drivers/hsi/controllers/omap_ssi.c

   1 /* OMAP SSI driver.
   2  *
   3  * Copyright (C) 2010 Nokia Corporation. All rights reserved.
   4  * Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
   5  *
   6  * Contact: Carlos Chinea <carlos.chinea@nokia.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * version 2 as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  20  * 02110-1301 USA
  21  */
  22
  23 #include <linux/compiler.h>
  24 #include <linux/err.h>
  25 #include <linux/ioport.h>
  26 #include <linux/io.h>
  27 #include <linux/clk.h>
  28 #include <linux/device.h>
  29 #include <linux/platform_device.h>
  30 #include <linux/dma-mapping.h>
  31 #include <linux/dmaengine.h>
  32 #include <linux/delay.h>
  33 #include <linux/seq_file.h>
  34 #include <linux/scatterlist.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/debugfs.h>
  38 #include <linux/pm_runtime.h>
  39 #include <linux/of_platform.h>
  40 #include <linux/hsi/hsi.h>
  41 #include <linux/idr.h>
  42
  43 #include "omap_ssi_regs.h"
  44 #include "omap_ssi.h"
  45
  46 /* For automatically allocated device IDs */
  47 static DEFINE_IDA(platform_omap_ssi_ida);
  48
  49 #ifdef CONFIG_DEBUG_FS
  50 static int ssi_debug_show(struct seq_file *m, void *p __maybe_unused)
  51 {
  52         struct hsi_controller *ssi = m->private;
  53         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
  54         void __iomem *sys = omap_ssi->sys;
  55
  56         pm_runtime_get_sync(ssi->device.parent);
  57         seq_printf(m, "REVISION\t: 0x%08x\n",  readl(sys + SSI_REVISION_REG));
  58         seq_printf(m, "SYSCONFIG\t: 0x%08x\n", readl(sys + SSI_SYSCONFIG_REG));
  59         seq_printf(m, "SYSSTATUS\t: 0x%08x\n", readl(sys + SSI_SYSSTATUS_REG));
  60         pm_runtime_put_sync(ssi->device.parent);
  61
  62         return 0;
  63 }
  64
  65 static int ssi_debug_gdd_show(struct seq_file *m, void *p __maybe_unused)
  66 {
  67         struct hsi_controller *ssi = m->private;
  68         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
  69         void __iomem *gdd = omap_ssi->gdd;
  70         void __iomem *sys = omap_ssi->sys;
  71         int lch;
  72
  73         pm_runtime_get_sync(ssi->device.parent);
  74
  75         seq_printf(m, "GDD_MPU_STATUS\t: 0x%08x\n",
  76                 readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG));
  77         seq_printf(m, "GDD_MPU_ENABLE\t: 0x%08x\n\n",
  78                 readl(sys + SSI_GDD_MPU_IRQ_ENABLE_REG));
  79         seq_printf(m, "HW_ID\t\t: 0x%08x\n",
  80                                 readl(gdd + SSI_GDD_HW_ID_REG));
  81         seq_printf(m, "PPORT_ID\t: 0x%08x\n",
  82                                 readl(gdd + SSI_GDD_PPORT_ID_REG));
  83         seq_printf(m, "MPORT_ID\t: 0x%08x\n",
  84                                 readl(gdd + SSI_GDD_MPORT_ID_REG));
  85         seq_printf(m, "TEST\t\t: 0x%08x\n",
  86                                 readl(gdd + SSI_GDD_TEST_REG));
  87         seq_printf(m, "GCR\t\t: 0x%08x\n",
  88                                 readl(gdd + SSI_GDD_GCR_REG));
  89
  90         for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
  91                 seq_printf(m, "\nGDD LCH %d\n=========\n", lch);
  92                 seq_printf(m, "CSDP\t\t: 0x%04x\n",
  93                                 readw(gdd + SSI_GDD_CSDP_REG(lch)));
