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[209.132.180.67]) by mx.google.com with ESMTP id e21-v6si17959619pgl.305.2018.10.17.07.21.04; Wed, 17 Oct 2018 07:21:21 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727534AbeJQWQ3 (ORCPT + 99 others); Wed, 17 Oct 2018 18:16:29 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:43295 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726727AbeJQWQ2 (ORCPT ); Wed, 17 Oct 2018 18:16:28 -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 1gCmga-0001dQ-5Q; Wed, 17 Oct 2018 16:20:32 +0200 Message-ID: <1539786031.4729.7.camel@pengutronix.de> Subject: Re: [PATCH v2] ARC: HSDK: improve reset driver From: Philipp Zabel To: Eugeniy Paltsev Cc: "linux-kernel@vger.kernel.org" , "alexey.brodkin@synopsys.com" , "linux-snps-arc@lists.infradead.org" Date: Wed, 17 Oct 2018 16:20:31 +0200 In-Reply-To: <1539784482.4199.35.camel@synopsys.com> References: <20180928162856.4726-1-Eugeniy.Paltsev@synopsys.com> <1539346114.6204.5.camel@pengutronix.de> <1539784482.4199.35.camel@synopsys.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit 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 Wed, 2018-10-17 at 13:54 +0000, Eugeniy Paltsev wrote: [...] > > The documentation states that calling reset_control_assert "on an > > exclusive reset controller guarantees that the reset will be asserted." > > Since this is clearly not the case with this driver, it is appropriate > > to keep returning an error in this case. > > > > If there is a driver that requests an exclusive reset control, calls > > reset_control_assert, and then checks the error value to see whether > > asserting the reset succeeded, it should be made aware that > > we couldn't actually assert the reset line as requested. If the driver > > can continue operation even though the reset line was not asserted, > > it should ignore the error. > > > > So if you need to hide this error, I'd like to know the actual case that > > is fixed by this, to see if we can't fix it in a better way. > > Ok, I can drop it in my case as it will work fine with certain drivers: > (several drivers use shared reset control, other drivers use exclusive reset > control but don't check reset_control_assert() return value) > > I simply want to say that this wouldn't work in all cases (without changes > in driver which use reset control). Ok, if there is ever such a case, please let me know. regards Philipp