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From: Valentin Longchamp <valentin.longchamp-p8DiymsW2f8@public.gmane.org>
To: s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
	w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
	augulis.darius-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Valentin Longchamp
	<valentin.longchamp-p8DiymsW2f8@public.gmane.org>
Subject: [PATCH] mxc i2c: let time to generate stop bit
Date: Thu, 21 Jan 2010 12:27:43 +0100	[thread overview]
Message-ID: <1264073263-16374-1-git-send-email-valentin.longchamp@epfl.ch> (raw)

After generating the stop bit by changing MSTA from 1 to 0,
the i2c_imx->stopped was immediatly set to 1. The second test
on i2c_imx->stopped then is correct and the controller never
waits if the bus is busy. This patch corrects this.

On mx31moboard, stop bit was not generated on single write transfers.
This was kept unnoticed other transfers are made afterwards that
help the write recipient to resynchronize.

Thanks to Philippe and Michael for the debugging.

Signed-off-by: Valentin Longchamp <valentin.longchamp-p8DiymsW2f8@public.gmane.org>
---
 drivers/i2c/busses/i2c-imx.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index e3654d6..602b30e 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -226,7 +226,6 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
 		temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 		temp &= ~(I2CR_MSTA | I2CR_MTX);
 		writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
-		i2c_imx->stopped = 1;
 	}
 	if (cpu_is_mx1()) {
 		/*
@@ -236,8 +235,10 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
 		udelay(i2c_imx->disable_delay);
 	}
 
-	if (!i2c_imx->stopped)
+	if (!i2c_imx->stopped) {
 		i2c_imx_bus_busy(i2c_imx, 0);
+		i2c_imx->stopped = 1;
+	}
 
 	/* Disable I2C controller */
 	writeb(0, i2c_imx->base + IMX_I2C_I2CR);
-- 
1.6.3.3

             reply	other threads:[~2010-01-21 11:27 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-21 11:27 Valentin Longchamp [this message]
     [not found] ` <1264073263-16374-1-git-send-email-valentin.longchamp-p8DiymsW2f8@public.gmane.org>
2010-01-21 11:42   ` [PATCH] mxc i2c: let time to generate stop bit Wolfram Sang
     [not found]     ` <20100121114216.GA3738-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2010-01-21 17:55       ` Valentin Longchamp
     [not found]         ` <1264096532-23580-1-git-send-email-valentin.longchamp-p8DiymsW2f8@public.gmane.org>
2010-01-21 18:09           ` Wolfram Sang

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