From: Sanman Pradhan Date: Sat, 21 Mar 2026 18:12:05 +0000 (+0000) Subject: hwmon: (pmbus/max31785) check for partial i2c_transfer in read_long_data X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=80306ba88ba6891f8cd16d4042beec69e9044de7;p=thirdparty%2Flinux.git hwmon: (pmbus/max31785) check for partial i2c_transfer in read_long_data i2c_transfer() returns the number of messages successfully transferred, not only a negative errno on failure. When called with two messages (write command byte followed by a read of the 4-byte response), a return value of 1 means the command write succeeded but the read did not complete. In that case, rspbuf remains uninitialized and must not be interpreted as valid data. Treat any return value other than ARRAY_SIZE(msg) as an error, and return -EIO for partial completion. Also return 0 on success instead of the message count, since the caller only needs to distinguish success from failure. Signed-off-by: Sanman Pradhan Link: https://lore.kernel.org/r/20260321181052.27129-4-sanman.pradhan@hpe.com Signed-off-by: Guenter Roeck --- diff --git a/drivers/hwmon/pmbus/max31785.c b/drivers/hwmon/pmbus/max31785.c index 260aa8fb50f13..3caa76bcbeb5e 100644 --- a/drivers/hwmon/pmbus/max31785.c +++ b/drivers/hwmon/pmbus/max31785.c @@ -141,13 +141,13 @@ static int max31785_read_long_data(struct i2c_client *client, int page, */ pmbus_update_ts(client, 0); - if (rc < 0) - return rc; + if (rc != ARRAY_SIZE(msg)) + return rc < 0 ? rc : -EIO; *data = (rspbuf[0] << (0 * 8)) | (rspbuf[1] << (1 * 8)) | (rspbuf[2] << (2 * 8)) | (rspbuf[3] << (3 * 8)); - return rc; + return 0; } static int max31785_get_pwm(struct i2c_client *client, int page)