Messages in this thread | | | From | Vitor Soares <> | Subject | RE: [RFC 5/5] i3c: add i3cdev module to expose i3c dev in /dev | Date | Thu, 12 Dec 2019 17:25:28 +0000 |
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From: Greg KH <gregkh@linuxfoundation.org> Date: Thu, Dec 12, 2019 at 16:00:45
> On Thu, Dec 12, 2019 at 02:56:56PM +0000, Vitor Soares wrote: > > Hi Greg, > > > > From: Greg KH <gregkh@linuxfoundation.org> > > Date: Thu, Dec 12, 2019 at 14:44:59 > > > > > On Tue, Dec 10, 2019 at 04:37:33PM +0100, Vitor Soares wrote: > > > > +static int __init i3cdev_init(void) > > > > +{ > > > > + int res; > > > > + > > > > + pr_info("i3c /dev entries driver\n"); > > > > > > Please remove debugging information, kernel code should be quiet unless > > > something goes wrong. > > > > I will remove it. > > > > > > > > > + /* Dynamically request unused major number */ > > > > + res = alloc_chrdev_region(&i3cdev_number, 0, N_I3C_MINORS, "i3c"); > > > > > > Do you really need a whole major, or will a few minors work? > > > > > > thanks, > > > > > > greg k-h > > > > I'm reserving one per device. What do you suggest? > > How many devices do you have in a system?
According to MIPI I3C spec, the maximum number of devices on a bus will depend on trace length, bus load, and clock requirements.
Frankly, I don't know what is the best compromise because it depends from system to system and the end-use of it. In my case, I started developing this to help me during the HC controller driver development. Even If I choose a fixed major, I wouldn't know in which one i3c fits.
Best regards, Vitor Soares
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