Commit 83c42212 authored by Wolfram Sang's avatar Wolfram Sang Committed by Wolfram Sang
Browse files

i2c: core: use I2C locking behaviour also for SMBUS

If I2C transfers are executed in atomic contexts, trylock is used
instead of lock. This behaviour was missing for SMBUS, although a lot of
transfers are of SMBUS type, either emulated or direct. So, factor out
the locking routine into a helper and use it for I2C and SMBUS.
Signed-off-by: default avatarWolfram Sang <>
Reviewed-by Andy Shevchenko <>
Signed-off-by: default avatarWolfram Sang <>
parent bae1d3a0
......@@ -1946,14 +1946,9 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
* one (discarding status on the second message) or errno
* (discarding status on the first one).
if (i2c_in_atomic_xfer_mode()) {
ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
if (!ret)
/* I2C activity is ongoing. */
return -EAGAIN;
} else {
i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
ret = __i2c_lock_bus_helper(adap);
if (ret)
return ret;
ret = __i2c_transfer(adap, msgs, num);
i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
......@@ -20,6 +20,8 @@
#include <linux/i2c-smbus.h>
#include <linux/slab.h>
#include "i2c-core.h"
#include <trace/events/smbus.h>
......@@ -530,7 +532,10 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
s32 res;
i2c_lock_bus(adapter, I2C_LOCK_SEGMENT);
res = __i2c_lock_bus_helper(adapter);
if (res)
return res;
res = __i2c_smbus_xfer(adapter, addr, flags, read_write,
command, protocol, data);
i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
......@@ -39,6 +39,18 @@ static inline bool i2c_in_atomic_xfer_mode(void)
return system_state > SYSTEM_RUNNING && irqs_disabled();
static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)
int ret = 0;
if (i2c_in_atomic_xfer_mode())
ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN;
i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
return ret;
const struct acpi_device_id *
i2c_acpi_match_device(const struct acpi_device_id *matches,
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