can: mcp251x: Use DT-supplied interrupt flags

The MCP2515 datasheet clearly describes a level-triggered interrupt pin.
Therefore the receiving interrupt controller must also be configured for
level-triggered operation otherwise there is a danger of a missed
interrupt condition blocking all subsequent interrupts. The ONESHOT
flag ensures that the interrupt is masked until the threaded interrupt
handler exits.

Rather than change the flags globally (they must have worked for at
least one user), keep the old behavior for for non DT devices. DT based
devices specify the flags in their corresonding DT node.

See: https://github.com/raspberrypi/linux/issues/2175
     https://github.com/raspberrypi/linux/issues/2263

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Tested-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index 407c02f2eb8e1bd997e2082709d679a11754f8e1..fde7509f40c780a378f41139d08a7a00e9c8816b 100644 (file)
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -913,7 +913,7 @@ static int mcp251x_open(struct net_device *net)
 {
        struct mcp251x_priv *priv = netdev_priv(net);
        struct spi_device *spi = priv->spi;
-       unsigned long flags = IRQF_ONESHOT | IRQF_TRIGGER_FALLING;
+       unsigned long flags = 0;
        int ret;
 
        ret = open_candev(net);
@@ -929,6 +929,9 @@ static int mcp251x_open(struct net_device *net)
        priv->tx_skb = NULL;
        priv->tx_len = 0;
 
+       if (!spi->dev.of_node)
+               flags = IRQF_TRIGGER_FALLING;
+
        ret = request_threaded_irq(spi->irq, NULL, mcp251x_can_ist,
                                   flags | IRQF_ONESHOT, dev_name(&spi->dev),
                                   priv);