X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=drivers%2Fgpio%2Fgpiolib.c;h=662ed923d9eb0be22a49c0a1db2ae5c14e11d49d;hp=572d372899d3ba79002e8a3aaeaf395633468d16;hb=828c09509b9695271bcbdc53e9fc9a6a737148d2;hpb=08678b0841267c1d00d771fe01548d86043d065e

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 572d3728..662ed92 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1,5 +1,6 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/spinlock.h>
 #include <linux/device.h>
@@ -7,6 +8,7 @@
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 #include <linux/gpio.h>
+#include <linux/idr.h>
 
 
 /* Optional implementation infrastructure for GPIO interfaces.
@@ -49,6 +51,13 @@ struct gpio_desc {
 #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;
@@ -56,6 +65,15 @@ struct gpio_desc {
 };
 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
@@ -67,17 +85,32 @@ static inline void desc_set_label(struct gpio_desc *d, const char *label)
  * 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 */
@@ -173,10 +206,10 @@ static DEFINE_MUTEX(sysfs_lock);
  *   /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,
@@ -237,7 +270,7 @@ static ssize_t gpio_value_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;
@@ -273,6 +306,175 @@ static ssize_t gpio_value_store(struct device *dev,
 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,
@@ -427,6 +629,7 @@ int gpio_export(unsigned gpio, bool direction_may_change)
 	unsigned long		flags;
 	struct gpio_desc	*desc;
 	int			status = -EINVAL;
+	char			*ioname = NULL;
 
 	/* can't export until sysfs is available ... */
 	if (!gpio_class.p) {
@@ -450,11 +653,14 @@ int gpio_export(unsigned gpio, bool direction_may_change)
 	}
 	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,
@@ -462,6 +668,14 @@ int gpio_export(unsigned gpio, bool direction_may_change)
 			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
@@ -486,6 +700,51 @@ static int match_export(struct device *dev, void *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
  *
@@ -502,11 +761,13 @@ void gpio_unexport(unsigned gpio)
 	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);
@@ -591,6 +852,8 @@ static int __init gpiolib_sysfs_init(void)
 	unsigned long	flags;
 	unsigned	gpio;
 
+	idr_init(&pdesc_idr);
+
 	status = class_register(&gpio_class);
 	if (status < 0)
 		return status;
@@ -752,6 +1015,7 @@ EXPORT_SYMBOL_GPL(gpiochip_remove);
 int gpio_request(unsigned gpio, const char *label)
 {
 	struct gpio_desc	*desc;
+	struct gpio_chip	*chip;
 	int			status = -EINVAL;
 	unsigned long		flags;
 
@@ -760,14 +1024,15 @@ int gpio_request(unsigned gpio, const char *label)
 	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) {
@@ -775,7 +1040,21 @@ int gpio_request(unsigned gpio, const char *label)
 		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:
@@ -791,6 +1070,9 @@ void gpio_free(unsigned gpio)
 {
 	unsigned long		flags;
 	struct gpio_desc	*desc;
+	struct gpio_chip	*chip;
+
+	might_sleep();
 
 	if (!gpio_is_valid(gpio)) {
 		WARN_ON(extra_checks);
@@ -802,9 +1084,17 @@ void gpio_free(unsigned gpio)
 	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);
 
@@ -869,7 +1159,9 @@ int gpio_direction_input(unsigned gpio)
 	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 */
 
@@ -877,9 +1169,22 @@ int gpio_direction_input(unsigned gpio)
 
 	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);
@@ -907,7 +1212,9 @@ int gpio_direction_output(unsigned gpio, int value)
 	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 */
 
@@ -915,9 +1222,22 @@ int gpio_direction_output(unsigned gpio, int value)
 
 	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);
@@ -1008,6 +1328,24 @@ int __gpio_cansleep(unsigned gpio)
 }
 EXPORT_SYMBOL_GPL(__gpio_cansleep);
 
+/**
+ * __gpio_to_irq() - return the IRQ corresponding to a GPIO
+ * @gpio: gpio whose IRQ will be returned (already requested)
+ * Context: any
+ *
+ * This is used directly or indirectly to implement gpio_to_irq().
+ * It returns the number of the IRQ signaled by this (input) GPIO,
+ * or a negative errno.
+ */
+int __gpio_to_irq(unsigned gpio)
+{
+	struct gpio_chip	*chip;
+
+	chip = gpio_to_chip(gpio);
+	return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
+}
+EXPORT_SYMBOL_GPL(__gpio_to_irq);
+
 
 
 /* There's no value in making it easy to inline GPIO calls that may sleep.
@@ -1020,7 +1358,7 @@ int gpio_get_value_cansleep(unsigned gpio)
 
 	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);
 
@@ -1049,7 +1387,7 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 			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
@@ -1128,7 +1466,7 @@ static int gpiolib_show(struct seq_file *s, void *unused)
 		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)
@@ -1149,7 +1487,7 @@ static int gpiolib_open(struct inode *inode, struct file *file)
 	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,