Re: [PATCH 1/2] dt-bindings: watchdog: Add arm,smc-wdt watchdog arm,smc-wdt compatible

From: Xingyu Chen
Date: Fri Feb 21 2020 - 23:02:37 EST

Hi, Julius

On 2020/2/22 3:41, Julius Werner wrote:
Because the ATF does not define standard wdt index, each vendor defines
its own index.
So I don't think that the current driver[0] can fully cover my usecases.
I think the best way to solve this would be to put the SMC function ID
as another field into the device tree, so that multiple vendors could
share the same driver even if their firmware interface uses a
different SMC. But they still have to implement the same API for that
SMC, of course, not sure if the Meson driver is suitable for that (but
if it is then I think merging those drivers would be a good idea).
The SMC function ID may be solved by the DTS, but the wdt indexs(Eg: SMCWD_INFO) are also different
for each vendor. The imx_sc_wdt.c is also use the SMC to operate the WDT, but the wdt indexs(Eg: IMX_SIP_TIMER_START_WDOG)
are different from ours. IMO, If the ATF can implement a common hal interface and index for watchdog, then writing a
common smc wdt driver will be easier to compatible with all vendors.

Best Regards