[PATCH 2/4] spi: Document option to wake a device by toggling CS

From	apronin@chromium.org
Newsgroups	linux.kernel
Subject	[PATCH 2/4] spi: Document option to wake a device by toggling CS
Date	2016-06-30 06:00 +0200
Message-ID	<rPBiV-4y7-5@gated-at.bofh.it> (permalink)
References	<rPBiV-4y7-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Andrey Pronin <apronin@chromium.org>

Some SPI devices may go to sleep after a period of inactivity
on SPI. For such devices, if enough time has passed since the
last SPI transaction, toggle CS and wait for the device to
start before communicating with it.

Signed-off-by: Andrey Pronin <apronin@chromium.org>
---
 Documentation/devicetree/bindings/spi/spi-bus.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
index 42d5954..1b7ffd4 100644
--- a/Documentation/devicetree/bindings/spi/spi-bus.txt
+++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
@@ -63,6 +63,13 @@ contain the following properties.
                       used for MISO. Defaults to 1 if not present.
 - spi-rx-delay-us  - (optional) Microsecond delay after a read transfer.
 - spi-tx-delay-us  - (optional) Microsecond delay after a write transfer.
+- cs-wake-after-sleep - (optional) Device may go to sleep after a period
+		of SPI inactivity. If this flag is set, toggle CS and
+		wait for it to wake before communicating to it.
+- cs-sleep-delay  - (optional) Delay after which the device may go to
+		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).
 
 Some SPI controllers and devices support Dual and Quad SPI transfer mode.
 It allows data in the SPI system to be transferred in 2 wires(DUAL) or 4 wires(QUAD).
-- 
2.6.6

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[PATCH 2/4] spi: Document option to wake a device by toggling CS apronin@chromium.org - 2016-06-30 06:00 +0200
  Re: [PATCH 2/4] spi: Document option to wake a device by toggling CS Geert Uytterhoeven <geert@linux-m68k.org> - 2016-06-30 09:20 +0200
    Re: [PATCH 2/4] spi: Document option to wake a device by toggling CS Doug Anderson <dianders@chromium.org> - 2016-07-01 06:40 +0200

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