From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iA9gk-0007ja-Jr for barebox@lists.infradead.org; Tue, 17 Sep 2019 09:22:25 +0000 References: <20190906140127.17396-1-a.fatoum@pengutronix.de> <20190909072331.4xmc6nvjgfdxged3@pengutronix.de> From: Ahmad Fatoum Message-ID: <0f039d89-2b64-ae91-a0c3-30c10c461c34@pengutronix.de> Date: Tue, 17 Sep 2019 11:22:19 +0200 MIME-Version: 1.0 In-Reply-To: <20190909072331.4xmc6nvjgfdxged3@pengutronix.de> Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] gpio: add driver for SN74273 output expander To: Sascha Hauer Cc: barebox@lists.infradead.org On 9/9/19 9:23 AM, Sascha Hauer wrote: > On Fri, Sep 06, 2019 at 04:01:27PM +0200, Ahmad Fatoum wrote: >> The SN74273 is an octal D-Type Flip-Flop. When used as an output expander, >> N existing output signals can be turned into (N-8)*8 outputs using >> N-8 chips. Add driver to facilitate this. > > The reason I haven't mainlined this driver when writing it was that > Linux also has a driver for the 74273, but in a completely different > setup. In the Linux driver the 74273 is assumed to have its inputs on > the data bus together with a separate address decoder. > The chip in this driver here instead is connected via GPIO pins. For > Using flipflops as GPIO expanders there a myriads of different ways to > implement, so I have my doubts how useful it is to even try to put them > in a generic driver. FTR: I talked this over with Sascha. As I understood, the main issue is with reserving a fairly generic "ti,74273-gpio" compatible with what is a very special way of using these flip flops. We could however get it in with a different proprietary compatible. I might revisit this in future along with a kernel driver, but please dismiss for now. > > Sascha > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox