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gpiolib: Defer gpio device setup until after gpiolib initialization 

Since commit ff2b135922 ("gpio: make the gpiochip a real device"),
attempts to add a gpio chip prior to gpiolib initialization cause
the system to crash. This happens because gpio_bus_type has not been
registered yet. Defer creating gpio devices until after gpiolib has
been initialized to fix the problem.

Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Fixes: ff2b135922 ("gpio: make the gpiochip a real device")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Guenter Roeck 2016-03-31 08:11:30 -07:00 committed by Linus Walleij
parent 476e2fc5cd
commit 159f3cd92f
1 changed files with 67 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

98
drivers/gpio/gpiolib.c
View File

@ -68,6 +68,7 @@ LIST_HEAD(gpio_devices);
static void gpiochip_free_hogs(struct gpio_chip *chip);
static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);
static bool gpiolib_initialized;
static inline void desc_set_label(struct gpio_desc *d, const char *label)
{
@ -445,6 +446,58 @@ static void gpiodevice_release(struct device *dev)
kfree(gdev);
}
static int gpiochip_setup_dev(struct gpio_device *gdev)
{
int status;
cdev_init(&gdev->chrdev, &gpio_fileops);
gdev->chrdev.owner = THIS_MODULE;
gdev->chrdev.kobj.parent = &gdev->dev.kobj;
gdev->dev.devt = MKDEV(MAJOR(gpio_devt), gdev->id);
status = cdev_add(&gdev->chrdev, gdev->dev.devt, 1);
if (status < 0)
chip_warn(gdev->chip, "failed to add char device %d:%d\n",
MAJOR(gpio_devt), gdev->id);
else
chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
MAJOR(gpio_devt), gdev->id);
status = device_add(&gdev->dev);
if (status)
goto err_remove_chardev;
status = gpiochip_sysfs_register(gdev);
if (status)
goto err_remove_device;
/* From this point, the .release() function cleans up gpio_device */
gdev->dev.release = gpiodevice_release;
get_device(&gdev->dev);
pr_debug("%s: registered GPIOs %d to %d on device: %s (%s)\n",
__func__, gdev->base, gdev->base + gdev->ngpio - 1,
dev_name(&gdev->dev), gdev->chip->label ? : "generic");
return 0;
err_remove_device:
device_del(&gdev->dev);
err_remove_chardev:
cdev_del(&gdev->chrdev);
return status;
}
static void gpiochip_setup_devs(void)
{
struct gpio_device *gdev;
int err;
list_for_each_entry(gdev, &gpio_devices, list) {
err = gpiochip_setup_dev(gdev);
if (err)
pr_err("%s: Failed to initialize gpio device (%d)\n",
dev_name(&gdev->dev), err);
}
}
/**
* gpiochip_add_data() - register a gpio_chip
* @chip: the chip to register, with chip->base initialized
@ -459,6 +512,9 @@ static void gpiodevice_release(struct device *dev)
* the gpio framework's arch_initcall(). Otherwise sysfs initialization
* for GPIOs will fail rudely.
*
* gpiochip_add_data() must only be called after gpiolib initialization,
* ie after core_initcall().
*
* If chip->base is negative, this requests dynamic assignment of
* a range of valid GPIOs.
*/
@ -515,7 +571,7 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
if (chip->ngpio == 0) {
chip_err(chip, "tried to insert a GPIO chip with zero lines\n");
status = -EINVAL;
goto err_free_gdev;
goto err_free_descs;
}
if (chip->label)
@ -597,39 +653,16 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
* we get a device node entry in sysfs under
* /sys/bus/gpio/devices/gpiochipN/dev that can be used for
* coldplug of device nodes and other udev business.
* We can do this only if gpiolib has been initialized.
* Otherwise, defer until later.
*/
cdev_init(&gdev->chrdev, &gpio_fileops);
gdev->chrdev.owner = THIS_MODULE;
gdev->chrdev.kobj.parent = &gdev->dev.kobj;
gdev->dev.devt = MKDEV(MAJOR(gpio_devt), gdev->id);
status = cdev_add(&gdev->chrdev, gdev->dev.devt, 1);
if (status < 0)
chip_warn(chip, "failed to add char device %d:%d\n",
MAJOR(gpio_devt), gdev->id);
else
chip_dbg(chip, "added GPIO chardev (%d:%d)\n",
MAJOR(gpio_devt), gdev->id);
status = device_add(&gdev->dev);
if (status)
goto err_remove_chardev;
status = gpiochip_sysfs_register(gdev);
if (status)
goto err_remove_device;
/* From this point, the .release() function cleans up gpio_device */
gdev->dev.release = gpiodevice_release;
get_device(&gdev->dev);
pr_debug("%s: registered GPIOs %d to %d on device: %s (%s)\n",
__func__, gdev->base, gdev->base + gdev->ngpio - 1,
dev_name(&gdev->dev), chip->label ? : "generic");
if (gpiolib_initialized) {
status = gpiochip_setup_dev(gdev);
if (status)
goto err_remove_chip;
}
return 0;
err_remove_device:
device_del(&gdev->dev);
err_remove_chardev:
cdev_del(&gdev->chrdev);
err_remove_chip:
acpi_gpiochip_remove(chip);
gpiochip_free_hogs(chip);
@ -2842,6 +2875,9 @@ static int __init gpiolib_dev_init(void)
if (ret < 0) {
pr_err("gpiolib: failed to allocate char dev region\n");
bus_unregister(&gpio_bus_type);
} else {
gpiolib_initialized = true;
gpiochip_setup_devs();
}
return ret;
}