linux-kernel - Re: [PATCH v2] software_node: Add support for fwnode

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Date:   Fri, 18 Sep 2020 09:22:38 +0300
From:   Sakari Ailus <sakari.ailus@....fi>
To:     Dan Scally <djrscally@...il.com>
Cc:     gregkh@...uxfoundation.org, rafael@...nel.org,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        heikki.krogerus@...ux.intel.com, andriy.shevchenko@...ux.intel.com,
        kieran.bingham@...asonboard.com, jorhand@...ux.microsoft.com,
        kitakar@...il.com
Subject: Re: [PATCH v2] software_node: Add support for fwnode_graph*() family
 of functions

Hi Dan,

On Wed, Sep 16, 2020 at 02:22:10PM +0100, Dan Scally wrote:
> Hi Sakari - thanks for the comments
> 
> On 16/09/2020 10:17, Sakari Ailus wrote:
> > Moi Daniel and Heikki,
> >
> > On Wed, Sep 16, 2020 at 12:28:27AM +0100, Daniel Scally wrote:
> >> From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> >>
> >> This implements the remaining .graph_* callbacks in the
> >> fwnode operations vector for the software nodes. That makes
> >> the fwnode_graph*() functions available in the drivers also
> >> when software nodes are used.
> >>
> >> The implementation tries to mimic the "OF graph" as much as
> >> possible, but there is no support for the "reg" device
> >> property. The ports will need to have the index in their
> >> name which starts with "port" (for example "port0", "port1",
> >> ...) and endpoints will use the index of the software node
> >> that is given to them during creation. The port nodes can
> >> also be grouped under a specially named "ports" subnode,
> >> just like in DT, if necessary.
> >>
> >> The remote-endpoints are reference properties under the
> >> endpoint nodes that are named "remote-endpoint". 
> >>
> >> Signed-off-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> >> Co-developed-by: Daniel Scally <djrscally@...il.com>
> >> Signed-off-by: Daniel Scally <djrscally@...il.com>
> >> ---
> >> changes in v2:
> >> 	- added software_node_device_is_available
> >> 	- altered software_node_get_next_child to get references
> >> 	- altered software_node_get_next_endpoint to release references
> >> 	to ports and avoid passing invalid combinations of swnodes to
> >> 	software_node_get_next_child
> >> 	- altered swnode_graph_find_next_port to release port rather than
> >> 	old
> >> 	
> >>  drivers/base/swnode.c | 129 +++++++++++++++++++++++++++++++++++++++++-
> >>  1 file changed, 127 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
> >> index 010828fc785b..d69034b807e3 100644
> >> --- a/drivers/base/swnode.c
> >> +++ b/drivers/base/swnode.c
> >> @@ -363,6 +363,11 @@ static void software_node_put(struct fwnode_handle *fwnode)
> >>  	kobject_put(&swnode->kobj);
> >>  }
> >>  
> >> +static bool software_node_device_is_available(const struct fwnode_handle *fwnode)
> >> +{
> >> +	return is_software_node(fwnode);
> > This basically tells whether the device is there. Are there software node
> > based devices, i.e. do you need this?
> >
> > If you do really need this, then I guess this could just return true for
> > now as if you somehow get here, the node is a software node anyway.
> 
> I do think its better to include it; I'm targeting using this with
> ipu3-cio2; the cio2_parse_firmware() call there doesn't pass
> FWNODE_GRAPH_DEVICE_DISABLED to fwnode_graph_get_endpoint_by_id() so

I wonder if this has something to do with replacing the device's fwnode
in the cio2-bridge patch.

It's the device that needs to be enabled, and it's not a software node.

-- 
Regards,

Sakari Ailus