1 files changed, 84 insertions, 40 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index c5f650095faa..b667f768c23b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -191,6 +191,32 @@ err:
         return ret;
 }
 
+/* caller ensures gpio is valid and requested, chip->get_direction may sleep  */
+static int gpio_get_direction(unsigned gpio)
+{
+        struct gpio_chip        *chip;
+        struct gpio_desc        *desc = &gpio_desc[gpio];
+        int                     status = -EINVAL;
+
+        chip = gpio_to_chip(gpio);
+        gpio -= chip->base;
+
+        if (!chip->get_direction)
+                return status;
+
+        status = chip->get_direction(chip, gpio);
+        if (status > 0) {
+                /* GPIOF_DIR_IN, or other positive */
+                status = 1;
+                clear_bit(FLAG_IS_OUT, &desc->flags);
+        }
+        if (status == 0) {
+                /* GPIOF_DIR_OUT */
+                set_bit(FLAG_IS_OUT, &desc->flags);
+        }
+        return status;
+}
+
 #ifdef CONFIG_GPIO_SYSFS
 
 /* lock protects against unexport_gpio() being called while
@@ -223,6 +249,7 @@ static ssize_t gpio_direction_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
 {
         const struct gpio_desc  *desc = dev_get_drvdata(dev);
+        unsigned                gpio = desc - gpio_desc;
         ssize_t                 status;
 
         mutex_lock(&sysfs_lock);
@@ -230,6 +257,7 @@ static ssize_t gpio_direction_show(struct device *dev,
         if (!test_bit(FLAG_EXPORT, &desc->flags))
                 status = -EIO;
         else
+                gpio_get_direction(gpio);
                 status = sprintf(buf, "%s\n",
                         test_bit(FLAG_IS_OUT, &desc->flags)
                                 ? "out" : "in");
@@ -704,8 +732,9 @@ int gpio_export(unsigned gpio, bool direction_may_change)
 {
         unsigned long           flags;
         struct gpio_desc        *desc;
-        int                     status = -EINVAL;
+        int                     status;
         const char              *ioname = NULL;
+        struct device           *dev;
 
         /* can't export until sysfs is available ... */
         if (!gpio_class.p) {
@@ -713,59 +742,66 @@ int gpio_export(unsigned gpio, bool direction_may_change)
                 return -ENOENT;
         }
 
-        if (!gpio_is_valid(gpio))
-                goto done;
+        if (!gpio_is_valid(gpio)) {
+                pr_debug("%s: gpio %d is not valid\n", __func__, gpio);
+                return -EINVAL;
+        }
 
         mutex_lock(&sysfs_lock);
 
         spin_lock_irqsave(&gpio_lock, flags);
         desc = &gpio_desc[gpio];
-        if (test_bit(FLAG_REQUESTED, &desc->flags)
-                        && !test_bit(FLAG_EXPORT, &desc->flags)) {
-                status = 0;
-                if (!desc->chip->direction_input
-                                || !desc->chip->direction_output)
-                        direction_may_change = false;
+        if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
+             test_bit(FLAG_EXPORT, &desc->flags)) {
+                spin_unlock_irqrestore(&gpio_lock, flags);
+                pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
+                                __func__, gpio,
+                                test_bit(FLAG_REQUESTED, &desc->flags),
+                                test_bit(FLAG_EXPORT, &desc->flags));
+                status = -EPERM;
+                goto fail_unlock;
         }
+
+        if (!desc->chip->direction_input || !desc->chip->direction_output)
+                direction_may_change = false;
         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, ioname ? ioname : "gpio%u", gpio);
-                if (!IS_ERR(dev)) {
-                        status = sysfs_create_group(&dev->kobj,
-                                                &gpio_attr_group);
-
-                        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_edge);
-
-                        if (status != 0)
-                                device_unregister(dev);
-                } else
-                        status = PTR_ERR(dev);
-                if (status == 0)
-                        set_bit(FLAG_EXPORT, &desc->flags);
+        dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
+                            desc, ioname ? ioname : "gpio%u", gpio);
+        if (IS_ERR(dev)) {
+                status = PTR_ERR(dev);
+                goto fail_unlock;
         }
 
-        mutex_unlock(&sysfs_lock);
-
-done:
+        status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
         if (status)
-                pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+                goto fail_unregister_device;
 
+        if (direction_may_change) {
+                status = device_create_file(dev, &dev_attr_direction);
+                if (status)
+                        goto fail_unregister_device;
+        }
+
+        if (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)
+                        goto fail_unregister_device;
+        }
+
+        set_bit(FLAG_EXPORT, &desc->flags);
+        mutex_unlock(&sysfs_lock);
+        return 0;
+
+fail_unregister_device:
+        device_unregister(dev);
+fail_unlock:
+        mutex_unlock(&sysfs_lock);
+        pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
         return status;
 }
 EXPORT_SYMBOL_GPL(gpio_export);
@@ -1075,6 +1111,7 @@ int gpiochip_add(struct gpio_chip *chip)
                          * inputs (often with pullups enabled) so power
                          * usage is minimized.  Linux code should set the
                          * gpio direction first thing; but until it does,
+                         * and in case chip->get_direction is not set,
                          * we may expose the wrong direction in sysfs.
                          */
                         gpio_desc[id].flags = !chip->direction_input
@@ -1274,9 +1311,15 @@ int gpio_request(unsigned gpio, const char *label)
                         desc_set_label(desc, NULL);
                         module_put(chip->owner);
                         clear_bit(FLAG_REQUESTED, &desc->flags);
+                        goto done;
                 }
         }
-
+        if (chip->get_direction) {
+                /* chip->get_direction may sleep */
+                spin_unlock_irqrestore(&gpio_lock, flags);
+                gpio_get_direction(gpio);
+                spin_lock_irqsave(&gpio_lock, flags);
+        }
 done:
         if (status)
                 pr_debug("gpio_request: gpio-%d (%s) status %d\n",
@@ -1812,6 +1855,7 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
                 if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
                         continue;
 
+                gpio_get_direction(gpio);
                 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
                 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
                         gpio, gdesc->label,