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From:   Julius Werner <jwerner@chromium.org>
Date:   Mon, 24 Feb 2020 17:23:46 -0800
Message-ID: <CAODwPW8WwntWb_=dg2J3AMy-gHw2QvNj_g98SufN13+AuGnUSg@mail.gmail.com>
Subject: Re: [PATCH 1/2] dt-bindings: watchdog: Add arm,smc-wdt watchdog
 arm,smc-wdt compatible
To:     Xingyu Chen <xingyu.chen@amlogic.com>
Cc:     Julius Werner <jwerner@chromium.org>,
        Evan Benn <evanbenn@chromium.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Rob Herring <robh@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, devicetree@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mark Rutland <mark.rutland@arm.com>,
        linux-watchdog@vger.kernel.org,
        Jianxin Pan <jianxin.pan@amlogic.com>,
        Yonghui Yu <yonghui.yu@amlogic.com>
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> 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.

The MediaTek driver is still in flux (e.g. still being reviewed in
Trusted Firmware here:
https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/3405),
we can still change it. So if we can now decide on making this a
"standard" driver, we can change the MediaTek interface to match IMX
and standardize on that. (There are existing Chromebooks shipped with
a different interface, but we could handle those separately with
downstream patches. I think having a unified interface that will
prevent this problem in the future would be worth some extra
complication right now.)