From: Linus Walleij <linus.walleij@linaro.org>
To: arm@kernel.org
Cc: Linus Walleij <linus.walleij@linaro.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: dts: nomadik: Fix polarity of SPI CS
Date: Mon, 18 Mar 2019 16:31:22 +0100 [thread overview]
Message-ID: <20190318153122.10257-1-linus.walleij@linaro.org> (raw)
The SPI DT bindings are for historical reasons a pitfall,
the ability to flag a GPIO line as active high/low with
the second cell flags was introduced later so the SPI
subsystem will only accept the bool flag spi-cs-high
to indicate that the line is active high.
It worked by mistake, but the mistake was corrected
in another commit.
The comment in the DTS file was also misleading: this
CS is indeed active high.
Fixes: cffbb02dafa3 ("ARM: dts: nomadik: Augment NHK15 panel setting")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ARM SoC people: please apply this directly for fixes
if you're OK with it.
---
arch/arm/boot/dts/ste-nomadik-nhk15.dts | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/arm/boot/dts/ste-nomadik-nhk15.dts b/arch/arm/boot/dts/ste-nomadik-nhk15.dts
index 04066f9cb8a3..f2f6558a00f1 100644
--- a/arch/arm/boot/dts/ste-nomadik-nhk15.dts
+++ b/arch/arm/boot/dts/ste-nomadik-nhk15.dts
@@ -213,12 +213,13 @@
gpio-sck = <&gpio0 5 GPIO_ACTIVE_HIGH>;
gpio-mosi = <&gpio0 4 GPIO_ACTIVE_HIGH>;
/*
- * It's not actually active high, but the frameworks assume
- * the polarity of the passed-in GPIO is "normal" (active
- * high) then actively drives the line low to select the
- * chip.
+ * This chipselect is active high. Just setting the flags
+ * to GPIO_ACTIVE_HIGH is not enough for the SPI DT bindings,
+ * it will be ignored, only the special "spi-cs-high" flag
+ * really counts.
*/
cs-gpios = <&gpio0 6 GPIO_ACTIVE_HIGH>;
+ spi-cs-high;
num-chipselects = <1>;
/*
--
2.20.1
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next reply other threads:[~2019-03-18 15:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 15:31 Linus Walleij [this message]
2019-03-25 16:03 ` [PATCH] ARM: dts: nomadik: Fix polarity of SPI CS Arnd Bergmann
2019-04-07 10:16 ` Linus Walleij
2019-04-07 22:19 ` Olof Johansson
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