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linux/drivers/gpio/gpiolib-cdev.c
Kent Gibson 03a58ea590 gpiolib: cdev: clear debounce period if line set to output 
When set_config changes a line from input to output debounce is
implicitly disabled, as debounce makes no sense for outputs, but the
debounce period is not being cleared and is still reported in the
line info.

So clear the debounce period when the debouncer is stopped in
edge_detector_stop().

Fixes: 65cff70464 ("gpiolib: cdev: support setting debounce")
Cc: stable@vger.kernel.org
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2021-01-27 15:52:13 +01:00

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// SPDX-License-Identifier: GPL-2.0
#include <linux/anon_inodes.h>
#include <linux/atomic.h>
#include <linux/bitmap.h>
#include <linux/build_bug.h>
#include <linux/cdev.h>
#include <linux/compat.h>
#include <linux/compiler.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/file.h>
#include <linux/gpio.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/irqreturn.h>
#include <linux/kernel.h>
#include <linux/kfifo.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pinctrl/consumer.h>
#include <linux/poll.h>
#include <linux/spinlock.h>
#include <linux/timekeeping.h>
#include <linux/uaccess.h>
#include <linux/workqueue.h>
#include <uapi/linux/gpio.h>
#include "gpiolib.h"
#include "gpiolib-cdev.h"
/*
* Array sizes must ensure 64-bit alignment and not create holes in the
* struct packing.
*/
static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
/*
* Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
*/
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
/* Character device interface to GPIO.
*
* The GPIO character device, /dev/gpiochipN, provides userspace an
* interface to gpiolib GPIOs via ioctl()s.
*/
/*
* GPIO line handle management
*/
#ifdef CONFIG_GPIO_CDEV_V1
/**
* struct linehandle_state - contains the state of a userspace handle
* @gdev: the GPIO device the handle pertains to
* @label: consumer label used to tag descriptors
* @descs: the GPIO descriptors held by this handle
* @num_descs: the number of descriptors held in the descs array
*/
struct linehandle_state {
struct gpio_device *gdev;
const char *label;
struct gpio_desc *descs[GPIOHANDLES_MAX];
u32 num_descs;
};
#define GPIOHANDLE_REQUEST_VALID_FLAGS \
(GPIOHANDLE_REQUEST_INPUT | \
GPIOHANDLE_REQUEST_OUTPUT | \
GPIOHANDLE_REQUEST_ACTIVE_LOW | \
GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
GPIOHANDLE_REQUEST_BIAS_DISABLE | \
GPIOHANDLE_REQUEST_OPEN_DRAIN | \
GPIOHANDLE_REQUEST_OPEN_SOURCE)
static int linehandle_validate_flags(u32 flags)
{
/* Return an error if an unknown flag is set */
if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
return -EINVAL;
/*
* Do not allow both INPUT & OUTPUT flags to be set as they are
* contradictory.
*/
if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
(flags & GPIOHANDLE_REQUEST_OUTPUT))
return -EINVAL;
/*
* Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
* the hardware actually supports enabling both at the same time the
* electrical result would be disastrous.
*/
if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
(flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
return -EINVAL;
/* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
(flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
return -EINVAL;
/* Bias flags only allowed for input or output mode. */
if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
(flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
(flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
(flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
return -EINVAL;
/* Only one bias flag can be set. */
if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
(flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
(flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
return -EINVAL;
return 0;
}
static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
{
assign_bit(FLAG_ACTIVE_LOW, flagsp,
lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
assign_bit(FLAG_OPEN_DRAIN, flagsp,
lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
assign_bit(FLAG_OPEN_SOURCE, flagsp,
lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
assign_bit(FLAG_PULL_UP, flagsp,
lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
assign_bit(FLAG_PULL_DOWN, flagsp,
lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
assign_bit(FLAG_BIAS_DISABLE, flagsp,
lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
}
static long linehandle_set_config(struct linehandle_state *lh,
void __user *ip)
{
struct gpiohandle_config gcnf;
struct gpio_desc *desc;
int i, ret;
u32 lflags;
if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
return -EFAULT;
lflags = gcnf.flags;
ret = linehandle_validate_flags(lflags);
if (ret)
return ret;
for (i = 0; i < lh->num_descs; i++) {
desc = lh->descs[i];
linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
/*
* Lines have to be requested explicitly for input
* or output, else the line will be treated "as is".
*/
if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
int val = !!gcnf.default_values[i];
ret = gpiod_direction_output(desc, val);
if (ret)
return ret;
} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
ret = gpiod_direction_input(desc);
if (ret)
return ret;
}
blocking_notifier_call_chain(&desc->gdev->notifier,
GPIO_V2_LINE_CHANGED_CONFIG,
desc);
}
return 0;
}
static long linehandle_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct linehandle_state *lh = file->private_data;
void __user *ip = (void __user *)arg;
struct gpiohandle_data ghd;
DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
int i;
if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
/* NOTE: It's ok to read values of output lines. */
int ret = gpiod_get_array_value_complex(false,
true,
lh->num_descs,
lh->descs,
NULL,
vals);
if (ret)
return ret;
memset(&ghd, 0, sizeof(ghd));
for (i = 0; i < lh->num_descs; i++)
ghd.values[i] = test_bit(i, vals);
if (copy_to_user(ip, &ghd, sizeof(ghd)))
return -EFAULT;
return 0;
} else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) {
/*
* All line descriptors were created at once with the same
* flags so just check if the first one is really output.
