Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757257AbaGWN73 (ORCPT ); Wed, 23 Jul 2014 09:59:29 -0400 Received: from mail-pa0-f42.google.com ([209.85.220.42]:56582 "EHLO mail-pa0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752799AbaGWN7Z (ORCPT ); Wed, 23 Jul 2014 09:59:25 -0400 Date: Wed, 23 Jul 2014 15:59:20 +0200 From: Thierry Reding To: Tuomas Tynkkynen Cc: "linux-tegra@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-pm@vger.kernel.org" , Stephen Warren , Peter De Schrijver , Prashant Gaikwad , Mike Turquette , "Rafael J. Wysocki" , Viresh Kumar , Paul Walmsley , "devicetree@vger.kernel.org" Subject: Re: [PATCH v2 14/16] cpufreq: Add cpufreq driver for Tegra124 Message-ID: <20140723135918.GC14263@ulmo.nvidia.com> References: <1405957142-19416-1-git-send-email-ttynkkynen@nvidia.com> <1405957142-19416-15-git-send-email-ttynkkynen@nvidia.com> <20140723070949.GB15759@ulmo.nvidia.com> <53CFAC22.40106@nvidia.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="adJ1OR3c6QgCpb/j" Content-Disposition: inline In-Reply-To: <53CFAC22.40106@nvidia.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --adJ1OR3c6QgCpb/j Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jul 23, 2014 at 03:35:46PM +0300, Tuomas Tynkkynen wrote: > On 23/07/14 10:09, Thierry Reding wrote: > > On Mon, Jul 21, 2014 at 06:39:00PM +0300, Tuomas Tynkkynen wrote: [...] > >> diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegr= a124-cpufreq.c [...] > >> + cpu_clk =3D of_clk_get_by_name(cpu_dev->of_node, "cpu_g"); > >> + if (IS_ERR(cpu_clk)) > >> + return PTR_ERR(cpu_clk); [...] > >> + pllp_clk =3D of_clk_get_by_name(cpu_dev->of_node, "pll_p"); > >> + if (IS_ERR(pllp_clk)) { > >> + ret =3D PTR_ERR(pllp_clk); > >> + goto out_put_pllx_clk; > >> + } > >=20 > > Can the above not be devm_clk_get(cpu_dev, "...") so that you can remove > > all the clk_put() calls in the cleanup code below? >=20 > That would allocate the clks under the cpu_dev's devres list, i.e. all the > clk_puts wouldn't happen when the cpufreq driver goes away, but only when > cpu_dev itself goes away. I don't think so. devres_release_all() is called on driver detach as well. > > But is there even a reason why we need that? Couldn't we make the > > driver's .remove() undo what .probe() did so that the driver can be > > unloaded? >=20 > I guess that could be done, though to fully undo everything the regulator > voltage would also need to be saved/restored. That would certainly be my prefered approach. that way the driver can simply be unloaded, leaving the CPU in the same state as it was after boot. > > Otherwise it probably makes more sense not to use a driver (and dummy > > device) at all as Viresh already mentioned. > >=20 >=20 > The dummy platform device is only required for probe deferral, if that > could be solved in a different way then yes. I don't think it can. Probe deferral is pretty closely tied to devices so it's unlikely to ever get implemented for regular initcalls. And in this case I really think making the driver removable is a good thing. > >> +}; > >> + > >> +static const struct of_device_id soc_of_matches[] =3D { > >> + { .compatible =3D "nvidia,tegra124", }, > >> + {} > >> +}; > >> + > >> +static int __init tegra_cpufreq_init(void) > >> +{ > >> + int ret; > >> + struct platform_device *pdev; > >> + > >> + if (!of_find_matching_node(NULL, soc_of_matches)) > >> + return -ENODEV; > >=20 > > I think this could be of_machine_is_compatible() since there's only a > > single entry in the match table. If there's a good chance that we may > > end up with more entries, perhaps now would be a good time to add an > > of_match_machine() function? >=20 > I think this driver should work on Tegra132 without modifications. > of_match_machine() does sound useful for some of the other cpufreq > drivers as well and likely for your soc_is_tegra() from the PMC > series as well. Yes, indeed. I'll give it a shot if you don't beat me to it with this series. Thierry --adJ1OR3c6QgCpb/j Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJTz7+2AAoJEN0jrNd/PrOh+8QQAIc/DP10tF6BRPMbqKvsvKyp v7Wfj5fN9DRs9HYH/QPquxC1rt+GK2TCWMx/D9SbaIBakvwjMBQuLuPCr6dAC3L5 2xx7REzr83DKtXtb92j3i6AA53fw2bmh4k1kwBK9hiRIKPV8K89LoPK3s9bLU0ws ra8+LBmtwq6ZpKBJ59vWHQxdV0hk8tQu78z1/VWs+neOt2mvoOZ1cKO/gMVvYso7 Ryb1C6MYjNrkqTLNsj1NDkdhEsGSErc0nTjYsZHLGGTWp0hR/LmkPbhcdF/WbuAq RW61E+3+3ky+P9S/EPKm8wP14zS9RAxh5DNgOfoG1LYWWruzu87XdCxtPgqML8gH 7mGMvtbjTUSnD3NDMxjzGOW2CUCFhwehNJzws4H2JX1c/P6fapGkAoniAgHPuowq hF4BBVWdC4F9H4lBCPRBDYPH0B5X9dbdvHHIrKsDm9GETWqnyeO4hSJ+kjp9WHUF zRH7azliBlbdBsWU4UWd/SV7O+NQqYbAO5AyGMPX9Ji5iFISTKi2mhFy5YCubIQM FheuX+Ehp/3Mx1n9B3hQlufO5/1nn0mw0aHRRamSJOZxWicUQqpwCLztVLGjNwjM Oqe3AhtpX/m4uetKbip9OAsyPo29Yot0pypdTEQpscqhcup5bprCiRzxjAxec/qb yeuhwhVidhQXbn4vHCQ9 =i8Iv -----END PGP SIGNATURE----- --adJ1OR3c6QgCpb/j-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/