linux-kernel - Re: [PATCH v6] drivers: amba: properly handle devices with power domains

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Date:	Tue, 12 Apr 2016 16:49:11 +0200
From:	Ulf Hansson <ulf.hansson@...aro.org>
To:	Marek Szyprowski <m.szyprowski@...sung.com>
Cc:	linux-samsung-soc <linux-samsung-soc@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: Re: [PATCH v6] drivers: amba: properly handle devices with power domains

[...]

>
> +static int __init amba_deferred_device_init(void)
> +{
> +       struct deferred_device *ddev, *tmp;
> +
> +       list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
> +               int ret = amba_device_try_add(ddev->dev, ddev->parent);
> +
> +               if (ret == -EPROBE_DEFER)
> +                       continue;

What happens with devices that still fails to be added here? Should we
schedule a periodic work to re-try?

> +
> +               list_del_init(&ddev->node);
> +               kfree(ddev);
> +       }
> +
> +       return 0;
> +}
> +late_initcall(amba_deferred_device_init);
> +
>  static struct amba_device *
>  amba_aphb_device_add(struct device *parent, const char *name,
>                      resource_size_t base, size_t size, int irq1, int irq2,
> --
> 1.9.2
>

I assume there are other similar buses like AMBA that needs
enumeration before it can bind an appropriate driver for its device.

Perhaps that's a good reason to make this new "device add re-try"
mechanism a generic thing supported by the driver core?

Kind regards
Uffe