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 bool isrange(const char *s)
69 if (IS_ERR_OR_NULL(s))
73 n = strspn(s, "0123456789");
93 static int aggr_add_gpio(struct gpio_aggregator *aggr, const char *key,
94 int hwnum, unsigned int *n)
96 struct gpiod_lookup_table *lookups;
98 lookups = krealloc(aggr->lookups, struct_size(lookups, table, *n + 2),
104 (struct gpiod_lookup)GPIO_LOOKUP_IDX(key, hwnum, NULL, *n, 0);
107 memset(&lookups->table[*n], 0, sizeof(lookups->table[*n]));
109 aggr->lookups = lookups;
113 static int aggr_parse(struct gpio_aggregator *aggr)
115 char *args = aggr->args;
116 unsigned long *bitmap;
117 unsigned int i, n = 0;
118 char *name, *offsets;
121 bitmap = bitmap_alloc(ARCH_NR_GPIOS, GFP_KERNEL);
125 for (name = get_arg(&args), offsets = get_arg(&args); name;
126 offsets = get_arg(&args)) {
128 pr_err("Cannot get GPIO specifier: %pe\n", name);
129 error = PTR_ERR(name);
133 if (!isrange(offsets)) {
134 /* Named GPIO line */
135 error = aggr_add_gpio(aggr, name, U16_MAX, &n);
143 /* GPIO chip + offset(s) */
144 error = bitmap_parselist(offsets, bitmap, ARCH_NR_GPIOS);
146 pr_err("Cannot parse %s: %d\n", offsets, error);
150 for_each_set_bit(i, bitmap, ARCH_NR_GPIOS) {
151 error = aggr_add_gpio(aggr, name, i, &n);
156 name = get_arg(&args);
160 pr_err("No GPIOs specified\n");
169 static ssize_t new_device_store(struct device_driver *driver, const char *buf,
172 struct gpio_aggregator *aggr;
173 struct platform_device *pdev;
176 /* kernfs guarantees string termination, so count + 1 is safe */
177 aggr = kzalloc(sizeof(*aggr) + count + 1, GFP_KERNEL);
181 memcpy(aggr->args, buf, count + 1);
183 aggr->lookups = kzalloc(struct_size(aggr->lookups, table, 1),
185 if (!aggr->lookups) {
190 mutex_lock(&gpio_aggregator_lock);
191 id = idr_alloc(&gpio_aggregator_idr, aggr, 0, 0, GFP_KERNEL);
192 mutex_unlock(&gpio_aggregator_lock);
199 aggr->lookups->dev_id = kasprintf(GFP_KERNEL, "%s.%d", DRV_NAME, id);
200 if (!aggr->lookups->dev_id) {
205 res = aggr_parse(aggr);
209 gpiod_add_lookup_table(aggr->lookups);
211 pdev = platform_device_register_simple(DRV_NAME, id, NULL, 0);
221 gpiod_remove_lookup_table(aggr->lookups);
223 kfree(aggr->lookups->dev_id);
225 mutex_lock(&gpio_aggregator_lock);
226 idr_remove(&gpio_aggregator_idr, id);
227 mutex_unlock(&gpio_aggregator_lock);
229 kfree(aggr->lookups);
235 static DRIVER_ATTR_WO(new_device);
237 static void gpio_aggregator_free(struct gpio_aggregator *aggr)
239 platform_device_unregister(aggr->pdev);
240 gpiod_remove_lookup_table(aggr->lookups);
241 kfree(aggr->lookups->dev_id);
242 kfree(aggr->lookups);
246 static ssize_t delete_device_store(struct device_driver *driver,
247 const char *buf, size_t count)
249 struct gpio_aggregator *aggr;
253 if (!str_has_prefix(buf, DRV_NAME "."))
256 error = kstrtouint(buf + strlen(DRV_NAME "."), 10, &id);
260 mutex_lock(&gpio_aggregator_lock);
261 aggr = idr_remove(&gpio_aggregator_idr, id);
262 mutex_unlock(&gpio_aggregator_lock);
266 gpio_aggregator_free(aggr);
269 static DRIVER_ATTR_WO(delete_device);
271 static struct attribute *gpio_aggregator_attrs[] = {
272 &driver_attr_new_device.attr,
273 &driver_attr_delete_device.attr,
276 ATTRIBUTE_GROUPS(gpio_aggregator);
278 static int __exit gpio_aggregator_idr_remove(int id, void *p, void *data)
280 gpio_aggregator_free(p);
284 static void __exit gpio_aggregator_remove_all(void)
286 mutex_lock(&gpio_aggregator_lock);
287 idr_for_each(&gpio_aggregator_idr, gpio_aggregator_idr_remove, NULL);
288 idr_destroy(&gpio_aggregator_idr);
289 mutex_unlock(&gpio_aggregator_lock);
297 struct gpiochip_fwd {
298 struct gpio_chip chip;
299 struct gpio_desc **descs;
301 struct mutex mlock; /* protects tmp[] if can_sleep */
302 spinlock_t slock; /* protects tmp[] if !can_sleep */
304 unsigned long tmp[]; /* values and descs for multiple ops */
307 static int gpio_fwd_get_direction(struct gpio_chip *chip, unsigned int offset)
309 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
311 return gpiod_get_direction(fwd->descs[offset]);
314 static int gpio_fwd_direction_input(struct gpio_chip *chip, unsigned int offset)
316 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
318 return gpiod_direction_input(fwd->descs[offset]);
321 static int gpio_fwd_direction_output(struct gpio_chip *chip,
322 unsigned int offset, int value)
324 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
326 return gpiod_direction_output(fwd->descs[offset], value);
329 static int gpio_fwd_get(struct gpio_chip *chip, unsigned int offset)
331 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
333 return gpiod_get_value(fwd->descs[offset]);
336 static int gpio_fwd_get_multiple(struct gpio_chip *chip, unsigned long *mask,
339 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
340 unsigned long *values, flags = 0;
341 struct gpio_desc **descs;
342 unsigned int i, j = 0;
346 mutex_lock(&fwd->mlock);
348 spin_lock_irqsave(&fwd->slock, flags);
350 /* Both values bitmap and desc pointers are stored in tmp[] */
351 values = &fwd->tmp[0];
352 descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)];
354 bitmap_clear(values, 0, fwd->chip.ngpio);
355 for_each_set_bit(i, mask, fwd->chip.ngpio)
356 descs[j++] = fwd->descs[i];
358 error = gpiod_get_array_value(j, descs, NULL, values);
361 for_each_set_bit(i, mask, fwd->chip.ngpio)
362 __assign_bit(i, bits, test_bit(j++, values));
366 mutex_unlock(&fwd->mlock);
368 spin_unlock_irqrestore(&fwd->slock, flags);
373 static void gpio_fwd_set(struct gpio_chip *chip, unsigned int offset, int value)
375 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
377 gpiod_set_value(fwd->descs[offset], value);
380 static void gpio_fwd_set_multiple(struct gpio_chip *chip, unsigned long *mask,
383 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
384 unsigned long *values, flags = 0;
385 struct gpio_desc **descs;
386 unsigned int i, j = 0;
389 mutex_lock(&fwd->mlock);
391 spin_lock_irqsave(&fwd->slock, flags);
393 /* Both values bitmap and desc pointers are stored in tmp[] */
394 values = &fwd->tmp[0];
395 descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)];
397 for_each_set_bit(i, mask, fwd->chip.ngpio) {
398 __assign_bit(j, values, test_bit(i, bits));
399 descs[j++] = fwd->descs[i];
402 gpiod_set_array_value(j, descs, NULL, values);
405 mutex_unlock(&fwd->mlock);
407 spin_unlock_irqrestore(&fwd->slock, flags);
410 static int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset,
411 unsigned long config)
413 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
415 return gpiod_set_config(fwd->descs[offset], config);
419 * gpiochip_fwd_create() - Create a new GPIO forwarder
420 * @dev: Parent device pointer
421 * @ngpios: Number of GPIOs in the forwarder.
422 * @descs: Array containing the GPIO descriptors to forward to.
423 * This array must contain @ngpios entries, and must not be deallocated
424 * before the forwarder has been destroyed again.
426 * This function creates a new gpiochip, which forwards all GPIO operations to
427 * the passed GPIO descriptors.
429 * Return: An opaque object pointer, or an ERR_PTR()-encoded negative error
432 static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
434 struct gpio_desc *descs[])
436 const char *label = dev_name(dev);
437 struct gpiochip_fwd *fwd;
438 struct gpio_chip *chip;
442 fwd = devm_kzalloc(dev, struct_size(fwd, tmp,
443 BITS_TO_LONGS(ngpios) + ngpios), GFP_KERNEL);
445 return ERR_PTR(-ENOMEM);
450 * If any of the GPIO lines are sleeping, then the entire forwarder
452 * If any of the chips support .set_config(), then the forwarder will
453 * support setting configs.
455 for (i = 0; i < ngpios; i++) {
456 struct gpio_chip *parent = gpiod_to_chip(descs[i]);
458 dev_dbg(dev, "%u => gpio-%d\n", i, desc_to_gpio(descs[i]));
460 if (gpiod_cansleep(descs[i]))
461 chip->can_sleep = true;
462 if (parent && parent->set_config)
463 chip->set_config = gpio_fwd_set_config;
468 chip->owner = THIS_MODULE;
469 chip->get_direction = gpio_fwd_get_direction;
470 chip->direction_input = gpio_fwd_direction_input;
471 chip->direction_output = gpio_fwd_direction_output;
472 chip->get = gpio_fwd_get;
473 chip->get_multiple = gpio_fwd_get_multiple;
474 chip->set = gpio_fwd_set;
475 chip->set_multiple = gpio_fwd_set_multiple;
477 chip->ngpio = ngpios;
481 mutex_init(&fwd->mlock);
483 spin_lock_init(&fwd->slock);
485 error = devm_gpiochip_add_data(dev, chip, fwd);
487 return ERR_PTR(error);
494 * GPIO Aggregator platform device
497 static int gpio_aggregator_probe(struct platform_device *pdev)
499 struct device *dev = &pdev->dev;
500 struct gpio_desc **descs;
501 struct gpiochip_fwd *fwd;
504 n = gpiod_count(dev, NULL);
508 descs = devm_kmalloc_array(dev, n, sizeof(*descs), GFP_KERNEL);
512 for (i = 0; i < n; i++) {
513 descs[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
514 if (IS_ERR(descs[i]))
515 return PTR_ERR(descs[i]);
518 fwd = gpiochip_fwd_create(dev, n, descs);
522 platform_set_drvdata(pdev, fwd);
527 static const struct of_device_id gpio_aggregator_dt_ids[] = {
529 * Add GPIO-operated devices controlled from userspace below,
530 * or use "driver_override" in sysfs
534 MODULE_DEVICE_TABLE(of, gpio_aggregator_dt_ids);
537 static struct platform_driver gpio_aggregator_driver = {
538 .probe = gpio_aggregator_probe,
541 .groups = gpio_aggregator_groups,
542 .of_match_table = of_match_ptr(gpio_aggregator_dt_ids),
546 static int __init gpio_aggregator_init(void)
548 return platform_driver_register(&gpio_aggregator_driver);
550 module_init(gpio_aggregator_init);
552 static void __exit gpio_aggregator_exit(void)
554 gpio_aggregator_remove_all();
555 platform_driver_unregister(&gpio_aggregator_driver);
557 module_exit(gpio_aggregator_exit);
559 MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
560 MODULE_DESCRIPTION("GPIO Aggregator");
561 MODULE_LICENSE("GPL v2");