i2c-algo-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().

[JD: Make these hooks optional.]

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/i2c/algos/i2c-algo-pcf.c b/drivers/i2c/algos/i2c-algo-pcf.c
index a8a5b6d1dd88..b8a6f3bcbae3 100644
--- a/drivers/i2c/algos/i2c-algo-pcf.c
+++ b/drivers/i2c/algos/i2c-algo-pcf.c
@@ -331,13 +331,16 @@ static int pcf_xfer(struct i2c_adapter *i2c_adap,
         int i;
         int ret=0, timeout, status;
     
+        if (adap->xfer_begin)
+                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 +362,14 @@ 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 +377,8 @@ 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 +410,9 @@ static int pcf_xfer(struct i2c_adapter *i2c_adap,
                 }
         }
 
+out:
+        if (adap->xfer_end)
+                adap->xfer_end(adap->data);
         return (i);
 }