xref: /linux/drivers/hsi/controllers/omap_ssi_core.c (revision 3ea5eb68b9d624935108b5e696859304edfac202)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* OMAP SSI driver.
3  *
4  * Copyright (C) 2010 Nokia Corporation. All rights reserved.
5  * Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
6  *
7  * Contact: Carlos Chinea <carlos.chinea@nokia.com>
8  */
9 
10 #include <linux/compiler.h>
11 #include <linux/err.h>
12 #include <linux/ioport.h>
13 #include <linux/io.h>
14 #include <linux/clk.h>
15 #include <linux/device.h>
16 #include <linux/platform_device.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/dmaengine.h>
19 #include <linux/delay.h>
20 #include <linux/hsi/ssi_protocol.h>
21 #include <linux/seq_file.h>
22 #include <linux/scatterlist.h>
23 #include <linux/interrupt.h>
24 #include <linux/spinlock.h>
25 #include <linux/debugfs.h>
26 #include <linux/pinctrl/consumer.h>
27 #include <linux/pm_runtime.h>
28 #include <linux/of.h>
29 #include <linux/of_platform.h>
30 #include <linux/hsi/hsi.h>
31 #include <linux/idr.h>
32 
33 #include "omap_ssi_regs.h"
34 #include "omap_ssi.h"
35 
36 /* For automatically allocated device IDs */
37 static DEFINE_IDA(platform_omap_ssi_ida);
38 
39 #ifdef CONFIG_DEBUG_FS
40 static int ssi_regs_show(struct seq_file *m, void *p __maybe_unused)
41 {
42 	struct hsi_controller *ssi = m->private;
43 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
44 	void __iomem *sys = omap_ssi->sys;
45 
46 	pm_runtime_get_sync(ssi->device.parent);
47 	seq_printf(m, "REVISION\t: 0x%08x\n",  readl(sys + SSI_REVISION_REG));
48 	seq_printf(m, "SYSCONFIG\t: 0x%08x\n", readl(sys + SSI_SYSCONFIG_REG));
49 	seq_printf(m, "SYSSTATUS\t: 0x%08x\n", readl(sys + SSI_SYSSTATUS_REG));
50 	pm_runtime_put(ssi->device.parent);
51 
52 	return 0;
53 }
54 
55 static int ssi_gdd_regs_show(struct seq_file *m, void *p __maybe_unused)
56 {
57 	struct hsi_controller *ssi = m->private;
58 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
59 	void __iomem *gdd = omap_ssi->gdd;
60 	void __iomem *sys = omap_ssi->sys;
61 	int lch;
62 
63 	pm_runtime_get_sync(ssi->device.parent);
64 
65 	seq_printf(m, "GDD_MPU_STATUS\t: 0x%08x\n",
66 		readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG));
67 	seq_printf(m, "GDD_MPU_ENABLE\t: 0x%08x\n\n",
68 		readl(sys + SSI_GDD_MPU_IRQ_ENABLE_REG));
69 	seq_printf(m, "HW_ID\t\t: 0x%08x\n",
70 				readl(gdd + SSI_GDD_HW_ID_REG));
71 	seq_printf(m, "PPORT_ID\t: 0x%08x\n",
72 				readl(gdd + SSI_GDD_PPORT_ID_REG));
73 	seq_printf(m, "MPORT_ID\t: 0x%08x\n",
74 				readl(gdd + SSI_GDD_MPORT_ID_REG));
75 	seq_printf(m, "TEST\t\t: 0x%08x\n",
76 				readl(gdd + SSI_GDD_TEST_REG));
77 	seq_printf(m, "GCR\t\t: 0x%08x\n",
78 				readl(gdd + SSI_GDD_GCR_REG));
79 
80 	for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
81 		seq_printf(m, "\nGDD LCH %d\n=========\n", lch);
82 		seq_printf(m, "CSDP\t\t: 0x%04x\n",
83 				readw(gdd + SSI_GDD_CSDP_REG(lch)));
84 		seq_printf(m, "CCR\t\t: 0x%04x\n",
85 				readw(gdd + SSI_GDD_CCR_REG(lch)));
86 		seq_printf(m, "CICR\t\t: 0x%04x\n",
87 				readw(gdd + SSI_GDD_CICR_REG(lch)));
88 		seq_printf(m, "CSR\t\t: 0x%04x\n",
89 				readw(gdd + SSI_GDD_CSR_REG(lch)));
90 		seq_printf(m, "CSSA\t\t: 0x%08x\n",
