xref: /linux/drivers/gpio/gpio-grgpio.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732) 
1 /*
2  * Driver for Aeroflex Gaisler GRGPIO General Purpose I/O cores.
3  *
4  * 2013 (c) Aeroflex Gaisler AB
5  *
6  * This driver supports the GRGPIO GPIO core available in the GRLIB VHDL
7  * IP core library.
8  *
9  * Full documentation of the GRGPIO core can be found here:
10  * http://www.gaisler.com/products/grlib/grip.pdf
11  *
12  * See "Documentation/devicetree/bindings/gpio/gpio-grgpio.txt" for
13  * information on open firmware properties.
14  *
15  * This program is free software; you can redistribute it and/or modify it
16  * under the terms of the GNU General Public License as published by the
17  * Free Software Foundation; either version 2 of the License, or (at your
18  * option) any later version.
19  *
20  * Contributors: Andreas Larsson <andreas@gaisler.com>
21  */
22 
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/spinlock.h>
27 #include <linux/io.h>
28 #include <linux/of.h>
29 #include <linux/of_gpio.h>
30 #include <linux/of_platform.h>
31 #include <linux/gpio.h>
32 #include <linux/slab.h>
33 #include <linux/err.h>
34 #include <linux/basic_mmio_gpio.h>
35 #include <linux/interrupt.h>
36 #include <linux/irq.h>
37 #include <linux/irqdomain.h>
38 
39 #define GRGPIO_MAX_NGPIO 32
40 
41 #define GRGPIO_DATA		0x00
42 #define GRGPIO_OUTPUT		0x04
43 #define GRGPIO_DIR		0x08
44 #define GRGPIO_IMASK		0x0c
45 #define GRGPIO_IPOL		0x10
46 #define GRGPIO_IEDGE		0x14
47 #define GRGPIO_BYPASS		0x18
48 #define GRGPIO_IMAP_BASE	0x20
49 
50 /* Structure for an irq of the core - called an underlying irq */
51 struct grgpio_uirq {
52 	u8 refcnt; /* Reference counter to manage requesting/freeing of uirq */
53 	u8 uirq; /* Underlying irq of the gpio driver */
54 };
55 
56 /*
57  * Structure for an irq of a gpio line handed out by this driver. The index is
58  * used to map to the corresponding underlying irq.
59  */
60 struct grgpio_lirq {
61 	s8 index; /* Index into struct grgpio_priv's uirqs, or -1 */
62 	u8 irq; /* irq for the gpio line */
63 };
64 
65 struct grgpio_priv {
66 	struct bgpio_chip bgc;
67 	void __iomem *regs;
68 	struct device *dev;
69 
70 	u32 imask; /* irq mask shadow register */
71 
72 	/*
73 	 * The grgpio core can have multiple "underlying" irqs. The gpio lines
74 	 * can be mapped to any one or none of these underlying irqs
75 	 * independently of each other. This driver sets up an irq domain and
76 	 * hands out separate irqs to each gpio line
77 	 */
78 	struct irq_domain *domain;
79 
80 	/*
81 	 * This array contains information on each underlying irq, each
82 	 * irq of the grgpio core itself.
83 	 */
84 	struct grgpio_uirq uirqs[GRGPIO_MAX_NGPIO];
85 
86 	/*
87 	 * This array contains information for each gpio line on the irqs
88 	 * obtains from this driver. An index value of -1 for a certain gpio
89 	 * line indicates that the line has no irq. Otherwise the index connects
90 	 * the irq to the underlying irq by pointing into the uirqs array.
