From nobody Thu Dec 18 18:24:04 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E4C8EE3F22 for ; Tue, 12 Sep 2023 20:22:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232454AbjILUWU (ORCPT ); Tue, 12 Sep 2023 16:22:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229496AbjILUWS (ORCPT ); Tue, 12 Sep 2023 16:22:18 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96670E4B for ; Tue, 12 Sep 2023 13:22:14 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPS id 2CFFCC433C7; Tue, 12 Sep 2023 20:22:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694550134; bh=SOwPjO8ogNZe+fryTz558cHWCx9nSaTQDFnAxRRRas0=; h=From:Date:Subject:To:Cc:Reply-To:From; b=W03PHTWwhHe3V4aWN62jOT7yQl7BK9ISkl7uzpxcpzEVadTZJ2YwhskOewMPnUq6R 4qO0sCcGyJqPTg0hpkvoCmre63ZdfJAKzCdVgT+UIF+VFCcdyYN7i398PTDaZnfd6z bL0JxZ+c/psF8gRotiZaEyYj5gYlflfREeWADKsSXCqLI0J6nndmuVZOSCGtGVIc2l fz/YNXwuTPKyd0e3t5cAQ27NJp1aeXQaq0KAYqXUKdhU0fDCGrXpYKqsRdvhidJEGU MYNzSCmt0kTKBUaBJtG8NpKl1qCyr9Q/gU8O70inphRKNdrmG63avGK65YA6HfQsgH 9DE+xnWVAo/WQ== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D678EE3F29; Tue, 12 Sep 2023 20:22:14 +0000 (UTC) From: Janne Grunau via B4 Relay Date: Tue, 12 Sep 2023 22:22:05 +0200 Subject: [PATCH v2] drm/simpledrm: Add support for multiple "power-domains" MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20230912-simpledrm-multiple-power-domains-v2-1-01b66bfb1980@jannau.net> X-B4-Tracking: v=1; b=H4sIAGzIAGUC/5WNQQ6CMBBFr0Jm7RiKiuDKexgWI53KGNqSFlBDu LuVG7j77y/eWyByEI5wyRYIPEsU7xIUuwzajtyDUXRiKPLikNcqxyh26FkHi3bqR0kbB//igNp bEhfRHBUbKknX9xaSZghs5L0lbk3iTuLow2crzur3/iGfFSo01VlVxKYtq9P1Sc7RtHc8QrOu6 xfOQqoA0QAAAA== To: Thomas Zimmermann , Javier Martinez Canillas , David Airlie , Daniel Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, asahi@lists.linux.dev, Janne Grunau X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=5966; i=j@jannau.net; h=from:subject:message-id; bh=++CkedQIUrBzc1lKOmCeLyAl+ixyBvXQdHhD4vxqutU=; b=owGbwMvMwCG2UNrmdq9+ahrjabUkhlSGEyW2vvVGhqHXdtQw/ft+hEn+Wkj+8ofiuf+sjt4/c Fhqs0RjRykLgxgHg6yYIkuS9ssOhtU1ijG1D8Jg5rAygQxh4OIUgInENjIytDEZlMmVBafybp6W 1BI0q3cK665daUd9525OPHHLKk/3LsM/vQdvPjl9aL2Z5LTx6PtdN/fWVuj3yixwViiaqjNHpD6 WAQA= X-Developer-Key: i=j@jannau.net; a=openpgp; fpr=8B336A6BE4E5695E89B8532B81E806F586338419 X-Endpoint-Received: by B4 Relay for j@jannau.net/default with auth_id=62 X-Original-From: Janne Grunau Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Janne Grunau Multiple power domains need to be handled explicitly in each driver. The driver core can not handle it automatically since it is not aware of power sequencing requirements the hardware might have. This is not a problem for simpledrm since everything is expected to be powered on by the bootloader. simpledrm has just ensure it remains powered on during its lifetime. This is required on Apple silicon M2 and M2 Pro/Max/Ultra desktop systems. The HDMI output initialized by the bootloader requires keeping the display controller and a DP phy power domain on. Signed-off-by: Janne Grunau Reviewed-by: Eric Curtin Reviewed-by: Javier Martinez Canillas Reviewed-by: Neal Gompa Reviewed-by: Sven Peter Reviewed-by: Thomas Zimmermann --- Changes in v2: - removed broken drm_err() log statement only ment for debugging - removed commented cast - use correct format spcifier for 'int' in log statement - add 'continue;' after failure to get device for power_domain - use drm_warn() in non fatal error cases - removed duplicate PTR_ERR conversion - Link to v1: https://lore.kernel.org/r/20230910-simpledrm-multiple-power-d= omains-v1-1-f8718aefc685@jannau.net --- drivers/gpu/drm/tiny/simpledrm.c | 105 +++++++++++++++++++++++++++++++++++= ++++ 1 file changed, 105 insertions(+) diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simple= drm.c index ff86ba1ae1b8..9c597461d1e2 100644 --- a/drivers/gpu/drm/tiny/simpledrm.c +++ b/drivers/gpu/drm/tiny/simpledrm.c @@ -6,6 +6,7 @@ #include #include #include +#include #include =20 #include @@ -227,6 +228,12 @@ struct simpledrm_device { unsigned int regulator_count; struct