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/cleanup.h>
9 #include <linux/compat.h>
10 #include <linux/compiler.h>
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/file.h>
14 #include <linux/gpio.h>
15 #include <linux/gpio/driver.h>
16 #include <linux/hte.h>
17 #include <linux/interrupt.h>
18 #include <linux/irqreturn.h>
19 #include <linux/kernel.h>
20 #include <linux/kfifo.h>
21 #include <linux/module.h>
22 #include <linux/mutex.h>
23 #include <linux/overflow.h>
24 #include <linux/pinctrl/consumer.h>
25 #include <linux/poll.h>
26 #include <linux/rbtree.h>
27 #include <linux/seq_file.h>
28 #include <linux/spinlock.h>
29 #include <linux/timekeeping.h>
30 #include <linux/uaccess.h>
31 #include <linux/workqueue.h>
33 #include <uapi/linux/gpio.h>
36 #include "gpiolib-cdev.h"
39 * Array sizes must ensure 64-bit alignment and not create holes in the
42 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
43 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
46 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
50 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
51 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
52 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
53 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
54 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
55 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
57 /* Character device interface to GPIO.
59 * The GPIO character device, /dev/gpiochipN, provides userspace an
60 * interface to gpiolib GPIOs via ioctl()s.
64 * GPIO line handle management
67 #ifdef CONFIG_GPIO_CDEV_V1
69 * struct linehandle_state - contains the state of a userspace handle
70 * @gdev: the GPIO device the handle pertains to
71 * @label: consumer label used to tag descriptors
72 * @descs: the GPIO descriptors held by this handle
73 * @num_descs: the number of descriptors held in the descs array
75 struct linehandle_state {
76 struct gpio_device *gdev;
78 struct gpio_desc *descs[GPIOHANDLES_MAX];
82 #define GPIOHANDLE_REQUEST_VALID_FLAGS \
83 (GPIOHANDLE_REQUEST_INPUT | \
84 GPIOHANDLE_REQUEST_OUTPUT | \
85 GPIOHANDLE_REQUEST_ACTIVE_LOW | \
86 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
87 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
88 GPIOHANDLE_REQUEST_BIAS_DISABLE | \
89 GPIOHANDLE_REQUEST_OPEN_DRAIN | \
90 GPIOHANDLE_REQUEST_OPEN_SOURCE)
92 static int linehandle_validate_flags(u32 flags)
94 /* Return an error if an unknown flag is set */
95 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
99 * Do not allow both INPUT & OUTPUT flags to be set as they are
102 if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
103 (flags & GPIOHANDLE_REQUEST_OUTPUT))
107 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
108 * the hardware actually supports enabling both at the same time the
109 * electrical result would be disastrous.
111 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
112 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
115 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
116 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
117 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
118 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
121 /* Bias flags only allowed for input or output mode. */
122 if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
123 (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
124 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
125 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
126 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
129 /* Only one bias flag can be set. */
130 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
131 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
132 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
133 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
134 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
140 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
142 assign_bit(FLAG_ACTIVE_LOW, flagsp,
143 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
144 assign_bit(FLAG_OPEN_DRAIN, flagsp,
145 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
146 assign_bit(FLAG_OPEN_SOURCE, flagsp,
147 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
148 assign_bit(FLAG_PULL_UP, flagsp,
149 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
150 assign_bit(FLAG_PULL_DOWN, flagsp,
151 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
152 assign_bit(FLAG_BIAS_DISABLE, flagsp,
153 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
156 static long linehandle_set_config(struct linehandle_state *lh,
159 struct gpiohandle_config gcnf;
160 struct gpio_desc *desc;
164 if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
168 ret = linehandle_validate_flags(lflags);
172 for (i = 0; i < lh->num_descs; i++) {
174 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
177 * Lines have to be requested explicitly for input
178 * or output, else the line will be treated "as is".
180 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
181 int val = !!gcnf.default_values[i];
183 ret = gpiod_direction_output(desc, val);
186 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
187 ret = gpiod_direction_input(desc);
192 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
197 static long linehandle_ioctl(struct file *file, unsigned int cmd,
200 struct linehandle_state *lh = file->private_data;
201 void __user *ip = (void __user *)arg;
202 struct gpiohandle_data ghd;
203 DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
207 guard(srcu)(&lh->gdev->srcu);
209 if (!rcu_access_pointer(lh->gdev->chip))
213 case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
214 /* NOTE: It's okay to read values of output lines */
215 ret = gpiod_get_array_value_complex(false, true,
216 lh->num_descs, lh->descs,
221 memset(&ghd, 0, sizeof(ghd));
222 for (i = 0; i < lh->num_descs; i++)
223 ghd.values[i] = test_bit(i, vals);
225 if (copy_to_user(ip, &ghd, sizeof(ghd)))
229 case GPIOHANDLE_SET_LINE_VALUES_IOCTL:
231 * All line descriptors were created at once with the same
232 * flags so just check if the first one is really output.
234 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
237 if (copy_from_user(&ghd, ip, sizeof(ghd)))
240 /* Clamp all values to [0,1] */
241 for (i = 0; i < lh->num_descs; i++)
242 __assign_bit(i, vals, ghd.values[i]);
244 /* Reuse the array setting function */
245 return gpiod_set_array_value_complex(false,
251 case GPIOHANDLE_SET_CONFIG_IOCTL:
252 return linehandle_set_config(lh, ip);
259 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
262 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
266 static void linehandle_free(struct linehandle_state *lh)
270 for (i = 0; i < lh->num_descs; i++)
272 gpiod_free(lh->descs[i]);
274 gpio_device_put(lh->gdev);
278 static int linehandle_release(struct inode *inode, struct file *file)
280 linehandle_free(file->private_data);
284 static const struct file_operations linehandle_fileops = {
285 .release = linehandle_release,
286 .owner = THIS_MODULE,
287 .llseek = noop_llseek,
288 .unlocked_ioctl = linehandle_ioctl,
290 .compat_ioctl = linehandle_ioctl_compat,
294 static int linehandle_create(struct gpio_device *gdev, void __user *ip)
296 struct gpiohandle_request handlereq;
297 struct linehandle_state *lh;
302 if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
304 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
307 lflags = handlereq.flags;
309 ret = linehandle_validate_flags(lflags);
313 lh = kzalloc(sizeof(*lh), GFP_KERNEL);
316 lh->gdev = gpio_device_get(gdev);
318 if (handlereq.consumer_label[0] != '\0') {
319 /* label is only initialized if consumer_label is set */
320 lh->label = kstrndup(handlereq.consumer_label,
321 sizeof(handlereq.consumer_label) - 1,
329 lh->num_descs = handlereq.lines;
331 /* Request each GPIO */
332 for (i = 0; i < handlereq.lines; i++) {
333 u32 offset = handlereq.lineoffsets[i];
334 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
341 ret = gpiod_request_user(desc, lh->label);
345 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
347 ret = gpiod_set_transitory(desc, false);
352 * Lines have to be requested explicitly for input
353 * or output, else the line will be treated "as is".
355 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
356 int val = !!handlereq.default_values[i];
358 ret = gpiod_direction_output(desc, val);
361 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
362 ret = gpiod_direction_input(desc);
367 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
369 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
373 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
379 file = anon_inode_getfile("gpio-linehandle",
382 O_RDONLY | O_CLOEXEC);
385 goto out_put_unused_fd;
389 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
391 * fput() will trigger the release() callback, so do not go onto
392 * the regular error cleanup path here.
399 fd_install(fd, file);
401 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
412 #endif /* CONFIG_GPIO_CDEV_V1 */
415 * struct line - contains the state of a requested line
416 * @node: to store the object in supinfo_tree if supplemental
417 * @desc: the GPIO descriptor for this line.
