Re: [PATCH 1/3] clk: socfpga: agilex: convert to CLK_OF_DECLARE()

[Brian Masney <bmasney@redhat.com>]

Hi Adrian,

On Fri, Sep 11, 2026 at 03:01:18PM +0800, adrian.ho.yin.ng@altera.com wrote:
> From: Adrian Ng Ho Yin <adrian.ho.yin.ng@altera.com>
> 
> Register Agilex and eASIC N5X clocks at of_clk_init() so they are
> available before platform devices probe.
> 
> Signed-off-by: Adrian Ng Ho Yin <adrian.ho.yin.ng@altera.com>
> ---
>  drivers/clk/socfpga/clk-agilex.c | 83 +++++++++++---------------------
>  1 file changed, 28 insertions(+), 55 deletions(-)
> 
> diff --git a/drivers/clk/socfpga/clk-agilex.c b/drivers/clk/socfpga/clk-agilex.c
> index 2bdea1997b5e..64a20c727d16 100644
> --- a/drivers/clk/socfpga/clk-agilex.c
> +++ b/drivers/clk/socfpga/clk-agilex.c
> @@ -4,8 +4,9 @@
>   */
>  #include <linux/slab.h>
>  #include <linux/clk-provider.h>
> +#include <linux/io.h>
>  #include <linux/of.h>
> -#include <linux/platform_device.h>
> +#include <linux/of_address.h>
>  
>  #include <dt-bindings/clock/agilex-clock.h>
>  
> @@ -454,24 +455,26 @@ static int n5x_clk_register_pll(const struct stratix10_pll_clock *clks,
>  	return 0;
>  }
>  
> -static int agilex_clkmgr_init(struct platform_device *pdev)
> +static void __init agilex_clkmgr_init(struct device_node *np)
>  {
> -	struct device_node *np = pdev->dev.of_node;
> -	struct device *dev = &pdev->dev;
>  	struct stratix10_clock_data *clk_data;
>  	void __iomem *base;
>  	int i, num_clks;
>  
> -	base = devm_platform_ioremap_resource(pdev, 0);
> -	if (IS_ERR(base))
> -		return PTR_ERR(base);
> +	base = of_iomap(np, 0);
> +	if (!base) {
> +		pr_err("%s: failed to map clock registers\n", __func__);
> +		return;
> +	}
>  
>  	num_clks = AGILEX_NUM_CLKS;
>  
> -	clk_data = devm_kzalloc(dev, struct_size(clk_data, clk_data.hws,
> -				num_clks), GFP_KERNEL);
> -	if (!clk_data)
> -		return -ENOMEM;
> +	clk_data = kzalloc(struct_size(clk_data, clk_data.hws, num_clks),
> +			   GFP_KERNEL);
> +	if (!clk_data) {
> +		iounmap(base);
> +		return;
> +	}
>  
>  	clk_data->clk_data.num = num_clks;
>  	clk_data->base = base;
> @@ -491,27 +494,28 @@ static int agilex_clkmgr_init(struct platform_device *pdev)
>  	agilex_clk_register_gate(agilex_gate_clks, ARRAY_SIZE(agilex_gate_clks),
>  			      clk_data);
>  	of_clk_add_hw_provider(np, of_clk_hw_onecell_get, &clk_data->clk_data);
> -	return 0;
>  }
>  
> -static int n5x_clkmgr_init(struct platform_device *pdev)
> +static void __init n5x_clkmgr_init(struct device_node *np)
>  {
> -	struct device_node *np = pdev->dev.of_node;
> -	struct device *dev = &pdev->dev;
>  	struct stratix10_clock_data *clk_data;
>  	void __iomem *base;
>  	int i, num_clks;
>  
> -	base = devm_platform_ioremap_resource(pdev, 0);
> -	if (IS_ERR(base))
> -		return PTR_ERR(base);
> +	base = of_iomap(np, 0);
> +	if (!base) {
> +		pr_err("%s: failed to map clock registers\n", __func__);
> +		return;
> +	}
>  
>  	num_clks = AGILEX_NUM_CLKS;
>  
> -	clk_data = devm_kzalloc(dev, struct_size(clk_data, clk_data.hws,
> -				num_clks), GFP_KERNEL);
> -	if (!clk_data)
> -		return -ENOMEM;
> +	clk_data = kzalloc(struct_size(clk_data, clk_data.hws, num_clks),
> +			   GFP_KERNEL);
> +	if (!clk_data) {
> +		iounmap(base);
> +		return;
> +	}
>  
>  	clk_data->base = base;
>  	clk_data->clk_data.num = num_clks;
> @@ -531,38 +535,7 @@ static int n5x_clkmgr_init(struct platform_device *pdev)
>  	agilex_clk_register_gate(agilex_gate_clks, ARRAY_SIZE(agilex_gate_clks),
>  			      clk_data);
>  	of_clk_add_hw_provider(np, of_clk_hw_onecell_get, &clk_data->clk_data);
> -	return 0;
> -}
> -
> -static int agilex_clkmgr_probe(struct platform_device *pdev)
> -{
> -	int (*probe_func)(struct platform_device *init_func);
> -
> -	probe_func = of_device_get_match_data(&pdev->dev);
> -	if (!probe_func)
> -		return -ENODEV;
> -	return	probe_func(pdev);
>  }
>  
> -static const struct of_device_id agilex_clkmgr_match_table[] = {
> -	{ .compatible = "intel,agilex-clkmgr",
> -	  .data = agilex_clkmgr_init },
> -	{ .compatible = "intel,easic-n5x-clkmgr",
> -	  .data = n5x_clkmgr_init },
> -	{ }
> -};
> -
> -static struct platform_driver agilex_clkmgr_driver = {
> -	.probe		= agilex_clkmgr_probe,
> -	.driver		= {
> -		.name	= "agilex-clkmgr",
> -		.suppress_bind_attrs = true,
> -		.of_match_table = agilex_clkmgr_match_table,
> -	},
> -};
> -
> -static int __init agilex_clk_init(void)
> -{
> -	return platform_driver_register(&agilex_clkmgr_driver);
> -}
> -core_initcall(agilex_clk_init);
> +CLK_OF_DECLARE(agilex_clkmgr, "intel,agilex-clkmgr", agilex_clkmgr_init);
> +CLK_OF_DECLARE(n5x_clkmgr, "intel,easic-n5x-clkmgr", n5x_clkmgr_init);

Why do all of these clk providers need to be registered so early?
CLK_OF_DECLARE is abused quite a bit today and the majority of the clk
drivers that use it don't actually need it.

core_initcall() is pretty early as well. Can you use subsys_initcall
instead so that it's available by time the platform devices probe?

I recently introduced a subsys_platform_driver() macro to simplify the
code that should do what you need.

https://lore.kernel.org/linux-clk/20260908-subsys_initcall-v1-0-cbccf4cd4288@redhat.com/

Brian