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/rwsem.h>
28 #include <linux/seq_file.h>
29 #include <linux/spinlock.h>
30 #include <linux/timekeeping.h>
31 #include <linux/uaccess.h>
32 #include <linux/workqueue.h>
34 #include <uapi/linux/gpio.h>
37 #include "gpiolib-cdev.h"
40 * Array sizes must ensure 64-bit alignment and not create holes in the
43 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
44 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
47 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
50 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
51 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
52 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
53 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
54 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
55 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
56 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
58 /* Character device interface to GPIO.
60 * The GPIO character device, /dev/gpiochipN, provides userspace an
61 * interface to gpiolib GPIOs via ioctl()s.
64 typedef __poll_t (*poll_fn)(struct file *, struct poll_table_struct *);
65 typedef long (*ioctl_fn)(struct file *, unsigned int, unsigned long);
66 typedef ssize_t (*read_fn)(struct file *, char __user *,
67 size_t count, loff_t *);
70 * GPIO line handle management
73 #ifdef CONFIG_GPIO_CDEV_V1
75 * struct linehandle_state - contains the state of a userspace handle
76 * @gdev: the GPIO device the handle pertains to
77 * @label: consumer label used to tag descriptors
78 * @descs: the GPIO descriptors held by this handle
79 * @num_descs: the number of descriptors held in the descs array
81 struct linehandle_state {
82 struct gpio_device *gdev;
84 struct gpio_desc *descs[GPIOHANDLES_MAX];
88 #define GPIOHANDLE_REQUEST_VALID_FLAGS \
89 (GPIOHANDLE_REQUEST_INPUT | \
90 GPIOHANDLE_REQUEST_OUTPUT | \
91 GPIOHANDLE_REQUEST_ACTIVE_LOW | \
92 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
93 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
94 GPIOHANDLE_REQUEST_BIAS_DISABLE | \
95 GPIOHANDLE_REQUEST_OPEN_DRAIN | \
96 GPIOHANDLE_REQUEST_OPEN_SOURCE)
98 static int linehandle_validate_flags(u32 flags)
100 /* Return an error if an unknown flag is set */
101 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
105 * Do not allow both INPUT & OUTPUT flags to be set as they are
108 if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
109 (flags & GPIOHANDLE_REQUEST_OUTPUT))
113 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
114 * the hardware actually supports enabling both at the same time the
115 * electrical result would be disastrous.
117 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
118 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
121 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
122 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
123 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
124 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
127 /* Bias flags only allowed for input or output mode. */
128 if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
129 (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
130 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
131 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
132 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
135 /* Only one bias flag can be set. */
136 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
137 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
138 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
139 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
140 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
146 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
148 assign_bit(FLAG_ACTIVE_LOW, flagsp,
149 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
150 assign_bit(FLAG_OPEN_DRAIN, flagsp,
151 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
152 assign_bit(FLAG_OPEN_SOURCE, flagsp,
153 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
154 assign_bit(FLAG_PULL_UP, flagsp,
155 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
156 assign_bit(FLAG_PULL_DOWN, flagsp,
157 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
158 assign_bit(FLAG_BIAS_DISABLE, flagsp,
159 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
162 static long linehandle_set_config(struct linehandle_state *lh,
165 struct gpiohandle_config gcnf;
166 struct gpio_desc *desc;
170 if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
174 ret = linehandle_validate_flags(lflags);
178 for (i = 0; i < lh->num_descs; i++) {
180 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
183 * Lines have to be requested explicitly for input
184 * or output, else the line will be treated "as is".
186 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
187 int val = !!gcnf.default_values[i];
189 ret = gpiod_direction_output(desc, val);
192 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
193 ret = gpiod_direction_input(desc);
198 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
203 static long linehandle_ioctl(struct file *file, unsigned int cmd,
206 struct linehandle_state *lh = file->private_data;
207 void __user *ip = (void __user *)arg;
208 struct gpiohandle_data ghd;
209 DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
213 guard(rwsem_read)(&lh->gdev->sem);
219 case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
220 /* NOTE: It's okay to read values of output lines */
221 ret = gpiod_get_array_value_complex(false, true,
222 lh->num_descs, lh->descs,
227 memset(&ghd, 0, sizeof(ghd));
228 for (i = 0; i < lh->num_descs; i++)
229 ghd.values[i] = test_bit(i, vals);
231 if (copy_to_user(ip, &ghd, sizeof(ghd)))
235 case GPIOHANDLE_SET_LINE_VALUES_IOCTL:
237 * All line descriptors were created at once with the same
238 * flags so just check if the first one is really output.
240 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
243 if (copy_from_user(&ghd, ip, sizeof(ghd)))
246 /* Clamp all values to [0,1] */
247 for (i = 0; i < lh->num_descs; i++)
248 __assign_bit(i, vals, ghd.values[i]);
250 /* Reuse the array setting function */
251 return gpiod_set_array_value_complex(false,
257 case GPIOHANDLE_SET_CONFIG_IOCTL:
258 return linehandle_set_config(lh, ip);
265 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
268 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
272 static void linehandle_free(struct linehandle_state *lh)
276 for (i = 0; i < lh->num_descs; i++)
278 gpiod_free(lh->descs[i]);
280 gpio_device_put(lh->gdev);
284 static int linehandle_release(struct inode *inode, struct file *file)
286 linehandle_free(file->private_data);
290 static const struct file_operations linehandle_fileops = {
291 .release = linehandle_release,
292 .owner = THIS_MODULE,
293 .llseek = noop_llseek,
294 .unlocked_ioctl = linehandle_ioctl,
296 .compat_ioctl = linehandle_ioctl_compat,
300 static int linehandle_create(struct gpio_device *gdev, void __user *ip)
302 struct gpiohandle_request handlereq;
303 struct linehandle_state *lh;
308 if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
310 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
313 lflags = handlereq.flags;
315 ret = linehandle_validate_flags(lflags);
319 lh = kzalloc(sizeof(*lh), GFP_KERNEL);
322 lh->gdev = gpio_device_get(gdev);
324 if (handlereq.consumer_label[0] != '\0') {
325 /* label is only initialized if consumer_label is set */
326 lh->label = kstrndup(handlereq.consumer_label,
327 sizeof(handlereq.consumer_label) - 1,
335 lh->num_descs = handlereq.lines;
337 /* Request each GPIO */
338 for (i = 0; i < handlereq.lines; i++) {
339 u32 offset = handlereq.lineoffsets[i];
340 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
347 ret = gpiod_request_user(desc, lh->label);
351 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
353 ret = gpiod_set_transitory(desc, false);
358 * Lines have to be requested explicitly for input
359 * or output, else the line will be treated "as is".
361 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
362 int val = !!handlereq.default_values[i];
364 ret = gpiod_direction_output(desc, val);
367 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
368 ret = gpiod_direction_input(desc);
373 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
375 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
379 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
385 file = anon_inode_getfile("gpio-linehandle",
388 O_RDONLY | O_CLOEXEC);
391 goto out_put_unused_fd;
395 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
397 * fput() will trigger the release() callback, so do not go onto
398 * the regular error cleanup path here.
405 fd_install(fd, file);
407 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
418 #endif /* CONFIG_GPIO_CDEV_V1 */
421 * struct line - contains the state of a requested line
422 * @node: to store the object in supinfo_tree if supplemental
423 * @desc: the GPIO descriptor for this line.
424 * @req: the corresponding line request
425 * @irq: the interrupt triggered in response to events on this GPIO
426 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
427 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
428 * @timestamp_ns: cache for the timestamp storing it between hardirq and
429 * IRQ thread, used to bring the timestamp close to the actual event
430 * @req_seqno: the seqno for the current edge event in the sequence of
431 * events for the corresponding line request. This is drawn from the @req.
