net: ks8851: Delay requesting IRQ until opened [Linux 5.1]

net: ks8851: Delay requesting IRQ until opened [Linux 5.1]

This Linux kernel change "net: ks8851: Delay requesting IRQ until opened" is included in the Linux 5.1 release. This change is authored by Lukas Wunner <lukas [at] wunner.de> on Wed Mar 20 15:02:00 2019 +0100. The commit for this change in Linux stable tree is d268f31 (patch).

net: ks8851: Delay requesting IRQ until opened

The ks8851 driver currently requests the IRQ before registering the
net_device.  Because the net_device name is used as IRQ name and is
still "eth%d" when the IRQ is requested, it's impossibe to tell IRQs
apart if multiple ks8851 chips are present.  Most other drivers delay
requesting the IRQ until the net_device is opened.  Do the same.

The driver doesn't enable interrupts on the chip before opening the
net_device and disables them when closing it, so there doesn't seem to
be a need to request the IRQ already on probe.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There are 24 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/net/ethernet/micrel/ks8851.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/micrel/ks8851.c b/drivers/net/ethernet/micrel/ks8851.c
index 1633fa5..c9faec4 100644
--- a/drivers/net/ethernet/micrel/ks8851.c
+++ b/drivers/net/ethernet/micrel/ks8851.c
@@ -785,6 +785,15 @@ static void ks8851_tx_work(struct work_struct *work)
 static int ks8851_net_open(struct net_device *dev)
 {
    struct ks8851_net *ks = netdev_priv(dev);
+   int ret;
+
+   ret = request_threaded_irq(dev->irq, NULL, ks8851_irq,
+                  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+                  dev->name, ks);
+   if (ret < 0) {
+       netdev_err(dev, "failed to get irq\n");
+       return ret;
+   }

    /* lock the card, even if we may not actually be doing anything
     * else at the moment */
@@ -899,6 +908,8 @@ static int ks8851_net_stop(struct net_device *dev)
        dev_kfree_skb(txb);
    }

+   free_irq(dev->irq, ks);
+
    return 0;
 }

@@ -1529,14 +1540,6 @@ static int ks8851_probe(struct spi_device *spi)
    ks8851_read_selftest(ks);
    ks8851_init_mac(ks);

-   ret = request_threaded_irq(spi->irq, NULL, ks8851_irq,
-                  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
-                  ndev->name, ks);
-   if (ret < 0) {
-       dev_err(&spi->dev, "failed to get irq\n");
-       goto err_irq;
-   }
-
    ret = register_netdev(ndev);
    if (ret) {
        dev_err(&spi->dev, "failed to register network device\n");
@@ -1549,11 +1552,7 @@ static int ks8851_probe(struct spi_device *spi)

    return 0;

-
 err_netdev:
-   free_irq(ndev->irq, ks);
-
-err_irq:
 err_id:
    if (gpio_is_valid(gpio))
        gpio_set_value(gpio, 0);
@@ -1574,7 +1573,6 @@ static int ks8851_remove(struct spi_device *spi)
        dev_info(&spi->dev, "remove\n");

    unregister_netdev(priv->netdev);
-   free_irq(spi->irq, priv);
    if (gpio_is_valid(priv->gpio))
        gpio_set_value(priv->gpio, 0);
    regulator_disable(priv->vdd_reg);

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