Re: [PATCH v3 13/13] platform/x86: intel_cht_int33fe: Replacing the old connections with references

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Wed, Apr 17, 2019 at 06:03:03PM +0200, Hans de Goede wrote:
> Hi,
> 
> On 17-04-19 12:44, Heikki Krogerus wrote:
> > On Wed, Apr 17, 2019 at 12:15:18PM +0200, Hans de Goede wrote:
> > > Hi,
> > > 
> > > On 17-04-19 11:32, Heikki Krogerus wrote:
> > > > On Wed, Apr 17, 2019 at 11:19:28AM +0200, Hans de Goede wrote:
> > > 
> > > <snip>
> > > 
> > > > > That is not going to work since the (virtual) mux / orientation-switch
> > > > > devices are only registered once the driver binds to the piusb30532 i2c
> > > > > device, so when creating the nodes we only have the piusb30532 i2c device.
> > > > 
> > > > It's not a problem, that's why we have the software nodes. The nodes
> > > > can be created before the device entires. The node for pi3usb30532
> > > > will just be the parent node for the new nodes we add for the mux and
> > > > switch.
> > > > 
> > > > > I've been thinking some more about this and an easy fix is to have separate
> > > > > fwnode_match functions for typec_switch_match and typec_mux_match and have
> > > > > them check that the dev_name ends in "-mux" resp. "-switch" that requires
> > > > > only a very minimal change to "usb: typec: Registering real device entries for the muxes"
> > > > > and then everything should be fine.
> > > > 
> > > > I don't want to do anymore device name matching unless we have to, and
> > > > here we don't have to. We can name the nodes for those virtual mux and
> > > > switch, and then just do fwnode_find_named_child_node() in
> > > > pi3usb30532.c for both of them.
> > > 
> > > Thinking more about this, I have a feeling that this makes things needlessly
> > > complicated, checking the dev_name *ends* in "-mux" resp. "-switch" should be
> > > 100% reliable since we call:
> > > 
> > >          dev_set_name(&sw->dev, "%s-switch", dev_name(parent));
> > >          dev_set_name(&mux->dev, "%s-mux", dev_name(parent));
> > > 
> > > When registering the switch / mux, so I believe doing name (suffix) comparison
> > > here is fine and much simpler. Anyways this is just my 2 cents on this, I'm
> > > happy with either solution, your choice.
> > 
> > You do have a point. I'll take a look how the two options look like,
> > but maybe your way is better after all.
> 
> I whipped up a quick fix using my approach so that I can start working
> on debugging the usb_role_switch_get call in tcpm.c returning NULL.
> 
> I've attached it, feel free to use this for v4 of the series if you
> decide to go with this approach.

Thanks. I'll probable use that as is.


> >From 47154195c05dc7c8b3373de9603b06c2f435588a Mon Sep 17 00:00:00 2001
> From: Hans de Goede <hdegoede@redhat.com>
> Date: Wed, 17 Apr 2019 17:58:17 +0200
> Subject: [PATCH v2] FIXUP: "usb: typec: Registering real device entries for
>  the muxes"
> 
> Check the dev_name suffix so that we do not return the first registered
> device when a mux and switch share the same parent and fwnode.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/usb/typec/mux.c | 25 +++++++++++++++++++++----
>  1 file changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/typec/mux.c b/drivers/usb/typec/mux.c
> index c7d4a2dd454e..a28803544301 100644
> --- a/drivers/usb/typec/mux.c
> +++ b/drivers/usb/typec/mux.c
> @@ -22,9 +22,21 @@ static int name_match(struct device *dev, const void *name)
>  	return !strcmp((const char *)name, dev_name(dev));
>  }
>  
> -static int fwnode_match(struct device *dev, const void *fwnode)
> +static bool dev_name_ends_with(struct device *dev, const char *suffix)
>  {
> -	return dev_fwnode(dev) == fwnode;
> +	const char *name = dev_name(dev);
> +	const int name_len = strlen(name);
> +	const int suffix_len = strlen(suffix);
> +
> +	if (suffix_len > name_len)
> +		return false;
> +
> +	return strcmp(name + (name_len - suffix_len), suffix) == 0;
> +}
> +
> +static int switch_fwnode_match(struct device *dev, const void *fwnode)
> +{
> +	return dev_fwnode(dev) == fwnode && dev_name_ends_with(dev, "-switch");
>  }
>  
>  static void *typec_switch_match(struct device_connection *con, int ep,
> @@ -37,7 +49,7 @@ static void *typec_switch_match(struct device_connection *con, int ep,
>  			return NULL;
>  
>  		dev = class_find_device(&typec_mux_class, NULL, con->fwnode,
> -					fwnode_match);
> +					switch_fwnode_match);
>  	} else {
>  		dev = class_find_device(&typec_mux_class, NULL,
>  					con->endpoint[ep], name_match);
> @@ -167,6 +179,11 @@ EXPORT_SYMBOL_GPL(typec_switch_get_drvdata);
>  
>  /* ------------------------------------------------------------------------- */
>  
> +static int mux_fwnode_match(struct device *dev, const void *fwnode)
> +{
> +	return dev_fwnode(dev) == fwnode && dev_name_ends_with(dev, "-mux");
> +}
> +
>  static void *typec_mux_match(struct device_connection *con, int ep, void *data)
>  {
>  	const struct typec_altmode_desc *desc = data;
> @@ -226,7 +243,7 @@ static void *typec_mux_match(struct device_connection *con, int ep, void *data)
>  
>  find_mux:
>  	dev = class_find_device(&typec_mux_class, NULL, con->fwnode,
> -				fwnode_match);
> +				mux_fwnode_match);
>  
>  	return dev ? to_typec_switch(dev) : ERR_PTR(-EPROBE_DEFER);
>  }
> -- 
> 2.21.0
> 

cheers,

-- 
heikki