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i2c-algo-pcf: Add adapter hooks around xfer begin and end

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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>
This commit is contained in:
David Miller 2008-10-22 20:21:30 +02:00 committed by Jean Delvare
parent 08e5338d11
commit 30091404af
2 changed files with 16 additions and 4 deletions
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17
drivers/i2c/algos/i2c-algo-pcf.c
View file

@ -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);
}

3
include/linux/i2c-algo-pcf.h
View file

@ -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