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 	if (!omap_ssi->dir)
120 		return -ENOMEM;
121 
122 	debugfs_create_file("regs", S_IRUGO, omap_ssi->dir, ssi,
123 								&ssi_regs_fops);
124 	/* SSI GDD (DMA) */
125 	dir = debugfs_create_dir("gdd", omap_ssi->dir);
126 	if (!dir)
127 		goto rback;
128 	debugfs_create_file("regs", S_IRUGO, dir, ssi, &ssi_gdd_regs_fops);
129 
130 	return 0;
131 rback:
132 	debugfs_remove_recursive(omap_ssi->dir);
133 
134 	return -ENOMEM;
135 }
136 
137 static void ssi_debug_remove_ctrl(struct hsi_controller *ssi)
138 {
139 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
140 
141 	debugfs_remove_recursive(omap_ssi->dir);
142 }
143 #endif /* CONFIG_DEBUG_FS */
144 
145 /*
146  * FIXME: Horrible HACK needed until we remove the useless wakeline test
147  * in the CMT. To be removed !!!!
148  */
149 void ssi_waketest(struct hsi_client *cl, unsigned int enable)
150 {
151 	struct hsi_port *port = hsi_get_port(cl);
152 	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
153 	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
154 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
155 
156 	omap_port->wktest = !!enable;
157 	if (omap_port->wktest) {
158 		pm_runtime_get_sync(ssi->device.parent);
159 		writel_relaxed(SSI_WAKE(0),
160 				omap_ssi->sys + SSI_SET_WAKE_REG(port->num));
161 	} else {
162 		writel_relaxed(SSI_WAKE(0),
163 				omap_ssi->sys +	SSI_CLEAR_WAKE_REG(port->num));
164 		pm_runtime_put(ssi->device.parent);
165 	}
166 }
167 EXPORT_SYMBOL_GPL(ssi_waketest);
168 
169 static void ssi_gdd_complete(struct hsi_controller *ssi, unsigned int lch)
170 {
171 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
172 	struct hsi_msg *msg = omap_ssi->gdd_trn[lch].msg;
173 	struct hsi_port *port = to_hsi_port(msg->cl->device.parent);
174 	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
175 	unsigned int dir;
176 	u32 csr;
177 	u32 val;
178 
179 	spin_lock(&omap_ssi->lock);
180 
181 	val = readl(omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
182 	val &= ~SSI_GDD_LCH(lch);
183 	writel_relaxed(val, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
184 
185 	if (msg->ttype == HSI_MSG_READ) {
186 		dir = DMA_FROM_DEVICE;
187 		val = SSI_DATAAVAILABLE(msg->channel);
188 		pm_runtime_put(omap_port->pdev);
189 	} else {
190 		dir = DMA_TO_DEVICE;
191 		val = SSI_DATAACCEPT(msg->channel);
192 		/* Keep clocks reference for write pio event */
193 	}
194 	dma_unmap_sg(&ssi->device, msg->sgt.sgl, msg->sgt.nents, dir);
195 	csr = readw(omap_ssi->gdd + SSI_GDD_CSR_REG(lch));
196 	omap_ssi->gdd_trn[lch].msg = NULL; /* release GDD lch */
197 	dev_dbg(&port->device, "DMA completed ch %d ttype %d\n",
198 				msg->channel, msg->ttype);
199 	spin_unlock(&omap_ssi->lock);
200 	if (csr & SSI_CSR_TOUR) { /* Timeout error */
201 		msg->status = HSI_STATUS_ERROR;
202 		msg->actual_len = 0;
203 		spin_lock(&omap_port->lock);
204 		list_del(&msg->link); /* Dequeue msg */
205 		spin_unlock(&omap_port->lock);
206 
207 		list_add_tail(&msg->link, &omap_port->errqueue);
208 		schedule_delayed_work(&omap_port->errqueue_work, 0);
209 		return;
210 	}
211 	spin_lock(&omap_port->lock);
212 	val |= readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
213 	writel_relaxed(val, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
214 	spin_unlock(&omap_port->lock);
215 
216 	msg->status = HSI_STATUS_COMPLETED;
217 	msg->actual_len = sg_dma_len(msg->sgt.sgl);
218 }
219 
220 static void ssi_gdd_tasklet(unsigned long dev)
221 {
222 	struct hsi_controller *ssi = (struct hsi_controller *)dev;
223 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
224 	void __iomem *sys = omap_ssi->sys;
225 	unsigned int lch;
226 	u32 status_reg;
227 
228 	pm_runtime_get(ssi->device.parent);
229 
230 	if (!pm_runtime_active(ssi->device.parent)) {
231 		dev_warn(ssi->device.parent, "ssi_gdd_tasklet called without runtime PM!\n");
232 		pm_runtime_put(ssi->device.parent);
233 		return;
234 	}
235 
236 	status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
237 	for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
238 		if (status_reg & SSI_GDD_LCH(lch))
239 			ssi_gdd_complete(ssi, lch);
240 	}
241 	writel_relaxed(status_reg, sys + SSI_GDD_MPU_IRQ_STATUS_REG);
242 	status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
243 
244 	pm_runtime_put(ssi->device.parent);
245 
246 	if (status_reg)
247 		tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
248 	else
249 		enable_irq(omap_ssi->gdd_irq);
250 
251 }
252 
253 static irqreturn_t ssi_gdd_isr(int irq, void *ssi)
254 {
255 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
256 
257 	tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
258 	disable_irq_nosync(irq);
259 
260 	return IRQ_HANDLED;
261 }
262 
263 static unsigned long ssi_get_clk_rate(struct hsi_controller *ssi)
264 {
265 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
266 	unsigned long rate = clk_get_rate(omap_ssi->fck);
267 	return rate;
268 }
269 
270 static int ssi_clk_event(struct notifier_block *nb, unsigned long event,
271 								void *data)
272 {
273 	struct omap_ssi_controller *omap_ssi = container_of(nb,
274 					struct omap_ssi_controller, fck_nb);
275 	struct hsi_controller *ssi = to_hsi_controller(omap_ssi->dev);
276 	struct clk_notifier_data *clk_data = data;
277 	struct omap_ssi_port *omap_port;
278 	int i;
279 
280 	switch (event) {
281 	case PRE_RATE_CHANGE:
282 		dev_dbg(&ssi->device, "pre rate change\n");
283 
284 		for (i = 0; i < ssi->num_ports; i++) {
285 			omap_port = omap_ssi->port[i];
286 
287 			if (!omap_port)
288 				continue;
289 
290 			/* Workaround for SWBREAK + CAwake down race in CMT */
291 			disable_irq(omap_port->wake_irq);
292 
293 			/* stop all ssi communication */
294 			pinctrl_pm_select_idle_state(omap_port->pdev);
295 			udelay(1); /* wait for racing frames */
296 		}
297 
298 		break;
299 	case ABORT_RATE_CHANGE:
300 		dev_dbg(&ssi->device, "abort rate change\n");
301 		fallthrough;
302 	case POST_RATE_CHANGE:
303 		dev_dbg(&ssi->device, "post rate change (%lu -> %lu)\n",
304 			clk_data->old_rate, clk_data->new_rate);
305 		omap_ssi->fck_rate = DIV_ROUND_CLOSEST(clk_data->new_rate, 1000); /* kHz */
306 
307 		for (i = 0; i < ssi->num_ports; i++) {
308 			omap_port = omap_ssi->port[i];
309 
310 			if (!omap_port)
311 				continue;
312 
313 			omap_ssi_port_update_fclk(ssi, omap_port);
314 
315 			/* resume ssi communication */
316 			pinctrl_pm_select_default_state(omap_port->pdev);
317 			enable_irq(omap_port->wake_irq);
318 		}
319 
320 		break;
321 	default:
322 		break;
323 	}
324 
325 	return NOTIFY_DONE;
326 }
327 
328 static int ssi_get_iomem(struct platform_device *pd,
329 		const char *name, void __iomem **pbase, dma_addr_t *phy)
330 {
331 	struct resource *mem;
332 	void __iomem *base;
333 	struct hsi_controller *ssi = platform_get_drvdata(pd);
334 
335 	mem = platform_get_resource_byname(pd, IORESOURCE_MEM, name);
336 	base = devm_ioremap_resource(&ssi->device, mem);
337 	if (IS_ERR(base))
338 		return PTR_ERR(base);
339 
340 	*pbase = base;
341 
342 	if (phy)
343 		*phy = mem->start;
344 
345 	return 0;
346 }
347 
348 static int ssi_add_controller(struct hsi_controller *ssi,
349 						struct platform_device *pd)
350 {
351 	struct omap_ssi_controller *omap_ssi;
352 	int err;
353 
354 	omap_ssi = devm_kzalloc(&ssi->device, sizeof(*omap_ssi), GFP_KERNEL);
355 	if (!omap_ssi)
356 		return -ENOMEM;
357 
358 	err = ida_simple_get(&platform_omap_ssi_ida, 0, 0, GFP_KERNEL);
359 	if (err < 0)
360 		return err;
361 	ssi->id = err;
362 
363 	ssi->owner = THIS_MODULE;
364 	ssi->device.parent = &pd->dev;
365 	dev_set_name(&ssi->device, "ssi%d", ssi->id);
366 	hsi_controller_set_drvdata(ssi, omap_ssi);
367 	omap_ssi->dev = &ssi->device;
368 	err = ssi_get_iomem(pd, "sys", &omap_ssi->sys, NULL);
369 	if (err < 0)
370 		goto out_err;
371 	err = ssi_get_iomem(pd, "gdd", &omap_ssi->gdd, NULL);
372 	if (err < 0)
373 		goto out_err;
374 	err = platform_get_irq_byname(pd, "gdd_mpu");
375 	if (err < 0)
376 		goto out_err;
377 	omap_ssi->gdd_irq = err;
378 	tasklet_init(&omap_ssi->gdd_tasklet, ssi_gdd_tasklet,
379 							(unsigned long)ssi);
380 	err = devm_request_irq(&ssi->device, omap_ssi->gdd_irq, ssi_gdd_isr,
381 						0, "gdd_mpu", ssi);
382 	if (err < 0) {
383 		dev_err(&ssi->device, "Request GDD IRQ %d failed (%d)",
384 							omap_ssi->gdd_irq, err);
385 		goto out_err;
386 	}
387 
388 	omap_ssi->port = devm_kcalloc(&ssi->device, ssi->num_ports,
389 				      sizeof(*omap_ssi->port), GFP_KERNEL);
390 	if (!omap_ssi->port) {
391 		err = -ENOMEM;
392 		goto out_err;
393 	}
394 
395 	omap_ssi->fck = devm_clk_get(&ssi->device, "ssi_ssr_fck");
396 	if (IS_ERR(omap_ssi->fck)) {
397 		dev_err(&pd->dev, "Could not acquire clock \"ssi_ssr_fck\": %li\n",
398 			PTR_ERR(omap_ssi->fck));
399 		err = -ENODEV;
400 		goto out_err;
401 	}
402 
403 	omap_ssi->fck_nb.notifier_call = ssi_clk_event;
404 	omap_ssi->fck_nb.priority = INT_MAX;
405 	clk_notifier_register(omap_ssi->fck, &omap_ssi->fck_nb);
406 
407 	/* TODO: find register, which can be used to detect context loss */
408 	omap_ssi->get_loss = NULL;
409 
410 	omap_ssi->max_speed = UINT_MAX;
411 	spin_lock_init(&omap_ssi->lock);
412 	err = hsi_register_controller(ssi);
413 
414 	if (err < 0)
415 		goto out_err;
416 
417 	return 0;
418 
419 out_err:
420 	ida_simple_remove(&platform_omap_ssi_ida, ssi->id);
421 	return err;
422 }
423 
424 static int ssi_hw_init(struct hsi_controller *ssi)
425 {
426 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
427 	int err;
428 
429 	err = pm_runtime_resume_and_get(ssi->device.parent);
430 	if (err < 0) {
431 		dev_err(&ssi->device, "runtime PM failed %d\n", err);
432 		return err;
433 	}
434 	/* Resetting GDD */
435 	writel_relaxed(SSI_SWRESET, omap_ssi->gdd + SSI_GDD_GRST_REG);
436 	/* Get FCK rate in kHz */
437 	omap_ssi->fck_rate = DIV_ROUND_CLOSEST(ssi_get_clk_rate(ssi), 1000);
438 	dev_dbg(&ssi->device, "SSI fck rate %lu kHz\n", omap_ssi->fck_rate);
439 
440 	writel_relaxed(SSI_CLK_AUTOGATING_ON, omap_ssi->sys + SSI_GDD_GCR_REG);
441 	omap_ssi->gdd_gcr = SSI_CLK_AUTOGATING_ON;
442 	pm_runtime_put_sync(ssi->device.parent);
443 
444 	return 0;
445 }
446 
447 static void ssi_remove_controller(struct hsi_controller *ssi)
448 {
449 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
450 	int id = ssi->id;
451 	tasklet_kill(&omap_ssi->gdd_tasklet);
452 	hsi_unregister_controller(ssi);
453 	clk_notifier_unregister(omap_ssi->fck, &omap_ssi->fck_nb);
454 	ida_simple_remove(&platform_omap_ssi_ida, id);
455 }
456 
457 static inline int ssi_of_get_available_ports_count(const struct device_node *np)
458 {
459 	struct device_node *child;
460 	int num = 0;
461 
462 	for_each_available_child_of_node(np, child)
463 		if (of_device_is_compatible(child, "ti,omap3-ssi-port"))
464 			num++;
465 
466 	return num;
467 }
468 
469 static int ssi_remove_ports(struct device *dev, void *c)
470 {
471 	struct platform_device *pdev = to_platform_device(dev);
472 
473 	if (!dev->of_node)
474 		return 0;
475 
476 	of_node_clear_flag(dev->of_node, OF_POPULATED);
477 	of_device_unregister(pdev);
478 
479 	return 0;
480 }
481 
482 static int ssi_probe(struct platform_device *pd)
483 {
484 	struct platform_device *childpdev;
485 	struct device_node *np = pd->dev.of_node;
486 	struct device_node *child;
487 	struct hsi_controller *ssi;
488 	int err;
489 	int num_ports;
490 
491 	if (!np) {
492 		dev_err(&pd->dev, "missing device tree data\n");
493 		return -EINVAL;
494 	}
495 
496 	num_ports = ssi_of_get_available_ports_count(np);
497 
498 	ssi = hsi_alloc_controller(num_ports, GFP_KERNEL);
499 	if (!ssi) {
500 		dev_err(&pd->dev, "No memory for controller\n");
501 		return -ENOMEM;
502 	}
503 
504 	platform_set_drvdata(pd, ssi);
505 
506 	err = ssi_add_controller(ssi, pd);
507 	if (err < 0) {
508 		hsi_put_controller(ssi);
509 		goto out1;
510 	}
511 
512 	pm_runtime_enable(&pd->dev);
513 
514 	err = ssi_hw_init(ssi);
515 	if (err < 0)
516 		goto out2;
517 #ifdef CONFIG_DEBUG_FS
518 	err = ssi_debug_add_ctrl(ssi);
519 	if (err < 0)
520 		goto out2;
521 #endif
522 
523 	for_each_available_child_of_node(np, child) {
524 		if (!of_device_is_compatible(child, "ti,omap3-ssi-port"))
525 			continue;
526 
527 		childpdev = of_platform_device_create(child, NULL, &pd->dev);
528 		if (!childpdev) {
529 			err = -ENODEV;
530 			dev_err(&pd->dev, "failed to create ssi controller port\n");
531 			of_node_put(child);
532 			goto out3;
533 		}
534 	}
535 
