From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E02ACC433FE for ; Sun, 17 Oct 2021 10:41:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7C6361245 for ; Sun, 17 Oct 2021 10:41:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245352AbhJQKnZ (ORCPT ); Sun, 17 Oct 2021 06:43:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:54052 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245345AbhJQKnV (ORCPT ); Sun, 17 Oct 2021 06:43:21 -0400 Received: from jic23-huawei (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 50CD460D42; Sun, 17 Oct 2021 10:41:10 +0000 (UTC) Date: Sun, 17 Oct 2021 11:45:24 +0100 From: Jonathan Cameron To: Pekka Korpinen Cc: Lars-Peter Clausen , Michael Hennerich , Jean-Francois Dagenais , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 RESEND] iio: dac: ad5446: Fix ad5622_write() return value Message-ID: <20211017114524.3c1da153@jic23-huawei> In-Reply-To: <20211014173738.2446-1-pekka.korpinen@iki.fi> References: <20211014173738.2446-1-pekka.korpinen@iki.fi> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 14 Oct 2021 20:37:38 +0300 Pekka Korpinen wrote: > On success i2c_master_send() returns the number of bytes written. The > call from iio_write_channel_info(), however, expects the return value to > be zero on success. > > This bug causes incorrect consumption of the sysfs buffer in > iio_write_channel_info(). When writing more than two characters to > out_voltage0_raw, the ad5446 write handler is called multiple times > causing unexpected behavior. > > Fixes: 3ec36a2cf0d5 ("iio:ad5446: Add support for I2C based DACs") > Signed-off-by: Pekka Korpinen Hi Pekka, No need to resend a patch so soon. Feel free to just sent a 'bump' type message in reply to the original posting. Anyhow, I've picked that up today anyway (and only noticed this whilst marking it applied in patchwork). Thanks, Jonathan > --- > v1->v2: Check against expected result, otherwise -EIO. Add Fixes tag. > > A similar bug was fixed for ad5064.c in 2015 - commit 03fe472ef33b > ("iio:ad5064: Make sure ad5064_i2c_write() returns 0 on success"). > > drivers/iio/dac/ad5446.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/dac/ad5446.c b/drivers/iio/dac/ad5446.c > index 488ec69967d6..e50718422411 100644 > --- a/drivers/iio/dac/ad5446.c > +++ b/drivers/iio/dac/ad5446.c > @@ -531,8 +531,15 @@ static int ad5622_write(struct ad5446_state *st, unsigned val) > { > struct i2c_client *client = to_i2c_client(st->dev); > __be16 data = cpu_to_be16(val); > + int ret; > + > + ret = i2c_master_send(client, (char *)&data, sizeof(data)); > + if (ret < 0) > + return ret; > + if (ret != sizeof(data)) > + return -EIO; > > - return i2c_master_send(client, (char *)&data, sizeof(data)); > + return 0; > } > > /*