can: flexcan: Deferred on Regulator return EPROBE_DEFER

Return EPROBE_DEFER if Regulator returns EPROBE_DEFER

If the Flexcan driver is built into kernel and a regulator is used to
enable the CAN transceiver, the Flexcan driver may not use the regulator.

When initializing the Flexcan device with a regulator defined in the device
tree, but not initialized, the regulator subsystem returns EPROBE_DEFER, hence
the Flexcan init fails.

The solution for this is to return EPROBE_DEFER if regulator is not initialized
and wait until the regulator is initialized.

Signed-off-by: Andreas Werner <kernel@andy89.org>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index ee944ae..ad0a7e8 100644 (file)
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -1157,12 +1157,19 @@ static int flexcan_probe(struct platform_device *pdev)
        const struct flexcan_devtype_data *devtype_data;
        struct net_device *dev;
        struct flexcan_priv *priv;
+       struct regulator *reg_xceiver;
        struct resource *mem;
        struct clk *clk_ipg = NULL, *clk_per = NULL;
        void __iomem *base;
        int err, irq;
        u32 clock_freq = 0;
 
+       reg_xceiver = devm_regulator_get(&pdev->dev, "xceiver");
+       if (PTR_ERR(reg_xceiver) == -EPROBE_DEFER)
+               return -EPROBE_DEFER;
+       else if (IS_ERR(reg_xceiver))
+               reg_xceiver = NULL;
+
        if (pdev->dev.of_node)
                of_property_read_u32(pdev->dev.of_node,
                                                "clock-frequency", &clock_freq);
@@ -1223,9 +1230,7 @@ static int flexcan_probe(struct platform_device *pdev)
        priv->pdata = dev_get_platdata(&pdev->dev);
        priv->devtype_data = devtype_data;
 
-       priv->reg_xceiver = devm_regulator_get(&pdev->dev, "xceiver");
-       if (IS_ERR(priv->reg_xceiver))
-               priv->reg_xceiver = NULL;
+       priv->reg_xceiver = reg_xceiver;
 
        netif_napi_add(dev, &priv->napi, flexcan_poll, FLEXCAN_NAPI_WEIGHT);