Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751539AbdLZXXf (ORCPT ); Tue, 26 Dec 2017 18:23:35 -0500 Received: from mail-pf0-f196.google.com ([209.85.192.196]:40159 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751225AbdLZXXd (ORCPT ); Tue, 26 Dec 2017 18:23:33 -0500 X-Google-Smtp-Source: ACJfBovl1o2x2PTyWdDzz6GoFpAdjMKp3tIVd1zkSETgCdnHPtdiLP2bpyfV2wMNNcPb+zm8WpyhGw== Date: Tue, 26 Dec 2017 17:23:30 -0600 From: Rob Herring To: Cyrille Pitchen Cc: computersforpeace@gmail.com, dwmw2@infradead.org, richard@nod.at, boris.brezillon@free-electrons.com, marek.vasut@gmail.com, linux-mtd@lists.infradead.org, broonie@kernel.org, vigneshr@ti.com, linux@armlinux.org.uk, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, devicetree@vger.kernel.org, nicolas.ferre@microchip.com, radu.pirea@microchip.com Subject: Re: [PATCH 2/3] dt-bindings: mtd: atmel-quadspi: add an optional property 'dmacap,memcpy' Message-ID: <20171226232330.trljk2ofyvu4ly3n@rob-hp-laptop> References: <143542c61ca674d53da4985bbabc142e8e6ebefc.1514087323.git.cyrille.pitchen@wedev4u.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <143542c61ca674d53da4985bbabc142e8e6ebefc.1514087323.git.cyrille.pitchen@wedev4u.fr> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1897 Lines: 52 On Sun, Dec 24, 2017 at 05:36:05AM +0100, Cyrille Pitchen wrote: > The optional 'dmacap,memcpy' DT property tells the Atmel QSPI controller > driver to reserve some DMA channel then to use it to perform DMA > memcpy() during data transfers. This feature relies on the generic > bounce buffer helper from spi-nor.c. > > Signed-off-by: Cyrille Pitchen > --- > Documentation/devicetree/bindings/mtd/atmel-quadspi.txt | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mtd/atmel-quadspi.txt b/Documentation/devicetree/bindings/mtd/atmel-quadspi.txt > index b93c1e2f25dd..002d3f0a445b 100644 > --- a/Documentation/devicetree/bindings/mtd/atmel-quadspi.txt > +++ b/Documentation/devicetree/bindings/mtd/atmel-quadspi.txt > @@ -12,6 +12,10 @@ Required properties: > - #address-cells: Should be <1>. > - #size-cells: Should be <0>. > > +Optional properties: > +- dmacap,memcpy: Reserve a DMA channel to perform DMA memcpy() between the > + system memory and the QSPI mapped memory. How is this a h/w property? Why would I not want to always enable DMA if possible? Furthermore, you are reusing a property, but giving it a different meaning. The current definition is an indication whether a DMA controller supports memcpy operations or not. It is not a flag for clients to use memcpy channels. Why don't you use "dmas" property to point to the DMA controller. > + > Example: > > spi@f0020000 { > @@ -24,6 +28,7 @@ spi@f0020000 { > #size-cells = <0>; > pinctrl-names = "default"; > pinctrl-0 = <&pinctrl_spi0_default>; > + dmacap,memcpy; > > m25p80@0 { > ... > -- > 2.11.0 > > -- > To unsubscribe from this list: send the line "unsubscribe devicetree" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html