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1 /*
2 * Generic driver for memory-mapped GPIO controllers.
3 *
4 * Copyright 2008 MontaVista Software, Inc.
5 * Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
11 *
12 * ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`.......
13 * ...`` ```````..
14 * ..The simplest form of a GPIO controller that the driver supports is``
15 * `.just a single "data" register, where GPIO state can be read and/or `
16 * `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````
17 * `````````
18 ___
19 _/~~|___/~| . ```~~~~~~ ___/___\___ ,~.`.`.`.`````.~~...,,,,...
20 __________|~$@~~~ %~ /o*o*o*o*o*o\ .. Implementing such a GPIO .
21 o ` ~~~~\___/~~~~ ` controller in FPGA is ,.`
22 `....trivial..'~`.```.```
23 * ```````
24 * .```````~~~~`..`.``.``.
25 * . The driver supports `... ,..```.`~~~```````````````....````.``,,
26 * . big-endian notation, just`. .. A bit more sophisticated controllers ,
27 * . register the device with -be`. .with a pair of set/clear-bit registers ,
28 * `.. suffix. ```~~`````....`.` . affecting the data register and the .`
29 * ``.`.``...``` ```.. output pins are also supported.`
30 * ^^ `````.`````````.,``~``~``~~``````
31 * . ^^
32 * ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`..
33 * .. The expectation is that in at least some cases . ,-~~~-,
34 * .this will be used with roll-your-own ASIC/FPGA .` \ /
35 * .logic in Verilog or VHDL. ~~~`````````..`````~~` \ /
36 * ..````````......``````````` \o_
37 * |
38 * ^^ / \
39 *
40 * ...`````~~`.....``.`..........``````.`.``.```........``.
41 * ` 8, 16, 32 and 64 bits registers are supported, and``.
42 * . the number of GPIOs is determined by the width of ~
43 * .. the registers. ,............```.`.`..`.`.~~~.`.`.`~
44 * `.......````.```
45 */
46
47 #include <linux/init.h>
48 #include <linux/err.h>
49 #include <linux/bug.h>
50 #include <linux/kernel.h>
51 #include <linux/module.h>
52 #include <linux/spinlock.h>
53 #include <linux/compiler.h>
54 #include <linux/types.h>
55 #include <linux/errno.h>
56 #include <linux/log2.h>
57 #include <linux/ioport.h>
58 #include <linux/io.h>
59 #include <linux/gpio/driver.h>
60 #include <linux/slab.h>
61 #include <linux/bitops.h>
62 #include <linux/platform_device.h>
63 #include <linux/mod_devicetable.h>
64 #include <linux/of.h>
65 #include <linux/of_device.h>
66
67 static void bgpio_write8(void __iomem *reg, unsigned long data)
68 {
69 writeb(data, reg);
70 }
71
72 static unsigned long bgpio_read8(void __iomem *reg)
73 {
74 return readb(reg);
75 }
76
77 static void bgpio_write16(void __iomem *reg, unsigned long data)
78 {
79 writew(data, reg);
80 }
81
82 static unsigned long bgpio_read16(void __iomem *reg)
83 {
84 return readw(reg);
85 }
86
87 static void bgpio_write32(void __iomem *reg, unsigned long data)
88 {
89 writel(data, reg);
90 }
91
92 static unsigned long bgpio_read32(void __iomem *reg)
93 {
94 return readl(reg);
95 }
96
97 #if BITS_PER_LONG >= 64
98 static void bgpio_write64(void __iomem *reg, unsigned long data)
99 {
100 writeq(data, reg);
101 }
102
103 static unsigned long bgpio_read64(void __iomem *reg)
104 {
105 return readq(reg);
106 }
107 #endif /* BITS_PER_LONG >= 64 */
108
109 static void bgpio_write16be(void __iomem *reg, unsigned long data)
110 {
111 iowrite16be(data, reg);
112 }
113
114 static unsigned long bgpio_read16be(void __iomem *reg)
115 {
116 return ioread16be(reg);
117 }
118
119 static void bgpio_write32be(void __iomem *reg, unsigned long data)
120 {
121 iowrite32be(data, reg);
122 }
123
124 static unsigned long bgpio_read32be(void __iomem *reg)
125 {
126 return ioread32be(reg);
127 }
128
129 static unsigned long bgpio_pin2mask(struct gpio_chip *gc, unsigned int pin)
130 {
131 return BIT(pin);
132 }
133
134 static unsigned long bgpio_pin2mask_be(struct gpio_chip *gc,
135 unsigned int pin)
