xref: /openbmc/linux/drivers/vlynq/vlynq.c (revision 2fa5ebe3)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2006, 2007 Eugene Konev <ejka@openwrt.org>
4  *
5  * Parts of the VLYNQ specification can be found here:
6  * http://www.ti.com/litv/pdf/sprue36a
7  */
8 
9 #include <linux/init.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13 #include <linux/device.h>
14 #include <linux/module.h>
15 #include <linux/errno.h>
16 #include <linux/platform_device.h>
17 #include <linux/interrupt.h>
18 #include <linux/delay.h>
19 #include <linux/io.h>
20 #include <linux/slab.h>
21 #include <linux/irq.h>
22 
23 #include <linux/vlynq.h>
24 
25 #define VLYNQ_CTRL_PM_ENABLE		0x80000000
26 #define VLYNQ_CTRL_CLOCK_INT		0x00008000
27 #define VLYNQ_CTRL_CLOCK_DIV(x)		(((x) & 7) << 16)
28 #define VLYNQ_CTRL_INT_LOCAL		0x00004000
29 #define VLYNQ_CTRL_INT_ENABLE		0x00002000
30 #define VLYNQ_CTRL_INT_VECTOR(x)	(((x) & 0x1f) << 8)
31 #define VLYNQ_CTRL_INT2CFG		0x00000080
32 #define VLYNQ_CTRL_RESET		0x00000001
33 
34 #define VLYNQ_CTRL_CLOCK_MASK          (0x7 << 16)
35 
36 #define VLYNQ_INT_OFFSET		0x00000014
37 #define VLYNQ_REMOTE_OFFSET		0x00000080
38 
39 #define VLYNQ_STATUS_LINK		0x00000001
40 #define VLYNQ_STATUS_LERROR		0x00000080
41 #define VLYNQ_STATUS_RERROR		0x00000100
42 
43 #define VINT_ENABLE			0x00000100
44 #define VINT_TYPE_EDGE			0x00000080
45 #define VINT_LEVEL_LOW			0x00000040
46 #define VINT_VECTOR(x)			((x) & 0x1f)
47 #define VINT_OFFSET(irq)		(8 * ((irq) % 4))
48 
49 #define VLYNQ_AUTONEGO_V2		0x00010000
50 
51 struct vlynq_regs {
52 	u32 revision;
53 	u32 control;
54 	u32 status;
55 	u32 int_prio;
56 	u32 int_status;
57 	u32 int_pending;
58 	u32 int_ptr;
59 	u32 tx_offset;
60 	struct vlynq_mapping rx_mapping[4];
61 	u32 chip;
62 	u32 autonego;
63 	u32 unused[6];
64 	u32 int_device[8];
65 };
66 
67 #ifdef CONFIG_VLYNQ_DEBUG
68 static void vlynq_dump_regs(struct vlynq_device *dev)
69 {
70 	int i;
71 
72 	printk(KERN_DEBUG "VLYNQ local=%p remote=%p\n",
73 			dev->local, dev->remote);
74 	for (i = 0; i < 32; i++) {
75 		printk(KERN_DEBUG "VLYNQ: local %d: %08x\n",
76 			i + 1, ((u32 *)dev->local)[i]);
77 		printk(KERN_DEBUG "VLYNQ: remote %d: %08x\n",
78 			i + 1, ((u32 *)dev->remote)[i]);
79 	}
80 }
81 
82 static void vlynq_dump_mem(u32 *base, int count)
83 {
84 	int i;
85 
86 	for (i = 0; i < (count + 3) / 4; i++) {
87 		if (i % 4 == 0)
88 			printk(KERN_DEBUG "\nMEM[0x%04x]:", i * 4);
89 		printk(KERN_DEBUG " 0x%08x", *(base + i));
90 	}
91 	printk(KERN_DEBUG "\n");
92 }
93 #endif
94 
95 /* Check the VLYNQ link status with a given device */
96 static int vlynq_linked(struct vlynq_device *dev)
97 {
98 	int i;
99 
100 	for (i = 0; i < 100; i++)
101 		if (readl(&dev->local->status) & VLYNQ_STATUS_LINK)
102 			return 1;
103 		else
104 			cpu_relax();
105 
106 	return 0;
107 }
108 
109 static void vlynq_reset(struct vlynq_device *dev)
110 {
111 	writel(readl(&dev->local->control) | VLYNQ_CTRL_RESET,
112 			&dev->local->control);
113 
114 	/* Wait for the devices to finish resetting */
