linux-kernel - [PATCH] bfin_twi: Remove useless twi

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Date:	Wed, 12 Sep 2007 11:48:34 +0800
From:	Bryan Wu <bryan.wu@...log.com>
To:	Francis Moreau <francis.moro@...il.com>,
	Sonic Zhang <sonic.zhang@...log.com>,
	Jean Delvare <khali@...ux-fr.org>, i2c@...sensors.org,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH] bfin_twi: Remove useless twi_lock mutex


This patch removes this unneeded mutex. Indeed it was used
to serialized access to the hardware, but this is already
done by the i2c-core layer, see 'bus_lock' mutex used by
i2c_transfer().

Signed-off-by: Francis Moreau <francis.moro@...il.com>
Acked-by: Bryan Wu <bryan.wu@...log.com>
Acked-by: Sonic Zhang <sonic.zhang@...log.com>
---
 drivers/i2c/busses/i2c-bfin-twi.c |   16 ----------------
 1 files changed, 0 insertions(+), 16 deletions(-)

diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c
index 6311039..67224a4 100644
--- a/drivers/i2c/busses/i2c-bfin-twi.c
+++ b/drivers/i2c/busses/i2c-bfin-twi.c
@@ -44,7 +44,6 @@
 #define TWI_I2C_MODE_COMBINED		0x04
 
 struct bfin_twi_iface {
-	struct mutex		twi_lock;
 	int			irq;
 	spinlock_t		lock;
 	char			read_write;
@@ -228,12 +227,8 @@ static int bfin_twi_master_xfer(struct i2c_adapter *adap,
 	if (!(bfin_read_TWI_CONTROL() & TWI_ENA))
 		return -ENXIO;
 
-	mutex_lock(&iface->twi_lock);
-
 	while (bfin_read_TWI_MASTER_STAT() & BUSBUSY) {
-		mutex_unlock(&iface->twi_lock);
 		yield();
-		mutex_lock(&iface->twi_lock);
 	}
 
 	ret = 0;
@@ -310,9 +305,6 @@ static int bfin_twi_master_xfer(struct i2c_adapter *adap,
 			break;
 	}
 
-	/* Release mutex */
-	mutex_unlock(&iface->twi_lock);
-
 	return ret;
 }
 
@@ -330,12 +322,8 @@ int bfin_twi_smbus_xfer(struct i2c_adapter *adap, u16 addr,
 	if (!(bfin_read_TWI_CONTROL() & TWI_ENA))
 		return -ENXIO;
 
-	mutex_lock(&iface->twi_lock);
-
 	while (bfin_read_TWI_MASTER_STAT() & BUSBUSY) {
-		mutex_unlock(&iface->twi_lock);
 		yield();
-		mutex_lock(&iface->twi_lock);
 	}
 
 	iface->writeNum = 0;
@@ -502,9 +490,6 @@ int bfin_twi_smbus_xfer(struct i2c_adapter *adap, u16 addr,
 
 	rc = (iface->result >= 0) ? 0 : -1;
 
-	/* Release mutex */
-	mutex_unlock(&iface->twi_lock);
-
 	return rc;
 }
 
@@ -555,7 +540,6 @@ static int i2c_bfin_twi_probe(struct platform_device *dev)
 	struct i2c_adapter *p_adap;
 	int rc;
 
-	mutex_init(&(iface->twi_lock));
 	spin_lock_init(&(iface->lock));
 	init_completion(&(iface->complete));
 	iface->irq = IRQ_TWI;
-
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