Re: [PATCH 16/16] arm64: dts: marvell: armada-3720-espressobin: fill UART nodes

From: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
To: Miquel Raynal
	<miquel.raynal-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
Cc: Greg Kroah-Hartman
	<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
	Linus Walleij
	<linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>,
	Andrew Lunn <andrew-g2DYL2Zd6BY@public.gmane.org>,
	Sebastian Hesselbarth
	<sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Jiri Slaby <jslaby-IBi9RG/b67k@public.gmane.org>,
	Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>,
	Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>,
	linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Thomas Petazzoni
	<thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>,
	Antoine Tenart
	<antoine.tenart-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>,
	Nadav Haklai <nadavh-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>,
	Wilson Ding <dingwei-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>
Subject: Re: [PATCH 16/16] arm64: dts: marvell: armada-3720-espressobin: fill UART nodes
Date: Fri, 06 Oct 2017 15:01:18 +0200	[thread overview]
Message-ID: <87fuawe8gx.fsf@free-electrons.com> (raw)
In-Reply-To: <20171006101344.15590-17-miquel.raynal-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> (Miquel Raynal's message of "Fri, 6 Oct 2017 12:13:44 +0200")

Hi Miquel,

 On ven., oct. 06 2017, Miquel Raynal <miquel.raynal-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> wrote:

> Fill ESPRESSObin uart0 node with pinctrl information like in the
> Armada-3720-DB device tree (which uses the same node).
>
> Also explain how to enable the second UART port available on the
> headers. This second port is not enabled by default because both
> headers are dedicated to expose general purpose pins and remapping
> some of them to use the second UART would break existing users.
>
> Suggested-by: László ÁSHIN <laszlo-3b5oun+KfQA@public.gmane.org>
> Signed-off-by: Miquel Raynal <miquel.raynal-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> ---
>  arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts b/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts
> index 2ce52ba74f73..c05b274ab1a9 100644
> --- a/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts
> +++ b/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts
> @@ -98,9 +98,17 @@
>  
>  /* Exported on the micro USB connector J5 through an FTDI */
>  &uart0 {
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&uart1_pins>;
>  	status = "okay";
>  };
>  
> +/*
> + * Enabling the second UART on J17 (pins 24,26) is just a matter of copying the
> + * uart1 node from armada-3720-db.dts with one difference: it works with 1.8V
> + * TTL levels.

This difference is not related to the device tree. So I would write:
 /*
  * To enable the second UART on J17 (pins 24,26) refer to the uart1
  * node from armada-3720-db.dts.
  * Note that TX and RX signal are the ones coming directly from the SoC:
  * 1.8V TTL.
  */

Thanks,

Gregory

> + */
> +
>  /* J7 */
>  &usb3 {
>  	status = "okay";
> -- 
> 2.11.0
>

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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