Date: Fri, 5 Jun 2020 00:01:22 +0530 From: Rajesh Kumar <rajfbsd@gmail.com> To: Warner Losh <imp@bsdimp.com> Cc: Andriy Gapon <avg@freebsd.org>, freebsd-drivers@freebsd.org, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: Can we hook a device as device to two different parent devices? Message-ID: <CAAO%2BANOQfY3AUy5o9BP22O5Uxp83crAXNhFrOeMcmsStkk4Y-w@mail.gmail.com> In-Reply-To: <CANCZdfpF%2BaiZYLRHo-NOizZcAuBz%2BXhsqYvXTazHrMVz_%2Bh=3w@mail.gmail.com> References: <CAAO%2BANOB8m6OjRY-FOVVHQi3vdcCEnHdjE2s3xoHdh0rjaTruQ@mail.gmail.com> <c1b611bc-4fa7-7975-da3f-e7c68a26e92b@FreeBSD.org> <CANCZdfpF%2BaiZYLRHo-NOizZcAuBz%2BXhsqYvXTazHrMVz_%2Bh=3w@mail.gmail.com>
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Thanks Warner and Andriy for your answers. Having said they are two separate instances, if the child driver calls the interface of two parents as below device1_interface(child_dev), then device_get_parent(child_dev) in the device1 interface will return device1 reference device2_interface(child_dev), then device_get_parent(child_dev) in the device2 interface will return device2 reference Is that right? Thanks, Rajesh. On Wed, Jun 3, 2020 at 8:59 PM Warner Losh <imp@bsdimp.com> wrote: > > > On Wed, Jun 3, 2020, 8:29 AM Andriy Gapon <avg@freebsd.org> wrote: > >> On 03/06/2020 14:20, Rajesh Kumar wrote: >> > Hi, >> > >> > Is it really possible to declare a module with two parents? Like the >> > following declarations in the same driver. >> > >> > devclass_t test_dev_devclass; >> > static DEFINE_CLASS_0(test_dev, test_dev_driver, test_dev_methods, >> > sizeof(struct test_dev_ctx)); >> > DRIVER_MODULE(test_dev, *device1*, test_dev_driver, test_dev_devclass, >> > NULL, NULL); >> > DRIVER_MODULE(test_dev, *device2*, test_dev_driver, test_dev_devclass, >> > NULL, NULL); >> > >> > I see similar references in other drivers attaching to both simpleus and >> > ofwbus. So, If it's possible, how to get the reference for both the >> > parents? device_get_parent(test_dev) will give reference of one parent >> > only right, so how to get the reference of the desired parent? >> >> A device can have only one parent. >> The declaration you quoted describes a _driver_ that can attach to devices >> hanging off two different buses. They would still be different devices. >> > > Yes. You can have a driver attach to multiple bus types, but each instance > has a unique parent one exactly on of them. > > If you need to talk to other devices, you'll need to find them by name or > other means. > > Warner > > > >> -- >> Andriy Gapon >> _______________________________________________ >> freebsd-drivers@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/freebsd-drivers >> To unsubscribe, send any mail to "freebsd-drivers-unsubscribe@freebsd.org >> " >> >
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