From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753054AbaHUSRt (ORCPT ); Thu, 21 Aug 2014 14:17:49 -0400 Received: from sauhun.de ([89.238.76.85]:58596 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751905AbaHUSRs (ORCPT ); Thu, 21 Aug 2014 14:17:48 -0400 Date: Thu, 21 Aug 2014 13:17:38 -0500 From: Wolfram Sang To: Sergei Shtylyov Cc: Addy Ke , max.schwarz@online.de, heiko@sntech.de, olof@lixom.net, dianders@chromium.org, huangtao@rock-chips.com, hl@rock-chips.com, yzq@rock-chips.com, zyw@rock-chips.com, linux-kernel@vger.kernel.org, kever.yang@rock-chips.com, linux-rockchip@lists.infradead.org, xjq@rock-chips.com, linux-i2c@vger.kernel.org, caesar.wang@rock-chips.com, cf@rock-chips.com, hj@rock-chips.com, zhengsq@rock-chips.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] i2c: rk3x: fix bug that cause transfer fails in master receive mode Message-ID: <20140821181738.GA1443@katana> References: <1408643457-7126-1-git-send-email-addy.ke@rock-chips.com> <53F634AF.1010303@cogentembedded.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="opJtzjQTFsWo+cga" Content-Disposition: inline In-Reply-To: <53F634AF.1010303@cogentembedded.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --opJtzjQTFsWo+cga Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Aug 21, 2014 at 10:04:31PM +0400, Sergei Shtylyov wrote: > Hello. >=20 > On 08/21/2014 09:50 PM, Addy Ke wrote: >=20 > >In rk3x SOC, the I2C controller can receive/transmit up to 32 bytes data > >in one transaction, so the size of data to be write/read to/from > >TXDATAx/RXDATAx must be less than or equal 32 bytes at a time. >=20 > >Test on pinky board, elan receive 158 bytes data. >=20 > >Signed-off-by: Addy Ke > >--- > > drivers/i2c/busses/i2c-rk3x.c | 3 +++ > > 1 file changed, 3 insertions(+) >=20 > >diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x= =2Ec > >index 69e1185..dc0aa64 100644 > >--- a/drivers/i2c/busses/i2c-rk3x.c > >+++ b/drivers/i2c/busses/i2c-rk3x.c > >@@ -323,6 +323,9 @@ static void rk3x_i2c_handle_read(struct rk3x_i2c *i2= c, unsigned int ipd) > > /* ack interrupt */ > > i2c_writel(i2c, REG_INT_MBRF, REG_IPD); > > > >+ /* Can only handle a maximum of 32 bytes at a time */ > >+ len =3D (len > 32) ? 32 : len; >=20 > Why not min(len, 32)? Or even: >=20 > if (len > 32) > len =3D 32; No silent trimming, please. The message should be rejected when the transfe= r is set up. We could assign -EOVERFLOW to that type of failures, so users will know. Sadly, I have seen other controllers having such limits :( --opJtzjQTFsWo+cga Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJT9jfCAAoJEBQN5MwUoCm2KDAP/REu6M3f6+x1V5F0pQNMXhzD 63qBo54wVv7adKVr6QwwrYMP8BBGbtjVV3jm5J+GfRrbsex8of2iYITivL67rFw/ tdZimlsP9cLgofmsd547TS54ohkKP2u5iTkxRTwn70L0a4YP3UrCZbhfjCT6QFwS pmUAoil47knaMLSKAs7mxNHzo78f9lWp3Y8HhvN8x0XReuiX0Vo/l93TW3bDgUv4 mCeP8hTKZY07Qm7sIjUquv9XGs6/68EEXnRvPqboTroArQSp/A0mQwlzlgRgO5JU GnoHaDAi88JdO4cVUQsCAasNKIj8uwbUXfwcuvZCXkyWYrVNUCySMfcyy56xuFkW AL82PyazdAjweq2PWz+K1wfs0tnQMvfQUgeR0ZEJbr2U26x5aBWzrp/vkT4KMm5E TxJwVBwvEoCkSQTDKKUoueNoMedL2zfJ30sXmedAGx75cIGZSOaaomJcpXWJfccF Sfn9jjUJu9oHx5PVqKrVxfWhxsw1ZET597tRVMhmruUjOAdlCRTTWEl6ypn2pCxx nvnc/coOhRzxchsub2EDHmWDaaBIAqA/8/Lwl7dng4OWQGYDtd9Be6haYbTlGn+v iF4kgE4UyhBYNBe/ra7EdX85RirwNv6r0F3TUtu0dOzctKrAD3+LrKvF+dMqvbcg es4ZOO2p2w/7PSIhwdCK =atpD -----END PGP SIGNATURE----- --opJtzjQTFsWo+cga--