Date: Thu, 21 Aug 2008 02:43:22 -0700 (PDT)
Message-Id: <20080821.024322.35962617.davem@davemloft.net>
To: i2c@lm-sensors.org
CC: khali@linux-fr.org
Subject: [PATCH 2/6]: i2c-pcf: Add adapter hooks around xfer begin and end.
From: David Miller <davem@davemloft.net>
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i2c-pcf: Add adapter hooks around xfer begin and end.

Some I2C bus implementations need to synchronize with external
entities, such as system firmware, which might also be programming the
same I2C bus.

In order to facilitate this add ->xfer_begin() and ->xfer_end() hooks
which are invoked around pcf_xfer().

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/i2c/algos/i2c-algo-pcf.c b/drivers/i2c/algos/i2c-algo-pcf.c
index a8a5b6d..b57bc9a 100644
--- a/drivers/i2c/algos/i2c-algo-pcf.c
+++ b/drivers/i2c/algos/i2c-algo-pcf.c
@@ -331,13 +331,15 @@ static int pcf_xfer(struct i2c_adapter *i2c_adap,
 	int i;
 	int ret=0, timeout, status;
     
+	adap->xfer_begin(adap->data);
 
 	/* Check for bus busy */
 	timeout = wait_for_bb(adap);
 	if (timeout) {
 		DEB2(printk(KERN_ERR "i2c-algo-pcf.o: "
 		            "Timeout waiting for BB in pcf_xfer\n");)
-		return -EIO;
+		i = -EIO;
+		goto out;
 	}
 	
 	for (i = 0;ret >= 0 && i < num; i++) {
@@ -359,12 +361,14 @@ static int pcf_xfer(struct i2c_adapter *i2c_adap,
 		if (timeout) {
 			if (timeout == -EINTR) {
 				/* arbitration lost */
-				return (-EINTR);
+				i = -EINTR;
+				goto out;
 			}
 			i2c_stop(adap);
 			DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting "
 				    "for PIN(1) in pcf_xfer\n");)
-			return (-EREMOTEIO);
+			i = -EREMOTEIO;
+			goto out;
 		}
     
 #ifndef STUB_I2C
@@ -372,7 +376,8 @@ static int pcf_xfer(struct i2c_adapter *i2c_adap,
 		if (status & I2C_PCF_LRB) {
 			i2c_stop(adap);
 			DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)
-			return (-EREMOTEIO);
+			i = -EREMOTEIO;
+			goto out;
 		}
 #endif
     
@@ -404,6 +409,8 @@ static int pcf_xfer(struct i2c_adapter *i2c_adap,
 		}
 	}
 
+out:
+	adap->xfer_end(adap->data);
 	return (i);
 }
 
diff --git a/drivers/i2c/busses/i2c-elektor.c b/drivers/i2c/busses/i2c-elektor.c
index 05f7d09..37bb528 100644
--- a/drivers/i2c/busses/i2c-elektor.c
+++ b/drivers/i2c/busses/i2c-elektor.c
@@ -186,6 +186,14 @@ static int pcf_isa_init(void)
 	return 0;
 }
 
+static void pcf_isa_xfer_begin(void *data)
+{
+}
+
+static void pcf_isa_xfer_end(void *data)
+{
+}
+
 /* ------------------------------------------------------------------------
  * Encapsulate the above functions in the correct operations structure.
  * This is only done when more than one hardware adapter is supported.
@@ -196,6 +204,8 @@ static struct i2c_algo_pcf_data pcf_isa_data = {
 	.getown	    = pcf_isa_getown,
 	.getclock   = pcf_isa_getclock,
 	.waitforpin = pcf_isa_waitforpin,
+	.xfer_begin = pcf_isa_xfer_begin,
+	.xfer_end   = pcf_isa_xfer_end,
 };
 
 static struct i2c_adapter pcf_isa_ops = {
diff --git a/include/linux/i2c-algo-pcf.h b/include/linux/i2c-algo-pcf.h
index 5de8a31..78c62ed 100644
--- a/include/linux/i2c-algo-pcf.h
+++ b/include/linux/i2c-algo-pcf.h
@@ -33,6 +33,9 @@ struct i2c_algo_pcf_data {
 	int  (*getclock) (void *data);
 	void (*waitforpin) (void *data);
 
+	void (*xfer_begin)(void *data);
+	void (*xfer_end)(void *data);
+
 	/* Multi-master lost arbitration back-off delay (msecs)
 	 * This should be set by the bus adapter or knowledgable client
 	 * if bus is multi-mastered, else zero
-- 
1.5.6.5.GIT