linux-kernel - Re: [PATCH 1/1] mfd: mfd-core: Honour Device Tree's request to disable a child-device

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Date:   Thu, 7 Nov 2019 11:54:56 +0000
From:   Daniel Thompson <daniel.thompson@...aro.org>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     broonie@...nel.org, arnd@...db.de, linus.walleij@...aro.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        baohua@...nel.org, stephan@...hold.net,
        Barry Song <Baohua.Song@....com>
Subject: Re: [PATCH 1/1] mfd: mfd-core: Honour Device Tree's request to
 disable a child-device

On Thu, Nov 07, 2019 at 11:19:50AM +0000, Lee Jones wrote:
> Until now, MFD has assumed all child devices passed to it (via
> mfd_cells) are to be registered. It does not take into account
> requests from Device Tree and the like to disable child devices
> on a per-platform basis.
> 
> Well now it does.
> 
> Link: https://www.spinics.net/lists/arm-kernel/msg366309.html
> Link: https://lkml.org/lkml/2019/8/22/1350
> 
> Reported-by: Barry Song <Baohua.Song@....com>
> Reported-by: Stephan Gerhold <stephan@...hold.net>
> Signed-off-by: Lee Jones <lee.jones@...aro.org>

Reviewed-by: Daniel Thompson <daniel.thompson@...aro.org>

> ---
>  drivers/mfd/mfd-core.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
> index cb3e0a14bbdd..f5a73af60dd4 100644
> --- a/drivers/mfd/mfd-core.c
> +++ b/drivers/mfd/mfd-core.c
> @@ -152,6 +152,11 @@ static int mfd_add_device(struct device *parent, int id,
>  	if (parent->of_node && cell->of_compatible) {
>  		for_each_child_of_node(parent->of_node, np) {
>  			if (of_device_is_compatible(np, cell->of_compatible)) {
> +				if (!of_device_is_available(np)) {
> +					/* Ignore disabled devices error free */
> +					ret = 0;
> +					goto fail_alias;
> +				}
>  				pdev->dev.of_node = np;
>  				pdev->dev.fwnode = &np->fwnode;
>  				break;
> -- 
> 2.24.0
>