From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Date: Wed, 27 Apr 2016 12:40:37 -0600 Subject: [U-Boot] [RFC PATCH] dm: ensure device names are unique In-Reply-To: <571FDF66.8020607@wwwdotorg.org> References: <1461706228-3092-1-git-send-email-swarren@wwwdotorg.org> <571FDF66.8020607@wwwdotorg.org> Message-ID: <572107A5.40807@wwwdotorg.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 04/26/2016 03:36 PM, Stephen Warren wrote: > On 04/26/2016 03:30 PM, Stephen Warren wrote: >> From: Stephen Warren >> >> It is possible for HW to contain multiple instances of the same >> device. In >> this case, the name passed to device_bind() may not be unique across all >> devices within its uclass. One example is a system with multiple >> identical >> PCI Ethernet devices. Another might be a system with multiple identical >> I2C GPIO expanders, each connected to a separate I2C bus, yet using the >> same I2C address on that bus and hence having the same DT node name. >> >> Enhance the code to detect this situation, and append a sequence >> number so >> the device name to ensure uniqueness. >> >> Signed-off-by: Stephen Warren >> --- >> Some possible issues with this patch: >> >> 1) Doing this in bind() rather than probe() means dev->seq isn't >> available, so can't be used to generate the unique name. This process >> should be done during bind() rather than probe() though, since devices >> can >> be seen (e.g. by running "dm tree") before they're probed. Perhaps the >> uclass_resolve_seq() should be called by bind() not probe(). >> >> 2) uclass_find_device_by_name() needs to look up the uclass pointer again >> even though device_bind() already knows it. >> >> 3) Iterating over the list to find the count of devices in the uclass >> is a >> bit annoying. Should the uclass maintain this count so it doesn't need to >> be re-calculated each time? > > 4) This causes "ut dm autobind" to fail. I'll investigate that locally, > but won't bother reposting until the questions above are considered. It looks like that's because I need to add "gd->dm_root && " to the start of the following condition: > @@ -62,6 +62,23 @@ int device_bind(struct udevice *parent, const struct driver *drv, > dev->driver = drv; > dev->uclass = uc; > > + if (!uclass_find_device_by_name(uc->uc_drv->id, dev->name, &dev2)) { ... otherwise, the uc_class_get/find() nested inside that end up creating a second root uclass. I can fold that into v2, pending any other comments.