91 	 */
92 	struct grgpio_lirq lirqs[GRGPIO_MAX_NGPIO];
93 };
94 
95 static inline struct grgpio_priv *grgpio_gc_to_priv(struct gpio_chip *gc)
96 {
97 	struct bgpio_chip *bgc = to_bgpio_chip(gc);
98 
99 	return container_of(bgc, struct grgpio_priv, bgc);
100 }
101 
102 static void grgpio_set_imask(struct grgpio_priv *priv, unsigned int offset,
103 			     int val)
104 {
105 	struct bgpio_chip *bgc = &priv->bgc;
106 	unsigned long mask = bgc->pin2mask(bgc, offset);
107 
108 	if (val)
109 		priv->imask |= mask;
110 	else
111 		priv->imask &= ~mask;
112 	bgc->write_reg(priv->regs + GRGPIO_IMASK, priv->imask);
113 }
114 
115 static int grgpio_to_irq(struct gpio_chip *gc, unsigned offset)
116 {
117 	struct grgpio_priv *priv = grgpio_gc_to_priv(gc);
118 
119 	if (offset >= gc->ngpio)
120 		return -ENXIO;
121 
122 	if (priv->lirqs[offset].index < 0)
123 		return -ENXIO;
124 
125 	return irq_create_mapping(priv->domain, offset);
126 }
127 
128 /* -------------------- IRQ chip functions -------------------- */
129 
130 static int grgpio_irq_set_type(struct irq_data *d, unsigned int type)
131 {
132 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
133 	unsigned long flags;
134 	u32 mask = BIT(d->hwirq);
135 	u32 ipol;
136 	u32 iedge;
137 	u32 pol;
138 	u32 edge;
139 
140 	switch (type) {
141 	case IRQ_TYPE_LEVEL_LOW:
142 		pol = 0;
143 		edge = 0;
144 		break;
145 	case IRQ_TYPE_LEVEL_HIGH:
146 		pol = mask;
147 		edge = 0;
148 		break;
149 	case IRQ_TYPE_EDGE_FALLING:
150 		pol = 0;
151 		edge = mask;
152 		break;
153 	case IRQ_TYPE_EDGE_RISING:
154 		pol = mask;
155 		edge = mask;
156 		break;
157 	default:
158 		return -EINVAL;
159 	}
160 
161 	spin_lock_irqsave(&priv->bgc.lock, flags);
162 
163 	ipol = priv->bgc.read_reg(priv->regs + GRGPIO_IPOL) & ~mask;
164 	iedge = priv->bgc.read_reg(priv->regs + GRGPIO_IEDGE) & ~mask;
165 
166 	priv->bgc.write_reg(priv->regs + GRGPIO_IPOL, ipol | pol);
167 	priv->bgc.write_reg(priv->regs + GRGPIO_IEDGE, iedge | edge);
168 
169 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
170 
171 	return 0;
172 }
173 
174 static void grgpio_irq_mask(struct irq_data *d)
175 {
176 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
177 	int offset = d->hwirq;
178 	unsigned long flags;
179 
180 	spin_lock_irqsave(&priv->bgc.lock, flags);
181 
182 	grgpio_set_imask(priv, offset, 0);
183 
184 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
185 }
186 
187 static void grgpio_irq_unmask(struct irq_data *d)
188 {
189 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
190 	int offset = d->hwirq;
191 	unsigned long flags;
192 
193 	spin_lock_irqsave(&priv->bgc.lock, flags);
194 
195 	grgpio_set_imask(priv, offset, 1);
196 
197 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
198 }
199 
200 static struct irq_chip grgpio_irq_chip = {
201 	.name			= "grgpio",
202 	.irq_mask		= grgpio_irq_mask,
203 	.irq_unmask		= grgpio_irq_unmask,
204 	.irq_set_type		= grgpio_irq_set_type,
205 };
206 
207 static irqreturn_t grgpio_irq_handler(int irq, void *dev)
208 {
209 	struct grgpio_priv *priv = dev;
210 	int ngpio = priv->bgc.gc.ngpio;
211 	unsigned long flags;
212 	int i;
213 	int match = 0;
214 
215 	spin_lock_irqsave(&priv->bgc.lock, flags);
216 
217 	/*
218 	 * For each gpio line, call its interrupt handler if it its underlying
219 	 * irq matches the current irq that is handled.
220 	 */
221 	for (i = 0; i < ngpio; i++) {
222 		struct grgpio_lirq *lirq = &priv->lirqs[i];
223 
224 		if (priv->imask & BIT(i) && lirq->index >= 0 &&
225 		    priv->uirqs[lirq->index].uirq == irq) {
226 			generic_handle_irq(lirq->irq);
227 			match = 1;
228 		}
229 	}
230 
231 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
232 
233 	if (!match)
234 		dev_warn(priv->dev, "No gpio line matched irq %d\n", irq);
235 
236 	return IRQ_HANDLED;
237 }
238 
239 /*
240  * This function will be called as a consequence of the call to
241  * irq_create_mapping in grgpio_to_irq
242  */
243 static int grgpio_irq_map(struct irq_domain *d, unsigned int irq,
244 			  irq_hw_number_t hwirq)
245 {
246 	struct grgpio_priv *priv = d->host_data;
247 	struct grgpio_lirq *lirq;
248 	struct grgpio_uirq *uirq;
249 	unsigned long flags;
250 	int offset = hwirq;
251 	int ret = 0;
252 
253 	if (!priv)
254 		return -EINVAL;
255 
256 	lirq = &priv->lirqs[offset];
257 	if (lirq->index < 0)
258 		return -EINVAL;
259 
260 	dev_dbg(priv->dev, "Mapping irq %d for gpio line %d\n",
261 		irq, offset);
262 
263 	spin_lock_irqsave(&priv->bgc.lock, flags);
264 
265 	/* Request underlying irq if not already requested */
266 	lirq->irq = irq;
267 	uirq = &priv->uirqs[lirq->index];
268 	if (uirq->refcnt == 0) {
269 		ret = request_irq(uirq->uirq, grgpio_irq_handler, 0,
270 				  dev_name(priv->dev), priv);
271 		if (ret) {
272 			dev_err(priv->dev,
273 				"Could not request underlying irq %d\n",
274 				uirq->uirq);
275 
276 			spin_unlock_irqrestore(&priv->bgc.lock, flags);
277 
278 			return ret;
279 		}
280 	}
281 	uirq->refcnt++;
282 
283 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
284 
285 	/* Setup irq  */
286 	irq_set_chip_data(irq, priv);
287 	irq_set_chip_and_handler(irq, &grgpio_irq_chip,
288 				 handle_simple_irq);
289 	irq_set_noprobe(irq);
290 
291 	return ret;
292 }
293 
294 static void grgpio_irq_unmap(struct irq_domain *d, unsigned int irq)
295 {
296 	struct grgpio_priv *priv = d->host_data;
297 	int index;
298 	struct grgpio_lirq *lirq;
299 	struct grgpio_uirq *uirq;
300 	unsigned long flags;
301 	int ngpio = priv->bgc.gc.ngpio;
302 	int i;
303 
304 	irq_set_chip_and_handler(irq, NULL, NULL);
305 	irq_set_chip_data(irq, NULL);
306 
307 	spin_lock_irqsave(&priv->bgc.lock, flags);
308 
309 	/* Free underlying irq if last user unmapped */
310 	index = -1;
311 	for (i = 0; i < ngpio; i++) {
312 		lirq = &priv->lirqs[i];
313 		if (lirq->irq == irq) {
314 			grgpio_set_imask(priv, i, 0);
315 			lirq->irq = 0;
316 			index = lirq->index;
317 			break;
318 		}
319 	}
320 	WARN_ON(index < 0);
321 
322 	if (index >= 0) {
323 		uirq = &priv->uirqs[lirq->index];
324 		uirq->refcnt--;
325 		if (uirq->refcnt == 0)
326 			free_irq(uirq->uirq, priv);
327 	}
328 
329 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
330 }
331 
332 static const struct irq_domain_ops grgpio_irq_domain_ops = {
333 	.map	= grgpio_irq_map,
334 	.unmap	= grgpio_irq_unmap,
335 };
336 
337 /* ------------------------------------------------------------ */
338 
339 static int grgpio_probe(struct platform_device *ofdev)
340 {
341 	struct device_node *np = ofdev->dev.of_node;
342 	void  __iomem *regs;
343 	struct gpio_chip *gc;
344 	struct bgpio_chip *bgc;
345 	struct grgpio_priv *priv;
346 	struct resource *res;
347 	int err;
348 	u32 prop;
349 	s32 *irqmap;
350 	int size;
351 	int i;
352 
353 	priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
354 	if (!priv)
355 		return -ENOMEM;
356 
357 	res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
358 	regs = devm_ioremap_resource(&ofdev->dev, res);
359 	if (IS_ERR(regs))
360 		return PTR_ERR(regs);
361 
362 	bgc = &priv->bgc;
363 	err = bgpio_init(bgc, &ofdev->dev, 4, regs + GRGPIO_DATA,
364 			 regs + GRGPIO_OUTPUT, NULL, regs + GRGPIO_DIR, NULL,
365 			 BGPIOF_BIG_ENDIAN_BYTE_ORDER);
366 	if (err) {
367 		dev_err(&ofdev->dev, "bgpio_init() failed\n");
368 		return err;
369 	}
370 
371 	priv->regs = regs;
372 	priv->imask = bgc->read_reg(regs + GRGPIO_IMASK);
373 	priv->dev = &ofdev->dev;
374 
375 	gc = &bgc->gc;
376 	gc->of_node = np;
377 	gc->owner = THIS_MODULE;
378 	gc->to_irq = grgpio_to_irq;
379 	gc->label = np->full_name;
380 	gc->base = -1;
381 
382 	err = of_property_read_u32(np, "nbits", &prop);
383 	if (err || prop <= 0 || prop > GRGPIO_MAX_NGPIO) {
384 		gc->ngpio = GRGPIO_MAX_NGPIO;
385 		dev_dbg(&ofdev->dev,
386 			"No or invalid nbits property: assume %d\n", gc->ngpio);
387 	} else {
388 		gc->ngpio = prop;
389 	}
390 
391 	/*
392 	 * The irqmap contains the index values indicating which underlying irq,
393 	 * if anyone, is connected to that line
394 	 */
395 	irqmap = (s32 *)of_get_property(np, "irqmap", &size);
396 	if (irqmap) {
397 		if (size < gc->ngpio) {
398 			dev_err(&ofdev->dev,
399 				"irqmap shorter than ngpio (%d < %d)\n",
400 				size, gc->ngpio);
401 			return -EINVAL;
402 		}
403 
404 		priv->domain = irq_domain_add_linear(np, gc->ngpio,
405 						     &grgpio_irq_domain_ops,
406 						     priv);
407 		if (!priv->domain) {
408 			dev_err(&ofdev->dev, "Could not add irq domain\n");
409 			return -EINVAL;
410 		}
411 
412 		for (i = 0; i < gc->ngpio; i++) {
413 			struct grgpio_lirq *lirq;
414 			int ret;
415 
416 			lirq = &priv->lirqs[i];
417 			lirq->index = irqmap[i];
418 
419 			if (lirq->index < 0)
420 				continue;
421 
422 			ret = platform_get_irq(ofdev, lirq->index);
423 			if (ret <= 0) {
424 				/*
425 				 * Continue without irq functionality for that
426 				 * gpio line
427 				 */
428 				dev_err(priv->dev,
429 					"Failed to get irq for offset %d\n", i);
430 				continue;
431 			}
432 			priv->uirqs[lirq->index].uirq = ret;
433 		}
434 	}
435 
436 	platform_set_drvdata(ofdev, priv);
437 
438 	err = gpiochip_add(gc);
439 	if (err) {
440 		dev_err(&ofdev->dev, "Could not add gpiochip\n");
441 		if (priv->domain)
442 			irq_domain_remove(priv->domain);
443 		return err;
444 	}
445 
446 	dev_info(&ofdev->dev, "regs=0x%p, base=%d, ngpio=%d, irqs=%s\n",
447 		 priv->regs, gc->base, gc->ngpio, priv->domain ? "on" : "off");
448 
449 	return 0;
450 }
451 
452 static int grgpio_remove(struct platform_device *ofdev)
453 {
454 	struct grgpio_priv *priv = platform_get_drvdata(ofdev);
455 	unsigned long flags;
456 	int i;
457 	int ret = 0;
458 
459 	spin_lock_irqsave(&priv->bgc.lock, flags);
460 
461 	if (priv->domain) {
462 		for (i = 0; i < GRGPIO_MAX_NGPIO; i++) {
463 			if (priv->uirqs[i].refcnt != 0) {
464 				ret = -EBUSY;
465 				goto out;
466 			}
467 		}
468 	}
469 
470 	gpiochip_remove(&priv->bgc.gc);
471 
472 	if (priv->domain)
473 		irq_domain_remove(priv->domain);
474 
475 out:
476 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
477 
478 	return ret;
479 }
480 
481 static const struct of_device_id grgpio_match[] = {
482 	{.name = "GAISLER_GPIO"},
483 	{.name = "01_01a"},
484 	{},
485 };
486 
487 MODULE_DEVICE_TABLE(of, grgpio_match);
488 
489 static struct platform_driver grgpio_driver = {
490 	.driver = {
491 		.name = "grgpio",
492 		.of_match_table = grgpio_match,
493 	},
494 	.probe = grgpio_probe,
495 	.remove = grgpio_remove,
496 };
497 module_platform_driver(grgpio_driver);
498 
499 MODULE_AUTHOR("Aeroflex Gaisler AB.");
500 MODULE_DESCRIPTION("Driver for Aeroflex Gaisler GRGPIO");
501 MODULE_LICENSE("GPL");
502