xref: /openbmc/linux/drivers/gpio/gpio-grgpio.c (revision a44e4f3a) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Driver for Aeroflex Gaisler GRGPIO General Purpose I/O cores.
4  *
5  * 2013 (c) Aeroflex Gaisler AB
6  *
7  * This driver supports the GRGPIO GPIO core available in the GRLIB VHDL
8  * IP core library.
9  *
10  * Full documentation of the GRGPIO core can be found here:
11  * http://www.gaisler.com/products/grlib/grip.pdf
12  *
13  * See "Documentation/devicetree/bindings/gpio/gpio-grgpio.txt" for
14  * information on open firmware properties.
15  *
16  * Contributors: Andreas Larsson <andreas@gaisler.com>
17  */
18 
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/spinlock.h>
23 #include <linux/io.h>
24 #include <linux/of.h>
25 #include <linux/of_platform.h>
26 #include <linux/gpio/driver.h>
27 #include <linux/slab.h>
28 #include <linux/err.h>
29 #include <linux/interrupt.h>
30 #include <linux/irq.h>
31 #include <linux/irqdomain.h>
32 #include <linux/bitops.h>
33 
34 #define GRGPIO_MAX_NGPIO 32
35 
36 #define GRGPIO_DATA		0x00
37 #define GRGPIO_OUTPUT		0x04
38 #define GRGPIO_DIR		0x08
39 #define GRGPIO_IMASK		0x0c
40 #define GRGPIO_IPOL		0x10
41 #define GRGPIO_IEDGE		0x14
42 #define GRGPIO_BYPASS		0x18
43 #define GRGPIO_IMAP_BASE	0x20
44 
45 /* Structure for an irq of the core - called an underlying irq */
46 struct grgpio_uirq {
47 	u8 refcnt; /* Reference counter to manage requesting/freeing of uirq */
48 	u8 uirq; /* Underlying irq of the gpio driver */
49 };
50 
51 /*
52  * Structure for an irq of a gpio line handed out by this driver. The index is
53  * used to map to the corresponding underlying irq.
54  */
55 struct grgpio_lirq {
56 	s8 index; /* Index into struct grgpio_priv's uirqs, or -1 */
57 	u8 irq; /* irq for the gpio line */
58 };
59 
60 struct grgpio_priv {
61 	struct gpio_chip gc;
62 	void __iomem *regs;
63 	struct device *dev;
64 
65 	u32 imask; /* irq mask shadow register */
66 
67 	/*
68 	 * The grgpio core can have multiple "underlying" irqs. The gpio lines
69 	 * can be mapped to any one or none of these underlying irqs
70 	 * independently of each other. This driver sets up an irq domain and
71 	 * hands out separate irqs to each gpio line
72 	 */
73 	struct irq_domain *domain;
74 
75 	/*
76 	 * This array contains information on each underlying irq, each
77 	 * irq of the grgpio core itself.
78 	 */
79 	struct grgpio_uirq uirqs[GRGPIO_MAX_NGPIO];
80 
81 	/*
82 	 * This array contains information for each gpio line on the irqs
83 	 * obtains from this driver. An index value of -1 for a certain gpio
84 	 * line indicates that the line has no irq. Otherwise the index connects
85 	 * the irq to the underlying irq by pointing into the uirqs array.
