linux-kernel - Re: [PATCH 4/4] spi: Document option to insert delay between transactions

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Date:	Thu, 30 Jun 2016 21:45:59 -0700
From:	Doug Anderson <dianders@...omium.org>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:	apronin@...omium.org, Mark Brown <broonie@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-spi <linux-spi@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH 4/4] spi: Document option to insert delay between transactions

Hi,

On Thu, Jun 30, 2016 at 12:12 AM, Geert Uytterhoeven
<geert@...ux-m68k.org> wrote:
> CC devicetree
>
> On Thu, Jun 30, 2016 at 5:54 AM,  <apronin@...omium.org> wrote:
>> From: Andrey Pronin <apronin@...omium.org>
>>
>> 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.
>>
>> Signed-off-by: Andrey Pronin <apronin@...omium.org>
>> ---
>>  Documentation/devicetree/bindings/spi/spi-bus.txt | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
>> index 1b7ffd4..87c117a 100644
>> --- a/Documentation/devicetree/bindings/spi/spi-bus.txt
>> +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
>> @@ -70,6 +70,8 @@ contain the following properties.
>>                 sleep if there was no SPI activity (msec).
>>  - cs-wake-duration - (optional) Time it takes the device to wake up after
>>                 toggling CS if it went to sleep (msec).
>> +- xfer-delay      - (optional) Delay to insert between SPI transactions
>> +               to guarantee that CS is deasserted at least for some time.

msec?  usec?  nsec?

Also, as with the other patch, this should be _before_ the code
change, so this should really be patch 3 not patch 4.