From: Simon Glass <sjg@chromium.org>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 1/2] SPI: Add support for preamble bytes
Date: Sat, 11 May 2013 08:42:16 -0600 [thread overview]
Message-ID: <CAPnjgZ06DM7_uyEQgpOv9xzb_RZzz7B=U+khnmHzwf3U0h69Sg@mail.gmail.com> (raw)
In-Reply-To: <1363933766-6555-2-git-send-email-rajeshwari.s@samsung.com>
On Fri, Mar 22, 2013 at 12:29 AM, Rajeshwari Shinde
<rajeshwari.s@samsung.com> wrote:
> A SPI slave may take time to react to a request. For SPI flash devices
> this time is defined as one bit time, or a whole byte for 'fast read'
> mode.
>
> If the SPI slave is another CPU, then the time it takes to react may
> vary. It is convenient to allow the slave device to tag the start of
> the actual reply so that the host can determine when this 'preamble'
> finishes and the actual message starts.
>
> Add a preamble flag to the available SPI flags. If supported by the
> driver then it will ignore any received bytes before the preamble
> on each transaction. This ensures that reliable communication with
> the slave is possible.
>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
next prev parent reply other threads:[~2013-05-11 14:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-22 6:29 [U-Boot] [PATCH 0/2] SPI: Enable SPI_PREAMBLE Mode Rajeshwari Shinde
2013-03-22 6:29 ` [U-Boot] [PATCH 1/2] SPI: Add support for preamble bytes Rajeshwari Shinde
2013-05-11 14:42 ` Simon Glass [this message]
2013-03-22 6:29 ` [U-Boot] [PATCH 2/2] EXYNOS: SPI: Support SPI_PREAMBLE mode Rajeshwari Shinde
2013-05-03 1:28 ` Vadim Bendebury
2013-05-06 12:06 ` Simon Glass
2013-05-11 14:41 ` Simon Glass
2013-05-11 15:04 ` [U-Boot] [PATCH v2] " Simon Glass
2013-05-11 15:05 ` Simon Glass
2013-05-21 12:30 ` Minkyu Kang
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