xref: /linux/drivers/gpio/gpio-brcmstb.c (revision 68a052239fc4b351e961f698b824f7654a346091)
1 // SPDX-License-Identifier: GPL-2.0-only
2 // Copyright (C) 2015-2017 Broadcom
3 
4 #include <linux/bitops.h>
5 #include <linux/gpio/driver.h>
6 #include <linux/gpio/generic.h>
7 #include <linux/of.h>
8 #include <linux/module.h>
9 #include <linux/irqdomain.h>
10 #include <linux/irqchip/chained_irq.h>
11 #include <linux/interrupt.h>
12 #include <linux/platform_device.h>
13 #include <linux/string_choices.h>
14 
15 enum gio_reg_index {
16 	GIO_REG_ODEN = 0,
17 	GIO_REG_DATA,
18 	GIO_REG_IODIR,
19 	GIO_REG_EC,
20 	GIO_REG_EI,
21 	GIO_REG_MASK,
22 	GIO_REG_LEVEL,
23 	GIO_REG_STAT,
24 	NUMBER_OF_GIO_REGISTERS
25 };
26 
27 #define GIO_BANK_SIZE           (NUMBER_OF_GIO_REGISTERS * sizeof(u32))
28 #define GIO_BANK_OFF(bank, off)	(((bank) * GIO_BANK_SIZE) + (off * sizeof(u32)))
29 #define GIO_ODEN(bank)          GIO_BANK_OFF(bank, GIO_REG_ODEN)
30 #define GIO_DATA(bank)          GIO_BANK_OFF(bank, GIO_REG_DATA)
31 #define GIO_IODIR(bank)         GIO_BANK_OFF(bank, GIO_REG_IODIR)
32 #define GIO_EC(bank)            GIO_BANK_OFF(bank, GIO_REG_EC)
33 #define GIO_EI(bank)            GIO_BANK_OFF(bank, GIO_REG_EI)
34 #define GIO_MASK(bank)          GIO_BANK_OFF(bank, GIO_REG_MASK)
35 #define GIO_LEVEL(bank)         GIO_BANK_OFF(bank, GIO_REG_LEVEL)
36 #define GIO_STAT(bank)          GIO_BANK_OFF(bank, GIO_REG_STAT)
37 
38 struct brcmstb_gpio_bank {
39 	struct list_head node;
40 	int id;
41 	struct gpio_generic_chip chip;
42 	struct brcmstb_gpio_priv *parent_priv;
43 	u32 width;
44 	u32 wake_active;
45 	u32 saved_regs[GIO_REG_STAT]; /* Don't save and restore GIO_REG_STAT */
46 };
47 
48 struct brcmstb_gpio_priv {
49 	struct list_head bank_list;
50 	void __iomem *reg_base;
51 	struct platform_device *pdev;
52 	struct irq_domain *irq_domain;
53 	struct irq_chip irq_chip;
54 	int parent_irq;
55 	int num_gpios;
56 	int parent_wake_irq;
57 };
58 
59 #define MAX_GPIO_PER_BANK       32
60 #define GPIO_BANK(gpio)         ((gpio) >> 5)
61 /* assumes MAX_GPIO_PER_BANK is a multiple of 2 */
62 #define GPIO_BIT(gpio)          ((gpio) & (MAX_GPIO_PER_BANK - 1))
63 
64 static inline struct brcmstb_gpio_priv *
65 brcmstb_gpio_gc_to_priv(struct gpio_chip *gc)
66 {
67 	struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
68 	return bank->parent_priv;
69 }
70 
71 static unsigned long
72 __brcmstb_gpio_get_active_irqs(struct brcmstb_gpio_bank *bank)
73 {
74 	void __iomem *reg_base = bank->parent_priv->reg_base;
75 
76 	return gpio_generic_read_reg(&bank->chip, reg_base + GIO_STAT(bank->id)) &
77 	       gpio_generic_read_reg(&bank->chip, reg_base + GIO_MASK(bank->id));
78 }
79 
80 static unsigned long
81 brcmstb_gpio_get_active_irqs(struct brcmstb_gpio_bank *bank)
82 {
83 	unsigned long status;
84 
85 	guard(gpio_generic_lock_irqsave)(&bank->chip);
86 
87 	status = __brcmstb_gpio_get_active_irqs(bank);
88 
89 	return status;
90 }
91 
92 static int brcmstb_gpio_hwirq_to_offset(irq_hw_number_t hwirq,
93 					struct brcmstb_gpio_bank *bank)
94 {
95 	return hwirq - bank->chip.gc.offset;
96 }
97 
98 static void brcmstb_gpio_set_imask(struct brcmstb_gpio_bank *bank,
