From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.82]:27965 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732699AbeHNQh7 (ORCPT ); Tue, 14 Aug 2018 12:37:59 -0400 From: Ulrich Hecht To: laurent.pinchart@ideasonboard.com Cc: linux-renesas-soc@vger.kernel.org, dri-devel@lists.freedesktop.org, jacopo+renesas@jmondi.org, kieran.bingham+renesas@ideasonboard.com, Ulrich Hecht Subject: [PROTO][PATCH 08/10] drm: rcar-du: lvds: Handle LVDS interface reset Date: Tue, 14 Aug 2018 15:50:02 +0200 Message-Id: <1534254604-24204-9-git-send-email-uli+renesas@fpond.eu> In-Reply-To: <1534254604-24204-1-git-send-email-uli+renesas@fpond.eu> References: <1534254604-24204-1-git-send-email-uli+renesas@fpond.eu> Sender: linux-renesas-soc-owner@vger.kernel.org List-ID: From: Jacopo Mondi The processor manual prescribes to clear reset of LVDS interface in CPG/MSSR module before display on, and to assert the same reset line at display off time, to have the module resuming in a known state. The module is said to be in "standby state" at initialization time, and this requires, according to section 37.3.7 of the manual, to de-assert the reset to have it functional. Based on the original patch from Koji Matsuoka Signed-off-by: Jacopo Mondi Signed-off-by: Ulrich Hecht --- drivers/gpu/drm/rcar-du/rcar_lvds.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c index cd55576..f6a4f9c 100644 --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -55,6 +56,7 @@ struct rcar_lvds { void __iomem *mmio; struct clk *clock; + struct reset_control *rst; bool enabled; struct drm_display_mode display_mode; @@ -385,6 +387,12 @@ static void rcar_lvds_enable(struct drm_bridge *bridge) if (ret < 0) return; + ret = reset_control_deassert(lvds->rst); + if (ret < 0) { + clk_disable_unprepare(lvds->clock); + return; + } + /* * Hardcode the channels and control signals routing for now. * @@ -476,6 +484,7 @@ static void rcar_lvds_disable(struct drm_bridge *bridge) rcar_lvds_write(lvds, LVDCR1, 0); rcar_lvds_write(lvds, LVDPLLCR, 0); + reset_control_assert(lvds->rst); clk_disable_unprepare(lvds->clock); lvds->enabled = false; @@ -692,6 +701,12 @@ static int rcar_lvds_probe(struct platform_device *pdev) return PTR_ERR(lvds->clock); } + lvds->rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL); + if (IS_ERR(lvds->rst)) { + dev_err(&pdev->dev, "failed to get reset\n"); + return PTR_ERR(lvds->rst); + } + drm_bridge_add(&lvds->bridge); return 0; -- 2.7.4