  94                 seq_printf(m, "CCR\t\t: 0x%04x\n",
  95                                 readw(gdd + SSI_GDD_CCR_REG(lch)));
  96                 seq_printf(m, "CICR\t\t: 0x%04x\n",
  97                                 readw(gdd + SSI_GDD_CICR_REG(lch)));
  98                 seq_printf(m, "CSR\t\t: 0x%04x\n",
  99                                 readw(gdd + SSI_GDD_CSR_REG(lch)));
 100                 seq_printf(m, "CSSA\t\t: 0x%08x\n",
 101                                 readl(gdd + SSI_GDD_CSSA_REG(lch)));
 102                 seq_printf(m, "CDSA\t\t: 0x%08x\n",
 103                                 readl(gdd + SSI_GDD_CDSA_REG(lch)));
 104                 seq_printf(m, "CEN\t\t: 0x%04x\n",
 105                                 readw(gdd + SSI_GDD_CEN_REG(lch)));
 106                 seq_printf(m, "CSAC\t\t: 0x%04x\n",
 107                                 readw(gdd + SSI_GDD_CSAC_REG(lch)));
 108                 seq_printf(m, "CDAC\t\t: 0x%04x\n",
 109                                 readw(gdd + SSI_GDD_CDAC_REG(lch)));
 110                 seq_printf(m, "CLNK_CTRL\t: 0x%04x\n",
 111                                 readw(gdd + SSI_GDD_CLNK_CTRL_REG(lch)));
 112         }
 113
 114         pm_runtime_put_sync(ssi->device.parent);
 115
 116         return 0;
 117 }
 118
 119 static int ssi_regs_open(struct inode *inode, struct file *file)
 120 {
 121         return single_open(file, ssi_debug_show, inode->i_private);
 122 }
 123
 124 static int ssi_gdd_regs_open(struct inode *inode, struct file *file)
 125 {
 126         return single_open(file, ssi_debug_gdd_show, inode->i_private);
 127 }
 128
 129 static const struct file_operations ssi_regs_fops = {
 130         .open           = ssi_regs_open,
 131         .read           = seq_read,
 132         .llseek         = seq_lseek,
 133         .release        = single_release,
 134 };
 135
 136 static const struct file_operations ssi_gdd_regs_fops = {
 137         .open           = ssi_gdd_regs_open,
 138         .read           = seq_read,
 139         .llseek         = seq_lseek,
 140         .release        = single_release,
 141 };
 142
 143 static int __init ssi_debug_add_ctrl(struct hsi_controller *ssi)
 144 {
 145         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 146         struct dentry *dir;
 147
 148         /* SSI controller */
 149         omap_ssi->dir = debugfs_create_dir(dev_name(&ssi->device), NULL);
 150         if (!omap_ssi->dir)
 151                 return -ENOMEM;
 152
 153         debugfs_create_file("regs", S_IRUGO, omap_ssi->dir, ssi,
 154                                                                 &ssi_regs_fops);
 155         /* SSI GDD (DMA) */
 156         dir = debugfs_create_dir("gdd", omap_ssi->dir);
 157         if (!dir)
 158                 goto rback;
 159         debugfs_create_file("regs", S_IRUGO, dir, ssi, &ssi_gdd_regs_fops);
 160
 161         return 0;
 162 rback:
 163         debugfs_remove_recursive(omap_ssi->dir);
 164
 165         return -ENOMEM;
 166 }
 167
 168 static void ssi_debug_remove_ctrl(struct hsi_controller *ssi)
 169 {
 170         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 171
 172         debugfs_remove_recursive(omap_ssi->dir);
 173 }
 174 #endif /* CONFIG_DEBUG_FS */
 175
 176 /*
 177  * FIXME: Horrible HACK needed until we remove the useless wakeline test
 178  * in the CMT. To be removed !!!!
 179  */
 180 void ssi_waketest(struct hsi_client *cl, unsigned int enable)
 181 {
 182         struct hsi_port *port = hsi_get_port(cl);
 183         struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
 184         struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
 185         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 186
 187         omap_port->wktest = !!enable;
 188         if (omap_port->wktest) {
 189                 pm_runtime_get_sync(ssi->device.parent);
 190                 writel_relaxed(SSI_WAKE(0),
 191                                 omap_ssi->sys + SSI_SET_WAKE_REG(port->num));
 192         } else {
 193                 writel_relaxed(SSI_WAKE(0),
 194                                 omap_ssi->sys + SSI_CLEAR_WAKE_REG(port->num));
 195                 pm_runtime_put_sync(ssi->device.parent);
 196         }
 197 }
 198 EXPORT_SYMBOL_GPL(ssi_waketest);
 199
 200 static void ssi_gdd_complete(struct hsi_controller *ssi, unsigned int lch)
 201 {
 202         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 203         struct hsi_msg *msg = omap_ssi->gdd_trn[lch].msg;
 204         struct hsi_port *port = to_hsi_port(msg->cl->device.parent);
 205         struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
 206         unsigned int dir;
 207         u32 csr;
 208         u32 val;
 209
 210         spin_lock(&omap_ssi->lock);
 211
 212         val = readl(omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
 213         val &= ~SSI_GDD_LCH(lch);
 214         writel_relaxed(val, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
 215
 216         if (msg->ttype == HSI_MSG_READ) {
 217                 dir = DMA_FROM_DEVICE;
 218                 val = SSI_DATAAVAILABLE(msg->channel);
 219                 pm_runtime_put_sync(ssi->device.parent);
 220         } else {
 221                 dir = DMA_TO_DEVICE;
 222                 val = SSI_DATAACCEPT(msg->channel);
 223                 /* Keep clocks reference for write pio event */
 224         }
 225         dma_unmap_sg(&ssi->device, msg->sgt.sgl, msg->sgt.nents, dir);
 226         csr = readw(omap_ssi->gdd + SSI_GDD_CSR_REG(lch));
 227         omap_ssi->gdd_trn[lch].msg = NULL; /* release GDD lch */
 228         dev_dbg(&port->device, "DMA completed ch %d ttype %d\n",
 229                                 msg->channel, msg->ttype);
 230         spin_unlock(&omap_ssi->lock);
 231         if (csr & SSI_CSR_TOUR) { /* Timeout error */
 232                 msg->status = HSI_STATUS_ERROR;
 233                 msg->actual_len = 0;
 234                 spin_lock(&omap_port->lock);
 235                 list_del(&msg->link); /* Dequeue msg */
 236                 spin_unlock(&omap_port->lock);
 237                 msg->complete(msg);
 238                 return;
 239         }
 240         spin_lock(&omap_port->lock);
 241         val |= readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
 242         writel_relaxed(val, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
 243         spin_unlock(&omap_port->lock);
 244
 245         msg->status = HSI_STATUS_COMPLETED;
 246         msg->actual_len = sg_dma_len(msg->sgt.sgl);
 247 }
 248
 249 static void ssi_gdd_tasklet(unsigned long dev)
 250 {
 251         struct hsi_controller *ssi = (struct hsi_controller *)dev;
 252         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 253         void __iomem *sys = omap_ssi->sys;
 254         unsigned int lch;
 255         u32 status_reg;
 256
 257         pm_runtime_get_sync(ssi->device.parent);
 258
 259         status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
 260         for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
 261                 if (status_reg & SSI_GDD_LCH(lch))
 262                         ssi_gdd_complete(ssi, lch);
 263         }
 264         writel_relaxed(status_reg, sys + SSI_GDD_MPU_IRQ_STATUS_REG);
 265         status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
 266
 267         pm_runtime_put_sync(ssi->device.parent);
 268
 269         if (status_reg)
 270                 tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
 271         else
 272                 enable_irq(omap_ssi->gdd_irq);
 273
 274 }
 275
 276 static irqreturn_t ssi_gdd_isr(int irq, void *ssi)
 277 {
 278         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 279
 280         tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
 281         disable_irq_nosync(irq);
 282
 283         return IRQ_HANDLED;
 284 }
 285
 286 static unsigned long ssi_get_clk_rate(struct hsi_controller *ssi)
 287 {
 288         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 289         unsigned long rate = clk_get_rate(omap_ssi->fck);
 290         return rate;
 291 }
 292
 293 static int __init ssi_get_iomem(struct platform_device *pd,
 294                 const char *name, void __iomem **pbase, dma_addr_t *phy)
 295 {
 296         struct resource *mem;
 297         void __iomem *base;
 298         struct hsi_controller *ssi = platform_get_drvdata(pd);
 299
 300         mem = platform_get_resource_byname(pd, IORESOURCE_MEM, name);
 301         base = devm_ioremap_resource(&ssi->device, mem);
 302         if (IS_ERR(base))
 303                 return PTR_ERR(base);
 304
 305         *pbase = base;
 306
 307         if (phy)
 308                 *phy = mem->start;
 309
 310         return 0;
 311 }
 312
 313 static int __init ssi_add_controller(struct hsi_controller *ssi,
 314                                                 struct platform_device *pd)
 315 {
 316         struct omap_ssi_controller *omap_ssi;
 317         int err;
 318
 319         omap_ssi = devm_kzalloc(&ssi->device, sizeof(*omap_ssi), GFP_KERNEL);
 320         if (!omap_ssi) {
 321                 dev_err(&pd->dev, "not enough memory for omap ssi\n");
 322                 return -ENOMEM;
 323         }
 324
 325         err = ida_simple_get(&platform_omap_ssi_ida, 0, 0, GFP_KERNEL);
 326         if (err < 0)
 327                 goto out_err;
 328         ssi->id = err;
 329
 330         ssi->owner = THIS_MODULE;
 331         ssi->device.parent = &pd->dev;
 332         dev_set_name(&ssi->device, "ssi%d", ssi->id);
 333         hsi_controller_set_drvdata(ssi, omap_ssi);
 334         omap_ssi->dev = &ssi->device;
 335         err = ssi_get_iomem(pd, "sys", &omap_ssi->sys, NULL);
 336         if (err < 0)
 337                 goto out_err;
 338         err = ssi_get_iomem(pd, "gdd", &omap_ssi->gdd, NULL);
 339         if (err < 0)
 340                 goto out_err;
 341         err = platform_get_irq_byname(pd, "gdd_mpu");
 342         if (err < 0) {
 343                 dev_err(&pd->dev, "GDD IRQ resource missing\n");
 344                 goto out_err;
 345         }
 346         omap_ssi->gdd_irq = err;
 347         tasklet_init(&omap_ssi->gdd_tasklet, ssi_gdd_tasklet,
 348                                                         (unsigned long)ssi);
 349         err = devm_request_irq(&ssi->device, omap_ssi->gdd_irq, ssi_gdd_isr,
 350                                                 0, "gdd_mpu", ssi);
 351         if (err < 0) {
 352                 dev_err(&ssi->device, "Request GDD IRQ %d failed (%d)",
 353                                                         omap_ssi->gdd_irq, err);
 354                 goto out_err;
 355         }
 356
 357         omap_ssi->port = devm_kzalloc(&ssi->device,
 358                 sizeof(struct omap_ssi_port *) * ssi->num_ports, GFP_KERNEL);
 359         if (!omap_ssi->port) {
 360                 err = -ENOMEM;
 361                 goto out_err;
 362         }
 363
 364         omap_ssi->fck = devm_clk_get(&ssi->device, "ssi_ssr_fck");
 365         if (IS_ERR(omap_ssi->fck)) {
 366                 dev_err(&pd->dev, "Could not acquire clock \"ssi_ssr_fck\": %li\n",
 367                         PTR_ERR(omap_ssi->fck));
 368                 err = -ENODEV;
 369                 goto out_err;
 370         }
 371
 372         /* TODO: find register, which can be used to detect context loss */
