Re: [PATCH 3/4] spi: Add option to insert delay between transactions

From	Mark Brown <broonie@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/4] spi: Add option to insert delay between transactions
Date	2016-07-01 11:10 +0200
Message-ID	<rQ2Cu-4KR-9@gated-at.bofh.it> (permalink)
References	<rPBiV-4y7-3@gated-at.bofh.it> <rPBiV-4y7-1@gated-at.bofh.it>
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On Wed, Jun 29, 2016 at 08:54:26PM -0700, apronin@chromium.org wrote:

> Some devices may need CS to be deasserted for some time
> between transactions. Added a new capability to guarantee
> a delay between SPI transactions for the device.

This seems like even more of a per device thing - it's a very rare
requirement (I'm guessing for some SPI controller coprocessor) and
there's such a wide range of potential patterns that might be needed
by different devices.  

> +       if (msg->spi->xfer_delay)
> +               mdelay(msg->spi->xfer_delay);
> +
>         spi_set_cs(msg->spi, true);

This isn't a delay between messages, it's a delay before asserting
chip select which will happen every single time we do anything
regardless of if there was any activity immediately before or not.

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[PATCH 3/4] spi: Add option to insert delay between transactions apronin@chromium.org - 2016-06-30 06:00 +0200
  Re: [PATCH 3/4] spi: Add option to insert delay between transactions Doug Anderson <dianders@chromium.org> - 2016-07-01 06:50 +0200
  Re: [PATCH 3/4] spi: Add option to insert delay between transactions Mark Brown <broonie@kernel.org> - 2016-07-01 11:10 +0200

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