xref: /openbmc/linux/drivers/gpio/gpio-grgpio.c (revision ddc141e5) 
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/gpio/driver.h>
35 #include <linux/interrupt.h>
36 #include <linux/irq.h>
37 #include <linux/irqdomain.h>
38 #include <linux/bitops.h>
39 
40 #define GRGPIO_MAX_NGPIO 32
41 
42 #define GRGPIO_DATA		0x00
43 #define GRGPIO_OUTPUT		0x04
44 #define GRGPIO_DIR		0x08
45 #define GRGPIO_IMASK		0x0c
46 #define GRGPIO_IPOL		0x10
47 #define GRGPIO_IEDGE		0x14
48 #define GRGPIO_BYPASS		0x18
49 #define GRGPIO_IMAP_BASE	0x20
50 
51 /* Structure for an irq of the core - called an underlying irq */
52 struct grgpio_uirq {
53 	u8 refcnt; /* Reference counter to manage requesting/freeing of uirq */
54 	u8 uirq; /* Underlying irq of the gpio driver */
55 };
56 
57 /*
58  * Structure for an irq of a gpio line handed out by this driver. The index is
59  * used to map to the corresponding underlying irq.
60  */
61 struct grgpio_lirq {
62 	s8 index; /* Index into struct grgpio_priv's uirqs, or -1 */
63 	u8 irq; /* irq for the gpio line */
64 };
65 
66 struct grgpio_priv {
67 	struct gpio_chip gc;
68 	void __iomem *regs;
69 	struct device *dev;
70 
71 	u32 imask; /* irq mask shadow register */
72 
73 	/*
74 	 * The grgpio core can have multiple "underlying" irqs. The gpio lines
75 	 * can be mapped to any one or none of these underlying irqs
76 	 * independently of each other. This driver sets up an irq domain and
77 	 * hands out separate irqs to each gpio line
78 	 */
79 	struct irq_domain *domain;
80 
81 	/*
82 	 * This array contains information on each underlying irq, each
83 	 * irq of the grgpio core itself.
84 	 */
85 	struct grgpio_uirq uirqs[GRGPIO_MAX_NGPIO];
86 
87 	/*
88 	 * This array contains information for each gpio line on the irqs
89 	 * obtains from this driver. An index value of -1 for a certain gpio
90 	 * line indicates that the line has no irq. Otherwise the index connects
91 	 * the irq to the underlying irq by pointing into the uirqs array.
92 	 */
93 	struct grgpio_lirq lirqs[GRGPIO_MAX_NGPIO];
94 };
95 
96 static void grgpio_set_imask(struct grgpio_priv *priv, unsigned int offset,
97 			     int val)
98 {
99 	struct gpio_chip *gc = &priv->gc;
100 
101 	if (val)
102 		priv->imask |= BIT(offset);
103 	else
104 		priv->imask &= ~BIT(offset);
105 	gc->write_reg(priv->regs + GRGPIO_IMASK, priv->imask);
106 }
107 
108 static int grgpio_to_irq(struct gpio_chip *gc, unsigned offset)
109 {
110 	struct grgpio_priv *priv = gpiochip_get_data(gc);
111 
112 	if (offset >= gc->ngpio)
113 		return -ENXIO;
114 
115 	if (priv->lirqs[offset].index < 0)
116 		return -ENXIO;
117 
118 	return irq_create_mapping(priv->domain, offset);
119 }
120 
121 /* -------------------- IRQ chip functions -------------------- */
122 
123 static int grgpio_irq_set_type(struct irq_data *d, unsigned int type)
124 {
125 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
126 	unsigned long flags;
127 	u32 mask = BIT(d->hwirq);
128 	u32 ipol;
129 	u32 iedge;
130 	u32 pol;
131 	u32 edge;
132 
133 	switch (type) {
134 	case IRQ_TYPE_LEVEL_LOW:
135 		pol = 0;
136 		edge = 0;
137 		break;
138 	case IRQ_TYPE_LEVEL_HIGH:
139 		pol = mask;
140 		edge = 0;
141 		break;
142 	case IRQ_TYPE_EDGE_FALLING:
143 		pol = 0;
144 		edge = mask;
145 		break;
146 	case IRQ_TYPE_EDGE_RISING:
147 		pol = mask;
148 		edge = mask;
149 		break;
150 	default:
151 		return -EINVAL;
152 	}
153 
154 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
155 
156 	ipol = priv->gc.read_reg(priv->regs + GRGPIO_IPOL) & ~mask;
157 	iedge = priv->gc.read_reg(priv->regs + GRGPIO_IEDGE) & ~mask;
158 
159 	priv->gc.write_reg(priv->regs + GRGPIO_IPOL, ipol | pol);
160 	priv->gc.write_reg(priv->regs + GRGPIO_IEDGE, iedge | edge);
161 
162 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
163 
164 	return 0;
165 }
166 
167 static void grgpio_irq_mask(struct irq_data *d)
168 {
169 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
170 	int offset = d->hwirq;
171 	unsigned long flags;
172 
173 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
174 
175 	grgpio_set_imask(priv, offset, 0);
176 
177 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
178 }
179 
180 static void grgpio_irq_unmask(struct irq_data *d)
181 {
182 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
183 	int offset = d->hwirq;
184 	unsigned long flags;
185 
186 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
187 
188 	grgpio_set_imask(priv, offset, 1);
189 
190 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
191 }
192 
193 static struct irq_chip grgpio_irq_chip = {
194 	.name			= "grgpio",
195 	.irq_mask		= grgpio_irq_mask,
196 	.irq_unmask		= grgpio_irq_unmask,
197 	.irq_set_type		= grgpio_irq_set_type,
198 };
199 
200 static irqreturn_t grgpio_irq_handler(int irq, void *dev)
201 {
202 	struct grgpio_priv *priv = dev;
203 	int ngpio = priv->gc.ngpio;
204 	unsigned long flags;
205 	int i;
206 	int match = 0;
207 
208 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
209 
210 	/*
211 	 * For each gpio line, call its interrupt handler if it its underlying
212 	 * irq matches the current irq that is handled.
213 	 */
214 	for (i = 0; i < ngpio; i++) {
215 		struct grgpio_lirq *lirq = &priv->lirqs[i];
216 
217 		if (priv->imask & BIT(i) && lirq->index >= 0 &&
218 		    priv->uirqs[lirq->index].uirq == irq) {
219 			generic_handle_irq(lirq->irq);
220 			match = 1;
221 		}
222 	}
223 
224 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
225 
226 	if (!match)
227 		dev_warn(priv->dev, "No gpio line matched irq %d\n", irq);
228 
229 	return IRQ_HANDLED;
230 }
231 
232 /*
233  * This function will be called as a consequence of the call to
234  * irq_create_mapping in grgpio_to_irq
235  */
236 static int grgpio_irq_map(struct irq_domain *d, unsigned int irq,
237 			  irq_hw_number_t hwirq)
238 {
239 	struct grgpio_priv *priv = d->host_data;
240 	struct grgpio_lirq *lirq;
241 	struct grgpio_uirq *uirq;
242 	unsigned long flags;
243 	int offset = hwirq;
244 	int ret = 0;
245 
246 	if (!priv)
247 		return -EINVAL;
248 
249 	lirq = &priv->lirqs[offset];
250 	if (lirq->index < 0)
251 		return -EINVAL;
252 
253 	dev_dbg(priv->dev, "Mapping irq %d for gpio line %d\n",
254 		irq, offset);
255 
256 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
257 
258 	/* Request underlying irq if not already requested */
259 	lirq->irq = irq;
260 	uirq = &priv->uirqs[lirq->index];
261 	if (uirq->refcnt == 0) {
262 		ret = request_irq(uirq->uirq, grgpio_irq_handler, 0,
263 				  dev_name(priv->dev), priv);
264 		if (ret) {
265 			dev_err(priv->dev,
266 				"Could not request underlying irq %d\n",
267 				uirq->uirq);
268 
269 			spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
270 
271 			return ret;
272 		}
273 	}
274 	uirq->refcnt++;
275 
276 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
277 
278 	/* Setup irq  */
279 	irq_set_chip_data(irq, priv);
280 	irq_set_chip_and_handler(irq, &grgpio_irq_chip,
281 				 handle_simple_irq);
282 	irq_set_noprobe(irq);
283 
284 	return ret;
285 }
286 
287 static void grgpio_irq_unmap(struct irq_domain *d, unsigned int irq)
288 {
289 	struct grgpio_priv *priv = d->host_data;
290 	int index;
291 	struct grgpio_lirq *lirq;
292 	struct grgpio_uirq *uirq;
293 	unsigned long flags;
294 	int ngpio = priv->gc.ngpio;
295 	int i;
296 
297 	irq_set_chip_and_handler(irq, NULL, NULL);
298 	irq_set_chip_data(irq, NULL);
299 
300 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
301 
302 	/* Free underlying irq if last user unmapped */
303 	index = -1;
304 	for (i = 0; i < ngpio; i++) {
305 		lirq = &priv->lirqs[i];
306 		if (lirq->irq == irq) {
307 			grgpio_set_imask(priv, i, 0);
308 			lirq->irq = 0;
309 			index = lirq->index;
310 			break;
311 		}
312 	}
313 	WARN_ON(index < 0);
314 
315 	if (index >= 0) {
316 		uirq = &priv->uirqs[lirq->index];
317 		uirq->refcnt--;
318 		if (uirq->refcnt == 0)
319 			free_irq(uirq->uirq, priv);
320 	}
321 
322 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
323 }
324 
325 static const struct irq_domain_ops grgpio_irq_domain_ops = {
326 	.map	= grgpio_irq_map,
327 	.unmap	= grgpio_irq_unmap,
328 };
329 
330 /* ------------------------------------------------------------ */
331 
332 static int grgpio_probe(struct platform_device *ofdev)
333 {
334 	struct device_node *np = ofdev->dev.of_node;
335 	void  __iomem *regs;
336 	struct gpio_chip *gc;
337 	struct grgpio_priv *priv;
338 	struct resource *res;
339 	int err;
340 	u32 prop;
341 	s32 *irqmap;
342 	int size;
343 	int i;
344 
345 	priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
346 	if (!priv)
347 		return -ENOMEM;
348 
349 	res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
350 	regs = devm_ioremap_resource(&ofdev->dev, res);
351 	if (IS_ERR(regs))
352 		return PTR_ERR(regs);
353 
354 	gc = &priv->gc;
355 	err = bgpio_init(gc, &ofdev->dev, 4, regs + GRGPIO_DATA,
356 			 regs + GRGPIO_OUTPUT, NULL, regs + GRGPIO_DIR, NULL,
357 			 BGPIOF_BIG_ENDIAN_BYTE_ORDER);
358 	if (err) {
359 		dev_err(&ofdev->dev, "bgpio_init() failed\n");
360 		return err;
361 	}
362 
363 	priv->regs = regs;
364 	priv->imask = gc->read_reg(regs + GRGPIO_IMASK);
365 	priv->dev = &ofdev->dev;
366 
367 	gc->of_node = np;
368 	gc->owner = THIS_MODULE;
369 	gc->to_irq = grgpio_to_irq;
370 	gc->label = devm_kasprintf(&ofdev->dev, GFP_KERNEL, "%pOF", np);
371 	gc->base = -1;
372 
373 	err = of_property_read_u32(np, "nbits", &prop);
374 	if (err || prop <= 0 || prop > GRGPIO_MAX_NGPIO) {
375 		gc->ngpio = GRGPIO_MAX_NGPIO;
376 		dev_dbg(&ofdev->dev,
377 			"No or invalid nbits property: assume %d\n", gc->ngpio);
378 	} else {
379 		gc->ngpio = prop;
380 	}
381 
382 	/*
383 	 * The irqmap contains the index values indicating which underlying irq,
384 	 * if anyone, is connected to that line
385 	 */
386 	irqmap = (s32 *)of_get_property(np, "irqmap", &size);
387 	if (irqmap) {
388 		if (size < gc->ngpio) {
389 			dev_err(&ofdev->dev,
390 				"irqmap shorter than ngpio (%d < %d)\n",
391 				size, gc->ngpio);
392 			return -EINVAL;
393 		}
394 
395 		priv->domain = irq_domain_add_linear(np, gc->ngpio,
396 						     &grgpio_irq_domain_ops,
397 						     priv);
398 		if (!priv->domain) {
399 			dev_err(&ofdev->dev, "Could not add irq domain\n");
400 			return -EINVAL;
401 		}
402 
403 		for (i = 0; i < gc->ngpio; i++) {
404 			struct grgpio_lirq *lirq;
405 			int ret;
406 
407 			lirq = &priv->lirqs[i];
408 			lirq->index = irqmap[i];
409 
410 			if (lirq->index < 0)
411 				continue;
412 
413 			ret = platform_get_irq(ofdev, lirq->index);
414 			if (ret <= 0) {
415 				/*
416 				 * Continue without irq functionality for that
417 				 * gpio line
418 				 */
419 				dev_err(priv->dev,
420 					"Failed to get irq for offset %d\n", i);
421 				continue;
422 			}
423 			priv->uirqs[lirq->index].uirq = ret;
424 		}
425 	}
426 
427 	platform_set_drvdata(ofdev, priv);
428 
429 	err = gpiochip_add_data(gc, priv);
430 	if (err) {
431 		dev_err(&ofdev->dev, "Could not add gpiochip\n");
432 		if (priv->domain)
433 			irq_domain_remove(priv->domain);
434 		return err;
435 	}
436 
437 	dev_info(&ofdev->dev, "regs=0x%p, base=%d, ngpio=%d, irqs=%s\n",
438 		 priv->regs, gc->base, gc->ngpio, priv->domain ? "on" : "off");
439 
440 	return 0;
441 }
442 
443 static int grgpio_remove(struct platform_device *ofdev)
444 {
445 	struct grgpio_priv *priv = platform_get_drvdata(ofdev);
446 	unsigned long flags;
447 	int i;
448 	int ret = 0;
449 
450 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
451 
452 	if (priv->domain) {
453 		for (i = 0; i < GRGPIO_MAX_NGPIO; i++) {
454 			if (priv->uirqs[i].refcnt != 0) {
455 				ret = -EBUSY;
456 				goto out;
457 			}
458 		}
459 	}
460 
461 	gpiochip_remove(&priv->gc);
462 
463 	if (priv->domain)
464 		irq_domain_remove(priv->domain);
465 
466 out:
467 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
468 
469 	return ret;
470 }
471 
472 static const struct of_device_id grgpio_match[] = {
473 	{.name = "GAISLER_GPIO"},
474 	{.name = "01_01a"},
475 	{},
476 };
477 
478 MODULE_DEVICE_TABLE(of, grgpio_match);
479 
480 static struct platform_driver grgpio_driver = {
481 	.driver = {
482 		.name = "grgpio",
483 		.of_match_table = grgpio_match,
484 	},
485 	.probe = grgpio_probe,
486 	.remove = grgpio_remove,
487 };
488 module_platform_driver(grgpio_driver);
489 
490 MODULE_AUTHOR("Aeroflex Gaisler AB.");
491 MODULE_DESCRIPTION("Driver for Aeroflex Gaisler GRGPIO");
492 MODULE_LICENSE("GPL");
493