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Mon, 27 Apr 2026 11:47:57 -0700 (PDT) Received: from localhost.localdomain ([196.235.239.18]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4463fa89140sm242134f8f.27.2026.04.27.11.47.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Apr 2026 11:47:57 -0700 (PDT) From: Salah Triki To: Jonathan Cameron , David Lechner , =?UTF-8?q?Nuno=20S=C3=A1?= , Andy Shevchenko Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Salah Triki Subject: [PATCH] iio: dac: max5821: fix return value check in powerdown sync Date: Mon, 27 Apr 2026 19:47:46 +0100 Message-ID: <20260427184747.12149-1-salah.triki@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The function max5821_sync_powerdown_mode() previously returned the result of i2c_master_send() directly. This is problematic because: 1. A successful I2C transfer returns the number of bytes sent (2), but the caller might expect 0 for success. 2. If a partial transfer occurs (e.g., only 1 byte sent), it would be treated as success by the caller checking for negative values. This patch refactors the return value handling to: - Propagate negative error codes from the I2C core. - Return -EIO in case of incomplete transfers (short writes). - Return 0 on complete success. Fixes: 472988972737 ("iio: add support of the max5821") Signed-off-by: Salah Triki --- drivers/iio/dac/max5821.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/iio/dac/max5821.c b/drivers/iio/dac/max5821.c index e7e29359f8fe..bd14f578d8c5 100644 --- a/drivers/iio/dac/max5821.c +++ b/drivers/iio/dac/max5821.c @@ -90,6 +90,7 @@ static int max5821_sync_powerdown_mode(struct max5821_dat= a *data, const struct iio_chan_spec *chan) { u8 outbuf[2]; + int ret; =20 outbuf[0] =3D MAX5821_EXTENDED_COMMAND_MODE; =20 @@ -103,7 +104,15 @@ static int max5821_sync_powerdown_mode(struct max5821_= data *data, else outbuf[1] |=3D MAX5821_EXTENDED_POWER_UP; =20 - return i2c_master_send(data->client, outbuf, 2); + ret =3D i2c_master_send(data->client, outbuf, 2); + + if (ret < 0) + return ret; + + if (ret !=3D 2) + return -EIO; + + return 0; } =20 static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev, --=20 2.43.0