From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754798AbbBOPqG (ORCPT ); Sun, 15 Feb 2015 10:46:06 -0500 Received: from kirsty.vergenet.net ([202.4.237.240]:37051 "EHLO kirsty.vergenet.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751013AbbBOPqD (ORCPT ); Sun, 15 Feb 2015 10:46:03 -0500 Date: Sun, 15 Feb 2015 10:45:57 -0500 From: Simon Horman To: Geert Uytterhoeven Cc: Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Grant Likely , Arnd Bergmann , Kevin Hilman , Ulf Hansson , "Rafael J. Wysocki" , Felipe Balbi , Olof Johansson , Magnus Damm , Greg Kroah-Hartman , devicetree@vger.kernel.org, linux-sh@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 0/5] drivers: bus: Add Simple Power-Managed Bus Message-ID: <20150215154556.GD25065@verge.net.au> References: <1423131088-7835-1-git-send-email-geert+renesas@glider.be> <20150211001835.GB7826@verge.net.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150211001835.GB7826@verge.net.au> Organisation: Horms Solutions Ltd. User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 11, 2015 at 09:18:35AM +0900, Simon Horman wrote: > Hi Geert, > > On Thu, Feb 05, 2015 at 11:11:23AM +0100, Geert Uytterhoeven wrote: > > Hi all, > > > > The Renesas Bus State Controller (BSC) provides an external bus for > > connecting multiple external devices to an SoC, driving several chip > > select lines, for e.g. NOR FLASH, Ethernet and USB. > > On the kzm9g and ape6evm development boards, an smsc9220 Ethernet > > controller is connnected to the BSC of an SH-Mobile AG5 (sh73a0) resp. > > R-Mobile APE6 (r8a73a4) SoC. > > > > The BSC is a fairly simple memory-mapped bus, hence a "simple-bus" > > compatibility seems suitable. However, the BSC is special in two > > ways: > > 1. It is part of a PM domain (A4S on sh73a0), > > 2. It has a gateable functional clock (ZB). > > Before a device connected to the BSC can be accessed, the PM domain > > containing the BSC must be powered on, and the functional clock > > driving the BSC must be enabled. > > > > Both special properties can be described in DT in a standardized way > > ("power-domains = <&pd_a4s>" and "clocks = <&zb_clk>", cfr. the > > example in the DT binding documentation). Externally connected > > devices are described as children of the BSC node. > > > > Unfortunately this doesn't mean everything will work out-of-the-box. > > There are two problems: > > 1. Without a device driver bound to the bus device, this device is > > not attached to the PM domain. And although a child device is > > present and active, the PM domain may be powered down, as it's > > considered unused by the PM domain core. > > 2. Without a device driver calling pm_runtime_enable(), its > > functional clock is not enabled. Once runtime PM is enabled, the > > R-Mobile PM domain platform driver manages the functional clock > > using runtime PM. > > > > As none of the above is really bus hardware-specific (PM domains and > > functional clocks in clock domains are handled from genpd and platform > > code), this series adds a Simple Power-Managed Bus driver for > > transparent busses, which matches against "simple-pm-bus", enables > > runtime PM for the bus device, and calls of_platform_populate() to > > probe for child devices. > > Due to the child-parent relationship of devices connected to the bus, > > as long as the device drivers for the child devices are runtime PM > > enabled, the bus's PM domain will be powered, and the bus's clock will > > be enabled automatically when needed, for both runtime PM and s2ram. > > > > This was tested on sh73a0/kzm9g-multiplatform (by me), and (v3) on > > r8a73a4/ape6evm-multiplatform (by Ulrich Hecht). Without this, > > Ethernet doesn't work, as the ZB clock is disabled by > > clk_disable_unused(). > > > > Felipe: It looks like drivers/usb/musb/musb_am335x.c can be removed, if > > "ti,am33xx-usb" claims compatibility with "simple-pm-bus"? > > > > As drivers/bus doesn't have a maintainer, and this driver is needed to > > move two shmobile platforms away from legacy to multiplatform, I think > > this can go in through Simon's shmobile tree. > > thanks for persisting with this. From my point of view it appears > to be reviewed and ready. > > Does anyone object to me queueing this up for v3.21 in the renesas tree? > > Acked-by: Simon Horman As no one has objected and it seems has been thoroughly reviewed I have queued this up in the renesas tree. It is part of the renesas-devel-20150215-v3.19 tag. [snip]