115 	msleep(5);
116 
117 	/* Remove reset bit */
118 	writel(readl(&dev->local->control) & ~VLYNQ_CTRL_RESET,
119 			&dev->local->control);
120 
121 	/* Give some time for the devices to settle */
122 	msleep(5);
123 }
124 
125 static void vlynq_irq_unmask(struct irq_data *d)
126 {
127 	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
128 	int virq;
129 	u32 val;
130 
131 	BUG_ON(!dev);
132 	virq = d->irq - dev->irq_start;
133 	val = readl(&dev->remote->int_device[virq >> 2]);
134 	val |= (VINT_ENABLE | virq) << VINT_OFFSET(virq);
135 	writel(val, &dev->remote->int_device[virq >> 2]);
136 }
137 
138 static void vlynq_irq_mask(struct irq_data *d)
139 {
140 	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
141 	int virq;
142 	u32 val;
143 
144 	BUG_ON(!dev);
145 	virq = d->irq - dev->irq_start;
146 	val = readl(&dev->remote->int_device[virq >> 2]);
147 	val &= ~(VINT_ENABLE << VINT_OFFSET(virq));
148 	writel(val, &dev->remote->int_device[virq >> 2]);
149 }
150 
151 static int vlynq_irq_type(struct irq_data *d, unsigned int flow_type)
152 {
153 	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
154 	int virq;
155 	u32 val;
156 
157 	BUG_ON(!dev);
158 	virq = d->irq - dev->irq_start;
159 	val = readl(&dev->remote->int_device[virq >> 2]);
160 	switch (flow_type & IRQ_TYPE_SENSE_MASK) {
161 	case IRQ_TYPE_EDGE_RISING:
162 	case IRQ_TYPE_EDGE_FALLING:
163 	case IRQ_TYPE_EDGE_BOTH:
164 		val |= VINT_TYPE_EDGE << VINT_OFFSET(virq);
165 		val &= ~(VINT_LEVEL_LOW << VINT_OFFSET(virq));
166 		break;
167 	case IRQ_TYPE_LEVEL_HIGH:
168 		val &= ~(VINT_TYPE_EDGE << VINT_OFFSET(virq));
169 		val &= ~(VINT_LEVEL_LOW << VINT_OFFSET(virq));
170 		break;
171 	case IRQ_TYPE_LEVEL_LOW:
172 		val &= ~(VINT_TYPE_EDGE << VINT_OFFSET(virq));
173 		val |= VINT_LEVEL_LOW << VINT_OFFSET(virq);
174 		break;
175 	default:
176 		return -EINVAL;
177 	}
178 	writel(val, &dev->remote->int_device[virq >> 2]);
179 	return 0;
180 }
181 
182 static void vlynq_local_ack(struct irq_data *d)
183 {
184 	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
185 	u32 status = readl(&dev->local->status);
186 
187 	pr_debug("%s: local status: 0x%08x\n",
188 		       dev_name(&dev->dev), status);
189 	writel(status, &dev->local->status);
190 }
191 
192 static void vlynq_remote_ack(struct irq_data *d)
193 {
194 	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
195 	u32 status = readl(&dev->remote->status);
196 
197 	pr_debug("%s: remote status: 0x%08x\n",
198 		       dev_name(&dev->dev), status);
199 	writel(status, &dev->remote->status);
200 }
201 
202 static irqreturn_t vlynq_irq(int irq, void *dev_id)
203 {
204 	struct vlynq_device *dev = dev_id;
205 	u32 status;
206 	int virq = 0;
207 
208 	status = readl(&dev->local->int_status);
209 	writel(status, &dev->local->int_status);
210 
211 	if (unlikely(!status))
212 		spurious_interrupt();
213 
214 	while (status) {
215 		if (status & 1)
216 			do_IRQ(dev->irq_start + virq);
217 		status >>= 1;
218 		virq++;
219 	}
220 
221 	return IRQ_HANDLED;
222 }
223 
224 static struct irq_chip vlynq_irq_chip = {
225 	.name = "vlynq",
226 	.irq_unmask = vlynq_irq_unmask,
227 	.irq_mask = vlynq_irq_mask,
228 	.irq_set_type = vlynq_irq_type,
229 };
230 
231 static struct irq_chip vlynq_local_chip = {
232 	.name = "vlynq local error",
233 	.irq_unmask = vlynq_irq_unmask,
234 	.irq_mask = vlynq_irq_mask,
235 	.irq_ack = vlynq_local_ack,
236 };
237 
238 static struct irq_chip vlynq_remote_chip = {
239 	.name = "vlynq local error",
240 	.irq_unmask = vlynq_irq_unmask,
241 	.irq_mask = vlynq_irq_mask,
242 	.irq_ack = vlynq_remote_ack,
243 };
244 
245 static int vlynq_setup_irq(struct vlynq_device *dev)
246 {
247 	u32 val;
248 	int i, virq;
249 
250 	if (dev->local_irq == dev->remote_irq) {
251 		printk(KERN_ERR
252 		       "%s: local vlynq irq should be different from remote\n",
253 		       dev_name(&dev->dev));
254 		return -EINVAL;
255 	}
256 
257 	/* Clear local and remote error bits */
258 	writel(readl(&dev->local->status), &dev->local->status);
259 	writel(readl(&dev->remote->status), &dev->remote->status);
260 
261 	/* Now setup interrupts */
262 	val = VLYNQ_CTRL_INT_VECTOR(dev->local_irq);
263 	val |= VLYNQ_CTRL_INT_ENABLE | VLYNQ_CTRL_INT_LOCAL |
264 		VLYNQ_CTRL_INT2CFG;
265 	val |= readl(&dev->local->control);
266 	writel(VLYNQ_INT_OFFSET, &dev->local->int_ptr);
267 	writel(val, &dev->local->control);
268 
269 	val = VLYNQ_CTRL_INT_VECTOR(dev->remote_irq);
270 	val |= VLYNQ_CTRL_INT_ENABLE;
271 	val |= readl(&dev->remote->control);
272 	writel(VLYNQ_INT_OFFSET, &dev->remote->int_ptr);
273 	writel(val, &dev->remote->int_ptr);
274 	writel(val, &dev->remote->control);
275 
276 	for (i = dev->irq_start; i <= dev->irq_end; i++) {
277 		virq = i - dev->irq_start;
278 		if (virq == dev->local_irq) {
279 			irq_set_chip_and_handler(i, &vlynq_local_chip,
280 						 handle_level_irq);
281 			irq_set_chip_data(i, dev);
282 		} else if (virq == dev->remote_irq) {
283 			irq_set_chip_and_handler(i, &vlynq_remote_chip,
284 						 handle_level_irq);
285 			irq_set_chip_data(i, dev);
286 		} else {
287 			irq_set_chip_and_handler(i, &vlynq_irq_chip,
288 						 handle_simple_irq);
289 			irq_set_chip_data(i, dev);
290 			writel(0, &dev->remote->int_device[virq >> 2]);
291 		}
292 	}
293 
294 	if (request_irq(dev->irq, vlynq_irq, IRQF_SHARED, "vlynq", dev)) {
295 		printk(KERN_ERR "%s: request_irq failed\n",
296 					dev_name(&dev->dev));
297 		return -EAGAIN;
298 	}
299 
300 	return 0;
301 }
302 
303 static void vlynq_device_release(struct device *dev)
304 {
305 	struct vlynq_device *vdev = to_vlynq_device(dev);
306 	kfree(vdev);
307 }
308 
309 static int vlynq_device_match(struct device *dev,
310 			      struct device_driver *drv)
311 {
312 	struct vlynq_device *vdev = to_vlynq_device(dev);
313 	struct vlynq_driver *vdrv = to_vlynq_driver(drv);
314 	struct vlynq_device_id *ids = vdrv->id_table;
315 
316 	while (ids->id) {
317 		if (ids->id == vdev->dev_id) {
318 			vdev->divisor = ids->divisor;
319 			vlynq_set_drvdata(vdev, ids);
320 			printk(KERN_INFO "Driver found for VLYNQ "
321 				"device: %08x\n", vdev->dev_id);
322 			return 1;
323 		}
324 		printk(KERN_DEBUG "Not using the %08x VLYNQ device's driver"
325 			" for VLYNQ device: %08x\n", ids->id, vdev->dev_id);
326 		ids++;
327 	}
328 	return 0;
329 }
330 
331 static int vlynq_device_probe(struct device *dev)
332 {
333 	struct vlynq_device *vdev = to_vlynq_device(dev);
334 	struct vlynq_driver *drv = to_vlynq_driver(dev->driver);
335 	struct vlynq_device_id *id = vlynq_get_drvdata(vdev);
336 	int result = -ENODEV;
337 
338 	if (drv->probe)
339 		result = drv->probe(vdev, id);
340 	if (result)
341 		put_device(dev);
342 	return result;
343 }
344 
345 static void vlynq_device_remove(struct device *dev)
346 {
347 	struct vlynq_driver *drv = to_vlynq_driver(dev->driver);
348 
349 	if (drv->remove)
350 		drv->remove(to_vlynq_device(dev));
351 }
352 
353 int __vlynq_register_driver(struct vlynq_driver *driver, struct module *owner)
354 {
355 	driver->driver.name = driver->name;
356 	driver->driver.bus = &vlynq_bus_type;
357 	return driver_register(&driver->driver);
358 }
359 EXPORT_SYMBOL(__vlynq_register_driver);
360 
361 void vlynq_unregister_driver(struct vlynq_driver *driver)
362 {
363 	driver_unregister(&driver->driver);
364 }
365 EXPORT_SYMBOL(vlynq_unregister_driver);
366 
367 /*
368  * A VLYNQ remote device can clock the VLYNQ bus master
369  * using a dedicated clock line. In that case, both the
370  * remove device and the bus master should have the same
371  * serial clock dividers configured. Iterate through the
372  * 8 possible dividers until we actually link with the
373  * device.
374  */
375 static int __vlynq_try_remote(struct vlynq_device *dev)
376 {
377 	int i;
378 
379 	vlynq_reset(dev);
380 	for (i = dev->dev_id ? vlynq_rdiv2 : vlynq_rdiv8; dev->dev_id ?
381 			i <= vlynq_rdiv8 : i >= vlynq_rdiv2;
382 		dev->dev_id ? i++ : i--) {
383 
384 		if (!vlynq_linked(dev))
385 			break;
386 
387 		writel((readl(&dev->remote->control) &
388 				~VLYNQ_CTRL_CLOCK_MASK) |
389 				VLYNQ_CTRL_CLOCK_INT |
390 				VLYNQ_CTRL_CLOCK_DIV(i - vlynq_rdiv1),
391 				&dev->remote->control);
392 		writel((readl(&dev->local->control)
393 				& ~(VLYNQ_CTRL_CLOCK_INT |
394 				VLYNQ_CTRL_CLOCK_MASK)) |
395 				VLYNQ_CTRL_CLOCK_DIV(i - vlynq_rdiv1),
396 				&dev->local->control);
397 
398 		if (vlynq_linked(dev)) {
399 			printk(KERN_DEBUG
400 				"%s: using remote clock divisor %d\n",
401 				dev_name(&dev->dev), i - vlynq_rdiv1 + 1);
402 			dev->divisor = i;
403 			return 0;
404 		} else {
405 			vlynq_reset(dev);
406 		}
407 	}
408 
409 	return -ENODEV;
410 }
411 
412 /*
413  * A VLYNQ remote device can be clocked by the VLYNQ bus
414  * master using a dedicated clock line. In that case, only
415  * the bus master configures the serial clock divider.
416  * Iterate through the 8 possible dividers until we
417  * actually get a link with the device.
418  */
419 static int __vlynq_try_local(struct vlynq_device *dev)
420 {
421 	int i;
422 
423 	vlynq_reset(dev);
424 
425 	for (i = dev->dev_id ? vlynq_ldiv2 : vlynq_ldiv8; dev->dev_id ?
426 			i <= vlynq_ldiv8 : i >= vlynq_ldiv2;
427 		dev->dev_id ? i++ : i--) {
428 
429 		writel((readl(&dev->local->control) &
430 				~VLYNQ_CTRL_CLOCK_MASK) |
431 				VLYNQ_CTRL_CLOCK_INT |
432 				VLYNQ_CTRL_CLOCK_DIV(i - vlynq_ldiv1),
433 				&dev->local->control);
434 
435 		if (vlynq_linked(dev)) {
436 			printk(KERN_DEBUG
437 				"%s: using local clock divisor %d\n",
438 				dev_name(&dev->dev), i - vlynq_ldiv1 + 1);
439 			dev->divisor = i;
440 			return 0;
441 		} else {
442 			vlynq_reset(dev);
443 		}
444 	}
445 
446 	return -ENODEV;
447 }
448 
449 /*
450  * When using external clocking method, serial clock
451  * is supplied by an external oscillator, therefore we
452  * should mask the local clock bit in the clock control
453  * register for both the bus master and the remote device.
454  */
455 static int __vlynq_try_external(struct vlynq_device *dev)
456 {
457 	vlynq_reset(dev);
458 	if (!vlynq_linked(dev))
459 		return -ENODEV;
460 
461 	writel((readl(&dev->remote->control) &
462 			~VLYNQ_CTRL_CLOCK_INT),
463 			&dev->remote->control);
464 
465 	writel((readl(&dev->local->control) &
466 			~VLYNQ_CTRL_CLOCK_INT),
467 			&dev->local->control);
468 
469 	if (vlynq_linked(dev)) {
470 		printk(KERN_DEBUG "%s: using external clock\n",
471 			dev_name(&dev->dev));
472 			dev->divisor = vlynq_div_external;
473 		return 0;
474 	}
475 
476 	return -ENODEV;
477 }
478 
479 static int __vlynq_enable_device(struct vlynq_device *dev)
480 {
481 	int result;
482 	struct plat_vlynq_ops *ops = dev->dev.platform_data;
483 
484 	result = ops->on(dev);
485 	if (result)
486 		return result;
487 
488 	switch (dev->divisor) {
489 	case vlynq_div_external:
490 	case vlynq_div_auto:
491 		/* When the device is brought from reset it should have clock
492 		 * generation negotiated by hardware.
493 		 * Check which device is generating clocks and perform setup
494 		 * accordingly */
495 		if (vlynq_linked(dev) && readl(&dev->remote->control) &
496 		   VLYNQ_CTRL_CLOCK_INT) {
497 			if (!__vlynq_try_remote(dev) ||
498 				!__vlynq_try_local(dev)  ||
499 				!__vlynq_try_external(dev))
500 				return 0;
501 		} else {
502 			if (!__vlynq_try_external(dev) ||
503 				!__vlynq_try_local(dev)    ||
504 				!__vlynq_try_remote(dev))
505 				return 0;
506 		}
507 		break;
508 	case vlynq_ldiv1:
509 	case vlynq_ldiv2:
510 	case vlynq_ldiv3:
511 	case vlynq_ldiv4:
512 	case vlynq_ldiv5:
513 	case vlynq_ldiv6:
514 	case vlynq_ldiv7:
515 	case vlynq_ldiv8:
516 		writel(VLYNQ_CTRL_CLOCK_INT |
517 			VLYNQ_CTRL_CLOCK_DIV(dev->divisor -
518 			vlynq_ldiv1), &dev->local->control);
519 		writel(0, &dev->remote->control);
520 		if (vlynq_linked(dev)) {
521 			printk(KERN_DEBUG
522 				"%s: using local clock divisor %d\n",
523 				dev_name(&dev->dev),
524 				dev->divisor - vlynq_ldiv1 + 1);
525 			return 0;
526 		}
527 		break;
528 	case vlynq_rdiv1:
529 	case vlynq_rdiv2:
530 	case vlynq_rdiv3:
531 	case vlynq_rdiv4:
532 	case vlynq_rdiv5:
533 	case vlynq_rdiv6:
534 	case vlynq_rdiv7:
535 	case vlynq_rdiv8:
536 		writel(0, &dev->local->control);
537 		writel(VLYNQ_CTRL_CLOCK_INT |
538 			VLYNQ_CTRL_CLOCK_DIV(dev->divisor -
539 			vlynq_rdiv1), &dev->remote->control);
540 		if (vlynq_linked(dev)) {
541 			printk(KERN_DEBUG
542 				"%s: using remote clock divisor %d\n",
543 				dev_name(&dev->dev),
544 				dev->divisor - vlynq_rdiv1 + 1);
545 			return 0;
546 		}
547 		break;
548 	}
549 
550 	ops->off(dev);
551 	return -ENODEV;
552 }
553 
554 int vlynq_enable_device(struct vlynq_device *dev)
555 {
556 	struct plat_vlynq_ops *ops = dev->dev.platform_data;
557 	int result = -ENODEV;
558 
559 	result = __vlynq_enable_device(dev);
560 	if (result)
561 		return result;
562 
563 	result = vlynq_setup_irq(dev);
564 	if (result)
565 		ops->off(dev);
566 
567 	dev->enabled = !result;
568 	return result;
569 }
570 EXPORT_SYMBOL(vlynq_enable_device);
571 
572 
573 void vlynq_disable_device(struct vlynq_device *dev)
574 {
575 	struct plat_vlynq_ops *ops = dev->dev.platform_data;
576 
577 	dev->enabled = 0;
578 	free_irq(dev->irq, dev);
579 	ops->off(dev);
580 }
581 EXPORT_SYMBOL(vlynq_disable_device);
582 
583 int vlynq_set_local_mapping(struct vlynq_device *dev, u32 tx_offset,
584 			    struct vlynq_mapping *mapping)
585 {
586 	int i;
587 
588 	if (!dev->enabled)
589 		return -ENXIO;
590 
591 	writel(tx_offset, &dev->local->tx_offset);
592 	for (i = 0; i < 4; i++) {
593 		writel(mapping[i].offset, &dev->local->rx_mapping[i].offset);
594 		writel(mapping[i].size, &dev->local->rx_mapping[i].size);
595 	}
596 	return 0;
597 }
598 EXPORT_SYMBOL(vlynq_set_local_mapping);
599 
600 int vlynq_set_remote_mapping(struct vlynq_device *dev, u32 tx_offset,
601 			     struct vlynq_mapping *mapping)
602 {
603 	int i;
604 
605 	if (!dev->enabled)
606 		return -ENXIO;
607 
608 	writel(tx_offset, &dev->remote->tx_offset);
609 	for (i = 0; i < 4; i++) {
610 		writel(mapping[i].offset, &dev->remote->rx_mapping[i].offset);
611 		writel(mapping[i].size, &dev->remote->rx_mapping[i].size);
612 	}
613 	return 0;
614 }
615 EXPORT_SYMBOL(vlynq_set_remote_mapping);
616 
617 int vlynq_set_local_irq(struct vlynq_device *dev, int virq)
618 {
619 	int irq = dev->irq_start + virq;
620 	if (dev->enabled)
621 		return -EBUSY;
622 
623 	if ((irq < dev->irq_start) || (irq > dev->irq_end))
624 		return -EINVAL;
625 
626 	if (virq == dev->remote_irq)
627 		return -EINVAL;
628 
629 	dev->local_irq = virq;
630 
631 	return 0;
632 }
633 EXPORT_SYMBOL(vlynq_set_local_irq);
634 
635 int vlynq_set_remote_irq(struct vlynq_device *dev, int virq)
636 {
637 	int irq = dev->irq_start + virq;
638 	if (dev->enabled)
639 		return -EBUSY;
640 
641 	if ((irq < dev->irq_start) || (irq > dev->irq_end))
642 		return -EINVAL;
643 
644 	if (virq == dev->local_irq)
645 		return -EINVAL;
646 
647 	dev->remote_irq = virq;
648 
649 	return 0;
650 }
651 EXPORT_SYMBOL(vlynq_set_remote_irq);
652 
653 static int vlynq_probe(struct platform_device *pdev)
654 {
655 	struct vlynq_device *dev;
656 	struct resource *regs_res, *mem_res, *irq_res;
657 	int len, result;
658 
659 	regs_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
660 	if (!regs_res)
661 		return -ENODEV;
662 
663 	mem_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem");
664 	if (!mem_res)
665 		return -ENODEV;
666 
667 	irq_res = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "devirq");
668 	if (!irq_res)
669 		return -ENODEV;
670 
671 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
672 	if (!dev) {
673 		printk(KERN_ERR
674 		       "vlynq: failed to allocate device structure\n");
675 		return -ENOMEM;
676 	}
677 
678 	dev->id = pdev->id;
679 	dev->dev.bus = &vlynq_bus_type;
680 	dev->dev.parent = &pdev->dev;
681 	dev_set_name(&dev->dev, "vlynq%d", dev->id);
682 	dev->dev.platform_data = pdev->dev.platform_data;
683 	dev->dev.release = vlynq_device_release;
684 
685 	dev->regs_start = regs_res->start;
686 	dev->regs_end = regs_res->end;
687 	dev->mem_start = mem_res->start;
688 	dev->mem_end = mem_res->end;
689 
690 	len = resource_size(regs_res);
691 	if (!request_mem_region(regs_res->start, len, dev_name(&dev->dev))) {
692 		printk(KERN_ERR "%s: Can't request vlynq registers\n",
693 		       dev_name(&dev->dev));
694 		result = -ENXIO;
695 		goto fail_request;
696 	}
697 
698 	dev->local = ioremap(regs_res->start, len);
699 	if (!dev->local) {
700 		printk(KERN_ERR "%s: Can't remap vlynq registers\n",
701 		       dev_name(&dev->dev));
702 		result = -ENXIO;
703 		goto fail_remap;
704 	}
705 
706 	dev->remote = (struct vlynq_regs *)((void *)dev->local +
707 					    VLYNQ_REMOTE_OFFSET);
708 
709 	dev->irq = platform_get_irq_byname(pdev, "irq");
710 	dev->irq_start = irq_res->start;
711 	dev->irq_end = irq_res->end;
712 	dev->local_irq = dev->irq_end - dev->irq_start;
713 	dev->remote_irq = dev->local_irq - 1;
714 
715 	if (device_register(&dev->dev))
716 		goto fail_register;
717 	platform_set_drvdata(pdev, dev);
718 
719 	printk(KERN_INFO "%s: regs 0x%p, irq %d, mem 0x%p\n",
720 	       dev_name(&dev->dev), (void *)dev->regs_start, dev->irq,
721 	       (void *)dev->mem_start);
722 
723 	dev->dev_id = 0;
724 	dev->divisor = vlynq_div_auto;
725 	result = __vlynq_enable_device(dev);
726 	if (result == 0) {
727 		dev->dev_id = readl(&dev->remote->chip);
728 		((struct plat_vlynq_ops *)(dev->dev.platform_data))->off(dev);
729 	}
730 	if (dev->dev_id)
731 		printk(KERN_INFO "Found a VLYNQ device: %08x\n", dev->dev_id);
732 
733 	return 0;
734 
735 fail_register:
736 	iounmap(dev->local);
737 fail_remap:
738 fail_request:
739 	release_mem_region(regs_res->start, len);
740 	kfree(dev);
741 	return result;
742 }
743 
744 static int vlynq_remove(struct platform_device *pdev)
745 {
746 	struct vlynq_device *dev = platform_get_drvdata(pdev);
747 
748 	device_unregister(&dev->dev);
749 	iounmap(dev->local);
750 	release_mem_region(dev->regs_start,
751 			   dev->regs_end - dev->regs_start + 1);
752 
753 	kfree(dev);
754 
755 	return 0;
756 }
757 
758 static struct platform_driver vlynq_platform_driver = {
759 	.driver.name = "vlynq",
760 	.probe = vlynq_probe,
761 	.remove = vlynq_remove,
762 };
763 
764 struct bus_type vlynq_bus_type = {
765 	.name = "vlynq",
766 	.match = vlynq_device_match,
767 	.probe = vlynq_device_probe,
768 	.remove = vlynq_device_remove,
769 };
770 EXPORT_SYMBOL(vlynq_bus_type);
771 
772 static int vlynq_init(void)
773 {
774 	int res = 0;
775 
776 	res = bus_register(&vlynq_bus_type);
777 	if (res)
778 		goto fail_bus;
779 
780 	res = platform_driver_register(&vlynq_platform_driver);
781 	if (res)
782 		goto fail_platform;
783 
784 	return 0;
785 
786 fail_platform:
787 	bus_unregister(&vlynq_bus_type);
788 fail_bus:
789 	return res;
790 }
791 
792 static void vlynq_exit(void)
793 {
794 	platform_driver_unregister(&vlynq_platform_driver);
795 	bus_unregister(&vlynq_bus_type);
796 }
797 
798 module_init(vlynq_init);
799 module_exit(vlynq_exit);
800