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Commit 159f3cd9 authored by Guenter Roeck's avatar Guenter Roeck Committed by Linus Walleij
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gpiolib: Defer gpio device setup until after gpiolib initialization 



Since commit ff2b1359 ("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: ff2b1359 ("gpio: make the gpiochip a real device")
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 476e2fc5

drivers/gpio/gpiolib.c

+67 −31
Original line number Diff line number Diff line
@@ -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 (gpiolib_initialized) {

		status = gpiochip_setup_dev(gdev);

		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");



			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;

}