From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422649AbcKPJhn (ORCPT ); Wed, 16 Nov 2016 04:37:43 -0500 Received: from mirror2.csie.ntu.edu.tw ([140.112.30.76]:36434 "EHLO wens.csie.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752886AbcKPJhj (ORCPT ); Wed, 16 Nov 2016 04:37:39 -0500 From: Chen-Yu Tsai To: Maxime Ripard , David Airlie Cc: linux-sunxi@googlegroups.com, Chen-Yu Tsai , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] drm/sun4i: tcon: Initialize regmap after enabling bus clocks Date: Wed, 16 Nov 2016 17:37:32 +0800 Message-Id: <20161116093732.12828-2-wens@csie.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161116093732.12828-1-wens@csie.org> References: <20161116093732.12828-1-wens@csie.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we attempt to read/write the TCON registers before the bus clock is enabled, those accesses get ignored. In practice this almost never occurs because U-boot had already enabled the bus clock as part of its firmware provided framebuffer (simplefb). Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support") Signed-off-by: Chen-Yu Tsai --- I was looking around the DRM driver and noticed this sequence was off. --- drivers/gpu/drm/sun4i/sun4i_tcon.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index c6afb2448655..8c2db65ea229 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -506,16 +506,16 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master, return ret; } - ret = sun4i_tcon_init_regmap(dev, tcon); + ret = sun4i_tcon_init_clocks(dev, tcon); if (ret) { - dev_err(dev, "Couldn't init our TCON regmap\n"); + dev_err(dev, "Couldn't init our TCON clocks\n"); goto err_assert_reset; } - ret = sun4i_tcon_init_clocks(dev, tcon); + ret = sun4i_tcon_init_regmap(dev, tcon); if (ret) { - dev_err(dev, "Couldn't init our TCON clocks\n"); - goto err_assert_reset; + dev_err(dev, "Couldn't init our TCON regmap\n"); + goto err_free_clocks; } ret = sun4i_tcon_init_irq(dev, tcon); -- 2.10.2