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