linux-kernel - Re: [PATCH v3 2/2] clk: clk-conf: support assigned-clock-rates-u64

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Message-ID: <08ed1ae35b69e11e69ce178af41c77b0.sboyd@kernel.org>
Date: Wed, 31 Jul 2024 15:23:57 -0700
From: Stephen Boyd <sboyd@...nel.org>
To: Luca Ceresoli <luca.ceresoli@...tlin.com>, Michael Turquette <mturquette@...libre.com>, Peng Fan (OSS) <peng.fan@....nxp.com>, Rob Herring <robh@...nel.org>, Saravana Kannan <saravanak@...gle.com>
Cc: devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org, Peng Fan <peng.fan@....com>
Subject: Re: [PATCH v3 2/2] clk: clk-conf: support assigned-clock-rates-u64

Quoting Peng Fan (OSS) (2024-07-30 01:57:55)
> From: Peng Fan <peng.fan@....com>
> 
> i.MX95 System Management Control Firmware(SCMI) manages the clock
> function, it exposes PLL VCO which could support up to 5GHz rate that
> exceeds UINT32_MAX. So add assigned-clock-rates-u64 support
> to set rate that exceeds UINT32_MAX.
> 
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>  drivers/clk/clk-conf.c | 42 +++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 37 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/clk/clk-conf.c b/drivers/clk/clk-conf.c
> index 058420562020..684e0c0738b3 100644
> --- a/drivers/clk/clk-conf.c
> +++ b/drivers/clk/clk-conf.c
> @@ -81,11 +81,44 @@ static int __set_clk_parents(struct device_node *node, bool clk_supplier)
>  static int __set_clk_rates(struct device_node *node, bool clk_supplier)
>  {
>         struct of_phandle_args clkspec;
> -       int rc, index = 0;
> +       int rc, count, index;
>         struct clk *clk;
> -       u32 rate;
> +       u32 *rates __free(kfree);
> +       bool rate_64 = false;
> +
> +       count = of_property_count_u64_elems(node, "assigned-clock-rates-u64");
> +       if (count <= 0) {
> +               count = of_property_count_u32_elems(node, "assigned-clock-rates");
> +               if (count <= 0)
> +                       return 0;
> +
> +               rates = kcalloc(count, sizeof(u32), GFP_KERNEL);
> +               if (!rates)
> +                       return -ENOMEM;
> +               rc = of_property_read_variable_u32_array(node,
> +                                                        "assigned-clock-rates",
> +                                                        rates,
> +                                                        1, count);
> +       } else {
> +               rates = kcalloc(count, sizeof(u64), GFP_KERNEL);
> +               if (!rates)
> +                       return -ENOMEM;
> +               rc = of_property_read_variable_u64_array(node,
> +                                                        "assigned-clock-rates-u64",
> +                                                        (u64 *)rates,
> +                                                        1, count);
> +               rate_64 = true;
> +       }

Can this be less indented somehow?

	u64 *rates_64 __free(kfree) = NULL;
	u32 *rates __free(kfree) = NULL;
	int count_64, count;

	count = of_property_count_u32_elems(node, "assigned-clock-rates");
	count_64 = of_property_count_u64_elems(node, "assigned-clock-rates-u64");
	if (count_64 > 0) {
		count = count_64;
		rates_64 = kcalloc(count, sizeof(*rates_64), GFP_KERNEL);
		if (!rates_64)
			return -ENOMEM;

		rc = of_property_read_u64_array(node,
						"assigned-clock-rates-u64",
						rates_64, count);
	} else if (count > 0) {
		rates = kcalloc(count, sizeof(*rates), GFP_KERNEL));
		if (!rates)
			return -ENOMEM;

		rc = of_property_read_u32_array(node, "assigned-clock-rates",
						rates, count);
	} else {
		return 0;
	}
	
	if (rc)
		return rc;

	for (index = 0; index < count; index++) {
		unsigned long rate;

		if (rates_64)
			rate = rates_64[index];
		else
			rate = rates[index];

> +
> +
> +       for (index = 0; index < count; index++) {
> +               unsigned long rate;
> +
> +               if (rate_64)
> +                       rate = ((u64 *)rates)[index];

Please no casts.

> +               else
> +                       rate = rates[index];
>