linux-api.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Arnd Bergmann <arnd@arndb.de>
To: Lyra Zhang <zhang.lyra@gmail.com>
Cc: "Murali Karicheri" <m-karicheri2@ti.com>,
	"Chunyan Zhang" <chunyan.zhang@spreadtrum.com>,
	"Grant Likely" <grant.likely@linaro.org>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"ijc+devicetree@hellion.org.uk" <ijc+devicetree@hellion.org.uk>,
	"jslaby@suse.cz" <jslaby@suse.cz>,
	"Kumar Gala" <galak@codeaurora.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Pawel Moll" <pawel.moll@arm.com>,
	"Ramkumar Ramachandra" <artagnon@gmail.com>,
	"rrichter@cavium.com" <rrichter@cavium.com>,
	"Will Deacon" <will.deacon@arm.com>,
	"gnomes@lxorguk.ukuu.org.uk" <gnomes@lxorguk.ukuu.org.uk>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"jason@lakedaemon.net" <jason@lakedaemon.net>,
	"Mark Brown" <broonie@kernel.org>,
	"Heiko Stübner" <heiko@sntech.de>,
	"florian.vaussard@epfl.ch" <florian.vaussard@epfl.ch>
Subject: Re: [PATCH v3 5/5] tty/serial: Add Spreadtrum sc9836-uart driver support
Date: Thu, 27 Nov 2014 16:36:52 +0100	[thread overview]
Message-ID: <7773522.25QE5ibXJZ@wuerfel> (raw)
In-Reply-To: <CAAfSe-uWvn4MX-+GKuvvd=G2MTfLDCFeLRoUGWp7vvc81wfu0w@mail.gmail.com>

On Thursday 27 November 2014 23:23:17 Lyra Zhang wrote:
> 
> Yes, I saw this way in other serial drivers.
> But, if then, there are two questions for me:
> 1. Why did some serial drivers need an UN_SHARED irq?

A lot of drivers were written before we had shared IRQs, or
were copied from old drivers, or are for hardware that uses
edge-triggered interrupts instead of level-triggered interrupts.

Only level-triggered interrupts can be shared.

> 2. How can we choose a right way?

It never hurts to implement a shared interrupt handler. Only
if you have no way to find out whether the device triggered
the interrupt or not you have to leave out IRQF_SHARED, and then
you won't be able to return IRQ_NONE.

	Arnd

  parent reply	other threads:[~2014-11-27 15:36 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Sharkl64-v3>
2014-11-25 12:16 ` [PATCH v3 0/5] Add Spreadtrum Sharkl64 Platform support Chunyan Zhang
2014-11-25 12:16   ` [PATCH v3 1/5] Documentation: DT: Renamed of-serial.txt to 8250.txt Chunyan Zhang
     [not found]     ` <1416917818-10506-2-git-send-email-chunyan.zhang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org>
2014-11-27 11:38       ` Mark Rutland
2014-11-27 12:08         ` Lyra Zhang
2014-11-25 12:16   ` [PATCH v3 2/5] Documentation: DT: Add bindings for Spreadtrum SoC Platform Chunyan Zhang
2014-11-25 12:52     ` Arnd Bergmann
2014-11-25 12:16   ` [PATCH v3 3/5] arm64: dts: Add support for Spreadtrum SC9836 SoC in dts and Makefile Chunyan Zhang
2014-11-27 11:50     ` Mark Rutland
2014-11-27 12:12       ` Catalin Marinas
2014-11-27 13:43         ` Mark Rutland
2014-11-28 14:29           ` Catalin Marinas
2014-11-28 14:35             ` Mark Rutland
2014-11-28 14:44               ` Will Deacon
2014-11-28 14:46                 ` Mark Rutland
2014-11-28 14:59                   ` Will Deacon
2014-11-28 14:50                 ` Mark Brown
     [not found]                 ` <20141128144412.GG7144-5wv7dgnIgG8@public.gmane.org>
2014-11-28 15:03                   ` Catalin Marinas
2014-11-28 15:09                     ` Will Deacon
2014-11-28 16:40                     ` Mark Rutland
2014-11-28 17:24                       ` Catalin Marinas
2014-12-03  9:16       ` Lyra Zhang
2014-11-25 12:16   ` [PATCH v3 4/5] arm64: Add support for Spreadtrum's Sharkl64 Platform in Kconfig and defconfig Chunyan Zhang
2014-11-25 12:57     ` Arnd Bergmann
2014-11-26  3:08       ` Lyra Zhang
     [not found]       ` <CAAfSe-uoXOJ8=agCFuBnXhj7nBBTskQ=8_jMtv_SAjor2gfO2w@mail.gmail.com>
     [not found]         ` <CAAfSe-uoXOJ8=agCFuBnXhj7nBBTskQ=8_jMtv_SAjor2gfO2w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-11-26  9:00           ` Arnd Bergmann
2014-11-25 12:16   ` [PATCH v3 5/5] tty/serial: Add Spreadtrum sc9836-uart driver support Chunyan Zhang
2014-11-25 20:03     ` Greg KH
2014-11-27 11:05       ` Lyra Zhang
2014-11-26  9:48     ` Tobias Klauser
2014-11-27 11:39       ` Lyra Zhang
2014-11-26 12:33     ` One Thousand Gnomes
2014-11-28 10:13       ` Orson Zhai
2014-11-26 18:29     ` Murali Karicheri
2014-11-27 11:59       ` Lyra Zhang
     [not found]         ` <CAAfSe-uMqy7zwiEK+nDoMPw_oni8L_vq7oW2Me5AY8z8KGpjwQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-11-27 12:57           ` Arnd Bergmann
2014-11-27 15:23             ` Lyra Zhang
2014-11-27 15:34               ` One Thousand Gnomes
2014-11-27 15:36               ` Arnd Bergmann [this message]
2014-12-03  9:17       ` Lyra Zhang
     [not found]         ` <CAAfSe-u+g0mYGi9Adrd+YwwZ=q0-s79yCg_paB1UAVqFoufXEA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-12-03  9:50           ` Arnd Bergmann
2014-12-03 10:11             ` Russell King - ARM Linux
     [not found]               ` <20141203101109.GB11285-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2014-12-03 12:08                 ` Lyra Zhang
2014-12-03 12:15             ` Lyra Zhang
2014-11-25 12:57   ` [PATCH v3 0/5] Add Spreadtrum Sharkl64 Platform support Mark Brown
2014-11-25 12:59   ` Arnd Bergmann
2014-11-27 12:03   ` Mark Rutland

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=7773522.25QE5ibXJZ@wuerfel \
    --to=arnd@arndb.de \
    --cc=artagnon@gmail.com \
    --cc=broonie@kernel.org \
    --cc=catalin.marinas@arm.com \
    --cc=chunyan.zhang@spreadtrum.com \
    --cc=corbet@lwn.net \
    --cc=florian.vaussard@epfl.ch \
    --cc=galak@codeaurora.org \
    --cc=gnomes@lxorguk.ukuu.org.uk \
    --cc=grant.likely@linaro.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=heiko@sntech.de \
    --cc=ijc+devicetree@hellion.org.uk \
    --cc=jason@lakedaemon.net \
    --cc=jslaby@suse.cz \
    --cc=m-karicheri2@ti.com \
    --cc=mark.rutland@arm.com \
    --cc=pawel.moll@arm.com \
    --cc=robh+dt@kernel.org \
    --cc=rrichter@cavium.com \
    --cc=will.deacon@arm.com \
    --cc=zhang.lyra@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).