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From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: linux-i2c@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Phil Reid <preid@electromag.com.au>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Jarkko Nikula <jarkko.nikula@linux.intel.com>,
	Claudio Foellmi <claudio.foellmi@ergon.ch>,
	Andrzej Hajda <a.hajda@samsung.com>
Subject: [PATCH 5/6] i2c: send STOP after successful bus recovery
Date: Mon,  4 Dec 2017 13:36:39 +0100	[thread overview]
Message-ID: <20171204123640.3382-6-wsa+renesas@sang-engineering.com> (raw)
In-Reply-To: <20171204123640.3382-1-wsa+renesas@sang-engineering.com>

If we managed to get a client release SDA again, send a STOP afterwards
to make sure we have a consistent state on the bus again.

Cc: Phil Reid <preid@electromag.com.au>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: Claudio Foellmi <claudio.foellmi@ergon.ch>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/i2c-core-base.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index dae7f4a783dbe4..29d6606d653229 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -200,6 +200,18 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 	if (bri->get_sda && !bri->get_sda(adap))
 		ret = -EBUSY;
 
+	/* If all went well, send STOP for a sane bus state. */
+	if (ret == 0 && bri->set_sda) {
+		bri->set_scl(adap, 0);
+		ndelay(RECOVERY_NDELAY / 2);
+		bri->set_sda(adap, 0);
+		ndelay(RECOVERY_NDELAY / 2);
+		bri->set_scl(adap, 1);
+		ndelay(RECOVERY_NDELAY / 2);
+		bri->set_sda(adap, 1);
+		ndelay(RECOVERY_NDELAY / 2);
+	}
+
 	if (bri->unprepare_recovery)
 		bri->unprepare_recovery(adap);
 
-- 
2.11.0

  parent reply	other threads:[~2017-12-04 12:36 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20171204123700epcas2p4273f3313a4c52e7685bbf04d776cbcef@epcas2p4.samsung.com>
2017-12-04 12:36 ` [PATCH 0/6] i2c: send STOP after recovery; use it for i2c-rcar Wolfram Sang
2017-12-04 12:36   ` [PATCH 1/6] i2c: make kerneldoc about bus recovery more precise Wolfram Sang
2017-12-04 12:36   ` [PATCH 2/6] i2c: add identifier in declarations for i2c_bus_recovery Wolfram Sang
2017-12-13 15:23     ` Andy Shevchenko
2018-01-09 11:17       ` Wolfram Sang
2017-12-04 12:36   ` [PATCH 3/6] i2c: add 'set_sda' to bus_recovery_info Wolfram Sang
2017-12-05  1:12     ` Phil Reid
2017-12-05  8:39     ` Linus Walleij
2017-12-05  9:57       ` Phil Reid
2017-12-05 10:32         ` Wolfram Sang
2017-12-05 10:34         ` Linus Walleij
2017-12-05 13:38       ` Wolfram Sang
2017-12-05 15:31         ` Linus Walleij
2017-12-05 16:43           ` Wolfram Sang
2017-12-07 11:25             ` Wolfram Sang
2017-12-10  0:24               ` Linus Walleij
2017-12-13 15:30           ` Andy Shevchenko
2018-01-09 11:23       ` Wolfram Sang
2017-12-13 15:27     ` Andy Shevchenko
2017-12-04 12:36   ` [PATCH 4/6] i2c: ensure SDA is released in recovery if SDA is controllable Wolfram Sang
2017-12-04 12:36   ` Wolfram Sang [this message]
2017-12-04 12:36   ` [PATCH 6/6] i2c: rcar: implement bus recovery Wolfram Sang
2017-12-05  1:13   ` [PATCH 0/6] i2c: send STOP after recovery; use it for i2c-rcar Phil Reid
2017-12-05  9:21   ` Andrzej Hajda
2018-01-09 11:15     ` Wolfram Sang

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