99 		unsigned int hwirq, bool enable)
100 {
101 	struct brcmstb_gpio_priv *priv = bank->parent_priv;
102 	u32 mask = BIT(brcmstb_gpio_hwirq_to_offset(hwirq, bank));
103 	u32 imask;
104 
105 	guard(gpio_generic_lock_irqsave)(&bank->chip);
106 
107 	imask = gpio_generic_read_reg(&bank->chip,
108 				      priv->reg_base + GIO_MASK(bank->id));
109 	if (enable)
110 		imask |= mask;
111 	else
112 		imask &= ~mask;
113 	gpio_generic_write_reg(&bank->chip,
114 			       priv->reg_base + GIO_MASK(bank->id), imask);
115 }
116 
117 static int brcmstb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
118 {
119 	struct brcmstb_gpio_priv *priv = brcmstb_gpio_gc_to_priv(gc);
120 	/* gc_offset is relative to this gpio_chip; want real offset */
121 	int hwirq = offset + gc->offset;
122 
123 	if (hwirq >= priv->num_gpios)
124 		return -ENXIO;
125 	return irq_create_mapping(priv->irq_domain, hwirq);
126 }
127 
128 /* -------------------- IRQ chip functions -------------------- */
129 
130 static void brcmstb_gpio_irq_mask(struct irq_data *d)
131 {
132 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
133 	struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
134 
135 	brcmstb_gpio_set_imask(bank, d->hwirq, false);
136 }
137 
138 static void brcmstb_gpio_irq_unmask(struct irq_data *d)
139 {
140 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
141 	struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
142 
143 	brcmstb_gpio_set_imask(bank, d->hwirq, true);
144 }
145 
146 static void brcmstb_gpio_irq_ack(struct irq_data *d)
147 {
148 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
149 	struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
150 	struct brcmstb_gpio_priv *priv = bank->parent_priv;
151 	u32 mask = BIT(brcmstb_gpio_hwirq_to_offset(d->hwirq, bank));
152 
153 	gpio_generic_write_reg(&bank->chip,
154 			       priv->reg_base + GIO_STAT(bank->id), mask);
155 }
156 
157 static int brcmstb_gpio_irq_set_type(struct irq_data *d, unsigned int type)
158 {
159 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
160 	struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
161 	struct brcmstb_gpio_priv *priv = bank->parent_priv;
162 	u32 mask = BIT(brcmstb_gpio_hwirq_to_offset(d->hwirq, bank));
163 	u32 edge_insensitive, iedge_insensitive;
164 	u32 edge_config, iedge_config;
165 	u32 level, ilevel;
166 
167 	switch (type) {
168 	case IRQ_TYPE_LEVEL_LOW:
169 		level = mask;
170 		edge_config = 0;
171 		edge_insensitive = 0;
172 		break;
173 	case IRQ_TYPE_LEVEL_HIGH:
174 		level = mask;
175 		edge_config = mask;
176 		edge_insensitive = 0;
177 		break;
178 	case IRQ_TYPE_EDGE_FALLING:
179 		level = 0;
180 		edge_config = 0;
181 		edge_insensitive = 0;
182 		break;
183 	case IRQ_TYPE_EDGE_RISING:
184 		level = 0;
185 		edge_config = mask;
186 		edge_insensitive = 0;
187 		break;
188 	case IRQ_TYPE_EDGE_BOTH:
189 		level = 0;
190 		edge_config = 0;  /* don't care, but want known value */
191 		edge_insensitive = mask;
192 		break;
193 	default:
194 		return -EINVAL;
195 	}
196 
197 	guard(gpio_generic_lock_irqsave)(&bank->chip);
198 
199 	iedge_config = gpio_generic_read_reg(&bank->chip,
200 				priv->reg_base + GIO_EC(bank->id)) & ~mask;
