From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DF9DC169C4 for ; Thu, 31 Jan 2019 13:26:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70A60218FC for ; Thu, 31 Jan 2019 13:26:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387516AbfAaN0Q (ORCPT ); Thu, 31 Jan 2019 08:26:16 -0500 Received: from relay11.mail.gandi.net ([217.70.178.231]:35231 "EHLO relay11.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733072AbfAaN0P (ORCPT ); Thu, 31 Jan 2019 08:26:15 -0500 X-Greylist: delayed 75339 seconds by postgrey-1.27 at vger.kernel.org; Thu, 31 Jan 2019 08:26:14 EST Received: from localhost.localdomain (aaubervilliers-681-1-27-226.w90-88.abo.wanadoo.fr [90.88.147.226]) (Authenticated sender: paul.kocialkowski@bootlin.com) by relay11.mail.gandi.net (Postfix) with ESMTPSA id F3809100012; Thu, 31 Jan 2019 13:26:11 +0000 (UTC) From: Paul Kocialkowski To: dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com Cc: Maxime Ripard , David Airlie , Chen-Yu Tsai , Maxime Ripard , Paul Kocialkowski Subject: [PATCH] drm/sun4i: tcon: Prepare and enable TCON channel 0 clock at init Date: Thu, 31 Jan 2019 14:25:50 +0100 Message-Id: <20190131132550.26355-1-paul.kocialkowski@bootlin.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When initializing clocks, a reference to the TCON channel 0 clock is obtained. However, the clock is never prepared and enabled later. Switching from simplefb to DRM actually disables the clock (that was usually configured by U-Boot) because of that. On the V3s, this results in a hang when writing to some mixer registers when switching over to DRM from simplefb. Fix this by preparing and enabling the clock when initializing other clocks. Waiting for sun4i_tcon_channel_enable to enable the clock is apparently too late and results in the same mixer register access hang. Signed-off-by: Paul Kocialkowski --- drivers/gpu/drm/sun4i/sun4i_tcon.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index e987615c16f1..b31f5d95cadb 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -371,6 +371,7 @@ static int sun4i_tcon_init_clocks(struct device *dev, dev_err(dev, "Couldn't get the TCON channel 0 clock\n"); return PTR_ERR(tcon->sclk0); } + clk_prepare_enable(tcon->sclk0); if (tcon->quirks->has_channel_1) { tcon->sclk1 = devm_clk_get(dev, "tcon-ch1"); @@ -385,6 +386,7 @@ static int sun4i_tcon_init_clocks(struct device *dev, static void sun4i_tcon_free_clocks(struct sun4i_tcon *tcon) { + clk_disable_unprepare(tcon->sclk0); clk_disable_unprepare(tcon->clk); } -- 2.20.1