1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/anon_inodes.h>
4 #include <linux/atomic.h>
5 #include <linux/bitmap.h>
6 #include <linux/build_bug.h>
7 #include <linux/cdev.h>
8 #include <linux/compat.h>
9 #include <linux/compiler.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/file.h>
13 #include <linux/gpio.h>
14 #include <linux/gpio/driver.h>
15 #include <linux/interrupt.h>
16 #include <linux/irqreturn.h>
17 #include <linux/kernel.h>
18 #include <linux/kfifo.h>
19 #include <linux/module.h>
20 #include <linux/mutex.h>
21 #include <linux/pinctrl/consumer.h>
22 #include <linux/poll.h>
23 #include <linux/spinlock.h>
24 #include <linux/timekeeping.h>
25 #include <linux/uaccess.h>
26 #include <linux/workqueue.h>
27 #include <uapi/linux/gpio.h>
30 #include "gpiolib-cdev.h"
33 * Array sizes must ensure 64-bit alignment and not create holes in the
36 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
37 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
40 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
42 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
43 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
44 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
45 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
46 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
47 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
51 /* Character device interface to GPIO.
53 * The GPIO character device, /dev/gpiochipN, provides userspace an
54 * interface to gpiolib GPIOs via ioctl()s.
58 * GPIO line handle management
61 #ifdef CONFIG_GPIO_CDEV_V1
63 * struct linehandle_state - contains the state of a userspace handle
64 * @gdev: the GPIO device the handle pertains to
65 * @label: consumer label used to tag descriptors
66 * @descs: the GPIO descriptors held by this handle
67 * @num_descs: the number of descriptors held in the descs array
69 struct linehandle_state {
70 struct gpio_device *gdev;
72 struct gpio_desc *descs[GPIOHANDLES_MAX];
76 #define GPIOHANDLE_REQUEST_VALID_FLAGS \
77 (GPIOHANDLE_REQUEST_INPUT | \
78 GPIOHANDLE_REQUEST_OUTPUT | \
79 GPIOHANDLE_REQUEST_ACTIVE_LOW | \
80 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
81 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
82 GPIOHANDLE_REQUEST_BIAS_DISABLE | \
83 GPIOHANDLE_REQUEST_OPEN_DRAIN | \
84 GPIOHANDLE_REQUEST_OPEN_SOURCE)
86 static int linehandle_validate_flags(u32 flags)
88 /* Return an error if an unknown flag is set */
89 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
93 * Do not allow both INPUT & OUTPUT flags to be set as they are
96 if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
97 (flags & GPIOHANDLE_REQUEST_OUTPUT))
101 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
102 * the hardware actually supports enabling both at the same time the
103 * electrical result would be disastrous.
105 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
106 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
109 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
110 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
111 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
112 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
115 /* Bias flags only allowed for input or output mode. */
116 if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
117 (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
118 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
119 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
120 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
123 /* Only one bias flag can be set. */
124 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
125 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
126 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
127 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
128 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
134 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
136 assign_bit(FLAG_ACTIVE_LOW, flagsp,
137 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
138 assign_bit(FLAG_OPEN_DRAIN, flagsp,
139 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
140 assign_bit(FLAG_OPEN_SOURCE, flagsp,
141 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
142 assign_bit(FLAG_PULL_UP, flagsp,
143 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
144 assign_bit(FLAG_PULL_DOWN, flagsp,
145 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
146 assign_bit(FLAG_BIAS_DISABLE, flagsp,
147 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
150 static long linehandle_set_config(struct linehandle_state *lh,
153 struct gpiohandle_config gcnf;
154 struct gpio_desc *desc;
158 if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
162 ret = linehandle_validate_flags(lflags);
166 for (i = 0; i < lh->num_descs; i++) {
168 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
171 * Lines have to be requested explicitly for input
172 * or output, else the line will be treated "as is".
174 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
175 int val = !!gcnf.default_values[i];
177 ret = gpiod_direction_output(desc, val);
180 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
181 ret = gpiod_direction_input(desc);
186 blocking_notifier_call_chain(&desc->gdev->notifier,
187 GPIO_V2_LINE_CHANGED_CONFIG,
193 static long linehandle_ioctl(struct file *file, unsigned int cmd,
196 struct linehandle_state *lh = file->private_data;
197 void __user *ip = (void __user *)arg;
198 struct gpiohandle_data ghd;
199 DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
202 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
203 /* NOTE: It's ok to read values of output lines. */
204 int ret = gpiod_get_array_value_complex(false,
213 memset(&ghd, 0, sizeof(ghd));
214 for (i = 0; i < lh->num_descs; i++)
215 ghd.values[i] = test_bit(i, vals);
217 if (copy_to_user(ip, &ghd, sizeof(ghd)))
221 } else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) {
223 * All line descriptors were created at once with the same
224 * flags so just check if the first one is really output.
226 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
229 if (copy_from_user(&ghd, ip, sizeof(ghd)))
232 /* Clamp all values to [0,1] */
233 for (i = 0; i < lh->num_descs; i++)
234 __assign_bit(i, vals, ghd.values[i]);
236 /* Reuse the array setting function */
237 return gpiod_set_array_value_complex(false,
243 } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) {
244 return linehandle_set_config(lh, ip);
250 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
253 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
257 static void linehandle_free(struct linehandle_state *lh)
261 for (i = 0; i < lh->num_descs; i++)
263 gpiod_free(lh->descs[i]);
265 put_device(&lh->gdev->dev);
269 static int linehandle_release(struct inode *inode, struct file *file)
271 linehandle_free(file->private_data);
275 static const struct file_operations linehandle_fileops = {
276 .release = linehandle_release,
277 .owner = THIS_MODULE,
278 .llseek = noop_llseek,
279 .unlocked_ioctl = linehandle_ioctl,
281 .compat_ioctl = linehandle_ioctl_compat,
285 static int linehandle_create(struct gpio_device *gdev, void __user *ip)
287 struct gpiohandle_request handlereq;
288 struct linehandle_state *lh;
293 if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
295 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
298 lflags = handlereq.flags;
300 ret = linehandle_validate_flags(lflags);
304 lh = kzalloc(sizeof(*lh), GFP_KERNEL);
308 get_device(&gdev->dev);
310 if (handlereq.consumer_label[0] != '\0') {
311 /* label is only initialized if consumer_label is set */
312 lh->label = kstrndup(handlereq.consumer_label,
313 sizeof(handlereq.consumer_label) - 1,
321 lh->num_descs = handlereq.lines;
323 /* Request each GPIO */
324 for (i = 0; i < handlereq.lines; i++) {
325 u32 offset = handlereq.lineoffsets[i];
326 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
333 ret = gpiod_request(desc, lh->label);
337 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
339 ret = gpiod_set_transitory(desc, false);
344 * Lines have to be requested explicitly for input
345 * or output, else the line will be treated "as is".
