linux-kernel - Re: [PATCH 2/2] clk: imx7d: remove CLK_IS_CRITICAL flag for arm_a7_root

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Message-ID: <153978993915.5275.9461015919945429893@swboyd.mtv.corp.google.com>
Date:   Wed, 17 Oct 2018 08:25:39 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "mturquette@...libre.com" <mturquette@...libre.com>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        Anson Huang <anson.huang@....com>,
        Fabio Estevam <fabio.estevam@....com>
Cc:     dl-linux-imx <linux-imx@....com>
Subject: Re: [PATCH 2/2] clk: imx7d: remove CLK_IS_CRITICAL flag for arm_a7_root_clk

Quoting Anson Huang (2018-10-16 23:12:04)
> i.MX7D uses virtual cpu clock of "arm" clock to be child clock

This statement is concerning. Why do we have virtual clks?

> of "arm_a7_root_clk" and it is with CLK_IS_CRITICAL flag set, so
> no need to add CLK_IS_CRITICAL flag for keeping "arm_a7_root_clk"
> use count correct, latest clock tree is as below in clk_summary:
> 
> pll_arm_main                         1        1        0   792000000          0
>       pll_arm_main_bypass            1        1        0   792000000          0
>          pll_arm_main_clk            1        1        0   792000000          0
>             arm_a7_src               1        1        0   792000000          0
>                arm_a7_cg             1        1        0   792000000          0
>                   arm_a7_div         1        1        0   792000000          0
>                      arm_a7_root_clk       1        1        0   792000000    0
>                         arm          1        1        0   792000000
> 
> Signed-off-by: Anson Huang <Anson.Huang@....com>