91 				readl(gdd + SSI_GDD_CSSA_REG(lch)));
92 		seq_printf(m, "CDSA\t\t: 0x%08x\n",
93 				readl(gdd + SSI_GDD_CDSA_REG(lch)));
94 		seq_printf(m, "CEN\t\t: 0x%04x\n",
95 				readw(gdd + SSI_GDD_CEN_REG(lch)));
96 		seq_printf(m, "CSAC\t\t: 0x%04x\n",
97 				readw(gdd + SSI_GDD_CSAC_REG(lch)));
98 		seq_printf(m, "CDAC\t\t: 0x%04x\n",
99 				readw(gdd + SSI_GDD_CDAC_REG(lch)));
100 		seq_printf(m, "CLNK_CTRL\t: 0x%04x\n",
101 				readw(gdd + SSI_GDD_CLNK_CTRL_REG(lch)));
102 	}
103 
104 	pm_runtime_put(ssi->device.parent);
105 
106 	return 0;
107 }
108 
109 DEFINE_SHOW_ATTRIBUTE(ssi_regs);
110 DEFINE_SHOW_ATTRIBUTE(ssi_gdd_regs);
111 
112 static int ssi_debug_add_ctrl(struct hsi_controller *ssi)
113 {
114 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
115 	struct dentry *dir;
116 
117 	/* SSI controller */
118 	omap_ssi->dir = debugfs_create_dir(dev_name(&ssi->device), NULL);
119 	debugfs_create_file("regs", S_IRUGO, omap_ssi->dir, ssi, &ssi_regs_fops);
120 
121 	/* SSI GDD (DMA) */
122 	dir = debugfs_create_dir("gdd", omap_ssi->dir);
123 	debugfs_create_file("regs", S_IRUGO, dir, ssi, &ssi_gdd_regs_fops);
124 
125 	return 0;
126 }
127 
128 static void ssi_debug_remove_ctrl(struct hsi_controller *ssi)
129 {
130 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
131 
132 	debugfs_remove_recursive(omap_ssi->dir);
133 }
134 #endif /* CONFIG_DEBUG_FS */
135 
136 /*
137  * FIXME: Horrible HACK needed until we remove the useless wakeline test
138  * in the CMT. To be removed !!!!
139  */
140 void ssi_waketest(struct hsi_client *cl, unsigned int enable)
141 {
142 	struct hsi_port *port = hsi_get_port(cl);
143 	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
144 	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
145 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
146 
147 	omap_port->wktest = !!enable;
148 	if (omap_port->wktest) {
149 		pm_runtime_get_sync(ssi->device.parent);
150 		writel_relaxed(SSI_WAKE(0),
151 				omap_ssi->sys + SSI_SET_WAKE_REG(port->num));
152 	} else {
153 		writel_relaxed(SSI_WAKE(0),
154 				omap_ssi->sys +	SSI_CLEAR_WAKE_REG(port->num));
155 		pm_runtime_put(ssi->device.parent);
156 	}
157 }
158 EXPORT_SYMBOL_GPL(ssi_waketest);
159 
160 static void ssi_gdd_complete(struct hsi_controller *ssi, unsigned int lch)
161 {
162 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
163 	struct hsi_msg *msg = omap_ssi->gdd_trn[lch].msg;
164 	struct hsi_port *port = to_hsi_port(msg->cl->device.parent);
165 	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
166 	unsigned int dir;
167 	u32 csr;
168 	u32 val;
169 
170 	spin_lock(&omap_ssi->lock);
171 
172 	val = readl(omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
173 	val &= ~SSI_GDD_LCH(lch);
174 	writel_relaxed(val, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
175 
176 	if (msg->ttype == HSI_MSG_READ) {
177 		dir = DMA_FROM_DEVICE;
178 		val = SSI_DATAAVAILABLE(msg->channel);
179 		pm_runtime_put(omap_port->pdev);
180 	} else {
181 		dir = DMA_TO_DEVICE;
182 		val = SSI_DATAACCEPT(msg->channel);
183 		/* Keep clocks reference for write pio event */
184 	}
185 	dma_unmap_sg(&ssi->device, msg->sgt.sgl, msg->sgt.nents, dir);
186 	csr = readw(omap_ssi->gdd + SSI_GDD_CSR_REG(lch));
