linux-kernel - Re: [RFC v1] clk: core: support clocks that need to be enabled during re-parent

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Message-Id: <20190625221415.B0DC22086D@mail.kernel.org>
Date:   Tue, 25 Jun 2019 15:14:14 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Matthias Brugger <matthias.bgg@...il.com>,
        Weiyi Lu <weiyi.lu@...iatek.com>
Cc:     James Liao <jamesjj.liao@...iatek.com>,
        Fan Chen <fan.chen@...iatek.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, linux-clk@...r.kernel.org,
        srv_heupstream@...iatek.com, stable@...r.kernel.org,
        Weiyi Lu <weiyi.lu@...iatek.com>,
        Biao Huang <biao.huang@...iatek.com>
Subject: Re: [RFC v1] clk: core: support clocks that need to be enabled during re-parent

Quoting Weiyi Lu (2019-06-09 20:44:53)
> When using property assigned-clock-parents to assign parent clocks,
> core clocks might still be disabled during re-parent.
> Add flag 'CLK_OPS_CORE_ENABLE' for those clocks must be enabled
> during re-parent.
> 
> Signed-off-by: Weiyi Lu <weiyi.lu@...iatek.com>

Can you further describe the scenario where this is a problem? Is it
some sort of clk that is enabled by default out of the bootloader and is
then configured to have an 'assigned-clock-parents' property to change
the parent, but that clk needs to be "enabled" so that the framework
turns on the parents for the parent switch?