From patchwork Wed Dec 18 22:35:27 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 11302379 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 6066B14B7 for ; Wed, 18 Dec 2019 22:36:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3F64524676 for ; Wed, 18 Dec 2019 22:36:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="FkUP63X0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726828AbfLRWgF (ORCPT ); Wed, 18 Dec 2019 17:36:05 -0500 Received: from mail-pj1-f67.google.com ([209.85.216.67]:53645 "EHLO mail-pj1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726817AbfLRWgF (ORCPT ); Wed, 18 Dec 2019 17:36:05 -0500 Received: by mail-pj1-f67.google.com with SMTP id n96so1537336pjc.3 for ; Wed, 18 Dec 2019 14:36:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=HWLrCBmbQYNUzFqSBsWhDuxG2CTjfW4UctSr9zQlrcM=; b=FkUP63X0pjdoYGeSCmX+sTsW3UjT9Iz4YMXkcnYAADSytPIkCdf3qU+AXOzHvbSTIT 4YHXU58YEBKhpv87PiKXMPiSl3b5z9J71lpbY4YRBDpBtgH+BoYKzHUa6v/unmJRZk3J zR76WEhs7n5zByU++Zj9kBjfUSflVwowSoOnY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=HWLrCBmbQYNUzFqSBsWhDuxG2CTjfW4UctSr9zQlrcM=; b=ZPF5tt47Xl+quKDPdmeiZxtCPbr6LfnlE06rXmyyjPcKEz4jgY11Ik1DBECyrsevnW bhmnxPDmhwJ/QOPfZJnDRLUkjwXuqorkXo5V99waK7Opd3fPz/HLC5RaT4SYMchSqE+g G28lcJv6E258ZxMMKyT2I5LIphTYeZJBSti0UB217Q1CPq2U1S0rPywYo79ptHCZZ4nK IBuk0vDIwn5PMBvtQKcBi3zHKQ6ZIaBUW0ks41zSSuiGmDb0SN1kqRoDhha5HVUq10oV sqKUddBni0JOUG8t+Wk9WhmkplIXiG6tgxIBUz3iUOEh1qR2L3RvWKqmH0R4WZF/0ODc Jvlw== X-Gm-Message-State: APjAAAVQY9/9F/g860DYRml/HnqcSBMQ69VgbsYxx+W5unnihVjDSOLr 860anPkwSKgvIOhotqDjVInImA== X-Google-Smtp-Source: APXvYqyqdXK6Wz2oJpw/C/l5gEu2n1oknYoDT7ccWZpYVnogGsdlgyyemkDssR3QaspTP99E71UUgw== X-Received: by 2002:a17:90a:c24b:: with SMTP id d11mr5970581pjx.128.1576708564377; Wed, 18 Dec 2019 14:36:04 -0800 (PST) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id i9sm4709919pfk.24.2019.12.18.14.36.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Dec 2019 14:36:04 -0800 (PST) From: Douglas Anderson To: Andrzej Hajda , Neil Armstrong Cc: robdclark@chromium.org, linux-arm-msm@vger.kernel.org, bjorn.andersson@linaro.org, seanpaul@chromium.org, Jeffrey Hugo , Daniel Vetter , Douglas Anderson , Rob Clark , Jonas Karlman , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, David Airlie , Jernej Skrabec , Laurent Pinchart Subject: [PATCH v3 6/9] drm/bridge: ti-sn65dsi86: Use 18-bit DP if we can Date: Wed, 18 Dec 2019 14:35:27 -0800 Message-Id: <20191218143416.v3.6.Iaf8d698f4e5253d658ae283d2fd07268076a7c27@changeid> X-Mailer: git-send-email 2.24.1.735.g03f4e72817-goog In-Reply-To: <20191218223530.253106-1-dianders@chromium.org> References: <20191218223530.253106-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org The current bridge driver always forced us to use 24 bits per pixel over the DP link. This is a waste if you are hooked up to a panel that only supports 6 bits per color or fewer, since in that case you ran run at 18 bits per pixel and thus end up at a lower DP clock rate. Let's support this. While at it, let's clean up the math in the function to avoid rounding errors (and round in the correct direction when we have to round). Numbers are sufficiently small (because mode->clock is in kHz) that we don't need to worry about integer overflow. Signed-off-by: Douglas Anderson Tested-by: Rob Clark Reviewed-by: Rob Clark Reviewed-by: Bjorn Andersson --- Changes in v3: None Changes in v2: None drivers/gpu/drm/bridge/ti-sn65dsi86.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 0fc9e97b2d98..d5990a0947b9 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -51,6 +51,7 @@ #define SN_ENH_FRAME_REG 0x5A #define VSTREAM_ENABLE BIT(3) #define SN_DATA_FORMAT_REG 0x5B +#define BPP_18_RGB BIT(0) #define SN_HPD_DISABLE_REG 0x5C #define HPD_DISABLE BIT(0) #define SN_AUX_WDATA_REG(x) (0x64 + (x)) @@ -436,6 +437,14 @@ static void ti_sn_bridge_set_dsi_rate(struct ti_sn_bridge *pdata) regmap_write(pdata->regmap, SN_DSIA_CLK_FREQ_REG, val); } +static unsigned int ti_sn_bridge_get_bpp(struct ti_sn_bridge *pdata) +{ + if (pdata->connector.display_info.bpc <= 6) + return 18; + else + return 24; +} + /** * LUT index corresponds to register value and * LUT values corresponds to dp data rate supported @@ -447,21 +456,17 @@ static const unsigned int ti_sn_bridge_dp_rate_lut[] = { static void ti_sn_bridge_set_dp_rate(struct ti_sn_bridge *pdata) { - unsigned int bit_rate_mhz, dp_rate_mhz; + unsigned int bit_rate_khz, dp_rate_mhz; unsigned int i; struct drm_display_mode *mode = &pdata->bridge.encoder->crtc->state->adjusted_mode; - /* - * Calculate minimum bit rate based on our pixel clock. At - * the moment this driver never sets the DP_18BPP_EN bit in - * register 0x5b so we hardcode 24bpp. - */ - bit_rate_mhz = (mode->clock / 1000) * 24; + /* Calculate minimum bit rate based on our pixel clock. */ + bit_rate_khz = mode->clock * ti_sn_bridge_get_bpp(pdata); /* Calculate minimum DP data rate, taking 80% as per DP spec */ - dp_rate_mhz = ((bit_rate_mhz / pdata->dp_lanes) * DP_CLK_FUDGE_NUM) / - DP_CLK_FUDGE_DEN; + dp_rate_mhz = DIV_ROUND_UP(bit_rate_khz * DP_CLK_FUDGE_NUM, + 1000 * pdata->dp_lanes * DP_CLK_FUDGE_DEN); for (i = 1; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; i++) if (ti_sn_bridge_dp_rate_lut[i] > dp_rate_mhz) @@ -550,6 +555,10 @@ static void ti_sn_bridge_enable(struct drm_bridge *bridge) regmap_update_bits(pdata->regmap, SN_DSI_LANES_REG, CHA_DSI_LANES_MASK, val); + /* Set the DP output format (18 bpp or 24 bpp) */ + val = (ti_sn_bridge_get_bpp(pdata) == 18) ? BPP_18_RGB : 0; + regmap_update_bits(pdata->regmap, SN_DATA_FORMAT_REG, BPP_18_RGB, val); + /* DP lane config */ val = DP_NUM_LANES(min(pdata->dp_lanes, 3)); regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK,