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, once the base dts file gets merged, will submit patch
for I2C support. Hopefully by that time I should have PMIC client driver
support available.
Link to Rob's patches:
https://lkml.org/lkml/2015/5/1/14
https://lkml.org/lkml/2015/5/19/1206
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
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