418 * @req: the corresponding line request
419 * @irq: the interrupt triggered in response to events on this GPIO
420 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
421 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
422 * @timestamp_ns: cache for the timestamp storing it between hardirq and
423 * IRQ thread, used to bring the timestamp close to the actual event
424 * @req_seqno: the seqno for the current edge event in the sequence of
425 * events for the corresponding line request. This is drawn from the @req.
426 * @line_seqno: the seqno for the current edge event in the sequence of
427 * events for this line.
428 * @work: the worker that implements software debouncing
429 * @debounce_period_us: the debounce period in microseconds
430 * @sw_debounced: flag indicating if the software debouncer is active
431 * @level: the current debounced physical level of the line
432 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
433 * @raw_level: the line level at the time of event
434 * @total_discard_seq: the running counter of the discarded events
435 * @last_seqno: the last sequence number before debounce period expires
439 struct gpio_desc *desc;
441 * -- edge detector specific fields --
446 * The flags for the active edge detector configuration.
448 * edflags is set by linereq_create(), linereq_free(), and
449 * linereq_set_config_unlocked(), which are themselves mutually
450 * exclusive, and is accessed by edge_irq_thread(),
451 * process_hw_ts_thread() and debounce_work_func(),
452 * which can all live with a slightly stale value.
456 * timestamp_ns and req_seqno are accessed only by
457 * edge_irq_handler() and edge_irq_thread(), which are themselves
458 * mutually exclusive, so no additional protection is necessary.
463 * line_seqno is accessed by either edge_irq_thread() or
464 * debounce_work_func(), which are themselves mutually exclusive,
465 * so no additional protection is necessary.
469 * -- debouncer specific fields --
471 struct delayed_work work;
473 * debounce_period_us is accessed by debounce_irq_handler() and
474 * process_hw_ts() which are disabled when modified by
475 * debounce_setup(), edge_detector_setup() or edge_detector_stop()
476 * or can live with a stale version when updated by
477 * edge_detector_update().
478 * The modifying functions are themselves mutually exclusive.
480 unsigned int debounce_period_us;
482 * sw_debounce is accessed by linereq_set_config(), which is the
483 * only setter, and linereq_get_values(), which can live with a
484 * slightly stale value.
486 unsigned int sw_debounced;
488 * level is accessed by debounce_work_func(), which is the only
489 * setter, and linereq_get_values() which can live with a slightly
494 struct hte_ts_desc hdesc;
496 * HTE provider sets line level at the time of event. The valid
497 * value is 0 or 1 and negative value for an error.
501 * when sw_debounce is set on HTE enabled line, this is running
502 * counter of the discarded events.
504 u32 total_discard_seq;
506 * when sw_debounce is set on HTE enabled line, this variable records
507 * last sequence number before debounce period expires.
510 #endif /* CONFIG_HTE */
514 * a rbtree of the struct lines containing supplemental info.
515 * Used to populate gpio_v2_line_info with cdev specific fields not contained
516 * in the struct gpio_desc.
517 * A line is determined to contain supplemental information by
518 * line_has_supinfo().
520 static struct rb_root supinfo_tree = RB_ROOT;
521 /* covers supinfo_tree */
522 static DEFINE_SPINLOCK(supinfo_lock);
525 * struct linereq - contains the state of a userspace line request
526 * @gdev: the GPIO device the line request pertains to
527 * @label: consumer label used to tag GPIO descriptors
528 * @num_lines: the number of lines in the lines array
529 * @wait: wait queue that handles blocking reads of events
530 * @device_unregistered_nb: notifier block for receiving gdev unregister events
531 * @event_buffer_size: the number of elements allocated in @events
532 * @events: KFIFO for the GPIO events
533 * @seqno: the sequence number for edge events generated on all lines in
534 * this line request. Note that this is not used when @num_lines is 1, as
535 * the line_seqno is then the same and is cheaper to calculate.
536 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
537 * of configuration, particularly multi-step accesses to desc flags and
538 * changes to supinfo status.
539 * @lines: the lines held by this line request, with @num_lines elements.
542 struct gpio_device *gdev;
545 wait_queue_head_t wait;
546 struct notifier_block device_unregistered_nb;
547 u32 event_buffer_size;
548 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
550 struct mutex config_mutex;
551 struct line lines[] __counted_by(num_lines);
554 static void supinfo_insert(struct line *line)
556 struct rb_node **new = &(supinfo_tree.rb_node), *parent = NULL;
559 guard(spinlock)(&supinfo_lock);
562 entry = container_of(*new, struct line, node);
565 if (line->desc < entry->desc) {
566 new = &((*new)->rb_left);
567 } else if (line->desc > entry->desc) {
568 new = &((*new)->rb_right);
570 /* this should never happen */
571 WARN(1, "duplicate line inserted");
576 rb_link_node(&line->node, parent, new);
577 rb_insert_color(&line->node, &supinfo_tree);
580 static void supinfo_erase(struct line *line)
582 guard(spinlock)(&supinfo_lock);
584 rb_erase(&line->node, &supinfo_tree);
587 static struct line *supinfo_find(struct gpio_desc *desc)
589 struct rb_node *node = supinfo_tree.rb_node;
593 line = container_of(node, struct line, node);
594 if (desc < line->desc)
595 node = node->rb_left;
596 else if (desc > line->desc)
597 node = node->rb_right;
604 static void supinfo_to_lineinfo(struct gpio_desc *desc,
605 struct gpio_v2_line_info *info)
607 struct gpio_v2_line_attribute *attr;
610 guard(spinlock)(&supinfo_lock);
612 line = supinfo_find(desc);
616 attr = &info->attrs[info->num_attrs];
617 attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
618 attr->debounce_period_us = READ_ONCE(line->debounce_period_us);
622 static inline bool line_has_supinfo(struct line *line)
624 return READ_ONCE(line->debounce_period_us);
628 * Checks line_has_supinfo() before and after the change to avoid unnecessary
629 * supinfo_tree access.
630 * Called indirectly by linereq_create() or linereq_set_config() so line
631 * is already protected from concurrent changes.
633 static void line_set_debounce_period(struct line *line,
634 unsigned int debounce_period_us)
636 bool was_suppl = line_has_supinfo(line);
638 WRITE_ONCE(line->debounce_period_us, debounce_period_us);
640 /* if supinfo status is unchanged then we're done */
641 if (line_has_supinfo(line) == was_suppl)
644 /* supinfo status has changed, so update the tree */
648 supinfo_insert(line);
651 #define GPIO_V2_LINE_BIAS_FLAGS \
652 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
653 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
654 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
656 #define GPIO_V2_LINE_DIRECTION_FLAGS \
657 (GPIO_V2_LINE_FLAG_INPUT | \
658 GPIO_V2_LINE_FLAG_OUTPUT)
660 #define GPIO_V2_LINE_DRIVE_FLAGS \
661 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
662 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
664 #define GPIO_V2_LINE_EDGE_FLAGS \
665 (GPIO_V2_LINE_FLAG_EDGE_RISING | \
666 GPIO_V2_LINE_FLAG_EDGE_FALLING)
668 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
670 #define GPIO_V2_LINE_VALID_FLAGS \
671 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
672 GPIO_V2_LINE_DIRECTION_FLAGS | \
673 GPIO_V2_LINE_DRIVE_FLAGS | \
674 GPIO_V2_LINE_EDGE_FLAGS | \
675 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
676 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
677 GPIO_V2_LINE_BIAS_FLAGS)
679 /* subset of flags relevant for edge detector configuration */
680 #define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
681 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
682 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
683 GPIO_V2_LINE_EDGE_FLAGS)
685 static int linereq_unregistered_notify(struct notifier_block *nb,
686 unsigned long action, void *data)
688 struct linereq *lr = container_of(nb, struct linereq,
689 device_unregistered_nb);
691 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR);
696 static void linereq_put_event(struct linereq *lr,
697 struct gpio_v2_line_event *le)
699 bool overflow = false;
701 scoped_guard(spinlock, &lr->wait.lock) {
702 if (kfifo_is_full(&lr->events)) {
704 kfifo_skip(&lr->events);
706 kfifo_in(&lr->events, le, 1);
709 wake_up_poll(&lr->wait, EPOLLIN);
711 pr_debug_ratelimited("event FIFO is full - event dropped\n");
714 static u64 line_event_timestamp(struct line *line)
716 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
717 return ktime_get_real_ns();
718 else if (IS_ENABLED(CONFIG_HTE) &&
719 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
720 return line->timestamp_ns;
722 return ktime_get_ns();
725 static u32 line_event_id(int level)
727 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
728 GPIO_V2_LINE_EVENT_FALLING_EDGE;
733 static enum hte_return process_hw_ts_thread(void *p)
737 struct gpio_v2_line_event le;
742 return HTE_CB_HANDLED;
747 memset(&le, 0, sizeof(le));
749 le.timestamp_ns = line->timestamp_ns;
750 edflags = READ_ONCE(line->edflags);
752 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
753 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
754 level = (line->raw_level >= 0) ?
