From: Daniel Mack <daniel@zonque.org>
To: Linus Walleij <linus.walleij@linaro.org>,
Haojian Zhuang <haojian.zhuang@gmail.com>,
Robert Jarzmik <robert.jarzmik@free.fr>
Cc: linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: dts: pxa3xx: Fix polarity on Raumfeld SPI CS
Date: Wed, 17 Jul 2019 23:05:10 +0200 [thread overview]
Message-ID: <a5eae78c-5ca7-b270-cd82-342b470dcfa7@zonque.org> (raw)
In-Reply-To: <20190716213520.31427-1-linus.walleij@linaro.org>
On 16/7/2019 11:35 PM, Linus Walleij wrote:
> The SPI CS is active low and you probably will get a
> warning in dmesg of the DT core enforcing it active low.
>
> The reason it was set as GPIO_ACTIVE_HIGH in the old
> board file was that the old spi-gpio driver would
> invert the value and drive it low deliberately to
> activate CS. The SPI and gpiolib core handling now
> expects proper polarity to be used in the machine
> descriptions.
Can't test this right now, but your explanation makes sense.
> Cc: Robert Jarzmik <robert.jarzmik@free.fr>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Daniel Mack <daniel@zonque.org>
Thanks,
Daniel
> ---
> arch/arm/boot/dts/pxa300-raumfeld-common.dtsi | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/boot/dts/pxa300-raumfeld-common.dtsi b/arch/arm/boot/dts/pxa300-raumfeld-common.dtsi
> index 8ac24e3c8513..86568637e6d9 100644
> --- a/arch/arm/boot/dts/pxa300-raumfeld-common.dtsi
> +++ b/arch/arm/boot/dts/pxa300-raumfeld-common.dtsi
> @@ -78,9 +78,9 @@
> gpio-miso = <&gpio 98 GPIO_ACTIVE_HIGH>;
> gpio-mosi = <&gpio 97 GPIO_ACTIVE_HIGH>;
> cs-gpios = <
> - &gpio 34 GPIO_ACTIVE_HIGH
> - &gpio 125 GPIO_ACTIVE_HIGH
> - &gpio 96 GPIO_ACTIVE_HIGH
> + &gpio 34 GPIO_ACTIVE_LOW
> + &gpio 125 GPIO_ACTIVE_LOW
> + &gpio 96 GPIO_ACTIVE_LOW
> >;
> num-chipselects = <3>;
>
>
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prev parent reply other threads:[~2019-07-17 21:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-16 21:35 [PATCH] ARM: dts: pxa3xx: Fix polarity on Raumfeld SPI CS Linus Walleij
2019-07-17 21:05 ` Daniel Mack [this message]
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