347 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
348 int val = !!handlereq.default_values[i];
350 ret = gpiod_direction_output(desc, val);
353 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
354 ret = gpiod_direction_input(desc);
359 blocking_notifier_call_chain(&desc->gdev->notifier,
360 GPIO_V2_LINE_CHANGED_REQUESTED, desc);
362 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
366 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
372 file = anon_inode_getfile("gpio-linehandle",
375 O_RDONLY | O_CLOEXEC);
378 goto out_put_unused_fd;
382 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
384 * fput() will trigger the release() callback, so do not go onto
385 * the regular error cleanup path here.
392 fd_install(fd, file);
394 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
405 #endif /* CONFIG_GPIO_CDEV_V1 */
408 * struct line - contains the state of a requested line
409 * @desc: the GPIO descriptor for this line.
410 * @req: the corresponding line request
411 * @irq: the interrupt triggered in response to events on this GPIO
412 * @eflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
413 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
414 * @timestamp_ns: cache for the timestamp storing it between hardirq and
415 * IRQ thread, used to bring the timestamp close to the actual event
416 * @req_seqno: the seqno for the current edge event in the sequence of
417 * events for the corresponding line request. This is drawn from the @req.
418 * @line_seqno: the seqno for the current edge event in the sequence of
419 * events for this line.
420 * @work: the worker that implements software debouncing
421 * @sw_debounced: flag indicating if the software debouncer is active
422 * @level: the current debounced physical level of the line
425 struct gpio_desc *desc;
427 * -- edge detector specific fields --
433 * timestamp_ns and req_seqno are accessed only by
434 * edge_irq_handler() and edge_irq_thread(), which are themselves
435 * mutually exclusive, so no additional protection is necessary.
440 * line_seqno is accessed by either edge_irq_thread() or
441 * debounce_work_func(), which are themselves mutually exclusive,
442 * so no additional protection is necessary.
446 * -- debouncer specific fields --
448 struct delayed_work work;
450 * sw_debounce is accessed by linereq_set_config(), which is the
451 * only setter, and linereq_get_values(), which can live with a
452 * slightly stale value.
454 unsigned int sw_debounced;
456 * level is accessed by debounce_work_func(), which is the only
457 * setter, and linereq_get_values() which can live with a slightly
464 * struct linereq - contains the state of a userspace line request
465 * @gdev: the GPIO device the line request pertains to
466 * @label: consumer label used to tag GPIO descriptors
467 * @num_lines: the number of lines in the lines array
468 * @wait: wait queue that handles blocking reads of events
469 * @event_buffer_size: the number of elements allocated in @events
470 * @events: KFIFO for the GPIO events
471 * @seqno: the sequence number for edge events generated on all lines in
472 * this line request. Note that this is not used when @num_lines is 1, as
473 * the line_seqno is then the same and is cheaper to calculate.
474 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
475 * of configuration, particularly multi-step accesses to desc flags.
476 * @lines: the lines held by this line request, with @num_lines elements.
479 struct gpio_device *gdev;
482 wait_queue_head_t wait;
483 u32 event_buffer_size;
484 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
486 struct mutex config_mutex;
490 #define GPIO_V2_LINE_BIAS_FLAGS \
491 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
492 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
493 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
495 #define GPIO_V2_LINE_DIRECTION_FLAGS \
496 (GPIO_V2_LINE_FLAG_INPUT | \
497 GPIO_V2_LINE_FLAG_OUTPUT)
499 #define GPIO_V2_LINE_DRIVE_FLAGS \
500 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
501 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
503 #define GPIO_V2_LINE_EDGE_FLAGS \
504 (GPIO_V2_LINE_FLAG_EDGE_RISING | \
505 GPIO_V2_LINE_FLAG_EDGE_FALLING)
507 #define GPIO_V2_LINE_VALID_FLAGS \
508 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
509 GPIO_V2_LINE_DIRECTION_FLAGS | \
510 GPIO_V2_LINE_DRIVE_FLAGS | \
511 GPIO_V2_LINE_EDGE_FLAGS | \
512 GPIO_V2_LINE_BIAS_FLAGS)
514 static void linereq_put_event(struct linereq *lr,
515 struct gpio_v2_line_event *le)
517 bool overflow = false;
519 spin_lock(&lr->wait.lock);
520 if (kfifo_is_full(&lr->events)) {
522 kfifo_skip(&lr->events);
524 kfifo_in(&lr->events, le, 1);
525 spin_unlock(&lr->wait.lock);
527 wake_up_poll(&lr->wait, EPOLLIN);
529 pr_debug_ratelimited("event FIFO is full - event dropped\n");
532 static irqreturn_t edge_irq_thread(int irq, void *p)
534 struct line *line = p;
535 struct linereq *lr = line->req;
536 struct gpio_v2_line_event le;
538 /* Do not leak kernel stack to userspace */
539 memset(&le, 0, sizeof(le));
541 if (line->timestamp_ns) {
542 le.timestamp_ns = line->timestamp_ns;
545 * We may be running from a nested threaded interrupt in
546 * which case we didn't get the timestamp from
547 * edge_irq_handler().
