[PATCH v1 1/1] driver core: platform: Make platform_get_irq_optional() optional

From: Andy Shevchenko
Date: Wed Mar 31 2021 - 10:45:57 EST


Currently the platform_get_irq_optional() returns an error code even
if IRQ resource sumply has not been found. It prevents caller to be
error code agnostic in their error handling.

Now:
ret = platform_get_irq_optional(...);
if (ret != -ENXIO)
return ret; // respect deferred probe
if (ret > 0)
...we get an IRQ...

After proposed change:
ret = platform_get_irq_optional(...);
if (ret < 0)
return ret;
if (ret > 0)
...we get an IRQ...

Reported-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/base/platform.c | 55 +++++++++++++++++++++++++----------------
1 file changed, 34 insertions(+), 21 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 6e1f8e0b661c..d82db3eabcd4 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -168,25 +168,7 @@ devm_platform_ioremap_resource_byname(struct platform_device *pdev,
EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource_byname);
#endif /* CONFIG_HAS_IOMEM */

-/**
- * platform_get_irq_optional - get an optional IRQ for a device
- * @dev: platform device
- * @num: IRQ number index
- *
- * Gets an IRQ for a platform device. Device drivers should check the return
- * value for errors so as to not pass a negative integer value to the
- * request_irq() APIs. This is the same as platform_get_irq(), except that it
- * does not print an error message if an IRQ can not be obtained.
- *
- * For example::
- *
- * int irq = platform_get_irq_optional(pdev, 0);
- * if (irq < 0)
- * return irq;
- *
- * Return: non-zero IRQ number on success, negative error number on failure.
- */
-int platform_get_irq_optional(struct platform_device *dev, unsigned int num)
+static int platform_do_get_irq(struct platform_device *dev, unsigned int num)
{
int ret;
#ifdef CONFIG_SPARC
@@ -255,6 +237,37 @@ int platform_get_irq_optional(struct platform_device *dev, unsigned int num)
WARN(ret == 0, "0 is an invalid IRQ number\n");
return ret;
}
+
+/**
+ * platform_get_irq_optional - get an optional IRQ for a device
+ * @dev: platform device
+ * @num: IRQ number index
+ *
+ * Gets an IRQ for a platform device. Device drivers should check the return
+ * value for errors so as to not pass a negative integer value to the
+ * request_irq() APIs. This is the same as platform_get_irq(), except that it
+ * does not print an error message if an IRQ can not be obtained and returns
+ * 0 when IRQ resource has not been found.
+ *
+ * For example::
+ *
+ * int irq = platform_get_irq_optional(pdev, 0);
+ * if (irq < 0)
+ * return irq;
+ * if (irq > 0)
+ * ...we have IRQ line defined...
+ *
+ * Return: non-zero IRQ number on success, negative error number on failure.
+ */
+int platform_get_irq_optional(struct platform_device *dev, unsigned int num)
+{
+ int ret;
+
+ ret = platform_do_get_irq(dev, num);
+ if (ret == -ENXIO)
+ return 0;
+ return ret;
+}
EXPORT_SYMBOL_GPL(platform_get_irq_optional);

/**
@@ -278,7 +291,7 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
{
int ret;

- ret = platform_get_irq_optional(dev, num);
+ ret = platform_do_get_irq(dev, num);
if (ret < 0 && ret != -EPROBE_DEFER)
dev_err(&dev->dev, "IRQ index %u not found\n", num);

@@ -296,7 +309,7 @@ int platform_irq_count(struct platform_device *dev)
{
int ret, nr = 0;

- while ((ret = platform_get_irq_optional(dev, nr)) >= 0)
+ while ((ret = platform_do_get_irq(dev, nr)) >= 0)
nr++;

if (ret == -EPROBE_DEFER)
--
2.30.2