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1// SPDX-License-Identifier: GPL-2.0-only
2//
3// GPIO Aggregator
4//
5// Copyright (C) 2019-2020 Glider bv
6
7#define DRV_NAME "gpio-aggregator"
8#define pr_fmt(fmt) DRV_NAME ": " fmt
9
10#include <linux/bitmap.h>
11#include <linux/bitops.h>
12#include <linux/ctype.h>
13#include <linux/delay.h>
14#include <linux/idr.h>
15#include <linux/kernel.h>
16#include <linux/mod_devicetable.h>
17#include <linux/module.h>
18#include <linux/mutex.h>
19#include <linux/overflow.h>
20#include <linux/platform_device.h>
21#include <linux/property.h>
22#include <linux/slab.h>
23#include <linux/spinlock.h>
24#include <linux/string.h>
25
26#include <linux/gpio/consumer.h>
27#include <linux/gpio/driver.h>
28#include <linux/gpio/machine.h>
29
30#define AGGREGATOR_MAX_GPIOS 512
31
32/*
33 * GPIO Aggregator sysfs interface
34 */
35
36struct gpio_aggregator {
37 struct gpiod_lookup_table *lookups;
38 struct platform_device *pdev;
39 char args[];
40};
41
42static DEFINE_MUTEX(gpio_aggregator_lock); /* protects idr */
43static DEFINE_IDR(gpio_aggregator_idr);
44
45static int aggr_add_gpio(struct gpio_aggregator *aggr, const char *key,
46 int hwnum, unsigned int *n)
47{
48 struct gpiod_lookup_table *lookups;
49
50 lookups = krealloc(aggr->lookups, struct_size(lookups, table, *n + 2),
51 GFP_KERNEL);
52 if (!lookups)
53 return -ENOMEM;
54
55 lookups->table[*n] = GPIO_LOOKUP_IDX(key, hwnum, NULL, *n, 0);
56
57 (*n)++;
58 memset(&lookups->table[*n], 0, sizeof(lookups->table[*n]));
59
60 aggr->lookups = lookups;
61 return 0;
62}
63
64static int aggr_parse(struct gpio_aggregator *aggr)
65{
66 char *args = skip_spaces(aggr->args);
67 char *name, *offsets, *p;
68 unsigned int i, n = 0;
69 int error = 0;
70
71 unsigned long *bitmap __free(bitmap) =
72 bitmap_alloc(AGGREGATOR_MAX_GPIOS, GFP_KERNEL);
73 if (!bitmap)
74 return -ENOMEM;
75
76 args = next_arg(args, &name, &p);
77 while (*args) {
78 args = next_arg(args, &offsets, &p);
79
80 p = get_options(offsets, 0, &error);
81 if (error == 0 || *p) {
82 /* Named GPIO line */
83 error = aggr_add_gpio(aggr, name, U16_MAX, &n);
84 if (error)
85 return error;
86
87 name = offsets;
88 continue;
89 }
90
91 /* GPIO chip + offset(s) */
92 error = bitmap_parselist(offsets, bitmap, AGGREGATOR_MAX_GPIOS);
93 if (error) {
94 pr_err("Cannot parse %s: %d\n", offsets, error);
95 return error;
96 }
97
98 for_each_set_bit(i, bitmap, AGGREGATOR_MAX_GPIOS) {
99 error = aggr_add_gpio(aggr, name, i, &n);
100 if (error)
101 return error;
102 }
103
104 args = next_arg(args, &name, &p);
105 }
106
107 if (!n) {
108 pr_err("No GPIOs specified\n");
109 return -EINVAL;
110 }
111
112 return 0;
113}
114
115static ssize_t new_device_store(struct device_driver *driver, const char *buf,
116 size_t count)
117{
118 struct gpio_aggregator *aggr;
119 struct platform_device *pdev;
120 int res, id;
121
122 if (!try_module_get(THIS_MODULE))
123 return -ENOENT;
124
125 /* kernfs guarantees string termination, so count + 1 is safe */
126 aggr = kzalloc(sizeof(*aggr) + count + 1, GFP_KERNEL);
127 if (!aggr) {
128 res = -ENOMEM;
129 goto put_module;
130 }
131
132 memcpy(aggr->args, buf, count + 1);
133
134 aggr->lookups = kzalloc(struct_size(aggr->lookups, table, 1),
135 GFP_KERNEL);
136 if (!aggr->lookups) {
137 res = -ENOMEM;
138 goto free_ga;
139 }
140
141 mutex_lock(&gpio_aggregator_lock);
142 id = idr_alloc(&gpio_aggregator_idr, aggr, 0, 0, GFP_KERNEL);
143 mutex_unlock(&gpio_aggregator_lock);
144
145 if (id < 0) {
146 res = id;
147 goto free_table;
148 }
149
150 aggr->lookups->dev_id = kasprintf(GFP_KERNEL, "%s.%d", DRV_NAME, id);
151 if (!aggr->lookups->dev_id) {
152 res = -ENOMEM;
153 goto remove_idr;
154 }
155
156 res = aggr_parse(aggr);
157 if (res)
158 goto free_dev_id;
159
160 gpiod_add_lookup_table(aggr->lookups);
161
162 pdev = platform_device_register_simple(DRV_NAME, id, NULL, 0);
163 if (IS_ERR(pdev)) {
164 res = PTR_ERR(pdev);
165 goto remove_table;
166 }
167
168 aggr->pdev = pdev;
169 module_put(THIS_MODULE);
170 return count;
171
172remove_table:
173 gpiod_remove_lookup_table(aggr->lookups);
174free_dev_id:
175 kfree(aggr->lookups->dev_id);
176remove_idr:
177 mutex_lock(&gpio_aggregator_lock);
178 idr_remove(&gpio_aggregator_idr, id);
179 mutex_unlock(&gpio_aggregator_lock);
180free_table:
181 kfree(aggr->lookups);
182free_ga:
183 kfree(aggr);
184put_module:
185 module_put(THIS_MODULE);
186 return res;
187}
188
189static DRIVER_ATTR_WO(new_device);
190
191static void gpio_aggregator_free(struct gpio_aggregator *aggr)
192{
193 platform_device_unregister(aggr->pdev);
194 gpiod_remove_lookup_table(aggr->lookups);
195 kfree(aggr->lookups->dev_id);
196 kfree(aggr->lookups);
197 kfree(aggr);
198}
199
200static ssize_t delete_device_store(struct device_driver *driver,
201 const char *buf, size_t count)
202{
203 struct gpio_aggregator *aggr;
204 unsigned int id;
205 int error;
206
207 if (!str_has_prefix(buf, DRV_NAME "."))
208 return -EINVAL;
209
210 error = kstrtouint(buf + strlen(DRV_NAME "."), 10, &id);
211 if (error)
212 return error;
213
214 if (!try_module_get(THIS_MODULE))
215 return -ENOENT;
216
217 mutex_lock(&gpio_aggregator_lock);
218 aggr = idr_remove(&gpio_aggregator_idr, id);
219 mutex_unlock(&gpio_aggregator_lock);
220 if (!aggr) {
221 module_put(THIS_MODULE);
222 return -ENOENT;
223 }
224
225 gpio_aggregator_free(aggr);
226 module_put(THIS_MODULE);
227 return count;
228}
229static DRIVER_ATTR_WO(delete_device);
230
231static struct attribute *gpio_aggregator_attrs[] = {
232 &driver_attr_new_device.attr,
233 &driver_attr_delete_device.attr,
234 NULL
235};
236ATTRIBUTE_GROUPS(gpio_aggregator);
237
238static int __exit gpio_aggregator_idr_remove(int id, void *p, void *data)
239{
240 gpio_aggregator_free(p);
241 return 0;
242}
243
244static void __exit gpio_aggregator_remove_all(void)
245{
246 mutex_lock(&gpio_aggregator_lock);
247 idr_for_each(&gpio_aggregator_idr, gpio_aggregator_idr_remove, NULL);
248 idr_destroy(&gpio_aggregator_idr);
249 mutex_unlock(&gpio_aggregator_lock);
250}
251
252
253/*
254 * GPIO Forwarder
255 */
256
257struct gpiochip_fwd_timing {
258 u32 ramp_up_us;
259 u32 ramp_down_us;
260};
261
262struct gpiochip_fwd {
263 struct gpio_chip chip;
264 struct gpio_desc **descs;
265 union {
266 struct mutex mlock; /* protects tmp[] if can_sleep */
267 spinlock_t slock; /* protects tmp[] if !can_sleep */
268 };
269 struct gpiochip_fwd_timing *delay_timings;
270 unsigned long tmp[]; /* values and descs for multiple ops */
271};
272
273#define fwd_tmp_values(fwd) &(fwd)->tmp[0]
274#define fwd_tmp_descs(fwd) (void *)&(fwd)->tmp[BITS_TO_LONGS((fwd)->chip.ngpio)]
275
276#define fwd_tmp_size(ngpios) (BITS_TO_LONGS((ngpios)) + (ngpios))
277
278static int gpio_fwd_get_direction(struct gpio_chip *chip, unsigned int offset)
279{
280 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
281
282 return gpiod_get_direction(fwd->descs[offset]);
283}
284
285static int gpio_fwd_direction_input(struct gpio_chip *chip, unsigned int offset)
286{
287 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
288
289 return gpiod_direction_input(fwd->descs[offset]);
290}
291
292static int gpio_fwd_direction_output(struct gpio_chip *chip,
293 unsigned int offset, int value)
294{
295 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
296
297 return gpiod_direction_output(fwd->descs[offset], value);
298}
299
300static int gpio_fwd_get(struct gpio_chip *chip, unsigned int offset)
301{
302 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
303
304 return chip->can_sleep ? gpiod_get_value_cansleep(fwd->descs[offset])
305 : gpiod_get_value(fwd->descs[offset]);
306}
307
308static int gpio_fwd_get_multiple(struct gpiochip_fwd *fwd, unsigned long *mask,
309 unsigned long *bits)
310{
311 struct gpio_desc **descs = fwd_tmp_descs(fwd);
312 unsigned long *values = fwd_tmp_values(fwd);
313 unsigned int i, j = 0;
314 int error;
315
316 bitmap_clear(values, 0, fwd->chip.ngpio);
317 for_each_set_bit(i, mask, fwd->chip.ngpio)
318 descs[j++] = fwd->descs[i];
319
320 if (fwd->chip.can_sleep)
321 error = gpiod_get_array_value_cansleep(j, descs, NULL, values);
322 else
323 error = gpiod_get_array_value(j, descs, NULL, values);
324 if (error)
325 return error;
326
327 j = 0;
328 for_each_set_bit(i, mask, fwd->chip.ngpio)
329 __assign_bit(i, bits, test_bit(j++, values));
330
331 return 0;
332}
333
334static int gpio_fwd_get_multiple_locked(struct gpio_chip *chip,
335 unsigned long *mask, unsigned long *bits)
336{
337 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
338 unsigned long flags;
339 int error;
340
341 if (chip->can_sleep) {
342 mutex_lock(&fwd->mlock);
343 error = gpio_fwd_get_multiple(fwd, mask, bits);
344 mutex_unlock(&fwd->mlock);
345 } else {
346 spin_lock_irqsave(&fwd->slock, flags);
347 error = gpio_fwd_get_multiple(fwd, mask, bits);
348 spin_unlock_irqrestore(&fwd->slock, flags);
349 }
350
351 return error;
352}
353
354static void gpio_fwd_delay(struct gpio_chip *chip, unsigned int offset, int value)
355{
356 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
357 const struct gpiochip_fwd_timing *delay_timings;
358 bool is_active_low = gpiod_is_active_low(fwd->descs[offset]);
359 u32 delay_us;
360
361 delay_timings = &fwd->delay_timings[offset];
362 if ((!is_active_low && value) || (is_active_low && !value))
363 delay_us = delay_timings->ramp_up_us;
364 else
365 delay_us = delay_timings->ramp_down_us;
366 if (!delay_us)
367 return;
368
369 if (chip->can_sleep)
370 fsleep(delay_us);
371 else
372 udelay(delay_us);
373}
374
375static void gpio_fwd_set(struct gpio_chip *chip, unsigned int offset, int value)
376{
377 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
378
379 if (chip->can_sleep)
380 gpiod_set_value_cansleep(fwd->descs[offset], value);
381 else
382 gpiod_set_value(fwd->descs[offset], value);
383
384 if (fwd->delay_timings)
385 gpio_fwd_delay(chip, offset, value);
386}
387
388static void gpio_fwd_set_multiple(struct gpiochip_fwd *fwd, unsigned long *mask,
389 unsigned long *bits)
390{
391 struct gpio_desc **descs = fwd_tmp_descs(fwd);
392 unsigned long *values = fwd_tmp_values(fwd);
393 unsigned int i, j = 0;
394
395 for_each_set_bit(i, mask, fwd->chip.ngpio) {
396 __assign_bit(j, values, test_bit(i, bits));
397 descs[j++] = fwd->descs[i];
398 }
399
400 if (fwd->chip.can_sleep)
401 gpiod_set_array_value_cansleep(j, descs, NULL, values);
402 else
403 gpiod_set_array_value(j, descs, NULL, values);
404}
405
406static void gpio_fwd_set_multiple_locked(struct gpio_chip *chip,
407 unsigned long *mask, unsigned long *bits)
408{
409 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
410 unsigned long flags;
411
412 if (chip->can_sleep) {
413 mutex_lock(&fwd->mlock);
414 gpio_fwd_set_multiple(fwd, mask, bits);
415 mutex_unlock(&fwd->mlock);
416 } else {
417 spin_lock_irqsave(&fwd->slock, flags);
418 gpio_fwd_set_multiple(fwd, mask, bits);
419 spin_unlock_irqrestore(&fwd->slock, flags);
420 }
421}
422
423static int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset,
424 unsigned long config)
425{
426 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
427
428 return gpiod_set_config(fwd->descs[offset], config);
429}
430
431static int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset)
432{
433 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
434
435 return gpiod_to_irq(fwd->descs[offset]);
436}
437
438/*
439 * The GPIO delay provides a way to configure platform specific delays
440 * for the GPIO ramp-up or ramp-down delays. This can serve the following
441 * purposes:
442 * - Open-drain output using an RC filter
443 */
444#define FWD_FEATURE_DELAY BIT(0)
445
446#ifdef CONFIG_OF_GPIO
447static int gpiochip_fwd_delay_of_xlate(struct gpio_chip *chip,
448 const struct of_phandle_args *gpiospec,
449 u32 *flags)
450{
451 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
452 struct gpiochip_fwd_timing *timings;
453 u32 line;
454
455 if (gpiospec->args_count != chip->of_gpio_n_cells)
456 return -EINVAL;
457
458 line = gpiospec->args[0];
459 if (line >= chip->ngpio)
460 return -EINVAL;
461
462 timings = &fwd->delay_timings[line];
463 timings->ramp_up_us = gpiospec->args[1];
464 timings->ramp_down_us = gpiospec->args[2];
465
466 return line;
467}
468
469static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip,
470 struct gpiochip_fwd *fwd)
471{
472 fwd->delay_timings = devm_kcalloc(dev, chip->ngpio,
473 sizeof(*fwd->delay_timings),
474 GFP_KERNEL);
475 if (!fwd->delay_timings)
476 return -ENOMEM;
477
478 chip->of_xlate = gpiochip_fwd_delay_of_xlate;
479 chip->of_gpio_n_cells = 3;
480
481 return 0;
482}
483#else
484static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip,
485 struct gpiochip_fwd *fwd)
486{
487 return 0;
488}
489#endif /* !CONFIG_OF_GPIO */
490
491/**
492 * gpiochip_fwd_create() - Create a new GPIO forwarder
493 * @dev: Parent device pointer
494 * @ngpios: Number of GPIOs in the forwarder.
495 * @descs: Array containing the GPIO descriptors to forward to.
496 * This array must contain @ngpios entries, and must not be deallocated
497 * before the forwarder has been destroyed again.
498 * @features: Bitwise ORed features as defined with FWD_FEATURE_*.
499 *
500 * This function creates a new gpiochip, which forwards all GPIO operations to
501 * the passed GPIO descriptors.
502 *
503 * Return: An opaque object pointer, or an ERR_PTR()-encoded negative error
504 * code on failure.
505 */
506static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
507 unsigned int ngpios,
508 struct gpio_desc *descs[],
509 unsigned long features)
510{
511 const char *label = dev_name(dev);
512 struct gpiochip_fwd *fwd;
513 struct gpio_chip *chip;
514 unsigned int i;
515 int error;
516
517 fwd = devm_kzalloc(dev, struct_size(fwd, tmp, fwd_tmp_size(ngpios)),
518 GFP_KERNEL);
519 if (!fwd)
520 return ERR_PTR(-ENOMEM);
521
522 chip = &fwd->chip;
523
524 /*
525 * If any of the GPIO lines are sleeping, then the entire forwarder
526 * will be sleeping.
527 * If any of the chips support .set_config(), then the forwarder will
528 * support setting configs.
529 */
530 for (i = 0; i < ngpios; i++) {
531 struct gpio_chip *parent = gpiod_to_chip(descs[i]);
532
533 dev_dbg(dev, "%u => gpio %d irq %d\n", i,
534 desc_to_gpio(descs[i]), gpiod_to_irq(descs[i]));
535
536 if (gpiod_cansleep(descs[i]))
537 chip->can_sleep = true;
538 if (parent && parent->set_config)
539 chip->set_config = gpio_fwd_set_config;
540 }
541
542 chip->label = label;
543 chip->parent = dev;
544 chip->owner = THIS_MODULE;
545 chip->get_direction = gpio_fwd_get_direction;
546 chip->direction_input = gpio_fwd_direction_input;
547 chip->direction_output = gpio_fwd_direction_output;
548 chip->get = gpio_fwd_get;
549 chip->get_multiple = gpio_fwd_get_multiple_locked;
550 chip->set = gpio_fwd_set;
551 chip->set_multiple = gpio_fwd_set_multiple_locked;
552 chip->to_irq = gpio_fwd_to_irq;
553 chip->base = -1;
554 chip->ngpio = ngpios;
555 fwd->descs = descs;
556
557 if (chip->can_sleep)
558 mutex_init(&fwd->mlock);
559 else
560 spin_lock_init(&fwd->slock);
561
562 if (features & FWD_FEATURE_DELAY) {
563 error = gpiochip_fwd_setup_delay_line(dev, chip, fwd);
564 if (error)
565 return ERR_PTR(error);
566 }
567
568 error = devm_gpiochip_add_data(dev, chip, fwd);
569 if (error)
570 return ERR_PTR(error);
571
572 return fwd;
573}
574
575
576/*
577 * GPIO Aggregator platform device
578 */
579
580static int gpio_aggregator_probe(struct platform_device *pdev)
581{
582 struct device *dev = &pdev->dev;
583 struct gpio_desc **descs;
584 struct gpiochip_fwd *fwd;
585 unsigned long features;
586 int i, n;
587
588 n = gpiod_count(dev, NULL);
589 if (n < 0)
590 return n;
591
592 descs = devm_kmalloc_array(dev, n, sizeof(*descs), GFP_KERNEL);
593 if (!descs)
594 return -ENOMEM;
595
596 for (i = 0; i < n; i++) {
597 descs[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
598 if (IS_ERR(descs[i]))
599 return PTR_ERR(descs[i]);
600 }
601
602 features = (uintptr_t)device_get_match_data(dev);
603 fwd = gpiochip_fwd_create(dev, n, descs, features);
604 if (IS_ERR(fwd))
605 return PTR_ERR(fwd);
606
607 platform_set_drvdata(pdev, fwd);
608 return 0;
609}
610
611static const struct of_device_id gpio_aggregator_dt_ids[] = {
612 {
613 .compatible = "gpio-delay",
614 .data = (void *)FWD_FEATURE_DELAY,
615 },
616 /*
617 * Add GPIO-operated devices controlled from userspace below,
618 * or use "driver_override" in sysfs.
619 */
620 {}
621};
622MODULE_DEVICE_TABLE(of, gpio_aggregator_dt_ids);
623
624static struct platform_driver gpio_aggregator_driver = {
625 .probe = gpio_aggregator_probe,
626 .driver = {
627 .name = DRV_NAME,
628 .groups = gpio_aggregator_groups,
629 .of_match_table = gpio_aggregator_dt_ids,
630 },
631};
632
633static int __init gpio_aggregator_init(void)
634{
635 return platform_driver_register(&gpio_aggregator_driver);
636}
637module_init(gpio_aggregator_init);
638
639static void __exit gpio_aggregator_exit(void)
640{
641 gpio_aggregator_remove_all();
642 platform_driver_unregister(&gpio_aggregator_driver);
643}
644module_exit(gpio_aggregator_exit);
645
646MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
647MODULE_DESCRIPTION("GPIO Aggregator");
648MODULE_LICENSE("GPL v2");