diff options
Diffstat (limited to 'drivers/gpio/gpiolib.c')
-rw-r--r-- | drivers/gpio/gpiolib.c | 590 |
1 files changed, 542 insertions, 48 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 24f60d28f0c0..53ff25ac66d8 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -16,11 +16,14 @@ #include <linux/gpio/driver.h> #include <linux/gpio/machine.h> #include <linux/pinctrl/consumer.h> -#include <linux/idr.h> #include <linux/cdev.h> #include <linux/fs.h> #include <linux/uaccess.h> #include <linux/compat.h> +#include <linux/anon_inodes.h> +#include <linux/kfifo.h> +#include <linux/poll.h> +#include <linux/timekeeping.h> #include <uapi/linux/gpio.h> #include "gpiolib.h" @@ -310,6 +313,497 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc) return 0; } +/* + * 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 + * @numdescs: 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 numdescs; +}; + +static long linehandle_ioctl(struct file *filep, unsigned int cmd, + unsigned long arg) +{ + struct linehandle_state *lh = filep->private_data; + void __user *ip = (void __user *)arg; + struct gpiohandle_data ghd; + int i; + + if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { + int val; + + /* TODO: check if descriptors are really input */ + for (i = 0; i < lh->numdescs; i++) { + val = gpiod_get_value_cansleep(lh->descs[i]); + if (val < 0) + return val; + ghd.values[i] = val; + } + + if (copy_to_user(ip, &ghd, sizeof(ghd))) + return -EFAULT; + + return 0; + } else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) { + int vals[GPIOHANDLES_MAX]; + + /* TODO: check if descriptors are really output */ + if (copy_from_user(&ghd, ip, sizeof(ghd))) + return -EFAULT; + + /* Clamp all values to [0,1] */ + for (i = 0; i < lh->numdescs; i++) + vals[i] = !!ghd.values[i]; + + /* Reuse the array setting function */ + gpiod_set_array_value_complex(false, + true, + lh->numdescs, + lh->descs, + vals); + return 0; + } + return -EINVAL; +} + +#ifdef CONFIG_COMPAT +static long linehandle_ioctl_compat(struct file *filep, unsigned int cmd, + unsigned long arg) +{ + return linehandle_ioctl(filep, cmd, (unsigned long)compat_ptr(arg)); +} +#endif + +static int linehandle_release(struct inode *inode, struct file *filep) +{ + struct linehandle_state *lh = filep->private_data; + struct gpio_device *gdev = lh->gdev; + int i; + + for (i = 0; i < lh->numdescs; i++) + gpiod_free(lh->descs[i]); + kfree(lh->label); + kfree(lh); + put_device(&gdev->dev); + 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; + int fd, i, ret; + + if (copy_from_user(&handlereq, ip, sizeof(handlereq))) + return -EFAULT; + if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) + return -EINVAL; + + 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; + } + } + + /* Request each GPIO */ + for (i = 0; i < handlereq.lines; i++) { + u32 offset = handlereq.lineoffsets[i]; + u32 lflags = handlereq.flags; + struct gpio_desc *desc; + + desc = &gdev->descs[offset]; + ret = gpiod_request(desc, lh->label); + if (ret) + goto out_free_descs; + lh->descs[i] = desc; + + if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW) + set_bit(FLAG_ACTIVE_LOW, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) + set_bit(FLAG_OPEN_DRAIN, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE) + set_bit(FLAG_OPEN_SOURCE, &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 = !!handlereq.default_values[i]; + + ret = gpiod_direction_output(desc, val); + if (ret) + goto out_free_descs; + } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { + ret = gpiod_direction_input(desc); + if (ret) + goto out_free_descs; + } + dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", + offset); + } + /* Let i point at the last handle */ + i--; + lh->numdescs = handlereq.lines; + + fd = anon_inode_getfd("gpio-linehandle", + &linehandle_fileops, + lh, + O_RDONLY | O_CLOEXEC); + if (fd < 0) { + ret = fd; + goto out_free_descs; + } + + handlereq.fd = fd; + if (copy_to_user(ip, &handlereq, sizeof(handlereq))) { + ret = -EFAULT; + goto out_free_descs; + } + + dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", + lh->numdescs); + + return 0; + +out_free_descs: + for (; i >= 0; i--) + gpiod_free(lh->descs[i]); + kfree(lh->label); +out_free_lh: + kfree(lh); + put_device(&gdev->dev); + 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 + * @read_lock: mutex lock to protect reads from colliding with adding + * new events to the FIFO + */ +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); + struct mutex read_lock; +}; + +static unsigned int lineevent_poll(struct file *filep, + struct poll_table_struct *wait) +{ + struct lineevent_state *le = filep->private_data; + unsigned int events = 0; + + poll_wait(filep, &le->wait, wait); + + if (!kfifo_is_empty(&le->events)) + events = POLLIN | POLLRDNORM; + + return events; +} + + +static ssize_t lineevent_read(struct file *filep, + char __user *buf, + size_t count, + loff_t *f_ps) +{ + struct lineevent_state *le = filep->private_data; + unsigned int copied; + int ret; + + if (count < sizeof(struct gpioevent_data)) + return -EINVAL; + + do { + if (kfifo_is_empty(&le->events)) { + if (filep->f_flags & O_NONBLOCK) + return -EAGAIN; + + ret = wait_event_interruptible(le->wait, + !kfifo_is_empty(&le->events)); + if (ret) + return ret; + } + + if (mutex_lock_interruptible(&le->read_lock)) + return -ERESTARTSYS; + ret = kfifo_to_user(&le->events, buf, count, &copied); + mutex_unlock(&le->read_lock); + + if (ret) + return ret; + + /* + * If we couldn't read anything from the fifo (a different + * thread might have been faster) we either return -EAGAIN if + * the file descriptor is non-blocking, otherwise we go back to + * sleep and wait for more data to arrive. + */ + if (copied == 0 && (filep->f_flags & O_NONBLOCK)) + return -EAGAIN; + + } while (copied == 0); + + return copied; +} + +static int lineevent_release(struct inode *inode, struct file *filep) +{ + struct lineevent_state *le = filep->private_data; + struct gpio_device *gdev = le->gdev; + + free_irq(le->irq, le); + gpiod_free(le->desc); + kfree(le->label); + kfree(le); + put_device(&gdev->dev); + return 0; +} + +static long lineevent_ioctl(struct file *filep, unsigned int cmd, + unsigned long arg) +{ + struct lineevent_state *le = filep->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; + + 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 *filep, unsigned int cmd, + unsigned long arg) +{ + return lineevent_ioctl(filep, 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; + + ge.timestamp = ktime_get_real_ns(); + + if (le->eflags & GPIOEVENT_REQUEST_BOTH_EDGES) { + 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_put(&le->events, ge); + if (ret != 0) + wake_up_poll(&le->wait, POLLIN); + + return IRQ_HANDLED; +} + +static int lineevent_create(struct gpio_device *gdev, void __user *ip) +{ + struct gpioevent_request eventreq; + struct lineevent_state *le; + struct gpio_desc *desc; + u32 offset; + u32 lflags; + u32 eflags; + int fd; + int ret; + int irqflags = 0; + + if (copy_from_user(&eventreq, ip, sizeof(eventreq))) + return -EFAULT; + + 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; + } + } + + offset = eventreq.lineoffset; + lflags = eventreq.handleflags; + eflags = eventreq.eventflags; + + /* This is just wrong: we don't look for events on output lines */ + if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { + ret = -EINVAL; + goto out_free_label; + } + + desc = &gdev->descs[offset]; + ret = gpiod_request(desc, le->label); + if (ret) + goto out_free_desc; + le->desc = desc; + le->eflags = eflags; + + if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW) + set_bit(FLAG_ACTIVE_LOW, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) + set_bit(FLAG_OPEN_DRAIN, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE) + set_bit(FLAG_OPEN_SOURCE, &desc->flags); + + ret = gpiod_direction_input(desc); + if (ret) + goto out_free_desc; + + le->irq = gpiod_to_irq(desc); + if (le->irq <= 0) { + ret = -ENODEV; + goto out_free_desc; + } + + if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) + irqflags |= IRQF_TRIGGER_RISING; + if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) + irqflags |= IRQF_TRIGGER_FALLING; + irqflags |= IRQF_ONESHOT; + irqflags |= IRQF_SHARED; + + INIT_KFIFO(le->events); + init_waitqueue_head(&le->wait); + mutex_init(&le->read_lock); + + /* Request a thread to read the events */ + ret = request_threaded_irq(le->irq, + NULL, + lineevent_irq_thread, + irqflags, + le->label, + le); + if (ret) + goto out_free_desc; + + fd = anon_inode_getfd("gpio-event", + &lineevent_fileops, + le, + O_RDONLY | O_CLOEXEC); + if (fd < 0) { + ret = fd; + goto out_free_irq; + } + + eventreq.fd = fd; + if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { + ret = -EFAULT; + goto out_free_irq; + } + + return 0; + +out_free_irq: + free_irq(le->irq, le); +out_free_desc: + gpiod_free(le->desc); +out_free_label: + kfree(le->label); +out_free_le: + kfree(le); + put_device(&gdev->dev); + return ret; +} + /** * gpio_ioctl() - ioctl handler for the GPIO chardev */ @@ -385,6 +879,10 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 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); } return -EINVAL; } @@ -449,7 +947,6 @@ static void gpiodevice_release(struct device *dev) { struct gpio_device *gdev = dev_get_drvdata(dev); - cdev_del(&gdev->chrdev); list_del(&gdev->list); ida_simple_remove(&gpio_ida, gdev->id); kfree(gdev->label); @@ -482,7 +979,6 @@ static int gpiochip_setup_dev(struct gpio_device *gdev) /* From this point, the .release() function cleans up gpio_device */ gdev->dev.release = gpiodevice_release; - get_device(&gdev->dev); pr_debug("%s: registered GPIOs %d to %d on device: %s (%s)\n", __func__, gdev->base, gdev->base + gdev->ngpio - 1, dev_name(&gdev->dev), gdev->chip->label ? : "generic"); @@ -550,13 +1046,14 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data) if (chip->parent) { gdev->dev.parent = chip->parent; gdev->dev.of_node = chip->parent->of_node; - } else { + } + #ifdef CONFIG_OF_GPIO /* If the gpiochip has an assigned OF node this takes precedence */ - if (chip->of_node) - gdev->dev.of_node = chip->of_node; + if (chip->of_node) + gdev->dev.of_node = chip->of_node; #endif - } + gdev->id = ida_simple_get(&gpio_ida, 0, 0, GFP_KERNEL); if (gdev->id < 0) { status = gdev->id; @@ -770,6 +1267,8 @@ void gpiochip_remove(struct gpio_chip *chip) * be removed, else it will be dangling until the last user is * gone. */ + cdev_del(&gdev->chrdev); + device_del(&gdev->dev); put_device(&gdev->dev); } EXPORT_SYMBOL_GPL(gpiochip_remove); @@ -869,7 +1368,7 @@ struct gpio_chip *gpiochip_find(void *data, spin_lock_irqsave(&gpio_lock, flags); list_for_each_entry(gdev, &gpio_devices, list) - if (match(gdev->chip, data)) + if (gdev->chip && match(gdev->chip, data)) break; /* No match? */ @@ -1352,14 +1851,6 @@ static int __gpiod_request(struct gpio_desc *desc, const char *label) spin_lock_irqsave(&gpio_lock, flags); } done: - if (status < 0) { - /* Clear flags that might have been set by the caller before - * requesting the GPIO. - */ - clear_bit(FLAG_ACTIVE_LOW, &desc->flags); - clear_bit(FLAG_OPEN_DRAIN, &desc->flags); - clear_bit(FLAG_OPEN_SOURCE, &desc->flags); - } spin_unlock_irqrestore(&gpio_lock, flags); return status; } @@ -1373,8 +1864,12 @@ done: #define VALIDATE_DESC(desc) do { \ if (!desc) \ return 0; \ + if (IS_ERR(desc)) { \ + pr_warn("%s: invalid GPIO (errorpointer)\n", __func__); \ + return PTR_ERR(desc); \ + } \ if (!desc->gdev) { \ - pr_warn("%s: invalid GPIO\n", __func__); \ + pr_warn("%s: invalid GPIO (no device)\n", __func__); \ return -EINVAL; \ } \ if ( !desc->gdev->chip ) { \ @@ -1386,8 +1881,12 @@ done: #define VALIDATE_DESC_VOID(desc) do { \ if (!desc) \ return; \ + if (IS_ERR(desc)) { \ + pr_warn("%s: invalid GPIO (errorpointer)\n", __func__); \ + return; \ + } \ if (!desc->gdev) { \ - pr_warn("%s: invalid GPIO\n", __func__); \ + pr_warn("%s: invalid GPIO (no device)\n", __func__); \ return; \ } \ if (!desc->gdev->chip) { \ @@ -2056,7 +2555,14 @@ int gpiod_to_irq(const struct gpio_desc *desc) struct gpio_chip *chip; int offset; - VALIDATE_DESC(desc); + /* + * Cannot VALIDATE_DESC() here as gpiod_to_irq() consumer semantics + * requires this function to not return zero on an invalid descriptor + * but rather a negative error number. + */ + if (!desc || IS_ERR(desc) || !desc->gdev || !desc->gdev->chip) + return -EINVAL; + chip = desc->gdev->chip; offset = gpio_chip_hwgpio(desc); if (chip->to_irq) { @@ -2326,7 +2832,7 @@ static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx, &of_flags); - if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER)) + if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT)) break; } @@ -2572,28 +3078,13 @@ struct gpio_desc *__must_check gpiod_get_optional(struct device *dev, } EXPORT_SYMBOL_GPL(gpiod_get_optional); -/** - * gpiod_parse_flags - helper function to parse GPIO lookup flags - * @desc: gpio to be setup - * @lflags: gpio_lookup_flags - returned from of_find_gpio() or - * of_get_gpio_hog() - * - * Set the GPIO descriptor flags based on the given GPIO lookup flags. - */ -static void gpiod_parse_flags(struct gpio_desc *desc, unsigned long lflags) -{ - if (lflags & GPIO_ACTIVE_LOW) - set_bit(FLAG_ACTIVE_LOW, &desc->flags); - if (lflags & GPIO_OPEN_DRAIN) - set_bit(FLAG_OPEN_DRAIN, &desc->flags); - if (lflags & GPIO_OPEN_SOURCE) - set_bit(FLAG_OPEN_SOURCE, &desc->flags); -} /** * gpiod_configure_flags - helper function to configure a given GPIO * @desc: gpio whose value will be assigned * @con_id: function within the GPIO consumer + * @lflags: gpio_lookup_flags - returned from of_find_gpio() or + * of_get_gpio_hog() * @dflags: gpiod_flags - optional GPIO initialization flags * * Return 0 on success, -ENOENT if no GPIO has been assigned to the @@ -2601,10 +3092,17 @@ static void gpiod_parse_flags(struct gpio_desc *desc, unsigned long lflags) * occurred while trying to acquire the GPIO. */ static int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id, - enum gpiod_flags dflags) + unsigned long lflags, enum gpiod_flags dflags) { int status; + if (lflags & GPIO_ACTIVE_LOW) + set_bit(FLAG_ACTIVE_LOW, &desc->flags); + if (lflags & GPIO_OPEN_DRAIN) + set_bit(FLAG_OPEN_DRAIN, &desc->flags); + if (lflags & GPIO_OPEN_SOURCE) + set_bit(FLAG_OPEN_SOURCE, &desc->flags); + /* No particular flag request, return here... */ if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) { pr_debug("no flags found for %s\n", con_id); @@ -2671,13 +3169,11 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev, return desc; } - gpiod_parse_flags(desc, lookupflags); - status = gpiod_request(desc, con_id); if (status < 0) return ERR_PTR(status); - status = gpiod_configure_flags(desc, con_id, flags); + status = gpiod_configure_flags(desc, con_id, lookupflags, flags); if (status < 0) { dev_dbg(dev, "setup of GPIO %s failed\n", con_id); gpiod_put(desc); @@ -2733,6 +3229,10 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode, if (IS_ERR(desc)) return desc; + ret = gpiod_request(desc, NULL); + if (ret) + return ERR_PTR(ret); + if (active_low) set_bit(FLAG_ACTIVE_LOW, &desc->flags); @@ -2743,10 +3243,6 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode, set_bit(FLAG_OPEN_SOURCE, &desc->flags); } - ret = gpiod_request(desc, NULL); - if (ret) - return ERR_PTR(ret); - return desc; } EXPORT_SYMBOL_GPL(fwnode_get_named_gpiod); @@ -2799,8 +3295,6 @@ int gpiod_hog(struct gpio_desc *desc, const char *name, chip = gpiod_to_chip(desc); hwnum = gpio_chip_hwgpio(desc); - gpiod_parse_flags(desc, lflags); - local_desc = gpiochip_request_own_desc(chip, hwnum, name); if (IS_ERR(local_desc)) { status = PTR_ERR(local_desc); @@ -2809,7 +3303,7 @@ int gpiod_hog(struct gpio_desc *desc, const char *name, return status; } - status = gpiod_configure_flags(desc, name, dflags); + status = gpiod_configure_flags(desc, name, lflags, dflags); if (status < 0) { pr_err("setup of hog GPIO %s (chip %s, offset %d) failed, %d\n", name, chip->label, hwnum, status); |