From patchwork Wed May 18 15:01:24 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 9120211 Return-Path: X-Original-To: patchwork-dri-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id CA3E39F37F for ; Wed, 18 May 2016 15:02:17 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 054A12035E for ; Wed, 18 May 2016 15:02:17 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 6DC0E20357 for ; Wed, 18 May 2016 15:02:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8D07A6E31D; Wed, 18 May 2016 15:02:10 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from bear.ext.ti.com (bear.ext.ti.com [198.47.19.11]) by gabe.freedesktop.org (Postfix) with ESMTPS id D55646E31D for ; Wed, 18 May 2016 15:02:06 +0000 (UTC) Received: from dflxv15.itg.ti.com ([128.247.5.124]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id u4IF230J022463; Wed, 18 May 2016 10:02:03 -0500 Received: from DFLE73.ent.ti.com (dfle73.ent.ti.com [128.247.5.110]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id u4IF23Rv012320; Wed, 18 May 2016 10:02:03 -0500 Received: from dlep32.itg.ti.com (157.170.170.100) by DFLE73.ent.ti.com (128.247.5.110) with Microsoft SMTP Server id 14.3.294.0; Wed, 18 May 2016 10:02:03 -0500 Received: from deskari.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep32.itg.ti.com (8.14.3/8.13.8) with ESMTP id u4IF1W8Y018729; Wed, 18 May 2016 10:02:02 -0500 From: Tomi Valkeinen To: , Laurent Pinchart Subject: [PATCH 22/24] drm/omap: add comments for PLL calculations Date: Wed, 18 May 2016 18:01:24 +0300 Message-ID: <1463583686-24964-23-git-send-email-tomi.valkeinen@ti.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1463583686-24964-1-git-send-email-tomi.valkeinen@ti.com> References: <1463583686-24964-1-git-send-email-tomi.valkeinen@ti.com> MIME-Version: 1.0 Cc: Tomi Valkeinen 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add comments showing how the PLL clock rates are calculated. Signed-off-by: Tomi Valkeinen --- drivers/gpu/drm/omapdrm/dss/pll.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/omapdrm/dss/pll.c b/drivers/gpu/drm/omapdrm/dss/pll.c index 6daf7bc3a67a..4768a85e6c73 100644 --- a/drivers/gpu/drm/omapdrm/dss/pll.c +++ b/drivers/gpu/drm/omapdrm/dss/pll.c @@ -207,6 +207,10 @@ bool dss_pll_hsdiv_calc_a(const struct dss_pll *pll, unsigned long clkdco, return false; } +/* + * clkdco = clkin / n * m * 2 + * clkoutX = clkdco / mX + */ bool dss_pll_calc_a(const struct dss_pll *pll, unsigned long clkin, unsigned long pll_min, unsigned long pll_max, dss_pll_calc_func func, void *data) @@ -252,6 +256,9 @@ bool dss_pll_calc_a(const struct dss_pll *pll, unsigned long clkin, * This calculates a PLL config that will provide the target_clkout rate * for clkout. Additionally clkdco rate will be the same as clkout rate * when clkout rate is >= min_clkdco. + * + * clkdco = clkin / n * m + clkin / n * mf / 262144 + * clkout = clkdco / m2 */ bool dss_pll_calc_b(const struct dss_pll *pll, unsigned long clkin, unsigned long target_clkout, struct dss_pll_clock_info *cinfo)