regulator **regulators; #endif + /* power-domains */ +#if defined CONFIG_OF && defined CONFIG_PM_GENERIC_DOMAINS + int pwr_dom_count; + struct device **pwr_dom_devs; + struct device_link **pwr_dom_links; +#endif =20 /* simplefb settings */ struct drm_display_mode mode; @@ -468,6 +475,101 @@ static int simpledrm_device_init_regulators(struct si= mpledrm_device *sdev) } #endif =20 +#if defined CONFIG_OF && defined CONFIG_PM_GENERIC_DOMAINS +/* + * Generic power domain handling code. + * + * Here we handle the power-domains properties of our "simple-framebuffer" + * dt node. This is only necessary if there is more than one power-domain. + * A single power-domains is handled automatically by the driver core. Mul= tiple + * power-domains have to be handled by drivers since the driver core can't= know + * the correct power sequencing. Power sequencing is not an issue for simp= ledrm + * since the bootloader has put the power domains already in the correct s= tate. + * simpledrm has only to ensure they remain active for its lifetime. + * + * When the driver unloads, we detach from the power-domains. + * + * We only complain about errors here, no action is taken as the most like= ly + * error can only happen due to a mismatch between the bootloader which set + * up the "simple-framebuffer" dt node, and the PM domain providers in the + * device tree. Chances are that there are no adverse effects, and if ther= e are, + * a clean teardown of the fb probe will not help us much either. So just + * complain and carry on, and hope that the user actually gets a working f= b at + * the end of things. + */ +static void simpledrm_device_detach_genpd(void *res) +{ + int i; + struct simpledrm_device *sdev =3D res; + + if (sdev->pwr_dom_count <=3D 1) + return; + + for (i =3D sdev->pwr_dom_count - 1; i >=3D 0; i--) { + if (!sdev->pwr_dom_links[i]) + device_link_del(sdev->pwr_dom_links[i]); + if (!IS_ERR_OR_NULL(sdev->pwr_dom_devs[i])) + dev_pm_domain_detach(sdev->pwr_dom_devs[i], true); + } +} + +static int simpledrm_device_attach_genpd(struct simpledrm_device *sdev) +{ + struct device *dev =3D sdev->dev.dev; + int i; + + sdev->pwr_dom_count =3D of_count_phandle_with_args(dev->of_node, "power-d= omains", + "#power-domain-cells"); + /* + * Single power-domain devices are handled by driver core nothing to do + * here. The same for device nodes without "power-domains" property. + */ + if (sdev->pwr_dom_count <=3D 1) + return 0; + + sdev->pwr_dom_devs =3D devm_kcalloc(dev, sdev->pwr_dom_count, + sizeof(*sdev->pwr_dom_devs), + GFP_KERNEL); + if (!sdev->pwr_dom_devs) + return -ENOMEM; + + sdev->pwr_dom_links =3D devm_kcalloc(dev, sdev->pwr_dom_count, + sizeof(*sdev->pwr_dom_links), + GFP_KERNEL); + if (!sdev->pwr_dom_links) + return -ENOMEM; + + for (i =3D 0; i < sdev->pwr_dom_count; i++) { + sdev->pwr_dom_devs[i] =3D dev_pm_domain_attach_by_id(dev, i); + if (IS_ERR(sdev->pwr_dom_devs[i])) { + int ret =3D PTR_ERR(sdev->pwr_dom_devs[i]); + if (ret =3D=3D -EPROBE_DEFER) { + simpledrm_device_detach_genpd(sdev); + return ret; + } + drm_warn(&sdev->dev, + "pm_domain_attach_by_id(%u) failed: %d\n", i, ret); + continue; + } + + sdev->pwr_dom_links[i] =3D device_link_add(dev, + sdev->pwr_dom_devs[i], + DL_FLAG_STATELESS | + DL_FLAG_PM_RUNTIME | + DL_FLAG_RPM_ACTIVE); + if (!sdev->pwr_dom_links[i]) + drm_warn(&sdev->dev, "failed to link power-domain %d\n", i); + } + + return devm_add_action_or_reset(dev, simpledrm_device_detach_genpd, sdev); +} +#else +static int simpledrm_device_attach_genpd(struct simpledrm_device *sdev) +{ + return 0; +} +#endif + /* * Modesetting */ @@ -651,6 +753,9 @@ static struct simpledrm_device *simpledrm_device_create= (struct drm_driver *drv, if (ret) return ERR_PTR(ret); ret =3D simpledrm_device_init_regulators(sdev); + if (ret) + return ERR_PTR(ret); + ret =3D simpledrm_device_attach_genpd(sdev); if (ret) return ERR_PTR(ret); =20 --- base-commit: 15d30b46573d75f5cb58cfacded8ebab9c76a2b0 change-id: 20230910-simpledrm-multiple-power-domains-f41efa6ad9bc Best regards, --=20 Janne Grunau