gpio: cdev: go back to storing debounce period in the GPIO descriptor (81625f36) · Commits · git / linux-nf

drivers/gpio/gpiolib-cdev.c

+22 −141

Original line number	Diff line number	Diff line
		@@ -23,7 +23,6 @@
		#include <linux/overflow.h>
		#include <linux/pinctrl/consumer.h>
		#include <linux/poll.h>
		#include <linux/rbtree.h>
		#include <linux/seq_file.h>
		#include <linux/spinlock.h>
		#include <linux/timekeeping.h>
		@@ -421,7 +420,6 @@ static int linehandle_create(struct gpio_device gdev, void __user ip)

		/**
		* struct line - contains the state of a requested line
		* @node: to store the object in supinfo_tree if supplemental
		* @desc: the GPIO descriptor for this line.
		* @req: the corresponding line request
		* @irq: the interrupt triggered in response to events on this GPIO
		@@ -434,7 +432,6 @@ static int linehandle_create(struct gpio_device gdev, void __user ip)
		* @line_seqno: the seqno for the current edge event in the sequence of
		* events for this line.
		* @work: the worker that implements software debouncing
		* @debounce_period_us: the debounce period in microseconds
		* @sw_debounced: flag indicating if the software debouncer is active
		* @level: the current debounced physical level of the line
		* @hdesc: the Hardware Timestamp Engine (HTE) descriptor
		@@ -443,7 +440,6 @@ static int linehandle_create(struct gpio_device gdev, void __user ip)
		* @last_seqno: the last sequence number before debounce period expires
		*/
		struct line {
		struct rb_node node;
		struct gpio_desc *desc;
		/*
		* -- edge detector specific fields --
		@@ -477,15 +473,6 @@ struct line {
		* -- debouncer specific fields --
		*/
		struct delayed_work work;
		/*
		* debounce_period_us is accessed by debounce_irq_handler() and
		* process_hw_ts() which are disabled when modified by
		* debounce_setup(), edge_detector_setup() or edge_detector_stop()
		* or can live with a stale version when updated by
		* edge_detector_update().
		* The modifying functions are themselves mutually exclusive.
		*/
		unsigned int debounce_period_us;
		/*
		* sw_debounce is accessed by linereq_set_config(), which is the
		* only setter, and linereq_get_values(), which can live with a
		@@ -518,17 +505,6 @@ struct line {
		#endif /* CONFIG_HTE */
		};

		/*
		* a rbtree of the struct lines containing supplemental info.
		* Used to populate gpio_v2_line_info with cdev specific fields not contained
		* in the struct gpio_desc.
		* A line is determined to contain supplemental information by
		* line_has_supinfo().
		*/
		static struct rb_root supinfo_tree = RB_ROOT;
		/* covers supinfo_tree */
		static DEFINE_SPINLOCK(supinfo_lock);

		/**
		* struct linereq - contains the state of a userspace line request
		* @gdev: the GPIO device the line request pertains to
		@@ -542,8 +518,7 @@ static DEFINE_SPINLOCK(supinfo_lock);
		* this line request. Note that this is not used when @num_lines is 1, as
		* the line_seqno is then the same and is cheaper to calculate.
		* @config_mutex: mutex for serializing ioctl() calls to ensure consistency
		* of configuration, particularly multi-step accesses to desc flags and
		* changes to supinfo status.
		* of configuration, particularly multi-step accesses to desc flags.
		* @lines: the lines held by this line request, with @num_lines elements.
		*/
		struct linereq {
		@@ -559,103 +534,6 @@ struct linereq {
		struct line lines[] __counted_by(num_lines);
		};

		static void supinfo_insert(struct line *line)
		{
		struct rb_node *new = &(supinfo_tree.rb_node), parent = NULL;
		struct line *entry;

		guard(spinlock)(&supinfo_lock);

		while (*new) {
		entry = container_of(*new, struct line, node);

		parent = *new;
		if (line->desc < entry->desc) {
		new = &((*new)->rb_left);
		} else if (line->desc > entry->desc) {
		new = &((*new)->rb_right);
		} else {
		/* this should never happen */
		WARN(1, "duplicate line inserted");
		return;
		}
		}

		rb_link_node(&line->node, parent, new);
		rb_insert_color(&line->node, &supinfo_tree);
		}

		static void supinfo_erase(struct line *line)
		{
		guard(spinlock)(&supinfo_lock);

