From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1525687298; cv=none; d=google.com; s=arc-20160816; b=BQ/4kvCM2zisBRdFDH8189P0z2wqkNaYj2GazDUA404zBJwmQ6LofWvKo/eBj1dtyq wZ1wSGc4JDUfgFDPIKSu89sxFaHcHBfCBgw/EmTkLiS2aFF4igh1+gRTS+DfBiXRGsh4 wnr0VZ3TkRD/td0N1i1wfC5rnx27BO5E3TvRcYc0UHuRye//HPMb/nix+IAwHw5Lc9fb s6wgtP0PmG9UmH1DC4eUiTvq1lCqz0CvMUFzYfJr4fuLvwKvrn4NNtYn/vb+EtUrcqrt OXI8xFR+wgBzfoA9CcuA/sWR2s1FK2IzHsJ70LcPw1Ca4ulMawNhzJv2xWZQ/a4yoXet ylVA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:sender:dkim-signature :arc-authentication-results; bh=04FKQ28tq2c8hsfvCPSvCWOd/dNkbTCoU5DcvHkDd+Q=; b=oEdxgI6xSq1UAhqPpw34AU2OU66eKBUr12DWWG1BuZFTRxNygLHIvjlz+hb2yc0eCF +b2PYYQyorMTkrGZBYhGD7w2SHPsV2dxmocOblMEDmMeYKqUVUPL5bX2sW34KM1HvNy0 CGA+/0YhRnXGaKit6bdpP/s9k3xYVQQKn/2ae6A44D8G1nZUxWzqaa9Ryx2/CRMp3H5+ zJ7N55FIlLMABjoMp7wXNcZxa9C7puj1JKY+1sN7dVqw8M6N4nYA+7Q2AHn/oCbv9qF3 Hd4C+ffHM14wx5snJtFcSt1DyUyNrKrjNFKDRynX/PmrZcx7v18whtnTLLBjp/sAUD70 QIbA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=XxCV36Qw; spf=pass (google.com: domain of jhovold@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=jhovold@gmail.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=XxCV36Qw; spf=pass (google.com: domain of jhovold@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=jhovold@gmail.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Google-Smtp-Source: AB8JxZrUyEeySOru0FXsR2kwu1SCPa5e7U/rwvjMtg6Y1lYm2S3D1GoyGIf2m8f9pxK+DJYyJngplw== Sender: Johan Hovold Date: Mon, 7 May 2018 12:01:35 +0200 From: Johan Hovold To: Sebastian Reichel Cc: "H. Nikolaus Schaller" , Andreas Kemnade , Johan Hovold , Mark Rutland , Arnd Bergmann , Pavel Machek , "linux-kernel@vger.kernel.org" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Greg Kroah-Hartman , Rob Herring , Tony Lindgren Subject: Re: [PATCH 4/7] dt-bindings: gnss: add u-blox binding Message-ID: <20180507100135.GS2285@localhost> References: <20180424163458.11947-1-johan@kernel.org> <20180424163458.11947-5-johan@kernel.org> <20180426091018.GU4615@localhost> <20180502081637.GE2285@localhost> <5242FCAD-3139-4A9C-B9FA-7BBAA0E6AE57@goldelico.com> <20180503205037.7be552c1@aktux> <44A0BC7C-67C7-4116-849F-90FF7CF2B1F0@goldelico.com> <20180504114213.3xlzqxe74n55tk5s@earth.universe> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180504114213.3xlzqxe74n55tk5s@earth.universe> User-Agent: Mutt/1.9.5 (2018-04-13) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1598647064088300079?= X-GMAIL-MSGID: =?utf-8?q?1599799084433598056?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Fri, May 04, 2018 at 01:42:13PM +0200, Sebastian Reichel wrote: > Having said all of this, serdev does not yet support runtime PM (at > all). Tony is currently looking into it. Fortunately serdev allows > us to enable runtime PM by default (once implemented), since we know > the remote side and can (hopefully) avoid losing characters (i.e. > with sideband wakeup gpios). I'm not sure we want generic runtime-pm support for the controllers in the sense that the slave device state is always reflected by the serial controller. Similar as for i2c and spi, we really only want to keep the controller active when we are doing I/O, but we may want to keep a client active for longer. Take the u-blox driver in this series for example. As I'm using runtime PM to manage device power, user-space can chose to prevent the receiver from runtime suspending in order to avoid lengthy (re-)acquisition times in setups without a backup battery (by means of the power/control attribute). Note that serdev not enabling runtime pm for controllers is roughly equivalent to setting the .ignore_children flag, which is what we do for i2c and spi controller, and possibly what we want here too. Thanks, Johan