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From: Esben Haabendal <eha-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org>
To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linuxppc-dev-mnsaURCQ41sdnm+yROfE0A@public.gmane.org
Subject: [PATCH] i2c-mpc: generate START condition after STOP caused by read i2c_msg
Date: Thu, 14 May 2009 10:10:03 +0200	[thread overview]
Message-ID: <4A0BD1DB.4090305@doredevelopment.dk> (raw)

This fixes MAL (arbitration lost) bug caused by illegal use of
RSTA (repeated START) after STOP condition generated after last byte
of reads.

Signed-off-by: Esben Haabendal <eha-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org>
---
  drivers/i2c/busses/i2c-mpc.c |    9 +++++++--
  1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index 4af5c09..9fe05d9 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -456,17 +456,22 @@ static int mpc_xfer(struct i2c_adapter *adap, 
struct i2c_msg *msgs, int num)
  	}

  	for (i = 0; ret >= 0 && i < num; i++) {
+		int restart = i;
  		pmsg = &msgs[i];
  		dev_dbg(i2c->dev,
  			"Doing %s %d bytes to 0x%02x - %d of %d messages\n",
  			pmsg->flags & I2C_M_RD ? "read" : "write",
  			pmsg->len, pmsg->addr, i + 1, num);
+		if (i > 0 && ((pmsg-1)->flags & I2C_M_RD))
+			restart = 0;
  		if (pmsg->flags & I2C_M_RD)
  			ret =
-			    mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
+			    mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len,
+				     restart);
  		else
  			ret =
-			    mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
+			    mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len,
+				      restart);
  	}
  	mpc_i2c_stop(i2c);
  	return (ret < 0) ? ret : num;
-- 
1.6.0.4

             reply	other threads:[~2009-05-14  8:10 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-14  8:10 Esben Haabendal [this message]
     [not found] ` <4A0BD1DB.4090305-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org>
2009-05-14  8:34   ` [PATCH] i2c-mpc: generate START condition after STOP caused by read i2c_msg Wolfram Sang
     [not found]     ` <20090514083453.GB3043-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2009-05-14  8:48       ` Esben Haabendal
2009-05-14  9:58         ` Joakim Tjernlund
     [not found]           ` <d2b9ea600905140317u7a4b9a70s574568d79a1ce7cc@mail.gmail.com>
     [not found]             ` <OF3CD158BA.04CCFBB5-ONC12575B6.005911D5-C12575B6.005CAFC2@transmode.se>
     [not found]               ` <OF3CD158BA.04CCFBB5-ONC12575B6.005911D5-C12575B6.005CAFC2-SNLAxHN9vbcOP4wsBPIw7w@public.gmane.org>
2009-05-15 10:18                 ` Esben Haabendal
     [not found]                   ` <d2b9ea600905150318s69b86b5ct3816b274bf343a79-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-05-15 11:05                     ` Joakim Tjernlund
     [not found]                       ` <OFCADC684E.A2599121-ONC12575B7.003B8AB5-C12575B7.003CF795-SNLAxHN9vbcOP4wsBPIw7w@public.gmane.org>
2009-05-15 12:52                         ` Esben Haabendal
     [not found]                           ` <d2b9ea600905150552u6951a92es5dd119dcc37e641d-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-05-15 14:16                             ` Joakim Tjernlund
2009-05-18 11:04                             ` Wolfram Sang

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