xref: /openbmc/linux/drivers/gpio/gpio-grgpio.c (revision 6774def6) 
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 	unsigned long flags;
108 
109 	spin_lock_irqsave(&bgc->lock, flags);
110 
111 	if (val)
112 		priv->imask |= mask;
113 	else
114 		priv->imask &= ~mask;
115 	bgc->write_reg(priv->regs + GRGPIO_IMASK, priv->imask);
116 
117 	spin_unlock_irqrestore(&bgc->lock, flags);
118 }
119 
120 static int grgpio_to_irq(struct gpio_chip *gc, unsigned offset)
121 {
122 	struct grgpio_priv *priv = grgpio_gc_to_priv(gc);
123 
124 	if (offset > gc->ngpio)
125 		return -ENXIO;
126 
127 	if (priv->lirqs[offset].index < 0)
128 		return -ENXIO;
129 
130 	return irq_create_mapping(priv->domain, offset);
131 }
132 
133 /* -------------------- IRQ chip functions -------------------- */
134 
135 static int grgpio_irq_set_type(struct irq_data *d, unsigned int type)
136 {
137 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
138 	unsigned long flags;
139 	u32 mask = BIT(d->hwirq);
140 	u32 ipol;
141 	u32 iedge;
142 	u32 pol;
143 	u32 edge;
144 
145 	switch (type) {
146 	case IRQ_TYPE_LEVEL_LOW:
147 		pol = 0;
148 		edge = 0;
149 		break;
150 	case IRQ_TYPE_LEVEL_HIGH:
151 		pol = mask;
152 		edge = 0;
153 		break;
154 	case IRQ_TYPE_EDGE_FALLING:
155 		pol = 0;
156 		edge = mask;
157 		break;
158 	case IRQ_TYPE_EDGE_RISING:
159 		pol = mask;
160 		edge = mask;
161 		break;
162 	default:
163 		return -EINVAL;
164 	}
165 
166 	spin_lock_irqsave(&priv->bgc.lock, flags);
167 
168 	ipol = priv->bgc.read_reg(priv->regs + GRGPIO_IPOL) & ~mask;
169 	iedge = priv->bgc.read_reg(priv->regs + GRGPIO_IEDGE) & ~mask;
170 
171 	priv->bgc.write_reg(priv->regs + GRGPIO_IPOL, ipol | pol);
172 	priv->bgc.write_reg(priv->regs + GRGPIO_IEDGE, iedge | edge);
173 
174 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
175 
176 	return 0;
177 }
178 
179 static void grgpio_irq_mask(struct irq_data *d)
180 {
181 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
182 	int offset = d->hwirq;
183 
184 	grgpio_set_imask(priv, offset, 0);
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 
192 	grgpio_set_imask(priv, offset, 1);
193 }
194 
195 static struct irq_chip grgpio_irq_chip = {
196 	.name			= "grgpio",
197 	.irq_mask		= grgpio_irq_mask,
198 	.irq_unmask		= grgpio_irq_unmask,
199 	.irq_set_type		= grgpio_irq_set_type,
200 };
201 
202 static irqreturn_t grgpio_irq_handler(int irq, void *dev)
203 {
204 	struct grgpio_priv *priv = dev;
205 	int ngpio = priv->bgc.gc.ngpio;
206 	unsigned long flags;
207 	int i;
208 	int match = 0;
209 
210 	spin_lock_irqsave(&priv->bgc.lock, flags);
211 
212 	/*
213 	 * For each gpio line, call its interrupt handler if it its underlying
214 	 * irq matches the current irq that is handled.
