EDAC, altera: Check parent status for Arria10 EDAC block

In preparation for the Arria10 ECC modules, check the status of the
parent in the device tree to ensure the block is enabled. Skip if no
parent phandle is set in the device tree.

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1466603939-7526-2-git-send-email-tthayer@opensource.altera.com
Signed-off-by: Borislav Petkov <bp@suse.de>

diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
index 1c26e22c5b68d9aee7cfb1c180ef0ab47d8e20d9..453e92c786c8b1d4234e739eef2daadadfff0bcf 100644 (file)
--- a/drivers/edac/altera_edac.c
+++ b/drivers/edac/altera_edac.c
@@ -1125,6 +1125,20 @@ static void altr_edac_a10_irq_handler(struct irq_desc *desc)
        chained_irq_exit(chip, desc);
 }
 
+static int validate_parent_available(struct device_node *np)
+{
+       struct device_node *parent;
+       int ret = 0;
+
+       /* Ensure parent device is enabled if parent node exists */
+       parent = of_parse_phandle(np, "altr,ecc-parent", 0);
+       if (parent && !of_device_is_available(parent))
+               ret = -ENODEV;
+
+       of_node_put(parent);
+       return ret;
+}
+
 static int altr_edac_a10_device_add(struct altr_arria10_edac *edac,
                                    struct device_node *np)
 {
@@ -1146,6 +1160,9 @@ static int altr_edac_a10_device_add(struct altr_arria10_edac *edac,
        if (IS_ERR_OR_NULL(prv))
                return -ENODEV;
 
+       if (validate_parent_available(np))
+               return -ENODEV;
+
        if (!devres_open_group(edac->dev, altr_edac_a10_device_add, GFP_KERNEL))
                return -ENOMEM;