linux-kernel - Re: [PATCH 2/2] soc: imx8: Add cpufreq registering and speed grading check for i.MX8MQ

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Message-ID: <1549975462.2546.30.camel@pengutronix.de>
Date:   Tue, 12 Feb 2019 13:44:22 +0100
From:   Lucas Stach <l.stach@...gutronix.de>
To:     Abel Vesa <abel.vesa@....com>, Anson Huang <anson.huang@....com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>
Cc:     Fabio Estevam <fabio.estevam@....com>,
        dl-linux-imx <linux-imx@....com>, Rob Herring <robh@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/2] soc: imx8: Add cpufreq registering and speed
 grading check for i.MX8MQ

Hi Abel,

Am Dienstag, den 12.02.2019, 12:21 +0000 schrieb Abel Vesa:
> From: Anson Huang <Anson.Huang@....com>
> 
> Register cpu-freq platform driver for i.MX8.
> i.MX8MQ has different parts like consumer, industrial and auto etc.,
> different parts have different cpufreq set-points, this patch adds
> fuse check to select correct cpufreq set-points for each part. The
> default dtb has all set-points available, then kernel will check fuse
> to disable those unused set-points, definition as below:
> 
> OCOTP offset 0x440, bit [7:6]
> 
> '00' - Consumer 0C to 95C
> '01' - Ext. Consumer -20C to 105C
> '10' - Industrial -40C to 105C
> '11' - Automotive -40C to 125C

Shouldn't this read 0x440 [9:8] (SPEED_GRADING) instead? According to
the RM those 2 bits directly encode the maximum ARM core frequency, so
we don't need to guess from the target market.

Regards,
Lucas