*/
if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
return -EPERM;
if (copy_from_user(&ghd, ip, sizeof(ghd)))
return -EFAULT;
/* Clamp all values to [0,1] */
for (i = 0; i < lh->num_descs; i++)
__assign_bit(i, vals, ghd.values[i]);
/* Reuse the array setting function */
return gpiod_set_array_value_complex(false,
true,
lh->num_descs,
lh->descs,
NULL,
vals);
} else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) {
return linehandle_set_config(lh, ip);
}
return -EINVAL;
}
#ifdef CONFIG_COMPAT
static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
unsigned long arg)
{
return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif
static void linehandle_free(struct linehandle_state *lh)
{
int i;
for (i = 0; i < lh->num_descs; i++)
if (lh->descs[i])
gpiod_free(lh->descs[i]);
kfree(lh->label);
put_device(&lh->gdev->dev);
kfree(lh);
}
static int linehandle_release(struct inode *inode, struct file *file)
{
linehandle_free(file->private_data);
return 0;
}
static const struct file_operations linehandle_fileops = {
.release = linehandle_release,
.owner = THIS_MODULE,
.llseek = noop_llseek,
.unlocked_ioctl = linehandle_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = linehandle_ioctl_compat,
#endif
};
static int linehandle_create(struct gpio_device *gdev, void __user *ip)
{
struct gpiohandle_request handlereq;
struct linehandle_state *lh;
struct file *file;
int fd, i, ret;
u32 lflags;
if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
return -EFAULT;
if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
return -EINVAL;
lflags = handlereq.flags;
ret = linehandle_validate_flags(lflags);
if (ret)
return ret;
lh = kzalloc(sizeof(*lh), GFP_KERNEL);
if (!lh)
return -ENOMEM;
lh->gdev = gdev;
get_device(&gdev->dev);
if (handlereq.consumer_label[0] != '\0') {
/* label is only initialized if consumer_label is set */
lh->label = kstrndup(handlereq.consumer_label,
sizeof(handlereq.consumer_label) - 1,
GFP_KERNEL);
if (!lh->label) {
ret = -ENOMEM;
goto out_free_lh;
}
}
lh->num_descs = handlereq.lines;
/* Request each GPIO */
for (i = 0; i < handlereq.lines; i++) {
u32 offset = handlereq.lineoffsets[i];
struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
if (IS_ERR(desc)) {
ret = PTR_ERR(desc);
goto out_free_lh;
}
ret = gpiod_request(desc, lh->label);
if (ret)
goto out_free_lh;
lh->descs[i] = desc;
linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
ret = gpiod_set_transitory(desc, false);
if (ret < 0)
goto out_free_lh;
/*
* Lines have to be requested explicitly for input
* or output, else the line will be treated "as is".
*/
if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
int val = !!handlereq.default_values[i];
ret = gpiod_direction_output(desc, val);
if (ret)
goto out_free_lh;
} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
ret = gpiod_direction_input(desc);
if (ret)
goto out_free_lh;
}
blocking_notifier_call_chain(&desc->gdev->notifier,
GPIO_V2_LINE_CHANGED_REQUESTED, desc);
dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
offset);
}
fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
if (fd < 0) {
ret = fd;
goto out_free_lh;
}
file = anon_inode_getfile("gpio-linehandle",
&linehandle_fileops,
lh,
O_RDONLY | O_CLOEXEC);
if (IS_ERR(file)) {
ret = PTR_ERR(file);
goto out_put_unused_fd;
}
handlereq.fd = fd;
if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
/*
* fput() will trigger the release() callback, so do not go onto
* the regular error cleanup path here.
*/
fput(file);
put_unused_fd(fd);
return -EFAULT;
}
fd_install(fd, file);
dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
lh->num_descs);
return 0;
out_put_unused_fd:
put_unused_fd(fd);
out_free_lh:
linehandle_free(lh);
return ret;
}
#endif /* CONFIG_GPIO_CDEV_V1 */
/**
* struct line - contains the state of a requested line
* @desc: the GPIO descriptor for this line.
* @req: the corresponding line request
* @irq: the interrupt triggered in response to events on this GPIO
* @eflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
* GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
* @timestamp_ns: cache for the timestamp storing it between hardirq and
* IRQ thread, used to bring the timestamp close to the actual event
* @req_seqno: the seqno for the current edge event in the sequence of
* events for the corresponding line request. This is drawn from the @req.
* @line_seqno: the seqno for the current edge event in the sequence of
* events for this line.
* @work: the worker that implements software debouncing
* @sw_debounced: flag indicating if the software debouncer is active
* @level: the current debounced physical level of the line
*/
struct line {
struct gpio_desc *desc;
/*
* -- edge detector specific fields --
*/
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.
*/
u64 eflags;
/*
* timestamp_ns and req_seqno are accessed only by
* edge_irq_handler() and edge_irq_thread(), which are themselves
* mutually exclusive, so no additional protection is necessary.
*/
u64 timestamp_ns;
u32 req_seqno;
/*
* line_seqno is accessed by either edge_irq_thread() or
* debounce_work_func(), which are themselves mutually exclusive,
* so no additional protection is necessary.
*/
u32 line_seqno;
/*
* -- debouncer specific fields --
*/
struct delayed_work work;
/*
* sw_debounce is accessed by linereq_set_config(), which is the
* only setter, and linereq_get_values(), which can live with a
* slightly stale value.
*/
unsigned int sw_debounced;
/*
* level is accessed by debounce_work_func(), which is the only
* setter, and linereq_get_values() which can live with a slightly
* stale value.
*/
unsigned int level;
};
/**
* struct linereq - contains the state of a userspace line request
* @gdev: the GPIO device the line request pertains to
* @label: consumer label used to tag GPIO descriptors
* @num_lines: the number of lines in the lines array
* @wait: wait queue that handles blocking reads of events
* @event_buffer_size: the number of elements allocated in @events
* @events: KFIFO for the GPIO events
* @seqno: the sequence number for edge events generated on all lines in
* 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.
* @lines: the lines held by this line request, with @num_lines elements.
*/
struct linereq {
struct gpio_device *gdev;
const char *label;
u32 num_lines;
wait_queue_head_t wait;
u32 event_buffer_size;
DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
atomic_t seqno;
struct mutex config_mutex;
struct line lines[];
};
#define GPIO_V2_LINE_BIAS_FLAGS \
(GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
GPIO_V2_LINE_FLAG_BIAS_DISABLED)
#define GPIO_V2_LINE_DIRECTION_FLAGS \
(GPIO_V2_LINE_FLAG_INPUT | \
GPIO_V2_LINE_FLAG_OUTPUT)
#define GPIO_V2_LINE_DRIVE_FLAGS \
(GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
GPIO_V2_LINE_FLAG_OPEN_SOURCE)
#define GPIO_V2_LINE_EDGE_FLAGS \
(GPIO_V2_LINE_FLAG_EDGE_RISING | \
GPIO_V2_LINE_FLAG_EDGE_FALLING)
#define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
#define GPIO_V2_LINE_VALID_FLAGS \
(GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
GPIO_V2_LINE_DIRECTION_FLAGS | \
GPIO_V2_LINE_DRIVE_FLAGS | \
GPIO_V2_LINE_EDGE_FLAGS | \
GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
GPIO_V2_LINE_BIAS_FLAGS)
static void linereq_put_event(struct linereq *lr,
struct gpio_v2_line_event *le)
{
bool overflow = false;
spin_lock(&lr->wait.lock);
if (kfifo_is_full(&lr->events)) {
overflow = true;
kfifo_skip(&lr->events);
}
kfifo_in(&lr->events, le, 1);
spin_unlock(&lr->wait.lock);
if (!overflow)
wake_up_poll(&lr->wait, EPOLLIN);
else
pr_debug_ratelimited("event FIFO is full - event dropped\n");
}
static u64 line_event_timestamp(struct line *line)
{
if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
return ktime_get_real_ns();
return ktime_get_ns();
}
static irqreturn_t edge_irq_thread(int irq, void *p)
{
struct line *line = p;
struct linereq *lr = line->req;
struct gpio_v2_line_event le;
u64 eflags;
/* Do not leak kernel stack to userspace */
memset(&le, 0, sizeof(le));
if (line->timestamp_ns) {
le.timestamp_ns = line->timestamp_ns;
} else {
/*
* We may be running from a nested threaded interrupt in
* which case we didn't get the timestamp from
* edge_irq_handler().
*/
le.timestamp_ns = line_event_timestamp(line);
if (lr->num_lines != 1)
line->req_seqno = atomic_inc_return(&lr->seqno);
}
line->timestamp_ns = 0;
eflags = READ_ONCE(line->eflags);
if (eflags == GPIO_V2_LINE_FLAG_EDGE_BOTH) {
int level = gpiod_get_value_cansleep(line->desc);
if (level)
/* Emit low-to-high event */
le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
else
/* Emit high-to-low event */
le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
} else if (eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) {
/* Emit low-to-high event */
le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
} else if (eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) {
/* Emit high-to-low event */
le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
} else {
return IRQ_NONE;
}
line->line_seqno++;
le.line_seqno = line->line_seqno;
le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
le.offset = gpio_chip_hwgpio(line->desc);
linereq_put_event(lr, &le);
return IRQ_HANDLED;
}
static irqreturn_t edge_irq_handler(int irq, void *p)
{
struct line *line = p;
struct linereq *lr = line->req;
/*
* Just store the timestamp in hardirq context so we get it as
* close in time as possible to the actual event.
*/
line->timestamp_ns = line_event_timestamp(line);
if (lr->num_lines != 1)
line->req_seqno = atomic_inc_return(&lr->seqno);
return IRQ_WAKE_THREAD;
}
/*
* returns the current debounced logical value.
*/
static bool debounced_value(struct line *line)
{
bool value;
/*
* minor race - debouncer may be stopped here, so edge_detector_stop()
* must leave the value unchanged so the following will read the level
* from when the debouncer was last running.
*/
value = READ_ONCE(line->level);
if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
value = !value;
return value;
}
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)));
return IRQ_HANDLED;
}
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;
u64 eflags;
level = gpiod_get_raw_value_cansleep(line->desc);
if (level < 0) {
pr_debug_ratelimited("debouncer failed to read line value\n");
return;
}
if (READ_ONCE(line->level) == level)
return;
WRITE_ONCE(line->level, level);
/* -- edge detection -- */
eflags = READ_ONCE(line->eflags);
if (!eflags)
return;
/* switch from physical level to logical - if they differ */
if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
level = !level;
/* ignore edges that are not being monitored */
if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
return;
/* Do not leak kernel stack to userspace */
memset(&le, 0, sizeof(le));
lr = line->req;
le.timestamp_ns = line_event_timestamp(line);
le.offset = gpio_chip_hwgpio(line->desc);
line->line_seqno++;
le.line_seqno = line->line_seqno;
le.seqno = (lr->num_lines == 1) ?
le.line_seqno : atomic_inc_return(&lr->seqno);
if (level)
/* Emit low-to-high event */
le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
else
/* Emit high-to-low event */
le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
linereq_put_event(lr, &le);
}
static int debounce_setup(struct line *line,
unsigned int debounce_period_us)
{
unsigned long irqflags;
int ret, level, irq;
/* try hardware */
ret = gpiod_set_debounce(line->desc, debounce_period_us);
if (!ret) {
WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
return ret;
}
if (ret != -ENOTSUPP)
return ret;
if (debounce_period_us) {
/* setup software debounce */
level = gpiod_get_raw_value_cansleep(line->desc);
if (level < 0)
return level;
irq = gpiod_to_irq(line->desc);
if (irq < 0)
return -ENXIO;
WRITE_ONCE(line->level, level);
irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
ret = request_irq(irq, debounce_irq_handler, irqflags,
line->req->label, line);
if (ret)
return ret;
WRITE_ONCE(line->sw_debounced, 1);
line->irq = irq;
}
return 0;
}
static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
unsigned int line_idx)
{
unsigned int i;
u64 mask = BIT_ULL(line_idx);
for (i = 0; i < lc->num_attrs; i++) {
if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
(lc->attrs[i].mask & mask))
return true;
}
return false;
}
static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
unsigned int line_idx)
{
unsigned int i;
u64 mask = BIT_ULL(line_idx);
for (i = 0; i < lc->num_attrs; i++) {
if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
(lc->attrs[i].mask & mask))
return lc->attrs[i].attr.debounce_period_us;
}
return 0;
}
static void edge_detector_stop(struct line *line)
{
if (line->irq) {
free_irq(line->irq, line);
line->irq = 0;
}
cancel_delayed_work_sync(&line->work);
WRITE_ONCE(line->sw_debounced, 0);
WRITE_ONCE(line->eflags, 0);
if (line->desc)
WRITE_ONCE(line->desc->debounce_period_us, 0);
/* do not change line->level - see comment in debounced_value() */
}
static int edge_detector_setup(struct line *line,
struct gpio_v2_line_config *lc,
unsigned int line_idx,
u64 eflags)
{
u32 debounce_period_us;
unsigned long irqflags = 0;
int irq, ret;
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);
if (ret)
return ret;
WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
}
/* detection disabled or sw debouncer will provide edge detection */
if (!eflags || READ_ONCE(line->sw_debounced))
return 0;
irq = gpiod_to_irq(line->desc);
if (irq < 0)
return -ENXIO;
if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
irqflags |= IRQF_ONESHOT;
/* Request a thread to read the events */
ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
irqflags, line->req->label, line);
if (ret)
return ret;
line->irq = irq;
return 0;
}
static int edge_detector_update(struct line *line,
struct gpio_v2_line_config *lc,
unsigned int line_idx,
u64 eflags, bool polarity_change)
{
unsigned int debounce_period_us =
gpio_v2_line_config_debounce_period(lc, line_idx);
if ((READ_ONCE(line->eflags) == eflags) && !polarity_change &&
(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)) ||
(!debounce_period_us && READ_ONCE(line->sw_debounced)))
edge_detector_stop(line);
return edge_detector_setup(line, lc, line_idx, eflags);
}
static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
unsigned int line_idx)
{
unsigned int i;
u64 mask = BIT_ULL(line_idx);
for (i = 0; i < lc->num_attrs; i++) {
if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
(lc->attrs[i].mask & mask))
return lc->attrs[i].attr.flags;
}
return lc->flags;
}
static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
unsigned int line_idx)
{
unsigned int i;
u64 mask = BIT_ULL(line_idx);
for (i = 0; i < lc->num_attrs; i++) {
if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
(lc->attrs[i].mask & mask))
return !!(lc->attrs[i].attr.values & mask);
}
return 0;
}
static int gpio_v2_line_flags_validate(u64 flags)
{
/* Return an error if an unknown flag is set */
if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
return -EINVAL;
/*
* Do not allow both INPUT and OUTPUT flags to be set as they are
* contradictory.
