[PATCH v3 1/3] drivers: fwnode: fix fwnode_irq_get_byname()

[Matti Vaittinen]

The fwnode_irq_get_byname() does return 0 upon device-tree IRQ mapping
failure. This is contradicting the 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 according to
the common convention and abd always return a negative errno upon failure.

Fixes: ca0acb511c21 ("device property: Add fwnode_irq_get_byname")
Suggested-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Reviewed-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
---
 drivers/base/property.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index f6117ec9805c..a3b95d2d781f 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -1011,7 +1011,7 @@ EXPORT_SYMBOL(fwnode_irq_get);
  */
 int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name)
 {
-	int index;
+	int index, ret;
 
 	if (!name)
 		return -EINVAL;
@@ -1020,7 +1020,12 @@ int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name)
 	if (index < 0)
 		return index;
 
-	return fwnode_irq_get(fwnode, index);
+	ret = fwnode_irq_get(fwnode, index);
+	/* We treat mapping errors as invalid case */
+	if (ret == 0)
+		return -EINVAL;
+
+	return ret;
 }
 EXPORT_SYMBOL(fwnode_irq_get_byname);
 
-- 
2.40.1


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]

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