Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932634AbcJGTeE (ORCPT ); Fri, 7 Oct 2016 15:34:04 -0400 Received: from mail-it0-f68.google.com ([209.85.214.68]:36289 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753873AbcJGTd4 (ORCPT ); Fri, 7 Oct 2016 15:33:56 -0400 MIME-Version: 1.0 In-Reply-To: <1475852194-27690-1-git-send-email-tthayer@opensource.altera.com> References: <1475852194-27690-1-git-send-email-tthayer@opensource.altera.com> From: Geert Uytterhoeven Date: Fri, 7 Oct 2016 21:33:15 +0200 X-Google-Sender-Auth: E1et_Kbv7-Clkmqi-nyjvOehtro Message-ID: Subject: Re: [PATCHv2 1/2] Documentation: dt: spi: Add GPIO Slave Select Parameter To: tthayer@opensource.altera.com Cc: Mark Brown , Andy Shevchenko , Jarkko Nikula , jszhang@marvell.com, michael@smart-africa.com, kernel@mseidel.net, linux-spi , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1680 Lines: 42 On Fri, Oct 7, 2016 at 4:56 PM, wrote: > From: Thor Thayer > > Some SPI masters require the slave to be selected before a > transaction can occur - even in the case of GPIO chip select. > > This patch adds a GPIO slave select parameter to indicate > the slave needs to be selected in the GPIO CS case. > > Signed-off-by: Thor Thayer > --- > v2 Add to SPI framework - add bindings. > --- > Documentation/devicetree/bindings/spi/spi-bus.txt | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt > index 4b1d6e7..3a006bc 100644 > --- a/Documentation/devicetree/bindings/spi/spi-bus.txt > +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt > @@ -24,6 +24,7 @@ support describing the chip select layout. > Optional properties: > - cs-gpios - gpios chip select. > - num-cs - total number of chipselects. > +- gpio-ss - use internal slave select with gpio chip select. > > If cs-gpios is used the number of chip selects will be increased automatically > with max(cs-gpios > hw cs). To me, this looks more like a new flag the SPI controller driver should set in spi_master.flags, instead of a DT property. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds