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Commit 30091404 authored by David Miller's avatar David Miller Committed by Jean Delvare
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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: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 08e5338d

drivers/i2c/algos/i2c-algo-pcf.c

+13 −4
Original line number Original line Diff line number Diff line
@@ -331,13 +331,16 @@ static int pcf_xfer(struct i2c_adapter *i2c_adap, 
	int i;

	int i;

	int ret=0, timeout, status;

	int ret=0, timeout, status;

    

    

	if (adap->xfer_begin)

		adap->xfer_begin(adap->data);





	/* Check for bus busy */

	/* Check for bus busy */

	timeout = wait_for_bb(adap);

	timeout = wait_for_bb(adap);

	if (timeout) {

	if (timeout) {

		DEB2(printk(KERN_ERR "i2c-algo-pcf.o: "

		DEB2(printk(KERN_ERR "i2c-algo-pcf.o: "

		            "Timeout waiting for BB in pcf_xfer\n");)

		            "Timeout waiting for BB in pcf_xfer\n");)

		return -EIO;

		i = -EIO;

		goto out;

	}

	}

	

	

	for (i = 0;ret >= 0 && i < num; i++) {

	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) {

			if (timeout == -EINTR) {

			if (timeout == -EINTR) {

				/* arbitration lost */

				/* arbitration lost */

				return (-EINTR);

				i = -EINTR;

				goto out;

			}

			}

			i2c_stop(adap);

			i2c_stop(adap);

			DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting "

			DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting "

				    "for PIN(1) in pcf_xfer\n");)

				    "for PIN(1) in pcf_xfer\n");)

			return (-EREMOTEIO);

			i = -EREMOTEIO;

			goto out;

		}

		}

    

    

#ifndef STUB_I2C

#ifndef STUB_I2C
@@ -372,7 +377,8 @@ static int pcf_xfer(struct i2c_adapter *i2c_adap, 
		if (status & I2C_PCF_LRB) {

		if (status & I2C_PCF_LRB) {

			i2c_stop(adap);

			i2c_stop(adap);

			DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)

			DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)

			return (-EREMOTEIO);

			i = -EREMOTEIO;

			goto out;

		}

		}

#endif

#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);

	return (i);

}

}

include/linux/i2c-algo-pcf.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -33,6 +33,9 @@ struct i2c_algo_pcf_data { 
	int  (*getclock) (void *data);

	int  (*getclock) (void *data);

	void (*waitforpin) (void *data);

	void (*waitforpin) (void *data);





	void (*xfer_begin) (void *data);

	void (*xfer_end) (void *data);



	/* Multi-master lost arbitration back-off delay (msecs)

	/* Multi-master lost arbitration back-off delay (msecs)

	 * This should be set by the bus adapter or knowledgable client

	 * This should be set by the bus adapter or knowledgable client

	 * if bus is multi-mastered, else zero

	 * if bus is multi-mastered, else zero