gpiolib: cdev: relocate debounce_period_us from struct gpio_desc (9344e34e) · Commits · git / linux-net

drivers/gpio/gpiolib-cdev.c

+142 −23

Original line number	Diff line number	Diff line
		@@ -5,6 +5,7 @@
		#include <linux/bitmap.h>
		#include <linux/build_bug.h>
		#include <linux/cdev.h>
		#include <linux/cleanup.h>
		#include <linux/compat.h>
		#include <linux/compiler.h>
		#include <linux/device.h>
		@@ -21,6 +22,7 @@
		#include <linux/mutex.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>
		@@ -461,6 +463,7 @@ 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
		@@ -473,6 +476,7 @@ 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
		@@ -481,6 +485,7 @@ 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 --
		@@ -514,6 +519,15 @@ 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
		@@ -546,6 +560,17 @@ 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
		@@ -559,7 +584,8 @@ struct line {
		* 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.
		* of configuration, particularly multi-step accesses to desc flags and
		* changes to supinfo status.
		* @lines: the lines held by this line request, with @num_lines elements.
		*/
		struct linereq {
		@@ -575,6 +601,103 @@ 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 \| \
		@@ -723,7 +846,7 @@ 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->desc->debounce_period_us)));
		usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
		} else {
		if (unlikely(ts->seq < line->line_seqno))
		return HTE_CB_HANDLED;
		@@ -864,7 +987,7 @@ 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->desc->debounce_period_us)));
		usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));

		return IRQ_HANDLED;
		}
		@@ -946,7 +1069,7 @@ 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) {
		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
		line_set_debounce_period(line, debounce_period_us);
		return ret;
		}
		if (ret != -ENOTSUPP)
		@@ -1025,8 +1148,7 @@ 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);
		if (line->desc)
		WRITE_ONCE(line->desc->debounce_period_us, 0);
		line_set_debounce_period(line, 0);
		/* do not change line->level - see comment in debounced_value() */
		}

		@@ -1051,7 +1173,7 @@ static int edge_detector_setup(struct line *line,
		ret = debounce_setup(line, debounce_period_us);
		if (ret)
		return ret;
		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
		line_set_debounce_period(line, debounce_period_us);
		}

		/* detection disabled or sw debouncer will provide edge detection */
		@@ -1093,12 +1215,12 @@ static int edge_detector_update(struct line *line,
		gpio_v2_line_config_debounce_period(lc, line_idx);

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

		/* sw debounced and still will be...*/
		if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
		line_set_debounce_period(line, debounce_period_us);
		return 0;
		}

		@@ -1573,6 +1695,7 @@ 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)
		@@ -1580,10 +1703,14 @@ static void linereq_free(struct linereq *lr)
		&lr->device_unregistered_nb);

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

		edge_detector_stop(line);
		if (line_has_supinfo(line))
		supinfo_erase(line);
		gpiod_free(line->desc);
		}
		kfifo_free(&lr->events);
		kfree(lr->label);
		@@ -2274,8 +2401,6 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
		struct gpio_chip *gc = desc->gdev->chip;
		bool ok_for_pinctrl;
		unsigned long flags;
		u32 debounce_period_us;
		unsigned int num_attrs = 0;

		memset(info, 0, sizeof(*info));
		info->offset = gpio_chip_hwgpio(desc);
		@@ -2341,14 +2466,6 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
		else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags))
		info->flags \|= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;

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

		spin_unlock_irqrestore(&gpio_lock, flags);
		}

		@@ -2455,6 +2572,7 @@ 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)
		@@ -2545,6 +2663,7 @@ 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)