756 gpiod_get_raw_value_cansleep(line->desc);
758 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
761 le.id = line_event_id(level);
763 case GPIO_V2_LINE_FLAG_EDGE_RISING:
764 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
766 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
767 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
770 return HTE_CB_HANDLED;
772 le.line_seqno = line->line_seqno;
773 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
774 le.offset = gpio_chip_hwgpio(line->desc);
776 linereq_put_event(lr, &le);
778 return HTE_CB_HANDLED;
781 static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
788 return HTE_CB_HANDLED;
791 line->timestamp_ns = ts->tsc;
792 line->raw_level = ts->raw_level;
795 if (READ_ONCE(line->sw_debounced)) {
796 line->total_discard_seq++;
797 line->last_seqno = ts->seq;
798 mod_delayed_work(system_wq, &line->work,
799 usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
801 if (unlikely(ts->seq < line->line_seqno))
802 return HTE_CB_HANDLED;
804 diff_seqno = ts->seq - line->line_seqno;
805 line->line_seqno = ts->seq;
806 if (lr->num_lines != 1)
807 line->req_seqno = atomic_add_return(diff_seqno,
810 return HTE_RUN_SECOND_CB;
813 return HTE_CB_HANDLED;
816 static int hte_edge_setup(struct line *line, u64 eflags)
819 unsigned long flags = 0;
820 struct hte_ts_desc *hdesc = &line->hdesc;
822 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
823 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
824 HTE_FALLING_EDGE_TS :
826 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
827 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
831 line->total_discard_seq = 0;
833 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
836 ret = hte_ts_get(NULL, hdesc, 0);
840 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
846 static int hte_edge_setup(struct line *line, u64 eflags)
850 #endif /* CONFIG_HTE */
852 static irqreturn_t edge_irq_thread(int irq, void *p)
854 struct line *line = p;
855 struct linereq *lr = line->req;
856 struct gpio_v2_line_event le;
858 /* Do not leak kernel stack to userspace */
859 memset(&le, 0, sizeof(le));
861 if (line->timestamp_ns) {
862 le.timestamp_ns = line->timestamp_ns;
865 * We may be running from a nested threaded interrupt in
866 * which case we didn't get the timestamp from
867 * edge_irq_handler().
869 le.timestamp_ns = line_event_timestamp(line);
870 if (lr->num_lines != 1)
871 line->req_seqno = atomic_inc_return(&lr->seqno);
873 line->timestamp_ns = 0;
875 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
876 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
877 le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
879 case GPIO_V2_LINE_FLAG_EDGE_RISING:
880 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
882 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
883 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
889 le.line_seqno = line->line_seqno;
890 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
891 le.offset = gpio_chip_hwgpio(line->desc);
893 linereq_put_event(lr, &le);
898 static irqreturn_t edge_irq_handler(int irq, void *p)
900 struct line *line = p;
901 struct linereq *lr = line->req;
904 * Just store the timestamp in hardirq context so we get it as
905 * close in time as possible to the actual event.
907 line->timestamp_ns = line_event_timestamp(line);
909 if (lr->num_lines != 1)
910 line->req_seqno = atomic_inc_return(&lr->seqno);
912 return IRQ_WAKE_THREAD;
916 * returns the current debounced logical value.
918 static bool debounced_value(struct line *line)
923 * minor race - debouncer may be stopped here, so edge_detector_stop()
924 * must leave the value unchanged so the following will read the level
925 * from when the debouncer was last running.
927 value = READ_ONCE(line->level);
929 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
935 static irqreturn_t debounce_irq_handler(int irq, void *p)
937 struct line *line = p;
939 mod_delayed_work(system_wq, &line->work,
940 usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
945 static void debounce_work_func(struct work_struct *work)
947 struct gpio_v2_line_event le;
948 struct line *line = container_of(work, struct line, work.work);
950 u64 eflags, edflags = READ_ONCE(line->edflags);
955 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
956 level = line->raw_level;
959 level = gpiod_get_raw_value_cansleep(line->desc);
961 pr_debug_ratelimited("debouncer failed to read line value\n");
965 if (READ_ONCE(line->level) == level)
968 WRITE_ONCE(line->level, level);
970 /* -- edge detection -- */
971 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
975 /* switch from physical level to logical - if they differ */
976 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
979 /* ignore edges that are not being monitored */
980 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
981 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
984 /* Do not leak kernel stack to userspace */
985 memset(&le, 0, sizeof(le));
988 le.timestamp_ns = line_event_timestamp(line);
989 le.offset = gpio_chip_hwgpio(line->desc);
991 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
992 /* discard events except the last one */
993 line->total_discard_seq -= 1;
994 diff_seqno = line->last_seqno - line->total_discard_seq -
996 line->line_seqno = line->last_seqno - line->total_discard_seq;
997 le.line_seqno = line->line_seqno;
998 le.seqno = (lr->num_lines == 1) ?
999 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
1001 #endif /* CONFIG_HTE */
1004 le.line_seqno = line->line_seqno;
1005 le.seqno = (lr->num_lines == 1) ?
