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From: Linus Walleij <linus.walleij@linaro.org>
To: arm@kernel.org, soc@kernel.org
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Mark Brown <broonie@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: dts: dir685: Drop spi-cpol from the display
Date: Sun, 15 Sep 2019 15:54:44 +0200
Message-ID: <20190915135444.11066-1-linus.walleij@linaro.org> (raw)

The D-Link DIR-685 had its clock polarity set as active
low using the special SPI "spi-cpol" property.

This is not correct: the datasheet clearly states:
"Fix SCL to GND level when not in use" which is
indicative that this line is active high.

After a recent fix making the GPIO-based SPI driver
force the clock line de-asserted at the beginning of
each SPI transaction this reared its ugly head: now
de-asserted was taken to mean the line should be
driven high, but it should be driven low.

Fix this up in the DTS file and the display works again.

Cc: Mark Brown <broonie@kernel.org>
Fixes: 2922d1cc1696 ("spi: gpio: Add SPI_MASTER_GPIO_SS flag")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ARM SoC folks: please apply this directly to fixes if
you're OK with the patch.
---
 arch/arm/boot/dts/gemini-dlink-dir-685.dts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm/boot/dts/gemini-dlink-dir-685.dts b/arch/arm/boot/dts/gemini-dlink-dir-685.dts
index bfaa2de63a10..e2030ba16512 100644
--- a/arch/arm/boot/dts/gemini-dlink-dir-685.dts
+++ b/arch/arm/boot/dts/gemini-dlink-dir-685.dts
@@ -72,7 +72,6 @@
 			reg = <0>;
 			/* 50 ns min period = 20 MHz */
 			spi-max-frequency = <20000000>;
-			spi-cpol; /* Clock active low */
 			vcc-supply = <&vdisp>;
 			iovcc-supply = <&vdisp>;
 			vci-supply = <&vdisp>;
-- 
2.21.0


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Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-15 13:54 Linus Walleij [this message]
2019-09-16 14:31 ` Arnd Bergmann

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