*/
if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
(flags & GPIO_V2_LINE_FLAG_OUTPUT))
return -EINVAL;
/* Edge detection requires explicit input. */
if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
!(flags & GPIO_V2_LINE_FLAG_INPUT))
return -EINVAL;
/*
* Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
* request. If the hardware actually supports enabling both at the
* same time the electrical result would be disastrous.
*/
if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
(flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
return -EINVAL;
/* Drive requires explicit output direction. */
if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
!(flags & GPIO_V2_LINE_FLAG_OUTPUT))
return -EINVAL;
/* Bias requires explicit direction. */
if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
!(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
return -EINVAL;
/* Only one bias flag can be set. */
if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
(flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
(flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
return -EINVAL;
return 0;
}
static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
unsigned int num_lines)
{
unsigned int i;
u64 flags;
int ret;
if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
return -EINVAL;
if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
return -EINVAL;
for (i = 0; i < num_lines; i++) {
flags = gpio_v2_line_config_flags(lc, i);
ret = gpio_v2_line_flags_validate(flags);
if (ret)
return ret;
/* debounce requires explicit input */
if (gpio_v2_line_config_debounced(lc, i) &&
!(flags & GPIO_V2_LINE_FLAG_INPUT))
return -EINVAL;
}
return 0;
}
static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
unsigned long *flagsp)
{
assign_bit(FLAG_ACTIVE_LOW, flagsp,
flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
set_bit(FLAG_IS_OUT, flagsp);
else if (flags & GPIO_V2_LINE_FLAG_INPUT)
clear_bit(FLAG_IS_OUT, flagsp);
assign_bit(FLAG_EDGE_RISING, flagsp,
flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
assign_bit(FLAG_EDGE_FALLING, flagsp,
flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
assign_bit(FLAG_OPEN_DRAIN, flagsp,
flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
assign_bit(FLAG_OPEN_SOURCE, flagsp,
flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
assign_bit(FLAG_PULL_UP, flagsp,
flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
assign_bit(FLAG_PULL_DOWN, flagsp,
flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
assign_bit(FLAG_BIAS_DISABLE, flagsp,
flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp,
flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
}
static long linereq_get_values(struct linereq *lr, void __user *ip)
{
struct gpio_v2_line_values lv;
DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
struct gpio_desc **descs;
unsigned int i, didx, num_get;
bool val;
int ret;
/* NOTE: It's ok to read values of output lines. */
if (copy_from_user(&lv, ip, sizeof(lv)))
return -EFAULT;
for (num_get = 0, i = 0; i < lr->num_lines; i++) {
if (lv.mask & BIT_ULL(i)) {
num_get++;
descs = &lr->lines[i].desc;
}
}
if (num_get == 0)
return -EINVAL;
if (num_get != 1) {
descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
if (!descs)
return -ENOMEM;
for (didx = 0, i = 0; i < lr->num_lines; i++) {
if (lv.mask & BIT_ULL(i)) {
descs[didx] = lr->lines[i].desc;
didx++;
}
}
}
ret = gpiod_get_array_value_complex(false, true, num_get,
descs, NULL, vals);
if (num_get != 1)
kfree(descs);
if (ret)
return ret;
lv.bits = 0;
for (didx = 0, i = 0; i < lr->num_lines; i++) {
if (lv.mask & BIT_ULL(i)) {
if (lr->lines[i].sw_debounced)
val = debounced_value(&lr->lines[i]);
else
val = test_bit(didx, vals);
if (val)
lv.bits |= BIT_ULL(i);
didx++;
}
}
if (copy_to_user(ip, &lv, sizeof(lv)))
return -EFAULT;
return 0;
}
static long linereq_set_values_unlocked(struct linereq *lr,
struct gpio_v2_line_values *lv)
{
DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
struct gpio_desc **descs;
unsigned int i, didx, num_set;
int ret;
bitmap_zero(vals, GPIO_V2_LINES_MAX);
for (num_set = 0, i = 0; i < lr->num_lines; i++) {
if (lv->mask & BIT_ULL(i)) {
if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
return -EPERM;
if (lv->bits & BIT_ULL(i))
__set_bit(num_set, vals);
num_set++;
descs = &lr->lines[i].desc;
}
}
if (num_set == 0)
return -EINVAL;
if (num_set != 1) {
/* build compacted desc array and values */
descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
if (!descs)
return -ENOMEM;
for (didx = 0, i = 0; i < lr->num_lines; i++) {
if (lv->mask & BIT_ULL(i)) {
descs[didx] = lr->lines[i].desc;
didx++;
}
}
}
ret = gpiod_set_array_value_complex(false, true, num_set,
descs, NULL, vals);
if (num_set != 1)
kfree(descs);
return ret;
}
static long linereq_set_values(struct linereq *lr, void __user *ip)
{
struct gpio_v2_line_values lv;
int ret;
if (copy_from_user(&lv, ip, sizeof(lv)))
return -EFAULT;
mutex_lock(&lr->config_mutex);
ret = linereq_set_values_unlocked(lr, &lv);
mutex_unlock(&lr->config_mutex);
return ret;
}
static long linereq_set_config_unlocked(struct linereq *lr,
struct gpio_v2_line_config *lc)
{
struct gpio_desc *desc;
unsigned int i;
u64 flags;
bool polarity_change;
int ret;
for (i = 0; i < lr->num_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));
gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
/*
* Lines have to be requested explicitly for input
* or output, else the line will be treated "as is".
