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

andy.shevchenko
2023-05-21T17:35:24Z

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 <andy.shevchenko@gmail.com>

> Fixes: ca0acb511c21 ("device property: Add fwnode_irq_get_byname")
> Suggested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
>
> ---
> 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