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path: root/drivers/gpio/gpiolib-cdev.c
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Diffstat (limited to 'drivers/gpio/gpiolib-cdev.c')
-rw-r--r--drivers/gpio/gpiolib-cdev.c1121
1 files changed, 1121 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
new file mode 100644
index 000000000000..e6c9b78adfc2
--- /dev/null
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -0,0 +1,1121 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/anon_inodes.h>
+#include <linux/bitmap.h>
+#include <linux/cdev.h>
+#include <linux/compat.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/pinctrl/consumer.h>
+#include <linux/poll.h>
+#include <linux/spinlock.h>
+#include <linux/timekeeping.h>
+#include <linux/uaccess.h>
+#include <uapi/linux/gpio.h>
+
+#include "gpiolib.h"
+#include "gpiolib-cdev.h"
+
+/* 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
+ */
+
+/**
+ * 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,
+ GPIOLINE_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);
+
+ /* Make sure this is terminated */
+ handlereq.consumer_label[sizeof(handlereq.consumer_label)-1] = '\0';
+ if (strlen(handlereq.consumer_label)) {
+ lh->label = kstrdup(handlereq.consumer_label,
+ 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,
+ GPIOLINE_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;
+}
+
+/*
+ * 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;
+}
+
+
+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;
+ int ret;
+
+ if (count < sizeof(ge))
+ 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, sizeof(ge)))
+ return -EFAULT;
+ bytes_read += sizeof(ge);
+ } while (count >= bytes_read + sizeof(ge));
+
+ 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);
+
+ /* Make sure this is terminated */
+ eventreq.consumer_label[sizeof(eventreq.consumer_label)-1] = '\0';
+ if (strlen(eventreq.consumer_label)) {
+ le->label = kstrdup(eventreq.consumer_label,
+ 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,
+ GPIOLINE_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_desc_to_lineinfo(struct gpio_desc *desc,
+ struct gpioline_info *info)
+{
+ struct gpio_chip *gc = desc->gdev->chip;
+ bool ok_for_pinctrl;
+ unsigned long flags;
+
+ /*
+ * 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->line_offset);
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (desc->name) {
+ strncpy(info->name, desc->name, sizeof(info->name));
+ info->name[sizeof(info->name) - 1] = '\0';
+ } else {
+ info->name[0] = '\0';
+ }
+
+ if (desc->label) {
+ strncpy(info->consumer, desc->label, sizeof(info->consumer));
+ info->consumer[sizeof(info->consumer) - 1] = '\0';
+ } else {
+ info->consumer[0] = '\0';
+ }
+
+ /*
+ * 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) ||
+ !ok_for_pinctrl)
+ info->flags |= GPIOLINE_FLAG_KERNEL;
+ if (test_bit(FLAG_IS_OUT, &desc->flags))
+ info->flags |= GPIOLINE_FLAG_IS_OUT;
+ if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+ info->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
+ if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
+ info->flags |= (GPIOLINE_FLAG_OPEN_DRAIN |
+ GPIOLINE_FLAG_IS_OUT);
+ if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
+ info->flags |= (GPIOLINE_FLAG_OPEN_SOURCE |
+ GPIOLINE_FLAG_IS_OUT);
+ if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
+ info->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
+ if (test_bit(FLAG_PULL_DOWN, &desc->flags))
+ info->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
+ if (test_bit(FLAG_PULL_UP, &desc->flags))
+ info->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+}
+
+struct gpio_chardev_data {
+ struct gpio_device *gdev;
+ wait_queue_head_t wait;
+ DECLARE_KFIFO(events, struct gpioline_info_changed, 32);
+ struct notifier_block lineinfo_changed_nb;
+ unsigned long *watched_lines;
+};
+
+/*
+ * 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;
+ struct gpio_chip *gc = gdev->chip;
+ void __user *ip = (void __user *)arg;
+ struct gpio_desc *desc;
+ __u32 offset;
+
+ /* We fail any subsequent ioctl():s when the chip is gone */
+ if (!gc)
+ return -ENODEV;
+
+ /* Fill in the struct and pass to userspace */
+ if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
+ struct gpiochip_info chipinfo;
+
+ memset(&chipinfo, 0, sizeof(chipinfo));
+
+ strncpy(chipinfo.name, dev_name(&gdev->dev),
+ sizeof(chipinfo.name));
+ chipinfo.name[sizeof(chipinfo.name)-1] = '\0';
+ strncpy(chipinfo.label, gdev->label,
+ sizeof(chipinfo.label));
+ chipinfo.label[sizeof(chipinfo.label)-1] = '\0';
+ chipinfo.lines = gdev->ngpio;
+ if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
+ return -EFAULT;
+ return 0;
+ } else if (cmd == GPIO_GET_LINEINFO_IOCTL) {
+ struct gpioline_info lineinfo;
+
+ if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+ return -EFAULT;
+
+ /* this doubles as a range check on line_offset */
+ desc = gpiochip_get_desc(gc, lineinfo.line_offset);
+ if (IS_ERR(desc))
+ return PTR_ERR(desc);
+
+ gpio_desc_to_lineinfo(desc, &lineinfo);
+
+ if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
+ return -EFAULT;
+ return 0;
+ } 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_WATCH_IOCTL) {
+ struct gpioline_info lineinfo;
+
+ if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+ return -EFAULT;
+
+ /* this doubles as a range check on line_offset */
+ desc = gpiochip_get_desc(gc, lineinfo.line_offset);
+ if (IS_ERR(desc))
+ return PTR_ERR(desc);
+
+ if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
+ return -EBUSY;
+
+ gpio_desc_to_lineinfo(desc, &lineinfo);
+
+ if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
+ clear_bit(lineinfo.line_offset, cdev->watched_lines);
+ return -EFAULT;
+ }
+
+ return 0;
+ } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
+ 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;
+ }
+ 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 gpioline_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.info.line_offset = gpio_chip_hwgpio(desc);
+ chg.event_type = action;
+ chg.timestamp = 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 gpioline_info_changed event;
+ ssize_t bytes_read = 0;
+ int ret;
+
+ if (count < sizeof(event))
+ return -EINVAL;
+
+ 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;
+ }
+ }
+
+ 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(). */
+ }
+
+ if (copy_to_user(buf + bytes_read, &event, sizeof(event)))
+ return -EFAULT;
+ bytes_read += sizeof(event);
+ } 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);
+}