432 * @line_seqno: the seqno for the current edge event in the sequence of
433 * events for this line.
434 * @work: the worker that implements software debouncing
435 * @debounce_period_us: the debounce period in microseconds
436 * @sw_debounced: flag indicating if the software debouncer is active
437 * @level: the current debounced physical level of the line
438 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
439 * @raw_level: the line level at the time of event
440 * @total_discard_seq: the running counter of the discarded events
441 * @last_seqno: the last sequence number before debounce period expires
445 struct gpio_desc *desc;
447 * -- edge detector specific fields --
452 * The flags for the active edge detector configuration.
454 * edflags is set by linereq_create(), linereq_free(), and
455 * linereq_set_config_unlocked(), which are themselves mutually
456 * exclusive, and is accessed by edge_irq_thread(),
457 * process_hw_ts_thread() and debounce_work_func(),
458 * which can all live with a slightly stale value.
462 * timestamp_ns and req_seqno are accessed only by
463 * edge_irq_handler() and edge_irq_thread(), which are themselves
464 * mutually exclusive, so no additional protection is necessary.
469 * line_seqno is accessed by either edge_irq_thread() or
470 * debounce_work_func(), which are themselves mutually exclusive,
471 * so no additional protection is necessary.
475 * -- debouncer specific fields --
477 struct delayed_work work;
479 * debounce_period_us is accessed by debounce_irq_handler() and
480 * process_hw_ts() which are disabled when modified by
481 * debounce_setup(), edge_detector_setup() or edge_detector_stop()
482 * or can live with a stale version when updated by
483 * edge_detector_update().
484 * The modifying functions are themselves mutually exclusive.
486 unsigned int debounce_period_us;
488 * sw_debounce is accessed by linereq_set_config(), which is the
489 * only setter, and linereq_get_values(), which can live with a
490 * slightly stale value.
492 unsigned int sw_debounced;
494 * level is accessed by debounce_work_func(), which is the only
495 * setter, and linereq_get_values() which can live with a slightly
500 struct hte_ts_desc hdesc;
502 * HTE provider sets line level at the time of event. The valid
503 * value is 0 or 1 and negative value for an error.
507 * when sw_debounce is set on HTE enabled line, this is running
508 * counter of the discarded events.
510 u32 total_discard_seq;
512 * when sw_debounce is set on HTE enabled line, this variable records
513 * last sequence number before debounce period expires.
516 #endif /* CONFIG_HTE */
520 * a rbtree of the struct lines containing supplemental info.
521 * Used to populate gpio_v2_line_info with cdev specific fields not contained
522 * in the struct gpio_desc.
523 * A line is determined to contain supplemental information by
524 * line_has_supinfo().
526 static struct rb_root supinfo_tree = RB_ROOT;
527 /* covers supinfo_tree */
528 static DEFINE_SPINLOCK(supinfo_lock);
531 * struct linereq - contains the state of a userspace line request
532 * @gdev: the GPIO device the line request pertains to
533 * @label: consumer label used to tag GPIO descriptors
534 * @num_lines: the number of lines in the lines array
535 * @wait: wait queue that handles blocking reads of events
536 * @device_unregistered_nb: notifier block for receiving gdev unregister events
537 * @event_buffer_size: the number of elements allocated in @events
538 * @events: KFIFO for the GPIO events
539 * @seqno: the sequence number for edge events generated on all lines in
540 * this line request. Note that this is not used when @num_lines is 1, as
541 * the line_seqno is then the same and is cheaper to calculate.
542 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
543 * of configuration, particularly multi-step accesses to desc flags and
544 * changes to supinfo status.
545 * @lines: the lines held by this line request, with @num_lines elements.
548 struct gpio_device *gdev;
551 wait_queue_head_t wait;
552 struct notifier_block device_unregistered_nb;
553 u32 event_buffer_size;
554 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
556 struct mutex config_mutex;
557 struct line lines[] __counted_by(num_lines);
560 static void supinfo_insert(struct line *line)
562 struct rb_node **new = &(supinfo_tree.rb_node), *parent = NULL;
565 guard(spinlock)(&supinfo_lock);
568 entry = container_of(*new, struct line, node);
571 if (line->desc < entry->desc) {
572 new = &((*new)->rb_left);
573 } else if (line->desc > entry->desc) {
574 new = &((*new)->rb_right);
576 /* this should never happen */
577 WARN(1, "duplicate line inserted");
582 rb_link_node(&line->node, parent, new);
583 rb_insert_color(&line->node, &supinfo_tree);
586 static void supinfo_erase(struct line *line)
588 guard(spinlock)(&supinfo_lock);
590 rb_erase(&line->node, &supinfo_tree);
593 static struct line *supinfo_find(struct gpio_desc *desc)
595 struct rb_node *node = supinfo_tree.rb_node;
599 line = container_of(node, struct line, node);
600 if (desc < line->desc)
601 node = node->rb_left;
602 else if (desc > line->desc)
603 node = node->rb_right;
610 static void supinfo_to_lineinfo(struct gpio_desc *desc,
611 struct gpio_v2_line_info *info)
613 struct gpio_v2_line_attribute *attr;
616 guard(spinlock)(&supinfo_lock);
618 line = supinfo_find(desc);
622 attr = &info->attrs[info->num_attrs];
623 attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
624 attr->debounce_period_us = READ_ONCE(line->debounce_period_us);
628 static inline bool line_has_supinfo(struct line *line)
630 return READ_ONCE(line->debounce_period_us);
634 * Checks line_has_supinfo() before and after the change to avoid unnecessary
635 * supinfo_tree access.
636 * Called indirectly by linereq_create() or linereq_set_config() so line
637 * is already protected from concurrent changes.
639 static void line_set_debounce_period(struct line *line,
640 unsigned int debounce_period_us)
642 bool was_suppl = line_has_supinfo(line);
644 WRITE_ONCE(line->debounce_period_us, debounce_period_us);
646 /* if supinfo status is unchanged then we're done */
647 if (line_has_supinfo(line) == was_suppl)
650 /* supinfo status has changed, so update the tree */
654 supinfo_insert(line);
657 #define GPIO_V2_LINE_BIAS_FLAGS \
658 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
659 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
660 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
662 #define GPIO_V2_LINE_DIRECTION_FLAGS \
663 (GPIO_V2_LINE_FLAG_INPUT | \
664 GPIO_V2_LINE_FLAG_OUTPUT)
666 #define GPIO_V2_LINE_DRIVE_FLAGS \
667 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
668 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
670 #define GPIO_V2_LINE_EDGE_FLAGS \
671 (GPIO_V2_LINE_FLAG_EDGE_RISING | \
672 GPIO_V2_LINE_FLAG_EDGE_FALLING)
674 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
676 #define GPIO_V2_LINE_VALID_FLAGS \
677 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
678 GPIO_V2_LINE_DIRECTION_FLAGS | \
679 GPIO_V2_LINE_DRIVE_FLAGS | \
680 GPIO_V2_LINE_EDGE_FLAGS | \
681 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
682 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
683 GPIO_V2_LINE_BIAS_FLAGS)
685 /* subset of flags relevant for edge detector configuration */
686 #define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
687 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
688 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
689 GPIO_V2_LINE_EDGE_FLAGS)
691 static int linereq_unregistered_notify(struct notifier_block *nb,
692 unsigned long action, void *data)
694 struct linereq *lr = container_of(nb, struct linereq,
695 device_unregistered_nb);
697 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR);
702 static void linereq_put_event(struct linereq *lr,
703 struct gpio_v2_line_event *le)
705 bool overflow = false;
707 scoped_guard(spinlock, &lr->wait.lock) {
708 if (kfifo_is_full(&lr->events)) {
710 kfifo_skip(&lr->events);
712 kfifo_in(&lr->events, le, 1);
715 wake_up_poll(&lr->wait, EPOLLIN);
717 pr_debug_ratelimited("event FIFO is full - event dropped\n");
720 static u64 line_event_timestamp(struct line *line)
722 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
723 return ktime_get_real_ns();
724 else if (IS_ENABLED(CONFIG_HTE) &&
725 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
726 return line->timestamp_ns;
728 return ktime_get_ns();
731 static u32 line_event_id(int level)
733 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
734 GPIO_V2_LINE_EVENT_FALLING_EDGE;
737 static inline char *make_irq_label(const char *orig)
744 new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL);
746 return ERR_PTR(-ENOMEM);
751 static inline void free_irq_label(const char *label)
758 static enum hte_return process_hw_ts_thread(void *p)
762 struct gpio_v2_line_event le;
767 return HTE_CB_HANDLED;
772 memset(&le, 0, sizeof(le));
774 le.timestamp_ns = line->timestamp_ns;
775 edflags = READ_ONCE(line->edflags);
777 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
778 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
779 level = (line->raw_level >= 0) ?
781 gpiod_get_raw_value_cansleep(line->desc);
783 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
786 le.id = line_event_id(level);
788 case GPIO_V2_LINE_FLAG_EDGE_RISING:
789 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
791 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
792 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
795 return HTE_CB_HANDLED;
797 le.line_seqno = line->line_seqno;
798 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
799 le.offset = gpio_chip_hwgpio(line->desc);
801 linereq_put_event(lr, &le);
803 return HTE_CB_HANDLED;
806 static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
813 return HTE_CB_HANDLED;
816 line->timestamp_ns = ts->tsc;
817 line->raw_level = ts->raw_level;
820 if (READ_ONCE(line->sw_debounced)) {
821 line->total_discard_seq++;
822 line->last_seqno = ts->seq;
823 mod_delayed_work(system_wq, &line->work,
824 usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
826 if (unlikely(ts->seq < line->line_seqno))
827 return HTE_CB_HANDLED;
829 diff_seqno = ts->seq - line->line_seqno;
830 line->line_seqno = ts->seq;
831 if (lr->num_lines != 1)
832 line->req_seqno = atomic_add_return(diff_seqno,
835 return HTE_RUN_SECOND_CB;
838 return HTE_CB_HANDLED;
841 static int hte_edge_setup(struct line *line, u64 eflags)
844 unsigned long flags = 0;
845 struct hte_ts_desc *hdesc = &line->hdesc;
847 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
848 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
849 HTE_FALLING_EDGE_TS :
851 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
852 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
856 line->total_discard_seq = 0;
858 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
861 ret = hte_ts_get(NULL, hdesc, 0);
865 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
871 static int hte_edge_setup(struct line *line, u64 eflags)
875 #endif /* CONFIG_HTE */
877 static irqreturn_t edge_irq_thread(int irq, void *p)
879 struct line *line = p;
880 struct linereq *lr = line->req;
881 struct gpio_v2_line_event le;
883 /* Do not leak kernel stack to userspace */
884 memset(&le, 0, sizeof(le));
886 if (line->timestamp_ns) {
887 le.timestamp_ns = line->timestamp_ns;
890 * We may be running from a nested threaded interrupt in
891 * which case we didn't get the timestamp from
892 * edge_irq_handler().
894 le.timestamp_ns = line_event_timestamp(line);
895 if (lr->num_lines != 1)
896 line->req_seqno = atomic_inc_return(&lr->seqno);
898 line->timestamp_ns = 0;
900 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
901 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
902 le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
904 case GPIO_V2_LINE_FLAG_EDGE_RISING:
905 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
907 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
908 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
914 le.line_seqno = line->line_seqno;
915 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
916 le.offset = gpio_chip_hwgpio(line->desc);
918 linereq_put_event(lr, &le);
923 static irqreturn_t edge_irq_handler(int irq, void *p)
925 struct line *line = p;
926 struct linereq *lr = line->req;
929 * Just store the timestamp in hardirq context so we get it as
930 * close in time as possible to the actual event.
932 line->timestamp_ns = line_event_timestamp(line);
934 if (lr->num_lines != 1)
935 line->req_seqno = atomic_inc_return(&lr->seqno);
937 return IRQ_WAKE_THREAD;
941 * returns the current debounced logical value.
943 static bool debounced_value(struct line *line)
948 * minor race - debouncer may be stopped here, so edge_detector_stop()
949 * must leave the value unchanged so the following will read the level
950 * from when the debouncer was last running.
952 value = READ_ONCE(line->level);
954 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
960 static irqreturn_t debounce_irq_handler(int irq, void *p)
962 struct line *line = p;
964 mod_delayed_work(system_wq, &line->work,
965 usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
970 static void debounce_work_func(struct work_struct *work)
972 struct gpio_v2_line_event le;
973 struct line *line = container_of(work, struct line, work.work);
975 u64 eflags, edflags = READ_ONCE(line->edflags);
980 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
981 level = line->raw_level;
984 level = gpiod_get_raw_value_cansleep(line->desc);
986 pr_debug_ratelimited("debouncer failed to read line value\n");
990 if (READ_ONCE(line->level) == level)
993 WRITE_ONCE(line->level, level);
995 /* -- edge detection -- */
996 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
1000 /* switch from physical level to logical - if they differ */
1001 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
1004 /* ignore edges that are not being monitored */
1005 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
1006 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
1009 /* Do not leak kernel stack to userspace */
1010 memset(&le, 0, sizeof(le));
1013 le.timestamp_ns = line_event_timestamp(line);
1014 le.offset = gpio_chip_hwgpio(line->desc);
1016 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
1017 /* discard events except the last one */
1018 line->total_discard_seq -= 1;
1019 diff_seqno = line->last_seqno - line->total_discard_seq -
1021 line->line_seqno = line->last_seqno - line->total_discard_seq;
1022 le.line_seqno = line->line_seqno;
1023 le.seqno = (lr->num_lines == 1) ?
1024 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
1026 #endif /* CONFIG_HTE */
1029 le.line_seqno = line->line_seqno;
1030 le.seqno = (lr->num_lines == 1) ?
