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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 <wsa+renesas@sang-engineering.com>
Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent bae1d3a0

drivers/i2c/i2c-core-base.c

+3 −8
Original line number Diff line number Diff line
@@ -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);

drivers/i2c/i2c-core-smbus.c

+6 −1
Original line number Diff line number Diff line
@@ -20,6 +20,8 @@ 
#include <linux/i2c-smbus.h>

#include <linux/slab.h>



#include "i2c-core.h"



#define CREATE_TRACE_POINTS

#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);

drivers/i2c/i2c-core.h

+12 −0
Original line number Diff line number Diff line
@@ -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;

	else

		i2c_lock_bus(adap, I2C_LOCK_SEGMENT);



	return ret;

}



#ifdef CONFIG_ACPI

const struct acpi_device_id *

i2c_acpi_match_device(const struct acpi_device_id *matches,