soc/amd/stoneyridge/gpio.c: Create I2C slave reset code

AMD's SOC do not wait for I2C transactions to complete before executing
a reset. Because of this, it's possible for the reset to happen in the
middle of a transaction, resulting on a slave hang. There are 2 possible
solutions:
If the slave has a reset pin connected to a GPIO pin, it can be used to
reset the slave, else the only solution is to bang SCL 9 times. Create
code that makes it easy to implement SCL bang, using a devicetree
register to define which I2C SCL lines needs to be reset.

BUG=b:114479395
TEST=Build and boot grunt. Look at transactions on a scope.

Change-Id: I7f74b7e45c509044825355874753969f074e2382
Signed-off-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
Reviewed-on: https://review.coreboot.org/28574
Reviewed-by: Daniel Kurtz <djkurtz@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions