1 // SPDX-License-Identifier: GPL-2.0-only
5 // Copyright (C) 2019-2020 Glider bv
7 #define DRV_NAME "gpio-aggregator"
8 #define pr_fmt(fmt) DRV_NAME ": " fmt
10 #include <linux/bitmap.h>
11 #include <linux/bitops.h>
12 #include <linux/ctype.h>
13 #include <linux/gpio.h>
14 #include <linux/gpio/consumer.h>
15 #include <linux/gpio/driver.h>
16 #include <linux/gpio/machine.h>
17 #include <linux/idr.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/mutex.h>
21 #include <linux/overflow.h>
22 #include <linux/platform_device.h>
23 #include <linux/spinlock.h>
24 #include <linux/string.h>
28 * GPIO Aggregator sysfs interface
31 struct gpio_aggregator {
32 struct gpiod_lookup_table *lookups;
33 struct platform_device *pdev;
37 static DEFINE_MUTEX(gpio_aggregator_lock); /* protects idr */
38 static DEFINE_IDR(gpio_aggregator_idr);
40 static char *get_arg(char **args)
44 start = skip_spaces(*args);
50 end = strchr(++start, '"');
52 return ERR_PTR(-EINVAL);
55 for (end = start; *end && !isspace(*end); end++) ;
65 static int aggr_add_gpio(struct gpio_aggregator *aggr, const char *key,
66 int hwnum, unsigned int *n)
68 struct gpiod_lookup_table *lookups;
70 lookups = krealloc(aggr->lookups, struct_size(lookups, table, *n + 2),
75 lookups->table[*n] = GPIO_LOOKUP_IDX(key, hwnum, NULL, *n, 0);
78 memset(&lookups->table[*n], 0, sizeof(lookups->table[*n]));
80 aggr->lookups = lookups;
84 static int aggr_parse(struct gpio_aggregator *aggr)
86 char *name, *offsets, *p;
87 char *args = aggr->args;
88 unsigned long *bitmap;
89 unsigned int i, n = 0;
92 bitmap = bitmap_alloc(ARCH_NR_GPIOS, GFP_KERNEL);
96 for (name = get_arg(&args), offsets = get_arg(&args); name;
97 offsets = get_arg(&args)) {
99 pr_err("Cannot get GPIO specifier: %pe\n", name);
100 error = PTR_ERR(name);
104 p = get_options(offsets, 0, &error);
105 if (error == 0 || *p) {
106 /* Named GPIO line */
107 error = aggr_add_gpio(aggr, name, U16_MAX, &n);
115 /* GPIO chip + offset(s) */
116 error = bitmap_parselist(offsets, bitmap, ARCH_NR_GPIOS);
118 pr_err("Cannot parse %s: %d\n", offsets, error);
122 for_each_set_bit(i, bitmap, ARCH_NR_GPIOS) {
123 error = aggr_add_gpio(aggr, name, i, &n);
128 name = get_arg(&args);
132 pr_err("No GPIOs specified\n");
141 static ssize_t new_device_store(struct device_driver *driver, const char *buf,
144 struct gpio_aggregator *aggr;
145 struct platform_device *pdev;
148 /* kernfs guarantees string termination, so count + 1 is safe */
149 aggr = kzalloc(sizeof(*aggr) + count + 1, GFP_KERNEL);
153 memcpy(aggr->args, buf, count + 1);
155 aggr->lookups = kzalloc(struct_size(aggr->lookups, table, 1),
157 if (!aggr->lookups) {
162 mutex_lock(&gpio_aggregator_lock);
163 id = idr_alloc(&gpio_aggregator_idr, aggr, 0, 0, GFP_KERNEL);
164 mutex_unlock(&gpio_aggregator_lock);
171 aggr->lookups->dev_id = kasprintf(GFP_KERNEL, "%s.%d", DRV_NAME, id);
172 if (!aggr->lookups->dev_id) {
177 res = aggr_parse(aggr);
181 gpiod_add_lookup_table(aggr->lookups);
183 pdev = platform_device_register_simple(DRV_NAME, id, NULL, 0);
193 gpiod_remove_lookup_table(aggr->lookups);
195 kfree(aggr->lookups->dev_id);
197 mutex_lock(&gpio_aggregator_lock);
198 idr_remove(&gpio_aggregator_idr, id);
199 mutex_unlock(&gpio_aggregator_lock);
201 kfree(aggr->lookups);
207 static DRIVER_ATTR_WO(new_device);
209 static void gpio_aggregator_free(struct gpio_aggregator *aggr)
211 platform_device_unregister(aggr->pdev);
212 gpiod_remove_lookup_table(aggr->lookups);
213 kfree(aggr->lookups->dev_id);
214 kfree(aggr->lookups);
218 static ssize_t delete_device_store(struct device_driver *driver,
219 const char *buf, size_t count)
221 struct gpio_aggregator *aggr;
225 if (!str_has_prefix(buf, DRV_NAME "."))
228 error = kstrtouint(buf + strlen(DRV_NAME "."), 10, &id);
232 mutex_lock(&gpio_aggregator_lock);
233 aggr = idr_remove(&gpio_aggregator_idr, id);
234 mutex_unlock(&gpio_aggregator_lock);
238 gpio_aggregator_free(aggr);
241 static DRIVER_ATTR_WO(delete_device);
243 static struct attribute *gpio_aggregator_attrs[] = {
244 &driver_attr_new_device.attr,
245 &driver_attr_delete_device.attr,
248 ATTRIBUTE_GROUPS(gpio_aggregator);
250 static int __exit gpio_aggregator_idr_remove(int id, void *p, void *data)
252 gpio_aggregator_free(p);
256 static void __exit gpio_aggregator_remove_all(void)
258 mutex_lock(&gpio_aggregator_lock);
259 idr_for_each(&gpio_aggregator_idr, gpio_aggregator_idr_remove, NULL);
260 idr_destroy(&gpio_aggregator_idr);
261 mutex_unlock(&gpio_aggregator_lock);
269 struct gpiochip_fwd {
270 struct gpio_chip chip;
271 struct gpio_desc **descs;
273 struct mutex mlock; /* protects tmp[] if can_sleep */
274 spinlock_t slock; /* protects tmp[] if !can_sleep */
276 unsigned long tmp[]; /* values and descs for multiple ops */
279 static int gpio_fwd_get_direction(struct gpio_chip *chip, unsigned int offset)
281 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
283 return gpiod_get_direction(fwd->descs[offset]);
286 static int gpio_fwd_direction_input(struct gpio_chip *chip, unsigned int offset)
288 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
290 return gpiod_direction_input(fwd->descs[offset]);
293 static int gpio_fwd_direction_output(struct gpio_chip *chip,
294 unsigned int offset, int value)
296 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
298 return gpiod_direction_output(fwd->descs[offset], value);
301 static int gpio_fwd_get(struct gpio_chip *chip, unsigned int offset)
303 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
305 return gpiod_get_value(fwd->descs[offset]);
308 static int gpio_fwd_get_multiple(struct gpiochip_fwd *fwd, unsigned long *mask,
311 struct gpio_desc **descs;
312 unsigned long *values;
313 unsigned int i, j = 0;
316 /* Both values bitmap and desc pointers are stored in tmp[] */
317 values = &fwd->tmp[0];
318 descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)];
320 bitmap_clear(values, 0, fwd->chip.ngpio);
321 for_each_set_bit(i, mask, fwd->chip.ngpio)
322 descs[j++] = fwd->descs[i];
324 error = gpiod_get_array_value(j, descs, NULL, values);
329 for_each_set_bit(i, mask, fwd->chip.ngpio)
330 __assign_bit(i, bits, test_bit(j++, values));
335 static int gpio_fwd_get_multiple_locked(struct gpio_chip *chip,
336 unsigned long *mask, unsigned long *bits)
338 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
342 if (chip->can_sleep) {
343 mutex_lock(&fwd->mlock);
344 error = gpio_fwd_get_multiple(fwd, mask, bits);
345 mutex_unlock(&fwd->mlock);
347 spin_lock_irqsave(&fwd->slock, flags);
348 error = gpio_fwd_get_multiple(fwd, mask, bits);
349 spin_unlock_irqrestore(&fwd->slock, flags);
355 static void gpio_fwd_set(struct gpio_chip *chip, unsigned int offset, int value)
357 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
359 gpiod_set_value(fwd->descs[offset], value);
362 static void gpio_fwd_set_multiple(struct gpiochip_fwd *fwd, unsigned long *mask,
365 struct gpio_desc **descs;
366 unsigned long *values;
367 unsigned int i, j = 0;
369 /* Both values bitmap and desc pointers are stored in tmp[] */
370 values = &fwd->tmp[0];
371 descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)];
373 for_each_set_bit(i, mask, fwd->chip.ngpio) {
374 __assign_bit(j, values, test_bit(i, bits));
375 descs[j++] = fwd->descs[i];
378 gpiod_set_array_value(j, descs, NULL, values);
381 static void gpio_fwd_set_multiple_locked(struct gpio_chip *chip,
382 unsigned long *mask, unsigned long *bits)
384 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
387 if (chip->can_sleep) {
388 mutex_lock(&fwd->mlock);
389 gpio_fwd_set_multiple(fwd, mask, bits);
390 mutex_unlock(&fwd->mlock);
392 spin_lock_irqsave(&fwd->slock, flags);
393 gpio_fwd_set_multiple(fwd, mask, bits);
394 spin_unlock_irqrestore(&fwd->slock, flags);
398 static int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset,
399 unsigned long config)
401 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
403 return gpiod_set_config(fwd->descs[offset], config);
407 * gpiochip_fwd_create() - Create a new GPIO forwarder
408 * @dev: Parent device pointer
409 * @ngpios: Number of GPIOs in the forwarder.
410 * @descs: Array containing the GPIO descriptors to forward to.
411 * This array must contain @ngpios entries, and must not be deallocated
412 * before the forwarder has been destroyed again.
414 * This function creates a new gpiochip, which forwards all GPIO operations to
415 * the passed GPIO descriptors.
417 * Return: An opaque object pointer, or an ERR_PTR()-encoded negative error
420 static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
422 struct gpio_desc *descs[])
424 const char *label = dev_name(dev);
425 struct gpiochip_fwd *fwd;
426 struct gpio_chip *chip;
430 fwd = devm_kzalloc(dev, struct_size(fwd, tmp,
431 BITS_TO_LONGS(ngpios) + ngpios), GFP_KERNEL);
433 return ERR_PTR(-ENOMEM);
438 * If any of the GPIO lines are sleeping, then the entire forwarder
440 * If any of the chips support .set_config(), then the forwarder will
441 * support setting configs.
443 for (i = 0; i < ngpios; i++) {
444 struct gpio_chip *parent = gpiod_to_chip(descs[i]);
446 dev_dbg(dev, "%u => gpio-%d\n", i, desc_to_gpio(descs[i]));
448 if (gpiod_cansleep(descs[i]))
449 chip->can_sleep = true;
450 if (parent && parent->set_config)
451 chip->set_config = gpio_fwd_set_config;
456 chip->owner = THIS_MODULE;
457 chip->get_direction = gpio_fwd_get_direction;
458 chip->direction_input = gpio_fwd_direction_input;
459 chip->direction_output = gpio_fwd_direction_output;
460 chip->get = gpio_fwd_get;
461 chip->get_multiple = gpio_fwd_get_multiple_locked;
462 chip->set = gpio_fwd_set;
463 chip->set_multiple = gpio_fwd_set_multiple_locked;
465 chip->ngpio = ngpios;
469 mutex_init(&fwd->mlock);
471 spin_lock_init(&fwd->slock);
473 error = devm_gpiochip_add_data(dev, chip, fwd);
475 return ERR_PTR(error);
482 * GPIO Aggregator platform device
485 static int gpio_aggregator_probe(struct platform_device *pdev)
487 struct device *dev = &pdev->dev;
488 struct gpio_desc **descs;
489 struct gpiochip_fwd *fwd;
492 n = gpiod_count(dev, NULL);
496 descs = devm_kmalloc_array(dev, n, sizeof(*descs), GFP_KERNEL);
500 for (i = 0; i < n; i++) {
501 descs[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
502 if (IS_ERR(descs[i]))
503 return PTR_ERR(descs[i]);
506 fwd = gpiochip_fwd_create(dev, n, descs);
510 platform_set_drvdata(pdev, fwd);
515 static const struct of_device_id gpio_aggregator_dt_ids[] = {
517 * Add GPIO-operated devices controlled from userspace below,
518 * or use "driver_override" in sysfs
522 MODULE_DEVICE_TABLE(of, gpio_aggregator_dt_ids);
525 static struct platform_driver gpio_aggregator_driver = {
526 .probe = gpio_aggregator_probe,
529 .groups = gpio_aggregator_groups,
530 .of_match_table = of_match_ptr(gpio_aggregator_dt_ids),
534 static int __init gpio_aggregator_init(void)
536 return platform_driver_register(&gpio_aggregator_driver);
538 module_init(gpio_aggregator_init);
540 static void __exit gpio_aggregator_exit(void)
542 gpio_aggregator_remove_all();
543 platform_driver_unregister(&gpio_aggregator_driver);
545 module_exit(gpio_aggregator_exit);
547 MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
548 MODULE_DESCRIPTION("GPIO Aggregator");
549 MODULE_LICENSE("GPL v2");