Re: [PATCH] cpufreq-cpu0: support Device Tree initialisation

[Nishanth Menon <nm@ti.com>]

On 07/26/2013 05:19 AM, Guennadi Liakhovetski wrote:
> Currently the cpufreq-cpu0 driver doesn't support Device Tree probing. To
> support it we add an OF match table to it. In principle this alone is
> enough to get the driver working with DT devices, but then the driver
> rewrites the .of_node field of the probed device with a different one,
> which isn't clean. To avoid this we use the cpu0 system device for clock
> and OPP handling, similar to what the arm_big_little CPUFreq driver does.
> This is also less intrusive, since the cpu0 device's .of_node field is
> initially NULL, since this isn't a DT device.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
> ---
>   drivers/cpufreq/cpufreq-cpu0.c |   14 +++++++++++---
>   1 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
> index ad1fde2..d2ad7b8 100644
> --- a/drivers/cpufreq/cpufreq-cpu0.c
> +++ b/drivers/cpufreq/cpufreq-cpu0.c
> @@ -12,6 +12,7 @@
>   #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
>
>   #include <linux/clk.h>
> +#include <linux/cpu.h>
>   #include <linux/cpufreq.h>
>   #include <linux/err.h>
>   #include <linux/module.h>
> @@ -194,7 +195,7 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev)
>   		goto out_put_parent;
>   	}
>
> -	cpu_dev = &pdev->dev;
> +	cpu_dev = get_cpu_device(0);
>   	cpu_dev->of_node = np;
>
>   	cpu_reg = devm_regulator_get(cpu_dev, "cpu0");
> @@ -289,10 +290,17 @@ static int cpu0_cpufreq_remove(struct platform_device *pdev)
>   	return 0;
>   }
>
> +static const struct of_device_id cpu0_cpufreq_of_match[] = {
> +	{.compatible = "cpufreq-cpu0"},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, cpu0_cpufreq_of_match);
> +
>   static struct platform_driver cpu0_cpufreq_platdrv = {
>   	.driver = {
> -		.name	= "cpufreq-cpu0",
> -		.owner	= THIS_MODULE,
> +		.name		= "cpufreq-cpu0",
> +		.of_match_table	= cpu0_cpufreq_of_match,
> +		.owner		= THIS_MODULE,
>   	},
>   	.probe		= cpu0_cpufreq_probe,
>   	.remove		= cpu0_cpufreq_remove,
>
Did we not go down this approach[1] previously? Could you explain why 
this path is different now?


[1] http://marc.info/?t=136304320700004&r=1&w=2
-- 
Regards,
Nishanth Menon