linux-kernel - Re: [PATCH RFC 4/8] soc: samsung: Add Exynos Adaptive Supply Voltage driver

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Message-ID: <1d2238be-1758-2413-42f1-d571706de766@samsung.com>
Date:   Wed, 24 Apr 2019 10:11:07 +0200
From:   Sylwester Nawrocki <s.nawrocki@...sung.com>
To:     Krzysztof Kozlowski <krzk@...nel.org>
Cc:     kgene@...nel.org, robh+dt@...nel.org, mark.rutland@....com,
        Chanwoo Choi <cw00.choi@...sung.com>, myungjoo.ham@...sung.com,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        pankaj.dubey@...sung.com,
        Bartłomiej Żołnierkiewicz 
        <b.zolnierkie@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH RFC 4/8] soc: samsung: Add Exynos Adaptive Supply
 Voltage driver

On 4/23/19 12:50, Krzysztof Kozlowski wrote:
>> +static int exynos5422_asv_get_table(void)
>> +{
>> +       unsigned int reg = exynos_chipid_read(EXYNOS_CHIPID_REG_PKG_ID);
>
> One more thought: you read this register multiple times in the same
> function. I think it is not needed - just read once, store the value
> and use the helpers to parse it.

Yes, I have noticed that as well. I'm not sure though if it is worth 
to additionally cache registers manually like this when we use the 
regmap.  I have already converted that code to use the regmap API for 
v2.  And these are barely few registers reads at the driver 
initialization time, not any hot path.

-- 
Thanks,
Sylwester