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/pinctrl/consumer.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(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(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 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(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(omap_port->pdev);
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 
239 		list_add_tail(&msg->link, &omap_port->errqueue);
240 		schedule_delayed_work(&omap_port->errqueue_work, 0);
241 		return;
242 	}
243 	spin_lock(&omap_port->lock);
244 	val |= readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
245 	writel_relaxed(val, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
246 	spin_unlock(&omap_port->lock);
247 
248 	msg->status = HSI_STATUS_COMPLETED;
249 	msg->actual_len = sg_dma_len(msg->sgt.sgl);
250 }
251 
252 static void ssi_gdd_tasklet(unsigned long dev)
253 {
254 	struct hsi_controller *ssi = (struct hsi_controller *)dev;
255 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
256 	void __iomem *sys = omap_ssi->sys;
257 	unsigned int lch;
258 	u32 status_reg;
259 
260 	pm_runtime_get(ssi->device.parent);
261 
262 	if (!pm_runtime_active(ssi->device.parent)) {
263 		dev_warn(ssi->device.parent, "ssi_gdd_tasklet called without runtime PM!\n");
264 		pm_runtime_put(ssi->device.parent);
265 		return;
266 	}
267 
268 	status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
269 	for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
270 		if (status_reg & SSI_GDD_LCH(lch))
271 			ssi_gdd_complete(ssi, lch);
272 	}
273 	writel_relaxed(status_reg, sys + SSI_GDD_MPU_IRQ_STATUS_REG);
274 	status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
275 
276 	pm_runtime_put(ssi->device.parent);
277 
278 	if (status_reg)
279 		tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
280 	else
281 		enable_irq(omap_ssi->gdd_irq);
282 
283 }
284 
285 static irqreturn_t ssi_gdd_isr(int irq, void *ssi)
286 {
287 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
288 
289 	tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
290 	disable_irq_nosync(irq);
291 
292 	return IRQ_HANDLED;
293 }
294 
295 static unsigned long ssi_get_clk_rate(struct hsi_controller *ssi)
296 {
297 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
298 	unsigned long rate = clk_get_rate(omap_ssi->fck);
299 	return rate;
300 }
301 
302 static int ssi_clk_event(struct notifier_block *nb, unsigned long event,
303 								void *data)
304 {
305 	struct omap_ssi_controller *omap_ssi = container_of(nb,
306 					struct omap_ssi_controller, fck_nb);
307 	struct hsi_controller *ssi = to_hsi_controller(omap_ssi->dev);
308 	struct clk_notifier_data *clk_data = data;
309 	struct omap_ssi_port *omap_port;
310 	int i;
311 
312 	switch (event) {
313 	case PRE_RATE_CHANGE:
314 		dev_dbg(&ssi->device, "pre rate change\n");
315 
316 		for (i = 0; i < ssi->num_ports; i++) {
317 			omap_port = omap_ssi->port[i];
318 
319 			if (!omap_port)
320 				continue;
321 
322 			/* Workaround for SWBREAK + CAwake down race in CMT */
323 			disable_irq(omap_port->wake_irq);
324 
325 			/* stop all ssi communication */
326 			pinctrl_pm_select_idle_state(omap_port->pdev);
327 			udelay(1); /* wait for racing frames */
328 		}
329 
330 		break;
331 	case ABORT_RATE_CHANGE:
332 		dev_dbg(&ssi->device, "abort rate change\n");
333 		/* Fall through */
334 	case POST_RATE_CHANGE:
335 		dev_dbg(&ssi->device, "post rate change (%lu -> %lu)\n",
336 			clk_data->old_rate, clk_data->new_rate);
337 		omap_ssi->fck_rate = DIV_ROUND_CLOSEST(clk_data->new_rate, 1000); /* KHz */
338 
339 		for (i = 0; i < ssi->num_ports; i++) {
340 			omap_port = omap_ssi->port[i];
341 
342 			if (!omap_port)
343 				continue;
344 
345 			omap_ssi_port_update_fclk(ssi, omap_port);
346 
347 			/* resume ssi communication */
348 			pinctrl_pm_select_default_state(omap_port->pdev);
349 			enable_irq(omap_port->wake_irq);
350 		}
351 
352 		break;
353 	default:
354 		break;
355 	}
356 
357 	return NOTIFY_DONE;
358 }
359 
360 static int ssi_get_iomem(struct platform_device *pd,
361 		const char *name, void __iomem **pbase, dma_addr_t *phy)
362 {
363 	struct resource *mem;
364 	void __iomem *base;
365 	struct hsi_controller *ssi = platform_get_drvdata(pd);
366 
367 	mem = platform_get_resource_byname(pd, IORESOURCE_MEM, name);
368 	base = devm_ioremap_resource(&ssi->device, mem);
369 	if (IS_ERR(base))
370 		return PTR_ERR(base);
371 
372 	*pbase = base;
373 
374 	if (phy)
375 		*phy = mem->start;
376 
377 	return 0;
378 }
379 
380 static int ssi_add_controller(struct hsi_controller *ssi,
381 						struct platform_device *pd)
382 {
383 	struct omap_ssi_controller *omap_ssi;
384 	int err;
385 
386 	omap_ssi = devm_kzalloc(&ssi->device, sizeof(*omap_ssi), GFP_KERNEL);
387 	if (!omap_ssi) {
388 		dev_err(&pd->dev, "not enough memory for omap ssi\n");
389 		return -ENOMEM;
390 	}
391 
392 	err = ida_simple_get(&platform_omap_ssi_ida, 0, 0, GFP_KERNEL);
393 	if (err < 0)
394 		goto out_err;
395 	ssi->id = err;
396 
397 	ssi->owner = THIS_MODULE;
398 	ssi->device.parent = &pd->dev;
399 	dev_set_name(&ssi->device, "ssi%d", ssi->id);
400 	hsi_controller_set_drvdata(ssi, omap_ssi);
401 	omap_ssi->dev = &ssi->device;
402 	err = ssi_get_iomem(pd, "sys", &omap_ssi->sys, NULL);
403 	if (err < 0)
404 		goto out_err;
405 	err = ssi_get_iomem(pd, "gdd", &omap_ssi->gdd, NULL);
406 	if (err < 0)
407 		goto out_err;
408 	err = platform_get_irq_byname(pd, "gdd_mpu");
409 	if (err < 0) {
410 		dev_err(&pd->dev, "GDD IRQ resource missing\n");
411 		goto out_err;
412 	}
413 	omap_ssi->gdd_irq = err;
414 	tasklet_init(&omap_ssi->gdd_tasklet, ssi_gdd_tasklet,
415 							(unsigned long)ssi);
416 	err = devm_request_irq(&ssi->device, omap_ssi->gdd_irq, ssi_gdd_isr,
417 						0, "gdd_mpu", ssi);
418 	if (err < 0) {
419 		dev_err(&ssi->device, "Request GDD IRQ %d failed (%d)",
420 							omap_ssi->gdd_irq, err);
421 		goto out_err;
422 	}
423 
424 	omap_ssi->port = devm_kzalloc(&ssi->device,
425 		sizeof(struct omap_ssi_port *) * ssi->num_ports, GFP_KERNEL);
426 	if (!omap_ssi->port) {
427 		err = -ENOMEM;
428 		goto out_err;
429 	}
430 
431 	omap_ssi->fck = devm_clk_get(&ssi->device, "ssi_ssr_fck");
432 	if (IS_ERR(omap_ssi->fck)) {
433 		dev_err(&pd->dev, "Could not acquire clock \"ssi_ssr_fck\": %li\n",
434 			PTR_ERR(omap_ssi->fck));
435 		err = -ENODEV;
436 		goto out_err;
437 	}
438 
439 	omap_ssi->fck_nb.notifier_call = ssi_clk_event;
440 	omap_ssi->fck_nb.priority = INT_MAX;
441 	clk_notifier_register(omap_ssi->fck, &omap_ssi->fck_nb);
442 
443 	/* TODO: find register, which can be used to detect context loss */
444 	omap_ssi->get_loss = NULL;
445 
446 	omap_ssi->max_speed = UINT_MAX;
447 	spin_lock_init(&omap_ssi->lock);
448 	err = hsi_register_controller(ssi);
449 
450 	if (err < 0)
451 		goto out_err;
452 
453 	return 0;
454 
455 out_err:
456 	ida_simple_remove(&platform_omap_ssi_ida, ssi->id);
457 	return err;
458 }
459 
460 static int ssi_hw_init(struct hsi_controller *ssi)
461 {
462 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
463 	int err;
464 
465 	err = pm_runtime_get_sync(ssi->device.parent);
466 	if (err < 0) {
467 		dev_err(&ssi->device, "runtime PM failed %d\n", err);
468 		return err;
469 	}
470 	/* Reseting GDD */
471 	writel_relaxed(SSI_SWRESET, omap_ssi->gdd + SSI_GDD_GRST_REG);
472 	/* Get FCK rate in KHz */
473 	omap_ssi->fck_rate = DIV_ROUND_CLOSEST(ssi_get_clk_rate(ssi), 1000);
474 	dev_dbg(&ssi->device, "SSI fck rate %lu KHz\n", omap_ssi->fck_rate);
475 
476 	writel_relaxed(SSI_CLK_AUTOGATING_ON, omap_ssi->sys + SSI_GDD_GCR_REG);
477 	omap_ssi->gdd_gcr = SSI_CLK_AUTOGATING_ON;
478 	pm_runtime_put_sync(ssi->device.parent);
479 
480 	return 0;
481 }
482 
483 static void ssi_remove_controller(struct hsi_controller *ssi)
484 {
485 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
486 	int id = ssi->id;
487 	tasklet_kill(&omap_ssi->gdd_tasklet);
488 	hsi_unregister_controller(ssi);
489 	clk_notifier_unregister(omap_ssi->fck, &omap_ssi->fck_nb);
490 	ida_simple_remove(&platform_omap_ssi_ida, id);
491 }
492 
493 static inline int ssi_of_get_available_ports_count(const struct device_node *np)
494 {
495 	struct device_node *child;
496 	int num = 0;
497 
498 	for_each_available_child_of_node(np, child)
499 		if (of_device_is_compatible(child, "ti,omap3-ssi-port"))
500 			num++;
501 
502 	return num;
503 }
504 
505 static int ssi_remove_ports(struct device *dev, void *c)
506 {
507 	struct platform_device *pdev = to_platform_device(dev);
508 
509 	if (!dev->of_node)
510 		return 0;
511 
512 	of_node_clear_flag(dev->of_node, OF_POPULATED);
513 	of_device_unregister(pdev);
514 
515 	return 0;
516 }
517 
518 static int ssi_probe(struct platform_device *pd)
519 {
520 	struct platform_device *childpdev;
521 	struct device_node *np = pd->dev.of_node;
522 	struct device_node *child;
523 	struct hsi_controller *ssi;
524 	int err;
525 	int num_ports;
526 
527 	if (!np) {
528 		dev_err(&pd->dev, "missing device tree data\n");
529 		return -EINVAL;
530 	}
531 
532 	num_ports = ssi_of_get_available_ports_count(np);
533 
534 	ssi = hsi_alloc_controller(num_ports, GFP_KERNEL);
535 	if (!ssi) {
536 		dev_err(&pd->dev, "No memory for controller\n");
537 		return -ENOMEM;
538 	}
539 
540 	platform_set_drvdata(pd, ssi);
541 
542 	err = ssi_add_controller(ssi, pd);
543 	if (err < 0)
544 		goto out1;
545 
546 	pm_runtime_enable(&pd->dev);
547 
548 	err = ssi_hw_init(ssi);
549 	if (err < 0)
550 		goto out2;
551 #ifdef CONFIG_DEBUG_FS
552 	err = ssi_debug_add_ctrl(ssi);
553 	if (err < 0)
554 		goto out2;
555 #endif
556 
557 	for_each_available_child_of_node(np, child) {
558 		if (!of_device_is_compatible(child, "ti,omap3-ssi-port"))
559 			continue;
560 
561 		childpdev = of_platform_device_create(child, NULL, &pd->dev);
562 		if (!childpdev) {
563 			err = -ENODEV;
564 			dev_err(&pd->dev, "failed to create ssi controller port\n");
565 			goto out3;
566 		}
567 	}
568 
569 	dev_info(&pd->dev, "ssi controller %d initialized (%d ports)!\n",
570 		ssi->id, num_ports);
571 	return err;
572 out3:
573 	device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
574 out2:
575 	ssi_remove_controller(ssi);
576 out1:
577 	platform_set_drvdata(pd, NULL);
578 	pm_runtime_disable(&pd->dev);
579 
580 	return err;
581 }
582 
583 static int ssi_remove(struct platform_device *pd)
584 {
585 	struct hsi_controller *ssi = platform_get_drvdata(pd);
586 
587 	/* cleanup of of_platform_populate() call */
588 	device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
589 
590 #ifdef CONFIG_DEBUG_FS
591 	ssi_debug_remove_ctrl(ssi);
592 #endif
593 	ssi_remove_controller(ssi);
594 	platform_set_drvdata(pd, NULL);
595 
596 	pm_runtime_disable(&pd->dev);
597 
598 	return 0;
599 }
600 
601 #ifdef CONFIG_PM
602 static int omap_ssi_runtime_suspend(struct device *dev)
603 {
604 	struct hsi_controller *ssi = dev_get_drvdata(dev);
605 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
606 
607 	dev_dbg(dev, "runtime suspend!\n");
608 
609 	if (omap_ssi->get_loss)
610 		omap_ssi->loss_count =
611 				omap_ssi->get_loss(ssi->device.parent);
612 
613 	return 0;
614 }
615 
616 static int omap_ssi_runtime_resume(struct device *dev)
617 {
618 	struct hsi_controller *ssi = dev_get_drvdata(dev);
619 	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
620 
621 	dev_dbg(dev, "runtime resume!\n");
622 
623 	if ((omap_ssi->get_loss) && (omap_ssi->loss_count ==
624 				omap_ssi->get_loss(ssi->device.parent)))
625 		return 0;
626 
627 	writel_relaxed(omap_ssi->gdd_gcr, omap_ssi->gdd + SSI_GDD_GCR_REG);
628 
629 	return 0;
630 }
631 
632 static const struct dev_pm_ops omap_ssi_pm_ops = {
633 	SET_RUNTIME_PM_OPS(omap_ssi_runtime_suspend, omap_ssi_runtime_resume,
634 		NULL)
635 };
636 
637 #define DEV_PM_OPS     (&omap_ssi_pm_ops)
638 #else
639 #define DEV_PM_OPS     NULL
640 #endif
641 
642 #ifdef CONFIG_OF
643 static const struct of_device_id omap_ssi_of_match[] = {
644 	{ .compatible = "ti,omap3-ssi", },
645 	{},
646 };
647 MODULE_DEVICE_TABLE(of, omap_ssi_of_match);
648 #else
649 #define omap_ssi_of_match NULL
650 #endif
651 
652 static struct platform_driver ssi_pdriver = {
653 	.probe = ssi_probe,
654 	.remove	= ssi_remove,
655 	.driver	= {
656 		.name	= "omap_ssi",
657 		.pm     = DEV_PM_OPS,
658 		.of_match_table = omap_ssi_of_match,
659 	},
660 };
661 
662 static int __init ssi_init(void) {
663 	int ret;
664 
665 	ret = platform_driver_register(&ssi_pdriver);
666 	if (ret)
667 		return ret;
668 
669 	return platform_driver_register(&ssi_port_pdriver);
670 }
671 module_init(ssi_init);
672 
673 static void __exit ssi_exit(void) {
674 	platform_driver_unregister(&ssi_port_pdriver);
675 	platform_driver_unregister(&ssi_pdriver);
676 }
677 module_exit(ssi_exit);
678 
679 MODULE_ALIAS("platform:omap_ssi");
680 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
681 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
682 MODULE_DESCRIPTION("Synchronous Serial Interface Driver");
683 MODULE_LICENSE("GPL v2");
684