From: Boris Brezillon <bbrezillon@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
MTD Maling List <linux-mtd@lists.infradead.org>,
Nguyen An Hoan <na-hoan@jinso.co.jp>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-spi <linux-spi@vger.kernel.org>
Subject: Re: [PATCH v2 0/2] eeprom: at25: SPI transfer improvements
Date: Wed, 30 Jan 2019 15:55:43 +0100 [thread overview]
Message-ID: <20190130155543.5ab749b5@bbrezillon> (raw)
In-Reply-To: <CAMuHMdVfVHUQnjwvFikqQJ8HBD+0A7DSCTcdDN4e7V4c=4Usug@mail.gmail.com>
On Tue, 29 Jan 2019 20:02:37 +0100
Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> Hi Boris,
>
> On Fri, Jan 18, 2019 at 11:07 PM Boris Brezillon <bbrezillon@kernel.org> wrote:
> > Did you consider converting this driver to spimem? Looks like the
> > protocol used to communicate with the memory resembles the one used on
> > SPI NANDs/NORs and fits pretty well in the spi_mem_op representation.
> >
> > By doing this conversion you'd allow people to connect an AT25 EEPROM
> > to an advanced SPI controller that does not support regular SPI
> > transfers and you wouldn't have to forge SPI messages manually.
> >
> > Here is a patch (only compile tested) doing that. The diffstat is not in
> > favor of this conversion, but I find the resulting code cleaner and more
> > future proof.
>
> Thanks, seems to work fine, with the 512-byte 25LC040 I have!
>
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
>
> I did notice that the first two-byte transfer (command+offset) of each
> message is now split in two one-byte transfers, though.
That's something we can optimize in drivers/spi/spi-mem.c if you think
it makes a difference.
WARNING: multiple messages have this Message-ID (diff)
From: Boris Brezillon <bbrezillon@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-spi <linux-spi@vger.kernel.org>,
Nguyen An Hoan <na-hoan@jinso.co.jp>,
MTD Maling List <linux-mtd@lists.infradead.org>
Subject: Re: [PATCH v2 0/2] eeprom: at25: SPI transfer improvements
Date: Wed, 30 Jan 2019 15:55:43 +0100 [thread overview]
Message-ID: <20190130155543.5ab749b5@bbrezillon> (raw)
In-Reply-To: <CAMuHMdVfVHUQnjwvFikqQJ8HBD+0A7DSCTcdDN4e7V4c=4Usug@mail.gmail.com>
On Tue, 29 Jan 2019 20:02:37 +0100
Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> Hi Boris,
>
> On Fri, Jan 18, 2019 at 11:07 PM Boris Brezillon <bbrezillon@kernel.org> wrote:
> > Did you consider converting this driver to spimem? Looks like the
> > protocol used to communicate with the memory resembles the one used on
> > SPI NANDs/NORs and fits pretty well in the spi_mem_op representation.
> >
> > By doing this conversion you'd allow people to connect an AT25 EEPROM
> > to an advanced SPI controller that does not support regular SPI
> > transfers and you wouldn't have to forge SPI messages manually.
> >
> > Here is a patch (only compile tested) doing that. The diffstat is not in
> > favor of this conversion, but I find the resulting code cleaner and more
> > future proof.
>
> Thanks, seems to work fine, with the 512-byte 25LC040 I have!
>
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
>
> I did notice that the first two-byte transfer (command+offset) of each
> message is now split in two one-byte transfers, though.
That's something we can optimize in drivers/spi/spi-mem.c if you think
it makes a difference.
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http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2019-01-30 14:55 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-18 14:05 [PATCH v2 0/2] eeprom: at25: SPI transfer improvements Geert Uytterhoeven
2019-01-18 14:05 ` Geert Uytterhoeven
2019-01-18 14:05 ` [PATCH v2 1/2] eeprom: at25: Merge "off" and "offset" in at25_ee_write() Geert Uytterhoeven
2019-01-18 14:05 ` Geert Uytterhoeven
2019-01-26 10:06 ` Boris Brezillon
2019-01-26 10:06 ` Boris Brezillon
2019-01-18 14:05 ` [PATCH v2 2/2] eeprom: at25: Use spi_message_init_with_transfers() instead of open coding Geert Uytterhoeven
2019-01-18 14:05 ` Geert Uytterhoeven
2019-01-26 10:06 ` Boris Brezillon
2019-01-26 10:06 ` Boris Brezillon
2019-01-18 22:07 ` [PATCH v2 0/2] eeprom: at25: SPI transfer improvements Boris Brezillon
2019-01-18 22:07 ` Boris Brezillon
2019-01-23 18:10 ` Geert Uytterhoeven
2019-01-23 18:10 ` Geert Uytterhoeven
2019-01-29 19:02 ` Geert Uytterhoeven
2019-01-29 19:02 ` Geert Uytterhoeven
2019-01-30 14:50 ` Greg Kroah-Hartman
2019-01-30 14:50 ` Greg Kroah-Hartman
2019-01-30 15:08 ` Boris Brezillon
2019-01-30 15:08 ` Boris Brezillon
2019-01-30 19:40 ` Greg Kroah-Hartman
2019-01-30 19:40 ` Greg Kroah-Hartman
2019-01-30 14:55 ` Boris Brezillon [this message]
2019-01-30 14:55 ` Boris Brezillon
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