1031 le.line_seqno : atomic_inc_return(&lr->seqno);
1034 le.id = line_event_id(level);
1036 linereq_put_event(lr, &le);
1039 static int debounce_setup(struct line *line, unsigned int debounce_period_us)
1041 unsigned long irqflags;
1042 int ret, level, irq;
1046 ret = gpiod_set_debounce(line->desc, debounce_period_us);
1048 line_set_debounce_period(line, debounce_period_us);
1051 if (ret != -ENOTSUPP)
1054 if (debounce_period_us) {
1055 /* setup software debounce */
1056 level = gpiod_get_raw_value_cansleep(line->desc);
1060 if (!(IS_ENABLED(CONFIG_HTE) &&
1061 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
1062 irq = gpiod_to_irq(line->desc);
1066 label = make_irq_label(line->req->label);
1070 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
1071 ret = request_irq(irq, debounce_irq_handler, irqflags,
1074 free_irq_label(label);
1079 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
1084 WRITE_ONCE(line->level, level);
1085 WRITE_ONCE(line->sw_debounced, 1);
1090 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
1091 unsigned int line_idx)
1094 u64 mask = BIT_ULL(line_idx);
1096 for (i = 0; i < lc->num_attrs; i++) {
1097 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
1098 (lc->attrs[i].mask & mask))
1104 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
1105 unsigned int line_idx)
1108 u64 mask = BIT_ULL(line_idx);
1110 for (i = 0; i < lc->num_attrs; i++) {
1111 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
1112 (lc->attrs[i].mask & mask))
1113 return lc->attrs[i].attr.debounce_period_us;
1118 static void edge_detector_stop(struct line *line)
1121 free_irq_label(free_irq(line->irq, line));
1126 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
1127 hte_ts_put(&line->hdesc);
1130 cancel_delayed_work_sync(&line->work);
1131 WRITE_ONCE(line->sw_debounced, 0);
1132 WRITE_ONCE(line->edflags, 0);
1133 line_set_debounce_period(line, 0);
1134 /* do not change line->level - see comment in debounced_value() */
1137 static int edge_detector_setup(struct line *line,
1138 struct gpio_v2_line_config *lc,
1139 unsigned int line_idx, u64 edflags)
1141 u32 debounce_period_us;
1142 unsigned long irqflags = 0;
1147 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
1148 if (eflags && !kfifo_initialized(&line->req->events)) {
1149 ret = kfifo_alloc(&line->req->events,
1150 line->req->event_buffer_size, GFP_KERNEL);
1154 if (gpio_v2_line_config_debounced(lc, line_idx)) {
1155 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
1156 ret = debounce_setup(line, debounce_period_us);
1159 line_set_debounce_period(line, debounce_period_us);
1162 /* detection disabled or sw debouncer will provide edge detection */
1163 if (!eflags || READ_ONCE(line->sw_debounced))
1166 if (IS_ENABLED(CONFIG_HTE) &&
1167 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1168 return hte_edge_setup(line, edflags);
1170 irq = gpiod_to_irq(line->desc);
1174 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
1175 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1176 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1177 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
1178 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1179 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1180 irqflags |= IRQF_ONESHOT;
1182 label = make_irq_label(line->req->label);
1184 return PTR_ERR(label);
1186 /* Request a thread to read the events */
1187 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
1188 irqflags, label, line);
1190 free_irq_label(label);
1198 static int edge_detector_update(struct line *line,
1199 struct gpio_v2_line_config *lc,
1200 unsigned int line_idx, u64 edflags)
1202 u64 active_edflags = READ_ONCE(line->edflags);
1203 unsigned int debounce_period_us =
1204 gpio_v2_line_config_debounce_period(lc, line_idx);
1206 if ((active_edflags == edflags) &&
1207 (READ_ONCE(line->debounce_period_us) == debounce_period_us))
1210 /* sw debounced and still will be...*/
1211 if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
1212 line_set_debounce_period(line, debounce_period_us);
1216 /* reconfiguring edge detection or sw debounce being disabled */
1217 if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
1218 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
1219 (!debounce_period_us && READ_ONCE(line->sw_debounced)))
1220 edge_detector_stop(line);
1222 return edge_detector_setup(line, lc, line_idx, edflags);
1225 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
1226 unsigned int line_idx)
1229 u64 mask = BIT_ULL(line_idx);
1231 for (i = 0; i < lc->num_attrs; i++) {
1232 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
1233 (lc->attrs[i].mask & mask))
1234 return lc->attrs[i].attr.flags;
1239 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
1240 unsigned int line_idx)
1243 u64 mask = BIT_ULL(line_idx);
1245 for (i = 0; i < lc->num_attrs; i++) {
1246 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
1247 (lc->attrs[i].mask & mask))
1248 return !!(lc->attrs[i].attr.values & mask);
1253 static int gpio_v2_line_flags_validate(u64 flags)
1255 /* Return an error if an unknown flag is set */
1256 if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
1259 if (!IS_ENABLED(CONFIG_HTE) &&
1260 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1264 * Do not allow both INPUT and OUTPUT flags to be set as they are
1267 if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
1268 (flags & GPIO_V2_LINE_FLAG_OUTPUT))
1271 /* Only allow one event clock source */
1272 if (IS_ENABLED(CONFIG_HTE) &&
1273 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
1274 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1277 /* Edge detection requires explicit input. */
1278 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
1279 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1283 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
1284 * request. If the hardware actually supports enabling both at the
1285 * same time the electrical result would be disastrous.
1287 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
1288 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
1291 /* Drive requires explicit output direction. */
1292 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
1293 !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
1296 /* Bias requires explicit direction. */
1297 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
1298 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
1301 /* Only one bias flag can be set. */
1302 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
1303 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
1304 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
1305 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
1306 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
1312 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
1313 unsigned int num_lines)
1319 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
1322 if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
1325 for (i = 0; i < num_lines; i++) {
1326 flags = gpio_v2_line_config_flags(lc, i);
1327 ret = gpio_v2_line_flags_validate(flags);
1331 /* debounce requires explicit input */
1332 if (gpio_v2_line_config_debounced(lc, i) &&
1333 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1339 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
1340 unsigned long *flagsp)
1342 assign_bit(FLAG_ACTIVE_LOW, flagsp,
1343 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
1345 if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
1346 set_bit(FLAG_IS_OUT, flagsp);
1347 else if (flags & GPIO_V2_LINE_FLAG_INPUT)
1348 clear_bit(FLAG_IS_OUT, flagsp);
1350 assign_bit(FLAG_EDGE_RISING, flagsp,
1351 flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
1352 assign_bit(FLAG_EDGE_FALLING, flagsp,
1353 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
1355 assign_bit(FLAG_OPEN_DRAIN, flagsp,
1356 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
1357 assign_bit(FLAG_OPEN_SOURCE, flagsp,
1358 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
1360 assign_bit(FLAG_PULL_UP, flagsp,
1361 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
1362 assign_bit(FLAG_PULL_DOWN, flagsp,
1363 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
1364 assign_bit(FLAG_BIAS_DISABLE, flagsp,
1365 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
1367 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp,
1368 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
1369 assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp,
1370 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
1373 static long linereq_get_values(struct linereq *lr, void __user *ip)
1375 struct gpio_v2_line_values lv;
1376 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1377 struct gpio_desc **descs;
1378 unsigned int i, didx, num_get;
1382 /* NOTE: It's ok to read values of output lines. */
1383 if (copy_from_user(&lv, ip, sizeof(lv)))
1387 * gpiod_get_array_value_complex() requires compacted desc and val
1388 * arrays, rather than the sparse ones in lv.
1389 * Calculation of num_get and construction of the desc array is
1390 * optimized to avoid allocation for the desc array for the common
1391 * num_get == 1 case.
1393 /* scan requested lines to calculate the subset to get */
1394 for (num_get = 0, i = 0; i < lr->num_lines; i++) {
1395 if (lv.mask & BIT_ULL(i)) {
1397 /* capture desc for the num_get == 1 case */
1398 descs = &lr->lines[i].desc;
1406 /* build compacted desc array */
1407 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
1410 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1411 if (lv.mask & BIT_ULL(i)) {
1412 descs[didx] = lr->lines[i].desc;
1417 ret = gpiod_get_array_value_complex(false, true, num_get,
1426 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1427 /* unpack compacted vals for the response */
1428 if (lv.mask & BIT_ULL(i)) {
1429 if (lr->lines[i].sw_debounced)
1430 val = debounced_value(&lr->lines[i]);
1432 val = test_bit(didx, vals);
1434 lv.bits |= BIT_ULL(i);
1439 if (copy_to_user(ip, &lv, sizeof(lv)))
1445 static long linereq_set_values(struct linereq *lr, void __user *ip)
1447 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1448 struct gpio_v2_line_values lv;
1449 struct gpio_desc **descs;
1450 unsigned int i, didx, num_set;
1453 if (copy_from_user(&lv, ip, sizeof(lv)))
1456 guard(mutex)(&lr->config_mutex);
1459 * gpiod_set_array_value_complex() requires compacted desc and val
1460 * arrays, rather than the sparse ones in lv.
