From: Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
To: Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>
Cc: tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org,
computersforpeace-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
nsekhar-l0cyMroinI0@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
ezequiel-30ULvvUtt6G51wMPkGsGjgyUoB5FGQPZ@public.gmane.org,
javier-0uQlZySMnqxg9hUCZPvPmw@public.gmane.org,
linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org,
fcooper-l0cyMroinI0@public.gmane.org
Subject: Re: [PATCH v5 13/26] memory: omap-gpmc: Support general purpose input for WAITPINs
Date: Mon, 7 Mar 2016 11:31:00 +0100 [thread overview]
Message-ID: <20160307113100.2fb12bf4@bbrezillon> (raw)
In-Reply-To: <56DD519A.3070403-l0cyMroinI0@public.gmane.org>
On Mon, 7 Mar 2016 12:02:02 +0200
Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org> wrote:
> Hi Boris,
>
> On 07/03/16 11:34, Boris Brezillon wrote:
> > Hi Roger,
> >
> > On Fri, 19 Feb 2016 23:15:35 +0200
> > Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org> wrote:
> >
> >> OMAPs can have 2 to 4 WAITPINs that can be used as general purpose
> >> input if not used for memory wait state insertion.
> >>
> >> The first user will be the OMAP NAND chip to get the NAND
> >> read/busy status using gpiolib.
> >
> > Just a comment on this approach. Why do you need to exposed native R/B
> > pins as GPIOs? I mean, other NAND controllers are supporting R/B
> > detection using dedicated logic, and they do not exposed those pins a
> > plain GPIOs. Have you considered adding another property (rb-native ?)
> > to deal with this case instead of emulating a GPIO controller?
> > Side note: I added an rb-gpios property in my sunxi-nand DT binding
> > because in some cases, the board design forces us to use a plain GPIO.
>
> OMAPs can have more than one WAITpins which can be used in multiple ways
> - wait state insertion
> - general purpose input
> - edge detect interrupt
>
> It is not automatically tied to NAND read/busy# mechanism and needs software
> to get the read/busy# state.
> The register to get WAIT pin status is not situated in the NAND controller
> register space but in the parent GPMC controller space.
>
> So we've modelled the WAIT pins as irqchip and gpiochip and users can
> use them as they want.
Okay. Thanks for the detailed explanation.
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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next prev parent reply other threads:[~2016-03-07 10:31 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-19 21:15 [PATCH v5 00/26] memory: omap-gpmc: mtd: nand: Support GPMC NAND on non-OMAP platforms Roger Quadros
2016-02-19 21:15 ` [PATCH v5 01/26] ARM: OMAP2+: gpmc: Add platform data Roger Quadros
2016-02-19 21:15 ` [PATCH v5 02/26] ARM: OMAP2+: gpmc: Add gpmc timings and settings to " Roger Quadros
2016-02-19 21:15 ` [PATCH v5 03/26] memory: omap-gpmc: Introduce GPMC to NAND interface Roger Quadros
2016-03-05 1:35 ` Brian Norris
[not found] ` <20160305013534.GJ55664-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2016-03-07 8:55 ` Roger Quadros
2016-02-19 21:15 ` [PATCH v5 04/26] mtd: nand: omap2: Use gpmc_omap_get_nand_ops() to get NAND registers Roger Quadros
2016-02-19 21:15 ` [PATCH v5 05/26] memory: omap-gpmc: Add GPMC-NAND ops to get writebufferempty status Roger Quadros
2016-02-19 21:15 ` [PATCH v5 06/26] mtd: nand: omap2: Switch to using GPMC-NAND ops for writebuffer empty check Roger Quadros
2016-02-19 21:15 ` [PATCH v5 07/26] memory: omap-gpmc: Implement IRQ domain for NAND IRQs Roger Quadros
2016-02-19 21:15 ` [PATCH v5 08/26] mtd: nand: omap: Copy platform data parameters to omap_nand_info data Roger Quadros
2016-02-19 21:15 ` [PATCH v5 09/26] mtd: nand: omap: Clean up device tree support Roger Quadros
2016-03-05 2:10 ` Brian Norris
[not found] ` <20160305021035.GM55664-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2016-03-07 9:06 ` Roger Quadros
[not found] ` <1455916548-3441-10-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-03-05 2:28 ` Brian Norris
[not found] ` <20160305022823.GO55664-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2016-03-07 9:02 ` Roger Quadros
2016-02-19 21:15 ` [PATCH v5 10/26] mtd: nand: omap: Update DT binding documentation Roger Quadros
2016-02-23 19:41 ` Rob Herring
2016-02-24 9:55 ` Roger Quadros
[not found] ` <1455916548-3441-11-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-03-05 2:04 ` Brian Norris
2016-03-07 9:46 ` Roger Quadros
[not found] ` <56DD4DF0.4020500-l0cyMroinI0@public.gmane.org>
2016-03-07 18:58 ` Brian Norris
2016-03-07 10:32 ` [PATCH v6 " Roger Quadros
[not found] ` <56DD58AF.4090404-l0cyMroinI0@public.gmane.org>
2016-03-17 14:48 ` Rob Herring
2016-02-19 21:15 ` [PATCH v5 11/26] memory: omap-gpmc: Prevent mapping into 1st 16MB Roger Quadros
2016-02-19 21:15 ` [PATCH v5 12/26] memory: omap-gpmc: Move device tree binding to correct location Roger Quadros
2016-02-23 20:50 ` Rob Herring
2016-02-24 9:51 ` Roger Quadros
2016-02-19 21:15 ` [PATCH v5 13/26] memory: omap-gpmc: Support general purpose input for WAITPINs Roger Quadros
2016-03-07 9:34 ` Boris Brezillon
2016-03-07 9:38 ` Boris Brezillon
2016-03-07 10:02 ` Roger Quadros
[not found] ` <56DD519A.3070403-l0cyMroinI0@public.gmane.org>
2016-03-07 10:31 ` Boris Brezillon [this message]
2016-02-19 21:15 ` [PATCH v5 14/26] memory: omap-gpmc: Reserve WAITPIN if needed for WAIT monitoring Roger Quadros
2016-02-19 21:15 ` [PATCH v5 15/26] memory: omap-gpmc: Support WAIT pin edge interrupts Roger Quadros
2016-02-19 21:15 ` [PATCH v5 16/26] memory: omap-gpmc: Prevent GPMC_STATUS from being accessed via gpmc_regs Roger Quadros
2016-02-19 21:15 ` [PATCH v5 17/26] mtd: nand: omap2: Implement NAND ready using gpiolib Roger Quadros
[not found] ` <1455916548-3441-18-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-03-05 1:46 ` Brian Norris
[not found] ` <20160305014624.GK55664-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2016-03-07 9:11 ` Roger Quadros
2016-03-07 9:22 ` Boris Brezillon
2016-02-19 21:15 ` [PATCH v5 18/26] ARM: dts: dra7: Fix NAND device nodes Roger Quadros
2016-02-19 21:15 ` [PATCH v5 19/26] ARM: dts: dra7x-evm: Provide NAND ready pin Roger Quadros
2016-02-19 21:15 ` [PATCH v5 20/26] ARM: dts: am437x: Fix NAND device nodes Roger Quadros
2016-02-19 21:15 ` [PATCH v5 21/26] ARM: dts: am437x: Provide NAND ready pin Roger Quadros
2016-02-19 21:15 ` [PATCH v5 22/26] ARM: dts: am335x: Fix NAND device nodes Roger Quadros
2016-02-19 21:15 ` [PATCH v5 23/26] ARM: dts: am335x: Provide NAND ready pin Roger Quadros
2016-02-19 21:15 ` [PATCH v5 24/26] ARM: dts: dm814x: Fix gpmc and NAND node Roger Quadros
2016-02-19 21:15 ` [PATCH v5 25/26] ARM: dts: dm816x: " Roger Quadros
2016-02-19 21:15 ` [PATCH v5 26/26] ARM: dts: omap3: Fix gpmc and NAND nodes Roger Quadros
2016-02-19 22:04 ` [PATCH v5 00/26] memory: omap-gpmc: mtd: nand: Support GPMC NAND on non-OMAP platforms Tony Lindgren
[not found] ` <20160219220442.GR21202-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
2016-02-22 10:15 ` Roger Quadros
2016-02-22 16:42 ` Tony Lindgren
2016-02-22 20:05 ` Roger Quadros
2016-02-22 20:12 ` nick
[not found] ` <1455916548-3441-1-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-02-29 16:25 ` Roger Quadros
[not found] ` <56D470E8.4070106-l0cyMroinI0@public.gmane.org>
2016-03-05 2:33 ` Brian Norris
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