1006 le.line_seqno : atomic_inc_return(&lr->seqno);
1009 le.id = line_event_id(level);
1011 linereq_put_event(lr, &le);
1014 static int debounce_setup(struct line *line, unsigned int debounce_period_us)
1016 unsigned long irqflags;
1017 int ret, level, irq;
1020 ret = gpiod_set_debounce(line->desc, debounce_period_us);
1022 line_set_debounce_period(line, debounce_period_us);
1025 if (ret != -ENOTSUPP)
1028 if (debounce_period_us) {
1029 /* setup software debounce */
1030 level = gpiod_get_raw_value_cansleep(line->desc);
1034 if (!(IS_ENABLED(CONFIG_HTE) &&
1035 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
1036 irq = gpiod_to_irq(line->desc);
1040 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
1041 ret = request_irq(irq, debounce_irq_handler, irqflags,
1042 line->req->label, line);
1047 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
1052 WRITE_ONCE(line->level, level);
1053 WRITE_ONCE(line->sw_debounced, 1);
1058 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
1059 unsigned int line_idx)
1062 u64 mask = BIT_ULL(line_idx);
1064 for (i = 0; i < lc->num_attrs; i++) {
1065 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
1066 (lc->attrs[i].mask & mask))
1072 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
1073 unsigned int line_idx)
1076 u64 mask = BIT_ULL(line_idx);
1078 for (i = 0; i < lc->num_attrs; i++) {
1079 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
1080 (lc->attrs[i].mask & mask))
1081 return lc->attrs[i].attr.debounce_period_us;
1086 static void edge_detector_stop(struct line *line)
1089 free_irq(line->irq, line);
1094 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
1095 hte_ts_put(&line->hdesc);
1098 cancel_delayed_work_sync(&line->work);
1099 WRITE_ONCE(line->sw_debounced, 0);
1100 WRITE_ONCE(line->edflags, 0);
1101 line_set_debounce_period(line, 0);
1102 /* do not change line->level - see comment in debounced_value() */
1105 static int edge_detector_setup(struct line *line,
1106 struct gpio_v2_line_config *lc,
1107 unsigned int line_idx, u64 edflags)
1109 u32 debounce_period_us;
1110 unsigned long irqflags = 0;
1114 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
1115 if (eflags && !kfifo_initialized(&line->req->events)) {
1116 ret = kfifo_alloc(&line->req->events,
1117 line->req->event_buffer_size, GFP_KERNEL);
1121 if (gpio_v2_line_config_debounced(lc, line_idx)) {
1122 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
1123 ret = debounce_setup(line, debounce_period_us);
1126 line_set_debounce_period(line, debounce_period_us);
1129 /* detection disabled or sw debouncer will provide edge detection */
1130 if (!eflags || READ_ONCE(line->sw_debounced))
1133 if (IS_ENABLED(CONFIG_HTE) &&
1134 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1135 return hte_edge_setup(line, edflags);
1137 irq = gpiod_to_irq(line->desc);
1141 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
1142 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1143 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1144 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
1145 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1146 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1147 irqflags |= IRQF_ONESHOT;
1149 /* Request a thread to read the events */
1150 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
1151 irqflags, line->req->label, line);
1159 static int edge_detector_update(struct line *line,
1160 struct gpio_v2_line_config *lc,
1161 unsigned int line_idx, u64 edflags)
1163 u64 active_edflags = READ_ONCE(line->edflags);
1164 unsigned int debounce_period_us =
1165 gpio_v2_line_config_debounce_period(lc, line_idx);
1167 if ((active_edflags == edflags) &&
1168 (READ_ONCE(line->debounce_period_us) == debounce_period_us))
1171 /* sw debounced and still will be...*/
1172 if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
1173 line_set_debounce_period(line, debounce_period_us);
1177 /* reconfiguring edge detection or sw debounce being disabled */
1178 if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
1179 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
1180 (!debounce_period_us && READ_ONCE(line->sw_debounced)))
1181 edge_detector_stop(line);
1183 return edge_detector_setup(line, lc, line_idx, edflags);
1186 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
1187 unsigned int line_idx)
1190 u64 mask = BIT_ULL(line_idx);
1192 for (i = 0; i < lc->num_attrs; i++) {
1193 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
1194 (lc->attrs[i].mask & mask))
1195 return lc->attrs[i].attr.flags;
1200 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
1201 unsigned int line_idx)
1204 u64 mask = BIT_ULL(line_idx);
1206 for (i = 0; i < lc->num_attrs; i++) {
1207 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
1208 (lc->attrs[i].mask & mask))
1209 return !!(lc->attrs[i].attr.values & mask);
1214 static int gpio_v2_line_flags_validate(u64 flags)
1216 /* Return an error if an unknown flag is set */
1217 if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
1220 if (!IS_ENABLED(CONFIG_HTE) &&
1221 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1225 * Do not allow both INPUT and OUTPUT flags to be set as they are
1228 if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
1229 (flags & GPIO_V2_LINE_FLAG_OUTPUT))
1232 /* Only allow one event clock source */
1233 if (IS_ENABLED(CONFIG_HTE) &&
1234 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
1235 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1238 /* Edge detection requires explicit input. */
1239 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
1240 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1244 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
1245 * request. If the hardware actually supports enabling both at the
1246 * same time the electrical result would be disastrous.
1248 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
1249 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
1252 /* Drive requires explicit output direction. */
1253 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
1254 !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
1257 /* Bias requires explicit direction. */
1258 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
1259 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
1262 /* Only one bias flag can be set. */
1263 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
1264 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
1265 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
1266 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
1267 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
1273 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
1274 unsigned int num_lines)
1280 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
1283 if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
1286 for (i = 0; i < num_lines; i++) {
1287 flags = gpio_v2_line_config_flags(lc, i);
1288 ret = gpio_v2_line_flags_validate(flags);
1292 /* debounce requires explicit input */
1293 if (gpio_v2_line_config_debounced(lc, i) &&
1294 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1300 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
1301 unsigned long *flagsp)
1303 assign_bit(FLAG_ACTIVE_LOW, flagsp,
1304 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
1306 if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
1307 set_bit(FLAG_IS_OUT, flagsp);
1308 else if (flags & GPIO_V2_LINE_FLAG_INPUT)
1309 clear_bit(FLAG_IS_OUT, flagsp);
1311 assign_bit(FLAG_EDGE_RISING, flagsp,
1312 flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
1313 assign_bit(FLAG_EDGE_FALLING, flagsp,
1314 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
1316 assign_bit(FLAG_OPEN_DRAIN, flagsp,
1317 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
1318 assign_bit(FLAG_OPEN_SOURCE, flagsp,
1319 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
1321 assign_bit(FLAG_PULL_UP, flagsp,
1322 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
1323 assign_bit(FLAG_PULL_DOWN, flagsp,
1324 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
1325 assign_bit(FLAG_BIAS_DISABLE, flagsp,
1326 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
1328 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp,
1329 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
1330 assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp,
1331 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
1334 static long linereq_get_values(struct linereq *lr, void __user *ip)
1336 struct gpio_v2_line_values lv;
1337 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1338 struct gpio_desc **descs;
1339 unsigned int i, didx, num_get;
1343 /* NOTE: It's ok to read values of output lines. */
1344 if (copy_from_user(&lv, ip, sizeof(lv)))
1348 * gpiod_get_array_value_complex() requires compacted desc and val
1349 * arrays, rather than the sparse ones in lv.
1350 * Calculation of num_get and construction of the desc array is
1351 * optimized to avoid allocation for the desc array for the common
1352 * num_get == 1 case.
1354 /* scan requested lines to calculate the subset to get */
1355 for (num_get = 0, i = 0; i < lr->num_lines; i++) {
1356 if (lv.mask & BIT_ULL(i)) {
1358 /* capture desc for the num_get == 1 case */
1359 descs = &lr->lines[i].desc;
1367 /* build compacted desc array */
1368 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
1371 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1372 if (lv.mask & BIT_ULL(i)) {
1373 descs[didx] = lr->lines[i].desc;
1378 ret = gpiod_get_array_value_complex(false, true, num_get,
1387 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1388 /* unpack compacted vals for the response */
1389 if (lv.mask & BIT_ULL(i)) {
1390 if (lr->lines[i].sw_debounced)
1391 val = debounced_value(&lr->lines[i]);
1393 val = test_bit(didx, vals);
1395 lv.bits |= BIT_ULL(i);
1400 if (copy_to_user(ip, &lv, sizeof(lv)))
1406 static long linereq_set_values(struct linereq *lr, void __user *ip)
1408 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1409 struct gpio_v2_line_values lv;
1410 struct gpio_desc **descs;
1411 unsigned int i, didx, num_set;
1414 if (copy_from_user(&lv, ip, sizeof(lv)))
1417 guard(mutex)(&lr->config_mutex);
1420 * gpiod_set_array_value_complex() requires compacted desc and val
1421 * arrays, rather than the sparse ones in lv.
1422 * Calculation of num_set and construction of the descs and vals arrays
1423 * is optimized to minimize scanning the lv->mask, and to avoid
1424 * allocation for the desc array for the common num_set == 1 case.
