diff options
| -rw-r--r-- | drivers/i2c/i2c-core.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 7161f913de1..ddd1b83f44d 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -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 - mutex_lock_nested(&adap->bus_lock, adap->level); + 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); |