From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85F81FC6182 for ; Fri, 14 Sep 2018 10:38:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45CE320882 for ; Fri, 14 Sep 2018 10:38:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 45CE320882 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728261AbeINPwR (ORCPT ); Fri, 14 Sep 2018 11:52:17 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:49221 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726893AbeINPwR (ORCPT ); Fri, 14 Sep 2018 11:52:17 -0400 Received: from lupine.hi.pengutronix.de ([2001:67c:670:100:3ad5:47ff:feaf:1a17] helo=lupine) by metis.ext.pengutronix.de with esmtp (Exim 4.89) (envelope-from ) id 1g0lUN-0004Cd-E5; Fri, 14 Sep 2018 12:38:15 +0200 Message-ID: <1536921493.4112.6.camel@pengutronix.de> Subject: Re: [PATCH] ARC: HSDK: improve reset driver From: Philipp Zabel To: Eugeniy Paltsev Cc: linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org, Alexey Brodkin Date: Fri, 14 Sep 2018 12:38:13 +0200 In-Reply-To: <20180827143803.28178-1-Eugeniy.Paltsev@synopsys.com> References: <20180827143803.28178-1-Eugeniy.Paltsev@synopsys.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:100:3ad5:47ff:feaf:1a17 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Eugeniy, On Mon, 2018-08-27 at 17:38 +0300, Eugeniy Paltsev wrote: > As for today HSDK reset driver implements only > .reset() callback. > > In case of driver which implements one of standard > reset controller usage pattern > (call *_deassert() in probe(), call *_assert() in remove()) > that leads to inoperability of this reset driver. > > Improve HSDK reset driver by calling .reset() callback inside of > .assert()/.deassert() callbacks to avoid each reset controller > user adaptation for work with both reset methods > (reset() and .assert()/.deassert() pair) > > Signed-off-by: Eugeniy Paltsev > --- > drivers/reset/reset-hsdk.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/reset/reset-hsdk.c b/drivers/reset/reset-hsdk.c > index 8bce391c6943..1fd91df91343 100644 > --- a/drivers/reset/reset-hsdk.c > +++ b/drivers/reset/reset-hsdk.c > @@ -86,6 +86,8 @@ static int hsdk_reset_reset(struct reset_controller_dev *rcdev, > > static const struct reset_control_ops hsdk_reset_ops = { > .reset = hsdk_reset_reset, > + .assert = hsdk_reset_reset, This is incorrect for exclusive reset controls. It will cause reset_control_assert() to return success for exclusive reset controls, even though the .assert op failed to leave the reset line asserted after the function returns. While calling hsdk_reset_reset from .assert for shared reset controls would be fine, I don't see how this is necessary of useful. If a consumer driver requires the reset to be asserted upon remove(), it must not request a shared reset control anyway, because with shared reset controls other drivers may keep the reset line deasserted indefinitely. > + .deassert = hsdk_reset_reset, This should be fine. I wonder from time to time whether this should be implemented in the core, in reset_control_deassert(). regards Philipp