Subject: Re: [PATCH v5 1/8] drivers: fwnode: fix fwnode_irq_get[_byname]()

From: [email-masked]
Date: Sun, 21 May 2023 20:13:16 +0300

Fri, May 19, 2023 at 02:00:54PM +0300, Matti Vaittinen kirjoitti:
> The fwnode_irq_get() and the fwnode_irq_get_byname() return 0 upon
> device-tree IRQ mapping failure. This is contradicting the
> fwnode_irq_get_byname() function documentation and can potentially be a
> source of errors like:
> 
> int probe(...) {
> 	...
> 
> 	irq = fwnode_irq_get_byname();
> 	if (irq <= 0)
> 		return irq;
> 
> 	...
> }
> 
> Here we do correctly check the return value from fwnode_irq_get_byname()
> but the driver probe will now return success. (There was already one
> such user in-tree).
> 
> Change the fwnode_irq_get_byname() to work as documented and make also the
> fwnode_irq_get() follow same common convention returning a negative errno
> upon failure.

Reviewed-by: Andy Shevchenko <[email-masked]>

> Fixes: ca0acb511c21 ("device property: Add fwnode_irq_get_byname")
> Suggested-by: Sakari Ailus <[email-masked]>
> Suggested-by: Jonathan Cameron <[email-masked]>
> Signed-off-by: Matti Vaittinen <[email-masked]>
> 
> ---
> I dropped the existing reviewed-by tags because change to
> fwnode_irq_get() was added.
> 
> Revision history:
> v3 => v4:
>  - Change also the fwnode_irq_get()
> ---
>  drivers/base/property.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index f6117ec9805c..8c40abed7852 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -987,12 +987,18 @@ EXPORT_SYMBOL(fwnode_iomap);
>   * @fwnode:	Pointer to the firmware node
>   * @index:	Zero-based index of the IRQ
>   *
> - * Return: Linux IRQ number on success. Other values are determined
> - * according to acpi_irq_get() or of_irq_get() operation.
> + * Return: Linux IRQ number on success. Negative errno on failure.
>   */
>  int fwnode_irq_get(const struct fwnode_handle *fwnode, unsigned int index)
>  {
> -	return fwnode_call_int_op(fwnode, irq_get, index);
> +	int ret;
> +
> +	ret = fwnode_call_int_op(fwnode, irq_get, index);
> +	/* We treat mapping errors as invalid case */
> +	if (ret == 0)
> +		return -EINVAL;

Not sure if this is the best choice, perhaps -EEXIST or -ENOENT might be
better, but it's just a spoken up thought.

> +	return ret;
>  }
>  EXPORT_SYMBOL(fwnode_irq_get);

-- 
With Best Regards,
Andy Shevchenko