549 le.timestamp_ns = ktime_get_ns();
550 if (lr->num_lines != 1)
551 line->req_seqno = atomic_inc_return(&lr->seqno);
553 line->timestamp_ns = 0;
555 if (line->eflags == (GPIO_V2_LINE_FLAG_EDGE_RISING |
556 GPIO_V2_LINE_FLAG_EDGE_FALLING)) {
557 int level = gpiod_get_value_cansleep(line->desc);
560 /* Emit low-to-high event */
561 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
563 /* Emit high-to-low event */
564 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
565 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) {
566 /* Emit low-to-high event */
567 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
568 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) {
569 /* Emit high-to-low event */
570 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
575 le.line_seqno = line->line_seqno;
576 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
577 le.offset = gpio_chip_hwgpio(line->desc);
579 linereq_put_event(lr, &le);
584 static irqreturn_t edge_irq_handler(int irq, void *p)
586 struct line *line = p;
587 struct linereq *lr = line->req;
590 * Just store the timestamp in hardirq context so we get it as
591 * close in time as possible to the actual event.
593 line->timestamp_ns = ktime_get_ns();
595 if (lr->num_lines != 1)
596 line->req_seqno = atomic_inc_return(&lr->seqno);
598 return IRQ_WAKE_THREAD;
602 * returns the current debounced logical value.
604 static bool debounced_value(struct line *line)
609 * minor race - debouncer may be stopped here, so edge_detector_stop()
610 * must leave the value unchanged so the following will read the level
611 * from when the debouncer was last running.
613 value = READ_ONCE(line->level);
615 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
621 static irqreturn_t debounce_irq_handler(int irq, void *p)
623 struct line *line = p;
625 mod_delayed_work(system_wq, &line->work,
626 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
631 static void debounce_work_func(struct work_struct *work)
633 struct gpio_v2_line_event le;
634 struct line *line = container_of(work, struct line, work.work);
638 level = gpiod_get_raw_value_cansleep(line->desc);
640 pr_debug_ratelimited("debouncer failed to read line value\n");
644 if (READ_ONCE(line->level) == level)
647 WRITE_ONCE(line->level, level);
649 /* -- edge detection -- */
653 /* switch from physical level to logical - if they differ */
654 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
657 /* ignore edges that are not being monitored */
658 if (((line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
659 ((line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
662 /* Do not leak kernel stack to userspace */
663 memset(&le, 0, sizeof(le));
666 le.timestamp_ns = ktime_get_ns();
667 le.offset = gpio_chip_hwgpio(line->desc);
669 le.line_seqno = line->line_seqno;
670 le.seqno = (lr->num_lines == 1) ?
671 le.line_seqno : atomic_inc_return(&lr->seqno);
674 /* Emit low-to-high event */
675 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
677 /* Emit high-to-low event */
678 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
680 linereq_put_event(lr, &le);
683 static int debounce_setup(struct line *line,
684 unsigned int debounce_period_us)
686 unsigned long irqflags;
690 ret = gpiod_set_debounce(line->desc, debounce_period_us);
692 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
695 if (ret != -ENOTSUPP)
698 if (debounce_period_us) {
699 /* setup software debounce */
700 level = gpiod_get_raw_value_cansleep(line->desc);
704 irq = gpiod_to_irq(line->desc);
708 WRITE_ONCE(line->level, level);
709 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
710 ret = request_irq(irq, debounce_irq_handler, irqflags,
711 line->req->label, line);
715 WRITE_ONCE(line->sw_debounced, 1);
721 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
722 unsigned int line_idx)
725 u64 mask = BIT_ULL(line_idx);
727 for (i = 0; i < lc->num_attrs; i++) {
728 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
729 (lc->attrs[i].mask & mask))
735 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
736 unsigned int line_idx)
739 u64 mask = BIT_ULL(line_idx);
741 for (i = 0; i < lc->num_attrs; i++) {
742 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
743 (lc->attrs[i].mask & mask))
744 return lc->attrs[i].attr.debounce_period_us;
749 static void edge_detector_stop(struct line *line)
752 free_irq(line->irq, line);
756 cancel_delayed_work_sync(&line->work);
757 WRITE_ONCE(line->sw_debounced, 0);
759 /* do not change line->level - see comment in debounced_value() */
762 static int edge_detector_setup(struct line *line,
763 struct gpio_v2_line_config *lc,
764 unsigned int line_idx,
767 u32 debounce_period_us;
768 unsigned long irqflags = 0;
771 if (eflags && !kfifo_initialized(&line->req->events)) {
772 ret = kfifo_alloc(&line->req->events,
773 line->req->event_buffer_size, GFP_KERNEL);
777 line->eflags = eflags;
778 if (gpio_v2_line_config_debounced(lc, line_idx)) {
779 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
780 ret = debounce_setup(line, debounce_period_us);
783 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
786 /* detection disabled or sw debouncer will provide edge detection */
787 if (!eflags || READ_ONCE(line->sw_debounced))
790 irq = gpiod_to_irq(line->desc);
794 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
795 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
796 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
797 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
798 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
799 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
800 irqflags |= IRQF_ONESHOT;
802 /* Request a thread to read the events */
803 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
804 irqflags, line->req->label, line);
812 static int edge_detector_update(struct line *line,
813 struct gpio_v2_line_config *lc,
814 unsigned int line_idx,
815 u64 eflags, bool polarity_change)
817 unsigned int debounce_period_us =
818 gpio_v2_line_config_debounce_period(lc, line_idx);
820 if ((line->eflags == eflags) && !polarity_change &&
821 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
824 /* sw debounced and still will be...*/
825 if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
826 line->eflags = eflags;
827 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
831 /* reconfiguring edge detection or sw debounce being disabled */
832 if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
833 (!debounce_period_us && READ_ONCE(line->sw_debounced)))
834 edge_detector_stop(line);
836 return edge_detector_setup(line, lc, line_idx, eflags);
839 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
840 unsigned int line_idx)
843 u64 mask = BIT_ULL(line_idx);
845 for (i = 0; i < lc->num_attrs; i++) {
846 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
847 (lc->attrs[i].mask & mask))
848 return lc->attrs[i].attr.flags;
853 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
854 unsigned int line_idx)
857 u64 mask = BIT_ULL(line_idx);
859 for (i = 0; i < lc->num_attrs; i++) {
860 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
861 (lc->attrs[i].mask & mask))
862 return !!(lc->attrs[i].attr.values & mask);
867 static int gpio_v2_line_flags_validate(u64 flags)
869 /* Return an error if an unknown flag is set */
870 if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
874 * Do not allow both INPUT and OUTPUT flags to be set as they are
877 if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
878 (flags & GPIO_V2_LINE_FLAG_OUTPUT))
881 /* Edge detection requires explicit input. */
882 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
883 !(flags & GPIO_V2_LINE_FLAG_INPUT))
887 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
888 * request. If the hardware actually supports enabling both at the
889 * same time the electrical result would be disastrous.