1426 bitmap_zero(vals, GPIO_V2_LINES_MAX);
1427 /* scan requested lines to determine the subset to be set */
1428 for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1429 if (lv.mask & BIT_ULL(i)) {
1430 /* setting inputs is not allowed */
1431 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
1433 /* add to compacted values */
1434 if (lv.bits & BIT_ULL(i))
1435 __set_bit(num_set, vals);
1437 /* capture desc for the num_set == 1 case */
1438 descs = &lr->lines[i].desc;
1445 /* build compacted desc array */
1446 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
1449 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1450 if (lv.mask & BIT_ULL(i)) {
1451 descs[didx] = lr->lines[i].desc;
1456 ret = gpiod_set_array_value_complex(false, true, num_set,
1464 static long linereq_set_config(struct linereq *lr, void __user *ip)
1466 struct gpio_v2_line_config lc;
1467 struct gpio_desc *desc;
1473 if (copy_from_user(&lc, ip, sizeof(lc)))
1476 ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1480 guard(mutex)(&lr->config_mutex);
1482 for (i = 0; i < lr->num_lines; i++) {
1483 line = &lr->lines[i];
1484 desc = lr->lines[i].desc;
1485 flags = gpio_v2_line_config_flags(&lc, i);
1486 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1487 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1489 * Lines have to be requested explicitly for input
1490 * or output, else the line will be treated "as is".
1492 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1493 int val = gpio_v2_line_config_output_value(&lc, i);
1495 edge_detector_stop(line);
1496 ret = gpiod_direction_output(desc, val);
1499 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1500 ret = gpiod_direction_input(desc);
1504 ret = edge_detector_update(line, &lc, i, edflags);
1509 WRITE_ONCE(line->edflags, edflags);
1511 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
1516 static long linereq_ioctl(struct file *file, unsigned int cmd,
1519 struct linereq *lr = file->private_data;
1520 void __user *ip = (void __user *)arg;
1522 guard(srcu)(&lr->gdev->srcu);
1524 if (!rcu_access_pointer(lr->gdev->chip))
1528 case GPIO_V2_LINE_GET_VALUES_IOCTL:
1529 return linereq_get_values(lr, ip);
1530 case GPIO_V2_LINE_SET_VALUES_IOCTL:
1531 return linereq_set_values(lr, ip);
1532 case GPIO_V2_LINE_SET_CONFIG_IOCTL:
1533 return linereq_set_config(lr, ip);
1539 #ifdef CONFIG_COMPAT
1540 static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1543 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1547 static __poll_t linereq_poll(struct file *file,
1548 struct poll_table_struct *wait)
1550 struct linereq *lr = file->private_data;
1551 __poll_t events = 0;
1553 guard(srcu)(&lr->gdev->srcu);
1555 if (!rcu_access_pointer(lr->gdev->chip))
1556 return EPOLLHUP | EPOLLERR;
1558 poll_wait(file, &lr->wait, wait);
1560 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1562 events = EPOLLIN | EPOLLRDNORM;
1567 static ssize_t linereq_read(struct file *file, char __user *buf,
1568 size_t count, loff_t *f_ps)
1570 struct linereq *lr = file->private_data;
1571 struct gpio_v2_line_event le;
1572 ssize_t bytes_read = 0;
1575 guard(srcu)(&lr->gdev->srcu);
1577 if (!rcu_access_pointer(lr->gdev->chip))
1580 if (count < sizeof(le))
1584 scoped_guard(spinlock, &lr->wait.lock) {
1585 if (kfifo_is_empty(&lr->events)) {
1589 if (file->f_flags & O_NONBLOCK)
1592 ret = wait_event_interruptible_locked(lr->wait,
1593 !kfifo_is_empty(&lr->events));
1598 ret = kfifo_out(&lr->events, &le, 1);
1602 * This should never happen - we were holding the
1603 * lock from the moment we learned the fifo is no
1604 * longer empty until now.
1610 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1612 bytes_read += sizeof(le);
1613 } while (count >= bytes_read + sizeof(le));
1618 static void linereq_free(struct linereq *lr)
1623 if (lr->device_unregistered_nb.notifier_call)
1624 blocking_notifier_chain_unregister(&lr->gdev->device_notifier,
1625 &lr->device_unregistered_nb);
1627 for (i = 0; i < lr->num_lines; i++) {
1628 line = &lr->lines[i];
1632 edge_detector_stop(line);
1633 if (line_has_supinfo(line))
1634 supinfo_erase(line);
1635 gpiod_free(line->desc);
1637 kfifo_free(&lr->events);
1639 gpio_device_put(lr->gdev);
1643 static int linereq_release(struct inode *inode, struct file *file)
1645 struct linereq *lr = file->private_data;
1651 #ifdef CONFIG_PROC_FS
1652 static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
1654 struct linereq *lr = file->private_data;
1655 struct device *dev = &lr->gdev->dev;
1658 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));
1660 for (i = 0; i < lr->num_lines; i++)
1661 seq_printf(out, "gpio-line:\t%d\n",
1662 gpio_chip_hwgpio(lr->lines[i].desc));
1666 static const struct file_operations line_fileops = {
1667 .release = linereq_release,
1668 .read = linereq_read,
1669 .poll = linereq_poll,
1670 .owner = THIS_MODULE,
1671 .llseek = noop_llseek,
1672 .unlocked_ioctl = linereq_ioctl,
1673 #ifdef CONFIG_COMPAT
1674 .compat_ioctl = linereq_ioctl_compat,
1676 #ifdef CONFIG_PROC_FS
1677 .show_fdinfo = linereq_show_fdinfo,
1681 static int linereq_create(struct gpio_device *gdev, void __user *ip)
1683 struct gpio_v2_line_request ulr;
1684 struct gpio_v2_line_config *lc;
1691 if (copy_from_user(&ulr, ip, sizeof(ulr)))
1694 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1697 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
1701 ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1705 lr = kvzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
1708 lr->num_lines = ulr.num_lines;
1710 lr->gdev = gpio_device_get(gdev);
1712 for (i = 0; i < ulr.num_lines; i++) {
1713 lr->lines[i].req = lr;
1714 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1715 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1718 if (ulr.consumer[0] != '\0') {
1719 /* label is only initialized if consumer is set */
1720 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1724 goto out_free_linereq;
1728 mutex_init(&lr->config_mutex);
1729 init_waitqueue_head(&lr->wait);
1730 lr->event_buffer_size = ulr.event_buffer_size;
1731 if (lr->event_buffer_size == 0)
1732 lr->event_buffer_size = ulr.num_lines * 16;
1733 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1734 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1736 atomic_set(&lr->seqno, 0);
1738 /* Request each GPIO */
1739 for (i = 0; i < ulr.num_lines; i++) {
1740 u32 offset = ulr.offsets[i];
1741 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
1744 ret = PTR_ERR(desc);
1745 goto out_free_linereq;
1748 ret = gpiod_request_user(desc, lr->label);
1750 goto out_free_linereq;
1752 lr->lines[i].desc = desc;
1753 flags = gpio_v2_line_config_flags(lc, i);
1754 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1756 ret = gpiod_set_transitory(desc, false);
1758 goto out_free_linereq;
1760 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1762 * Lines have to be requested explicitly for input
1763 * or output, else the line will be treated "as is".
1765 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1766 int val = gpio_v2_line_config_output_value(lc, i);
1768 ret = gpiod_direction_output(desc, val);
1770 goto out_free_linereq;
1771 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1772 ret = gpiod_direction_input(desc);
1774 goto out_free_linereq;
1776 ret = edge_detector_setup(&lr->lines[i], lc, i,
1779 goto out_free_linereq;
1782 lr->lines[i].edflags = edflags;
1784 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
1786 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1790 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify;
1791 ret = blocking_notifier_chain_register(&gdev->device_notifier,
1792 &lr->device_unregistered_nb);
1794 goto out_free_linereq;
1796 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1799 goto out_free_linereq;
1802 file = anon_inode_getfile("gpio-line", &line_fileops, lr,
1803 O_RDONLY | O_CLOEXEC);
1805 ret = PTR_ERR(file);
1806 goto out_put_unused_fd;
1810 if (copy_to_user(ip, &ulr, sizeof(ulr))) {
1812 * fput() will trigger the release() callback, so do not go onto
1813 * the regular error cleanup path here.
