Linux LED subsystem development
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From: Andrew Jeffery <andrew@aj.id.au>
To: linux-leds@vger.kernel.org
Cc: Andrew Jeffery <andrew@aj.id.au>,
	rpurdie@rpsys.net, jacek.anaszewski@gmail.com, pavel@ucw.cz,
	robh+dt@kernel.org, mark.rutland@arm.com,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	joel@jms.id.au, openbmc@lists.ozlabs.org
Subject: [PATCH 1/2] dt-bindings: leds: gpio: Add optional retain-state-shutdown property
Date: Fri, 25 Aug 2017 16:05:02 +0930	[thread overview]
Message-ID: <20170825063503.31577-2-andrew@aj.id.au> (raw)
In-Reply-To: <20170825063503.31577-1-andrew@aj.id.au>

On BMC systems it's sometimes necessary for a LED to retain its state
across a BMC reset (which is independent of the host system state). Add
a devicetree property to describe this behaviour. The property would
typically be used in conjunction with 'default-state = "keep"'.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 Documentation/devicetree/bindings/leds/leds-gpio.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/leds-gpio.txt b/Documentation/devicetree/bindings/leds/leds-gpio.txt
index 76535ca37120..a48dda268f81 100644
--- a/Documentation/devicetree/bindings/leds/leds-gpio.txt
+++ b/Documentation/devicetree/bindings/leds/leds-gpio.txt
@@ -18,6 +18,9 @@ LED sub-node properties:
   see Documentation/devicetree/bindings/leds/common.txt
 - retain-state-suspended: (optional) The suspend state can be retained.Such
   as charge-led gpio.
+- retain-state-shutdown: (optional) Retain the state of the LED on shutdown.
+  Useful in BMC systems, for example when the BMC is rebooted while the host
+  remains up.
 - panic-indicator : (optional)
   see Documentation/devicetree/bindings/leds/common.txt
 
-- 
2.11.0

  reply	other threads:[~2017-08-25  6:35 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-25  6:35 [PATCH 0/2] leds: gpio: Allow retaining state on shutdown Andrew Jeffery
2017-08-25  6:35 ` Andrew Jeffery [this message]
2017-08-25  6:35 ` [PATCH 2/2] leds: gpio: Allow LED to retain state at shutdown Andrew Jeffery
2017-08-25  7:32   ` Pavel Machek
2017-08-27 11:01     ` Jacek Anaszewski
     [not found]       ` <3b89ad70-7024-b4ac-bf4e-49a02d12da51-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-08-28  0:00         ` Andrew Jeffery

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