*/
if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
int val = gpio_v2_line_config_output_value(lc, i);
edge_detector_stop(&lr->lines[i]);
ret = gpiod_direction_output(desc, val);
if (ret)
return ret;
} else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
ret = gpiod_direction_input(desc);
if (ret)
return ret;
ret = edge_detector_update(&lr->lines[i], lc, i,
flags & GPIO_V2_LINE_EDGE_FLAGS,
polarity_change);
if (ret)
return ret;
}
blocking_notifier_call_chain(&desc->gdev->notifier,
GPIO_V2_LINE_CHANGED_CONFIG,
desc);
}
return 0;
}
static long linereq_set_config(struct linereq *lr, void __user *ip)
{
struct gpio_v2_line_config lc;
int ret;
if (copy_from_user(&lc, ip, sizeof(lc)))
return -EFAULT;
ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
if (ret)
return ret;
mutex_lock(&lr->config_mutex);
ret = linereq_set_config_unlocked(lr, &lc);
mutex_unlock(&lr->config_mutex);
return ret;
}
static long linereq_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct linereq *lr = file->private_data;
void __user *ip = (void __user *)arg;
if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
return linereq_get_values(lr, ip);
else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL)
return linereq_set_values(lr, ip);
else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
return linereq_set_config(lr, ip);
return -EINVAL;
}
#ifdef CONFIG_COMPAT
static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
unsigned long arg)
{
return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif
static __poll_t linereq_poll(struct file *file,
struct poll_table_struct *wait)
{
struct linereq *lr = file->private_data;
__poll_t events = 0;
poll_wait(file, &lr->wait, wait);
if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
&lr->wait.lock))
events = EPOLLIN | EPOLLRDNORM;
return events;
}
static ssize_t linereq_read(struct file *file,
char __user *buf,
size_t count,
loff_t *f_ps)
{
struct linereq *lr = file->private_data;
struct gpio_v2_line_event le;
ssize_t bytes_read = 0;
int ret;
if (count < sizeof(le))
return -EINVAL;
do {
spin_lock(&lr->wait.lock);
if (kfifo_is_empty(&lr->events)) {
if (bytes_read) {
spin_unlock(&lr->wait.lock);
return bytes_read;
}
if (file->f_flags & O_NONBLOCK) {
spin_unlock(&lr->wait.lock);
return -EAGAIN;
}
ret = wait_event_interruptible_locked(lr->wait,
!kfifo_is_empty(&lr->events));
if (ret) {
spin_unlock(&lr->wait.lock);
return ret;
}
}
ret = kfifo_out(&lr->events, &le, 1);
spin_unlock(&lr->wait.lock);
if (ret != 1) {
/*
* This should never happen - we were holding the
* lock from the moment we learned the fifo is no
* longer empty until now.
*/
ret = -EIO;
break;
}
if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
return -EFAULT;
bytes_read += sizeof(le);
} while (count >= bytes_read + sizeof(le));
return bytes_read;
}
static void linereq_free(struct linereq *lr)
{
unsigned int i;
for (i = 0; i < lr->num_lines; i++) {
edge_detector_stop(&lr->lines[i]);
if (lr->lines[i].desc)
gpiod_free(lr->lines[i].desc);
}
kfifo_free(&lr->events);
kfree(lr->label);
put_device(&lr->gdev->dev);
kfree(lr);
}
static int linereq_release(struct inode *inode, struct file *file)
{
struct linereq *lr = file->private_data;
linereq_free(lr);
return 0;
}
static const struct file_operations line_fileops = {
.release = linereq_release,
.read = linereq_read,
.poll = linereq_poll,
.owner = THIS_MODULE,
.llseek = noop_llseek,
.unlocked_ioctl = linereq_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = linereq_ioctl_compat,
#endif
};
static int linereq_create(struct gpio_device *gdev, void __user *ip)
{
struct gpio_v2_line_request ulr;
struct gpio_v2_line_config *lc;
struct linereq *lr;
struct file *file;
u64 flags;
unsigned int i;
int fd, ret;
if (copy_from_user(&ulr, ip, sizeof(ulr)))
return -EFAULT;
if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
return -EINVAL;
if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
return -EINVAL;
lc = &ulr.config;
ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
if (ret)
return ret;
lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
if (!lr)
return -ENOMEM;
lr->gdev = gdev;
get_device(&gdev->dev);
for (i = 0; i < ulr.num_lines; i++) {
lr->lines[i].req = lr;
WRITE_ONCE(lr->lines[i].sw_debounced, 0);
INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
}
if (ulr.consumer[0] != '\0') {
/* label is only initialized if consumer is set */
lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
GFP_KERNEL);
if (!lr->label) {
ret = -ENOMEM;
goto out_free_linereq;
}
}
mutex_init(&lr->config_mutex);
init_waitqueue_head(&lr->wait);
lr->event_buffer_size = ulr.event_buffer_size;
if (lr->event_buffer_size == 0)
lr->event_buffer_size = ulr.num_lines * 16;
else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
atomic_set(&lr->seqno, 0);
lr->num_lines = ulr.num_lines;
/* Request each GPIO */
for (i = 0; i < ulr.num_lines; i++) {
u32 offset = ulr.offsets[i];
struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
if (IS_ERR(desc)) {
ret = PTR_ERR(desc);
goto out_free_linereq;
}
ret = gpiod_request(desc, lr->label);
if (ret)
goto out_free_linereq;
lr->lines[i].desc = desc;
flags = gpio_v2_line_config_flags(lc, i);
gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
ret = gpiod_set_transitory(desc, false);
if (ret < 0)
goto out_free_linereq;
/*
* Lines have to be requested explicitly for input
* or output, else the line will be treated "as is".
*/
if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
int val = gpio_v2_line_config_output_value(lc, i);
ret = gpiod_direction_output(desc, val);
if (ret)
goto out_free_linereq;
} else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
ret = gpiod_direction_input(desc);
if (ret)
goto out_free_linereq;
ret = edge_detector_setup(&lr->lines[i], lc, i,
flags & GPIO_V2_LINE_EDGE_FLAGS);
if (ret)
goto out_free_linereq;
}
blocking_notifier_call_chain(&desc->gdev->notifier,
GPIO_V2_LINE_CHANGED_REQUESTED, desc);
dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
offset);
}
fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
if (fd < 0) {
ret = fd;
goto out_free_linereq;
}
file = anon_inode_getfile("gpio-line", &line_fileops, lr,
O_RDONLY | O_CLOEXEC);
if (IS_ERR(file)) {
ret = PTR_ERR(file);
goto out_put_unused_fd;
}
ulr.fd = fd;
if (copy_to_user(ip, &ulr, sizeof(ulr))) {
/*
* fput() will trigger the release() callback, so do not go onto
* the regular error cleanup path here.
*/
fput(file);
put_unused_fd(fd);
return -EFAULT;
}
fd_install(fd, file);
dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
lr->num_lines);
return 0;
out_put_unused_fd:
put_unused_fd(fd);
out_free_linereq:
linereq_free(lr);
return ret;
}
#ifdef CONFIG_GPIO_CDEV_V1
/*
* GPIO line event management
*/
/**
* struct lineevent_state - contains the state of a userspace event
* @gdev: the GPIO device the event pertains to
* @label: consumer label used to tag descriptors
* @desc: the GPIO descriptor held by this event
* @eflags: the event flags this line was requested with
* @irq: the interrupt that trigger in response to events on this GPIO
* @wait: wait queue that handles blocking reads of events
* @events: KFIFO for the GPIO events
* @timestamp: cache for the timestamp storing it between hardirq
* and IRQ thread, used to bring the timestamp close to the actual
* event
*/
struct lineevent_state {
struct gpio_device *gdev;
const char *label;
struct gpio_desc *desc;
u32 eflags;
int irq;
wait_queue_head_t wait;
DECLARE_KFIFO(events, struct gpioevent_data, 16);
u64 timestamp;
};
#define GPIOEVENT_REQUEST_VALID_FLAGS \
(GPIOEVENT_REQUEST_RISING_EDGE | \
GPIOEVENT_REQUEST_FALLING_EDGE)
static __poll_t lineevent_poll(struct file *file,
struct poll_table_struct *wait)
{
struct lineevent_state *le = file->private_data;
__poll_t events = 0;
poll_wait(file, &le->wait, wait);
if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
events = EPOLLIN | EPOLLRDNORM;
return events;
}
struct compat_gpioeevent_data {
compat_u64 timestamp;
u32 id;
};
static ssize_t lineevent_read(struct file *file,
char __user *buf,
size_t count,
loff_t *f_ps)
{
struct lineevent_state *le = file->private_data;
struct gpioevent_data ge;
ssize_t bytes_read = 0;
ssize_t ge_size;
int ret;
/*
* When compatible system call is being used the struct gpioevent_data,
* in case of at least ia32, has different size due to the alignment
* differences. Because we have first member 64 bits followed by one of
* 32 bits there is no gap between them. The only difference is the
* padding at the end of the data structure. Hence, we calculate the
* actual sizeof() and pass this as an argument to copy_to_user() to
* drop unneeded bytes from the output.
*/
if (compat_need_64bit_alignment_fixup())
ge_size = sizeof(struct compat_gpioeevent_data);
else
ge_size = sizeof(struct gpioevent_data);
if (count < ge_size)
return -EINVAL;
do {
spin_lock(&le->wait.lock);
if (kfifo_is_empty(&le->events)) {
if (bytes_read) {
spin_unlock(&le->wait.lock);
return bytes_read;
}
if (file->f_flags & O_NONBLOCK) {
spin_unlock(&le->wait.lock);
return -EAGAIN;
}
ret = wait_event_interruptible_locked(le->wait,
!kfifo_is_empty(&le->events));
if (ret) {
spin_unlock(&le->wait.lock);
return ret;
}
}
ret = kfifo_out(&le->events, &ge, 1);
spin_unlock(&le->wait.lock);
if (ret != 1) {
/*
* This should never happen - we were holding the lock
* from the moment we learned the fifo is no longer
* empty until now.
*/
ret = -EIO;
break;
}
if (copy_to_user(buf + bytes_read, &ge, ge_size))
return -EFAULT;
bytes_read += ge_size;
} while (count >= bytes_read + ge_size);
return bytes_read;
}
static void lineevent_free(struct lineevent_state *le)
{
if (le->irq)
free_irq(le->irq, le);
if (le->desc)
gpiod_free(le->desc);
kfree(le->label);
put_device(&le->gdev->dev);
kfree(le);
}
static int lineevent_release(struct inode *inode, struct file *file)
{
lineevent_free(file->private_data);
return 0;
}
static long lineevent_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct lineevent_state *le = file->private_data;
void __user *ip = (void __user *)arg;
struct gpiohandle_data ghd;
/*
* We can get the value for an event line but not set it,
* because it is input by definition.
*/
if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
int val;
memset(&ghd, 0, sizeof(ghd));
val = gpiod_get_value_cansleep(le->desc);
if (val < 0)
return val;
ghd.values[0] = val;
if (copy_to_user(ip, &ghd, sizeof(ghd)))
return -EFAULT;
return 0;
}
return -EINVAL;
}
#ifdef CONFIG_COMPAT
static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
unsigned long arg)
{
return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif
static const struct file_operations lineevent_fileops = {
.release = lineevent_release,
.read = lineevent_read,
.poll = lineevent_poll,
.owner = THIS_MODULE,
.llseek = noop_llseek,
.unlocked_ioctl = lineevent_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = lineevent_ioctl_compat,
#endif
};
static irqreturn_t lineevent_irq_thread(int irq, void *p)
{
struct lineevent_state *le = p;
struct gpioevent_data ge;
int ret;
/* Do not leak kernel stack to userspace */
memset(&ge, 0, sizeof(ge));
/*
* We may be running from a nested threaded interrupt in which case
* we didn't get the timestamp from lineevent_irq_handler().
*/
if (!le->timestamp)
ge.timestamp = ktime_get_ns();
else
ge.timestamp = le->timestamp;
if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
&& le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
int level = gpiod_get_value_cansleep(le->desc);
if (level)
/* Emit low-to-high event */
ge.id = GPIOEVENT_EVENT_RISING_EDGE;
else
/* Emit high-to-low event */
ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
} else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
/* Emit low-to-high event */
ge.id = GPIOEVENT_EVENT_RISING_EDGE;
} else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
/* Emit high-to-low event */
ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
} else {
return IRQ_NONE;
}
ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
1, &le->wait.lock);
if (ret)
wake_up_poll(&le->wait, EPOLLIN);
else
pr_debug_ratelimited("event FIFO is full - event dropped\n");
return IRQ_HANDLED;
}
static irqreturn_t lineevent_irq_handler(int irq, void *p)
{
struct lineevent_state *le = p;
/*
* Just store the timestamp in hardirq context so we get it as
* close in time as possible to the actual event.