187 	omap_ssi->gdd_trn[lch].msg = NULL; /* release GDD lch */
188 	dev_dbg(&port->device, "DMA completed ch %d ttype %d\n",
189 				msg->channel, msg->ttype);
190 	spin_unlock(&omap_ssi->lock);
191 	if (csr & SSI_CSR_TOUR) { /* Timeout error */
192 		msg->status = HSI_STATUS_ERROR;
193 		msg->actual_len = 0;
194 		spin_lock(&omap_port->lock);
195 		list_del(&msg->link); /* Dequeue msg */
196 		spin_unlock(&omap_port->lock);
197 
198 		list_add_tail(&msg->link, &omap_port->errqueue);
199 		schedule_delayed_work(&omap_port->errqueue_work, 0);
200 		return;
201 	}
202 	spin_lock(&omap_port->lock);
203 	val |= readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
204 	writel_relaxed(val, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
205 	spin_unlock(&omap_port->lock);
206 
207 	msg->status = HSI_STATUS_COMPLETED;
208 	msg->actual_len = sg_dma_len(msg->sgt.sgl);
209 }
210 
211 static void ssi_gdd_tasklet(unsigned long dev)
212 {
213 	struct hsi_controller *ssi = (struct hsi_controller *)dev;
214 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
215 	void __iomem *sys = omap_ssi->sys;
216 	unsigned int lch;
217 	u32 status_reg;
218 
219 	pm_runtime_get(ssi->device.parent);
220 
221 	if (!pm_runtime_active(ssi->device.parent)) {
222 		dev_warn(ssi->device.parent, "ssi_gdd_tasklet called without runtime PM!\n");
223 		pm_runtime_put(ssi->device.parent);
224 		return;
225 	}
226 
227 	status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
228 	for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
229 		if (status_reg & SSI_GDD_LCH(lch))
230 			ssi_gdd_complete(ssi, lch);
231 	}
232 	writel_relaxed(status_reg, sys + SSI_GDD_MPU_IRQ_STATUS_REG);
233 	status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
234 
235 	pm_runtime_put(ssi->device.parent);
236 
237 	if (status_reg)
238 		tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
239 	else
240 		enable_irq(omap_ssi->gdd_irq);
241 
242 }
243 
244 static irqreturn_t ssi_gdd_isr(int irq, void *ssi)
245 {
246 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
247 
248 	tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
249 	disable_irq_nosync(irq);
250 
251 	return IRQ_HANDLED;
252 }
253 
254 static unsigned long ssi_get_clk_rate(struct hsi_controller *ssi)
255 {
256 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
257 	unsigned long rate = clk_get_rate(omap_ssi->fck);
258 	return rate;
259 }
260 
261 static int ssi_clk_event(struct notifier_block *nb, unsigned long event,
262 								void *data)
263 {
264 	struct omap_ssi_controller *omap_ssi = container_of(nb,
265 					struct omap_ssi_controller, fck_nb);
266 	struct hsi_controller *ssi = to_hsi_controller(omap_ssi->dev);
267 	struct clk_notifier_data *clk_data = data;
268 	struct omap_ssi_port *omap_port;
269 	int i;
270 
271 	switch (event) {
272 	case PRE_RATE_CHANGE:
273 		dev_dbg(&ssi->device, "pre rate change\n");
274 
275 		for (i = 0; i < ssi->num_ports; i++) {
276 			omap_port = omap_ssi->port[i];
277 
278 			if (!omap_port)
279 				continue;
280 
281 			/* Workaround for SWBREAK + CAwake down race in CMT */
282 			disable_irq(omap_port->wake_irq);
283 
284 			/* stop all ssi communication */
285 			pinctrl_pm_select_idle_state(omap_port->pdev);