891 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
892 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
895 /* Drive requires explicit output direction. */
896 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
897 !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
900 /* Bias requires explicit direction. */
901 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
902 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
905 /* Only one bias flag can be set. */
906 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
907 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
908 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
909 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
910 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
916 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
917 unsigned int num_lines)
923 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
926 if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
929 for (i = 0; i < num_lines; i++) {
930 flags = gpio_v2_line_config_flags(lc, i);
931 ret = gpio_v2_line_flags_validate(flags);
935 /* debounce requires explicit input */
936 if (gpio_v2_line_config_debounced(lc, i) &&
937 !(flags & GPIO_V2_LINE_FLAG_INPUT))
943 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
944 unsigned long *flagsp)
946 assign_bit(FLAG_ACTIVE_LOW, flagsp,
947 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
949 if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
950 set_bit(FLAG_IS_OUT, flagsp);
951 else if (flags & GPIO_V2_LINE_FLAG_INPUT)
952 clear_bit(FLAG_IS_OUT, flagsp);
954 assign_bit(FLAG_EDGE_RISING, flagsp,
955 flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
956 assign_bit(FLAG_EDGE_FALLING, flagsp,
957 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
959 assign_bit(FLAG_OPEN_DRAIN, flagsp,
960 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
961 assign_bit(FLAG_OPEN_SOURCE, flagsp,
962 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
964 assign_bit(FLAG_PULL_UP, flagsp,
965 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
966 assign_bit(FLAG_PULL_DOWN, flagsp,
967 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
968 assign_bit(FLAG_BIAS_DISABLE, flagsp,
969 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
972 static long linereq_get_values(struct linereq *lr, void __user *ip)
974 struct gpio_v2_line_values lv;
975 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
976 struct gpio_desc **descs;
977 unsigned int i, didx, num_get;
981 /* NOTE: It's ok to read values of output lines. */
982 if (copy_from_user(&lv, ip, sizeof(lv)))
985 for (num_get = 0, i = 0; i < lr->num_lines; i++) {
986 if (lv.mask & BIT_ULL(i)) {
988 descs = &lr->lines[i].desc;
996 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
999 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1000 if (lv.mask & BIT_ULL(i)) {
1001 descs[didx] = lr->lines[i].desc;
1006 ret = gpiod_get_array_value_complex(false, true, num_get,
1015 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1016 if (lv.mask & BIT_ULL(i)) {
1017 if (lr->lines[i].sw_debounced)
1018 val = debounced_value(&lr->lines[i]);
1020 val = test_bit(didx, vals);
1022 lv.bits |= BIT_ULL(i);
1027 if (copy_to_user(ip, &lv, sizeof(lv)))
1033 static long linereq_set_values_unlocked(struct linereq *lr,
1034 struct gpio_v2_line_values *lv)
1036 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1037 struct gpio_desc **descs;
1038 unsigned int i, didx, num_set;
1041 bitmap_zero(vals, GPIO_V2_LINES_MAX);
1042 for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1043 if (lv->mask & BIT_ULL(i)) {
1044 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
1046 if (lv->bits & BIT_ULL(i))
1047 __set_bit(num_set, vals);
1049 descs = &lr->lines[i].desc;
1056 /* build compacted desc array and values */
1057 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
1060 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1061 if (lv->mask & BIT_ULL(i)) {
1062 descs[didx] = lr->lines[i].desc;
1067 ret = gpiod_set_array_value_complex(false, true, num_set,
1075 static long linereq_set_values(struct linereq *lr, void __user *ip)
1077 struct gpio_v2_line_values lv;
1080 if (copy_from_user(&lv, ip, sizeof(lv)))
1083 mutex_lock(&lr->config_mutex);
1085 ret = linereq_set_values_unlocked(lr, &lv);
1087 mutex_unlock(&lr->config_mutex);
1092 static long linereq_set_config_unlocked(struct linereq *lr,
1093 struct gpio_v2_line_config *lc)
1095 struct gpio_desc *desc;
1098 bool polarity_change;
1101 for (i = 0; i < lr->num_lines; i++) {
1102 desc = lr->lines[i].desc;
1103 flags = gpio_v2_line_config_flags(lc, i);
1105 (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) !=
1106 ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0));
1108 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1110 * Lines have to be requested explicitly for input
1111 * or output, else the line will be treated "as is".
1113 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1114 int val = gpio_v2_line_config_output_value(lc, i);
1116 edge_detector_stop(&lr->lines[i]);
1117 ret = gpiod_direction_output(desc, val);
1120 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1121 ret = gpiod_direction_input(desc);
1125 ret = edge_detector_update(&lr->lines[i], lc, i,
1126 flags & GPIO_V2_LINE_EDGE_FLAGS,
1132 blocking_notifier_call_chain(&desc->gdev->notifier,
1133 GPIO_V2_LINE_CHANGED_CONFIG,
1139 static long linereq_set_config(struct linereq *lr, void __user *ip)
1141 struct gpio_v2_line_config lc;
1144 if (copy_from_user(&lc, ip, sizeof(lc)))
1147 ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1151 mutex_lock(&lr->config_mutex);
1153 ret = linereq_set_config_unlocked(lr, &lc);
1155 mutex_unlock(&lr->config_mutex);
1160 static long linereq_ioctl(struct file *file, unsigned int cmd,
1163 struct linereq *lr = file->private_data;
1164 void __user *ip = (void __user *)arg;
1166 if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
1167 return linereq_get_values(lr, ip);
1168 else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL)
1169 return linereq_set_values(lr, ip);
1170 else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
1171 return linereq_set_config(lr, ip);
1176 #ifdef CONFIG_COMPAT
1177 static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1180 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1184 static __poll_t linereq_poll(struct file *file,
1185 struct poll_table_struct *wait)
1187 struct linereq *lr = file->private_data;
1188 __poll_t events = 0;
1190 poll_wait(file, &lr->wait, wait);
1192 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1194 events = EPOLLIN | EPOLLRDNORM;
1199 static ssize_t linereq_read(struct file *file,
1204 struct linereq *lr = file->private_data;
1205 struct gpio_v2_line_event le;
1206 ssize_t bytes_read = 0;
1209 if (count < sizeof(le))
1213 spin_lock(&lr->wait.lock);
1214 if (kfifo_is_empty(&lr->events)) {
1216 spin_unlock(&lr->wait.lock);
1220 if (file->f_flags & O_NONBLOCK) {
1221 spin_unlock(&lr->wait.lock);
1225 ret = wait_event_interruptible_locked(lr->wait,
1226 !kfifo_is_empty(&lr->events));
1228 spin_unlock(&lr->wait.lock);
1233 ret = kfifo_out(&lr->events, &le, 1);
1234 spin_unlock(&lr->wait.lock);
1237 * This should never happen - we were holding the
1238 * lock from the moment we learned the fifo is no
1239 * longer empty until now.
1245 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1247 bytes_read += sizeof(le);
1248 } while (count >= bytes_read + sizeof(le));
1253 static void linereq_free(struct linereq *lr)
1257 for (i = 0; i < lr->num_lines; i++) {
1258 edge_detector_stop(&lr->lines[i]);
1259 if (lr->lines[i].desc)
1260 gpiod_free(lr->lines[i].desc);
1262 kfifo_free(&lr->events);
1264 put_device(&lr->gdev->dev);
1268 static int linereq_release(struct inode *inode, struct file *file)
1270 struct linereq *lr = file->private_data;
1276 static const struct file_operations line_fileops = {
1277 .release = linereq_release,
1278 .read = linereq_read,
1279 .poll = linereq_poll,
1280 .owner = THIS_MODULE,
1281 .llseek = noop_llseek,
1282 .unlocked_ioctl = linereq_ioctl,
1283 #ifdef CONFIG_COMPAT
1284 .compat_ioctl = linereq_ioctl_compat,
1288 static int linereq_create(struct gpio_device *gdev, void __user *ip)
1290 struct gpio_v2_line_request ulr;
1291 struct gpio_v2_line_config *lc;
1298 if (copy_from_user(&ulr, ip, sizeof(ulr)))
1301 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1304 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
1308 ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1312 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
1317 get_device(&gdev->dev);
1319 for (i = 0; i < ulr.num_lines; i++) {
1320 lr->lines[i].req = lr;
1321 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1322 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1325 if (ulr.consumer[0] != '\0') {
1326 /* label is only initialized if consumer is set */
1327 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1331 goto out_free_linereq;
1335 mutex_init(&lr->config_mutex);
1336 init_waitqueue_head(&lr->wait);
1337 lr->event_buffer_size = ulr.event_buffer_size;
1338 if (lr->event_buffer_size == 0)
1339 lr->event_buffer_size = ulr.num_lines * 16;
1340 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1341 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1343 atomic_set(&lr->seqno, 0);
1344 lr->num_lines = ulr.num_lines;
1346 /* Request each GPIO */
1347 for (i = 0; i < ulr.num_lines; i++) {
1348 u32 offset = ulr.offsets[i];
1349 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
1352 ret = PTR_ERR(desc);
1353 goto out_free_linereq;
1356 ret = gpiod_request(desc, lr->label);
1358 goto out_free_linereq;
1360 lr->lines[i].desc = desc;
1361 flags = gpio_v2_line_config_flags(lc, i);
1362 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1364 ret = gpiod_set_transitory(desc, false);
1366 goto out_free_linereq;
1369 * Lines have to be requested explicitly for input
1370 * or output, else the line will be treated "as is".
1372 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1373 int val = gpio_v2_line_config_output_value(lc, i);
1375 ret = gpiod_direction_output(desc, val);
1377 goto out_free_linereq;
1378 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1379 ret = gpiod_direction_input(desc);
1381 goto out_free_linereq;
1383 ret = edge_detector_setup(&lr->lines[i], lc, i,
1384 flags & GPIO_V2_LINE_EDGE_FLAGS);
1386 goto out_free_linereq;
1389 blocking_notifier_call_chain(&desc->gdev->notifier,
1390 GPIO_V2_LINE_CHANGED_REQUESTED, desc);
1392 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1396 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1399 goto out_free_linereq;
1402 file = anon_inode_getfile("gpio-line", &line_fileops, lr,
1403 O_RDONLY | O_CLOEXEC);
1405 ret = PTR_ERR(file);
1406 goto out_put_unused_fd;
1410 if (copy_to_user(ip, &ulr, sizeof(ulr))) {
1412 * fput() will trigger the release() callback, so do not go onto
1413 * the regular error cleanup path here.
1420 fd_install(fd, file);
1422 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1434 #ifdef CONFIG_GPIO_CDEV_V1
1437 * GPIO line event management
1441 * struct lineevent_state - contains the state of a userspace event
1442 * @gdev: the GPIO device the event pertains to
1443 * @label: consumer label used to tag descriptors
1444 * @desc: the GPIO descriptor held by this event
1445 * @eflags: the event flags this line was requested with
1446 * @irq: the interrupt that trigger in response to events on this GPIO
1447 * @wait: wait queue that handles blocking reads of events
1448 * @events: KFIFO for the GPIO events
1449 * @timestamp: cache for the timestamp storing it between hardirq
1450 * and IRQ thread, used to bring the timestamp close to the actual
1453 struct lineevent_state {
1454 struct gpio_device *gdev;
1456 struct gpio_desc *desc;
1459 wait_queue_head_t wait;
1460 DECLARE_KFIFO(events, struct gpioevent_data, 16);
1464 #define GPIOEVENT_REQUEST_VALID_FLAGS \
1465 (GPIOEVENT_REQUEST_RISING_EDGE | \
1466 GPIOEVENT_REQUEST_FALLING_EDGE)
1468 static __poll_t lineevent_poll(struct file *file,
1469 struct poll_table_struct *wait)
1471 struct lineevent_state *le = file->private_data;
1472 __poll_t events = 0;
1474 poll_wait(file, &le->wait, wait);
1476 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1477 events = EPOLLIN | EPOLLRDNORM;
1482 static ssize_t lineevent_get_size(void)
1484 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
1485 /* i386 has no padding after 'id' */
1486 if (in_ia32_syscall()) {
1487 struct compat_gpioeevent_data {
1488 compat_u64 timestamp;
1492 return sizeof(struct compat_gpioeevent_data);
1495 return sizeof(struct gpioevent_data);
1498 static ssize_t lineevent_read(struct file *file,
1503 struct lineevent_state *le = file->private_data;
1504 struct gpioevent_data ge;
1505 ssize_t bytes_read = 0;
1510 * When compatible system call is being used the struct gpioevent_data,
1511 * in case of at least ia32, has different size due to the alignment
1512 * differences. Because we have first member 64 bits followed by one of
1513 * 32 bits there is no gap between them. The only difference is the
1514 * padding at the end of the data structure. Hence, we calculate the
1515 * actual sizeof() and pass this as an argument to copy_to_user() to
1516 * drop unneeded bytes from the output.
1518 ge_size = lineevent_get_size();
1519 if (count < ge_size)
1523 spin_lock(&le->wait.lock);
1524 if (kfifo_is_empty(&le->events)) {
1526 spin_unlock(&le->wait.lock);
1530 if (file->f_flags & O_NONBLOCK) {
1531 spin_unlock(&le->wait.lock);
1535 ret = wait_event_interruptible_locked(le->wait,
1536 !kfifo_is_empty(&le->events));
1538 spin_unlock(&le->wait.lock);
1543 ret = kfifo_out(&le->events, &ge, 1);
1544 spin_unlock(&le->wait.lock);
1547 * This should never happen - we were holding the lock
1548 * from the moment we learned the fifo is no longer
1555 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1557 bytes_read += ge_size;
1558 } while (count >= bytes_read + ge_size);
1563 static void lineevent_free(struct lineevent_state *le)
1566 free_irq(le->irq, le);
1568 gpiod_free(le->desc);
1570 put_device(&le->gdev->dev);
1574 static int lineevent_release(struct inode *inode, struct file *file)
1576 lineevent_free(file->private_data);
1580 static long lineevent_ioctl(struct file *file, unsigned int cmd,
1583 struct lineevent_state *le = file->private_data;
1584 void __user *ip = (void __user *)arg;
1585 struct gpiohandle_data ghd;
1588 * We can get the value for an event line but not set it,
1589 * because it is input by definition.
1591 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
1594 memset(&ghd, 0, sizeof(ghd));
1596 val = gpiod_get_value_cansleep(le->desc);
1599 ghd.values[0] = val;
1601 if (copy_to_user(ip, &ghd, sizeof(ghd)))
1609 #ifdef CONFIG_COMPAT
1610 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
1613 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1617 static const struct file_operations lineevent_fileops = {
1618 .release = lineevent_release,
1619 .read = lineevent_read,
1620 .poll = lineevent_poll,
1621 .owner = THIS_MODULE,
1622 .llseek = noop_llseek,
1623 .unlocked_ioctl = lineevent_ioctl,
1624 #ifdef CONFIG_COMPAT
1625 .compat_ioctl = lineevent_ioctl_compat,
1629 static irqreturn_t lineevent_irq_thread(int irq, void *p)
1631 struct lineevent_state *le = p;
1632 struct gpioevent_data ge;
1635 /* Do not leak kernel stack to userspace */
1636 memset(&ge, 0, sizeof(ge));
1639 * We may be running from a nested threaded interrupt in which case
1640 * we didn't get the timestamp from lineevent_irq_handler().
1643 ge.timestamp = ktime_get_ns();
1645 ge.timestamp = le->timestamp;
1647 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
1648 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1649 int level = gpiod_get_value_cansleep(le->desc);
1652 /* Emit low-to-high event */
1653 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1655 /* Emit high-to-low event */
1656 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1657 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
1658 /* Emit low-to-high event */
1659 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1660 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1661 /* Emit high-to-low event */
1662 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1667 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
1670 wake_up_poll(&le->wait, EPOLLIN);
1672 pr_debug_ratelimited("event FIFO is full - event dropped\n");
1677 static irqreturn_t lineevent_irq_handler(int irq, void *p)
1679 struct lineevent_state *le = p;
1682 * Just store the timestamp in hardirq context so we get it as
1683 * close in time as possible to the actual event.
1685 le->timestamp = ktime_get_ns();
1687 return IRQ_WAKE_THREAD;
1690 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
1692 struct gpioevent_request eventreq;
1693 struct lineevent_state *le;
1694 struct gpio_desc *desc;
1701 int irq, irqflags = 0;
1703 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
1706 offset = eventreq.lineoffset;
1707 lflags = eventreq.handleflags;
1708 eflags = eventreq.eventflags;
1710 desc = gpiochip_get_desc(gdev->chip, offset);
1712 return PTR_ERR(desc);
1714 /* Return an error if a unknown flag is set */
1715 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
1716 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
1719 /* This is just wrong: we don't look for events on output lines */
1720 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
1721 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
1722 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
1725 /* Only one bias flag can be set. */
1726 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
1727 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
1728 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
1729 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
1730 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
1733 le = kzalloc(sizeof(*le), GFP_KERNEL);
1737 get_device(&gdev->dev);
1739 if (eventreq.consumer_label[0] != '\0') {
1740 /* label is only initialized if consumer_label is set */
1741 le->label = kstrndup(eventreq.consumer_label,
1742 sizeof(eventreq.consumer_label) - 1,
1750 ret = gpiod_request(desc, le->label);
1754 le->eflags = eflags;
1756 linehandle_flags_to_desc_flags(lflags, &desc->flags);
1758 ret = gpiod_direction_input(desc);
1762 blocking_notifier_call_chain(&desc->gdev->notifier,
1763 GPIO_V2_LINE_CHANGED_REQUESTED, desc);
1765 irq = gpiod_to_irq(desc);
1772 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
1773 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
1774 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1775 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
1776 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
1777 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1778 irqflags |= IRQF_ONESHOT;
1780 INIT_KFIFO(le->events);
1781 init_waitqueue_head(&le->wait);
1783 /* Request a thread to read the events */
1784 ret = request_threaded_irq(le->irq,
1785 lineevent_irq_handler,
1786 lineevent_irq_thread,
1793 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1799 file = anon_inode_getfile("gpio-event",
1802 O_RDONLY | O_CLOEXEC);
1804 ret = PTR_ERR(file);
1805 goto out_put_unused_fd;
1809 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
1811 * fput() will trigger the release() callback, so do not go onto
1812 * the regular error cleanup path here.