215 	 */
216 	for (i = 0; i < ngpio; i++) {
217 		struct grgpio_lirq *lirq = &priv->lirqs[i];
218 
219 		if (priv->imask & BIT(i) && lirq->index >= 0 &&
220 		    priv->uirqs[lirq->index].uirq == irq) {
221 			generic_handle_irq(lirq->irq);
222 			match = 1;
223 		}
224 	}
225 
226 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
227 
228 	if (!match)
229 		dev_warn(priv->dev, "No gpio line matched irq %d\n", irq);
230 
231 	return IRQ_HANDLED;
232 }
233 
234 /*
235  * This function will be called as a consequence of the call to
236  * irq_create_mapping in grgpio_to_irq
237  */
238 static int grgpio_irq_map(struct irq_domain *d, unsigned int irq,
239 			  irq_hw_number_t hwirq)
240 {
241 	struct grgpio_priv *priv = d->host_data;
242 	struct grgpio_lirq *lirq;
243 	struct grgpio_uirq *uirq;
244 	unsigned long flags;
245 	int offset = hwirq;
246 	int ret = 0;
247 
248 	if (!priv)
249 		return -EINVAL;
250 
251 	lirq = &priv->lirqs[offset];
252 	if (lirq->index < 0)
253 		return -EINVAL;
254 
255 	dev_dbg(priv->dev, "Mapping irq %d for gpio line %d\n",
256 		irq, offset);
257 
258 	spin_lock_irqsave(&priv->bgc.lock, flags);
259 
260 	/* Request underlying irq if not already requested */
261 	lirq->irq = irq;
262 	uirq = &priv->uirqs[lirq->index];
263 	if (uirq->refcnt == 0) {
264 		ret = request_irq(uirq->uirq, grgpio_irq_handler, 0,
265 				  dev_name(priv->dev), priv);
266 		if (ret) {
267 			dev_err(priv->dev,
268 				"Could not request underlying irq %d\n",
269 				uirq->uirq);
270 
271 			spin_unlock_irqrestore(&priv->bgc.lock, flags);
272 
273 			return ret;
274 		}
275 	}
276 	uirq->refcnt++;
277 
278 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
279 
280 	/* Setup irq  */
281 	irq_set_chip_data(irq, priv);
282 	irq_set_chip_and_handler(irq, &grgpio_irq_chip,
283 				 handle_simple_irq);
284 	irq_clear_status_flags(irq, IRQ_NOREQUEST);
285 #ifdef CONFIG_ARM
286 	set_irq_flags(irq, IRQF_VALID);
287 #else
288 	irq_set_noprobe(irq);
289 #endif
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 #ifdef CONFIG_ARM
305 	set_irq_flags(irq, 0);
306 #endif
307 	irq_set_chip_and_handler(irq, NULL, NULL);
308 	irq_set_chip_data(irq, NULL);
309 
310 	spin_lock_irqsave(&priv->bgc.lock, flags);
311 
312 	/* Free underlying irq if last user unmapped */
313 	index = -1;
314 	for (i = 0; i < ngpio; i++) {
315 		lirq = &priv->lirqs[i];
316 		if (lirq->irq == irq) {
317 			grgpio_set_imask(priv, i, 0);
318 			lirq->irq = 0;
319 			index = lirq->index;
320 			break;
321 		}
322 	}
323 	WARN_ON(index < 0);
324 
325 	if (index >= 0) {
326 		uirq = &priv->uirqs[lirq->index];
327 		uirq->refcnt--;
328 		if (uirq->refcnt == 0)
329 			free_irq(uirq->uirq, priv);
330 	}
331 
332 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
333 }
334 
335 static struct irq_domain_ops grgpio_irq_domain_ops = {
336 	.map	= grgpio_irq_map,
337 	.unmap	= grgpio_irq_unmap,
338 };
339 
340 /* ------------------------------------------------------------ */
341 
342 static int grgpio_probe(struct platform_device *ofdev)
343 {
344 	struct device_node *np = ofdev->dev.of_node;
345 	void  __iomem *regs;
346 	struct gpio_chip *gc;
347 	struct bgpio_chip *bgc;
348 	struct grgpio_priv *priv;
349 	struct resource *res;
350 	int err;
351 	u32 prop;
352 	s32 *irqmap;
353 	int size;
354 	int i;
355 
356 	priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
357 	if (!priv)
358 		return -ENOMEM;
359 
360 	res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
361 	regs = devm_ioremap_resource(&ofdev->dev, res);
362 	if (IS_ERR(regs))
363 		return PTR_ERR(regs);
364 
