linux-kernel - [PATCH v2 2/2] i2c: mark device nodes only in case of successful instantiation

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Date:   Mon, 17 Oct 2016 15:59:57 +0200
From:   Ralf Ramsauer <ralf@...ses-pyramidenbau.de>
To:     Mark Brown <broonie@...nel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Wolfram Sang <wsa@...-dreams.de>,
        Linux SPI <linux-spi@...r.kernel.org>,
        Linux I2C <linux-i2c@...r.kernel.org>
Cc:     Ralf Ramsauer <ralf@...ses-pyramidenbau.de>,
        "linux-kernel @ vger . kernel . org" <linux-kernel@...r.kernel.org>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>
Subject: [PATCH v2 2/2] i2c: mark device nodes only in case of successful instantiation

Instantiated I2C device nodes are marked with OF_POPULATE. This was
introduced in 4f001fd. On unloading, loaded device nodes will of course
be unmarked. The problem are nodes that fail during initialisation: If a
node fails, it won't be unloaded and hence not be unmarked.

If a I2C driver module is unloaded and reloaded, it will skip nodes that
failed before.

Skip device nodes that are already populated and mark them only in case
of success.

Note that the same issue exists for SPI.

Fixes: 4f001fd ("i2c: Mark instantiated device nodes with OF_POPULATE")
Signed-off-by: Ralf Ramsauer <ralf@...ses-pyramidenbau.de>
---
 drivers/i2c/i2c-core.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 5ab6721..1704fc8 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1681,6 +1681,7 @@ static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
 static void of_i2c_register_devices(struct i2c_adapter *adap)
 {
 	struct device_node *bus, *node;
+	struct i2c_client *client;
 
 	/* Only register child devices if the adapter has a node pointer set */
 	if (!adap->dev.of_node)
@@ -1695,7 +1696,14 @@ static void of_i2c_register_devices(struct i2c_adapter *adap)
 	for_each_available_child_of_node(bus, node) {
 		if (of_node_test_and_set_flag(node, OF_POPULATED))
 			continue;
-		of_i2c_register_device(adap, node);
+
+		client = of_i2c_register_device(adap, node);
+		if (IS_ERR(client)) {
+			dev_warn(&adap->dev,
+				 "Failed to create I2C device for %s\n",
+				 node->full_name);
+			of_node_clear_flag(node, OF_POPULATED);
+		}
 	}
 
 	of_node_put(bus);
@@ -2299,6 +2307,7 @@ static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
 		if (IS_ERR(client)) {
 			dev_err(&adap->dev, "failed to create client for '%s'\n",
 				 rd->dn->full_name);
+			of_node_clear_flag(rd->dn, OF_POPULATED);
 			return notifier_from_errno(PTR_ERR(client));
 		}
 		break;
-- 
2.10.1