linux-kernel - Re: [PATCH 1/2] device property: Check fwnode->secondary in fwnode_graph_get_next

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Date:   Fri, 30 Jul 2021 14:34:31 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Daniel Scally <djrscally@...il.com>
Cc:     linux-kernel@...r.kernel.org, gregkh@...uxfoundation.org,
        rafael@...nel.org, laurent.pinchart@...asonboard.com
Subject: Re: [PATCH 1/2] device property: Check fwnode->secondary in
 fwnode_graph_get_next_endpoint()

On Fri, Jul 23, 2021 at 02:04:59PM +0100, Daniel Scally wrote:
> 
> On 23/07/2021 13:32, Andy Shevchenko wrote:
> > On Thu, Jul 22, 2021 at 09:19:28PM +0100, Daniel Scally wrote:
> >> Sensor drivers often check for an endpoint to make sure that they're
> >> connected to a consuming device like a CIO2 during .probe(). Some of
> >> those endpoints might be in the form of software_nodes assigned as
> >> a secondary to the device's fwnode_handle. Account for this possibility
> >> in fwnode_graph_get_next_endpoint() to avoid having to do it in the
> >> sensor drivers themselves.
> > ...
> >
> >> +	ep = fwnode_call_ptr_op(parent, graph_get_next_endpoint, prev);
> >> +
> >> +	if (IS_ERR_OR_NULL(ep) && !IS_ERR_OR_NULL(parent) &&
> >> +	    !IS_ERR_OR_NULL(parent->secondary))
> > Nit-pick, I would put it like:
> >
> > 	if (!IS_ERR_OR_NULL(parent->secondary) && !IS_ERR_OR_NULL(parent) &&
> > 	    IS_ERR_OR_NULL(ep))
> >
> > or
> >
> > 	if (IS_ERR_OR_NULL(ep) &&
> > 	    !IS_ERR_OR_NULL(parent->secondary) && !IS_ERR_OR_NULL(parent))
> >
> > for the sake of logical split.
> 
> 
> OK; I'll do the second one, feel like it's better to have ep as the
> first check.

Fine, but also I have just noticed that parent should be checked before
parent->secondary.

Something like this

	if (IS_ERR_OR_NULL(ep) &&
	    !IS_ERR_OR_NULL(parent) && IS_ERR_OR_NULL(parent->secondary))

> >> +		ep = fwnode_graph_get_next_endpoint(parent->secondary, NULL);

-- 
With Best Regards,
Andy Shevchenko