From patchwork Wed May 4 14:34:32 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Wu X-Patchwork-Id: 9015111 Return-Path: X-Original-To: patchwork-linux-arm@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 44EEF9F39D for ; Wed, 4 May 2016 14:36:39 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 52CAD203AB for ; Wed, 4 May 2016 14:36:38 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F36E9203AE for ; Wed, 4 May 2016 14:36:36 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1axxtc-0002QU-F5; Wed, 04 May 2016 14:35:24 +0000 Received: from lucky1.263xmail.com ([211.157.147.130]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1axxtZ-00019f-Hl; Wed, 04 May 2016 14:35:22 +0000 Received: from david.wu?rock-chips.com (unknown [192.168.167.228]) by lucky1.263xmail.com (Postfix) with SMTP id 28F6C1EE833; Wed, 4 May 2016 22:34:55 +0800 (CST) X-263anti-spam: KSV:0; X-MAIL-GRAY: 1 X-MAIL-DELIVERY: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 X-KSVirus-check: 0 Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.263.net (Postfix) with ESMTP id 8117D3E53; Wed, 4 May 2016 22:34:52 +0800 (CST) X-RL-SENDER: david.wu@rock-chips.com X-FST-TO: heiko@sntech.de X-SENDER-IP: 58.22.7.114 X-LOGIN-NAME: david.wu@rock-chips.com X-UNIQUE-TAG: <2e8583be88d55755fb0c35fc06c15876> X-ATTACHMENT-NUM: 0 X-SENDER: wdc@rock-chips.com X-DNS-TYPE: 0 Received: from localhost.localdomain (unknown [58.22.7.114]) by smtp.263.net (Postfix) whith ESMTP id 22232T7NN0S; Wed, 04 May 2016 22:34:54 +0800 (CST) From: David Wu To: heiko@sntech.de, wsa@the-dreams.de Subject: [PATCH v7 6/9] i2c: rk3x: Move spec timing data to "static const" structs Date: Wed, 4 May 2016 22:34:32 +0800 Message-Id: <1462372472-6396-1-git-send-email-david.wu@rock-chips.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1462371194-5809-1-git-send-email-david.wu@rock-chips.com> References: <1462371194-5809-1-git-send-email-david.wu@rock-chips.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160504_073522_049392_72C58F76 X-CRM114-Status: GOOD ( 10.95 ) X-Spam-Score: -1.9 (-) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, huangtao@rock-chips.com, xjq@rock-chips.com, hl@rock-chips.com, pawel.moll@arm.com, ijc+devicetree@hellion.org.uk, devicetree@vger.kernel.org, linux-rockchip@lists.infradead.org, David Wu , dianders@chromium.org, linux-kernel@vger.kernel.org, cf@rock-chips.com, andy.shevchenko@gmail.com, robh+dt@kernel.org, linux-i2c@vger.kernel.org, galak@codeaurora.org, zyw@rock-chips.com, briannorris@google.com, davidriley@google.com, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-6.3 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 Signed-off-by: David Wu Reviewed-by: Douglas Anderson --- drivers/i2c/busses/i2c-rk3x.c | 100 ++++++++++++++++++++++++++++++------------ 1 file changed, 72 insertions(+), 28 deletions(-) diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c index 9686c81..408f9ab 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -76,6 +76,51 @@ enum { #define DEFAULT_SCL_RATE (100 * 1000) /* Hz */ /** + * struct i2c_spec_values: + * @min_hold_start_ns: min hold time (repeated) START condition + * @min_low_ns: min LOW period of the SCL clock + * @min_high_ns: min HIGH period of the SCL cloc + * @min_setup_start_ns: min set-up time for a repeated START conditio + * @max_data_hold_ns: max data hold time + * @min_data_setup_ns: min data set-up time + * @min_setup_stop_ns: min set-up time for STOP condition + * @min_hold_buffer_ns: min bus free time between a STOP and + * START condition + */ +struct i2c_spec_values { + unsigned long min_hold_start_ns; + unsigned long min_low_ns; + unsigned long min_high_ns; + unsigned long min_setup_start_ns; + unsigned long max_data_hold_ns; + unsigned long min_data_setup_ns; + unsigned long min_setup_stop_ns; + unsigned long min_hold_buffer_ns; +}; + +static const struct i2c_spec_values standard_mode_spec = { + .min_hold_start_ns = 4000, + .min_low_ns = 4700, + .min_high_ns = 4000, + .min_setup_start_ns = 4700, + .max_data_hold_ns = 3450, + .min_data_setup_ns = 250, + .min_setup_stop_ns = 4000, + .min_hold_buffer_ns = 4700, +}; + +static const struct i2c_spec_values fast_mode_spec = { + .min_hold_start_ns = 600, + .min_low_ns = 1300, + .min_high_ns = 600, + .min_setup_start_ns = 600, + .max_data_hold_ns = 900, + .min_data_setup_ns = 100, + .min_setup_stop_ns = 600, + .min_hold_buffer_ns = 1300, +}; + +/** * struct rk3x_i2c_calced_timings: * @div_low: Divider output for low * @div_high: Divider output for high @@ -463,6 +508,21 @@ out: } /** + * Get timing values of I2C specification + * + * @speed: Desired SCL frequency + * + * Returns: Matched i2c spec values. + */ +static const struct i2c_spec_values *rk3x_i2c_get_spec(unsigned int speed) +{ + if (speed <= 100000) + return &standard_mode_spec; + else + return &fast_mode_spec; +} + +/** * Calculate divider values for desired SCL frequency * * @clk_rate: I2C input clock rate @@ -477,10 +537,6 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, struct i2c_timings *t, struct rk3x_i2c_calced_timings *t_calc) { - unsigned long spec_min_low_ns, spec_min_high_ns; - unsigned long spec_setup_start, spec_max_data_hold_ns; - unsigned long data_hold_buffer_ns; - unsigned long min_low_ns, min_high_ns; unsigned long max_low_ns, min_total_ns; @@ -492,6 +548,8 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, unsigned long min_div_for_hold, min_total_div; unsigned long extra_div, extra_low_div, ideal_low_div; + unsigned long data_hold_buffer_ns = 50; + const struct i2c_spec_values *spec; int ret = 0; /* Only support standard-mode and fast-mode */ @@ -514,22 +572,8 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, * This is because the i2c host on Rockchip holds the data line * for half the low time. */ - if (t->bus_freq_hz <= 100000) { - /* Standard-mode */ - spec_min_low_ns = 4700; - spec_setup_start = 4700; - spec_min_high_ns = 4000; - spec_max_data_hold_ns = 3450; - data_hold_buffer_ns = 50; - } else { - /* Fast-mode */ - spec_min_low_ns = 1300; - spec_setup_start = 600; - spec_min_high_ns = 600; - spec_max_data_hold_ns = 900; - data_hold_buffer_ns = 50; - } - min_high_ns = t->scl_rise_ns + spec_min_high_ns; + spec = rk3x_i2c_get_spec(t->bus_freq_hz); + min_high_ns = t->scl_rise_ns + spec->min_high_ns; /* * Timings for repeated start: @@ -539,14 +583,14 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, * We need to account for those rules in picking our "high" time so * we meet tSU;STA and tHD;STA times. */ - min_high_ns = max(min_high_ns, - DIV_ROUND_UP((t->scl_rise_ns + spec_setup_start) * 1000, 875)); - min_high_ns = max(min_high_ns, - DIV_ROUND_UP((t->scl_rise_ns + spec_setup_start + - t->sda_fall_ns + spec_min_high_ns), 2)); - - min_low_ns = t->scl_fall_ns + spec_min_low_ns; - max_low_ns = spec_max_data_hold_ns * 2 - data_hold_buffer_ns; + min_high_ns = max(min_high_ns, DIV_ROUND_UP( + (t->scl_rise_ns + spec->min_setup_start_ns) * 1000, 875)); + min_high_ns = max(min_high_ns, DIV_ROUND_UP( + (t->scl_rise_ns + spec->min_setup_start_ns + t->sda_fall_ns + + spec->min_high_ns), 2)); + + min_low_ns = t->scl_fall_ns + spec->min_low_ns; + max_low_ns = spec->max_data_hold_ns * 2 - data_hold_buffer_ns; min_total_ns = min_low_ns + min_high_ns; /* Adjust to avoid overflow */