*/
le->timestamp = ktime_get_ns();
return IRQ_WAKE_THREAD;
}
static int lineevent_create(struct gpio_device *gdev, void __user *ip)
{
struct gpioevent_request eventreq;
struct lineevent_state *le;
struct gpio_desc *desc;
struct file *file;
u32 offset;
u32 lflags;
u32 eflags;
int fd;
int ret;
int irq, irqflags = 0;
if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
return -EFAULT;
offset = eventreq.lineoffset;
lflags = eventreq.handleflags;
eflags = eventreq.eventflags;
desc = gpiochip_get_desc(gdev->chip, offset);
if (IS_ERR(desc))
return PTR_ERR(desc);
/* Return an error if a unknown flag is set */
if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
(eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
return -EINVAL;
/* This is just wrong: we don't look for events on output lines */
if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
(lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
(lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
return -EINVAL;
/* Only one bias flag can be set. */
if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
(lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
(lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
return -EINVAL;
le = kzalloc(sizeof(*le), GFP_KERNEL);
if (!le)
return -ENOMEM;
le->gdev = gdev;
get_device(&gdev->dev);
if (eventreq.consumer_label[0] != '\0') {
/* label is only initialized if consumer_label is set */
le->label = kstrndup(eventreq.consumer_label,
sizeof(eventreq.consumer_label) - 1,
GFP_KERNEL);
if (!le->label) {
ret = -ENOMEM;
goto out_free_le;
}
}
ret = gpiod_request(desc, le->label);
if (ret)
goto out_free_le;
le->desc = desc;
le->eflags = eflags;
linehandle_flags_to_desc_flags(lflags, &desc->flags);
ret = gpiod_direction_input(desc);
if (ret)
goto out_free_le;
blocking_notifier_call_chain(&desc->gdev->notifier,
GPIO_V2_LINE_CHANGED_REQUESTED, desc);
irq = gpiod_to_irq(desc);
if (irq <= 0) {
ret = -ENODEV;
goto out_free_le;
}
le->irq = irq;
if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
irqflags |= IRQF_ONESHOT;
INIT_KFIFO(le->events);
init_waitqueue_head(&le->wait);
/* Request a thread to read the events */
ret = request_threaded_irq(le->irq,
lineevent_irq_handler,
lineevent_irq_thread,
irqflags,
le->label,
le);
if (ret)
goto out_free_le;
fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
if (fd < 0) {
ret = fd;
goto out_free_le;
}
file = anon_inode_getfile("gpio-event",
&lineevent_fileops,
le,
O_RDONLY | O_CLOEXEC);
if (IS_ERR(file)) {
ret = PTR_ERR(file);
goto out_put_unused_fd;
}
eventreq.fd = fd;
if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
/*
* fput() will trigger the release() callback, so do not go onto
* the regular error cleanup path here.
*/
fput(file);
put_unused_fd(fd);
return -EFAULT;
}
fd_install(fd, file);
return 0;
out_put_unused_fd:
put_unused_fd(fd);
out_free_le:
lineevent_free(le);
return ret;
}
static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
struct gpioline_info *info_v1)
{
u64 flagsv2 = info_v2->flags;
memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
info_v1->line_offset = info_v2->offset;
info_v1->flags = 0;
if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
info_v1->flags |= GPIOLINE_FLAG_KERNEL;
if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
}
static void gpio_v2_line_info_changed_to_v1(
struct gpio_v2_line_info_changed *lic_v2,
struct gpioline_info_changed *lic_v1)
{
gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
lic_v1->timestamp = lic_v2->timestamp_ns;
lic_v1->event_type = lic_v2->event_type;
}
#endif /* CONFIG_GPIO_CDEV_V1 */
static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
struct gpio_v2_line_info *info)
{
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);
/*
* This function takes a mutex so we must check this before taking
* the spinlock.
*
* FIXME: find a non-racy way to retrieve this information. Maybe a
* lock common to both frameworks?
*/
ok_for_pinctrl =
pinctrl_gpio_can_use_line(gc->base + info->offset);
spin_lock_irqsave(&gpio_lock, flags);
if (desc->name)
strscpy(info->name, desc->name, sizeof(info->name));
if (desc->label)
strscpy(info->consumer, desc->label, sizeof(info->consumer));
/*
* Userspace only need to know that the kernel is using this GPIO so
* it can't use it.
*/
info->flags = 0;
if (test_bit(FLAG_REQUESTED, &desc->flags) ||
test_bit(FLAG_IS_HOGGED, &desc->flags) ||
test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
test_bit(FLAG_EXPORT, &desc->flags) ||
test_bit(FLAG_SYSFS, &desc->flags) ||
!gpiochip_line_is_valid(gc, info->offset) ||
!ok_for_pinctrl)
info->flags |= GPIO_V2_LINE_FLAG_USED;
if (test_bit(FLAG_IS_OUT, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
else
info->flags |= GPIO_V2_LINE_FLAG_INPUT;
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
if (test_bit(FLAG_PULL_DOWN, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
if (test_bit(FLAG_PULL_UP, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
if (test_bit(FLAG_EDGE_RISING, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags))
info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
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);
}
struct gpio_chardev_data {
struct gpio_device *gdev;
wait_queue_head_t wait;
DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
struct notifier_block lineinfo_changed_nb;
unsigned long *watched_lines;
#ifdef CONFIG_GPIO_CDEV_V1
atomic_t watch_abi_version;
#endif
};
static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
{
struct gpio_device *gdev = cdev->gdev;
struct gpiochip_info chipinfo;
memset(&chipinfo, 0, sizeof(chipinfo));
strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
chipinfo.lines = gdev->ngpio;
if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
return -EFAULT;
return 0;
}
#ifdef CONFIG_GPIO_CDEV_V1
/*
* returns 0 if the versions match, else the previously selected ABI version
*/
static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
unsigned int version)
{
int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
if (abiv == version)
return 0;
return abiv;
}
static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
bool watch)
{
struct gpio_desc *desc;
struct gpioline_info lineinfo;
struct gpio_v2_line_info lineinfo_v2;
if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
return -EFAULT;
/* this doubles as a range check on line_offset */
desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
if (IS_ERR(desc))
return PTR_ERR(desc);
if (watch) {
if (lineinfo_ensure_abi_version(cdev, 1))
return -EPERM;
if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
return -EBUSY;
}
gpio_desc_to_lineinfo(desc, &lineinfo_v2);
gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
if (watch)
clear_bit(lineinfo.line_offset, cdev->watched_lines);
return -EFAULT;
}
return 0;
}
#endif
static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
bool watch)
{
struct gpio_desc *desc;
struct gpio_v2_line_info lineinfo;
if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
return -EFAULT;
if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
return -EINVAL;
desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
if (IS_ERR(desc))
return PTR_ERR(desc);
if (watch) {
#ifdef CONFIG_GPIO_CDEV_V1
if (lineinfo_ensure_abi_version(cdev, 2))
return -EPERM;
#endif
if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
return -EBUSY;
}
gpio_desc_to_lineinfo(desc, &lineinfo);
if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
if (watch)
clear_bit(lineinfo.offset, cdev->watched_lines);
return -EFAULT;
}
return 0;
}
static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
{
__u32 offset;
if (copy_from_user(&offset, ip, sizeof(offset)))
return -EFAULT;
if (offset >= cdev->gdev->ngpio)
return -EINVAL;
if (!test_and_clear_bit(offset, cdev->watched_lines))
return -EBUSY;
return 0;
}
/*
* gpio_ioctl() - ioctl handler for the GPIO chardev
*/
static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct gpio_chardev_data *cdev = file->private_data;
struct gpio_device *gdev = cdev->gdev;
void __user *ip = (void __user *)arg;
/* We fail any subsequent ioctl():s when the chip is gone */
if (!gdev->chip)
return -ENODEV;
/* Fill in the struct and pass to userspace */
if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
return chipinfo_get(cdev, ip);
#ifdef CONFIG_GPIO_CDEV_V1
} else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
return linehandle_create(gdev, ip);
} else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
return lineevent_create(gdev, ip);
} else if (cmd == GPIO_GET_LINEINFO_IOCTL ||
cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
return lineinfo_get_v1(cdev, ip,
cmd == GPIO_GET_LINEINFO_WATCH_IOCTL);
#endif /* CONFIG_GPIO_CDEV_V1 */
} else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL ||
cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) {
return lineinfo_get(cdev, ip,
cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL);
} else if (cmd == GPIO_V2_GET_LINE_IOCTL) {
return linereq_create(gdev, ip);
} else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
return lineinfo_unwatch(cdev, ip);
}
return -EINVAL;
}
#ifdef CONFIG_COMPAT
static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
unsigned long arg)
{
return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif
static struct gpio_chardev_data *
to_gpio_chardev_data(struct notifier_block *nb)
{
return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
}
static int lineinfo_changed_notify(struct notifier_block *nb,
unsigned long action, void *data)
{
struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb);
struct gpio_v2_line_info_changed chg;
struct gpio_desc *desc = data;
int ret;
if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
return NOTIFY_DONE;
memset(&chg, 0, sizeof(chg));
chg.event_type = action;
chg.timestamp_ns = ktime_get_ns();
gpio_desc_to_lineinfo(desc, &chg.info);
ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
if (ret)
wake_up_poll(&cdev->wait, EPOLLIN);
else
pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
return NOTIFY_OK;
}
static __poll_t lineinfo_watch_poll(struct file *file,
struct poll_table_struct *pollt)
{
struct gpio_chardev_data *cdev = file->private_data;
__poll_t events = 0;
poll_wait(file, &cdev->wait, pollt);
if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
&cdev->wait.lock))
events = EPOLLIN | EPOLLRDNORM;
return events;
}
static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
size_t count, loff_t *off)
{
struct gpio_chardev_data *cdev = file->private_data;
struct gpio_v2_line_info_changed event;
ssize_t bytes_read = 0;
int ret;
size_t event_size;
#ifndef CONFIG_GPIO_CDEV_V1
event_size = sizeof(struct gpio_v2_line_info_changed);
if (count < event_size)
return -EINVAL;
#endif
do {
spin_lock(&cdev->wait.lock);
if (kfifo_is_empty(&cdev->events)) {
if (bytes_read) {
spin_unlock(&cdev->wait.lock);
return bytes_read;
}
if (file->f_flags & O_NONBLOCK) {
spin_unlock(&cdev->wait.lock);
return -EAGAIN;
}
ret = wait_event_interruptible_locked(cdev->wait,
!kfifo_is_empty(&cdev->events));
if (ret) {
spin_unlock(&cdev->wait.lock);
return ret;
}
}
#ifdef CONFIG_GPIO_CDEV_V1
/* must be after kfifo check so watch_abi_version is set */
if (atomic_read(&cdev->watch_abi_version) == 2)
event_size = sizeof(struct gpio_v2_line_info_changed);
else
event_size = sizeof(struct gpioline_info_changed);
if (count < event_size) {
spin_unlock(&cdev->wait.lock);
return -EINVAL;
}
#endif
ret = kfifo_out(&cdev->events, &event, 1);
spin_unlock(&cdev->wait.lock);
if (ret != 1) {
ret = -EIO;
break;
/* We should never get here. See lineevent_read(). */
}
#ifdef CONFIG_GPIO_CDEV_V1
if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
if (copy_to_user(buf + bytes_read, &event, event_size))
return -EFAULT;
} else {
struct gpioline_info_changed event_v1;
gpio_v2_line_info_changed_to_v1(&event, &event_v1);
if (copy_to_user(buf + bytes_read, &event_v1,
event_size))
return -EFAULT;
}
#else
if (copy_to_user(buf + bytes_read, &event, event_size))
return -EFAULT;
#endif
bytes_read += event_size;
} while (count >= bytes_read + sizeof(event));
return bytes_read;
}
/**
* gpio_chrdev_open() - open the chardev for ioctl operations
* @inode: inode for this chardev
* @file: file struct for storing private data
* Returns 0 on success
*/
static int gpio_chrdev_open(struct inode *inode, struct file *file)
{
struct gpio_device *gdev = container_of(inode->i_cdev,
struct gpio_device, chrdev);
struct gpio_chardev_data *cdev;
int ret = -ENOMEM;
/* Fail on open if the backing gpiochip is gone */
if (!gdev->chip)
return -ENODEV;
cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
if (!cdev)
return -ENOMEM;
cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
if (!cdev->watched_lines)
goto out_free_cdev;
init_waitqueue_head(&cdev->wait);
INIT_KFIFO(cdev->events);
cdev->gdev = gdev;
cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
ret = blocking_notifier_chain_register(&gdev->notifier,
&cdev->lineinfo_changed_nb);
if (ret)
goto out_free_bitmap;
get_device(&gdev->dev);
file->private_data = cdev;
ret = nonseekable_open(inode, file);
if (ret)
goto out_unregister_notifier;
return ret;
out_unregister_notifier:
blocking_notifier_chain_unregister(&gdev->notifier,
&cdev->lineinfo_changed_nb);
out_free_bitmap:
bitmap_free(cdev->watched_lines);
out_free_cdev:
kfree(cdev);
return ret;
}
/**
* gpio_chrdev_release() - close chardev after ioctl operations
* @inode: inode for this chardev
* @file: file struct for storing private data
* Returns 0 on success
*/
static int gpio_chrdev_release(struct inode *inode, struct file *file)
{
struct gpio_chardev_data *cdev = file->private_data;
struct gpio_device *gdev = cdev->gdev;
bitmap_free(cdev->watched_lines);
blocking_notifier_chain_unregister(&gdev->notifier,
&cdev->lineinfo_changed_nb);
put_device(&gdev->dev);
kfree(cdev);
return 0;
}
static const struct file_operations gpio_fileops = {
.release = gpio_chrdev_release,
.open = gpio_chrdev_open,
.poll = lineinfo_watch_poll,
.read = lineinfo_watch_read,
.owner = THIS_MODULE,
.llseek = no_llseek,
.unlocked_ioctl = gpio_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = gpio_ioctl_compat,
#endif
};
int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
{
int ret;
cdev_init(&gdev->chrdev, &gpio_fileops);
gdev->chrdev.owner = THIS_MODULE;
gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
if (ret)
return ret;
chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
MAJOR(devt), gdev->id);
return 0;
}
void gpiolib_cdev_unregister(struct gpio_device *gdev)
{
cdev_device_del(&gdev->chrdev, &gdev->dev);
}
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