From patchwork Thu Jun 25 12:00:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Zimmermann X-Patchwork-Id: 11624967 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D27BA913 for ; Thu, 25 Jun 2020 12:00:27 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B9EF1204EC for ; Thu, 25 Jun 2020 12:00:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B9EF1204EC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 18E806EBBB; Thu, 25 Jun 2020 12:00:18 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6E7896EBBB for ; Thu, 25 Jun 2020 12:00:16 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5C0F7AEAC; Thu, 25 Jun 2020 12:00:14 +0000 (UTC) From: Thomas Zimmermann To: maarten.lankhorst@linux.intel.com, mripard@kernel.org, airlied@linux.ie, daniel@ffwll.ch, kraxel@redhat.com, lgirdwood@gmail.com, broonie@kernel.org, robh@kernel.org, sam@ravnborg.org, emil.l.velikov@gmail.com, noralf@tronnes.org, geert+renesas@glider.be, hdegoede@redhat.com Subject: [PATCH 6/9] drm/simplekms: Acquire clocks from DT device node Date: Thu, 25 Jun 2020 14:00:08 +0200 Message-Id: <20200625120011.16168-7-tzimmermann@suse.de> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200625120011.16168-1-tzimmermann@suse.de> References: <20200625120011.16168-1-tzimmermann@suse.de> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Zimmermann , dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Make sure required hardware clocks are enabled while the firmware framebuffer is in use. The basic code has been taken from the simplefb driver and adapted to DRM. Clocks are released automatically via devres helpers. Signed-off-by: Thomas Zimmermann --- drivers/gpu/drm/tiny/simplekms.c | 108 +++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) diff --git a/drivers/gpu/drm/tiny/simplekms.c b/drivers/gpu/drm/tiny/simplekms.c index 87636307aa4f..aca186decb48 100644 --- a/drivers/gpu/drm/tiny/simplekms.c +++ b/drivers/gpu/drm/tiny/simplekms.c @@ -1,5 +1,7 @@ // SPDX-License-Identifier: GPL-2.0-only +#include +#include #include #include @@ -191,6 +193,12 @@ struct simplekms_device { struct drm_device dev; struct platform_device *pdev; + /* clocks */ +#if defined CONFIG_OF && defined CONFIG_COMMON_CLK + unsigned int clk_count; + struct clk **clks; +#endif + /* simplefb settings */ struct drm_display_mode mode; const struct drm_format_info *format; @@ -210,6 +218,103 @@ static struct simplekms_device *simplekms_device_of_dev(struct drm_device *dev) return container_of(dev, struct simplekms_device, dev); } +/* + * Hardware + */ + +#if defined CONFIG_OF && defined CONFIG_COMMON_CLK +/* + * Clock handling code. + * + * Here we handle the clocks property of our "simple-framebuffer" dt node. + * This is necessary so that we can make sure that any clocks needed by + * the display engine that the bootloader set up for us (and for which it + * provided a simplefb dt node), stay up, for the life of the simplefb + * driver. + * + * When the driver unloads, we cleanly disable, and then release the clocks. + * + * We only complain about errors here, no action is taken as the most likely + * error can only happen due to a mismatch between the bootloader which set + * up simplefb, and the clock definitions in the device tree. Chances are + * that there are no adverse effects, and if there 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 fb at the end of things. + */ + +static void simplekms_device_release_clocks(void *res) +{ + struct simplekms_device *sdev = simplekms_device_of_dev(res); + unsigned int i; + + for (i = 0; i < sdev->clk_count; ++i) { + if (sdev->clks[i]) { + clk_disable_unprepare(sdev->clks[i]); + clk_put(sdev->clks[i]); + } + } +} + +static int simplekms_device_init_clocks(struct simplekms_device *sdev) +{ + struct drm_device *dev = &sdev->dev; + struct platform_device *pdev = sdev->pdev; + struct device_node *of_node = pdev->dev.of_node; + struct clk *clock; + unsigned int i; + int ret; + + if (dev_get_platdata(&pdev->dev) || !of_node) + return 0; + + sdev->clk_count = of_clk_get_parent_count(of_node); + if (!sdev->clk_count) + return 0; + + sdev->clks = drmm_kzalloc(dev, sdev->clk_count * sizeof(sdev->clks[0]), + GFP_KERNEL); + if (!sdev->clks) + return -ENOMEM; + + for (i = 0; i < sdev->clk_count; ++i) { + clock = of_clk_get(of_node, i); + if (IS_ERR(clock)) { + ret = PTR_ERR(clock); + if (ret == -EPROBE_DEFER) + goto err; + drm_err(dev, "clock %u not found: %d\n", i, ret); + continue; + } + ret = clk_prepare_enable(clock); + if (ret) { + drm_err(dev, "failed to enable clock %u: %d\n", + i, ret); + clk_put(clock); + } + sdev->clks[i] = clock; + } + + return devm_add_action_or_reset(&pdev->dev, + simplekms_device_release_clocks, + sdev); + +err: + while (i) { + --i; + if (sdev->clks[i]) { + clk_disable_unprepare(sdev->clks[i]); + clk_put(sdev->clks[i]); + } + } + return ret; +} +#else +static int simplekms_device_init_clocks(struct simplekms_device *sdev) +{ + return 0; +} +#endif + /* * Simplefb settings */ @@ -505,6 +610,9 @@ simplekms_device_create(struct drm_driver *drv, struct platform_device *pdev) return ERR_CAST(sdev); sdev->pdev = pdev; + ret = simplekms_device_init_clocks(sdev); + if (ret) + return ERR_PTR(ret); ret = simplekms_device_init_fb(sdev); if (ret) return ERR_PTR(ret);