From: Greg KH <gregkh@linuxfoundation.org>
To: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Linux-Kernel <linux-kernel@vger.kernel.org>,
devicetree@vger.kernel.org,
shimoda <yoshihiro.shimoda.uh@renesas.com>,
goda <yusuke.goda.sx@renesas.com>,
Kurokawa <harunobu.kurokawa.dn@renesas.com>,
Kihara <takeshi.kihara.df@renesas.com>,
kazuya.mizuguchi.ks@renesas.com, takamitsu.honda.pv@renesas.com
Subject: Re: Question about UIO vs DT
Date: Thu, 15 May 2025 09:52:29 +0200 [thread overview]
Message-ID: <2025051549-flannels-lively-a46d@gregkh> (raw)
In-Reply-To: <87o6vutrbw.wl-kuninori.morimoto.gx@renesas.com>
On Thu, May 15, 2025 at 04:45:23AM +0000, Kuninori Morimoto wrote:
>
> Hi Greg / UIO / DT
>
> I would like to ask about UIO vs DT.
>
> If my understanding was correct, current UIO can use 1 IRQ / 1 reg per 1 UIO,
> but some device needs multi-IRQ/reg. In such case, we need to use
> multi-UIO. But it is not good much to DT rule. For example in case of
> the device which needs "2 regs 3 irqs". it will be
>
> (A) [1 reg, 1 IRQ] UIO
> (B) [1 reg, 1 IRQ] UIO
> (C) [0 reg, 1 IRQ] UIO
>
> and (C) will be DT error. Is this known issue ? Do we have better solution ?
Yes, write a real driver for the device as obviously it is a complex one
and UIO shouldn't be used for it :)
What type of device is this that requires this type of hardware control
and why do you feel that UIO is the proper solution?
thanks,
greg k-h
next prev parent reply other threads:[~2025-05-15 7:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-15 4:45 Question about UIO vs DT Kuninori Morimoto
2025-05-15 7:52 ` Greg KH [this message]
2025-05-16 2:18 ` Kuninori Morimoto
2025-05-16 6:03 ` Greg KH
2025-05-16 7:05 ` Kuninori Morimoto
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