linux-kernel - Re: [PATCH v2 2/3] clk: conf: Support assigned-clock-sscs

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Message-ID: <aLdmXcdJnoeXEJaQ@x1>
Date: Tue, 2 Sep 2025 17:49:17 -0400
From: Brian Masney <bmasney@...hat.com>
To: Peng Fan <peng.fan@....com>
Cc: Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>,
	Sudeep Holla <sudeep.holla@....com>,
	Cristian Marussi <cristian.marussi@....com>,
	Marco Felsch <m.felsch@...gutronix.de>,
	Dan Carpenter <dan.carpenter@...aro.org>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
	arm-scmi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 2/3] clk: conf: Support assigned-clock-sscs

On Mon, Sep 01, 2025 at 11:51:46AM +0800, Peng Fan wrote:
> Parse the Spread Spectrum Configuration(SSC) from device tree and configure
> them before using the clock.
> 
> Each SSC is three u32 elements which means '<modfreq spreaddepth
> modmethod>', so assigned-clock-sscs is an array of multiple three u32
> elements.
> 
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>  drivers/clk/clk-conf.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 69 insertions(+)
> 
> diff --git a/drivers/clk/clk-conf.c b/drivers/clk/clk-conf.c
> index 303a0bb26e54a95655ce094a35b989c97ebc6fd8..dd6083597db3f8f27d86abf5640dfc3fb39a9b88 100644
> --- a/drivers/clk/clk-conf.c
> +++ b/drivers/clk/clk-conf.c
> @@ -155,6 +155,71 @@ static int __set_clk_rates(struct device_node *node, bool clk_supplier)
>  	return 0;
>  }
>  
> +static int __set_clk_spread_spectrum(struct device_node *node, bool clk_supplier)
> +{
> +	struct clk_spread_spectrum *sscs __free(kfree) = NULL;
> +	u32 elem_size = sizeof(struct clk_spread_spectrum);
> +	struct of_phandle_args clkspec;
> +	int rc, count, index;
> +	struct clk *clk;
> +
> +	/* modfreq, spreadPercent, modmethod */
> +	count = of_property_count_elems_of_size(node, "assigned-clock-sscs", elem_size);
> +	if (count <= 0)
> +		return 0;
> +
> +	sscs = kcalloc(count, elem_size, GFP_KERNEL);
> +	if (!sscs)
> +		return -ENOMEM;
> +
> +	rc = of_property_read_u32_array(node, "assigned-clock-sscs", (u32 *)sscs,
> +					count * 3);
> +	if (rc)
> +		return rc;
> +
> +	for (index = 0; index < count; index++) {
> +		struct clk_spread_spectrum *conf = &sscs[index];
> +		struct clk_hw *hw;
> +
> +		if (!conf->modfreq_hz && !conf->spread_bp && !conf->method)
> +			continue;
> +
> +		rc = of_parse_phandle_with_args(node, "assigned-clocks", "#clock-cells",
> +						index, &clkspec);
> +		if (rc < 0) {
> +			/* skip empty (null) phandles */
> +			if (rc == -ENOENT)
> +				continue;
> +			else
> +				return rc;
> +		}
> +
> +		if (clkspec.np == node && !clk_supplier) {
> +			of_node_put(clkspec.np);
> +			return 0;
> +		}
> +
> +		clk = of_clk_get_from_provider(&clkspec);
> +		of_node_put(clkspec.np);
> +		if (IS_ERR(clk)) {
> +			if (PTR_ERR(clk) != -EPROBE_DEFER)
> +				pr_warn("clk: couldn't get clock %d for %pOF\n",
> +					index, node);
> +			return PTR_ERR(clk);

This chunk can be replaced with dev_warn_probe(). Sorry I missed that in
v1. Otherwise the rest looks good to me. With that fixed:

Reviewed-by: Brian Masney <bmasney@...hat.com>