286 			udelay(1); /* wait for racing frames */
287 		}
288 
289 		break;
290 	case ABORT_RATE_CHANGE:
291 		dev_dbg(&ssi->device, "abort rate change\n");
292 		fallthrough;
293 	case POST_RATE_CHANGE:
294 		dev_dbg(&ssi->device, "post rate change (%lu -> %lu)\n",
295 			clk_data->old_rate, clk_data->new_rate);
296 		omap_ssi->fck_rate = DIV_ROUND_CLOSEST(clk_data->new_rate, 1000); /* kHz */
297 
298 		for (i = 0; i < ssi->num_ports; i++) {
299 			omap_port = omap_ssi->port[i];
300 
301 			if (!omap_port)
302 				continue;
303 
304 			omap_ssi_port_update_fclk(ssi, omap_port);
305 
306 			/* resume ssi communication */
307 			pinctrl_pm_select_default_state(omap_port->pdev);
308 			enable_irq(omap_port->wake_irq);
309 		}
310 
311 		break;
312 	default:
313 		break;
314 	}
315 
316 	return NOTIFY_DONE;
317 }
318 
319 static int ssi_get_iomem(struct platform_device *pd,
320 		const char *name, void __iomem **pbase, dma_addr_t *phy)
321 {
322 	struct resource *mem;
323 	void __iomem *base;
324 	struct hsi_controller *ssi = platform_get_drvdata(pd);
325 
326 	mem = platform_get_resource_byname(pd, IORESOURCE_MEM, name);
327 	base = devm_ioremap_resource(&ssi->device, mem);
328 	if (IS_ERR(base))
329 		return PTR_ERR(base);
330 
331 	*pbase = base;
332 
333 	if (phy)
334 		*phy = mem->start;
335 
336 	return 0;
337 }
338 
339 static int ssi_add_controller(struct hsi_controller *ssi,
340 						struct platform_device *pd)
341 {
342 	struct omap_ssi_controller *omap_ssi;
343 	int err;
344 
345 	omap_ssi = devm_kzalloc(&ssi->device, sizeof(*omap_ssi), GFP_KERNEL);
346 	if (!omap_ssi)
347 		return -ENOMEM;
348 
349 	err = ida_alloc(&platform_omap_ssi_ida, GFP_KERNEL);
350 	if (err < 0)
351 		return err;
352 	ssi->id = err;
353 
354 	ssi->owner = THIS_MODULE;
355 	ssi->device.parent = &pd->dev;
356 	dev_set_name(&ssi->device, "ssi%d", ssi->id);
357 	hsi_controller_set_drvdata(ssi, omap_ssi);
358 	omap_ssi->dev = &ssi->device;
359 	err = ssi_get_iomem(pd, "sys", &omap_ssi->sys, NULL);
360 	if (err < 0)
361 		goto out_err;
362 	err = ssi_get_iomem(pd, "gdd", &omap_ssi->gdd, NULL);
363 	if (err < 0)
364 		goto out_err;
365 	err = platform_get_irq_byname(pd, "gdd_mpu");
366 	if (err < 0)
367 		goto out_err;
368 	omap_ssi->gdd_irq = err;
369 	tasklet_init(&omap_ssi->gdd_tasklet, ssi_gdd_tasklet,
370 							(unsigned long)ssi);
371 	err = devm_request_irq(&ssi->device, omap_ssi->gdd_irq, ssi_gdd_isr,
372 						0, "gdd_mpu", ssi);
373 	if (err < 0) {
374 		dev_err(&ssi->device, "Request GDD IRQ %d failed (%d)",
375 							omap_ssi->gdd_irq, err);
376 		goto out_err;
377 	}
378 
379 	omap_ssi->port = devm_kcalloc(&ssi->device, ssi->num_ports,
380 				      sizeof(*omap_ssi->port), GFP_KERNEL);
381 	if (!omap_ssi->port) {
382 		err = -ENOMEM;
383 		goto out_err;
384 	}
385 
386 	omap_ssi->fck = devm_clk_get(&ssi->device, "ssi_ssr_fck");
387 	if (IS_ERR(omap_ssi->fck)) {
388 		dev_err(&pd->dev, "Could not acquire clock \"ssi_ssr_fck\": %li\n",
389 			PTR_ERR(omap_ssi->fck));
390 		err = -ENODEV;
391 		goto out_err;
392 	}
393 
394 	omap_ssi->fck_nb.notifier_call = ssi_clk_event;
395 	omap_ssi->fck_nb.priority = INT_MAX;
396 	clk_notifier_register(omap_ssi->fck, &omap_ssi->fck_nb);
397 
