[PATCH 1/2] drivers: amba: properly handle devices with power domains

[Russell King - ARM Linux]

On Wed, Nov 25, 2015 at 01:58:09PM +0100, Marek Szyprowski wrote:
> To read pid/cid registers, the probed device need to be properly turned on.
> When it is inside a power domain, the bus code should ensure that the
> given power domain is enabled before trying to access device's registers.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
> ---
>  drivers/amba/bus.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
> index f009936..25715cb 100644
> --- a/drivers/amba/bus.c
> +++ b/drivers/amba/bus.c
> @@ -373,6 +373,12 @@ int amba_device_add(struct amba_device *dev, struct resource *parent)
>  		goto err_release;
>  	}
>  
> +	ret = dev_pm_domain_attach(&dev->dev, true);
> +	if (ret) {
> +		iounmap(tmp);
> +		goto err_release;
> +	}
> +

NAK.  If dev_pm_domain_attach() returns an error, even -EPROBE_DEFER,
the result will be a missing device that has no way to be recovered.
This is too fragile.

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