From patchwork Wed Feb 9 09:54:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kewei Xu X-Patchwork-Id: 541595 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F365C4321E for ; Wed, 9 Feb 2022 09:56:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236038AbiBIJ4Q (ORCPT ); Wed, 9 Feb 2022 04:56:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235348AbiBIJ4O (ORCPT ); Wed, 9 Feb 2022 04:56:14 -0500 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ED508DF28ACF; Wed, 9 Feb 2022 01:56:08 -0800 (PST) X-UUID: f47de4b025de4216ae53e6b7a645d804-20220209 X-UUID: f47de4b025de4216ae53e6b7a645d804-20220209 Received: from mtkmbs10n2.mediatek.inc [(172.21.101.183)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1907449128; Wed, 09 Feb 2022 17:54:14 +0800 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.15; Wed, 9 Feb 2022 17:54:13 +0800 Received: from localhost.localdomain (10.17.3.14) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Wed, 9 Feb 2022 17:54:12 +0800 From: Kewei Xu To: CC: , , , , , , , , , , , , , , , , Subject: [PATCH v9 1/1] i2c: mediatek: modify bus speed calculation formula Date: Wed, 9 Feb 2022 17:54:07 +0800 Message-ID: <1644400447-6215-2-git-send-email-kewei.xu@mediatek.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1644400447-6215-1-git-send-email-kewei.xu@mediatek.com> References: <1644400447-6215-1-git-send-email-kewei.xu@mediatek.com> MIME-Version: 1.0 X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org When clock-div is 0 or greater than 1, the bus speed calculated by the old speed calculation formula will be larger than the target speed. So we update the formula. Signed-off-by: Kewei Xu Change-Id: Ic0d9b8ab036bcf215d3a5066f2b91c7b8b128ba6 --- drivers/i2c/busses/i2c-mt65xx.c | 51 +++++++++++++++++++++++++++++++++-------- 1 file changed, 41 insertions(+), 10 deletions(-) diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c index aa4d218..682293e 100644 --- a/drivers/i2c/busses/i2c-mt65xx.c +++ b/drivers/i2c/busses/i2c-mt65xx.c @@ -67,11 +67,12 @@ #define MAX_SAMPLE_CNT_DIV 8 #define MAX_STEP_CNT_DIV 64 -#define MAX_CLOCK_DIV 256 +#define MAX_CLOCK_DIV_8BITS 256 +#define MAX_CLOCK_DIV_5BITS 32 #define MAX_HS_STEP_CNT_DIV 8 -#define I2C_STANDARD_MODE_BUFFER (1000 / 2) -#define I2C_FAST_MODE_BUFFER (300 / 2) -#define I2C_FAST_MODE_PLUS_BUFFER (20 / 2) +#define I2C_STANDARD_MODE_BUFFER (1000 / 3) +#define I2C_FAST_MODE_BUFFER (300 / 3) +#define I2C_FAST_MODE_PLUS_BUFFER (20 / 3) #define I2C_CONTROL_RS (0x1 << 1) #define I2C_CONTROL_DMA_EN (0x1 << 2) @@ -604,6 +605,31 @@ static int mtk_i2c_max_step_cnt(unsigned int target_speed) return MAX_STEP_CNT_DIV; } +static int mtk_i2c_get_clk_div_restri(struct mtk_i2c *i2c, + unsigned int sample_cnt) +{ + int clk_div_restri = 0; + + if (i2c->dev_comp->ltiming_adjust == 0) + return 0; + + if (sample_cnt == 1) { + if (i2c->ac_timing.inter_clk_div == 0) + clk_div_restri = 0; + else + clk_div_restri = 1; + } else { + if (i2c->ac_timing.inter_clk_div == 0) + clk_div_restri = -1; + else if (i2c->ac_timing.inter_clk_div == 1) + clk_div_restri = 0; + else + clk_div_restri = 1; + } + + return clk_div_restri; +} + /* * Check and Calculate i2c ac-timing * @@ -732,6 +758,7 @@ static int mtk_i2c_calculate_speed(struct mtk_i2c *i2c, unsigned int clk_src, unsigned int best_mul; unsigned int cnt_mul; int ret = -EINVAL; + int clk_div_restri = 0; if (target_speed > I2C_MAX_HIGH_SPEED_MODE_FREQ) target_speed = I2C_MAX_HIGH_SPEED_MODE_FREQ; @@ -749,7 +776,8 @@ static int mtk_i2c_calculate_speed(struct mtk_i2c *i2c, unsigned int clk_src, * optimizing for sample_cnt * step_cnt being minimal */ for (sample_cnt = 1; sample_cnt <= MAX_SAMPLE_CNT_DIV; sample_cnt++) { - step_cnt = DIV_ROUND_UP(opt_div, sample_cnt); + clk_div_restri = mtk_i2c_get_clk_div_restri(i2c, sample_cnt); + step_cnt = DIV_ROUND_UP(opt_div + clk_div_restri, sample_cnt); cnt_mul = step_cnt * sample_cnt; if (step_cnt > max_step_cnt) continue; @@ -763,7 +791,7 @@ static int mtk_i2c_calculate_speed(struct mtk_i2c *i2c, unsigned int clk_src, best_mul = cnt_mul; base_sample_cnt = sample_cnt; base_step_cnt = step_cnt; - if (best_mul == opt_div) + if (best_mul == (opt_div + clk_div_restri)) break; } } @@ -774,7 +802,8 @@ static int mtk_i2c_calculate_speed(struct mtk_i2c *i2c, unsigned int clk_src, sample_cnt = base_sample_cnt; step_cnt = base_step_cnt; - if ((clk_src / (2 * sample_cnt * step_cnt)) > target_speed) { + if ((clk_src / (2 * (sample_cnt * step_cnt - clk_div_restri))) > + target_speed) { /* In this case, hardware can't support such * low i2c_bus_freq */ @@ -803,13 +832,16 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk) target_speed = i2c->speed_hz; parent_clk /= i2c->clk_src_div; - if (i2c->dev_comp->timing_adjust) - max_clk_div = MAX_CLOCK_DIV; + if (i2c->dev_comp->timing_adjust && i2c->dev_comp->ltiming_adjust) + max_clk_div = MAX_CLOCK_DIV_5BITS; + else if (i2c->dev_comp->timing_adjust) + max_clk_div = MAX_CLOCK_DIV_8BITS; else max_clk_div = 1; for (clk_div = 1; clk_div <= max_clk_div; clk_div++) { clk_src = parent_clk / clk_div; + i2c->ac_timing.inter_clk_div = clk_div - 1; if (target_speed > I2C_MAX_FAST_MODE_PLUS_FREQ) { /* Set master code speed register */ @@ -856,7 +888,6 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk) break; } - i2c->ac_timing.inter_clk_div = clk_div - 1; return 0; }