 373         omap_ssi->get_loss = NULL;
 374
 375         omap_ssi->max_speed = UINT_MAX;
 376         spin_lock_init(&omap_ssi->lock);
 377         err = hsi_register_controller(ssi);
 378
 379         if (err < 0)
 380                 goto out_err;
 381
 382         return 0;
 383
 384 out_err:
 385         ida_simple_remove(&platform_omap_ssi_ida, ssi->id);
 386         return err;
 387 }
 388
 389 static int __init ssi_hw_init(struct hsi_controller *ssi)
 390 {
 391         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 392         unsigned int i;
 393         u32 val;
 394         int err;
 395
 396         err = pm_runtime_get_sync(ssi->device.parent);
 397         if (err < 0) {
 398                 dev_err(&ssi->device, "runtime PM failed %d\n", err);
 399                 return err;
 400         }
 401         /* Reseting SSI controller */
 402         writel_relaxed(SSI_SOFTRESET, omap_ssi->sys + SSI_SYSCONFIG_REG);
 403         val = readl(omap_ssi->sys + SSI_SYSSTATUS_REG);
 404         for (i = 0; ((i < 20) && !(val & SSI_RESETDONE)); i++) {
 405                 msleep(20);
 406                 val = readl(omap_ssi->sys + SSI_SYSSTATUS_REG);
 407         }
 408         if (!(val & SSI_RESETDONE)) {
 409                 dev_err(&ssi->device, "SSI HW reset failed\n");
 410                 pm_runtime_put_sync(ssi->device.parent);
 411                 return -EIO;
 412         }
 413         /* Reseting GDD */
 414         writel_relaxed(SSI_SWRESET, omap_ssi->gdd + SSI_GDD_GRST_REG);
 415         /* Get FCK rate in KHz */
 416         omap_ssi->fck_rate = DIV_ROUND_CLOSEST(ssi_get_clk_rate(ssi), 1000);
 417         dev_dbg(&ssi->device, "SSI fck rate %lu KHz\n", omap_ssi->fck_rate);
 418         /* Set default PM settings */
 419         val = SSI_AUTOIDLE | SSI_SIDLEMODE_SMART | SSI_MIDLEMODE_SMART;
 420         writel_relaxed(val, omap_ssi->sys + SSI_SYSCONFIG_REG);
 421         omap_ssi->sysconfig = val;
 422         writel_relaxed(SSI_CLK_AUTOGATING_ON, omap_ssi->sys + SSI_GDD_GCR_REG);
 423         omap_ssi->gdd_gcr = SSI_CLK_AUTOGATING_ON;
 424         pm_runtime_put_sync(ssi->device.parent);
 425
 426         return 0;
 427 }
 428
 429 static void ssi_remove_controller(struct hsi_controller *ssi)
 430 {
 431         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 432         int id = ssi->id;
 433         tasklet_kill(&omap_ssi->gdd_tasklet);
 434         hsi_unregister_controller(ssi);
 435         ida_simple_remove(&platform_omap_ssi_ida, id);
 436 }
 437
 438 static inline int ssi_of_get_available_ports_count(const struct device_node *np)
 439 {
 440         struct device_node *child;
 441         int num = 0;
 442
 443         for_each_available_child_of_node(np, child)
 444                 if (of_device_is_compatible(child, "ti,omap3-ssi-port"))
 445                         num++;
 446
 447         return num;
 448 }
 449
 450 static int ssi_remove_ports(struct device *dev, void *c)
 451 {
 452         struct platform_device *pdev = to_platform_device(dev);
 453
 454         of_device_unregister(pdev);
 455
 456         return 0;
 457 }
 458
 459 static int __init ssi_probe(struct platform_device *pd)
 460 {
 461         struct platform_device *childpdev;
 462         struct device_node *np = pd->dev.of_node;
 463         struct device_node *child;
 464         struct hsi_controller *ssi;
 465         int err;
 466         int num_ports;
 467
 468         if (!np) {
 469                 dev_err(&pd->dev, "missing device tree data\n");
 470                 return -EINVAL;
 471         }
 472
 473         num_ports = ssi_of_get_available_ports_count(np);
 474
 475         ssi = hsi_alloc_controller(num_ports, GFP_KERNEL);
 476         if (!ssi) {
 477                 dev_err(&pd->dev, "No memory for controller\n");
 478                 return -ENOMEM;
 479         }
 480
 481         platform_set_drvdata(pd, ssi);
 482
 483         err = ssi_add_controller(ssi, pd);
 484         if (err < 0)
 485                 goto out1;
