From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out2-smtp.messagingengine.com ([66.111.4.26]:53699 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726024AbeGOKcw (ORCPT ); Sun, 15 Jul 2018 06:32:52 -0400 Subject: FAILED: patch "[PATCH] i2c: recovery: if possible send STOP with recovery pulses" failed to apply to 4.14-stable tree To: wsa+renesas@sang-engineering.com, peda@axentia.se, wsa@the-dreams.de Cc: From: Date: Sun, 15 Jul 2018 12:10:23 +0200 Message-ID: <1531649423110@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From abe41184abac487264a4904bfcff2d5500dccce6 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Tue, 10 Jul 2018 23:42:15 +0200 Subject: [PATCH] i2c: recovery: if possible send STOP with recovery pulses I2C clients may misunderstand recovery pulses if they can't read SDA to bail out early. In the worst case, as a write operation. To avoid that and if we can write SDA, try to send STOP to avoid the misinterpretation. Signed-off-by: Wolfram Sang Reviewed-by: Peter Rosin Signed-off-by: Wolfram Sang Cc: stable@kernel.org diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 31d16ada6e7d..301285c54603 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -198,7 +198,16 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) val = !val; bri->set_scl(adap, val); - ndelay(RECOVERY_NDELAY); + + /* + * If we can set SDA, we will always create STOP here to ensure + * the additional pulses will do no harm. This is achieved by + * letting SDA follow SCL half a cycle later. + */ + ndelay(RECOVERY_NDELAY / 2); + if (bri->set_sda) + bri->set_sda(adap, val); + ndelay(RECOVERY_NDELAY / 2); } /* check if recovery actually succeeded */