1820 fd_install(fd, file);
1822 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1834 #ifdef CONFIG_GPIO_CDEV_V1
1837 * GPIO line event management
1841 * struct lineevent_state - contains the state of a userspace event
1842 * @gdev: the GPIO device the event pertains to
1843 * @label: consumer label used to tag descriptors
1844 * @desc: the GPIO descriptor held by this event
1845 * @eflags: the event flags this line was requested with
1846 * @irq: the interrupt that trigger in response to events on this GPIO
1847 * @wait: wait queue that handles blocking reads of events
1848 * @device_unregistered_nb: notifier block for receiving gdev unregister events
1849 * @events: KFIFO for the GPIO events
1850 * @timestamp: cache for the timestamp storing it between hardirq
1851 * and IRQ thread, used to bring the timestamp close to the actual
1854 struct lineevent_state {
1855 struct gpio_device *gdev;
1857 struct gpio_desc *desc;
1860 wait_queue_head_t wait;
1861 struct notifier_block device_unregistered_nb;
1862 DECLARE_KFIFO(events, struct gpioevent_data, 16);
1866 #define GPIOEVENT_REQUEST_VALID_FLAGS \
1867 (GPIOEVENT_REQUEST_RISING_EDGE | \
1868 GPIOEVENT_REQUEST_FALLING_EDGE)
1870 static __poll_t lineevent_poll(struct file *file,
1871 struct poll_table_struct *wait)
1873 struct lineevent_state *le = file->private_data;
1874 __poll_t events = 0;
1876 guard(srcu)(&le->gdev->srcu);
1878 if (!rcu_access_pointer(le->gdev->chip))
1879 return EPOLLHUP | EPOLLERR;
1881 poll_wait(file, &le->wait, wait);
1883 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1884 events = EPOLLIN | EPOLLRDNORM;
1889 static int lineevent_unregistered_notify(struct notifier_block *nb,
1890 unsigned long action, void *data)
1892 struct lineevent_state *le = container_of(nb, struct lineevent_state,
1893 device_unregistered_nb);
1895 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR);
1900 struct compat_gpioeevent_data {
1901 compat_u64 timestamp;
1905 static ssize_t lineevent_read(struct file *file, char __user *buf,
1906 size_t count, loff_t *f_ps)
1908 struct lineevent_state *le = file->private_data;
1909 struct gpioevent_data ge;
1910 ssize_t bytes_read = 0;
1914 guard(srcu)(&le->gdev->srcu);
1916 if (!rcu_access_pointer(le->gdev->chip))
1920 * When compatible system call is being used the struct gpioevent_data,
1921 * in case of at least ia32, has different size due to the alignment
1922 * differences. Because we have first member 64 bits followed by one of
1923 * 32 bits there is no gap between them. The only difference is the
1924 * padding at the end of the data structure. Hence, we calculate the
1925 * actual sizeof() and pass this as an argument to copy_to_user() to
1926 * drop unneeded bytes from the output.
1928 if (compat_need_64bit_alignment_fixup())
1929 ge_size = sizeof(struct compat_gpioeevent_data);
1931 ge_size = sizeof(struct gpioevent_data);
1932 if (count < ge_size)
1936 scoped_guard(spinlock, &le->wait.lock) {
1937 if (kfifo_is_empty(&le->events)) {
1941 if (file->f_flags & O_NONBLOCK)
1944 ret = wait_event_interruptible_locked(le->wait,
1945 !kfifo_is_empty(&le->events));
1950 ret = kfifo_out(&le->events, &ge, 1);
1954 * This should never happen - we were holding the lock
1955 * from the moment we learned the fifo is no longer
1962 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1964 bytes_read += ge_size;
1965 } while (count >= bytes_read + ge_size);
1970 static void lineevent_free(struct lineevent_state *le)
1972 if (le->device_unregistered_nb.notifier_call)
1973 blocking_notifier_chain_unregister(&le->gdev->device_notifier,
1974 &le->device_unregistered_nb);
1976 free_irq(le->irq, le);
1978 gpiod_free(le->desc);
1980 gpio_device_put(le->gdev);
1984 static int lineevent_release(struct inode *inode, struct file *file)
1986 lineevent_free(file->private_data);
1990 static long lineevent_ioctl(struct file *file, unsigned int cmd,
1993 struct lineevent_state *le = file->private_data;
1994 void __user *ip = (void __user *)arg;
1995 struct gpiohandle_data ghd;
1997 guard(srcu)(&le->gdev->srcu);
1999 if (!rcu_access_pointer(le->gdev->chip))
2003 * We can get the value for an event line but not set it,
2004 * because it is input by definition.
2006 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
2009 memset(&ghd, 0, sizeof(ghd));
2011 val = gpiod_get_value_cansleep(le->desc);
2014 ghd.values[0] = val;
2016 if (copy_to_user(ip, &ghd, sizeof(ghd)))
2024 #ifdef CONFIG_COMPAT
2025 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
2028 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2032 static const struct file_operations lineevent_fileops = {
2033 .release = lineevent_release,
2034 .read = lineevent_read,
2035 .poll = lineevent_poll,
2036 .owner = THIS_MODULE,
2037 .llseek = noop_llseek,
2038 .unlocked_ioctl = lineevent_ioctl,
2039 #ifdef CONFIG_COMPAT
2040 .compat_ioctl = lineevent_ioctl_compat,
2044 static irqreturn_t lineevent_irq_thread(int irq, void *p)
2046 struct lineevent_state *le = p;
2047 struct gpioevent_data ge;
2050 /* Do not leak kernel stack to userspace */
2051 memset(&ge, 0, sizeof(ge));
2054 * We may be running from a nested threaded interrupt in which case
2055 * we didn't get the timestamp from lineevent_irq_handler().
2058 ge.timestamp = ktime_get_ns();
2060 ge.timestamp = le->timestamp;
2062 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
2063 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2064 int level = gpiod_get_value_cansleep(le->desc);
2067 /* Emit low-to-high event */
2068 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2070 /* Emit high-to-low event */
2071 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2072 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
2073 /* Emit low-to-high event */
2074 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2075 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2076 /* Emit high-to-low event */
2077 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2082 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
2085 wake_up_poll(&le->wait, EPOLLIN);
2087 pr_debug_ratelimited("event FIFO is full - event dropped\n");
2092 static irqreturn_t lineevent_irq_handler(int irq, void *p)
2094 struct lineevent_state *le = p;
2097 * Just store the timestamp in hardirq context so we get it as
2098 * close in time as possible to the actual event.
2100 le->timestamp = ktime_get_ns();
2102 return IRQ_WAKE_THREAD;
2105 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
2107 struct gpioevent_request eventreq;
2108 struct lineevent_state *le;
2109 struct gpio_desc *desc;
2116 int irq, irqflags = 0;
2118 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
2121 offset = eventreq.lineoffset;
2122 lflags = eventreq.handleflags;
2123 eflags = eventreq.eventflags;
2125 desc = gpio_device_get_desc(gdev, offset);
2127 return PTR_ERR(desc);
2129 /* Return an error if a unknown flag is set */
2130 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
2131 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
2134 /* This is just wrong: we don't look for events on output lines */
2135 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
2136 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
2137 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
2140 /* Only one bias flag can be set. */
2141 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
2142 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
2143 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
2144 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
2145 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
2148 le = kzalloc(sizeof(*le), GFP_KERNEL);
2151 le->gdev = gpio_device_get(gdev);
2153 if (eventreq.consumer_label[0] != '\0') {
2154 /* label is only initialized if consumer_label is set */
2155 le->label = kstrndup(eventreq.consumer_label,
2156 sizeof(eventreq.consumer_label) - 1,
2164 ret = gpiod_request_user(desc, le->label);
2168 le->eflags = eflags;
2170 linehandle_flags_to_desc_flags(lflags, &desc->flags);
2172 ret = gpiod_direction_input(desc);
2176 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
2178 irq = gpiod_to_irq(desc);
2184 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
2185 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2186 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
2187 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
2188 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2189 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
2190 irqflags |= IRQF_ONESHOT;
2192 INIT_KFIFO(le->events);
2193 init_waitqueue_head(&le->wait);
2195 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify;
2196 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2197 &le->device_unregistered_nb);
2201 /* Request a thread to read the events */
2202 ret = request_threaded_irq(irq,
2203 lineevent_irq_handler,
2204 lineevent_irq_thread,
2213 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
2219 file = anon_inode_getfile("gpio-event",
2222 O_RDONLY | O_CLOEXEC);
2224 ret = PTR_ERR(file);
2225 goto out_put_unused_fd;
2229 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
2231 * fput() will trigger the release() callback, so do not go onto
2232 * the regular error cleanup path here.
2239 fd_install(fd, file);
2250 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
2251 struct gpioline_info *info_v1)
2253 u64 flagsv2 = info_v2->flags;
2255 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
2256 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
2257 info_v1->line_offset = info_v2->offset;
2260 if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
2261 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
2263 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
2264 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
2266 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
2267 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
2269 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
2270 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
2271 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
2272 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
2274 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
2275 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
2276 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
2277 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
2278 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
2279 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
2282 static void gpio_v2_line_info_changed_to_v1(
2283 struct gpio_v2_line_info_changed *lic_v2,
2284 struct gpioline_info_changed *lic_v1)
2286 memset(lic_v1, 0, sizeof(*lic_v1));
2287 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
2288 lic_v1->timestamp = lic_v2->timestamp_ns;
2289 lic_v1->event_type = lic_v2->event_type;
2292 #endif /* CONFIG_GPIO_CDEV_V1 */
2294 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
2295 struct gpio_v2_line_info *info)
2297 unsigned long dflags;
2300 CLASS(gpio_chip_guard, guard)(desc);
2304 memset(info, 0, sizeof(*info));
2305 info->offset = gpio_chip_hwgpio(desc);
2308 strscpy(info->name, desc->name, sizeof(info->name));
2310 dflags = READ_ONCE(desc->flags);
2312 scoped_guard(srcu, &desc->srcu) {
2313 label = gpiod_get_label(desc);
2314 if (label && test_bit(FLAG_REQUESTED, &dflags))
2315 strscpy(info->consumer, label,
2316 sizeof(info->consumer));
2320 * Userspace only need know that the kernel is using this GPIO so it
2322 * The calculation of the used flag is slightly racy, as it may read
2323 * desc, gc and pinctrl state without a lock covering all three at
2324 * once. Worst case if the line is in transition and the calculation
2325 * is inconsistent then it looks to the user like they performed the
2326 * read on the other side of the transition - but that can always
2328 * The definitive test that a line is available to userspace is to
2331 if (test_bit(FLAG_REQUESTED, &dflags) ||
2332 test_bit(FLAG_IS_HOGGED, &dflags) ||
2333 test_bit(FLAG_USED_AS_IRQ, &dflags) ||
2334 test_bit(FLAG_EXPORT, &dflags) ||
2335 test_bit(FLAG_SYSFS, &dflags) ||
2336 !gpiochip_line_is_valid(guard.gc, info->offset) ||
2337 !pinctrl_gpio_can_use_line(guard.gc, info->offset))
2338 info->flags |= GPIO_V2_LINE_FLAG_USED;
2340 if (test_bit(FLAG_IS_OUT, &dflags))
2341 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
2343 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
2345 if (test_bit(FLAG_ACTIVE_LOW, &dflags))
2346 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
2348 if (test_bit(FLAG_OPEN_DRAIN, &dflags))
2349 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
2350 if (test_bit(FLAG_OPEN_SOURCE, &dflags))
2351 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
2353 if (test_bit(FLAG_BIAS_DISABLE, &dflags))
2354 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
2355 if (test_bit(FLAG_PULL_DOWN, &dflags))
2356 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
2357 if (test_bit(FLAG_PULL_UP, &dflags))
2358 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
2360 if (test_bit(FLAG_EDGE_RISING, &dflags))
2361 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
2362 if (test_bit(FLAG_EDGE_FALLING, &dflags))
2363 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
2365 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &dflags))
2366 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
2367 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags))
2368 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
2371 struct gpio_chardev_data {
2372 struct gpio_device *gdev;
2373 wait_queue_head_t wait;
2374 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
2375 struct notifier_block lineinfo_changed_nb;
2376 struct notifier_block device_unregistered_nb;
2377 unsigned long *watched_lines;
2378 #ifdef CONFIG_GPIO_CDEV_V1
2379 atomic_t watch_abi_version;
2383 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
2385 struct gpio_device *gdev = cdev->gdev;
2386 struct gpiochip_info chipinfo;
2388 memset(&chipinfo, 0, sizeof(chipinfo));
2390 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
2391 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
2392 chipinfo.lines = gdev->ngpio;
2393 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
2398 #ifdef CONFIG_GPIO_CDEV_V1
2400 * returns 0 if the versions match, else the previously selected ABI version
2402 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
2403 unsigned int version)
2405 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
2407 if (abiv == version)
2413 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
2416 struct gpio_desc *desc;
2417 struct gpioline_info lineinfo;
2418 struct gpio_v2_line_info lineinfo_v2;
2420 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2423 /* this doubles as a range check on line_offset */
2424 desc = gpio_device_get_desc(cdev->gdev, lineinfo.line_offset);
2426 return PTR_ERR(desc);
2429 if (lineinfo_ensure_abi_version(cdev, 1))
