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