diff options
Diffstat (limited to 'drivers/gpio/gpiolib.c')
| -rw-r--r-- | drivers/gpio/gpiolib.c | 124 |
1 files changed, 84 insertions, 40 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 58b9838801c0..199fca15f270 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 @@ -1304,9 +1341,15 @@ 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", @@ -1842,6 +1885,7 @@ 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, |