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gpiolib: cdev: consolidate edge detector configuration flags 

Combine the polarity_change flag, struct line eflags, and hte enable
flag into a single flag variable.

The combination of these flags describes the configuration state
of the edge detector, so formalize and clarify that by combining
them into a single variable, edflags, in struct line.

The edflags is a subset of the GPIO_V2_LINE_FLAGsb relevant to
the edge detector, and is also a superset of the eflags it replaces.
The eflags name is still used to describe the subset of edflags
corresponding to the rising/falling edge flags where edflags is
masked down to that subset.

This consolidation reduces the number of variables being passed,
simplifies state comparisons, and provides a more extensible
foundation should additional edge sources be integrated in the
future.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
This commit is contained in:
Kent Gibson 2022-07-14 10:03:18 +08:00 committed by Bartosz Golaszewski
parent 242202329f
commit b1a92e9456
1 changed files with 60 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

126
drivers/gpio/gpiolib-cdev.c
View File

@ -430,12 +430,15 @@ struct line {
struct linereq *req;
unsigned int irq;
/*
* eflags is set by edge_detector_setup(), edge_detector_stop() and
* edge_detector_update(), which are themselves mutually exclusive,
* and is accessed by edge_irq_thread() and debounce_work_func(),
* which can both live with a slightly stale value.
* The flags for the active edge detector configuration.
*
* edflags is set by linereq_create(), linereq_free(), and
* linereq_set_config_unlocked(), which are themselves mutually
* exclusive, and is accessed by edge_irq_thread(),
* process_hw_ts_thread() and debounce_work_func(),
* which can all live with a slightly stale value.
*/
u64 eflags;
u64 edflags;
/*
* timestamp_ns and req_seqno are accessed only by
* edge_irq_handler() and edge_irq_thread(), which are themselves
@ -541,6 +544,12 @@ struct linereq {
GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
GPIO_V2_LINE_BIAS_FLAGS)
/* subset of flags relevant for edge detector configuration */
#define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
(GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
GPIO_V2_LINE_EDGE_FLAGS)
static void linereq_put_event(struct linereq *lr,
struct gpio_v2_line_event *le)
{
@ -580,8 +589,8 @@ static enum hte_return process_hw_ts_thread(void *p)
struct line *line;
struct linereq *lr;
struct gpio_v2_line_event le;
u64 edflags;
int level;
u64 eflags;
if (!p)
return HTE_CB_HANDLED;
@ -592,15 +601,15 @@ static enum hte_return process_hw_ts_thread(void *p)
memset(&le, 0, sizeof(le));
le.timestamp_ns = line->timestamp_ns;
eflags = READ_ONCE(line->eflags);
edflags = READ_ONCE(line->edflags);
switch (eflags) {
switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
case GPIO_V2_LINE_FLAG_EDGE_BOTH:
level = (line->raw_level >= 0) ?
line->raw_level :
gpiod_get_raw_value_cansleep(line->desc);
if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
level = !level;
le.id = line_event_id(level);
@ -681,7 +690,7 @@ static irqreturn_t edge_irq_thread(int irq, void *p)
}
line->timestamp_ns = 0;
switch (READ_ONCE(line->eflags)) {
switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
case GPIO_V2_LINE_FLAG_EDGE_BOTH:
le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
break;
@ -756,16 +765,13 @@ static void debounce_work_func(struct work_struct *work)
struct gpio_v2_line_event le;
struct line *line = container_of(work, struct line, work.work);
struct linereq *lr;
int level, diff_seqno;
u64 eflags;
u64 eflags, edflags = READ_ONCE(line->edflags);
int level = -1, diff_seqno;
if (test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags)) {
if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
level = line->raw_level;
if (level < 0)
level = gpiod_get_raw_value_cansleep(line->desc);
} else {
if (level < 0)
level = gpiod_get_raw_value_cansleep(line->desc);
}
if (level < 0) {
pr_debug_ratelimited("debouncer failed to read line value\n");
return;
@ -777,12 +783,12 @@ static void debounce_work_func(struct work_struct *work)
WRITE_ONCE(line->level, level);
/* -- edge detection -- */
eflags = READ_ONCE(line->eflags);
eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
if (!eflags)
return;
/* switch from physical level to logical - if they differ */
if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
level = !level;
/* ignore edges that are not being monitored */
@ -796,7 +802,7 @@ static void debounce_work_func(struct work_struct *work)
lr = line->req;
le.timestamp_ns = line_event_timestamp(line);
le.offset = gpio_chip_hwgpio(line->desc);
if (test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags)) {
if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
/* discard events except the last one */
line->total_discard_seq -= 1;
diff_seqno = line->last_seqno - line->total_discard_seq -
@ -843,8 +849,7 @@ static int hte_edge_setup(struct line *line, u64 eflags)
process_hw_ts_thread, line);
}
static int debounce_setup(struct line *line,
unsigned int debounce_period_us, bool hte_req)
static int debounce_setup(struct line *line, unsigned int debounce_period_us)
{
unsigned long irqflags;
int ret, level, irq;
@ -864,7 +869,7 @@ static int debounce_setup(struct line *line,
if (level < 0)
return level;
if (!hte_req) {
if (!test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags)) {
irq = gpiod_to_irq(line->desc);
if (irq < 0)
return -ENXIO;
@ -915,19 +920,19 @@ static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
return 0;
}
static void edge_detector_stop(struct line *line, bool hte_en)
static void edge_detector_stop(struct line *line)
{
if (line->irq && !hte_en) {
if (line->irq) {
free_irq(line->irq, line);
line->irq = 0;
}
if (hte_en)
if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
hte_ts_put(&line->hdesc);
cancel_delayed_work_sync(&line->work);
WRITE_ONCE(line->sw_debounced, 0);
WRITE_ONCE(line->eflags, 0);
WRITE_ONCE(line->edflags, 0);
if (line->desc)
WRITE_ONCE(line->desc->debounce_period_us, 0);
/* do not change line->level - see comment in debounced_value() */
@ -935,23 +940,23 @@ static void edge_detector_stop(struct line *line, bool hte_en)
static int edge_detector_setup(struct line *line,
struct gpio_v2_line_config *lc,
unsigned int line_idx,
u64 eflags, bool hte_req)
unsigned int line_idx, u64 edflags)
{
u32 debounce_period_us;
unsigned long irqflags = 0;
u64 eflags;
int irq, ret;
eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
if (eflags && !kfifo_initialized(&line->req->events)) {
ret = kfifo_alloc(&line->req->events,
line->req->event_buffer_size, GFP_KERNEL);
if (ret)
return ret;
}
WRITE_ONCE(line->eflags, eflags);
if (gpio_v2_line_config_debounced(lc, line_idx)) {
debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
ret = debounce_setup(line, debounce_period_us, hte_req);
ret = debounce_setup(line, debounce_period_us);
if (ret)
return ret;
WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
@ -961,8 +966,8 @@ static int edge_detector_setup(struct line *line,
if (!eflags || READ_ONCE(line->sw_debounced))
return 0;
if (hte_req)
return hte_edge_setup(line, eflags);
if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
return hte_edge_setup(line, edflags);
irq = gpiod_to_irq(line->desc);
if (irq < 0)
@ -988,35 +993,29 @@ static int edge_detector_setup(struct line *line,
static int edge_detector_update(struct line *line,
struct gpio_v2_line_config *lc,
unsigned int line_idx,
u64 flags, bool polarity_change,
bool prev_hte_flag)
unsigned int line_idx, u64 edflags)
{
u64 eflags = flags & GPIO_V2_LINE_EDGE_FLAGS;
u64 active_edflags = READ_ONCE(line->edflags);
unsigned int debounce_period_us =
gpio_v2_line_config_debounce_period(lc, line_idx);
bool hte_change = (prev_hte_flag !=
((flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) != 0));
if ((READ_ONCE(line->eflags) == eflags) && !polarity_change &&
(READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)
&& !hte_change)
if ((active_edflags == edflags) &&
(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)) {
WRITE_ONCE(line->eflags, eflags);
WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
return 0;
}
/* reconfiguring edge detection or sw debounce being disabled */
if ((line->irq && !READ_ONCE(line->sw_debounced)) || prev_hte_flag ||
if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
(active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
(!debounce_period_us && READ_ONCE(line->sw_debounced)))
edge_detector_stop(line, prev_hte_flag);
edge_detector_stop(line);
return edge_detector_setup(line, lc, line_idx, eflags,
flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
return edge_detector_setup(line, lc, line_idx, edflags);
}
static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
@ -1285,22 +1284,17 @@ static long linereq_set_config_unlocked(struct linereq *lr,
struct gpio_v2_line_config *lc)
{
struct gpio_desc *desc;
struct line *line;
unsigned int i;
u64 flags;
bool polarity_change;
bool prev_hte_flag;
u64 flags, edflags;
int ret;
for (i = 0; i < lr->num_lines; i++) {
line = &lr->lines[i];
desc = lr->lines[i].desc;
flags = gpio_v2_line_config_flags(lc, i);
polarity_change =
(!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) !=
((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0));
prev_hte_flag = !!test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags);
gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
/*
* Lines have to be requested explicitly for input
* or output, else the line will be treated "as is".
@ -1308,7 +1302,7 @@ static long linereq_set_config_unlocked(struct linereq *lr,
if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
int val = gpio_v2_line_config_output_value(lc, i);
edge_detector_stop(&lr->lines[i], prev_hte_flag);
edge_detector_stop(line);
ret = gpiod_direction_output(desc, val);
if (ret)
return ret;
@ -1317,12 +1311,13 @@ static long linereq_set_config_unlocked(struct linereq *lr,
if (ret)
return ret;
ret = edge_detector_update(&lr->lines[i], lc, i,
flags, polarity_change, prev_hte_flag);
ret = edge_detector_update(line, lc, i, edflags);
if (ret)
return ret;
}
WRITE_ONCE(line->edflags, edflags);
blocking_notifier_call_chain(&desc->gdev->notifier,
GPIO_V2_LINE_CHANGED_CONFIG,
desc);
@ -1449,13 +1444,10 @@ static ssize_t linereq_read(struct file *file,
static void linereq_free(struct linereq *lr)
{
unsigned int i;
bool hte;
for (i = 0; i < lr->num_lines; i++) {
if (lr->lines[i].desc) {
hte = !!test_bit(FLAG_EVENT_CLOCK_HTE,
&lr->lines[i].desc->flags);
edge_detector_stop(&lr->lines[i], hte);
edge_detector_stop(&lr->lines[i]);
gpiod_free(lr->lines[i].desc);
}
}
@ -1491,7 +1483,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
struct gpio_v2_line_config *lc;
struct linereq *lr;
struct file *file;
u64 flags;
u64 flags, edflags;
unsigned int i;
int fd, ret;
@ -1565,6 +1557,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
if (ret < 0)
goto out_free_linereq;
edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
/*
* Lines have to be requested explicitly for input
* or output, else the line will be treated "as is".
@ -1581,12 +1574,13 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
goto out_free_linereq;
ret = edge_detector_setup(&lr->lines[i], lc, i,
flags & GPIO_V2_LINE_EDGE_FLAGS,
flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
edflags);
if (ret)
goto out_free_linereq;
}
lr->lines[i].edflags = edflags;
blocking_notifier_call_chain(&desc->gdev->notifier,
GPIO_V2_LINE_CHANGED_REQUESTED, desc);