2432 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2436 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2437 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2439 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2441 clear_bit(lineinfo.line_offset, cdev->watched_lines);
2449 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
2452 struct gpio_desc *desc;
2453 struct gpio_v2_line_info lineinfo;
2455 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2458 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
2461 desc = gpio_device_get_desc(cdev->gdev, lineinfo.offset);
2463 return PTR_ERR(desc);
2466 #ifdef CONFIG_GPIO_CDEV_V1
2467 if (lineinfo_ensure_abi_version(cdev, 2))
2470 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2473 gpio_desc_to_lineinfo(desc, &lineinfo);
2474 supinfo_to_lineinfo(desc, &lineinfo);
2476 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2478 clear_bit(lineinfo.offset, cdev->watched_lines);
2485 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
2489 if (copy_from_user(&offset, ip, sizeof(offset)))
2492 if (offset >= cdev->gdev->ngpio)
2495 if (!test_and_clear_bit(offset, cdev->watched_lines))
2502 * gpio_ioctl() - ioctl handler for the GPIO chardev
2504 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2506 struct gpio_chardev_data *cdev = file->private_data;
2507 struct gpio_device *gdev = cdev->gdev;
2508 void __user *ip = (void __user *)arg;
2510 guard(srcu)(&gdev->srcu);
2512 /* We fail any subsequent ioctl():s when the chip is gone */
2513 if (!rcu_access_pointer(gdev->chip))
2516 /* Fill in the struct and pass to userspace */
2518 case GPIO_GET_CHIPINFO_IOCTL:
2519 return chipinfo_get(cdev, ip);
2520 #ifdef CONFIG_GPIO_CDEV_V1
2521 case GPIO_GET_LINEHANDLE_IOCTL:
2522 return linehandle_create(gdev, ip);
2523 case GPIO_GET_LINEEVENT_IOCTL:
2524 return lineevent_create(gdev, ip);
2525 case GPIO_GET_LINEINFO_IOCTL:
2526 return lineinfo_get_v1(cdev, ip, false);
2527 case GPIO_GET_LINEINFO_WATCH_IOCTL:
2528 return lineinfo_get_v1(cdev, ip, true);
2529 #endif /* CONFIG_GPIO_CDEV_V1 */
2530 case GPIO_V2_GET_LINEINFO_IOCTL:
2531 return lineinfo_get(cdev, ip, false);
2532 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
2533 return lineinfo_get(cdev, ip, true);
2534 case GPIO_V2_GET_LINE_IOCTL:
2535 return linereq_create(gdev, ip);
2536 case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
2537 return lineinfo_unwatch(cdev, ip);
2543 #ifdef CONFIG_COMPAT
2544 static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2547 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2551 static int lineinfo_changed_notify(struct notifier_block *nb,
2552 unsigned long action, void *data)
2554 struct gpio_chardev_data *cdev =
2555 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2556 struct gpio_v2_line_info_changed chg;
2557 struct gpio_desc *desc = data;
2560 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
2563 memset(&chg, 0, sizeof(chg));
2564 chg.event_type = action;
2565 chg.timestamp_ns = ktime_get_ns();
2566 gpio_desc_to_lineinfo(desc, &chg.info);
2567 supinfo_to_lineinfo(desc, &chg.info);
2569 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
2571 wake_up_poll(&cdev->wait, EPOLLIN);
2573 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2578 static int gpio_device_unregistered_notify(struct notifier_block *nb,
2579 unsigned long action, void *data)
2581 struct gpio_chardev_data *cdev = container_of(nb,
2582 struct gpio_chardev_data,
2583 device_unregistered_nb);
2585 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR);
2590 static __poll_t lineinfo_watch_poll(struct file *file,
2591 struct poll_table_struct *pollt)
2593 struct gpio_chardev_data *cdev = file->private_data;
2594 __poll_t events = 0;
2596 guard(srcu)(&cdev->gdev->srcu);
2598 if (!rcu_access_pointer(cdev->gdev->chip))
2599 return EPOLLHUP | EPOLLERR;
2601 poll_wait(file, &cdev->wait, pollt);
2603 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2605 events = EPOLLIN | EPOLLRDNORM;
2610 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2611 size_t count, loff_t *off)
2613 struct gpio_chardev_data *cdev = file->private_data;
2614 struct gpio_v2_line_info_changed event;
2615 ssize_t bytes_read = 0;
2619 guard(srcu)(&cdev->gdev->srcu);
2621 if (!rcu_access_pointer(cdev->gdev->chip))
2624 #ifndef CONFIG_GPIO_CDEV_V1
2625 event_size = sizeof(struct gpio_v2_line_info_changed);
2626 if (count < event_size)
2631 scoped_guard(spinlock, &cdev->wait.lock) {
2632 if (kfifo_is_empty(&cdev->events)) {
2636 if (file->f_flags & O_NONBLOCK)
2639 ret = wait_event_interruptible_locked(cdev->wait,
2640 !kfifo_is_empty(&cdev->events));
2644 #ifdef CONFIG_GPIO_CDEV_V1
2645 /* must be after kfifo check so watch_abi_version is set */
2646 if (atomic_read(&cdev->watch_abi_version) == 2)
2647 event_size = sizeof(struct gpio_v2_line_info_changed);
2649 event_size = sizeof(struct gpioline_info_changed);
2650 if (count < event_size)
2653 ret = kfifo_out(&cdev->events, &event, 1);
2658 /* We should never get here. See lineevent_read(). */
2661 #ifdef CONFIG_GPIO_CDEV_V1
2662 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2663 if (copy_to_user(buf + bytes_read, &event, event_size))
2666 struct gpioline_info_changed event_v1;
2668 gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2669 if (copy_to_user(buf + bytes_read, &event_v1,
2674 if (copy_to_user(buf + bytes_read, &event, event_size))
2677 bytes_read += event_size;
2678 } while (count >= bytes_read + sizeof(event));
2684 * gpio_chrdev_open() - open the chardev for ioctl operations
2685 * @inode: inode for this chardev
2686 * @file: file struct for storing private data
2687 * Returns 0 on success
2689 static int gpio_chrdev_open(struct inode *inode, struct file *file)
2691 struct gpio_device *gdev = container_of(inode->i_cdev,
2692 struct gpio_device, chrdev);
2693 struct gpio_chardev_data *cdev;
2696 guard(srcu)(&gdev->srcu);
2698 /* Fail on open if the backing gpiochip is gone */
2699 if (!rcu_access_pointer(gdev->chip))
2702 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2706 cdev->watched_lines = bitmap_zalloc(gdev->ngpio, GFP_KERNEL);
2707 if (!cdev->watched_lines)
2710 init_waitqueue_head(&cdev->wait);
2711 INIT_KFIFO(cdev->events);
2712 cdev->gdev = gpio_device_get(gdev);
2714 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2715 ret = blocking_notifier_chain_register(&gdev->line_state_notifier,
2716 &cdev->lineinfo_changed_nb);
2718 goto out_free_bitmap;
2720 cdev->device_unregistered_nb.notifier_call =
2721 gpio_device_unregistered_notify;
2722 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2723 &cdev->device_unregistered_nb);
2725 goto out_unregister_line_notifier;
2727 file->private_data = cdev;
2729 ret = nonseekable_open(inode, file);
2731 goto out_unregister_device_notifier;
2735 out_unregister_device_notifier:
2736 blocking_notifier_chain_unregister(&gdev->device_notifier,
2737 &cdev->device_unregistered_nb);
2738 out_unregister_line_notifier:
2739 blocking_notifier_chain_unregister(&gdev->line_state_notifier,
2740 &cdev->lineinfo_changed_nb);
2742 gpio_device_put(gdev);
2743 bitmap_free(cdev->watched_lines);
2750 * gpio_chrdev_release() - close chardev after ioctl operations
2751 * @inode: inode for this chardev
2752 * @file: file struct for storing private data
2753 * Returns 0 on success
2755 static int gpio_chrdev_release(struct inode *inode, struct file *file)
2757 struct gpio_chardev_data *cdev = file->private_data;
2758 struct gpio_device *gdev = cdev->gdev;
2760 bitmap_free(cdev->watched_lines);
2761 blocking_notifier_chain_unregister(&gdev->device_notifier,
2762 &cdev->device_unregistered_nb);
2763 blocking_notifier_chain_unregister(&gdev->line_state_notifier,
2764 &cdev->lineinfo_changed_nb);
2765 gpio_device_put(gdev);
2771 static const struct file_operations gpio_fileops = {
2772 .release = gpio_chrdev_release,
2773 .open = gpio_chrdev_open,
2774 .poll = lineinfo_watch_poll,
2775 .read = lineinfo_watch_read,
2776 .owner = THIS_MODULE,
2777 .llseek = no_llseek,
2778 .unlocked_ioctl = gpio_ioctl,
2779 #ifdef CONFIG_COMPAT
2780 .compat_ioctl = gpio_ioctl_compat,
2784 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
2786 struct gpio_chip *gc;
2789 cdev_init(&gdev->chrdev, &gpio_fileops);
2790 gdev->chrdev.owner = THIS_MODULE;
2791 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2793 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2797 guard(srcu)(&gdev->srcu);
2798 gc = srcu_dereference(gdev->chip, &gdev->srcu);
2802 chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
2807 void gpiolib_cdev_unregister(struct gpio_device *gdev)
2809 cdev_device_del(&gdev->chrdev, &gdev->dev);
2810 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL);