Re: [PATCH 5/6] leds: pca963x: Inform the output that it is inverted

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Hey Rob,

On 21-04-16 17:07, Rob Herring wrote:
On Tue, Apr 19, 2016 at 09:40:49AM +0200, Olliver Schinagl wrote:
When leds are connected in a totem-pole configuration, they can be
connected either in a active-high, or active-low manor. The driver
currently always assumes active-high. This patch adds the
'nxp,inverted-out' boolean property to tell the driver that the leds
are driven active-low, or rather, that the behavior is inverted to what
is normally expected.
How do I know what is normally expected?
fair point, and in fact, you don't. The text is bad here.

Signed-off-by: Olliver Schinagl <oliver@xxxxxxxxxxx>
---
  Documentation/devicetree/bindings/leds/pca963x.txt |  1 +
  drivers/leds/leds-pca963x.c                        | 20 +++++++++++++-------
  include/linux/platform_data/leds-pca963x.h         |  1 +
  3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/Documentation/devicetree/bindings/leds/pca963x.txt b/Documentation/devicetree/bindings/leds/pca963x.txt
index dafbe99..7b23725 100644
--- a/Documentation/devicetree/bindings/leds/pca963x.txt
+++ b/Documentation/devicetree/bindings/leds/pca963x.txt
@@ -6,6 +6,7 @@ Required properties:
  Optional properties:
  - nxp,totem-pole : use totem pole (push-pull) instead of open-drain (pca9632 defaults
    to open-drain, newer chips to totem pole)
+  nxp,inverted-out: the connected leds are active-low, default to active-high
Just state what mode you want: nxp,active-low
But that's not what happens, which is why my text is bad :) It depends on how the board is wired and if it is push-pull or open-drain. Though this goes beyond my electronics knowledge. So I'll reduce the text to say exactly what we mean, inverted output (or not).

Unless you can explain that it would be unrelated and it is actually active-high/low. I'll be more than happy to oblige.

Olliver

Rob

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