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From: Peter Rosin <peda@axentia.se>
To: Ingo van Lil <inguin@gmx.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Ludovic Desroches <ludovic.desroches@microchip.com>
Subject: Re: [PATCH] ARM: dts: at91: Reenable UART TX pull-ups
Date: Tue, 3 Dec 2019 13:04:56 +0000	[thread overview]
Message-ID: <8e8dfc02-bdab-d6f1-f6e9-e1dba7e38bfd@axentia.se> (raw)
In-Reply-To: <20191128100629.10247-1-inguin@gmx.de>

On 2019-11-28 11:06, Ingo van Lil wrote:
> Pull-ups for SAM9 UART/USART TX lines were disabled in 5e04822f.
> However, several chips in the SAM9 family require pull-ups to prevent
> the TX lines from falling (and causing an endless break condition) when
> the transceiver is disabled.
> 
> From the SAM9G20 datasheet, 32.5.1: "To prevent the TXD line from
> falling when the USART is disabled, the use of an internal pull up
> is mandatory.". This commit reenables the pull-ups for all chips having
> that sentence in their datasheets.
> 
> Signed-off-by: Ingo van Lil <inguin@gmx.de>

Sounds reasonable, and sorry for the breakage. However, perhaps a proper
fixes tag (with the prescribed length of the commit hash) should be in
there somewhere?

Fixes: 5e04822f7db5 ("ARM: dts: at91: fixes uart pinctrl, set pullup on rx, clear pullup on tx")

Also, I think the same kind of change was made to the barebox bootloader
at about the same time. Is there a fix for that queued up as well?

Cheers,
Peter
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  reply	other threads:[~2019-12-03 13:05 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-28 10:06 [PATCH] ARM: dts: at91: Reenable UART TX pull-ups Ingo van Lil
2019-12-03 13:04 ` Peter Rosin [this message]
2019-12-03 13:22   ` Ingo van Lil
2019-12-03 14:21 Ingo van Lil
2019-12-10 10:57 ` Alexandre Belloni

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