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From: Boris Brezillon <boris.brezillon@bootlin.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: "Janusz Krzysztofik" <jmkrzyszt@gmail.com>,
	"Miquèl Raynal" <miquel.raynal@bootlin.com>,
	"ext Tony Lindgren" <tony@atomide.com>,
	"Aaro Koskinen" <aaro.koskinen@iki.fi>,
	"Grygorii Strashko" <grygorii.strashko@ti.com>,
	"Santosh Shilimkar" <ssantosh@kernel.org>,
	"Kevin Hilman" <khilman@kernel.org>,
	"Richard Weinberger" <richard@nod.at>,
	"David Woodhouse" <dwmw2@infradead.org>,
	"Brian Norris" <computersforpeace@gmail.com>,
	"Mark Vasut" <marek.vasut@gmail.com>,
	linux-mtd@lists.infradead.org,
	"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
	Linux-OMAP <linux-omap@vger.kernel.org>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Artem Bityutskiy" <artem.bityutskiy@linux.intel.com>
Subject: Re: [RFC PATCH 7/8] mtd: rawnand: ams-delta: Check sanity of data GPIO resource
Date: Sun, 29 Jul 2018 23:16:19 +0200	[thread overview]
Message-ID: <20180729231422.0264f971@bbrezillon> (raw)
In-Reply-To: <CACRpkdZfiCN3U57s-7hGnbO9W-=pOjt0mL0w=Jv_+5WBdkEuig@mail.gmail.com>

On Sun, 29 Jul 2018 22:36:49 +0200
Linus Walleij <linus.walleij@linaro.org> wrote:

> On Thu, Jul 19, 2018 at 8:44 AM Boris Brezillon
> <boris.brezillon@bootlin.com> wrote:
> 
> > I guess you'd prefer to have the pin values in a bitmap instead of an
> > array of integers. That's probably something you can discuss with
> > Linus, see if he would accept to change the prototype of
> > gpiod_get_raw_array_value().  
> 
> I am not so smart as to see the overall effects but if what
> you're saying is that we shouldn't have designed these functions
> and callbacks using arrays of integers (or longs) and instead
> pass bitmaps, you may be just right. It intuitively sounds better.

Maybe, maybe not. Only an real evaluation of where the overhead is can
tell us. So I'd suggest trying to use the existing interface and doing
the int_array -> u8 conversion in the NAND driver first, and see how
much moving to a bitmap imprsoves things.

> But I'm not good with bitmaps.
> 
> We would have to refactor the world though.

I checked and, AFAICT, there are no external users of this API (only
core code is using those funcs, for ioctls I guess). Anyway, I think
we should wait for real numbers before we consider doing this change
(It's not unusual to get this sort of things wrong).

  reply	other threads:[~2018-07-29 21:16 UTC|newest]