 486
 487         pm_runtime_irq_safe(&pd->dev);
 488         pm_runtime_enable(&pd->dev);
 489
 490         err = ssi_hw_init(ssi);
 491         if (err < 0)
 492                 goto out2;
 493 #ifdef CONFIG_DEBUG_FS
 494         err = ssi_debug_add_ctrl(ssi);
 495         if (err < 0)
 496                 goto out2;
 497 #endif
 498
 499         for_each_available_child_of_node(np, child) {
 500                 if (!of_device_is_compatible(child, "ti,omap3-ssi-port"))
 501                         continue;
 502
 503                 childpdev = of_platform_device_create(child, NULL, &pd->dev);
 504                 if (!childpdev) {
 505                         err = -ENODEV;
 506                         dev_err(&pd->dev, "failed to create ssi controller port\n");
 507                         goto out3;
 508                 }
 509         }
 510
 511         dev_info(&pd->dev, "ssi controller %d initialized (%d ports)!\n",
 512                 ssi->id, num_ports);
 513         return err;
 514 out3:
 515         device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
 516 out2:
 517         ssi_remove_controller(ssi);
 518 out1:
 519         platform_set_drvdata(pd, NULL);
 520         pm_runtime_disable(&pd->dev);
 521
 522         return err;
 523 }
 524
 525 static int __exit ssi_remove(struct platform_device *pd)
 526 {
 527         struct hsi_controller *ssi = platform_get_drvdata(pd);
 528
 529         /* cleanup of of_platform_populate() call */
 530         device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
 531
 532 #ifdef CONFIG_DEBUG_FS
 533         ssi_debug_remove_ctrl(ssi);
 534 #endif
 535         ssi_remove_controller(ssi);
 536         platform_set_drvdata(pd, NULL);
 537
 538         pm_runtime_disable(&pd->dev);
 539
 540         return 0;
 541 }
 542
 543 #ifdef CONFIG_PM
 544 static int omap_ssi_runtime_suspend(struct device *dev)
 545 {
 546         struct hsi_controller *ssi = dev_get_drvdata(dev);
 547         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 548
 549         dev_dbg(dev, "runtime suspend!\n");
 550
 551         if (omap_ssi->get_loss)
 552                 omap_ssi->loss_count =
 553                                 omap_ssi->get_loss(ssi->device.parent);
 554
 555         return 0;
 556 }
 557
 558 static int omap_ssi_runtime_resume(struct device *dev)
 559 {
 560         struct hsi_controller *ssi = dev_get_drvdata(dev);
 561         struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
 562
 563         dev_dbg(dev, "runtime resume!\n");
 564
 565         if ((omap_ssi->get_loss) && (omap_ssi->loss_count ==
 566                                 omap_ssi->get_loss(ssi->device.parent)))
 567                 return 0;
 568
 569         writel_relaxed(omap_ssi->gdd_gcr, omap_ssi->gdd + SSI_GDD_GCR_REG);
 570
 571         return 0;
 572 }
 573
 574 static const struct dev_pm_ops omap_ssi_pm_ops = {
 575         SET_RUNTIME_PM_OPS(omap_ssi_runtime_suspend, omap_ssi_runtime_resume,
 576                 NULL)
 577 };
 578
 579 #define DEV_PM_OPS     (&omap_ssi_pm_ops)
 580 #else
 581 #define DEV_PM_OPS     NULL
 582 #endif
 583
 584 #ifdef CONFIG_OF
 585 static const struct of_device_id omap_ssi_of_match[] = {
 586         { .compatible = "ti,omap3-ssi", },
 587         {},
 588 };
 589 MODULE_DEVICE_TABLE(of, omap_ssi_of_match);
 590 #else
 591 #define omap_ssi_of_match NULL
 592 #endif
 593
 594 static struct platform_driver ssi_pdriver = {
 595         .remove = __exit_p(ssi_remove),
 596         .driver = {
 597                 .name   = "omap_ssi",
 598                 .pm     = DEV_PM_OPS,
 599                 .of_match_table = omap_ssi_of_match,
 600         },
 601 };
 602
 603 module_platform_driver_probe(ssi_pdriver, ssi_probe);
 604
 605 MODULE_ALIAS("platform:omap_ssi");
 606 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
 607 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
 608 MODULE_DESCRIPTION("Synchronous Serial Interface Driver");
 609 MODULE_LICENSE("GPL v2");