365 	bgc = &priv->bgc;
366 	err = bgpio_init(bgc, &ofdev->dev, 4, regs + GRGPIO_DATA,
367 			 regs + GRGPIO_OUTPUT, NULL, regs + GRGPIO_DIR, NULL,
368 			 BGPIOF_BIG_ENDIAN_BYTE_ORDER);
369 	if (err) {
370 		dev_err(&ofdev->dev, "bgpio_init() failed\n");
371 		return err;
372 	}
373 
374 	priv->regs = regs;
375 	priv->imask = bgc->read_reg(regs + GRGPIO_IMASK);
376 	priv->dev = &ofdev->dev;
377 
378 	gc = &bgc->gc;
379 	gc->of_node = np;
380 	gc->owner = THIS_MODULE;
381 	gc->to_irq = grgpio_to_irq;
382 	gc->label = np->full_name;
383 	gc->base = -1;
384 
385 	err = of_property_read_u32(np, "nbits", &prop);
386 	if (err || prop <= 0 || prop > GRGPIO_MAX_NGPIO) {
387 		gc->ngpio = GRGPIO_MAX_NGPIO;
388 		dev_dbg(&ofdev->dev,
389 			"No or invalid nbits property: assume %d\n", gc->ngpio);
390 	} else {
391 		gc->ngpio = prop;
392 	}
393 
394 	/*
395 	 * The irqmap contains the index values indicating which underlying irq,
396 	 * if anyone, is connected to that line
397 	 */
398 	irqmap = (s32 *)of_get_property(np, "irqmap", &size);
399 	if (irqmap) {
400 		if (size < gc->ngpio) {
401 			dev_err(&ofdev->dev,
402 				"irqmap shorter than ngpio (%d < %d)\n",
403 				size, gc->ngpio);
404 			return -EINVAL;
405 		}
406 
407 		priv->domain = irq_domain_add_linear(np, gc->ngpio,
408 						     &grgpio_irq_domain_ops,
409 						     priv);
410 		if (!priv->domain) {
411 			dev_err(&ofdev->dev, "Could not add irq domain\n");
412 			return -EINVAL;
413 		}
414 
415 		for (i = 0; i < gc->ngpio; i++) {
416 			struct grgpio_lirq *lirq;
417 			int ret;
418 
419 			lirq = &priv->lirqs[i];
420 			lirq->index = irqmap[i];
421 
422 			if (lirq->index < 0)
423 				continue;
424 
425 			ret = platform_get_irq(ofdev, lirq->index);
426 			if (ret <= 0) {
427 				/*
428 				 * Continue without irq functionality for that
429 				 * gpio line
430 				 */
431 				dev_err(priv->dev,
432 					"Failed to get irq for offset %d\n", i);
433 				continue;
434 			}
435 			priv->uirqs[lirq->index].uirq = ret;
436 		}
437 	}
438 
439 	platform_set_drvdata(ofdev, priv);
440 
441 	err = gpiochip_add(gc);
442 	if (err) {
443 		dev_err(&ofdev->dev, "Could not add gpiochip\n");
444 		return err;
445 	}
446 
447 	dev_info(&ofdev->dev, "regs=0x%p, base=%d, ngpio=%d, irqs=%s\n",
448 		 priv->regs, gc->base, gc->ngpio, priv->domain ? "on" : "off");
449 
450 	return 0;
451 }
452 
453 static int grgpio_remove(struct platform_device *ofdev)
454 {
455 	struct grgpio_priv *priv = platform_get_drvdata(ofdev);
456 	unsigned long flags;
457 	int i;
458 	int ret = 0;
459 
460 	spin_lock_irqsave(&priv->bgc.lock, flags);
461 
462 	if (priv->domain) {
463 		for (i = 0; i < GRGPIO_MAX_NGPIO; i++) {
464 			if (priv->uirqs[i].refcnt != 0) {
465 				ret = -EBUSY;
466 				goto out;
467 			}
468 		}
469 	}
470 
471 	gpiochip_remove(&priv->bgc.gc);
472 
473 	if (priv->domain)
474 		irq_domain_remove(priv->domain);
475 
476 out:
477 	spin_unlock_irqrestore(&priv->bgc.lock, flags);
478 
479 	return ret;
480 }
481 
482 static const struct of_device_id grgpio_match[] = {
483 	{.name = "GAISLER_GPIO"},
484 	{.name = "01_01a"},
485 	{},
486 };
487 
488 MODULE_DEVICE_TABLE(of, grgpio_match);
489 
490 static struct platform_driver grgpio_driver = {
491 	.driver = {
492 		.name = "grgpio",
493 		.owner = THIS_MODULE,
494 		.of_match_table = grgpio_match,
495 	},
496 	.probe = grgpio_probe,
497 	.remove = grgpio_remove,
498 };
499 module_platform_driver(grgpio_driver);
500 
501 MODULE_AUTHOR("Aeroflex Gaisler AB.");
502 MODULE_DESCRIPTION("Driver for Aeroflex Gaisler GRGPIO");
503 MODULE_LICENSE("GPL");
504