From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933095AbaFQOZa (ORCPT ); Tue, 17 Jun 2014 10:25:30 -0400 Received: from mail-ig0-f169.google.com ([209.85.213.169]:52874 "EHLO mail-ig0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932585AbaFQOZ2 (ORCPT ); Tue, 17 Jun 2014 10:25:28 -0400 Date: Tue, 17 Jun 2014 15:25:06 +0100 From: Lee Jones To: Philipp Zabel Cc: devicetree@vger.kernel.org, Rob Herring , Pawel Moll , Mark Rutland , linux-kernel@vger.kernel.org, kernel@pengutronix.de Subject: Re: [RFC PATCH] mfd: syscon: add child device support Message-ID: <20140617142506.GA29841@lee--X1> References: <1401198917-16077-1-git-send-email-p.zabel@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1401198917-16077-1-git-send-email-p.zabel@pengutronix.de> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org FAO DT chaps, I'd be interested to hear your opinion about this. > For devices which have a complete register for themselves, it is possible to > place them next to the syscon device with overlapping reg ranges. The same is > not possible for devices which only occupy bitfields in registers shared with > other users. > For devices that are completely controlled by bitfields in the syscon address > range, such as multiplexers or voltage regulators, allow to put child devices > into the syscon device node. > > Signed-off-by: Philipp Zabel > --- > Documentation/devicetree/bindings/mfd/syscon.txt | 11 +++++++++++ > drivers/mfd/syscon.c | 2 ++ > 2 files changed, 13 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt > index fe8150b..a7e11d5 100644 > --- a/Documentation/devicetree/bindings/mfd/syscon.txt > +++ b/Documentation/devicetree/bindings/mfd/syscon.txt > @@ -9,10 +9,21 @@ using a specific compatible value), interrogate the node (or associated > OS driver) to determine the location of the registers, and access the > registers directly. > > +Optionally, devices that are only controlled through single syscon > +registers or bitfields can also be added as child nodes to the syscon > +device node. These devices can implicitly assume their parent node > +as syscon provider without referencing it explicitly via phandle. > +In this case, the syscon node should have #address-cells = <1> and > +#size-cells = <0> and no ranges property. > + > Required properties: > - compatible: Should contain "syscon". > - reg: the register region can be accessed from syscon > > +Optional properties: > +- #address-cells: Should be 1. > +- #size-cells: Should be 0. > + > Examples: > gpr: iomuxc-gpr@020e0000 { > compatible = "fsl,imx6q-iomuxc-gpr", "syscon"; > diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c > index dbea55d..1dde475 100644 > --- a/drivers/mfd/syscon.c > +++ b/drivers/mfd/syscon.c > @@ -147,6 +147,8 @@ static int syscon_probe(struct platform_device *pdev) > > dev_dbg(dev, "regmap %pR registered\n", res); > > + of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); > + > return 0; > } > -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog