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[217.229.29.98]) by smtp.gmail.com with ESMTPSA id m14sm17431931wrs.76.2020.04.14.08.08.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Apr 2020 08:08:15 -0700 (PDT) Date: Tue, 14 Apr 2020 17:08:15 +0200 From: Thierry Reding To: Dmitry Osipenko Cc: Rob Herring , Jon Hunter , Michael Turquette , Stephen Boyd , Joseph Lo , linux-tegra@vger.kernel.org, devicetree@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v6 09/14] memory: tegra: Add EMC scaling support code for Tegra210 Message-ID: <20200414150815.GM3593749@ulmo> References: <20200409175238.3586487-1-thierry.reding@gmail.com> <20200409175238.3586487-10-thierry.reding@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="75WsOQSofUOhcSOp" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.13.1 (2019-12-14) Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org --75WsOQSofUOhcSOp Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Apr 10, 2020 at 05:25:06PM +0300, Dmitry Osipenko wrote: > 09.04.2020 20:52, Thierry Reding =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > ... > > +static int tegra210_emc_remove(struct platform_device *pdev) > > +{ > > + struct tegra210_emc *emc =3D platform_get_drvdata(pdev); > > + > > + debugfs_remove_recursive(emc->debugfs.root); > > + tegra210_clk_emc_detach(emc->clk); >=20 > It's great that you want to make this driver modular, but I don't think > that it's a good idea to suddenly rip off the EMC clock from the users. >=20 > It should be better to simply disallow unloading of this driver once > it's loaded. That's not what we're doing. The clock is going to stay around and users will be able to access it. The only thing that the above does is take away the possibility to change the rate of the EMC clock. So I think this actually makes this really nice both for testing that unload/reload works and it also gives users an easy way to disable EMC frequency scaling by simply blacklisting the module. 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