From patchwork Thu Nov 26 22:59:13 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 7709311 X-Patchwork-Delegate: horms@verge.net.au Return-Path: X-Original-To: patchwork-linux-sh@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 A95059F54F for ; Thu, 26 Nov 2015 22:59:48 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id BF14C205BB for ; Thu, 26 Nov 2015 22:59:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE0F4205C6 for ; Thu, 26 Nov 2015 22:59:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753505AbbKZW7m (ORCPT ); Thu, 26 Nov 2015 17:59:42 -0500 Received: from sauhun.de ([89.238.76.85]:36543 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753408AbbKZW72 (ORCPT ); Thu, 26 Nov 2015 17:59:28 -0500 Received: from p4fe258bf.dip0.t-ipconnect.de ([79.226.88.191]:40127 helo=localhost) by pokefinder.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1a25Vc-0001IL-OB; Thu, 26 Nov 2015 23:59:25 +0100 From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-sh@vger.kernel.org, Magnus Damm , Simon Horman , Laurent Pinchart , Geert Uytterhoeven , Wolfram Sang , Yoshihiro Shimoda Subject: [RFC 5/9] i2c: rcar: honor additional i2c timings from DT Date: Thu, 26 Nov 2015 23:59:13 +0100 Message-Id: <1448578757-12613-6-git-send-email-wsa@the-dreams.de> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1448578757-12613-1-git-send-email-wsa@the-dreams.de> References: <1448578757-12613-1-git-send-email-wsa@the-dreams.de> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham 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 From: Wolfram Sang Signed-off-by: Wolfram Sang --- Documentation/devicetree/bindings/i2c/i2c-rcar.txt | 4 ++++ drivers/i2c/busses/i2c-rcar.c | 21 ++++++++++++--------- 2 files changed, 16 insertions(+), 9 deletions(-) diff --git a/Documentation/devicetree/bindings/i2c/i2c-rcar.txt b/Documentation/devicetree/bindings/i2c/i2c-rcar.txt index ea406eb20fa5ad..95e97223a71c83 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-rcar.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-rcar.txt @@ -20,6 +20,10 @@ Optional properties: propoerty indicates the default frequency 100 kHz. - clocks: clock specifier. +- i2c-scl-falling-time-ns: see i2c.txt +- i2c-scl-internal-delay-ns: see i2c.txt +- i2c-scl-rising-time-ns: see i2c.txt + Examples : i2c0: i2c@e6508000 { diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 453ce10132025d..9465a23bcc91a5 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -164,12 +164,15 @@ static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv) static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv, struct i2c_timings *t) { - u32 scgd, cdf, round, ick, scl, cdf_width; + u32 scgd, cdf, round, ick, sum, scl, cdf_width; unsigned long rate; struct device *dev = rcar_i2c_priv_to_dev(priv); /* Fall back to previously used values if not supplied */ t->bus_freq = t->bus_freq ?: 100000; + t->scl_fall_ns = t->scl_fall_ns ?: 35; + t->scl_rise_ns = t->scl_rise_ns ?: 200; + t->scl_int_delay_ns = t->scl_int_delay_ns ?: 50; switch (priv->devtype) { case I2C_RCAR_GEN1: @@ -193,9 +196,9 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv, struct i2c_timin * SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick]) * * ick : I2C internal clock < 20 MHz - * ticf : I2C SCL falling time = 35 ns here - * tr : I2C SCL rising time = 200 ns here - * intd : LSI internal delay = 50 ns here + * ticf : I2C SCL falling time + * tr : I2C SCL rising time + * intd : LSI internal delay * clkp : peripheral_clk * F[] : integer up-valuation */ @@ -211,12 +214,12 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv, struct i2c_timin * it is impossible to calculate large scale * number on u32. separate it * - * F[(ticf + tr + intd) * ick] - * = F[(35 + 200 + 50)ns * ick] - * = F[285 * ick / 1000000000] - * = F[(ick / 1000000) * 285 / 1000] + * F[(ticf + tr + intd) * ick] with sum = (ticf + tr + intd) + * = F[sum * ick / 1000000000] + * = F[(ick / 1000000) * sum / 1000] */ - round = (ick + 500000) / 1000000 * 285; + sum = t->scl_fall_ns + t->scl_rise_ns + t->scl_int_delay_ns; + round = (ick + 500000) / 1000000 * sum; round = (round + 500) / 1000; /*