1819 fd_install(fd, file);
1830 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
1831 struct gpioline_info *info_v1)
1833 u64 flagsv2 = info_v2->flags;
1835 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
1836 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
1837 info_v1->line_offset = info_v2->offset;
1840 if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
1841 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
1843 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
1844 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
1846 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
1847 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
1849 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
1850 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
1851 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
1852 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
1854 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
1855 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
1856 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
1857 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
1858 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
1859 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
1862 static void gpio_v2_line_info_changed_to_v1(
1863 struct gpio_v2_line_info_changed *lic_v2,
1864 struct gpioline_info_changed *lic_v1)
1866 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
1867 lic_v1->timestamp = lic_v2->timestamp_ns;
1868 lic_v1->event_type = lic_v2->event_type;
1871 #endif /* CONFIG_GPIO_CDEV_V1 */
1873 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
1874 struct gpio_v2_line_info *info)
1876 struct gpio_chip *gc = desc->gdev->chip;
1877 bool ok_for_pinctrl;
1878 unsigned long flags;
1879 u32 debounce_period_us;
1880 unsigned int num_attrs = 0;
1882 memset(info, 0, sizeof(*info));
1883 info->offset = gpio_chip_hwgpio(desc);
1886 * This function takes a mutex so we must check this before taking
1889 * FIXME: find a non-racy way to retrieve this information. Maybe a
1890 * lock common to both frameworks?
1893 pinctrl_gpio_can_use_line(gc->base + info->offset);
1895 spin_lock_irqsave(&gpio_lock, flags);
1898 strscpy(info->name, desc->name, sizeof(info->name));
1901 strscpy(info->consumer, desc->label, sizeof(info->consumer));
1904 * Userspace only need to know that the kernel is using this GPIO so
1908 if (test_bit(FLAG_REQUESTED, &desc->flags) ||
1909 test_bit(FLAG_IS_HOGGED, &desc->flags) ||
1910 test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
1911 test_bit(FLAG_EXPORT, &desc->flags) ||
1912 test_bit(FLAG_SYSFS, &desc->flags) ||
1914 info->flags |= GPIO_V2_LINE_FLAG_USED;
1916 if (test_bit(FLAG_IS_OUT, &desc->flags))
1917 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
1919 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
1921 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1922 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
1924 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1925 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
1926 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1927 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
1929 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
1930 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
1931 if (test_bit(FLAG_PULL_DOWN, &desc->flags))
1932 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
1933 if (test_bit(FLAG_PULL_UP, &desc->flags))
1934 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
1936 if (test_bit(FLAG_EDGE_RISING, &desc->flags))
1937 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
1938 if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
1939 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
1941 debounce_period_us = READ_ONCE(desc->debounce_period_us);
1942 if (debounce_period_us) {
1943 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
1944 info->attrs[num_attrs].debounce_period_us = debounce_period_us;
1947 info->num_attrs = num_attrs;
1949 spin_unlock_irqrestore(&gpio_lock, flags);
1952 struct gpio_chardev_data {
1953 struct gpio_device *gdev;
1954 wait_queue_head_t wait;
1955 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
1956 struct notifier_block lineinfo_changed_nb;
1957 unsigned long *watched_lines;
1958 #ifdef CONFIG_GPIO_CDEV_V1
1959 atomic_t watch_abi_version;
1963 #ifdef CONFIG_GPIO_CDEV_V1
1965 * returns 0 if the versions match, else the previously selected ABI version
1967 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
1968 unsigned int version)
1970 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
1972 if (abiv == version)
1979 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
1982 struct gpio_desc *desc;
1983 struct gpio_v2_line_info lineinfo;
1985 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
1988 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
1991 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
1993 return PTR_ERR(desc);
1996 #ifdef CONFIG_GPIO_CDEV_V1
1997 if (lineinfo_ensure_abi_version(cdev, 2))
2000 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2003 gpio_desc_to_lineinfo(desc, &lineinfo);
2005 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2007 clear_bit(lineinfo.offset, cdev->watched_lines);
2015 * gpio_ioctl() - ioctl handler for the GPIO chardev
2017 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2019 struct gpio_chardev_data *cdev = file->private_data;
2020 struct gpio_device *gdev = cdev->gdev;
2021 struct gpio_chip *gc = gdev->chip;
2022 void __user *ip = (void __user *)arg;
2025 /* We fail any subsequent ioctl():s when the chip is gone */
2029 /* Fill in the struct and pass to userspace */
2030 if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
2031 struct gpiochip_info chipinfo;
2033 memset(&chipinfo, 0, sizeof(chipinfo));
2035 strscpy(chipinfo.name, dev_name(&gdev->dev),
2036 sizeof(chipinfo.name));
2037 strscpy(chipinfo.label, gdev->label,
2038 sizeof(chipinfo.label));
2039 chipinfo.lines = gdev->ngpio;
2040 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
2043 #ifdef CONFIG_GPIO_CDEV_V1
2044 } else if (cmd == GPIO_GET_LINEINFO_IOCTL) {
2045 struct gpio_desc *desc;
2046 struct gpioline_info lineinfo;
2047 struct gpio_v2_line_info lineinfo_v2;
2049 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2052 /* this doubles as a range check on line_offset */
2053 desc = gpiochip_get_desc(gc, lineinfo.line_offset);
2055 return PTR_ERR(desc);
2057 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2058 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2060 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
2063 } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
2064 return linehandle_create(gdev, ip);
2065 } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
2066 return lineevent_create(gdev, ip);
2067 } else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
2068 struct gpio_desc *desc;
2069 struct gpioline_info lineinfo;
2070 struct gpio_v2_line_info lineinfo_v2;
2072 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2075 /* this doubles as a range check on line_offset */
2076 desc = gpiochip_get_desc(gc, lineinfo.line_offset);
2078 return PTR_ERR(desc);
2080 if (lineinfo_ensure_abi_version(cdev, 1))
2083 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2086 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2087 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2089 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2090 clear_bit(lineinfo.line_offset, cdev->watched_lines);
2095 #endif /* CONFIG_GPIO_CDEV_V1 */
2096 } else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL ||
2097 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) {
2098 return lineinfo_get(cdev, ip,
2099 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL);
2100 } else if (cmd == GPIO_V2_GET_LINE_IOCTL) {
2101 return linereq_create(gdev, ip);
2102 } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
2103 if (copy_from_user(&offset, ip, sizeof(offset)))
2106 if (offset >= cdev->gdev->ngpio)
2109 if (!test_and_clear_bit(offset, cdev->watched_lines))
2117 #ifdef CONFIG_COMPAT
2118 static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2121 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2125 static struct gpio_chardev_data *
2126 to_gpio_chardev_data(struct notifier_block *nb)
2128 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2131 static int lineinfo_changed_notify(struct notifier_block *nb,
2132 unsigned long action, void *data)
2134 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb);
2135 struct gpio_v2_line_info_changed chg;
2136 struct gpio_desc *desc = data;
2139 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
2142 memset(&chg, 0, sizeof(chg));
2143 chg.event_type = action;
2144 chg.timestamp_ns = ktime_get_ns();
2145 gpio_desc_to_lineinfo(desc, &chg.info);
2147 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
2149 wake_up_poll(&cdev->wait, EPOLLIN);
2151 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2156 static __poll_t lineinfo_watch_poll(struct file *file,
2157 struct poll_table_struct *pollt)
2159 struct gpio_chardev_data *cdev = file->private_data;
2160 __poll_t events = 0;
2162 poll_wait(file, &cdev->wait, pollt);
2164 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2166 events = EPOLLIN | EPOLLRDNORM;
2171 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2172 size_t count, loff_t *off)
2174 struct gpio_chardev_data *cdev = file->private_data;
2175 struct gpio_v2_line_info_changed event;
2176 ssize_t bytes_read = 0;
2180 #ifndef CONFIG_GPIO_CDEV_V1
2181 event_size = sizeof(struct gpio_v2_line_info_changed);
2182 if (count < event_size)
2187 spin_lock(&cdev->wait.lock);
2188 if (kfifo_is_empty(&cdev->events)) {
2190 spin_unlock(&cdev->wait.lock);
2194 if (file->f_flags & O_NONBLOCK) {
2195 spin_unlock(&cdev->wait.lock);
2199 ret = wait_event_interruptible_locked(cdev->wait,
2200 !kfifo_is_empty(&cdev->events));
2202 spin_unlock(&cdev->wait.lock);
2206 #ifdef CONFIG_GPIO_CDEV_V1
2207 /* must be after kfifo check so watch_abi_version is set */
2208 if (atomic_read(&cdev->watch_abi_version) == 2)
2209 event_size = sizeof(struct gpio_v2_line_info_changed);
2211 event_size = sizeof(struct gpioline_info_changed);
2212 if (count < event_size) {
2213 spin_unlock(&cdev->wait.lock);
2217 ret = kfifo_out(&cdev->events, &event, 1);
2218 spin_unlock(&cdev->wait.lock);
2222 /* We should never get here. See lineevent_read(). */
2225 #ifdef CONFIG_GPIO_CDEV_V1
2226 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2227 if (copy_to_user(buf + bytes_read, &event, event_size))
2230 struct gpioline_info_changed event_v1;
2232 gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2233 if (copy_to_user(buf + bytes_read, &event_v1,
2238 if (copy_to_user(buf + bytes_read, &event, event_size))
2241 bytes_read += event_size;
2242 } while (count >= bytes_read + sizeof(event));
2248 * gpio_chrdev_open() - open the chardev for ioctl operations
2249 * @inode: inode for this chardev
2250 * @file: file struct for storing private data
2251 * Returns 0 on success
2253 static int gpio_chrdev_open(struct inode *inode, struct file *file)
2255 struct gpio_device *gdev = container_of(inode->i_cdev,
2256 struct gpio_device, chrdev);
2257 struct gpio_chardev_data *cdev;
2260 /* Fail on open if the backing gpiochip is gone */
2264 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2268 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
2269 if (!cdev->watched_lines)
2272 init_waitqueue_head(&cdev->wait);
2273 INIT_KFIFO(cdev->events);
2276 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2277 ret = blocking_notifier_chain_register(&gdev->notifier,
2278 &cdev->lineinfo_changed_nb);
2280 goto out_free_bitmap;
2282 get_device(&gdev->dev);
2283 file->private_data = cdev;
2285 ret = nonseekable_open(inode, file);
2287 goto out_unregister_notifier;
2291 out_unregister_notifier:
2292 blocking_notifier_chain_unregister(&gdev->notifier,
2293 &cdev->lineinfo_changed_nb);
2295 bitmap_free(cdev->watched_lines);
2302 * gpio_chrdev_release() - close chardev after ioctl operations
2303 * @inode: inode for this chardev
2304 * @file: file struct for storing private data
2305 * Returns 0 on success
2307 static int gpio_chrdev_release(struct inode *inode, struct file *file)
2309 struct gpio_chardev_data *cdev = file->private_data;
2310 struct gpio_device *gdev = cdev->gdev;
2312 bitmap_free(cdev->watched_lines);
2313 blocking_notifier_chain_unregister(&gdev->notifier,
2314 &cdev->lineinfo_changed_nb);
2315 put_device(&gdev->dev);
2321 static const struct file_operations gpio_fileops = {
2322 .release = gpio_chrdev_release,
2323 .open = gpio_chrdev_open,
2324 .poll = lineinfo_watch_poll,
2325 .read = lineinfo_watch_read,
2326 .owner = THIS_MODULE,
2327 .llseek = no_llseek,
2328 .unlocked_ioctl = gpio_ioctl,
2329 #ifdef CONFIG_COMPAT
2330 .compat_ioctl = gpio_ioctl_compat,
2334 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
2338 cdev_init(&gdev->chrdev, &gpio_fileops);
2339 gdev->chrdev.owner = THIS_MODULE;
2340 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2342 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2346 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
2347 MAJOR(devt), gdev->id);
2352 void gpiolib_cdev_unregister(struct gpio_device *gdev)
2354 cdev_device_del(&gdev->chrdev, &gdev->dev);