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Commit cea443a8 authored by Mike Rapoport's avatar Mike Rapoport Committed by Jean Delvare
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i2c: Support i2c_transfer in atomic contexts 



Allow i2c_transfer to be called in contexts where sleeping is not allowed.
It is the reponsability of the caller to ensure that the underlying i2c bus
driver will not sleep either.

Signed-off-by: default avatarMike Rapoport <mike@compulab.co.il>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 5271071b

drivers/i2c/i2c-core.c

+11 −1
Original line number Diff line number Diff line
@@ -33,6 +33,8 @@ 
#include <linux/platform_device.h>

#include <linux/mutex.h>

#include <linux/completion.h>

#include <linux/hardirq.h>

#include <linux/irqflags.h>

#include <asm/uaccess.h>

#include <asm/semaphore.h>
@@ -861,7 +863,15 @@ int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num) 
		}

#endif



		if (in_atomic() || irqs_disabled()) {

			ret = mutex_trylock(&adap->bus_lock);

			if (!ret)

				/* I2C activity is ongoing. */

				return -EAGAIN;

		} else {

			mutex_lock_nested(&adap->bus_lock, adap->level);

		}



		ret = adap->algo->master_xfer(adap,msgs,num);

		mutex_unlock(&adap->bus_lock);