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gpio: sysfs: fix redundant lock-as-irq handling 

Drivers should call gpiochip_lock_as_irq (which prevents the pin
direction from being changed) in their irq_request_resources callbacks
but some drivers currently fail to do so.

Instead a second, explicit and often redundant call to lock-as-irq is
made by the sysfs-interface implementation after an irq has been
requested.

Move the explicit call before the irq-request to match the unlock done
after the irq is later released. Note that this also fixes an irq leak,
should the explicit call ever have failed.

Also add a comment about removing the redundant call once the broken
drivers have been fixed.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Johan Hovold 2015-05-04 17:10:28 +02:00 committed by Linus Walleij
parent fab28b89a1
commit 52176d0d3b
1 changed files with 15 additions and 7 deletions
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22
drivers/gpio/gpiolib-sysfs.c
View File

@ -195,20 +195,28 @@ static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
}
}
ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
"gpiolib", value_sd);
/*
* FIXME: This should be done in the irq_request_resources callback
* when the irq is requested, but a few drivers currently fail
* to do so.
*
* Remove this redundant call (along with the corresponding
* unlock) when those drivers have been fixed.
*/
ret = gpiochip_lock_as_irq(desc->chip, gpio_chip_hwgpio(desc));
if (ret < 0)
goto free_id;
ret = gpiochip_lock_as_irq(desc->chip, gpio_chip_hwgpio(desc));
if (ret < 0) {
gpiod_warn(desc, "failed to flag the GPIO for IRQ\n");
goto free_id;
}
ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
"gpiolib", value_sd);
if (ret < 0)
goto err_unlock;
desc->flags |= gpio_flags;
return 0;
err_unlock:
gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc));
free_id:
idr_remove(&dirent_idr, id);
desc->flags &= GPIO_FLAGS_MASK;