From: eric@eukrea.com (Eric Bénard)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 5/8] gpio: 74x164: Add output pin support
Date: Wed, 5 Sep 2012 11:46:45 +0200 [thread overview]
Message-ID: <20120905114645.57bfe591@eb-e6520> (raw)
In-Reply-To: <20120905112012.13ce2c86@skate>
Hi Thomas,
Le Wed, 5 Sep 2012 11:20:12 +0200,
Thomas Petazzoni <thomas.petazzoni@free-electrons.com> a ?crit :
> Le Wed, 5 Sep 2012 10:40:54 +0200,
> Maxime Ripard <maxime.ripard@free-electrons.com> a ?crit :
>
> > The shift registers have an output that, when enabled, propagates the
> > values of its internal register to the pins. Make use of this pin
> > through the output-latch-gpio dt property.
> >
> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>
> Well, thinking more about this, and reviewing the i.MX 28 datasheet a
> bit more thoroughly, I don't think you need this GPIO thing. It is an
> active-low pin that should be kept low during the entire duration of
> the transfer, which basically is a chip select. And in turns out that
> the CFA10049 board uses pins that can be controlled as chip selects
> directly by the SPI controller, so you should rather use this rather
> than introduce a specially handled GPIO. This needs testing, but I
> don't see why it wouldn't work.
>
are you talking of the /OE pin of the 74HC595 ?
Eric
next prev parent reply other threads:[~2012-09-05 9:46 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-05 8:40 [PATCH 1/8] gpio: 74x164: Use module_spi_driver boiler plate function Maxime Ripard
2012-09-05 8:40 ` [PATCH 2/8] gpio: 74x164: Use devm_kzalloc Maxime Ripard
2012-09-05 8:46 ` Florian Fainelli
2012-09-05 9:16 ` Thomas Petazzoni
2012-09-06 7:22 ` Linus Walleij
2012-09-07 21:02 ` Linus Walleij
2012-09-05 8:40 ` [PATCH 3/8] gpio: 74x164: Remove platform data and use dynamic gpio number assignment Maxime Ripard
2012-09-05 8:48 ` Florian Fainelli
2012-09-05 9:15 ` Thomas Petazzoni
2012-09-05 9:17 ` Thomas Petazzoni
2012-09-05 8:40 ` [PATCH 4/8] gpio: 74x164: Add device tree support Maxime Ripard
2012-09-05 8:50 ` Florian Fainelli
2012-09-05 9:17 ` Thomas Petazzoni
2012-09-06 7:22 ` Linus Walleij
2012-09-05 8:40 ` [PATCH 5/8] gpio: 74x164: Add output pin support Maxime Ripard
2012-09-05 9:20 ` Thomas Petazzoni
2012-09-05 9:46 ` Eric Bénard [this message]
2012-09-05 10:09 ` Thomas Petazzoni
2012-09-05 10:26 ` Eric Bénard
2012-09-05 11:56 ` Thomas Petazzoni
2012-09-05 12:22 ` Eric Bénard
2012-09-05 12:29 ` Thomas Petazzoni
2012-09-05 12:54 ` Eric Bénard
2012-09-05 13:02 ` Maxime Ripard
2012-09-05 13:27 ` Eric Bénard
2012-09-05 8:40 ` [PATCH 6/8] gpio: 74x164: Add support for daisy-chaining Maxime Ripard
2012-09-05 8:56 ` Thomas Petazzoni
2012-09-05 8:40 ` [PATCH 7/8] gpio: 74x164: dts: Add documentation for the dt binding Maxime Ripard
2012-09-05 8:40 ` [PATCH 8/8] ARM: dts: cfa10049: Add the 74HC595 gpio expanders Maxime Ripard
2012-09-05 8:46 ` [PATCH 1/8] gpio: 74x164: Use module_spi_driver boiler plate function Florian Fainelli
2012-09-05 9:16 ` Thomas Petazzoni
2012-09-06 7:21 ` Linus Walleij
2012-09-06 14:10 ` Maxime Ripard
2012-09-07 21:09 ` Linus Walleij
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