Subject: [PATCH v7 5/6] ARM: Exynos: switch to using generic cpufreq driver for exynos4210/5250/5420

From: [email-masked] (Tomasz Figa)
Date: Sat, 19 Jul 2014 15:27:35 +0200

On 14.07.2014 15:38, Thomas Abraham wrote:
> From: Thomas Abraham <[email-masked]>
> 
> Remove the platform device instantiation for exynos cpufreq driver and add the
> platform device for generic cpufreq drivers.
> 
> Cc: Kukjin Kim <[email-masked]>
> Signed-off-by: Thomas Abraham <[email-masked]>
> Acked-by: Viresh Kumar <[email-masked]>
> Reviewed-by: Amit Daniel Kachhap <[email-masked]>
> Tested-by: Arjun K.V <[email-masked]>
> ---
>  arch/arm/mach-exynos/exynos.c |   15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-exynos/exynos.c b/arch/arm/mach-exynos/exynos.c
> index 2a43a17..5028b35 100644
> --- a/arch/arm/mach-exynos/exynos.c
> +++ b/arch/arm/mach-exynos/exynos.c
> @@ -183,7 +183,20 @@ void __init exynos_cpuidle_init(void)
>  
>  void __init exynos_cpufreq_init(void)
>  {
> -	platform_device_register_simple("exynos-cpufreq", -1, NULL, 0);
> +	char *dev_name;
> +
> +	if (of_machine_is_compatible("samsung,exynos5440"))
> +		return;

The original code registers the device unconditionally. Why Exynos5440
is excluded now?

> +	if (of_machine_is_compatible("samsung,exynos5420"))
> +		dev_name = "arm-bL-cpufreq-dt";
> +	else
> +		if (of_machine_is_compatible("samsung,exynos4412") ||
> +			of_machine_is_compatible("samsung,exynos4212"))
> +			dev_name = "exynos-cpufreq";
> +		else
> +			dev_name = "cpufreq-cpu0";
> +
> +	platform_device_register_simple(dev_name, -1, NULL, 0);
>  }

How about rewriting this to:

static const struct of_device_id exynos_cpufreq_matches[] = {
	{ .compatible = "samsung,exynos5420",
			.data = "arm-bL-cpufreq-dt" },
	{ .compatible = "samsung,exynos5250",
			.data = "cpufreq-cpu0" },
	{ .compatible = "samsung,exynos4210",
			.data = "cpufreq-cpu0" },
	{ /* sentinel */ }
};

void __init exynos_cpufreq_init(void)
{
	struct device_node *root = of_find_node_by_path("/");
	const struct of_device_id *match;

	match = of_match_node(exynos_cpufreq_matches, root);
	if (!match) {
		platform_device_register_simple("exynos-cpufreq", -1,
						NULL, 0);
		return;
	}

	platform_device_register_simple(match->data, -1, NULL, 0);
}

This way it is much more readable and original behavior is preserved for
any SoCs not supported by new drivers.

Best regards,
Tomasz