uio: fix irq init with dt support & irq not defined

This change also does a bit of a unification for the IRQ init code.

But the actual problem is that UIO_IRQ_NONE == 0, so for the DT case where
UIO_IRQ_NONE gets assigned to `uioinfo->irq`, a 2nd initialization will get
triggered (for the IRQ) and this one will exit via `goto bad1`.

As far as things seem to go, the only case where UIO_IRQ_NONE seems valid,
is when using a device-tree. The driver has some legacy support for old
platform_data structures. It looks like, for platform_data a non-existent
IRQ is an invalid case (or was considered an invalid case).
Which is why -ENXIO is treated only when a DT is used.

Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Acked-by: Damian Hobson-Garcia <dhobsong@igel.co.jp>
Link: https://lore.kernel.org/r/20191105073212.16719-1-alexandru.ardelean@analog.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c
index ebcf1434e296df43c753286c496df8150921d6ff..81c88f7bbbcbb63e0765035f759913aef099745f 100644 (file)
--- a/drivers/uio/uio_dmem_genirq.c
+++ b/drivers/uio/uio_dmem_genirq.c
@@ -151,8 +151,6 @@ static int uio_dmem_genirq_probe(struct platform_device *pdev)
        int i;
 
        if (pdev->dev.of_node) {
-               int irq;
-
                /* alloc uioinfo for one device */
                uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL);
                if (!uioinfo) {
@@ -163,13 +161,6 @@ static int uio_dmem_genirq_probe(struct platform_device *pdev)
                uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
                                               pdev->dev.of_node);
                uioinfo->version = "devicetree";
-
-               /* Multiple IRQs are not supported */
-               irq = platform_get_irq(pdev, 0);
-               if (irq == -ENXIO)
-                       uioinfo->irq = UIO_IRQ_NONE;
-               else
-                       uioinfo->irq = irq;
        }
 
        if (!uioinfo || !uioinfo->name || !uioinfo->version) {
@@ -199,8 +190,11 @@ static int uio_dmem_genirq_probe(struct platform_device *pdev)
        mutex_init(&priv->alloc_lock);
 
        if (!uioinfo->irq) {
+               /* Multiple IRQs are not supported */
                ret = platform_get_irq(pdev, 0);
-               if (ret < 0)
+               if (ret == -ENXIO && pdev->dev.of_node)
+                       ret = UIO_IRQ_NONE;
+               else if (ret < 0)
                        goto bad1;
                uioinfo->irq = ret;
        }