136 {
137 return BIT(gc->bgpio_bits - 1 - pin);
138 }
139
140 static int bgpio_get_set(struct gpio_chip *gc, unsigned int gpio)
141 {
142 unsigned long pinmask = gc->pin2mask(gc, gpio);
143
144 if (gc->bgpio_dir & pinmask)
145 return !!(gc->read_reg(gc->reg_set) & pinmask);
146 else
147 return !!(gc->read_reg(gc->reg_dat) & pinmask);
148 }
149
150 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
151 {
152 return !!(gc->read_reg(gc->reg_dat) & gc->pin2mask(gc, gpio));
153 }
154
155 static void bgpio_set_none(struct gpio_chip *gc, unsigned int gpio, int val)
156 {
157 }
158
159 static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
160 {
161 unsigned long mask = gc->pin2mask(gc, gpio);
162 unsigned long flags;
163
164 spin_lock_irqsave(&gc->bgpio_lock, flags);
165
166 if (val)
167 gc->bgpio_data |= mask;
168 else
169 gc->bgpio_data &= ~mask;
170
171 gc->write_reg(gc->reg_dat, gc->bgpio_data);
172
173 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
174 }
175
176 static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
177 int val)
178 {
179 unsigned long mask = gc->pin2mask(gc, gpio);
180
181 if (val)
182 gc->write_reg(gc->reg_set, mask);
183 else
184 gc->write_reg(gc->reg_clr, mask);
185 }
186
187 static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
188 {
189 unsigned long mask = gc->pin2mask(gc, gpio);
190 unsigned long flags;
191
192 spin_lock_irqsave(&gc->bgpio_lock, flags);
193
194 if (val)
195 gc->bgpio_data |= mask;
196 else
197 gc->bgpio_data &= ~mask;
198
199 gc->write_reg(gc->reg_set, gc->bgpio_data);
200
201 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
202 }
203
204 static void bgpio_multiple_get_masks(struct gpio_chip *gc,
205 unsigned long *mask, unsigned long *bits,
206 unsigned long *set_mask,
207 unsigned long *clear_mask)
208 {
209 int i;
210
211 *set_mask = 0;
212 *clear_mask = 0;
213
214 for (i = 0; i < gc->bgpio_bits; i++) {
215 if (*mask == 0)
216 break;
217 if (__test_and_clear_bit(i, mask)) {
218 if (test_bit(i, bits))
219 *set_mask |= gc->pin2mask(gc, i);
220 else
221 *clear_mask |= gc->pin2mask(gc, i);
222 }
223 }
224 }
225
226 static void bgpio_set_multiple_single_reg(struct gpio_chip *gc,
227 unsigned long *mask,
228 unsigned long *bits,
229 void __iomem *reg)
230 {
231 unsigned long flags;
232 unsigned long set_mask, clear_mask;
233
234 spin_lock_irqsave(&gc->bgpio_lock, flags);
235
236 bgpio_multiple_get_masks(gc, mask, bits, &set_mask, &clear_mask);
237
238 gc->bgpio_data |= set_mask;
239 gc->bgpio_data &= ~clear_mask;
240
241 gc->write_reg(reg, gc->bgpio_data);
242
243 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
244 }
245
246 static void bgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
247 unsigned long *bits)
248 {
249 bgpio_set_multiple_single_reg(gc, mask, bits, gc->reg_dat);
250 }
251
252 static void bgpio_set_multiple_set(struct gpio_chip *gc, unsigned long *mask,
253 unsigned long *bits)
254 {
255 bgpio_set_multiple_single_reg(gc, mask, bits, gc->reg_set);
256 }
257
258 static void bgpio_set_multiple_with_clear(struct gpio_chip *gc,
259 unsigned long *mask,
260 unsigned long *bits)
261 {
262 unsigned long set_mask, clear_mask;
263
264 bgpio_multiple_get_masks(gc, mask, bits, &set_mask, &clear_mask);
265
266 if (set_mask)
267 gc->write_reg(gc->reg_set, set_mask);
268 if (clear_mask)
269 gc->write_reg(gc->reg_clr, clear_mask);
270 }
271
272 static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
273 {
274 return 0;
275 }
276
277 static int bgpio_dir_out_err(struct gpio_chip *gc, unsigned int gpio,
278 int val)
279 {
280 return -EINVAL;
281 }
282
283 static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
284 int val)
285 {
286 gc->set(gc, gpio, val);
287
288 return 0;
289 }
290
291 static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
292 {
293 unsigned long flags;
294
295 spin_lock_irqsave(&gc->bgpio_lock, flags);
296
297 gc->bgpio_dir &= ~gc->pin2mask(gc, gpio);
298 gc->write_reg(gc->reg_dir, gc->bgpio_dir);
299
300 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
301
302 return 0;
303 }
304
305 static int bgpio_get_dir(struct gpio_chip *gc, unsigned int gpio)
306 {
307 /* Return 0 if output, 1 of input */
308 return !(gc->read_reg(gc->reg_dir) & gc->pin2mask(gc, gpio));
309 }
310
311 static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
312 {
313 unsigned long flags;
314
315 gc->set(gc, gpio, val);
316
317 spin_lock_irqsave(&gc->bgpio_lock, flags);
318
319 gc->bgpio_dir |= gc->pin2mask(gc, gpio);
320 gc->write_reg(gc->reg_dir, gc->bgpio_dir);
321
322 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
323
324 return 0;
325 }
326
327 static int bgpio_dir_in_inv(struct gpio_chip *gc, unsigned int gpio)
328 {
329 unsigned long flags;
330
331 spin_lock_irqsave(&gc->bgpio_lock, flags);
332
333 gc->bgpio_dir |= gc->pin2mask(gc, gpio);
334 gc->write_reg(gc->reg_dir, gc->bgpio_dir);
335
336 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
337
338 return 0;
339 }
340
341 static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
342 {
343 unsigned long flags;
344
345 gc->set(gc, gpio, val);
346
347 spin_lock_irqsave(&gc->bgpio_lock, flags);
348
349 gc->bgpio_dir &= ~gc->pin2mask(gc, gpio);
350 gc->write_reg(gc->reg_dir, gc->bgpio_dir);
351
352 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
353
354 return 0;
355 }
356
357 static int bgpio_get_dir_inv(struct gpio_chip *gc, unsigned int gpio)
358 {
359 /* Return 0 if output, 1 if input */
360 return !!(gc->read_reg(gc->reg_dir) & gc->pin2mask(gc, gpio));
361 }
362
363 static int bgpio_setup_accessors(struct device *dev,
364 struct gpio_chip *gc,
365 bool bit_be,
366 bool byte_be)
367 {
368
369 switch (gc->bgpio_bits) {
370 case 8:
371 gc->read_reg = bgpio_read8;
372 gc->write_reg = bgpio_write8;
373 break;
374 case 16:
375 if (byte_be) {
376 gc->read_reg = bgpio_read16be;
377 gc->write_reg = bgpio_write16be;
378 } else {
379 gc->read_reg = bgpio_read16;
380 gc->write_reg = bgpio_write16;
381 }
382 break;
383 case 32:
384 if (byte_be) {
385 gc->read_reg = bgpio_read32be;
386 gc->write_reg = bgpio_write32be;
387 } else {
388 gc->read_reg = bgpio_read32;
389 gc->write_reg = bgpio_write32;
390 }
391 break;
392 #if BITS_PER_LONG >= 64
393 case 64:
394 if (byte_be) {
395 dev_err(dev,
396 "64 bit big endian byte order unsupported\n");
397 return -EINVAL;
398 } else {
399 gc->read_reg = bgpio_read64;
400 gc->write_reg = bgpio_write64;
401 }
402 break;
403 #endif /* BITS_PER_LONG >= 64 */
404 default:
405 dev_err(dev, "unsupported data width %u bits\n", gc->bgpio_bits);
406 return -EINVAL;
407 }
408
409 gc->pin2mask = bit_be ? bgpio_pin2mask_be : bgpio_pin2mask;
410
411 return 0;
412 }
413
414 /*
415 * Create the device and allocate the resources. For setting GPIO's there are
416 * three supported configurations:
417 *
418 * - single input/output register resource (named "dat").
419 * - set/clear pair (named "set" and "clr").
420 * - single output register resource and single input resource ("set" and
421 * dat").
422 *
423 * For the single output register, this drives a 1 by setting a bit and a zero
424 * by clearing a bit. For the set clr pair, this drives a 1 by setting a bit
425 * in the set register and clears it by setting a bit in the clear register.
426 * The configuration is detected by which resources are present.
427 *
428 * For setting the GPIO direction, there are three supported configurations:
429 *
430 * - simple bidirection GPIO that requires no configuration.
431 * - an output direction register (named "dirout") where a 1 bit
432 * indicates the GPIO is an output.
433 * - an input direction register (named "dirin") where a 1 bit indicates
434 * the GPIO is an input.
435 */
436 static int bgpio_setup_io(struct gpio_chip *gc,
437 void __iomem *dat,
438 void __iomem *set,
439 void __iomem *clr,
440 unsigned long flags)
441 {
442
443 gc->reg_dat = dat;
444 if (!gc->reg_dat)
445 return -EINVAL;
446
447 if (set && clr) {
448 gc->reg_set = set;
449 gc->reg_clr = clr;
450 gc->set = bgpio_set_with_clear;
451 gc->set_multiple = bgpio_set_multiple_with_clear;
452 } else if (set && !clr) {
453 gc->reg_set = set;
454 gc->set = bgpio_set_set;
455 gc->set_multiple = bgpio_set_multiple_set;
456 } else if (flags & BGPIOF_NO_OUTPUT) {
457 gc->set = bgpio_set_none;
458 gc->set_multiple = NULL;
459 } else {
460 gc->set = bgpio_set;
461 gc->set_multiple = bgpio_set_multiple;
462 }
463
464 if (!(flags & BGPIOF_UNREADABLE_REG_SET) &&
465 (flags & BGPIOF_READ_OUTPUT_REG_SET))
466 gc->get = bgpio_get_set;
467 else
468 gc->get = bgpio_get;
469
470 return 0;
471 }
472
473 static int bgpio_setup_direction(struct gpio_chip *gc,
474 void __iomem *dirout,
475 void __iomem *dirin,
476 unsigned long flags)
477 {
478 if (dirout && dirin) {
479 return -EINVAL;
480 } else if (dirout) {
481 gc->reg_dir = dirout;
482 gc->direction_output = bgpio_dir_out;
483 gc->direction_input = bgpio_dir_in;
484 gc->get_direction = bgpio_get_dir;
485 } else if (dirin) {
486 gc->reg_dir = dirin;
487 gc->direction_output = bgpio_dir_out_inv;
488 gc->direction_input = bgpio_dir_in_inv;
489 gc->get_direction = bgpio_get_dir_inv;
490 } else {
491 if (flags & BGPIOF_NO_OUTPUT)
492 gc->direction_output = bgpio_dir_out_err;
493 else
494 gc->direction_output = bgpio_simple_dir_out;
495 gc->direction_input = bgpio_simple_dir_in;
496 }
497
498 return 0;
499 }
500
501 static int bgpio_request(struct gpio_chip *chip, unsigned gpio_pin)
502 {
503 if (gpio_pin < chip->ngpio)
504 return 0;
505
506 return -EINVAL;
507 }
508
509 int bgpio_init(struct gpio_chip *gc, struct device *dev,
510 unsigned long sz, void __iomem *dat, void __iomem *set,
511 void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
512 unsigned long flags)
513 {
514 int ret;
515
516 if (!is_power_of_2(sz))
517 return -EINVAL;
518
519 gc->bgpio_bits = sz * 8;
520 if (gc->bgpio_bits > BITS_PER_LONG)
521 return -EINVAL;
522
523 spin_lock_init(&gc->bgpio_lock);
524 gc->parent = dev;
525 gc->label = dev_name(dev);
526 gc->base = -1;
527 gc->ngpio = gc->bgpio_bits;
528 gc->request = bgpio_request;
529
530 ret = bgpio_setup_io(gc, dat, set, clr, flags);
531 if (ret)
532 return ret;
533
534 ret = bgpio_setup_accessors(dev, gc, flags & BGPIOF_BIG_ENDIAN,
535 flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
536 if (ret)
537 return ret;
538
539 ret = bgpio_setup_direction(gc, dirout, dirin, flags);
540 if (ret)
541 return ret;
542
543 gc->bgpio_data = gc->read_reg(gc->reg_dat);
544 if (gc->set == bgpio_set_set &&
545 !(flags & BGPIOF_UNREADABLE_REG_SET))
546 gc->bgpio_data = gc->read_reg(gc->reg_set);
547 if (gc->reg_dir && !(flags & BGPIOF_UNREADABLE_REG_DIR))
548 gc->bgpio_dir = gc->read_reg(gc->reg_dir);
549
550 return ret;
551 }
552 EXPORT_SYMBOL_GPL(bgpio_init);
553
554 #if IS_ENABLED(CONFIG_GPIO_GENERIC_PLATFORM)
555
556 static void __iomem *bgpio_map(struct platform_device *pdev,
557 const char *name,
558 resource_size_t sane_sz)
559 {
560 struct resource *r;
561 resource_size_t sz;
562
563 r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
564 if (!r)
565 return NULL;
566
567 sz = resource_size(r);
568 if (sz != sane_sz)
569 return IOMEM_ERR_PTR(-EINVAL);
570
571 return devm_ioremap_resource(&pdev->dev, r);
572 }
573
574 #ifdef CONFIG_OF
575 static const struct of_device_id bgpio_of_match[] = {
576 { .compatible = "brcm,bcm6345-gpio" },
577 { .compatible = "wd,mbl-gpio" },
578 { .compatible = "ni,169445-nand-gpio" },
579 { }
580 };
581 MODULE_DEVICE_TABLE(of, bgpio_of_match);
582
583 static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
584 unsigned long *flags)
585 {
586 struct bgpio_pdata *pdata;
587
588 if (!of_match_device(bgpio_of_match, &pdev->dev))
589 return NULL;
590
591 pdata = devm_kzalloc(&pdev->dev, sizeof(struct bgpio_pdata),
592 GFP_KERNEL);
593 if (!pdata)
594 return ERR_PTR(-ENOMEM);
595
596 pdata->base = -1;
597
598 if (of_device_is_big_endian(pdev->dev.of_node))
599 *flags |= BGPIOF_BIG_ENDIAN_BYTE_ORDER;
600
601 if (of_property_read_bool(pdev->dev.of_node, "no-output"))
602 *flags |= BGPIOF_NO_OUTPUT;
603
604 return pdata;
605 }
606 #else
607 static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
608 unsigned long *flags)
609 {
610 return NULL;
611 }
612 #endif /* CONFIG_OF */
613
614 static int bgpio_pdev_probe(struct platform_device *pdev)
615 {
616 struct device *dev = &pdev->dev;
617 struct resource *r;
618 void __iomem *dat;
619 void __iomem *set;
620 void __iomem *clr;
621 void __iomem *dirout;
622 void __iomem *dirin;
623 unsigned long sz;
624 unsigned long flags = 0;
625 int err;
626 struct gpio_chip *gc;
627 struct bgpio_pdata *pdata;
628
629 pdata = bgpio_parse_dt(pdev, &flags);
630 if (IS_ERR(pdata))
631 return PTR_ERR(pdata);
632
633 if (!pdata) {
634 pdata = dev_get_platdata(dev);
635 flags = pdev->id_entry->driver_data;
636 }
637
638 r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
639 if (!r)
640 return -EINVAL;
641
642 sz = resource_size(r);
643
644 dat = bgpio_map(pdev, "dat", sz);
645 if (IS_ERR(dat))
646 return PTR_ERR(dat);
647
648 set = bgpio_map(pdev, "set", sz);
649 if (IS_ERR(set))
650 return PTR_ERR(set);
651
652 clr = bgpio_map(pdev, "clr", sz);
653 if (IS_ERR(clr))
654 return PTR_ERR(clr);
655
656 dirout = bgpio_map(pdev, "dirout", sz);
657 if (IS_ERR(dirout))
658 return PTR_ERR(dirout);
659
660 dirin = bgpio_map(pdev, "dirin", sz);
661 if (IS_ERR(dirin))
662 return PTR_ERR(dirin);
663
664 gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
665 if (!gc)
666 return -ENOMEM;
667
668 err = bgpio_init(gc, dev, sz, dat, set, clr, dirout, dirin, flags);
669 if (err)
670 return err;
671
672 if (pdata) {
673 if (pdata->label)
674 gc->label = pdata->label;
675 gc->base = pdata->base;
676 if (pdata->ngpio > 0)
677 gc->ngpio = pdata->ngpio;
678 }
679
680 platform_set_drvdata(pdev, gc);
681
682 return devm_gpiochip_add_data(&pdev->dev, gc, NULL);
683 }
684
685 static const struct platform_device_id bgpio_id_table[] = {
686 {
687 .name = "basic-mmio-gpio",
688 .driver_data = 0,
689 }, {
690 .name = "basic-mmio-gpio-be",
691 .driver_data = BGPIOF_BIG_ENDIAN,
692 },
693 { }
694 };
695 MODULE_DEVICE_TABLE(platform, bgpio_id_table);
696
697 static struct platform_driver bgpio_driver = {
698 .driver = {
699 .name = "basic-mmio-gpio",
700 .of_match_table = of_match_ptr(bgpio_of_match),
701 },
702 .id_table = bgpio_id_table,
703 .probe = bgpio_pdev_probe,
704 };
705
706 module_platform_driver(bgpio_driver);
707
708 #endif /* CONFIG_GPIO_GENERIC_PLATFORM */
709
710 MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
711 MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
712 MODULE_LICENSE("GPL");