398 	/* TODO: find register, which can be used to detect context loss */
399 	omap_ssi->get_loss = NULL;
400 
401 	omap_ssi->max_speed = UINT_MAX;
402 	spin_lock_init(&omap_ssi->lock);
403 	err = hsi_register_controller(ssi);
404 
405 	if (err < 0)
406 		goto out_err;
407 
408 	return 0;
409 
410 out_err:
411 	ida_free(&platform_omap_ssi_ida, ssi->id);
412 	return err;
413 }
414 
415 static int ssi_hw_init(struct hsi_controller *ssi)
416 {
417 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
418 	int err;
419 
420 	err = pm_runtime_resume_and_get(ssi->device.parent);
421 	if (err < 0) {
422 		dev_err(&ssi->device, "runtime PM failed %d\n", err);
423 		return err;
424 	}
425 	/* Resetting GDD */
426 	writel_relaxed(SSI_SWRESET, omap_ssi->gdd + SSI_GDD_GRST_REG);
427 	/* Get FCK rate in kHz */
428 	omap_ssi->fck_rate = DIV_ROUND_CLOSEST(ssi_get_clk_rate(ssi), 1000);
429 	dev_dbg(&ssi->device, "SSI fck rate %lu kHz\n", omap_ssi->fck_rate);
430 
431 	writel_relaxed(SSI_CLK_AUTOGATING_ON, omap_ssi->sys + SSI_GDD_GCR_REG);
432 	omap_ssi->gdd_gcr = SSI_CLK_AUTOGATING_ON;
433 	pm_runtime_put_sync(ssi->device.parent);
434 
435 	return 0;
436 }
437 
438 static void ssi_remove_controller(struct hsi_controller *ssi)
439 {
440 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
441 	int id = ssi->id;
442 	tasklet_kill(&omap_ssi->gdd_tasklet);
443 	hsi_unregister_controller(ssi);
444 	clk_notifier_unregister(omap_ssi->fck, &omap_ssi->fck_nb);
445 	ida_free(&platform_omap_ssi_ida, id);
446 }
447 
448 static inline int ssi_of_get_available_ports_count(const struct device_node *np)
449 {
450 	struct device_node *child;
451 	int num = 0;
452 
453 	for_each_available_child_of_node(np, child)
454 		if (of_device_is_compatible(child, "ti,omap3-ssi-port"))
455 			num++;
456 
457 	return num;
458 }
459 
460 static int ssi_remove_ports(struct device *dev, void *c)
461 {
462 	struct platform_device *pdev = to_platform_device(dev);
463 
464 	if (!dev->of_node)
465 		return 0;
466 
467 	of_node_clear_flag(dev->of_node, OF_POPULATED);
468 	of_device_unregister(pdev);
469 
470 	return 0;
471 }
472 
473 static int ssi_probe(struct platform_device *pd)
474 {
475 	struct platform_device *childpdev;
476 	struct device_node *np = pd->dev.of_node;
477 	struct device_node *child;
478 	struct hsi_controller *ssi;
479 	int err;
480 	int num_ports;
481 
482 	if (!np) {
483 		dev_err(&pd->dev, "missing device tree data\n");
484 		return -EINVAL;
485 	}
486 
487 	num_ports = ssi_of_get_available_ports_count(np);
488 
489 	ssi = hsi_alloc_controller(num_ports, GFP_KERNEL);
490 	if (!ssi) {
491 		dev_err(&pd->dev, "No memory for controller\n");
492 		return -ENOMEM;
493 	}
494 
495 	platform_set_drvdata(pd, ssi);
496 
497 	err = ssi_add_controller(ssi, pd);
498 	if (err < 0) {
499 		hsi_put_controller(ssi);
500 		goto out1;
501 	}
502 
503 	pm_runtime_enable(&pd->dev);
504 
505 	err = ssi_hw_init(ssi);
506 	if (err < 0)
507 		goto out2;
508 #ifdef CONFIG_DEBUG_FS
509 	err = ssi_debug_add_ctrl(ssi);
510 	if (err < 0)
511 		goto out2;
512 #endif
513 
514 	for_each_available_child_of_node(np, child) {
515 		if (!of_device_is_compatible(child, "ti,omap3-ssi-port"))
516 			continue;
517 
518 		childpdev = of_platform_device_create(child, NULL, &pd->dev);
