Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756675AbcK3KLl (ORCPT ); Wed, 30 Nov 2016 05:11:41 -0500 Received: from www381.your-server.de ([78.46.137.84]:60636 "EHLO www381.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752857AbcK3KKu (ORCPT ); Wed, 30 Nov 2016 05:10:50 -0500 Subject: Re: [PATCH] iio: misc: add a generic regulator driver To: Bartosz Golaszewski References: <1480432969-20913-1-git-send-email-bgolaszewski@baylibre.com> <44cce3d5-f65e-1a35-20a4-5eb9fda42312@metafoo.de> Cc: Jonathan Cameron , Hartmut Knaack , Peter Meerwald-Stadler , Rob Herring , Mark Rutland , linux-iio@vger.kernel.org, linux-devicetree , LKML , Kevin Hilman , Patrick Titiano , Neil Armstrong From: Lars-Peter Clausen X-Enigmail-Draft-Status: N1110 Message-ID: Date: Wed, 30 Nov 2016 11:10:36 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Authenticated-Sender: lars@metafoo.de Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1552 Lines: 33 On 11/29/2016 04:35 PM, Bartosz Golaszewski wrote: > 2016-11-29 16:30 GMT+01:00 Lars-Peter Clausen : >> On 11/29/2016 04:22 PM, Bartosz Golaszewski wrote: >> [...] >>> diff --git a/Documentation/devicetree/bindings/iio/misc/iio-regulator.txt b/Documentation/devicetree/bindings/iio/misc/iio-regulator.txt >>> new file mode 100644 >>> index 0000000..147458f >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/iio/misc/iio-regulator.txt >>> @@ -0,0 +1,18 @@ >>> +Industrial IO regulator device driver >>> +------------------------------------- >>> + >>> +This document describes the bindings for the iio-regulator - a dummy device >>> +driver representing a physical regulator within the iio framework. >> >> No bindings for drivers, only for hardware. So this wont work. >> > > What about exporting regulator attributes analogous to the one in this > patch from the iio-core when a *-supply property is specified for a > node? The problem with exposing direct control to the regulator is that it allows to modify the hardware state without the drivers knowledge. If you power-cycle a device all previous configuration that has been written to the device is reset. The device driver needs to be aware of this otherwise its assumed state and the actual device state can divert which will result in undefined behavior. Also access to the device will fail unexpectedly when the regulator is turned off. So I think generally the driver should explicitly control the regulator, power-up when needed, power-down when not. - Lars