From patchwork Mon Dec 18 21:58:01 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 850440 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3z0vzs5gMHz9sBW for ; Tue, 19 Dec 2017 08:58:17 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965390AbdLRV6Q (ORCPT ); Mon, 18 Dec 2017 16:58:16 -0500 Received: from sauhun.de ([88.99.104.3]:40909 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965215AbdLRV6L (ORCPT ); Mon, 18 Dec 2017 16:58:11 -0500 Received: from localhost (p54B33BFB.dip0.t-ipconnect.de [84.179.59.251]) by pokefinder.org (Postfix) with ESMTPSA id 90BC92C632C; Mon, 18 Dec 2017 22:58:09 +0100 (CET) From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-renesas-soc@vger.kernel.org, Yoshihiro Shimoda , Wolfram Sang Subject: [RFC PATCH 6/7] i2c: sh_mobile: add new frequency calculation for later SoC Date: Mon, 18 Dec 2017 22:58:01 +0100 Message-Id: <20171218215802.28591-7-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171218215802.28591-1-wsa+renesas@sang-engineering.com> References: <20171218215802.28591-1-wsa+renesas@sang-engineering.com> Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org The formula to generate the desired bus speeds has changed a little over time. Implement the new formula and allow drivers to opt-in by changing to this new config set. Ensure in probe that we don't divide by zero. The returned values on a R-Car H2 (r8a7790/Lager board) match the suggested values in the datasheet. Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-sh_mobile.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c index b111191a449a69..a0fddfe3c4497d 100644 --- a/drivers/i2c/busses/i2c-sh_mobile.c +++ b/drivers/i2c/busses/i2c-sh_mobile.c @@ -299,6 +299,18 @@ static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd) return sh_mobile_i2c_check_timing(pd); } +static int sh_mobile_i2c_v2_init(struct sh_mobile_i2c_data *pd) +{ + unsigned long clks_per_cycle; + + /* L = 5, H = 4, L + H = 9 */ + clks_per_cycle = clk_get_rate(pd->clk) / pd->bus_speed; + pd->iccl = DIV_ROUND_UP(clks_per_cycle * 5 / 9 - 1, pd->clks_per_count); + pd->icch = DIV_ROUND_UP(clks_per_cycle * 4 / 9 - 5, pd->clks_per_count); + + return sh_mobile_i2c_check_timing(pd); +} + static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, enum sh_mobile_i2c_op op, unsigned char data) { @@ -785,6 +797,11 @@ static const struct sh_mobile_dt_config fast_clock_dt_config = { .setup = sh_mobile_i2c_init, }; +static const struct sh_mobile_dt_config v2_freq_calc_dt_config = { + .clks_per_count = 2, + .setup = sh_mobile_i2c_v2_init, +}; + static const struct sh_mobile_dt_config r8a7740_dt_config = { .clks_per_count = 1, .setup = sh_mobile_i2c_r8a7740_workaround, @@ -875,7 +892,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev) return PTR_ERR(pd->reg); ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed); - pd->bus_speed = ret ? STANDARD_MODE : bus_speed; + pd->bus_speed = (ret || !bus_speed) ? STANDARD_MODE : bus_speed; pd->clks_per_count = 1; /* Newer variants come with two new bits in ICIC */