86 	 */
87 	struct grgpio_lirq lirqs[GRGPIO_MAX_NGPIO];
88 };
89 
90 static void grgpio_set_imask(struct grgpio_priv *priv, unsigned int offset,
91 			     int val)
92 {
93 	struct gpio_chip *gc = &priv->gc;
94 
95 	if (val)
96 		priv->imask |= BIT(offset);
97 	else
98 		priv->imask &= ~BIT(offset);
99 	gc->write_reg(priv->regs + GRGPIO_IMASK, priv->imask);
100 }
101 
102 static int grgpio_to_irq(struct gpio_chip *gc, unsigned offset)
103 {
104 	struct grgpio_priv *priv = gpiochip_get_data(gc);
105 
106 	if (offset >= gc->ngpio)
107 		return -ENXIO;
108 
109 	if (priv->lirqs[offset].index < 0)
110 		return -ENXIO;
111 
112 	return irq_create_mapping(priv->domain, offset);
113 }
114 
115 /* -------------------- IRQ chip functions -------------------- */
116 
117 static int grgpio_irq_set_type(struct irq_data *d, unsigned int type)
118 {
119 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
120 	unsigned long flags;
121 	u32 mask = BIT(d->hwirq);
122 	u32 ipol;
123 	u32 iedge;
124 	u32 pol;
125 	u32 edge;
126 
127 	switch (type) {
128 	case IRQ_TYPE_LEVEL_LOW:
129 		pol = 0;
130 		edge = 0;
131 		break;
132 	case IRQ_TYPE_LEVEL_HIGH:
133 		pol = mask;
134 		edge = 0;
135 		break;
136 	case IRQ_TYPE_EDGE_FALLING:
137 		pol = 0;
138 		edge = mask;
139 		break;
140 	case IRQ_TYPE_EDGE_RISING:
141 		pol = mask;
142 		edge = mask;
143 		break;
144 	default:
145 		return -EINVAL;
146 	}
147 
148 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
149 
150 	ipol = priv->gc.read_reg(priv->regs + GRGPIO_IPOL) & ~mask;
151 	iedge = priv->gc.read_reg(priv->regs + GRGPIO_IEDGE) & ~mask;
152 
153 	priv->gc.write_reg(priv->regs + GRGPIO_IPOL, ipol | pol);
154 	priv->gc.write_reg(priv->regs + GRGPIO_IEDGE, iedge | edge);
155 
156 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
157 
158 	return 0;
159 }
160 
161 static void grgpio_irq_mask(struct irq_data *d)
162 {
163 	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
164 	int offset = d->hwirq;
165 	unsigned long flags;
166 
167 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
168 
169 	grgpio_set_imask(priv, offset, 0);
170 
171 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
172 }
173 
174 static void grgpio_irq_unmask(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->gc.bgpio_lock, flags);
181 
182 	grgpio_set_imask(priv, offset, 1);
183 
184 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
185 }
186 
187 static struct irq_chip grgpio_irq_chip = {
188 	.name			= "grgpio",
189 	.irq_mask		= grgpio_irq_mask,
190 	.irq_unmask		= grgpio_irq_unmask,
191 	.irq_set_type		= grgpio_irq_set_type,
192 };
193 
194 static irqreturn_t grgpio_irq_handler(int irq, void *dev)
195 {
196 	struct grgpio_priv *priv = dev;
197 	int ngpio = priv->gc.ngpio;
198 	unsigned long flags;
199 	int i;
200 	int match = 0;
201 
202 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
203 
204 	/*
205 	 * For each gpio line, call its interrupt handler if it its underlying
206 	 * irq matches the current irq that is handled.
207 	 */
208 	for (i = 0; i < ngpio; i++) {
209 		struct grgpio_lirq *lirq = &priv->lirqs[i];
210 
211 		if (priv->imask & BIT(i) && lirq->index >= 0 &&
212 		    priv->uirqs[lirq->index].uirq == irq) {
213 			generic_handle_irq(lirq->irq);
214 			match = 1;
215 		}
216 	}
217 
218 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
219 
220 	if (!match)
221 		dev_warn(priv->dev, "No gpio line matched irq %d\n", irq);
222 
223 	return IRQ_HANDLED;
224 }
225 
226 /*
227  * This function will be called as a consequence of the call to
228  * irq_create_mapping in grgpio_to_irq
229  */
230 static int grgpio_irq_map(struct irq_domain *d, unsigned int irq,
231 			  irq_hw_number_t hwirq)
232 {
233 	struct grgpio_priv *priv = d->host_data;
234 	struct grgpio_lirq *lirq;
235 	struct grgpio_uirq *uirq;
236 	unsigned long flags;
237 	int offset = hwirq;
238 	int ret = 0;
239 
240 	if (!priv)
241 		return -EINVAL;
242 
243 	lirq = &priv->lirqs[offset];
244 	if (lirq->index < 0)
245 		return -EINVAL;
246 
247 	dev_dbg(priv->dev, "Mapping irq %d for gpio line %d\n",
248 		irq, offset);
249 
250 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
251 
252 	/* Request underlying irq if not already requested */
253 	lirq->irq = irq;
254 	uirq = &priv->uirqs[lirq->index];
255 	if (uirq->refcnt == 0) {
256 		ret = request_irq(uirq->uirq, grgpio_irq_handler, 0,
257 				  dev_name(priv->dev), priv);
258 		if (ret) {
259 			dev_err(priv->dev,
260 				"Could not request underlying irq %d\n",
261 				uirq->uirq);
262 
263 			spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
264 
265 			return ret;
266 		}
267 	}
268 	uirq->refcnt++;
269 
270 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
271 
272 	/* Setup irq  */
273 	irq_set_chip_data(irq, priv);
274 	irq_set_chip_and_handler(irq, &grgpio_irq_chip,
275 				 handle_simple_irq);
276 	irq_set_noprobe(irq);
277 
278 	return ret;
279 }
280 
281 static void grgpio_irq_unmap(struct irq_domain *d, unsigned int irq)
282 {
283 	struct grgpio_priv *priv = d->host_data;
284 	int index;
285 	struct grgpio_lirq *lirq;
286 	struct grgpio_uirq *uirq;
287 	unsigned long flags;
288 	int ngpio = priv->gc.ngpio;
289 	int i;
290 
291 	irq_set_chip_and_handler(irq, NULL, NULL);
292 	irq_set_chip_data(irq, NULL);
293 
294 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
295 
296 	/* Free underlying irq if last user unmapped */
297 	index = -1;
298 	for (i = 0; i < ngpio; i++) {
299 		lirq = &priv->lirqs[i];
300 		if (lirq->irq == irq) {
301 			grgpio_set_imask(priv, i, 0);
302 			lirq->irq = 0;
303 			index = lirq->index;
304 			break;
305 		}
306 	}
307 	WARN_ON(index < 0);
308 
309 	if (index >= 0) {
310 		uirq = &priv->uirqs[lirq->index];
311 		uirq->refcnt--;
312 		if (uirq->refcnt == 0)
313 			free_irq(uirq->uirq, priv);
314 	}
315 
316 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
317 }
318 
319 static const struct irq_domain_ops grgpio_irq_domain_ops = {
320 	.map	= grgpio_irq_map,
321 	.unmap	= grgpio_irq_unmap,
322 };
323 
324 /* ------------------------------------------------------------ */
325 
326 static int grgpio_probe(struct platform_device *ofdev)
327 {
328 	struct device_node *np = ofdev->dev.of_node;
329 	void  __iomem *regs;
330 	struct gpio_chip *gc;
331 	struct grgpio_priv *priv;
332 	int err;
333 	u32 prop;
334 	s32 *irqmap;
335 	int size;
336 	int i;
337 
338 	priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
339 	if (!priv)
340 		return -ENOMEM;
341 
342 	regs = devm_platform_ioremap_resource(ofdev, 0);
343 	if (IS_ERR(regs))
344 		return PTR_ERR(regs);
345 
346 	gc = &priv->gc;
347 	err = bgpio_init(gc, &ofdev->dev, 4, regs + GRGPIO_DATA,
348 			 regs + GRGPIO_OUTPUT, NULL, regs + GRGPIO_DIR, NULL,
349 			 BGPIOF_BIG_ENDIAN_BYTE_ORDER);
350 	if (err) {
351 		dev_err(&ofdev->dev, "bgpio_init() failed\n");
352 		return err;
353 	}
354 
355 	priv->regs = regs;
356 	priv->imask = gc->read_reg(regs + GRGPIO_IMASK);
357 	priv->dev = &ofdev->dev;
358 
359 	gc->of_node = np;
360 	gc->owner = THIS_MODULE;
361 	gc->to_irq = grgpio_to_irq;
362 	gc->label = devm_kasprintf(&ofdev->dev, GFP_KERNEL, "%pOF", np);
363 	gc->base = -1;
364 
365 	err = of_property_read_u32(np, "nbits", &prop);
366 	if (err || prop <= 0 || prop > GRGPIO_MAX_NGPIO) {
367 		gc->ngpio = GRGPIO_MAX_NGPIO;
368 		dev_dbg(&ofdev->dev,
369 			"No or invalid nbits property: assume %d\n", gc->ngpio);
370 	} else {
371 		gc->ngpio = prop;
372 	}
373 
374 	/*
375 	 * The irqmap contains the index values indicating which underlying irq,
376 	 * if anyone, is connected to that line
377 	 */
378 	irqmap = (s32 *)of_get_property(np, "irqmap", &size);
379 	if (irqmap) {
380 		if (size < gc->ngpio) {
381 			dev_err(&ofdev->dev,
382 				"irqmap shorter than ngpio (%d < %d)\n",
383 				size, gc->ngpio);
384 			return -EINVAL;
385 		}
386 
387 		priv->domain = irq_domain_add_linear(np, gc->ngpio,
388 						     &grgpio_irq_domain_ops,
389 						     priv);
390 		if (!priv->domain) {
391 			dev_err(&ofdev->dev, "Could not add irq domain\n");
392 			return -EINVAL;
393 		}
394 
395 		for (i = 0; i < gc->ngpio; i++) {
396 			struct grgpio_lirq *lirq;
397 			int ret;
398 
399 			lirq = &priv->lirqs[i];
400 			lirq->index = irqmap[i];
401 
402 			if (lirq->index < 0)
403 				continue;
404 
405 			ret = platform_get_irq(ofdev, lirq->index);
406 			if (ret <= 0) {
407 				/*
408 				 * Continue without irq functionality for that
409 				 * gpio line
410 				 */
411 				continue;
412 			}
413 			priv->uirqs[lirq->index].uirq = ret;
414 		}
415 	}
416 
417 	platform_set_drvdata(ofdev, priv);
418 
419 	err = gpiochip_add_data(gc, priv);
420 	if (err) {
421 		dev_err(&ofdev->dev, "Could not add gpiochip\n");
422 		if (priv->domain)
423 			irq_domain_remove(priv->domain);
424 		return err;
425 	}
426 
427 	dev_info(&ofdev->dev, "regs=0x%p, base=%d, ngpio=%d, irqs=%s\n",
428 		 priv->regs, gc->base, gc->ngpio, priv->domain ? "on" : "off");
429 
430 	return 0;
431 }
432 
433 static int grgpio_remove(struct platform_device *ofdev)
434 {
435 	struct grgpio_priv *priv = platform_get_drvdata(ofdev);
436 	unsigned long flags;
437 	int i;
438 	int ret = 0;
439 
440 	spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
441 
442 	if (priv->domain) {
443 		for (i = 0; i < GRGPIO_MAX_NGPIO; i++) {
444 			if (priv->uirqs[i].refcnt != 0) {
445 				ret = -EBUSY;
446 				goto out;
447 			}
448 		}
449 	}
450 
451 	gpiochip_remove(&priv->gc);
452 
453 	if (priv->domain)
454 		irq_domain_remove(priv->domain);
455 
456 out:
457 	spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
458 
459 	return ret;
460 }
461 
462 static const struct of_device_id grgpio_match[] = {
463 	{.name = "GAISLER_GPIO"},
464 	{.name = "01_01a"},
465 	{},
466 };
467 
468 MODULE_DEVICE_TABLE(of, grgpio_match);
469 
470 static struct platform_driver grgpio_driver = {
471 	.driver = {
472 		.name = "grgpio",
473 		.of_match_table = grgpio_match,
474 	},
475 	.probe = grgpio_probe,
476 	.remove = grgpio_remove,
477 };
478 module_platform_driver(grgpio_driver);
479 
480 MODULE_AUTHOR("Aeroflex Gaisler AB.");
481 MODULE_DESCRIPTION("Driver for Aeroflex Gaisler GRGPIO");
482 MODULE_LICENSE("GPL");
483