#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/gpio.h>
+#include <linux/idr.h>
/* Optional implementation infrastructure for GPIO interfaces.
#define FLAG_RESERVED 2
#define FLAG_EXPORT 3 /* protected by sysfs_lock */
#define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */
+#define FLAG_TRIG_FALL 5 /* trigger on falling edge */
+#define FLAG_TRIG_RISE 6 /* trigger on rising edge */
+
+#define PDESC_ID_SHIFT 16 /* add new flags before this one */
+
+#define GPIO_FLAGS_MASK ((1 << PDESC_ID_SHIFT) - 1)
+#define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
#ifdef CONFIG_DEBUG_FS
const char *label;
};
static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
+#ifdef CONFIG_GPIO_SYSFS
+struct poll_desc {
+ struct work_struct work;
+ struct sysfs_dirent *value_sd;
+};
+
+static struct idr pdesc_idr;
+#endif
+
static inline void desc_set_label(struct gpio_desc *d, const char *label)
{
#ifdef CONFIG_DEBUG_FS
* when setting direction, and otherwise illegal. Until board setup code
* and drivers use explicit requests everywhere (which won't happen when
* those calls have no teeth) we can't avoid autorequesting. This nag
- * message should motivate switching to explicit requests...
+ * message should motivate switching to explicit requests... so should
+ * the weaker cleanup after faults, compared to gpio_request().
+ *
+ * NOTE: the autorequest mechanism is going away; at this point it's
+ * only "legal" in the sense that (old) code using it won't break yet,
+ * but instead only triggers a WARN() stack dump.
*/
-static void gpio_ensure_requested(struct gpio_desc *desc)
+static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset)
{
- if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
- pr_warning("GPIO-%d autorequested\n", (int)(desc - gpio_desc));
+ const struct gpio_chip *chip = desc->chip;
+ const int gpio = chip->base + offset;
+
+ if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
+ "autorequest GPIO-%d\n", gpio)) {
+ if (!try_module_get(chip->owner)) {
+ pr_err("GPIO-%d: module can't be gotten \n", gpio);
+ clear_bit(FLAG_REQUESTED, &desc->flags);
+ /* lose */
+ return -EIO;
+ }
desc_set_label(desc, "[auto]");
- if (!try_module_get(desc->chip->owner))
- pr_err("GPIO-%d: module can't be gotten \n",
- (int)(desc - gpio_desc));
+ /* caller must chip->request() w/o spinlock */
+ if (chip->request)
+ return 1;
}
+ return 0;
}
/* caller holds gpio_lock *OR* gpio is marked as requested */
* /value
* * always readable, subject to hardware behavior
* * may be writable, as zero/nonzero
- *
- * REVISIT there will likely be an attribute for configuring async
- * notifications, e.g. to specify polling interval or IRQ trigger type
- * that would for example trigger a poll() on the "value".
+ * /edge
+ * * configures behavior of poll(2) on /value
+ * * available only if pin can generate IRQs on input
+ * * is read/write as "none", "falling", "rising", or "both"
*/
static ssize_t gpio_direction_show(struct device *dev,
if (!test_bit(FLAG_EXPORT, &desc->flags))
status = -EIO;
else
- status = sprintf(buf, "%d\n", gpio_get_value_cansleep(gpio));
+ status = sprintf(buf, "%d\n", !!gpio_get_value_cansleep(gpio));
mutex_unlock(&sysfs_lock);
return status;
static /*const*/ DEVICE_ATTR(value, 0644,
gpio_value_show, gpio_value_store);
+static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
+{
+ struct work_struct *work = priv;
+
+ schedule_work(work);
+ return IRQ_HANDLED;
+}
+
+static void gpio_notify_sysfs(struct work_struct *work)
+{
+ struct poll_desc *pdesc;
+
+ pdesc = container_of(work, struct poll_desc, work);
+ sysfs_notify_dirent(pdesc->value_sd);
+}
+
+static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
+ unsigned long gpio_flags)
+{
+ struct poll_desc *pdesc;
+ unsigned long irq_flags;
+ int ret, irq, id;
+
+ if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
+ return 0;
+
+ irq = gpio_to_irq(desc - gpio_desc);
+ if (irq < 0)
+ return -EIO;
+
+ id = desc->flags >> PDESC_ID_SHIFT;
+ pdesc = idr_find(&pdesc_idr, id);
+ if (pdesc) {
+ free_irq(irq, &pdesc->work);
+ cancel_work_sync(&pdesc->work);
+ }
+
+ desc->flags &= ~GPIO_TRIGGER_MASK;
+
+ if (!gpio_flags) {
+ ret = 0;
+ goto free_sd;
+ }
+
+ irq_flags = IRQF_SHARED;
+ if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
+ irq_flags |= IRQF_TRIGGER_FALLING;
+ if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
+ irq_flags |= IRQF_TRIGGER_RISING;
+
+ if (!pdesc) {
+ pdesc = kmalloc(sizeof(*pdesc), GFP_KERNEL);
+ if (!pdesc) {
+ ret = -ENOMEM;
+ goto err_out;
+ }
+
+ do {
+ ret = -ENOMEM;
+ if (idr_pre_get(&pdesc_idr, GFP_KERNEL))
+ ret = idr_get_new_above(&pdesc_idr,
+ pdesc, 1, &id);
+ } while (ret == -EAGAIN);
+
+ if (ret)
+ goto free_mem;
+
+ desc->flags &= GPIO_FLAGS_MASK;
+ desc->flags |= (unsigned long)id << PDESC_ID_SHIFT;
+
+ if (desc->flags >> PDESC_ID_SHIFT != id) {
+ ret = -ERANGE;
+ goto free_id;
+ }
+
+ pdesc->value_sd = sysfs_get_dirent(dev->kobj.sd, "value");
+ if (!pdesc->value_sd) {
+ ret = -ENODEV;
+ goto free_id;
+ }
+ INIT_WORK(&pdesc->work, gpio_notify_sysfs);
+ }
+
+ ret = request_irq(irq, gpio_sysfs_irq, irq_flags,
+ "gpiolib", &pdesc->work);
+ if (ret)
+ goto free_sd;
+
+ desc->flags |= gpio_flags;
+ return 0;
+
+free_sd:
+ sysfs_put(pdesc->value_sd);
+free_id:
+ idr_remove(&pdesc_idr, id);
+ desc->flags &= GPIO_FLAGS_MASK;
+free_mem:
+ kfree(pdesc);
+err_out:
+ return ret;
+}
+
+static const struct {
+ const char *name;
+ unsigned long flags;
+} trigger_types[] = {
+ { "none", 0 },
+ { "falling", BIT(FLAG_TRIG_FALL) },
+ { "rising", BIT(FLAG_TRIG_RISE) },
+ { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
+};
+
+static ssize_t gpio_edge_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else {
+ int i;
+
+ status = 0;
+ for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
+ if ((desc->flags & GPIO_TRIGGER_MASK)
+ == trigger_types[i].flags) {
+ status = sprintf(buf, "%s\n",
+ trigger_types[i].name);
+ break;
+ }
+ }
+
+ mutex_unlock(&sysfs_lock);
+ return status;
+}
+
+static ssize_t gpio_edge_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
+ if (sysfs_streq(trigger_types[i].name, buf))
+ goto found;
+ return -EINVAL;
+
+found:
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else {
+ status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
+ if (!status)
+ status = size;
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+ return status;
+}
+
+static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
+
static const struct attribute *gpio_attrs[] = {
&dev_attr_direction.attr,
&dev_attr_value.attr,
unsigned long flags;
struct gpio_desc *desc;
int status = -EINVAL;
+ char *ioname = NULL;
/* can't export until sysfs is available ... */
if (!gpio_class.p) {
}
spin_unlock_irqrestore(&gpio_lock, flags);
+ if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
+ ioname = desc->chip->names[gpio - desc->chip->base];
+
if (status == 0) {
struct device *dev;
dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
- desc, "gpio%d", gpio);
+ desc, ioname ? ioname : "gpio%d", gpio);
if (dev) {
if (direction_may_change)
status = sysfs_create_group(&dev->kobj,
else
status = device_create_file(dev,
&dev_attr_value);
+
+ if (!status && gpio_to_irq(gpio) >= 0
+ && (direction_may_change
+ || !test_bit(FLAG_IS_OUT,
+ &desc->flags)))
+ status = device_create_file(dev,
+ &dev_attr_edge);
+
if (status != 0)
device_unregister(dev);
} else
return dev_get_drvdata(dev) == data;
}
+/**
+ * gpio_export_link - create a sysfs link to an exported GPIO node
+ * @dev: device under which to create symlink
+ * @name: name of the symlink
+ * @gpio: gpio to create symlink to, already exported
+ *
+ * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
+ * node. Caller is responsible for unlinking.
+ *
+ * Returns zero on success, else an error.
+ */
+int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
+{
+ struct gpio_desc *desc;
+ int status = -EINVAL;
+
+ if (!gpio_is_valid(gpio))
+ goto done;
+
+ mutex_lock(&sysfs_lock);
+
+ desc = &gpio_desc[gpio];
+
+ if (test_bit(FLAG_EXPORT, &desc->flags)) {
+ struct device *tdev;
+
+ tdev = class_find_device(&gpio_class, NULL, desc, match_export);
+ if (tdev != NULL) {
+ status = sysfs_create_link(&dev->kobj, &tdev->kobj,
+ name);
+ } else {
+ status = -ENODEV;
+ }
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+done:
+ if (status)
+ pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_export_link);
+
/**
* gpio_unexport - reverse effect of gpio_export()
* @gpio: gpio to make unavailable
mutex_lock(&sysfs_lock);
desc = &gpio_desc[gpio];
+
if (test_bit(FLAG_EXPORT, &desc->flags)) {
struct device *dev = NULL;
dev = class_find_device(&gpio_class, NULL, desc, match_export);
if (dev) {
+ gpio_setup_irq(desc, dev, 0);
clear_bit(FLAG_EXPORT, &desc->flags);
put_device(dev);
device_unregister(dev);
unsigned long flags;
unsigned gpio;
+ idr_init(&pdesc_idr);
+
status = class_register(&gpio_class);
if (status < 0)
return status;
int gpio_request(unsigned gpio, const char *label)
{
struct gpio_desc *desc;
+ struct gpio_chip *chip;
int status = -EINVAL;
unsigned long flags;
if (!gpio_is_valid(gpio))
goto done;
desc = &gpio_desc[gpio];
- if (desc->chip == NULL)
+ chip = desc->chip;
+ if (chip == NULL)
goto done;
- if (!try_module_get(desc->chip->owner))
+ if (!try_module_get(chip->owner))
goto done;
/* NOTE: gpio_request() can be called in early boot,
- * before IRQs are enabled.
+ * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
*/
if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
status = 0;
} else {
status = -EBUSY;
- module_put(desc->chip->owner);
+ module_put(chip->owner);
+ goto done;
+ }
+
+ if (chip->request) {
+ /* chip->request may sleep */
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ status = chip->request(chip, gpio - chip->base);
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (status < 0) {
+ desc_set_label(desc, NULL);
+ module_put(chip->owner);
+ clear_bit(FLAG_REQUESTED, &desc->flags);
+ }
}
done:
{
unsigned long flags;
struct gpio_desc *desc;
+ struct gpio_chip *chip;
might_sleep();
spin_lock_irqsave(&gpio_lock, flags);
desc = &gpio_desc[gpio];
- if (desc->chip && test_and_clear_bit(FLAG_REQUESTED, &desc->flags)) {
+ chip = desc->chip;
+ if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
+ if (chip->free) {
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ might_sleep_if(extra_checks && chip->can_sleep);
+ chip->free(chip, gpio - chip->base);
+ spin_lock_irqsave(&gpio_lock, flags);
+ }
desc_set_label(desc, NULL);
module_put(desc->chip->owner);
+ clear_bit(FLAG_REQUESTED, &desc->flags);
} else
WARN_ON(extra_checks);
gpio -= chip->base;
if (gpio >= chip->ngpio)
goto fail;
- gpio_ensure_requested(desc);
+ status = gpio_ensure_requested(desc, gpio);
+ if (status < 0)
+ goto fail;
/* now we know the gpio is valid and chip won't vanish */
might_sleep_if(extra_checks && chip->can_sleep);
+ if (status) {
+ status = chip->request(chip, gpio);
+ if (status < 0) {
+ pr_debug("GPIO-%d: chip request fail, %d\n",
+ chip->base + gpio, status);
+ /* and it's not available to anyone else ...
+ * gpio_request() is the fully clean solution.
+ */
+ goto lose;
+ }
+ }
+
status = chip->direction_input(chip, gpio);
if (status == 0)
clear_bit(FLAG_IS_OUT, &desc->flags);
+lose:
return status;
fail:
spin_unlock_irqrestore(&gpio_lock, flags);
gpio -= chip->base;
if (gpio >= chip->ngpio)
goto fail;
- gpio_ensure_requested(desc);
+ status = gpio_ensure_requested(desc, gpio);
+ if (status < 0)
+ goto fail;
/* now we know the gpio is valid and chip won't vanish */
might_sleep_if(extra_checks && chip->can_sleep);
+ if (status) {
+ status = chip->request(chip, gpio);
+ if (status < 0) {
+ pr_debug("GPIO-%d: chip request fail, %d\n",
+ chip->base + gpio, status);
+ /* and it's not available to anyone else ...
+ * gpio_request() is the fully clean solution.
+ */
+ goto lose;
+ }
+ }
+
status = chip->direction_output(chip, gpio, value);
if (status == 0)
set_bit(FLAG_IS_OUT, &desc->flags);
+lose:
return status;
fail:
spin_unlock_irqrestore(&gpio_lock, flags);
might_sleep_if(extra_checks);
chip = gpio_to_chip(gpio);
- return chip->get(chip, gpio - chip->base);
+ return chip->get ? chip->get(chip, gpio - chip->base) : 0;
}
EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
continue;
is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
- seq_printf(s, " gpio-%-3d (%-12s) %s %s",
+ seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
gpio, gdesc->label,
is_out ? "out" : "in ",
chip->get
if (!is_out) {
int irq = gpio_to_irq(gpio);
- struct irq_desc *desc = irq_desc + irq;
+ struct irq_desc *desc = irq_to_desc(irq);
/* This races with request_irq(), set_irq_type(),
* and set_irq_wake() ... but those are "rare".
if (dev)
seq_printf(s, ", %s/%s",
dev->bus ? dev->bus->name : "no-bus",
- dev->bus_id);
+ dev_name(dev));
if (chip->label)
seq_printf(s, ", %s", chip->label);
if (chip->can_sleep)
Code Review / linux-2.6.git / blobdiff