Thread overview: 93+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-18 23:57 [RFC PATCH 0/8] mtd: rawnand: ams-delta: Use gpio-omap accessors for data I/O Janusz Krzysztofik
2018-07-18 23:57 ` [RFC PATCH 1/8] mtd: rawnand: ams-delta: Use private structure Janusz Krzysztofik
2018-07-19  6:17   ` Boris Brezillon
2018-07-20 17:57     ` Janusz Krzysztofik
2018-07-18 23:57 ` [RFC PATCH 2/8] mtd: rawnand: ams-delta: Write protect device during probe Janusz Krzysztofik
2018-07-19  6:22   ` Boris Brezillon
2018-07-20 18:02     ` Janusz Krzysztofik
2018-07-18 23:57 ` [RFC PATCH 3/8] mtd: rawnand: ams-delta: Set port direction once per transfer Janusz Krzysztofik
2018-07-19  6:23   ` Boris Brezillon
2018-07-20 18:12     ` Janusz Krzysztofik
2018-07-20 19:29       ` Boris Brezillon
2018-07-18 23:57 ` [RFC PATCH 4/8] mtd: rawnand: ams-delta: Optimize pointer resolution on read/write Janusz Krzysztofik
2018-07-19  6:25   ` Boris Brezillon
2018-07-20 18:14     ` Janusz Krzysztofik
2018-07-20 19:29       ` Boris Brezillon
2018-07-18 23:57 ` [RFC PATCH 5/8] mtd: rawnand: ams-delta: Request data port GPIO resource Janusz Krzysztofik
2018-07-19  6:28   ` Boris Brezillon
2018-07-18 23:57 ` [RFC PATCH 6/8] gpio: omap: Add get/set_multiple() callbacks Janusz Krzysztofik
2018-07-29 20:29   ` Linus Walleij
2018-08-03  1:52     ` Grygorii Strashko
2018-08-03 16:47   ` Linus Walleij
2018-07-18 23:57 ` [RFC PATCH 7/8] mtd: rawnand: ams-delta: Check sanity of data GPIO resource Janusz Krzysztofik
2018-07-19  6:44   ` Boris Brezillon
2018-07-29 20:36     ` Linus Walleij
2018-07-29 21:16       ` Boris Brezillon [this message]
2018-07-29 20:33   ` Linus Walleij
2018-07-18 23:57 ` [RFC PATCH 8/8] mtd: rawnand: ams-delta: Use GPIO callbacks for data I/O Janusz Krzysztofik
2018-07-19  6:47   ` Boris Brezillon
2018-07-20 18:38     ` Janusz Krzysztofik
2018-07-20 19:48       ` Boris Brezillon
2018-07-19  6:15 ` [RFC PATCH 0/8] mtd: rawnand: ams-delta: Use gpio-omap accessors " Boris Brezillon
2018-07-20 17:55   ` Janusz Krzysztofik
2018-07-20 19:25     ` Boris Brezillon
2018-08-06 22:29 ` [RFC PATCH v2] mtd: rawnand: ams-delta: Use GPIO API " Janusz Krzysztofik
2018-08-06 22:29   ` [RFC PATCH v2 01/12] mtd: rawnand: ams-delta: Assign mtd->dev.parent, not mtd->owner Janusz Krzysztofik
2018-08-06 23:54     ` Marek Vasut
2018-08-07 21:55       ` Janusz Krzysztofik
2018-08-07 16:57     ` Boris Brezillon
2018-08-06 22:29   ` [RFC PATCH v2 02/12] mtd: rawnand: ams-delta: Use private structure Janusz Krzysztofik
2018-08-07 16:59     ` Boris Brezillon
2018-08-06 22:29   ` [RFC PATCH v2 03/12] ARM: OMAP1: ams-delta: Provide GPIO lookup table for NAND data port Janusz Krzysztofik
2018-08-07 16:59     ` Boris Brezillon
2018-08-10 10:10     ` Linus Walleij
2018-08-06 22:29   ` [RFC PATCH v2 04/12] mtd: rawnand: ams-delta: request data port GPIO resource Janusz Krzysztofik
2018-08-07 17:00     ` Boris Brezillon
2018-08-10 10:11     ` Linus Walleij
2018-08-06 22:29   ` [RFC PATCH v2 05/12] mtd: rawnand: ams-delta: use GPIO API for data read/write Janusz Krzysztofik
2018-08-06 23:57     ` Marek Vasut
2018-08-07 17:06     ` Boris Brezillon
2018-08-07 17:11       ` Janusz Krzysztofik
2018-08-10 10:25     ` Linus Walleij
2018-08-06 22:29   ` [RFC PATCH v2 06/12] ARM: OMAP1: ams-delta: drop obsolete NAND resources Janusz Krzysztofik
2018-08-06 22:29   ` [RFC PATCH v2 07/12] mtd: rawnand: ams-delta: Set port direction once per transfer Janusz Krzysztofik
2018-08-07 18:57     ` Boris Brezillon
2018-08-08 16:55       ` Janusz Krzysztofik
2018-08-08 17:42         ` Miquel Raynal
2018-08-06 22:29   ` [RFC PATCH v2 08/12] mtd: rawnand: ams-delta: Simplify pointer resolution on read/write Janusz Krzysztofik
2018-08-07 17:02     ` Boris Brezillon
2018-08-07 17:15       ` Janusz Krzysztofik
2018-08-06 22:29   ` [RFC PATCH v2 09/12] gpiolib: Identify GPIO descriptor arrays with direct mapping Janusz Krzysztofik
2018-08-06 23:29     ` Linus Walleij
2018-08-07 16:50       ` Janusz Krzysztofik
2018-08-07 17:10         ` Boris Brezillon
2018-08-07 17:14     ` Boris Brezillon
2018-08-07 17:19       ` Janusz Krzysztofik
2018-08-06 22:29   ` [RFC PATCH v2 10/12] gpiolib: Introduce bitmap get/set array API extension Janusz Krzysztofik
2018-08-06 22:29   ` [RFC PATCH v2 11/12] mtd: rawnand: ams-delta: Use GPIO API bitmap extension Janusz Krzysztofik
2018-08-06 22:29   ` [RFC PATCH v2 12/12] gpiolib: Add fast processing path to bitmap API functions Janusz Krzysztofik
2018-08-06 23:43     ` Linus Walleij
2018-08-07 17:29       ` Janusz Krzysztofik
2018-08-07 17:47         ` Boris Brezillon
2018-08-10 10:55           ` Linus Walleij
2018-08-13 22:34   ` [PATCH v3 0/7] mtd: rawnand: ams-delta: Use GPIO API for data I/O Janusz Krzysztofik
2018-08-13 22:34     ` [PATCH v3 1/7] mtd: rawnand: ams-delta: show parent device in sysfs Janusz Krzysztofik
2018-08-13 22:34     ` [PATCH v3 2/7] mtd: rawnand: ams-delta: Use private structure Janusz Krzysztofik
2018-08-13 22:34     ` [PATCH v3 3/7] ARM: OMAP1: ams-delta: Provide GPIO lookup table for NAND data port Janusz Krzysztofik
2018-08-13 22:34     ` [PATCH v3 4/7] mtd: rawnand: ams-delta: request data port GPIO resource Janusz Krzysztofik
2018-08-13 22:34     ` [PATCH v3 5/7] mtd: rawnand: ams-delta: Set port direction when needed Janusz Krzysztofik
2018-08-16  7:30       ` Boris Brezillon
2018-08-13 22:34     ` [PATCH v3 6/7] mtd: rawnand: ams-delta: Simplify pointer resolution on read/write Janusz Krzysztofik
2018-08-13 22:34     ` [PATCH v3 7/7] mtd: rawnand: ams-delta: use GPIO API for data I/O Janusz Krzysztofik
2018-08-16  7:39       ` Boris Brezillon
2018-11-21 11:08     ` Subject: [PATCH v4 0/4] mtd: rawnand: ams-delta: Use " Janusz Krzysztofik
2018-11-21 11:08       ` [PATCH v4 1/4] ARM: OMAP1: ams-delta: Provide GPIO lookup table for NAND data port Janusz Krzysztofik
2018-11-23 17:02         ` Tony Lindgren
2018-11-21 11:08       ` [PATCH v4 2/4] mtd: rawnand: ams-delta: Request data port GPIO resource Janusz Krzysztofik
2018-11-21 11:08       ` [PATCH v4 3/4] mtd: rawnand: ams-delta: Use GPIO API for data I/O Janusz Krzysztofik
2018-11-21 14:53         ` Boris Brezillon
2018-11-21 11:08       ` [PATCH v4 4/4] ARM: OMAP1: ams-delta: Drop obsolete NAND resources Janusz Krzysztofik
2018-11-21 14:56       ` Subject: [PATCH v4 0/4] mtd: rawnand: ams-delta: Use GPIO API for data I/O Boris Brezillon
2018-11-23 17:03         ` Tony Lindgren
2018-12-07  8:04           ` Miquel Raynal
2018-12-07 16:10             ` Tony Lindgren

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