To justify the need for hardware lock, lets take a real usecase scenario - In case of Marvell SoC, PXA910 silicon, both AP and CP are present and these two ARM cores are sharing one pair of I2C pins. In order to keep I2C transaction operated with atomic, hardware lock (RIPC) is required. This patch extends support for atomic operation by adding hardware lock support to the i2c-core. PATCH[1/3] : Core changes for hardware lock PATCH[2/3 & 3/3] : hardware lock support to i2c-pxa bus driver. Link to previous post: http://lkml.iu.edu/hypermail/linux/kernel/1104.3/02352.html http://lkml.iu.edu/hypermail/linux/kernel/1104.3/02353.html http://lkml.iu.edu/hypermail/linux/kernel/1104.3/02354.html TODO: - DT node addition I am using PXA1928 based platform which is still not available in Mainline, so it is based on, below patch-series Link to Rob's patches: https://lkml.org/lkml/2015/5/1/14 https://lkml.org/lkml/2015/5/19/1206 PMIC 88pm860 support http://www.spinics.net/lists/arm-kernel/msg422554.html Vaibhav Hiremath (3): i2c: core: append hardware lock with bus lock i2c: pxa: Add support for hardware lock i2c: pxa: Add pin ctrl support for CP core access drivers/i2c/busses/i2c-pxa.c | 92 ++++++++++++++++++++++++++++++++++++++++++++ drivers/i2c/i2c-core.c | 22 +++++++++-- include/linux/i2c.h | 5 +++ include/linux/i2c/pxa-i2c.h | 4 ++ 4 files changed, 119 insertions(+), 4 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html