linux-kernel - Re: [PATCH 3/3] cpufreq: imx-sc: add i.mx system controller cpufreq support

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Message-ID: <20190213070904.3oswrjafy6cqedsr@vireshk-i7>
Date:   Wed, 13 Feb 2019 12:39:04 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Anson Huang <anson.huang@....com>
Cc:     "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        "catalin.marinas@....com" <catalin.marinas@....com>,
        "will.deacon@....com" <will.deacon@....com>,
        "rjw@...ysocki.net" <rjw@...ysocki.net>,
        Aisheng Dong <aisheng.dong@....com>,
        Daniel Baluta <daniel.baluta@....com>,
        Andy Gross <andy.gross@...aro.org>,
        "horms+renesas@...ge.net.au" <horms+renesas@...ge.net.au>,
        "heiko@...ech.de" <heiko@...ech.de>,
        "arnd@...db.de" <arnd@...db.de>,
        "bjorn.andersson@...aro.org" <bjorn.andersson@...aro.org>,
        "jagan@...rulasolutions.com" <jagan@...rulasolutions.com>,
        "enric.balletbo@...labora.com" <enric.balletbo@...labora.com>,
        "marc.w.gonzalez@...e.fr" <marc.w.gonzalez@...e.fr>,
        "olof@...om.net" <olof@...om.net>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>
Subject: Re: [PATCH 3/3] cpufreq: imx-sc: add i.mx system controller cpufreq
 support

On 13-02-19, 03:09, Anson Huang wrote:
> On NXP's i.MX SoCs with system controller inside, CPU frequency
> scaling can ONLY be done by system controller firmware, and it
> can ONLY be requested from secure mode, so Linux cpufreq driver has
> to call ARM SMC to trap to ARM-Trusted-Firmware to request system
> controller firmware to do CPU frequency scaling.
> 
> This patch adds i.MX system controller cpufreq driver support,
> when doing CPU frequency scaling, cpufreq driver will do ARM SMC
> call and trap to ARM-Trusted-Firmware, then SIP(silicon provider)
> service will communicate with system controller for CPU frequenct
> scaling.
> 
> Signed-off-by: Anson Huang <Anson.Huang@....com>
> ---
>  drivers/cpufreq/Kconfig.arm      |   9 ++
>  drivers/cpufreq/Makefile         |   1 +
>  drivers/cpufreq/imx-sc-cpufreq.c | 183 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 193 insertions(+)
>  create mode 100644 drivers/cpufreq/imx-sc-cpufreq.c

Why can't you use cpufreq-dt driver like everyone else ?

-- 
viresh