linux-kernel - Re: [PATCH v1 2/3] clk: starfive: Add StarFive JH7110 PLL clock driver

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Date:   Thu, 23 Feb 2023 10:35:01 +0100
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Xingyu Wu <xingyu.wu@...rfivetech.com>,
        linux-riscv@...ts.infradead.org, devicetree@...r.kernel.org,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Emil Renner Berthing <kernel@...il.dk>
Cc:     Rob Herring <robh+dt@...nel.org>, Conor Dooley <conor@...nel.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Hal Feng <hal.feng@...rfivetech.com>,
        linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org
Subject: Re: [PATCH v1 2/3] clk: starfive: Add StarFive JH7110 PLL clock
 driver

On 23/02/2023 10:32, Xingyu Wu wrote:
> On 2023/2/23 16:56, Krzysztof Kozlowski wrote:
>> On 21/02/2023 15:11, Xingyu Wu wrote:
>>> Add driver for the StarFive JH7110 PLL clock controller and
>>> modify the JH7110 system clock driver to rely on this PLL clocks.
>>>
>>> Signed-off-by: Xingyu Wu <xingyu.wu@...rfivetech.com>
>>> ---
>>
>>
>>> +
>>> +static int jh7110_pll_clk_probe(struct platform_device *pdev)
>>> +{
>>> +	int ret;
>>> +	struct of_phandle_args args;
>>> +	struct regmap *pll_syscon_regmap;
>>> +	unsigned int idx;
>>> +	struct jh7110_clk_pll_priv *priv;
>>> +	struct jh7110_clk_pll_data *data;
>>> +	char *pll_name[JH7110_PLLCLK_END] = {
>>> +		"pll0_out",
>>> +		"pll1_out",
>>> +		"pll2_out"
>>> +	};
>>> +
>>> +	priv = devm_kzalloc(&pdev->dev,
>>> +			    struct_size(priv, data, JH7110_PLLCLK_END),
>>> +			    GFP_KERNEL);
>>> +	if (!priv)
>>> +		return -ENOMEM;
>>> +
>>> +	priv->dev = &pdev->dev;
>>> +	ret = of_parse_phandle_with_fixed_args(pdev->dev.of_node, "starfive,sysreg", 0, 0, &args);
>>
>> 1. Wrong wrapping. Wrap code at 80 as coding style asks.
>>
>> 2. Why you are using syscon for normal, device MMIO operation? Your DTS
>> also points that this is incorrect, hacky representation of hardware.
>> Don't add devices to DT to fake places and then overuse syscon to fix
>> that fake placement. The clock is in system registers, thus it must be
>> there.
>>
>> 3. Even if this stays, why so complicated code instead of
>> syscon_regmap_lookup_by_phandle()?
>>
> 
> Thanks for your advice. Will use syscon_regmap_lookup_by_phandle instead it
> and remove useless part.

So you ignored entirely part 2? This was the main comment... I am going
to keep NAK-ing it then.

Best regards,
Krzysztof