Re: [RFC PATCH 06/10] usb: xhci: Add Tegra XHCI host-controller driver

From: Thierry Reding
Date: Thu May 15 2014 - 05:21:54 EST


On Thu, May 15, 2014 at 10:17:10AM +0200, Arnd Bergmann wrote:
> On Wednesday 14 May 2014 17:33:02 Andrew Bresticker wrote:
[...]
> > + /* Create child xhci-plat device */
> > + memset(xhci_resources, 0, sizeof(xhci_resources));
> > + res = platform_get_resource(to_platform_device(dev), IORESOURCE_IRQ, 0);
> > + if (!res) {
> > + dev_err(dev, "Missing XHCI IRQ\n");
> > + ret = -ENODEV;
> > + goto out;
> > + }
> > + xhci_resources[0].start = res->start;
> > + xhci_resources[0].end = res->end;
> > + xhci_resources[0].flags = res->flags;
> > + xhci_resources[0].name = res->name;
> > + res = platform_get_resource(to_platform_device(dev), IORESOURCE_MEM, 0);
> > + if (!res) {
> > + dev_err(dev, "Missing XHCI registers\n");
> > + ret = -ENODEV;
> > + goto out;
> > + }
> > + xhci_resources[1].start = res->start;
> > + xhci_resources[1].end = res->end;
> > + xhci_resources[1].flags = res->flags;
> > + xhci_resources[1].name = res->name;
> > +
> > + xhci = platform_device_alloc("xhci-hcd", PLATFORM_DEVID_AUTO);
> > + if (!xhci) {
> > + dev_err(dev, "Failed to allocate XHCI host\n");
> > + ret = -ENOMEM;
> > + goto out;
> > + }
>
> This does not feel appropriate at all: Rather than creating a child device,
> you should have a specific driver that hooks into functions exported
> by the xhci core. See Documentation/driver-model/design-patterns.txt

I don't think Documentation/driver-model/design-patterns.txt documents
this. Perhaps this is what you had in mind?

http://lwn.net/Articles/336262/

Thierry

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