536 	dev_info(&pd->dev, "ssi controller %d initialized (%d ports)!\n",
537 		ssi->id, num_ports);
538 	return err;
539 out3:
540 	device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
541 out2:
542 	ssi_remove_controller(ssi);
543 	pm_runtime_disable(&pd->dev);
544 out1:
545 	platform_set_drvdata(pd, NULL);
546 
547 	return err;
548 }
549 
550 static int ssi_remove(struct platform_device *pd)
551 {
552 	struct hsi_controller *ssi = platform_get_drvdata(pd);
553 
554 	/* cleanup of of_platform_populate() call */
555 	device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
556 
557 #ifdef CONFIG_DEBUG_FS
558 	ssi_debug_remove_ctrl(ssi);
559 #endif
560 	ssi_remove_controller(ssi);
561 	platform_set_drvdata(pd, NULL);
562 
563 	pm_runtime_disable(&pd->dev);
564 
565 	return 0;
566 }
567 
568 #ifdef CONFIG_PM
569 static int omap_ssi_runtime_suspend(struct device *dev)
570 {
571 	struct hsi_controller *ssi = dev_get_drvdata(dev);
572 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
573 
574 	dev_dbg(dev, "runtime suspend!\n");
575 
576 	if (omap_ssi->get_loss)
577 		omap_ssi->loss_count =
578 				omap_ssi->get_loss(ssi->device.parent);
579 
580 	return 0;
581 }
582 
583 static int omap_ssi_runtime_resume(struct device *dev)
584 {
585 	struct hsi_controller *ssi = dev_get_drvdata(dev);
586 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
587 
588 	dev_dbg(dev, "runtime resume!\n");
589 
590 	if ((omap_ssi->get_loss) && (omap_ssi->loss_count ==
591 				omap_ssi->get_loss(ssi->device.parent)))
592 		return 0;
593 
594 	writel_relaxed(omap_ssi->gdd_gcr, omap_ssi->gdd + SSI_GDD_GCR_REG);
595 
596 	return 0;
597 }
598 
599 static const struct dev_pm_ops omap_ssi_pm_ops = {
600 	SET_RUNTIME_PM_OPS(omap_ssi_runtime_suspend, omap_ssi_runtime_resume,
601 		NULL)
602 };
603 
604 #define DEV_PM_OPS     (&omap_ssi_pm_ops)
605 #else
606 #define DEV_PM_OPS     NULL
607 #endif
608 
609 #ifdef CONFIG_OF
610 static const struct of_device_id omap_ssi_of_match[] = {
611 	{ .compatible = "ti,omap3-ssi", },
612 	{},
613 };
614 MODULE_DEVICE_TABLE(of, omap_ssi_of_match);
615 #else
616 #define omap_ssi_of_match NULL
617 #endif
618 
619 static struct platform_driver ssi_pdriver = {
620 	.probe = ssi_probe,
621 	.remove	= ssi_remove,
622 	.driver	= {
623 		.name	= "omap_ssi",
624 		.pm     = DEV_PM_OPS,
625 		.of_match_table = omap_ssi_of_match,
626 	},
627 };
628 
629 static int __init ssi_init(void) {
630 	int ret;
631 
632 	ret = platform_driver_register(&ssi_pdriver);
633 	if (ret)
634 		return ret;
635 
636 	ret = platform_driver_register(&ssi_port_pdriver);
637 	if (ret) {
638 		platform_driver_unregister(&ssi_pdriver);
639 		return ret;
640 	}
641 
642 	return 0;
643 }
644 module_init(ssi_init);
645 
646 static void __exit ssi_exit(void) {
647 	platform_driver_unregister(&ssi_port_pdriver);
648 	platform_driver_unregister(&ssi_pdriver);
649 }
650 module_exit(ssi_exit);
651 
652 MODULE_ALIAS("platform:omap_ssi");
653 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
654 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
655 MODULE_DESCRIPTION("Synchronous Serial Interface Driver");
656 MODULE_LICENSE("GPL v2");
657