201 	iedge_insensitive = gpio_generic_read_reg(&bank->chip,
202 				priv->reg_base + GIO_EI(bank->id)) & ~mask;
203 	ilevel = gpio_generic_read_reg(&bank->chip,
204 				priv->reg_base + GIO_LEVEL(bank->id)) & ~mask;
205 
206 	gpio_generic_write_reg(&bank->chip,
207 			       priv->reg_base + GIO_EC(bank->id),
208 			       iedge_config | edge_config);
209 	gpio_generic_write_reg(&bank->chip,
210 			       priv->reg_base + GIO_EI(bank->id),
211 			       iedge_insensitive | edge_insensitive);
212 	gpio_generic_write_reg(&bank->chip,
213 			       priv->reg_base + GIO_LEVEL(bank->id),
214 			       ilevel | level);
215 
216 	return 0;
217 }
218 
219 static int brcmstb_gpio_priv_set_wake(struct brcmstb_gpio_priv *priv,
220 		unsigned int enable)
221 {
222 	int ret = 0;
223 
224 	if (enable)
225 		ret = enable_irq_wake(priv->parent_wake_irq);
226 	else
227 		ret = disable_irq_wake(priv->parent_wake_irq);
228 	if (ret)
229 		dev_err(&priv->pdev->dev, "failed to %s wake-up interrupt\n",
230 			str_enable_disable(enable));
231 	return ret;
232 }
233 
234 static int brcmstb_gpio_irq_set_wake(struct irq_data *d, unsigned int enable)
235 {
236 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
237 	struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
238 	struct brcmstb_gpio_priv *priv = bank->parent_priv;
239 	u32 mask = BIT(brcmstb_gpio_hwirq_to_offset(d->hwirq, bank));
240 
241 	/*
242 	 * Do not do anything specific for now, suspend/resume callbacks will
243 	 * configure the interrupt mask appropriately
244 	 */
245 	if (enable)
246 		bank->wake_active |= mask;
247 	else
248 		bank->wake_active &= ~mask;
249 
250 	return brcmstb_gpio_priv_set_wake(priv, enable);
251 }
252 
253 static irqreturn_t brcmstb_gpio_wake_irq_handler(int irq, void *data)
254 {
255 	struct brcmstb_gpio_priv *priv = data;
256 
257 	if (!priv || irq != priv->parent_wake_irq)
258 		return IRQ_NONE;
259 
260 	/* Nothing to do */
261 	return IRQ_HANDLED;
262 }
263 
264 static void brcmstb_gpio_irq_bank_handler(struct brcmstb_gpio_bank *bank)
265 {
266 	struct brcmstb_gpio_priv *priv = bank->parent_priv;
267 	struct irq_domain *domain = priv->irq_domain;
268 	int hwbase = bank->chip.gc.offset;
269 	unsigned long status;
270 
271 	while ((status = brcmstb_gpio_get_active_irqs(bank))) {
272 		unsigned int offset;
273 
274 		for_each_set_bit(offset, &status, 32) {
275 			if (offset >= bank->width)
276 				dev_warn(&priv->pdev->dev,
277 					 "IRQ for invalid GPIO (bank=%d, offset=%d)\n",
278 					 bank->id, offset);
279 			generic_handle_domain_irq(domain, hwbase + offset);
280 		}
281 	}
282 }
283 
284 /* Each UPG GIO block has one IRQ for all banks */
285 static void brcmstb_gpio_irq_handler(struct irq_desc *desc)
286 {
287 	struct brcmstb_gpio_priv *priv = irq_desc_get_handler_data(desc);
288 	struct irq_chip *chip = irq_desc_get_chip(desc);
289 	struct brcmstb_gpio_bank *bank;
290 
291 	/* Interrupts weren't properly cleared during probe */
292 	BUG_ON(!priv || !chip);
293 
294 	chained_irq_enter(chip, desc);
295 	list_for_each_entry(bank, &priv->bank_list, node)
296 		brcmstb_gpio_irq_bank_handler(bank);
297 	chained_irq_exit(chip, desc);
298 }
