#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>
+#include <linux/slab.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 FLAG_ACTIVE_LOW 7 /* sysfs value has active low */
+
+#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
* /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"
+ * /active_low
+ * * configures polarity of /value
+ * * is read/write as zero/nonzero
+ * * also affects existing and subsequent "falling" and "rising"
+ * /edge configuration
*/
static ssize_t gpio_direction_show(struct device *dev,
return status ? : size;
}
-static const DEVICE_ATTR(direction, 0644,
+static /* const */ DEVICE_ATTR(direction, 0644,
gpio_direction_show, gpio_direction_store);
static ssize_t gpio_value_show(struct device *dev,
mutex_lock(&sysfs_lock);
- if (!test_bit(FLAG_EXPORT, &desc->flags))
+ if (!test_bit(FLAG_EXPORT, &desc->flags)) {
status = -EIO;
- else
- status = sprintf(buf, "%d\n", !!gpio_get_value_cansleep(gpio));
+ } else {
+ int value;
+
+ value = !!gpio_get_value_cansleep(gpio);
+ if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+ value = !value;
+
+ status = sprintf(buf, "%d\n", value);
+ }
mutex_unlock(&sysfs_lock);
return status;
status = strict_strtol(buf, 0, &value);
if (status == 0) {
+ if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+ value = !value;
gpio_set_value_cansleep(gpio, value != 0);
status = size;
}
return status;
}
-static /*const*/ DEVICE_ATTR(value, 0644,
+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 |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+ IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
+ if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
+ irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+ IRQF_TRIGGER_FALLING : 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, NULL, "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:
+ if (pdesc)
+ 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 int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
+ int value)
+{
+ int status = 0;
+
+ if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
+ return 0;
+
+ if (value)
+ set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+ else
+ clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
+
+ /* reconfigure poll(2) support if enabled on one edge only */
+ if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
+ !!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
+ unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
+
+ gpio_setup_irq(desc, dev, 0);
+ status = gpio_setup_irq(desc, dev, trigger_flags);
+ }
+
+ return status;
+}
+
+static ssize_t gpio_active_low_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
+ status = sprintf(buf, "%d\n",
+ !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
+
+ mutex_unlock(&sysfs_lock);
+
+ return status;
+}
+
+static ssize_t gpio_active_low_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;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags)) {
+ status = -EIO;
+ } else {
+ long value;
+
+ status = strict_strtol(buf, 0, &value);
+ if (status == 0)
+ status = sysfs_set_active_low(desc, dev, value != 0);
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+ return status ? : size;
+}
+
+static const DEVICE_ATTR(active_low, 0644,
+ gpio_active_low_show, gpio_active_low_store);
+
static const struct attribute *gpio_attrs[] = {
- &dev_attr_direction.attr,
&dev_attr_value.attr,
+ &dev_attr_active_low.attr,
NULL,
};
* /sys/class/gpio/unexport ... write-only
* integer N ... number of GPIO to unexport
*/
-static ssize_t export_store(struct class *class, const char *buf, size_t len)
+static ssize_t export_store(struct class *class,
+ struct class_attribute *attr,
+ const char *buf, size_t len)
{
long gpio;
int status;
return status ? : len;
}
-static ssize_t unexport_store(struct class *class, const char *buf, size_t len)
+static ssize_t unexport_store(struct class *class,
+ struct class_attribute *attr,
+ const char *buf, size_t len)
{
long gpio;
int status;
unsigned long flags;
struct gpio_desc *desc;
int status = -EINVAL;
- char *ioname = NULL;
+ const char *ioname = NULL;
/* can't export until sysfs is available ... */
if (!gpio_class.p) {
struct device *dev;
dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
- desc, ioname ? ioname : "gpio%d", gpio);
- if (dev) {
- if (direction_may_change)
- status = sysfs_create_group(&dev->kobj,
+ desc, ioname ? ioname : "gpio%u", gpio);
+ if (!IS_ERR(dev)) {
+ status = sysfs_create_group(&dev->kobj,
&gpio_attr_group);
- else
+
+ if (!status && direction_may_change)
+ status = device_create_file(dev,
+ &dev_attr_direction);
+
+ if (!status && gpio_to_irq(gpio) >= 0
+ && (direction_may_change
+ || !test_bit(FLAG_IS_OUT,
+ &desc->flags)))
status = device_create_file(dev,
- &dev_attr_value);
+ &dev_attr_edge);
+
if (status != 0)
device_unregister(dev);
} else
- status = -ENODEV;
+ status = PTR_ERR(dev);
if (status == 0)
set_bit(FLAG_EXPORT, &desc->flags);
}
}
EXPORT_SYMBOL_GPL(gpio_export_link);
+
+/**
+ * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
+ * @gpio: gpio to change
+ * @value: non-zero to use active low, i.e. inverted values
+ *
+ * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
+ * The GPIO does not have to be exported yet. If poll(2) support has
+ * been enabled for either rising or falling edge, it will be
+ * reconfigured to follow the new polarity.
+ *
+ * Returns zero on success, else an error.
+ */
+int gpio_sysfs_set_active_low(unsigned gpio, int value)
+{
+ struct gpio_desc *desc;
+ struct device *dev = NULL;
+ 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)) {
+ dev = class_find_device(&gpio_class, NULL, desc, match_export);
+ if (dev == NULL) {
+ status = -ENODEV;
+ goto unlock;
+ }
+ }
+
+ status = sysfs_set_active_low(desc, dev, value);
+
+unlock:
+ mutex_unlock(&sysfs_lock);
+
+done:
+ if (status)
+ pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);
+
/**
* gpio_unexport - reverse effect of gpio_export()
* @gpio: gpio to make unavailable
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);
mutex_lock(&sysfs_lock);
dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
"gpiochip%d", chip->base);
- if (dev) {
+ if (!IS_ERR(dev)) {
status = sysfs_create_group(&dev->kobj,
&gpiochip_attr_group);
} else
- status = -ENODEV;
+ status = PTR_ERR(dev);
chip->exported = (status == 0);
mutex_unlock(&sysfs_lock);
unsigned long flags;
unsigned gpio;
+ idr_init(&pdesc_idr);
+
status = class_register(&gpio_class);
if (status < 0)
return status;
fail:
/* failures here can mean systems won't boot... */
if (status)
- pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n",
+ pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
chip->base, chip->base + chip->ngpio - 1,
chip->label ? : "generic");
return status;
}
desc_set_label(desc, NULL);
module_put(desc->chip->owner);
+ clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
clear_bit(FLAG_REQUESTED, &desc->flags);
} else
WARN_ON(extra_checks);
}
EXPORT_SYMBOL_GPL(gpio_free);
+/**
+ * gpio_request_one - request a single GPIO with initial configuration
+ * @gpio: the GPIO number
+ * @flags: GPIO configuration as specified by GPIOF_*
+ * @label: a literal description string of this GPIO
+ */
+int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
+{
+ int err;
+
+ err = gpio_request(gpio, label);
+ if (err)
+ return err;
+
+ if (flags & GPIOF_DIR_IN)
+ err = gpio_direction_input(gpio);
+ else
+ err = gpio_direction_output(gpio,
+ (flags & GPIOF_INIT_HIGH) ? 1 : 0);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(gpio_request_one);
+
+/**
+ * gpio_request_array - request multiple GPIOs in a single call
+ * @array: array of the 'struct gpio'
+ * @num: how many GPIOs in the array
+ */
+int gpio_request_array(struct gpio *array, size_t num)
+{
+ int i, err;
+
+ for (i = 0; i < num; i++, array++) {
+ err = gpio_request_one(array->gpio, array->flags, array->label);
+ if (err)
+ goto err_free;
+ }
+ return 0;
+
+err_free:
+ while (i--)
+ gpio_free((--array)->gpio);
+ return err;
+}
+EXPORT_SYMBOL_GPL(gpio_request_array);
+
+/**
+ * gpio_free_array - release multiple GPIOs in a single call
+ * @array: array of the 'struct gpio'
+ * @num: how many GPIOs in the array
+ */
+void gpio_free_array(struct gpio *array, size_t num)
+{
+ while (num--)
+ gpio_free((array++)->gpio);
+}
+EXPORT_SYMBOL_GPL(gpio_free_array);
/**
* gpiochip_is_requested - return string iff signal was requested
}
EXPORT_SYMBOL_GPL(gpio_direction_output);
+/**
+ * gpio_set_debounce - sets @debounce time for a @gpio
+ * @gpio: the gpio to set debounce time
+ * @debounce: debounce time is microseconds
+ */
+int gpio_set_debounce(unsigned gpio, unsigned debounce)
+{
+ unsigned long flags;
+ struct gpio_chip *chip;
+ struct gpio_desc *desc = &gpio_desc[gpio];
+ int status = -EINVAL;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (!gpio_is_valid(gpio))
+ goto fail;
+ chip = desc->chip;
+ if (!chip || !chip->set || !chip->set_debounce)
+ goto fail;
+ gpio -= chip->base;
+ if (gpio >= chip->ngpio)
+ goto fail;
+ status = gpio_ensure_requested(desc, gpio);
+ if (status < 0)
+ goto fail;
+
+ /* now we know the gpio is valid and chip won't vanish */
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ might_sleep_if(extra_checks && chip->can_sleep);
+
+ return chip->set_debounce(chip, gpio, debounce);
+
+fail:
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ if (status)
+ pr_debug("%s: gpio-%d status %d\n",
+ __func__, gpio, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_set_debounce);
/* I/O calls are only valid after configuration completed; the relevant
* "is this a valid GPIO" error checks should already have been done.
return single_open(file, gpiolib_show, NULL);
}
-static struct file_operations gpiolib_operations = {
+static const struct file_operations gpiolib_operations = {
.open = gpiolib_open,
.read = seq_read,
.llseek = seq_lseek,
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff