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From: Andrzej Hajda <a.hajda@samsung.com>
To: Wolfram Sang <wsa@the-dreams.de>, Andi Shyti <andi.shyti@samsung.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	"open list:I2C SUBSYSTEM" <linux-i2c@vger.kernel.org>,
	"moderated list:ARM/SAMSUNG EXYNOS ARM ARCHITECTURES"
	<linux-samsung-soc@vger.kernel.org>
Subject: [PATCH 3/3] i2c: exynos5: do not check TRANS_STATUS in case of Exynos7 variant
Date: Thu, 30 Nov 2017 15:30:07 +0100	[thread overview]
Message-ID: <20171130143007.30258-4-a.hajda@samsung.com> (raw)
In-Reply-To: <20171130143007.30258-1-a.hajda@samsung.com>

HSI2C_MASTER_ST_LOSE state is not documented properly, extensive tests
show that hardware is usually able to recover from this state without
interrupting the transfer. On the other side enforcing transfer repetition
in such case does not help in many situations, especially on busy systems
and causes -EAGAIN and -ETIMEOUT errors. Moreover documentation says that
such state can be caused by slave clock stretching, and should not be treated
as an error.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
---
 drivers/i2c/busses/i2c-exynos5.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
index 4ca43980e2ed..d579b45b3092 100644
--- a/drivers/i2c/busses/i2c-exynos5.c
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -445,12 +445,6 @@ static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
 			i2c->state = -ETIMEDOUT;
 			goto stop;
 		}
-
-		trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS);
-		if ((trans_status & HSI2C_MASTER_ST_MASK) == HSI2C_MASTER_ST_LOSE) {
-			i2c->state = -EAGAIN;
-			goto stop;
-		}
 	} else if (int_status & HSI2C_INT_I2C) {
 		trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS);
 		if (trans_status & HSI2C_NO_DEV_ACK) {
-- 
2.15.0

  parent reply	other threads:[~2017-11-30 14:30 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20171130143017eucas1p172b94622814eff172a27176c82f6e6fe@eucas1p1.samsung.com>
2017-11-30 14:30 ` [PATCH 0/3] i2c: exynos5: bus recovery implementation Andrzej Hajda
     [not found]   ` <CGME20171130143017eucas1p2f68094c72e4559e1a16cf334c3200950@eucas1p2.samsung.com>
2017-11-30 14:30     ` [PATCH 1/3] i2c: exynos5: change internal transmission timeout to 100ms Andrzej Hajda
2018-01-15 20:54       ` [1/3] " Wolfram Sang
     [not found]   ` <CGME20171130143018eucas1p13bd2ce9263f9ac016ab3b779920b512e@eucas1p1.samsung.com>
2017-11-30 14:30     ` [PATCH 2/3] i2c: exynos5: implement bus recovery functionality Andrzej Hajda
2018-01-15 20:52       ` [2/3] " Wolfram Sang
2018-01-16  8:35         ` Andrzej Hajda
2018-01-17 23:30           ` Wolfram Sang
     [not found]   ` <CGME20171130143018eucas1p1eba2c4f3361e0752cc53a25d217ce616@eucas1p1.samsung.com>
2017-11-30 14:30     ` Andrzej Hajda [this message]
2018-01-15 20:53       ` [3/3] i2c: exynos5: do not check TRANS_STATUS in case of Exynos7 variant Wolfram Sang
2018-01-16  9:40         ` Andrzej Hajda
2018-01-17 23:23           ` Wolfram Sang
2018-01-26  7:17             ` Andrzej Hajda
2018-01-26  9:30               ` Wolfram Sang
2017-12-07  7:36   ` [PATCH 0/3] i2c: exynos5: bus recovery implementation Andi Shyti

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