299 
300 static struct brcmstb_gpio_bank *brcmstb_gpio_hwirq_to_bank(
301 		struct brcmstb_gpio_priv *priv, irq_hw_number_t hwirq)
302 {
303 	struct brcmstb_gpio_bank *bank;
304 	int i = 0;
305 
306 	/* banks are in descending order */
307 	list_for_each_entry_reverse(bank, &priv->bank_list, node) {
308 		i += bank->chip.gc.ngpio;
309 		if (hwirq < i)
310 			return bank;
311 	}
312 	return NULL;
313 }
314 
315 /*
316  * This lock class tells lockdep that GPIO irqs are in a different
317  * category than their parents, so it won't report false recursion.
318  */
319 static struct lock_class_key brcmstb_gpio_irq_lock_class;
320 static struct lock_class_key brcmstb_gpio_irq_request_class;
321 
322 
323 static int brcmstb_gpio_irq_map(struct irq_domain *d, unsigned int irq,
324 		irq_hw_number_t hwirq)
325 {
326 	struct brcmstb_gpio_priv *priv = d->host_data;
327 	struct brcmstb_gpio_bank *bank =
328 		brcmstb_gpio_hwirq_to_bank(priv, hwirq);
329 	struct platform_device *pdev = priv->pdev;
330 	int ret;
331 
332 	if (!bank)
333 		return -EINVAL;
334 
335 	dev_dbg(&pdev->dev, "Mapping irq %d for gpio line %d (bank %d)\n",
336 		irq, (int)hwirq, bank->id);
337 	ret = irq_set_chip_data(irq, &bank->chip.gc);
338 	if (ret < 0)
339 		return ret;
340 	irq_set_lockdep_class(irq, &brcmstb_gpio_irq_lock_class,
341 			      &brcmstb_gpio_irq_request_class);
342 	irq_set_chip_and_handler(irq, &priv->irq_chip, handle_level_irq);
343 	irq_set_noprobe(irq);
344 	return 0;
345 }
346 
347 static void brcmstb_gpio_irq_unmap(struct irq_domain *d, unsigned int irq)
348 {
349 	irq_set_chip_and_handler(irq, NULL, NULL);
350 	irq_set_chip_data(irq, NULL);
351 }
352 
353 static const struct irq_domain_ops brcmstb_gpio_irq_domain_ops = {
354 	.map = brcmstb_gpio_irq_map,
355 	.unmap = brcmstb_gpio_irq_unmap,
356 	.xlate = irq_domain_xlate_twocell,
357 };
358 
359 /* Make sure that the number of banks matches up between properties */
360 static int brcmstb_gpio_sanity_check_banks(struct device *dev,
361 		struct device_node *np, struct resource *res)
362 {
363 	int res_num_banks = resource_size(res) / GIO_BANK_SIZE;
364 	int num_banks =
365 		of_property_count_u32_elems(np, "brcm,gpio-bank-widths");
366 
367 	if (res_num_banks != num_banks) {
368 		dev_err(dev, "Mismatch in banks: res had %d, bank-widths had %d\n",
369 				res_num_banks, num_banks);
370 		return -EINVAL;
371 	} else {
372 		return 0;
373 	}
374 }
375 
376 static void brcmstb_gpio_remove(struct platform_device *pdev)
377 {
378 	struct brcmstb_gpio_priv *priv = platform_get_drvdata(pdev);
379 	struct brcmstb_gpio_bank *bank;
380 	int offset, virq;
381 
382 	if (priv->parent_irq > 0)
383 		irq_set_chained_handler_and_data(priv->parent_irq, NULL, NULL);
384 
385 	/* Remove all IRQ mappings and delete the domain */
386 	if (priv->irq_domain) {
387 		for (offset = 0; offset < priv->num_gpios; offset++) {
388 			virq = irq_find_mapping(priv->irq_domain, offset);
389 			irq_dispose_mapping(virq);
390 		}
391 		irq_domain_remove(priv->irq_domain);
392 	}
393 
394 	/*
395 	 * You can lose return values below, but we report all errors, and it's
396 	 * more important to actually perform all of the steps.
397 	 */
398 	list_for_each_entry(bank, &priv->bank_list, node)
399 		gpiochip_remove(&bank->chip.gc);
400 }
401 
402 static int brcmstb_gpio_of_xlate(struct gpio_chip *gc,
403 		const struct of_phandle_args *gpiospec, u32 *flags)
404 {
405 	struct brcmstb_gpio_priv *priv = brcmstb_gpio_gc_to_priv(gc);
406 	struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
407 	int offset;
408 
409 	if (gc->of_gpio_n_cells != 2) {
410 		WARN_ON(1);
411 		return -EINVAL;
412 	}
413 
414 	if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
415 		return -EINVAL;
416 
417 	offset = gpiospec->args[0] - bank->chip.gc.offset;
418 	if (offset >= gc->ngpio || offset < 0)
419 		return -EINVAL;
420 
421 	if (unlikely(offset >= bank->width)) {
422 		dev_warn_ratelimited(&priv->pdev->dev,
423 			"Received request for invalid GPIO offset %d\n",
424 			gpiospec->args[0]);
425 	}
426 
427 	if (flags)
428 		*flags = gpiospec->args[1];
429 
430 	return offset;
431 }
432 
433 /* priv->parent_irq and priv->num_gpios must be set before calling */
434 static int brcmstb_gpio_irq_setup(struct platform_device *pdev,
435 		struct brcmstb_gpio_priv *priv)
436 {
437 	struct device *dev = &pdev->dev;
438 	struct device_node *np = dev->of_node;
439 	int err;
440 
441 	priv->irq_domain = irq_domain_create_linear(dev_fwnode(dev), priv->num_gpios,
442 						    &brcmstb_gpio_irq_domain_ops, priv);
443 	if (!priv->irq_domain) {
444 		dev_err(dev, "Couldn't allocate IRQ domain\n");
445 		return -ENXIO;
446 	}
447 
448 	if (of_property_read_bool(np, "wakeup-source")) {
449 		priv->parent_wake_irq = platform_get_irq(pdev, 1);
450 		if (priv->parent_wake_irq < 0) {
451 			priv->parent_wake_irq = 0;
452 			dev_warn(dev,
453 				"Couldn't get wake IRQ - GPIOs will not be able to wake from sleep");
454 		} else {
455 			/*
456 			 * Set wakeup capability so we can process boot-time
457 			 * "wakeups" (e.g., from S5 cold boot)
458 			 */
459 			device_set_wakeup_capable(dev, true);
460 			device_wakeup_enable(dev);
461 			err = devm_request_irq(dev, priv->parent_wake_irq,
462 					       brcmstb_gpio_wake_irq_handler,
463 					       IRQF_SHARED,
464 					       "brcmstb-gpio-wake", priv);
465 
466 			if (err < 0) {
467 				dev_err(dev, "Couldn't request wake IRQ");
468 				goto out_free_domain;
469 			}
470 		}
471 	}
472 
473 	priv->irq_chip.name = dev_name(dev);
474 	priv->irq_chip.irq_disable = brcmstb_gpio_irq_mask;
475 	priv->irq_chip.irq_mask = brcmstb_gpio_irq_mask;
476 	priv->irq_chip.irq_unmask = brcmstb_gpio_irq_unmask;
477 	priv->irq_chip.irq_ack = brcmstb_gpio_irq_ack;
478 	priv->irq_chip.irq_set_type = brcmstb_gpio_irq_set_type;
479 
480 	if (priv->parent_wake_irq)
481 		priv->irq_chip.irq_set_wake = brcmstb_gpio_irq_set_wake;
482 
483 	irq_set_chained_handler_and_data(priv->parent_irq,
484 					 brcmstb_gpio_irq_handler, priv);
485 	irq_set_status_flags(priv->parent_irq, IRQ_DISABLE_UNLAZY);
486 
487 	return 0;
488 
489 out_free_domain:
490 	irq_domain_remove(priv->irq_domain);
491 
492 	return err;
493 }
494 
495 static void brcmstb_gpio_bank_save(struct brcmstb_gpio_priv *priv,
496 				   struct brcmstb_gpio_bank *bank)
497 {
498 	unsigned int i;
499 
500 	for (i = 0; i < GIO_REG_STAT; i++)
501 		bank->saved_regs[i] = gpio_generic_read_reg(&bank->chip,
502 					priv->reg_base + GIO_BANK_OFF(bank->id, i));
503 }
504 
505 static void brcmstb_gpio_quiesce(struct device *dev, bool save)
506 {
507 	struct brcmstb_gpio_priv *priv = dev_get_drvdata(dev);
508 	struct brcmstb_gpio_bank *bank;
509 	u32 imask;
510 
511 	/* disable non-wake interrupt */
512 	if (priv->parent_irq >= 0)
513 		disable_irq(priv->parent_irq);
514 
515 	list_for_each_entry(bank, &priv->bank_list, node) {
516 		if (save)
517 			brcmstb_gpio_bank_save(priv, bank);
518 
519 		/* Unmask GPIOs which have been flagged as wake-up sources */
520 		if (priv->parent_wake_irq)
521 			imask = bank->wake_active;
522 		else
523 			imask = 0;
524 		gpio_generic_write_reg(&bank->chip,
525 				       priv->reg_base + GIO_MASK(bank->id),
526 				       imask);
527 	}
528 }
529 
530 static void brcmstb_gpio_shutdown(struct platform_device *pdev)
531 {
532 	/* Enable GPIO for S5 cold boot */
533 	brcmstb_gpio_quiesce(&pdev->dev, false);
534 }
535 
536 #ifdef CONFIG_PM_SLEEP
537 static void brcmstb_gpio_bank_restore(struct brcmstb_gpio_priv *priv,
538 				      struct brcmstb_gpio_bank *bank)
539 {
540 	unsigned int i;
541 
542 	for (i = 0; i < GIO_REG_STAT; i++)
543 		gpio_generic_write_reg(&bank->chip,
544 				       priv->reg_base + GIO_BANK_OFF(bank->id, i),
545 				       bank->saved_regs[i]);
546 }
547 
548 static int brcmstb_gpio_suspend(struct device *dev)
549 {
550 	brcmstb_gpio_quiesce(dev, true);
551 	return 0;
552 }
553 
554 static int brcmstb_gpio_resume(struct device *dev)
555 {
556 	struct brcmstb_gpio_priv *priv = dev_get_drvdata(dev);
557 	struct brcmstb_gpio_bank *bank;
558 	bool need_wakeup_event = false;
559 
560 	list_for_each_entry(bank, &priv->bank_list, node) {
561 		need_wakeup_event |= !!__brcmstb_gpio_get_active_irqs(bank);
562 		brcmstb_gpio_bank_restore(priv, bank);
563 	}
564 
565 	if (priv->parent_wake_irq && need_wakeup_event)
566 		pm_wakeup_event(dev, 0);
567 
568 	/* enable non-wake interrupt */
569 	if (priv->parent_irq >= 0)
570 		enable_irq(priv->parent_irq);
571 
572 	return 0;
573 }
574 
575 #else
576 #define brcmstb_gpio_suspend	NULL
577 #define brcmstb_gpio_resume	NULL
578 #endif /* CONFIG_PM_SLEEP */
579 
580 static const struct dev_pm_ops brcmstb_gpio_pm_ops = {
581 	.suspend_noirq	= brcmstb_gpio_suspend,
582 	.resume_noirq = brcmstb_gpio_resume,
583 };
584 
585 static int brcmstb_gpio_probe(struct platform_device *pdev)
586 {
587 	struct gpio_generic_chip_config config;
588 	struct device *dev = &pdev->dev;
589 	struct device_node *np = dev->of_node;
590 	void __iomem *reg_base;
591 	struct brcmstb_gpio_priv *priv;
592 	struct resource *res;
593 	u32 bank_width;
594 	int num_banks = 0;
595 	int num_gpios = 0;
596 	int err;
597 	unsigned long flags = 0;
598 	bool need_wakeup_event = false;
599 
600 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
601 	if (!priv)
602 		return -ENOMEM;
603 	platform_set_drvdata(pdev, priv);
604 	INIT_LIST_HEAD(&priv->bank_list);
605 
606 	reg_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
607 	if (IS_ERR(reg_base))
608 		return PTR_ERR(reg_base);
609 
610 	priv->reg_base = reg_base;
611 	priv->pdev = pdev;
612 
613 	if (of_property_read_bool(np, "interrupt-controller")) {
614 		priv->parent_irq = platform_get_irq(pdev, 0);
615 		if (priv->parent_irq <= 0)
616 			return -ENOENT;
617 	} else {
618 		priv->parent_irq = -ENOENT;
619 	}
620 
621 	if (brcmstb_gpio_sanity_check_banks(dev, np, res))
622 		return -EINVAL;
623 
624 	/*
625 	 * MIPS endianness is configured by boot strap, which also reverses all
626 	 * bus endianness (i.e., big-endian CPU + big endian bus ==> native
627 	 * endian I/O).
628 	 *
629 	 * Other architectures (e.g., ARM) either do not support big endian, or
630 	 * else leave I/O in little endian mode.
631 	 */
632 #if defined(CONFIG_MIPS) && defined(__BIG_ENDIAN)
633 	flags = GPIO_GENERIC_BIG_ENDIAN_BYTE_ORDER;
634 #endif
635 
636 	of_property_for_each_u32(np, "brcm,gpio-bank-widths", bank_width) {
637 		struct brcmstb_gpio_bank *bank;
638 		struct gpio_chip *gc;
639 
640 		/*
641 		 * If bank_width is 0, then there is an empty bank in the
642 		 * register block. Special handling for this case.
