[SRU][N:linux-bluefield][PATCH v1 0/2] UBUNTU: SAUCE: i2c-mlxbf: Repeated start support

[Chris Babroski]

BugLink: https://bugs.launchpad.net/bugs/2115650

[Impact]

Reading SMBus or I2C block data on Bluefield will fail if the target device requires repeated
start conditions to be used. This support has been added on Ubuntu Jammy for 22.04, but is
missing on Ubuntu Noble 24.04 release. Port the patches that were accepted into upstream
linux-next kernel branch for Ubuntu 24.04.

[Fix]

* Add support for repeated start conditions to the Mellanox I2C driver.
* Enable repeated start condition for I2C_FUNC_SMBUS_WRITE_I2C_BLOCK read implementation.
* Update I2C bus timing settings based on latest HW testing results. Required for repeated start
  transactions with Bluefield 3 target devices.

[Test Case]

* Verified MLXBF I2C driver builds and loads without errors on Bluefield 2 and Bluefield 3.
* Verified I2C block read of a device that requires repeated start conditions succeeds using
  the following command: "i2cget -y <bus> <target> <reg> i <bytes>".
* Verified IPMB communication with BMC to regression test general I2C behavior. Used to following
  command which will result in several I2C transactions: "ipmitool mc info".

[Regression Potential]

* I2C bus timing settings have been updated and will affect all I2C and SMBus transactions on
  Bluefield.
* SMBus I2C block reads now include a repeated start condition which could cause a regression if
  this type of read is expected to be used with a target device that does not support repeated
  start conditions.
* IPMB transactions that use I2C could fail due to a bug with this implementation.

Chris Babroski (2):
  [SRU][N:linux-bluefield][PATCH v1 1/2] UBUNTU: SAUCE: i2c-mlxbf:
    Repeated start support
  [SRU][N:linux-bluefield][PATCH v1 2/2] UBUNTU: SAUCE: i2c-mlxbf:
    Improve I2C bus timing configuration

 drivers/i2c/busses/i2c-mlxbf.c | 68 +++++++++++++++++++++-------------
 1 file changed, 42 insertions(+), 26 deletions(-)

-- 
2.34.1