1461 * Calculation of num_set and construction of the descs and vals arrays
1462 * is optimized to minimize scanning the lv->mask, and to avoid
1463 * allocation for the desc array for the common num_set == 1 case.
1465 bitmap_zero(vals, GPIO_V2_LINES_MAX);
1466 /* scan requested lines to determine the subset to be set */
1467 for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1468 if (lv.mask & BIT_ULL(i)) {
1469 /* setting inputs is not allowed */
1470 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
1472 /* add to compacted values */
1473 if (lv.bits & BIT_ULL(i))
1474 __set_bit(num_set, vals);
1476 /* capture desc for the num_set == 1 case */
1477 descs = &lr->lines[i].desc;
1484 /* build compacted desc array */
1485 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
1488 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1489 if (lv.mask & BIT_ULL(i)) {
1490 descs[didx] = lr->lines[i].desc;
1495 ret = gpiod_set_array_value_complex(false, true, num_set,
1503 static long linereq_set_config(struct linereq *lr, void __user *ip)
1505 struct gpio_v2_line_config lc;
1506 struct gpio_desc *desc;
1512 if (copy_from_user(&lc, ip, sizeof(lc)))
1515 ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1519 guard(mutex)(&lr->config_mutex);
1521 for (i = 0; i < lr->num_lines; i++) {
1522 line = &lr->lines[i];
1523 desc = lr->lines[i].desc;
1524 flags = gpio_v2_line_config_flags(&lc, i);
1525 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1526 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1528 * Lines have to be requested explicitly for input
1529 * or output, else the line will be treated "as is".
1531 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1532 int val = gpio_v2_line_config_output_value(&lc, i);
1534 edge_detector_stop(line);
1535 ret = gpiod_direction_output(desc, val);
1538 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1539 ret = gpiod_direction_input(desc);
1543 ret = edge_detector_update(line, &lc, i, edflags);
1548 WRITE_ONCE(line->edflags, edflags);
1550 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
1555 static long linereq_ioctl(struct file *file, unsigned int cmd,
1558 struct linereq *lr = file->private_data;
1559 void __user *ip = (void __user *)arg;
1561 guard(rwsem_read)(&lr->gdev->sem);
1563 if (!lr->gdev->chip)
1567 case GPIO_V2_LINE_GET_VALUES_IOCTL:
1568 return linereq_get_values(lr, ip);
1569 case GPIO_V2_LINE_SET_VALUES_IOCTL:
1570 return linereq_set_values(lr, ip);
1571 case GPIO_V2_LINE_SET_CONFIG_IOCTL:
1572 return linereq_set_config(lr, ip);
1578 #ifdef CONFIG_COMPAT
1579 static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1582 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1586 static __poll_t linereq_poll(struct file *file,
1587 struct poll_table_struct *wait)
1589 struct linereq *lr = file->private_data;
1590 __poll_t events = 0;
1592 guard(rwsem_read)(&lr->gdev->sem);
1594 if (!lr->gdev->chip)
1595 return EPOLLHUP | EPOLLERR;
1597 poll_wait(file, &lr->wait, wait);
1599 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1601 events = EPOLLIN | EPOLLRDNORM;
1606 static ssize_t linereq_read(struct file *file, char __user *buf,
1607 size_t count, loff_t *f_ps)
1609 struct linereq *lr = file->private_data;
1610 struct gpio_v2_line_event le;
1611 ssize_t bytes_read = 0;
1614 guard(rwsem_read)(&lr->gdev->sem);
1616 if (!lr->gdev->chip)
1619 if (count < sizeof(le))
1623 scoped_guard(spinlock, &lr->wait.lock) {
1624 if (kfifo_is_empty(&lr->events)) {
1628 if (file->f_flags & O_NONBLOCK)
1631 ret = wait_event_interruptible_locked(lr->wait,
1632 !kfifo_is_empty(&lr->events));
1637 ret = kfifo_out(&lr->events, &le, 1);
1641 * This should never happen - we were holding the
1642 * lock from the moment we learned the fifo is no
1643 * longer empty until now.
1649 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1651 bytes_read += sizeof(le);
1652 } while (count >= bytes_read + sizeof(le));
1657 static void linereq_free(struct linereq *lr)
1662 if (lr->device_unregistered_nb.notifier_call)
1663 blocking_notifier_chain_unregister(&lr->gdev->device_notifier,
1664 &lr->device_unregistered_nb);
1666 for (i = 0; i < lr->num_lines; i++) {
1667 line = &lr->lines[i];
1671 edge_detector_stop(line);
1672 if (line_has_supinfo(line))
1673 supinfo_erase(line);
1674 gpiod_free(line->desc);
1676 kfifo_free(&lr->events);
1678 gpio_device_put(lr->gdev);
1682 static int linereq_release(struct inode *inode, struct file *file)
1684 struct linereq *lr = file->private_data;
1690 #ifdef CONFIG_PROC_FS
1691 static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
1693 struct linereq *lr = file->private_data;
1694 struct device *dev = &lr->gdev->dev;
1697 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));
1699 for (i = 0; i < lr->num_lines; i++)
1700 seq_printf(out, "gpio-line:\t%d\n",
1701 gpio_chip_hwgpio(lr->lines[i].desc));
1705 static const struct file_operations line_fileops = {
1706 .release = linereq_release,
1707 .read = linereq_read,
1708 .poll = linereq_poll,
1709 .owner = THIS_MODULE,
1710 .llseek = noop_llseek,
1711 .unlocked_ioctl = linereq_ioctl,
1712 #ifdef CONFIG_COMPAT
1713 .compat_ioctl = linereq_ioctl_compat,
1715 #ifdef CONFIG_PROC_FS
1716 .show_fdinfo = linereq_show_fdinfo,
1720 static int linereq_create(struct gpio_device *gdev, void __user *ip)
1722 struct gpio_v2_line_request ulr;
1723 struct gpio_v2_line_config *lc;
1730 if (copy_from_user(&ulr, ip, sizeof(ulr)))
1733 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1736 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
1740 ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1744 lr = kvzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
1747 lr->num_lines = ulr.num_lines;
1749 lr->gdev = gpio_device_get(gdev);
1751 for (i = 0; i < ulr.num_lines; i++) {
1752 lr->lines[i].req = lr;
1753 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1754 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1757 if (ulr.consumer[0] != '\0') {
1758 /* label is only initialized if consumer is set */
1759 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1763 goto out_free_linereq;
1767 mutex_init(&lr->config_mutex);
1768 init_waitqueue_head(&lr->wait);
1769 lr->event_buffer_size = ulr.event_buffer_size;
1770 if (lr->event_buffer_size == 0)
1771 lr->event_buffer_size = ulr.num_lines * 16;
1772 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1773 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1775 atomic_set(&lr->seqno, 0);
1777 /* Request each GPIO */
1778 for (i = 0; i < ulr.num_lines; i++) {
1779 u32 offset = ulr.offsets[i];
1780 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
1783 ret = PTR_ERR(desc);
1784 goto out_free_linereq;
1787 ret = gpiod_request_user(desc, lr->label);
1789 goto out_free_linereq;
1791 lr->lines[i].desc = desc;
1792 flags = gpio_v2_line_config_flags(lc, i);
1793 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1795 ret = gpiod_set_transitory(desc, false);
1797 goto out_free_linereq;
1799 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1801 * Lines have to be requested explicitly for input
1802 * or output, else the line will be treated "as is".
1804 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1805 int val = gpio_v2_line_config_output_value(lc, i);
1807 ret = gpiod_direction_output(desc, val);
1809 goto out_free_linereq;
1810 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1811 ret = gpiod_direction_input(desc);
1813 goto out_free_linereq;
1815 ret = edge_detector_setup(&lr->lines[i], lc, i,
1818 goto out_free_linereq;
1821 lr->lines[i].edflags = edflags;
1823 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
1825 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1829 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify;
1830 ret = blocking_notifier_chain_register(&gdev->device_notifier,
1831 &lr->device_unregistered_nb);
1833 goto out_free_linereq;
1835 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1838 goto out_free_linereq;
1841 file = anon_inode_getfile("gpio-line", &line_fileops, lr,
1842 O_RDONLY | O_CLOEXEC);
1844 ret = PTR_ERR(file);
1845 goto out_put_unused_fd;
1849 if (copy_to_user(ip, &ulr, sizeof(ulr))) {
1851 * fput() will trigger the release() callback, so do not go onto
1852 * the regular error cleanup path here.
1859 fd_install(fd, file);
1861 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1873 #ifdef CONFIG_GPIO_CDEV_V1
1876 * GPIO line event management
1880 * struct lineevent_state - contains the state of a userspace event
1881 * @gdev: the GPIO device the event pertains to
1882 * @label: consumer label used to tag descriptors
1883 * @desc: the GPIO descriptor held by this event
1884 * @eflags: the event flags this line was requested with
1885 * @irq: the interrupt that trigger in response to events on this GPIO
1886 * @wait: wait queue that handles blocking reads of events
1887 * @device_unregistered_nb: notifier block for receiving gdev unregister events
1888 * @events: KFIFO for the GPIO events
1889 * @timestamp: cache for the timestamp storing it between hardirq
1890 * and IRQ thread, used to bring the timestamp close to the actual
1893 struct lineevent_state {
1894 struct gpio_device *gdev;
1896 struct gpio_desc *desc;
1899 wait_queue_head_t wait;
1900 struct notifier_block device_unregistered_nb;
1901 DECLARE_KFIFO(events, struct gpioevent_data, 16);
1905 #define GPIOEVENT_REQUEST_VALID_FLAGS \
1906 (GPIOEVENT_REQUEST_RISING_EDGE | \
1907 GPIOEVENT_REQUEST_FALLING_EDGE)
1909 static __poll_t lineevent_poll(struct file *file,
1910 struct poll_table_struct *wait)
1912 struct lineevent_state *le = file->private_data;
1913 __poll_t events = 0;
1915 guard(rwsem_read)(&le->gdev->sem);
1917 if (!le->gdev->chip)
1918 return EPOLLHUP | EPOLLERR;
1920 poll_wait(file, &le->wait, wait);
1922 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1923 events = EPOLLIN | EPOLLRDNORM;
1928 static int lineevent_unregistered_notify(struct notifier_block *nb,
1929 unsigned long action, void *data)
1931 struct lineevent_state *le = container_of(nb, struct lineevent_state,
1932 device_unregistered_nb);
1934 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR);
1939 struct compat_gpioeevent_data {
1940 compat_u64 timestamp;
1944 static ssize_t lineevent_read(struct file *file, char __user *buf,
1945 size_t count, loff_t *f_ps)
1947 struct lineevent_state *le = file->private_data;
1948 struct gpioevent_data ge;
1949 ssize_t bytes_read = 0;
1953 guard(rwsem_read)(&le->gdev->sem);
1955 if (!le->gdev->chip)
1959 * When compatible system call is being used the struct gpioevent_data,
1960 * in case of at least ia32, has different size due to the alignment
1961 * differences. Because we have first member 64 bits followed by one of
1962 * 32 bits there is no gap between them. The only difference is the
1963 * padding at the end of the data structure. Hence, we calculate the
1964 * actual sizeof() and pass this as an argument to copy_to_user() to
1965 * drop unneeded bytes from the output.
1967 if (compat_need_64bit_alignment_fixup())
1968 ge_size = sizeof(struct compat_gpioeevent_data);
1970 ge_size = sizeof(struct gpioevent_data);
1971 if (count < ge_size)
1975 scoped_guard(spinlock, &le->wait.lock) {
1976 if (kfifo_is_empty(&le->events)) {
1980 if (file->f_flags & O_NONBLOCK)
1983 ret = wait_event_interruptible_locked(le->wait,
1984 !kfifo_is_empty(&le->events));
1989 ret = kfifo_out(&le->events, &ge, 1);
1993 * This should never happen - we were holding the lock
1994 * from the moment we learned the fifo is no longer
2001 if (copy_to_user(buf + bytes_read, &ge, ge_size))
2003 bytes_read += ge_size;
2004 } while (count >= bytes_read + ge_size);
2009 static void lineevent_free(struct lineevent_state *le)
2011 if (le->device_unregistered_nb.notifier_call)
2012 blocking_notifier_chain_unregister(&le->gdev->device_notifier,
2013 &le->device_unregistered_nb);
2015 free_irq_label(free_irq(le->irq, le));
2017 gpiod_free(le->desc);
2019 gpio_device_put(le->gdev);
2023 static int lineevent_release(struct inode *inode, struct file *file)
2025 lineevent_free(file->private_data);
2029 static long lineevent_ioctl(struct file *file, unsigned int cmd,
2032 struct lineevent_state *le = file->private_data;
2033 void __user *ip = (void __user *)arg;
2034 struct gpiohandle_data ghd;
2036 guard(rwsem_read)(&le->gdev->sem);
2038 if (!le->gdev->chip)
2042 * We can get the value for an event line but not set it,
2043 * because it is input by definition.
2045 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
2048 memset(&ghd, 0, sizeof(ghd));
2050 val = gpiod_get_value_cansleep(le->desc);
2053 ghd.values[0] = val;
2055 if (copy_to_user(ip, &ghd, sizeof(ghd)))
2063 #ifdef CONFIG_COMPAT
2064 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
2067 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2071 static const struct file_operations lineevent_fileops = {
2072 .release = lineevent_release,
2073 .read = lineevent_read,
2074 .poll = lineevent_poll,
2075 .owner = THIS_MODULE,
2076 .llseek = noop_llseek,
2077 .unlocked_ioctl = lineevent_ioctl,
2078 #ifdef CONFIG_COMPAT
2079 .compat_ioctl = lineevent_ioctl_compat,
2083 static irqreturn_t lineevent_irq_thread(int irq, void *p)
2085 struct lineevent_state *le = p;
2086 struct gpioevent_data ge;
2089 /* Do not leak kernel stack to userspace */
2090 memset(&ge, 0, sizeof(ge));
2093 * We may be running from a nested threaded interrupt in which case
2094 * we didn't get the timestamp from lineevent_irq_handler().
2097 ge.timestamp = ktime_get_ns();
2099 ge.timestamp = le->timestamp;
2101 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
2102 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2103 int level = gpiod_get_value_cansleep(le->desc);
2106 /* Emit low-to-high event */
2107 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2109 /* Emit high-to-low event */
2110 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2111 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
2112 /* Emit low-to-high event */
2113 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2114 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2115 /* Emit high-to-low event */
2116 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2121 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
2124 wake_up_poll(&le->wait, EPOLLIN);
2126 pr_debug_ratelimited("event FIFO is full - event dropped\n");
2131 static irqreturn_t lineevent_irq_handler(int irq, void *p)
2133 struct lineevent_state *le = p;
2136 * Just store the timestamp in hardirq context so we get it as
2137 * close in time as possible to the actual event.
