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[v4,4/4] hwmon: lm75: Handle broken device nodes gracefully

Message ID 20210206095121.20625-5-matwey@sai.msu.ru (mailing list archive)
State New
Headers show
Series hwmon: lm75: Handle broken device nodes gracefully | expand

Commit Message

Matwey V. Kornilov Feb. 6, 2021, 9:51 a.m. UTC
There is a logical flaw in lm75_probe() function introduced in

    e97a45f1b460 ("hwmon: (lm75) Add OF device ID table")

Note, that of_device_get_match_data() returns NULL when no match
is found. This is the case when OF node exists but has unknown
compatible line, while the module is still loaded via i2c


    lm75b@48 {
    	compatible = "nxp,lm75a";
    	reg = <0x48>;

In this case, the sensor is mistakenly considered as ADT75 variant.

Fixes: e97a45f1b460 ("hwmon: (lm75) Add OF device ID table")
Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
 drivers/hwmon/lm75.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
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diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index 3e4374aa2f99..cd2cda4f557a 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -567,10 +567,17 @@  static int lm75_probe(struct i2c_client *client)
 	int status, err;
 	enum lm75_type kind;
-	if (client->dev.of_node)
-		kind = (enum lm75_type)of_device_get_match_data(&client->dev);
-	else
+	if (dev->of_node) {
+		const struct of_device_id *match =
+			of_match_device(dev->driver->of_match_table, dev);
+		if (!match)
+			return -ENODEV;
+		kind = (enum lm75_type)(match->data);
+	} else {
 		kind = i2c_match_id(lm75_ids, client)->driver_data;
+	}
 	if (!i2c_check_functionality(client->adapter,