Re: [PATCH] Make EN2 pin optional in the TRF7970A driver

From: Heiko Schocher
Date: Mon Feb 13 2017 - 01:38:41 EST

Hello Rob,

Am 10.02.2017 um 16:51 schrieb Rob Herring:
On Tue, Feb 07, 2017 at 06:22:04AM +0100, Heiko Schocher wrote:
From: Guan Ben <ben.guan@xxxxxxxxxxxx>

Make the EN2 pin optional. This is useful for boards,
which have this pin fix wired, for example to ground.

Signed-off-by: Guan Ben <ben.guan@xxxxxxxxxxxx>
Signed-off-by: Mark Jonas <mark.jonas@xxxxxxxxxxxx>
Signed-off-by: Heiko Schocher <hs@xxxxxxx>


.../devicetree/bindings/net/nfc/trf7970a.txt | 4 ++--
drivers/nfc/trf7970a.c | 26 ++++++++++++----------
2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
index 32b35a0..5889a3d 100644
--- a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
+++ b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
@@ -5,8 +5,8 @@ Required properties:
- spi-max-frequency: Maximum SPI frequency (<= 2000000).
- interrupt-parent: phandle of parent interrupt handler.
- interrupts: A single interrupt specifier.
-- ti,enable-gpios: Two GPIO entries used for 'EN' and 'EN2' pins on the
- TRF7970A.
+- ti,enable-gpios: One or two GPIO entries used for 'EN' and 'EN2' pins on the
+ TRF7970A. EN2 is optional.

Could EN ever be optional/fixed? If so, perhaps deprecate this property
and do 2 properties, one for each pin.

The hardware I have has the EN2 pin fix connected to ground. Looking
into page 19 table 6-3
and 6-4 the EN2 pin is a don;t core if EN = 1. If EN = 0 EN2 pin
selects between Power Down and Sleep Mode ... I see no reason why
this is not possible/allowed ...

Hmm.. I do not like the idea of deprecating the "ti,enable-gpios"
property into 2 seperate properties ... but if this would be a reason
for not accepting this patch, I can do this ... How should I name
the 2 new properties?

"ti,pin-enable" and "ti,pin-enable2" ?

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