From nobody Wed Dec 17 19:03:21 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 4076DC77B7F for ; Wed, 3 May 2023 16:33:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229689AbjECQdp (ORCPT ); Wed, 3 May 2023 12:33:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229502AbjECQdm (ORCPT ); Wed, 3 May 2023 12:33:42 -0400 Received: from mail.fris.de (mail.fris.de [116.203.77.234]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 673B94EF9 for ; Wed, 3 May 2023 09:33:38 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 6AFF5BFBA7; Wed, 3 May 2023 18:33:35 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fris.de; s=dkim; t=1683131616; h=from:subject:date:message-id:to:cc:mime-version: content-transfer-encoding:in-reply-to:references; bh=XpB9Qsa5ysbMqR5vQpemAUlG5S8C8bacv3P8I3Dbn2Q=; b=CgseNmfWzz5i1BKVwb2ndpUP21VlGSBMvwIHZ0pXLuLpGSUnuwT7dFHPpdiYHqYAE3ll43 b6QriMM6PFrKmemHLibj4YeGxf1wy7jRak9nxGAwR7JovCzdwsSwr5YgsfmI5j09wF5wj6 R3Epht6IA6FwRj2reSNkCPc3lTn2cAL2cb9BlQ+wLNbbNJBeYu2Fb/kZ+33Sqw3fHXlUmP pdAsqqxp96Yqu5LYpk1mNRYarLq9J595VY6RZyTzK9sgtf8UTXwPLo4VqDmb4RW3NbG9JO ICxvQIsmTsocEcvsnd3doTslg6p7SXolxWDoMemNzV3aZH43zbt49ktPNnQsaw== From: Frieder Schrempf To: Andrzej Hajda , Daniel Vetter , David Airlie , dri-devel@lists.freedesktop.org, Inki Dae , Jagan Teki , linux-kernel@vger.kernel.org, Marek Szyprowski , Neil Armstrong , Robert Foss Cc: Frieder Schrempf , Jernej Skrabec , Jonas Karlman , Laurent Pinchart , Marek Vasut Subject: [PATCH v2 1/2] drm: bridge: samsung-dsim: Fix i.MX8M enable flow to meet spec Date: Wed, 3 May 2023 18:33:06 +0200 Message-Id: <20230503163313.2640898-2-frieder@fris.de> In-Reply-To: <20230503163313.2640898-1-frieder@fris.de> References: <20230503163313.2640898-1-frieder@fris.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Last-TLS-Session-Version: TLSv1.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Frieder Schrempf According to the documentation [1] the proper enable flow is: 1. Enable DSI link and keep data lanes in LP-11 (stop state) 2. Disable stop state to bring data lanes into HS mode Currently we do this all at once within enable(), which doesn't allow to meet the requirements of some downstream bridges. To fix this we now enable the DSI in pre_enable() and force it into stop state using the FORCE_STOP_STATE bit in the ESCMODE register until enable() is called where we reset the bit. We currently do this only for i.MX8M as Exynos uses a different init flow where samsung_dsim_init() is called from samsung_dsim_host_transfer(). [1] https://docs.kernel.org/gpu/drm-kms-helpers.html#mipi-dsi-bridge-operat= ion Signed-off-by: Frieder Schrempf Reviewed-by: Neil Armstrong Tested-by: Alexander Stein #TQMa8MxML/MBa= 8Mx --- Changes for v2: * Drop RFC --- drivers/gpu/drm/bridge/samsung-dsim.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge= /samsung-dsim.c index e0a402a85787..9775779721d9 100644 --- a/drivers/gpu/drm/bridge/samsung-dsim.c +++ b/drivers/gpu/drm/bridge/samsung-dsim.c @@ -859,6 +859,10 @@ static int samsung_dsim_init_link(struct samsung_dsim = *dsi) reg =3D samsung_dsim_read(dsi, DSIM_ESCMODE_REG); reg &=3D ~DSIM_STOP_STATE_CNT_MASK; reg |=3D DSIM_STOP_STATE_CNT(driver_data->reg_values[STOP_STATE_CNT]); + + if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) + reg |=3D DSIM_FORCE_STOP_STATE; + samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); =20 reg =3D DSIM_BTA_TIMEOUT(0xff) | DSIM_LPDR_TIMEOUT(0xffff); @@ -1340,6 +1344,9 @@ static void samsung_dsim_atomic_pre_enable(struct drm= _bridge *bridge, ret =3D samsung_dsim_init(dsi); if (ret) return; + + samsung_dsim_set_display_mode(dsi); + samsung_dsim_set_display_enable(dsi, true); } } =20 @@ -1347,9 +1354,16 @@ static void samsung_dsim_atomic_enable(struct drm_br= idge *bridge, struct drm_bridge_state *old_bridge_state) { struct samsung_dsim *dsi =3D bridge_to_dsi(bridge); + u32 reg; =20 - samsung_dsim_set_display_mode(dsi); - samsung_dsim_set_display_enable(dsi, true); + if (samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) { + samsung_dsim_set_display_mode(dsi); + samsung_dsim_set_display_enable(dsi, true); + } else { + reg =3D samsung_dsim_read(dsi, DSIM_ESCMODE_REG); + reg &=3D ~DSIM_FORCE_STOP_STATE; + samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); + } =20 dsi->state |=3D DSIM_STATE_VIDOUT_AVAILABLE; } @@ -1358,10 +1372,17 @@ static void samsung_dsim_atomic_disable(struct drm_= bridge *bridge, struct drm_bridge_state *old_bridge_state) { struct samsung_dsim *dsi =3D bridge_to_dsi(bridge); + u32 reg; =20 if (!(dsi->state & DSIM_STATE_ENABLED)) return; =20 + if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) { + reg =3D samsung_dsim_read(dsi, DSIM_ESCMODE_REG); + reg |=3D DSIM_FORCE_STOP_STATE; + samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); + } + dsi->state &=3D ~DSIM_STATE_VIDOUT_AVAILABLE; } =20 --=20 2.40.0