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Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/i2c-core.c12
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);