On Thu, Jul 21, 2016 at 10:41:28AM +0100, Russell King - ARM Linux wrote: > On Thu, Jul 21, 2016 at 05:20:12PM +0800, Peter Chen wrote: > > On Thu, Jul 21, 2016 at 10:14:38AM +0100, Russell King - ARM Linux wrote: > > > On Wed, Jul 20, 2016 at 05:40:28PM +0800, Peter Chen wrote: > > > > diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c > > > > index 69426e6..0d05812 100644 > > > > --- a/drivers/usb/chipidea/core.c > > > > +++ b/drivers/usb/chipidea/core.c > > > > @@ -914,6 +914,16 @@ static int ci_hdrc_probe(struct platform_device *pdev) > > > > if (!ci) > > > > return -ENOMEM; > > > > > > > > + /* > > > > + * At device tree, we have no device node for chipidea core, > > > > + * the glue layer's node is the parent node for host and udc > > > > + * device. But in related driver, the parent device is chipidea > > > > + * core. So, in order to let the common driver get parent's node, > > > > + * we let the core's device node equals glue layer's node. > > > > + */ > > > > + if (dev->parent && dev->parent->of_node) > > > > + dev->of_node = dev->parent->of_node; > > > > > > This is a dangerous thing to do. You're changing the dev->of_node of > > > _this_ device, which means that _this_ driver will no longer match > > > the device if you remove and reinsert the driver module, or unbind > > > and try to re-bind the device to this driver. > > > > > > > Thanks for commenting it. > > > > I have tested load/unload, it does not show any problems. > > > > The chipidea core device is created by code at runtime, not by device node. > > And we have NO device node for this chipidea core device at dts. > > Okay, so we still probably have the bind/unbind problem, where "dev" > can be matched by the driver which claimed "dev->parent". Remember, > in an OF environment, driver matching is done by the compatible > property, which is accessed via dev->of_node. > > Therefore, I would suggest that you NULL dev->of_node in the error > cleanup paths and in the remove function, so you don't have an > unbound device with a duplicated (but inappropriate) dev->of_node > pointer. > Although it does no mismatch between driver and device due to the driver has no of_match_table, I find it has below re-request pinctrl error after re-bind, that's due to the parent device which has of_node and there is a pinctrl property in it. imx6sx-pinctrl 20e0000.iomuxc: pin MX6SX_PAD_GPIO1_IO10 already requested by 2184000.usb; cannot claim for ci_hdrc.0 After adding your suggestion, this error has gone, thanks. -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
