From patchwork Fri Feb 24 12:54:56 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Keeping X-Patchwork-Id: 9590039 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 892C9601AE for ; Fri, 24 Feb 2017 12:55:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 523A52875B for ; Fri, 24 Feb 2017 12:55:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4710928783; Fri, 24 Feb 2017 12:55:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id F00E62875B for ; Fri, 24 Feb 2017 12:55:30 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3998F6EC36; Fri, 24 Feb 2017 12:55:23 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from metanate.com (dougal.metanate.com [90.155.101.14]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5D8186EC33 for ; Fri, 24 Feb 2017 12:55:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=simple/simple; d=metanate.com; s=stronger; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=RQidnUzwQjjxYiu0CDbkeBYWvH+lUsyGumaKXmVuq7Q=; b=d7vSpyTCKBhsMWBLhAp4VGDVbpu9i/eId9PUImS+1KZpqlVt/OY6NQqJyC/ID+U/+WJQ9OFEjqaOAF8ybD/y8tdfAh7RacR5eqbI8VO6Rh27LBrGysGetPcm9Oe9BB8LEHmvsvIfSImtiOH+ED0tY1RIYNZCkPkLdIrhDwWwPou21SDlNlHM9goiCyxU63ENESNFlqkOABt9IU99tgjxDF8WI4hxA2QymSYyDVCdh2Pr+6wiwCmPLANNb3ncnUNTVvboHH+6ETQKpU0wWoJydLnUHCtSs4mwMqW6LiRAuTVOqB6WDrn1moRhW+YMpIjmGr6/JeRE7tX4HUcsY8353A==; Received: from brian ([192.168.88.1] helo=leela.metanate.com) by shrek.metanate.com with esmtpsa (TLSv1.2:DHE-RSA-AES128-GCM-SHA256:128) (Exim 4.83_RC2) (envelope-from ) id 1chFP1-0006ml-22; Fri, 24 Feb 2017 12:55:15 +0000 From: John Keeping To: Mark Yao Subject: [PATCH v4 13/23] drm/rockchip: dw-mipi-dsi: fix escape clock rate Date: Fri, 24 Feb 2017 12:54:56 +0000 Message-Id: <20170224125506.21533-14-john@metanate.com> X-Mailer: git-send-email 2.12.0.rc0.230.gf625d4cdb9.dirty In-Reply-To: <20170224125506.21533-1-john@metanate.com> References: <20170224125506.21533-1-john@metanate.com> Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-rockchip@lists.infradead.org, Chris Zhong , linux-arm-kernel@lists.infradead.org X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP This clock rate is derived from the PHY PLL, so it should be calculated dynamically. This calculation is the same as that used by the vendor kernel and ensures that the escape clock runs at <20MHz as required by the MIPI specification. Signed-off-by: John Keeping Reviewed-by: Chris Zhong Reviewed-by: Sean Paul --- v4: - Add a comment explaining the calculation and reword the commit message so that the calculation doesn't seem so magical - Add Sean's Reviewed-by v3: - Improve the commit message a bit - Add Chris' Reviewed-by Unchanged in v2 --- drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c index 4201a2143295..0f9be41f0361 100644 --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c @@ -712,11 +712,21 @@ static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi) static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi) { + /* + * The maximum permitted escape clock is 20MHz and it is derived from + * lanebyteclk, which is running at "lane_mbps / 8". Thus we want: + * + * (lane_mbps >> 3) / esc_clk_division < 20 + * which is: + * (lane_mbps >> 3) / 20 > esc_clk_division + */ + u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1; + dsi_write(dsi, DSI_PWR_UP, RESET); dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK | PHY_RSTZ | PHY_SHUTDOWNZ); dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) | - TX_ESC_CLK_DIVIDSION(7)); + TX_ESC_CLK_DIVIDSION(esc_clk_division)); } static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,