2139 le->timestamp = ktime_get_ns();
2141 return IRQ_WAKE_THREAD;
2144 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
2146 struct gpioevent_request eventreq;
2147 struct lineevent_state *le;
2148 struct gpio_desc *desc;
2155 int irq, irqflags = 0;
2158 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
2161 offset = eventreq.lineoffset;
2162 lflags = eventreq.handleflags;
2163 eflags = eventreq.eventflags;
2165 desc = gpiochip_get_desc(gdev->chip, offset);
2167 return PTR_ERR(desc);
2169 /* Return an error if a unknown flag is set */
2170 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
2171 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
2174 /* This is just wrong: we don't look for events on output lines */
2175 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
2176 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
2177 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
2180 /* Only one bias flag can be set. */
2181 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
2182 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
2183 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
2184 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
2185 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
2188 le = kzalloc(sizeof(*le), GFP_KERNEL);
2191 le->gdev = gpio_device_get(gdev);
2193 if (eventreq.consumer_label[0] != '\0') {
2194 /* label is only initialized if consumer_label is set */
2195 le->label = kstrndup(eventreq.consumer_label,
2196 sizeof(eventreq.consumer_label) - 1,
2204 ret = gpiod_request_user(desc, le->label);
2208 le->eflags = eflags;
2210 linehandle_flags_to_desc_flags(lflags, &desc->flags);
2212 ret = gpiod_direction_input(desc);
2216 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
2218 irq = gpiod_to_irq(desc);
2224 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
2225 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2226 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
2227 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
2228 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2229 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
2230 irqflags |= IRQF_ONESHOT;
2232 INIT_KFIFO(le->events);
2233 init_waitqueue_head(&le->wait);
2235 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify;
2236 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2237 &le->device_unregistered_nb);
2241 label = make_irq_label(le->label);
2242 if (IS_ERR(label)) {
2243 ret = PTR_ERR(label);
2247 /* Request a thread to read the events */
2248 ret = request_threaded_irq(irq,
2249 lineevent_irq_handler,
2250 lineevent_irq_thread,
2255 free_irq_label(label);
2261 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
2267 file = anon_inode_getfile("gpio-event",
2270 O_RDONLY | O_CLOEXEC);
2272 ret = PTR_ERR(file);
2273 goto out_put_unused_fd;
2277 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
2279 * fput() will trigger the release() callback, so do not go onto
2280 * the regular error cleanup path here.
2287 fd_install(fd, file);
2298 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
2299 struct gpioline_info *info_v1)
2301 u64 flagsv2 = info_v2->flags;
2303 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
2304 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
2305 info_v1->line_offset = info_v2->offset;
2308 if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
2309 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
2311 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
2312 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
2314 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
2315 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
2317 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
2318 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
2319 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
2320 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
2322 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
2323 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
2324 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
2325 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
2326 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
2327 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
2330 static void gpio_v2_line_info_changed_to_v1(
2331 struct gpio_v2_line_info_changed *lic_v2,
2332 struct gpioline_info_changed *lic_v1)
2334 memset(lic_v1, 0, sizeof(*lic_v1));
2335 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
2336 lic_v1->timestamp = lic_v2->timestamp_ns;
2337 lic_v1->event_type = lic_v2->event_type;
2340 #endif /* CONFIG_GPIO_CDEV_V1 */
2342 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
2343 struct gpio_v2_line_info *info)
2345 struct gpio_chip *gc = desc->gdev->chip;
2346 unsigned long dflags;
2348 memset(info, 0, sizeof(*info));
2349 info->offset = gpio_chip_hwgpio(desc);
2351 scoped_guard(spinlock_irqsave, &gpio_lock) {
2353 strscpy(info->name, desc->name, sizeof(info->name));
2356 strscpy(info->consumer, desc->label,
2357 sizeof(info->consumer));
2359 dflags = READ_ONCE(desc->flags);
2363 * Userspace only need know that the kernel is using this GPIO so it
2365 * The calculation of the used flag is slightly racy, as it may read
2366 * desc, gc and pinctrl state without a lock covering all three at
2367 * once. Worst case if the line is in transition and the calculation
2368 * is inconsistent then it looks to the user like they performed the
2369 * read on the other side of the transition - but that can always
2371 * The definitive test that a line is available to userspace is to
2374 if (test_bit(FLAG_REQUESTED, &dflags) ||
2375 test_bit(FLAG_IS_HOGGED, &dflags) ||
2376 test_bit(FLAG_USED_AS_IRQ, &dflags) ||
2377 test_bit(FLAG_EXPORT, &dflags) ||
2378 test_bit(FLAG_SYSFS, &dflags) ||
2379 !gpiochip_line_is_valid(gc, info->offset) ||
2380 !pinctrl_gpio_can_use_line(gc, info->offset))
2381 info->flags |= GPIO_V2_LINE_FLAG_USED;
2383 if (test_bit(FLAG_IS_OUT, &dflags))
2384 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
2386 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
2388 if (test_bit(FLAG_ACTIVE_LOW, &dflags))
2389 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
2391 if (test_bit(FLAG_OPEN_DRAIN, &dflags))
2392 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
2393 if (test_bit(FLAG_OPEN_SOURCE, &dflags))
2394 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
2396 if (test_bit(FLAG_BIAS_DISABLE, &dflags))
2397 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
2398 if (test_bit(FLAG_PULL_DOWN, &dflags))
2399 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
2400 if (test_bit(FLAG_PULL_UP, &dflags))
2401 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
2403 if (test_bit(FLAG_EDGE_RISING, &dflags))
2404 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
2405 if (test_bit(FLAG_EDGE_FALLING, &dflags))
2406 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
2408 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &dflags))
2409 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
2410 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags))
2411 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
2414 struct gpio_chardev_data {
2415 struct gpio_device *gdev;
2416 wait_queue_head_t wait;
2417 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
2418 struct notifier_block lineinfo_changed_nb;
2419 struct notifier_block device_unregistered_nb;
2420 unsigned long *watched_lines;
2421 #ifdef CONFIG_GPIO_CDEV_V1
2422 atomic_t watch_abi_version;
2426 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
2428 struct gpio_device *gdev = cdev->gdev;
2429 struct gpiochip_info chipinfo;
2431 memset(&chipinfo, 0, sizeof(chipinfo));
2433 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
2434 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
2435 chipinfo.lines = gdev->ngpio;
2436 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
2441 #ifdef CONFIG_GPIO_CDEV_V1
2443 * returns 0 if the versions match, else the previously selected ABI version
2445 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
2446 unsigned int version)
2448 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
2450 if (abiv == version)
2456 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
2459 struct gpio_desc *desc;
2460 struct gpioline_info lineinfo;
2461 struct gpio_v2_line_info lineinfo_v2;
2463 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2466 /* this doubles as a range check on line_offset */
2467 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
2469 return PTR_ERR(desc);
2472 if (lineinfo_ensure_abi_version(cdev, 1))
2475 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2479 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2480 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2482 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2484 clear_bit(lineinfo.line_offset, cdev->watched_lines);
2492 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
2495 struct gpio_desc *desc;
2496 struct gpio_v2_line_info lineinfo;
2498 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2501 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
2504 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
2506 return PTR_ERR(desc);
2509 #ifdef CONFIG_GPIO_CDEV_V1
2510 if (lineinfo_ensure_abi_version(cdev, 2))
2513 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2516 gpio_desc_to_lineinfo(desc, &lineinfo);
2517 supinfo_to_lineinfo(desc, &lineinfo);
2519 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2521 clear_bit(lineinfo.offset, cdev->watched_lines);
2528 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
2532 if (copy_from_user(&offset, ip, sizeof(offset)))
2535 if (offset >= cdev->gdev->ngpio)
2538 if (!test_and_clear_bit(offset, cdev->watched_lines))
2545 * gpio_ioctl() - ioctl handler for the GPIO chardev
2547 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2549 struct gpio_chardev_data *cdev = file->private_data;
2550 struct gpio_device *gdev = cdev->gdev;
2551 void __user *ip = (void __user *)arg;
2553 guard(rwsem_read)(&gdev->sem);
2555 /* We fail any subsequent ioctl():s when the chip is gone */
2559 /* Fill in the struct and pass to userspace */
2561 case GPIO_GET_CHIPINFO_IOCTL:
2562 return chipinfo_get(cdev, ip);
2563 #ifdef CONFIG_GPIO_CDEV_V1
2564 case GPIO_GET_LINEHANDLE_IOCTL:
2565 return linehandle_create(gdev, ip);
2566 case GPIO_GET_LINEEVENT_IOCTL:
2567 return lineevent_create(gdev, ip);
2568 case GPIO_GET_LINEINFO_IOCTL:
2569 return lineinfo_get_v1(cdev, ip, false);
2570 case GPIO_GET_LINEINFO_WATCH_IOCTL:
2571 return lineinfo_get_v1(cdev, ip, true);
2572 #endif /* CONFIG_GPIO_CDEV_V1 */
2573 case GPIO_V2_GET_LINEINFO_IOCTL:
2574 return lineinfo_get(cdev, ip, false);
2575 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
2576 return lineinfo_get(cdev, ip, true);
2577 case GPIO_V2_GET_LINE_IOCTL:
2578 return linereq_create(gdev, ip);
2579 case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
2580 return lineinfo_unwatch(cdev, ip);
2586 #ifdef CONFIG_COMPAT
2587 static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2590 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2594 static int lineinfo_changed_notify(struct notifier_block *nb,
2595 unsigned long action, void *data)
2597 struct gpio_chardev_data *cdev =
2598 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2599 struct gpio_v2_line_info_changed chg;
2600 struct gpio_desc *desc = data;
2603 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
2606 memset(&chg, 0, sizeof(chg));
2607 chg.event_type = action;
2608 chg.timestamp_ns = ktime_get_ns();
2609 gpio_desc_to_lineinfo(desc, &chg.info);
2610 supinfo_to_lineinfo(desc, &chg.info);
2612 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
2614 wake_up_poll(&cdev->wait, EPOLLIN);
2616 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2621 static int gpio_device_unregistered_notify(struct notifier_block *nb,
2622 unsigned long action, void *data)
2624 struct gpio_chardev_data *cdev = container_of(nb,
2625 struct gpio_chardev_data,
2626 device_unregistered_nb);
2628 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR);
2633 static __poll_t lineinfo_watch_poll(struct file *file,
2634 struct poll_table_struct *pollt)
2636 struct gpio_chardev_data *cdev = file->private_data;
2637 __poll_t events = 0;
2639 guard(rwsem_read)(&cdev->gdev->sem);
2641 if (!cdev->gdev->chip)
2642 return EPOLLHUP | EPOLLERR;
2644 poll_wait(file, &cdev->wait, pollt);
2646 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2648 events = EPOLLIN | EPOLLRDNORM;
2653 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2654 size_t count, loff_t *off)
2656 struct gpio_chardev_data *cdev = file->private_data;
2657 struct gpio_v2_line_info_changed event;
2658 ssize_t bytes_read = 0;
2662 guard(rwsem_read)(&cdev->gdev->sem);
2664 if (!cdev->gdev->chip)
2667 #ifndef CONFIG_GPIO_CDEV_V1
2668 event_size = sizeof(struct gpio_v2_line_info_changed);
2669 if (count < event_size)
2674 scoped_guard(spinlock, &cdev->wait.lock) {
2675 if (kfifo_is_empty(&cdev->events)) {
2679 if (file->f_flags & O_NONBLOCK)
2682 ret = wait_event_interruptible_locked(cdev->wait,
2683 !kfifo_is_empty(&cdev->events));
2687 #ifdef CONFIG_GPIO_CDEV_V1
2688 /* must be after kfifo check so watch_abi_version is set */
2689 if (atomic_read(&cdev->watch_abi_version) == 2)
2690 event_size = sizeof(struct gpio_v2_line_info_changed);
2692 event_size = sizeof(struct gpioline_info_changed);
2693 if (count < event_size)
2696 ret = kfifo_out(&cdev->events, &event, 1);
2701 /* We should never get here. See lineevent_read(). */
2704 #ifdef CONFIG_GPIO_CDEV_V1
2705 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2706 if (copy_to_user(buf + bytes_read, &event, event_size))
2709 struct gpioline_info_changed event_v1;
2711 gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2712 if (copy_to_user(buf + bytes_read, &event_v1,
2717 if (copy_to_user(buf + bytes_read, &event, event_size))
2720 bytes_read += event_size;
2721 } while (count >= bytes_read + sizeof(event));
2727 * gpio_chrdev_open() - open the chardev for ioctl operations
2728 * @inode: inode for this chardev
2729 * @file: file struct for storing private data
2730 * Returns 0 on success
2732 static int gpio_chrdev_open(struct inode *inode, struct file *file)
2734 struct gpio_device *gdev = container_of(inode->i_cdev,
2735 struct gpio_device, chrdev);
2736 struct gpio_chardev_data *cdev;
2739 guard(rwsem_read)(&gdev->sem);
2741 /* Fail on open if the backing gpiochip is gone */
2745 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2749 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
2750 if (!cdev->watched_lines)
2753 init_waitqueue_head(&cdev->wait);
2754 INIT_KFIFO(cdev->events);
2755 cdev->gdev = gpio_device_get(gdev);
2757 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2758 ret = blocking_notifier_chain_register(&gdev->line_state_notifier,
2759 &cdev->lineinfo_changed_nb);
2761 goto out_free_bitmap;
2763 cdev->device_unregistered_nb.notifier_call =
2764 gpio_device_unregistered_notify;
2765 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2766 &cdev->device_unregistered_nb);
2768 goto out_unregister_line_notifier;
2770 file->private_data = cdev;
2772 ret = nonseekable_open(inode, file);
2774 goto out_unregister_device_notifier;
2778 out_unregister_device_notifier:
2779 blocking_notifier_chain_unregister(&gdev->device_notifier,
2780 &cdev->device_unregistered_nb);
2781 out_unregister_line_notifier:
2782 blocking_notifier_chain_unregister(&gdev->line_state_notifier,
2783 &cdev->lineinfo_changed_nb);
2785 gpio_device_put(gdev);
2786 bitmap_free(cdev->watched_lines);
2793 * gpio_chrdev_release() - close chardev after ioctl operations
2794 * @inode: inode for this chardev
2795 * @file: file struct for storing private data
2796 * Returns 0 on success
2798 static int gpio_chrdev_release(struct inode *inode, struct file *file)
2800 struct gpio_chardev_data *cdev = file->private_data;
2801 struct gpio_device *gdev = cdev->gdev;
2803 bitmap_free(cdev->watched_lines);
2804 blocking_notifier_chain_unregister(&gdev->device_notifier,
2805 &cdev->device_unregistered_nb);
2806 blocking_notifier_chain_unregister(&gdev->line_state_notifier,
2807 &cdev->lineinfo_changed_nb);
2808 gpio_device_put(gdev);
2814 static const struct file_operations gpio_fileops = {
2815 .release = gpio_chrdev_release,
2816 .open = gpio_chrdev_open,
2817 .poll = lineinfo_watch_poll,
2818 .read = lineinfo_watch_read,
2819 .owner = THIS_MODULE,
2820 .llseek = no_llseek,
2821 .unlocked_ioctl = gpio_ioctl,
2822 #ifdef CONFIG_COMPAT
2823 .compat_ioctl = gpio_ioctl_compat,
2827 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
2831 cdev_init(&gdev->chrdev, &gpio_fileops);
2832 gdev->chrdev.owner = THIS_MODULE;
2833 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2835 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2839 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
2840 MAJOR(devt), gdev->id);
2845 void gpiolib_cdev_unregister(struct gpio_device *gdev)
2847 cdev_device_del(&gdev->chrdev, &gdev->dev);
2848 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL);