);
 311         wake_up_locked(&ssp->wqh);
 312
 313         spin_unlock(&ssp->wqh.lock);
 314
 315         return IRQ_HANDLED;
 316 }
 317
 318 static int ti_ssp_probe(struct platform_device *pdev)
 319 {
 320         static struct ti_ssp *ssp;
 321         const struct ti_ssp_data *pdata = dev_get_platdata(&pdev->dev);
 322         int error = 0, prediv = 0xff, id;
 323         unsigned long sysclk;
 324         struct device *dev = &pdev->dev;
 325         struct mfd_cell cells[2];
 326
 327         ssp = kzalloc(sizeof(*ssp), GFP_KERNEL);
 328         if (!ssp) {
 329                 dev_err(dev, "cannot allocate device info\n");
 330                 return -ENOMEM;
 331         }
 332
 333         ssp->dev = dev;
 334         dev_set_drvdata(dev, ssp);
 335
 336         ssp->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 337         if (!ssp->res) {
 338                 error = -ENODEV;
 339                 dev_err(dev, "cannot determine register area\n");
 340                 goto error_res;
 341         }
 342
 343         if (!request_mem_region(ssp->res->start, resource_size(ssp->res),
 344                                 pdev->name)) {
 345                 error = -ENOMEM;
 346                 dev_err(dev, "cannot claim register memory\n");
 347                 goto error_res;
 348         }
 349
 350         ssp->regs = ioremap(ssp->res->start, resource_size(ssp->res));
 351         if (!ssp->regs) {
 352                 error = -ENOMEM;
 353                 dev_err(dev, "cannot map register memory\n");
 354                 goto error_map;
 355         }
 356
 357         ssp->clk = clk_get(dev, NULL);
 358         if (IS_ERR(ssp->clk)) {
 359                 error = PTR_ERR(ssp->clk);
 360                 dev_err(dev, "cannot claim device clock\n");
 361                 goto error_clk;
 362         }
 363
 364         ssp->irq = platform_get_irq(pdev, 0);
 365         if (ssp->irq < 0) {
 366                 error = -ENODEV;
 367                 dev_err(dev, "unknown irq\n");
 368                 goto error_irq;
 369         }
 370
 371         error = request_threaded_irq(ssp->irq, NULL, ti_ssp_interrupt, 0,
 372                                      dev_name(dev), ssp);
 373         if (error < 0) {
 374                 dev_err(dev, "cannot acquire irq\n");
 375                 goto error_irq;
 376         }
 377
 378         spin_lock_init(&ssp->lock);
 379         init_waitqueue_head(&ssp->wqh);
 380
 381         /* Power on and initialize SSP */
 382         error = clk_enable(ssp->clk);
 383         if (error) {
 384                 dev_err(dev, "cannot enable device clock\n");
 385                 goto error_enable;
 386         }
 387
 388         /* Reset registers to a sensible known state */
 389         ssp_write(ssp, REG_IOSEL_1, 0);
 390         ssp_write(ssp, REG_IOSEL_2, 0);
 391         ssp_write(ssp, REG_INTR_EN, 0x3);
 392         ssp_write(ssp, REG_INTR_ST, 0x3);
 393         ssp_write(ssp, REG_TEST_CTRL, 0);
 394         ssp_port_write(ssp, 0, PORT_CFG_1, SSP_PORT_ASL);
 395         ssp_port_write(ssp, 1, PORT_CFG_1, SSP_PORT_ASL);
 396         ssp_port_write(ssp, 0, PORT_CFG_2, SSP_PORT_CFO1);
 397         ssp_port_write(ssp, 1, PORT_CFG_2, SSP_PORT_CFO1);
 398
 399         sysclk = clk_get_rate(ssp->clk);
 400         if (pdata && pdata->out_clock)
 401                 prediv = (sysclk / pdata->out_clock) - 1;
 402         prediv = clamp(prediv, 0, 0xff);
 403         ssp_rmw(ssp, REG_PREDIV, 0xff, prediv);
 404
 405         memset(cells, 0, sizeof(cells));
 406         for (id = 0; id < 2; id++) {
 407                 const struct ti_ssp_dev_data *data = &pdata->dev_data[id];
 408
 409                 cells[id].id            = id;
 410                 cells[id].name          = data->dev_name;
 411                 cells[id].platform_data = data->pdata;
 412                 cells[id].data_size     = data->pdata_size;
 413         }
 414
 415         error = mfd_add_devices(dev, 0, cells, 2, NULL, 0, NULL);
 416         if (error < 0) {
 417                 dev_err(dev, "cannot add mfd cells\n");
 418                 goto error_enable;
 419         }
 420
 421         return 0;
 422
 423 error_enable:
 424         free_irq(ssp->irq, ssp);
 425 error_irq:
 426         clk_put(ssp->clk);
 427 error_clk:
 428         iounmap(ssp->regs);
 429 error_map:
 430         release_mem_region(ssp->res->start, resource_size(ssp->res));
 431 error_res:
 432         kfree(ssp);
 433         return error;
 434 }
 435
 436 static int ti_ssp_remove(struct platform_device *pdev)
 437 {
 438         struct device *dev = &pdev->dev;
 439         struct ti_ssp *ssp = dev_get_drvdata(dev);
 440
 441         mfd_remove_devices(dev);
 442         clk_disable(ssp->clk);
 443         free_irq(ssp->irq, ssp);
 444         clk_put(ssp->clk);
 445         iounmap(ssp->regs);
 446         release_mem_region(ssp->res->start, resource_size(ssp->res));
 447         kfree(ssp);
 448         dev_set_drvdata(dev, NULL);
 449         return 0;
 450 }
 451
 452 static struct platform_driver ti_ssp_driver = {
 453         .probe          = ti_ssp_probe,
 454         .remove         = ti_ssp_remove,
 455         .driver         = {
 456                 .name   = "ti-ssp",
 457                 .owner  = THIS_MODULE,
 458         }
 459 };
 460
 461 module_platform_driver(ti_ssp_driver);
 462
 463 MODULE_DESCRIPTION("Sequencer Serial Port (SSP) Driver");
 464 MODULE_AUTHOR("Cyril Chemparathy");
 465 MODULE_LICENSE("GPL");
 466 MODULE_ALIAS("platform:ti-ssp");