		rb_erase(&line->node, &supinfo_tree);
		}

		static struct line supinfo_find(struct gpio_desc desc)
		{
		struct rb_node *node = supinfo_tree.rb_node;
		struct line *line;

		while (node) {
		line = container_of(node, struct line, node);
		if (desc < line->desc)
		node = node->rb_left;
		else if (desc > line->desc)
		node = node->rb_right;
		else
		return line;
		}
		return NULL;
		}

		static void supinfo_to_lineinfo(struct gpio_desc *desc,
		struct gpio_v2_line_info *info)
		{
		struct gpio_v2_line_attribute *attr;
		struct line *line;

		guard(spinlock)(&supinfo_lock);

		line = supinfo_find(desc);
		if (!line)
		return;

		attr = &info->attrs[info->num_attrs];
		attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
		attr->debounce_period_us = READ_ONCE(line->debounce_period_us);
		info->num_attrs++;
		}

		static inline bool line_has_supinfo(struct line *line)
		{
		return READ_ONCE(line->debounce_period_us);
		}

		/*
		* Checks line_has_supinfo() before and after the change to avoid unnecessary
		* supinfo_tree access.
		* Called indirectly by linereq_create() or linereq_set_config() so line
		* is already protected from concurrent changes.
		*/
		static void line_set_debounce_period(struct line *line,
		unsigned int debounce_period_us)
		{
		bool was_suppl = line_has_supinfo(line);

		WRITE_ONCE(line->debounce_period_us, debounce_period_us);

		/* if supinfo status is unchanged then we're done */
		if (line_has_supinfo(line) == was_suppl)
		return;

		/* supinfo status has changed, so update the tree */
		if (was_suppl)
		supinfo_erase(line);
		else
		supinfo_insert(line);
		}

		#define GPIO_V2_LINE_BIAS_FLAGS \
		(GPIO_V2_LINE_FLAG_BIAS_PULL_UP \| \
		GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN \| \
		@@ -823,7 +701,7 @@ static enum hte_return process_hw_ts(struct hte_ts_data ts, void p)
		line->total_discard_seq++;
		line->last_seqno = ts->seq;
		mod_delayed_work(system_wq, &line->work,
		usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
		usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
		} else {
		if (unlikely(ts->seq < line->line_seqno))
		return HTE_CB_HANDLED;
		@@ -964,7 +842,7 @@ static irqreturn_t debounce_irq_handler(int irq, void *p)
		struct line *line = p;

		mod_delayed_work(system_wq, &line->work,
		usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
		usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));

		return IRQ_HANDLED;
		}
		@@ -1047,7 +925,7 @@ static int debounce_setup(struct line *line, unsigned int debounce_period_us)
		/* try hardware */
		ret = gpiod_set_debounce(line->desc, debounce_period_us);
		if (!ret) {
		line_set_debounce_period(line, debounce_period_us);
		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
		return ret;
		}
		if (ret != -ENOTSUPP)
		@@ -1132,7 +1010,8 @@ static void edge_detector_stop(struct line *line)
		cancel_delayed_work_sync(&line->work);
		WRITE_ONCE(line->sw_debounced, 0);
		WRITE_ONCE(line->edflags, 0);
		line_set_debounce_period(line, 0);
		if (line->desc)
		WRITE_ONCE(line->desc->debounce_period_us, 0);
		/* do not change line->level - see comment in debounced_value() */
		}

		@@ -1165,7 +1044,7 @@ static int edge_detector_setup(struct line *line,
		ret = debounce_setup(line, debounce_period_us);
		if (ret)
		return ret;
		line_set_debounce_period(line, debounce_period_us);
		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
		}

		/* detection disabled or sw debouncer will provide edge detection */
		@@ -1213,12 +1092,12 @@ static int edge_detector_update(struct line *line,
		gpio_v2_line_config_debounce_period(lc, line_idx);

		if ((active_edflags == edflags) &&
		(READ_ONCE(line->debounce_period_us) == debounce_period_us))
		(READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
		return 0;

		/* sw debounced and still will be...*/
		if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
		line_set_debounce_period(line, debounce_period_us);
		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
		/*
		* ensure event fifo is initialised if edge detection
		* is now enabled.
		@@ -1677,7 +1556,6 @@ static ssize_t linereq_read(struct file file, char __user buf,

		static void linereq_free(struct linereq *lr)
		{
		struct line *line;
		unsigned int i;

		if (lr->device_unregistered_nb.notifier_call)
		@@ -1685,14 +1563,10 @@ static void linereq_free(struct linereq *lr)
		&lr->device_unregistered_nb);

		for (i = 0; i < lr->num_lines; i++) {
		line = &lr->lines[i];
		if (!line->desc)
		continue;

		edge_detector_stop(line);
		if (line_has_supinfo(line))
		supinfo_erase(line);
		gpiod_free(line->desc);
		if (lr->lines[i].desc) {
		edge_detector_stop(&lr->lines[i]);
		gpiod_free(lr->lines[i].desc);
		}
		}
		kfifo_free(&lr->events);
		kfree(lr->label);
		@@ -2363,6 +2237,7 @@ static void gpio_v2_line_info_changed_to_v1(
		static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
		struct gpio_v2_line_info *info)
		{
		u32 debounce_period_us;
		unsigned long dflags;
		const char *label;

		@@ -2435,6 +2310,14 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
		info->flags \|= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
		else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags))
		info->flags \|= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;

		debounce_period_us = READ_ONCE(desc->debounce_period_us);
		if (debounce_period_us) {
		info->attrs[info->num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
		info->attrs[info->num_attrs].debounce_period_us =
		debounce_period_us;
		info->num_attrs++;
		}
		}

		struct gpio_chardev_data {
		@@ -2540,7 +2423,6 @@ static int lineinfo_get(struct gpio_chardev_data cdev, void __user ip,
		return -EBUSY;
		}
		gpio_desc_to_lineinfo(desc, &lineinfo);
		supinfo_to_lineinfo(desc, &lineinfo);

		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
		if (watch)
		@@ -2633,7 +2515,6 @@ static int lineinfo_changed_notify(struct notifier_block *nb,
		chg.event_type = action;
		chg.timestamp_ns = ktime_get_ns();
		gpio_desc_to_lineinfo(desc, &chg.info);
		supinfo_to_lineinfo(desc, &chg.info);

		ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
		if (ret)

drivers/gpio/gpiolib.c

+16 −2

Original line number	Diff line number	Diff line
		@@ -2432,7 +2432,9 @@ static void gpiod_free_commit(struct gpio_desc *desc)
		#endif
		desc_set_label(desc, NULL);
		WRITE_ONCE(desc->flags, flags);

		#ifdef CONFIG_GPIO_CDEV
		WRITE_ONCE(desc->debounce_period_us, 0);
		#endif
		gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_RELEASED);
		}
		}
		@@ -2564,6 +2566,8 @@ EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);

		static int gpio_do_set_config(struct gpio_desc *desc, unsigned long config)
		{
		int ret;

		CLASS(gpio_chip_guard, guard)(desc);
		if (!guard.gc)
		return -ENODEV;
		@@ -2571,7 +2575,17 @@ static int gpio_do_set_config(struct gpio_desc *desc, unsigned long config)
		if (!guard.gc->set_config)
		return -ENOTSUPP;

		return guard.gc->set_config(guard.gc, gpio_chip_hwgpio(desc), config);
		ret = guard.gc->set_config(guard.gc, gpio_chip_hwgpio(desc), config);
		#ifdef CONFIG_GPIO_CDEV
		/*
		* Special case - if we're setting debounce period, we need to store
		* it in the descriptor in case user-space wants to know it.
		*/
		if (!ret && pinconf_to_config_param(config) == PIN_CONFIG_INPUT_DEBOUNCE)
		WRITE_ONCE(desc->debounce_period_us,
		pinconf_to_config_argument(config));
		#endif
		return ret;
		}

		static int gpio_set_config_with_argument(struct gpio_desc *desc,

drivers/gpio/gpiolib.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -165,6 +165,7 @@ struct gpio_desc_label {
		* @label: Name of the consumer
		* @name: Line name
		* @hog: Pointer to the device node that hogs this line (if any)
		* @debounce_period_us: Debounce period in microseconds
		*
		* These are obtained using gpiod_get() and are preferable to the old
		* integer-based handles.
		@@ -202,6 +203,10 @@ struct gpio_desc {
		#ifdef CONFIG_OF_DYNAMIC
		struct device_node *hog;
		#endif
		#ifdef CONFIG_GPIO_CDEV
		/* debounce period in microseconds */
		unsigned int debounce_period_us;
		#endif
		};

		#define gpiod_not_found(desc) (IS_ERR(desc) && PTR_ERR(desc) == -ENOENT)