643 		 */
644 		if (bank_width == 0) {
645 			dev_dbg(dev, "Width 0 found: Empty bank @ %d\n",
646 				num_banks);
647 			num_banks++;
648 			num_gpios += MAX_GPIO_PER_BANK;
649 			continue;
650 		}
651 
652 		bank = devm_kzalloc(dev, sizeof(*bank), GFP_KERNEL);
653 		if (!bank) {
654 			err = -ENOMEM;
655 			goto fail;
656 		}
657 
658 		bank->parent_priv = priv;
659 		bank->id = num_banks;
660 		if (bank_width <= 0 || bank_width > MAX_GPIO_PER_BANK) {
661 			dev_err(dev, "Invalid bank width %d\n", bank_width);
662 			err = -EINVAL;
663 			goto fail;
664 		} else {
665 			bank->width = bank_width;
666 		}
667 
668 		gc = &bank->chip.gc;
669 
670 		/*
671 		 * Regs are 4 bytes wide, have data reg, no set/clear regs,
672 		 * and direction bits have 0 = output and 1 = input
673 		 */
674 
675 		config = (struct gpio_generic_chip_config) {
676 			.dev = dev,
677 			.sz = 4,
678 			.dat = reg_base + GIO_DATA(bank->id),
679 			.dirin = reg_base + GIO_IODIR(bank->id),
680 			.flags = flags,
681 		};
682 
683 		err = gpio_generic_chip_init(&bank->chip, &config);
684 		if (err) {
685 			dev_err(dev, "failed to initialize generic GPIO chip\n");
686 			goto fail;
687 		}
688 
689 		gc->owner = THIS_MODULE;
690 		gc->label = devm_kasprintf(dev, GFP_KERNEL, "%pOF", np);
691 		if (!gc->label) {
692 			err = -ENOMEM;
693 			goto fail;
694 		}
695 		gc->of_gpio_n_cells = 2;
696 		gc->of_xlate = brcmstb_gpio_of_xlate;
697 		/* not all ngpio lines are valid, will use bank width later */
698 		gc->ngpio = MAX_GPIO_PER_BANK;
699 		gc->offset = bank->id * MAX_GPIO_PER_BANK;
700 		gc->request = gpiochip_generic_request;
701 		gc->free = gpiochip_generic_free;
702 		if (priv->parent_irq > 0)
703 			gc->to_irq = brcmstb_gpio_to_irq;
704 
705 		/*
706 		 * Mask all interrupts by default, since wakeup interrupts may
707 		 * be retained from S5 cold boot
708 		 */
709 		need_wakeup_event |= !!__brcmstb_gpio_get_active_irqs(bank);
710 		gpio_generic_write_reg(&bank->chip,
711 				       reg_base + GIO_MASK(bank->id), 0);
712 
713 		err = gpiochip_add_data(gc, bank);
714 		if (err) {
715 			dev_err(dev, "Could not add gpiochip for bank %d\n",
716 					bank->id);
717 			goto fail;
718 		}
719 		num_gpios += gc->ngpio;
720 
721 		dev_dbg(dev, "bank=%d, base=%d, ngpio=%d, width=%d\n", bank->id,
722 			gc->base, gc->ngpio, bank->width);
723 
724 		/* Everything looks good, so add bank to list */
725 		list_add(&bank->node, &priv->bank_list);
726 
727 		num_banks++;
728 	}
729 
730 	priv->num_gpios = num_gpios;
731 	if (priv->parent_irq > 0) {
732 		err = brcmstb_gpio_irq_setup(pdev, priv);
733 		if (err)
734 			goto fail;
735 	}
736 
737 	if (priv->parent_wake_irq && need_wakeup_event)
738 		pm_wakeup_event(dev, 0);
739 
740 	return 0;
741 
742 fail:
743 	(void) brcmstb_gpio_remove(pdev);
744 	return err;
745 }
746 
747 static const struct of_device_id brcmstb_gpio_of_match[] = {
748 	{ .compatible = "brcm,brcmstb-gpio" },
749 	{},
750 };
751 
752 MODULE_DEVICE_TABLE(of, brcmstb_gpio_of_match);
753 
754 static struct platform_driver brcmstb_gpio_driver = {
755 	.driver = {
756 		.name = "brcmstb-gpio",
757 		.of_match_table = brcmstb_gpio_of_match,
758 		.pm = &brcmstb_gpio_pm_ops,
759 	},
760 	.probe = brcmstb_gpio_probe,
761 	.remove = brcmstb_gpio_remove,
762 	.shutdown = brcmstb_gpio_shutdown,
763 };
764 module_platform_driver(brcmstb_gpio_driver);
765 
766 MODULE_AUTHOR("Gregory Fong");
767 MODULE_DESCRIPTION("Driver for Broadcom BRCMSTB SoC UPG GPIO");
768 MODULE_LICENSE("GPL v2");
769