From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: Re: [PATCH] gpio: serial: max310x: Support open-drain configuration for GPIOs Date: Tue, 9 Jan 2018 16:37:21 +0100 Message-ID: <20180109153721.GA17957@kroah.com> References: <18c9e927d2b75b3325ee3eae7e78319129faa779.1513983040.git.jan.kundrat@cesnet.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:51650 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933098AbeAIPhU (ORCPT ); Tue, 9 Jan 2018 10:37:20 -0500 Content-Disposition: inline In-Reply-To: <18c9e927d2b75b3325ee3eae7e78319129faa779.1513983040.git.jan.kundrat@cesnet.cz> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Jan =?iso-8859-1?Q?Kundr=E1t?= Cc: linux-gpio@vger.kernel.org, linux-serial@vger.kernel.org, Alexander Shiyan , Linus Walleij On Fri, Dec 22, 2017 at 09:29:44PM +0100, Jan Kundrát wrote: > The push-pull vs. open-drain are the only supported output modes. The > inputs are always unconditionally equipped with weak pull-downs. That's > the only mode, so there's probably no point in exporting that. I wonder > if it's worthwhile to provide a custom dbg_show method to indicate the > current status of the outputs, though. > > This patch and [1] for i2c-gpio together make it possible to bit-bang an > I2C bus over GPIOs of an UART which is connected via SPI :). Yes, this > is crazy, but it's fast enough (while on a 26Mhz SPI HW bus with a > dual-core 1.6GHz CPU) to drive an I2C bus at 200kHz, according to my > scope. > > [1] https://patchwork.ozlabs.org/patch/852591/ > > Signed-off-by: Jan Kundrát > Reviewed-by: Linus Walleij > --- > My suggestion is for this patch to go in via the tty/serial tree; I plan > to send more patches to this driver (and some of them are alreay in > tty-next). --jkt Doesn't apply to my tty-next branch, so I can't apply it, please rebase and resend. thanks, greg k-h