linux-kernel - Re: [PATCH net-next] driver: cadence macb driver support acpi mode

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Message-ID: <YwZA+1z7BDCXZn/3@lunn.ch>
Date:   Wed, 24 Aug 2022 17:17:15 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     "xiaowu.ding" <xiaowu.ding@...uarmicro.com>
Cc:     davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        pabeni@...hat.com, linux@...linux.org.uk,
        nicolas.ferre@...rochip.com, claudiu.beznea@...rochip.com,
        palmer@...belt.com, paul.walmsley@...ive.com,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-riscv@...ts.infradead.org
Subject: Re: [PATCH net-next] driver: cadence macb driver support acpi mode

> +/* On ACPI platforms, clocks are controlled by firmware and/or
> + * ACPI, not by drivers.Need to store the clock value.
> + */
> +struct macb_acpi_config {
> +	u32 hclk_rate;          /* amba clock rate*/
> +	u32 pclk_rate;          /* amba apb clock rate*/
> +	u32 txclk_rate;         /* tx clock rate*/
> +	u32 rxclk_rate;         /* rx clock rate*/
> +	u32 tsuclk_rate;        /* tx clock rate*/
> +	bool acpi_enable;       /* is acpi or not */
> +};

> +static int macb_acpi_support(struct macb *bp)
> +{
> +	struct device *dev = &bp->pdev->dev;
> +	struct macb_acpi_config *config = &bp->acpicfg;
> +	int ret;
> +	u32 property;
> +
> +	/*acpi must be report the pclk*/
> +	property = 0;
> +	ret = device_property_read_u32(dev, MACB_SYSPCLOCK, &property);
> +	if (ret) {
> +		dev_err(dev, "unable to obtain %s property\n", MACB_SYSPCLOCK);
> +		return ret;
> +	}
> +
> +	config->pclk_rate = property;

It seems like you could make this simpler by just calling

clk_hw_register_fixed_rate(dev, "pclk", NULL, 0, property);

You then don't need to modify any other code with respect to clocks.
The clock does exist, so model it in the common clock framework.

    Andrew