519 		if (!childpdev) {
520 			err = -ENODEV;
521 			dev_err(&pd->dev, "failed to create ssi controller port\n");
522 			of_node_put(child);
523 			goto out3;
524 		}
525 	}
526 
527 	dev_info(&pd->dev, "ssi controller %d initialized (%d ports)!\n",
528 		ssi->id, num_ports);
529 	return err;
530 out3:
531 	device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
532 out2:
533 	ssi_remove_controller(ssi);
534 	pm_runtime_disable(&pd->dev);
535 out1:
536 	platform_set_drvdata(pd, NULL);
537 
538 	return err;
539 }
540 
541 static void ssi_remove(struct platform_device *pd)
542 {
543 	struct hsi_controller *ssi = platform_get_drvdata(pd);
544 
545 	/* cleanup of of_platform_populate() call */
546 	device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
547 
548 #ifdef CONFIG_DEBUG_FS
549 	ssi_debug_remove_ctrl(ssi);
550 #endif
551 	ssi_remove_controller(ssi);
552 	platform_set_drvdata(pd, NULL);
553 
554 	pm_runtime_disable(&pd->dev);
555 }
556 
557 #ifdef CONFIG_PM
558 static int omap_ssi_runtime_suspend(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 suspend!\n");
564 
565 	if (omap_ssi->get_loss)
566 		omap_ssi->loss_count =
567 				omap_ssi->get_loss(ssi->device.parent);
568 
569 	return 0;
570 }
571 
572 static int omap_ssi_runtime_resume(struct device *dev)
573 {
574 	struct hsi_controller *ssi = dev_get_drvdata(dev);
575 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
576 
577 	dev_dbg(dev, "runtime resume!\n");
578 
579 	if ((omap_ssi->get_loss) && (omap_ssi->loss_count ==
580 				omap_ssi->get_loss(ssi->device.parent)))
581 		return 0;
582 
583 	writel_relaxed(omap_ssi->gdd_gcr, omap_ssi->gdd + SSI_GDD_GCR_REG);
584 
585 	return 0;
586 }
587 
588 static const struct dev_pm_ops omap_ssi_pm_ops = {
589 	SET_RUNTIME_PM_OPS(omap_ssi_runtime_suspend, omap_ssi_runtime_resume,
590 		NULL)
591 };
592 
593 #define DEV_PM_OPS     (&omap_ssi_pm_ops)
594 #else
595 #define DEV_PM_OPS     NULL
596 #endif
597 
598 #ifdef CONFIG_OF
599 static const struct of_device_id omap_ssi_of_match[] = {
600 	{ .compatible = "ti,omap3-ssi", },
601 	{},
602 };
603 MODULE_DEVICE_TABLE(of, omap_ssi_of_match);
604 #else
605 #define omap_ssi_of_match NULL
606 #endif
607 
608 static struct platform_driver ssi_pdriver = {
609 	.probe = ssi_probe,
610 	.remove_new = ssi_remove,
611 	.driver	= {
612 		.name	= "omap_ssi",
613 		.pm     = DEV_PM_OPS,
614 		.of_match_table = omap_ssi_of_match,
615 	},
616 };
617 
618 static int __init ssi_init(void) {
619 	int ret;
620 
621 	ret = platform_driver_register(&ssi_pdriver);
622 	if (ret)
623 		return ret;
624 
625 	ret = platform_driver_register(&ssi_port_pdriver);
626 	if (ret) {
627 		platform_driver_unregister(&ssi_pdriver);
628 		return ret;
629 	}
630 
631 	return 0;
632 }
633 module_init(ssi_init);
634 
635 static void __exit ssi_exit(void) {
636 	platform_driver_unregister(&ssi_port_pdriver);
637 	platform_driver_unregister(&ssi_pdriver);
638 }
639 module_exit(ssi_exit);
640 
641 MODULE_ALIAS("platform:omap_ssi");
642 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
643 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
644 MODULE_DESCRIPTION("Synchronous Serial Interface Driver");
645 MODULE_LICENSE("GPL v2");
646