i2c: designware: add a new bit check for IC_CON control
authorShyam Sundar S K <Shyam-sundar.S-k@amd.com>
Tue, 24 Jan 2023 11:11:27 +0000 (16:41 +0530)
committerWolfram Sang <wsa@kernel.org>
Sat, 28 Jan 2023 19:05:32 +0000 (20:05 +0100)
commit60a1f9f28660657f863a3846a64b6c3cbb18f07d
tree3855d2cafaa5bb6a39501f906b765254428906e6
parent8786b095df02c1b881643146869a7d6f80411e6a
i2c: designware: add a new bit check for IC_CON control

On some AMD platforms, based on the new designware datasheet,
BIOS sets the BIT(11) within the IC_CON register to advertise
the "bus clear feature capability".

AMD/Designware datasheet says:

Bit(11) BUS_CLEAR_FEATURE_CTRL. Read-write,Volatile. Reset: 0.
Description: In Master mode:
- 1'b1: Bus Clear Feature is enabled.
- 1'b0: Bus Clear Feature is Disabled.
In Slave mode, this register bit is not applicable.

On AMD platform designs:
1. BIOS programs the BUS_CLEAR_FEATURE_CTRL and enables the detection
of SCL/SDA stuck low.
2. Whenever the stuck low is detected, the SMU FW shall do the bus
recovery procedure.

Currently, the way in which the "master_cfg" is built in the driver, it
overrides the BUS_CLEAR_FEATURE_CTRL advertised by BIOS and the SMU FW
cannot initiate the bus recovery if the stuck low is detected.

Hence add a check in i2c_dw_probe_master() that if the BIOS
advertises the bus clear feature, let driver not ignore it and
adapt accordingly.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
drivers/i2c/busses/i2c-designware-core.h
drivers/i2c/busses/i2c-designware-master.c