[PATCH v2 5/5] lib: utils/reset: Add generic da9063 reset driver

[Heinrich Schuchardt <heinrich.schuchardt@canonical.com>]

On 10/26/21 10:04, Heinrich Schuchardt wrote:
> On 10/15/21 15:19, Nikita Shubin wrote:
>> From: Nikita Shubin <n.shubin@yadro.com>
>>
>> da9063 PMIC can be used to reset/shutdown the
>> Sifive Unmatched board.
>>
>> shutdown is done simply by writing SHUTDOWN bit to
>> DA9063_REG_CONTROL_F register.
>>
>> reset via setting WAKEUP bit in DA9063_REG_CONTROL_F
>> register followed by masking POWER and POWER1 domains
>> and setting STANDBY bit in DA9063_REG_CONTROL_A,
>> originally discovered by Alexandre Ghiti on linux-riscv
>> maillists.
>>
>> Signed-off-by: Nikita Shubin <n.shubin@yadro.com>

Alexandre and I had the same finding for the driver:

Reset works fine after a hard reset (via the reset button) when coming 
from Linux.

After a poweroff reset in U-Boot does not work.

Our expectation is that OpenSBI ensures that the SBI system reset 
extension works upon entry into the next firmware stage without 
requiring any further initialization by that software.

When a reset is requested you should make not presumption about the 
state of the system. Simply fully initialize the da9063 state to 
guarantee a successful reset.

Best regards

Heinrich