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From: Trent Piepho <tpiepho-cgc2CodaaHDQT0dZR+AlfA@public.gmane.org>
To: "kyle.roeschley-acOepvfBmUk@public.gmane.org"
	<kyle.roeschley-acOepvfBmUk@public.gmane.org>,
	"geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org"
	<geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org>
Cc: "linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org"
	<broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: spidev: Instantiating from DT as "spidev"
Date: Thu, 30 Nov 2017 02:07:37 +0000	[thread overview]
Message-ID: <1512007657.9792.45.camel@impinj.com> (raw)
In-Reply-To: <CAMuHMdX62=vC6=P-v=SPe_hq0F12tOZCgePaS7=MZZg_4PkvUw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Wed, 2017-11-29 at 23:18 +0100, Geert Uytterhoeven wrote:
> 
> To me, the above sounds a bit contradictive: either you have
>   1. a simple (trivial) description, which can be handled by spidev and
>      userspace, and thus by just writing "<unit-addr> spidev" to a new_device
>      sysfs node, or
>   2. a complex description, for which you need a specialized in-kernel driver,
>      so you're gonna need a real DT node (and overlays?) to describe it.
> 
> I don't think writing a complex description to a new_device sysfs node makes
> sense.

Is there anything one can do with new_device that can't be done with a
dt fragment?

I2C added that feature a long time ago, when we were still largely
using platform_data and board files and device tree fragments didn't
exist.  It seems obsolete to me.  Maybe easier to use if you limit
yourself to what's in busybox, but I think one could write a simple
shell script that makes it just as simple to create new devices with dt
fragments as with new_device.

  parent reply	other threads:[~2017-11-30  2:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-29 15:04 spidev: Instantiating from DT as "spidev" Kyle Roeschley
2017-11-29 16:32 ` Geert Uytterhoeven
     [not found]   ` <CAMuHMdUps9Ti=CRZM7UxrHLD8GA+FKD+_RFLW3H9wUpSRTYs8w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-11-29 19:24     ` Kyle Roeschley
2017-11-29 22:18       ` Geert Uytterhoeven
     [not found]         ` <CAMuHMdX62=vC6=P-v=SPe_hq0F12tOZCgePaS7=MZZg_4PkvUw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-11-30  2:07           ` Trent Piepho [this message]
     [not found]             ` <1512007657.9792.45.camel-cgc2CodaaHDQT0dZR+AlfA@public.gmane.org>
2017-11-30  8:03               ` Geert Uytterhoeven
     [not found]                 ` <CAMuHMdXv2WsGCUBD4Td9K1zOfZ9DOfeW5rYtCyq27Ucp21xGRA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-11-30 22:24                   ` Kyle Roeschley
2017-12-12 18:44                     ` Kyle Roeschley
2017-11-29 20:22     ` Trent Piepho

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