From patchwork Sun Oct 30 20:33:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Zaidman X-Patchwork-Id: 620361 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 E2C0CFA3748 for ; Sun, 30 Oct 2022 20:34:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229819AbiJ3Ueo (ORCPT ); Sun, 30 Oct 2022 16:34:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229798AbiJ3Ueg (ORCPT ); Sun, 30 Oct 2022 16:34:36 -0400 Received: from mail-wr1-x42c.google.com (mail-wr1-x42c.google.com [IPv6:2a00:1450:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B20FCB1E8; Sun, 30 Oct 2022 13:34:35 -0700 (PDT) Received: by mail-wr1-x42c.google.com with SMTP id bs21so13454278wrb.4; Sun, 30 Oct 2022 13:34:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=YSSvluQm3NGC5J6X42oGu/YUSo51/OoBhNLx5zGbzEw=; b=VsvBHYDiL+FDN9DKjUQwmovPnjmlpOfI/8bv6P5mWEioGjsozIiiVVcFhxPCGCP9D5 O5cG4jet50RlXXSxlw6c+hF+qnJ+VRmrdk3CNstRNmKddAKEy+vBq6iPeMeRcZQYKVa+ 39qSpX/f1Bo+xTb6CPwl9VahH57WB6Tks03XNWCIkQm4W7QKeI0whC+LvshAk4XpPbGr 1KAaVI8GxnFGbXdhAR4Wd+9assORv6r8tU0A+CcTKwL6ZItei2ONxOoQSRQGImkITV4x RMDmkJcBF3RxbKzY+23Z0zZYlTDyG8iFIf/eSy1rOpTHavtXirPvKaeaYfFmUnZ9JucR fBtQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=YSSvluQm3NGC5J6X42oGu/YUSo51/OoBhNLx5zGbzEw=; b=zh3qc3nhGYs9ySlJKW6h6+9FdZDnDKLKfA7KeOZV2TJHovJGHZ3irfrajRMtnJH9d5 GeZ0QQyzuYQvxGQ9h+dNXRQlwaOKFxQAtFYT94DlWr+gUl4A4jFzxRalZGmIDNXIdbGb 8e1A7m31r+QjzyDWrIIS3KKeEvqqgjyvjwRsSxcEcboVtRLDqTODvXpAQ24vOK4f9Cp6 eZfJCTQArHx9E5p51LCvxunij/ChBr2yueCpMZZgcKWCmPC8VvrnEL6JNLZFrOGkCw97 RB9UGHMEP8c4YuMPN+aBD4F8NNn794TJDCnSzmZe1JqsdBebIu5fyBJrINMZoa9lwzU4 hXyQ== X-Gm-Message-State: ACrzQf286G0nBXF8CgWTHHcMXEpSCGrc5bankHF3D8fC33utSRET7m3S 6/58QxsuCToRRrmQgiawsvM= X-Google-Smtp-Source: AMsMyM6hCI+tWbEhji8iIg5DuxmfJQxC/JVelrtGfB2kVWhzw1ZEzAiDs+DSWJIqn/NmN6zCjXRSXA== X-Received: by 2002:a5d:5f04:0:b0:236:cae9:2991 with SMTP id cl4-20020a5d5f04000000b00236cae92991mr1321897wrb.120.1667162073985; Sun, 30 Oct 2022 13:34:33 -0700 (PDT) Received: from michael-VirtualBox.. (89-139-44-91.bb.netvision.net.il. [89.139.44.91]) by smtp.googlemail.com with ESMTPSA id n25-20020a05600c181900b003b95ed78275sm4939385wmp.20.2022.10.30.13.34.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Oct 2022 13:34:33 -0700 (PDT) From: Michael Zaidman To: jikos@kernel.org Cc: linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, linux-i2c@vger.kernel.org, germain.hebert@ca.abb.com, Enrik.Berkhan@inka.de, Michael Zaidman Subject: [PATCH v3 05/12] HID: ft260: improve i2c large reads performance Date: Sun, 30 Oct 2022 22:33:56 +0200 Message-Id: <20221030203403.4637-6-michael.zaidman@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221030203403.4637-1-michael.zaidman@gmail.com> References: <20221030203403.4637-1-michael.zaidman@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org The patch increases the read buffer size to 180 bytes. It reduces the number of ft260_i2c_read() calls by three, improving the big reads performance. $ sudo i2ctransfer -y -f 13 w2@0x51 0x0 0x0 r180 Before: [ +4.071878] ft260_i2c_write_read: off 0x0 rlen 180 wlen 2 [ +0.000005] ft260_i2c_write: rep 0xd0 addr 0x51 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.001097] ft260_xfer_status: bus_status 0x41, clock 100 [ +0.000175] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000004] ft260_i2c_read: rep 0xc2 addr 0x51 len 180 rlen 60 flag 0x3 [ +0.008579] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000208] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000001] ft260_i2c_read: rep 0xc2 addr 0x51 len 120 rlen 60 flag 0x0 [ +0.008794] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000181] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000002] ft260_i2c_read: rep 0xc2 addr 0x51 len 60 rlen 60 flag 0x4 [ +0.008817] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000223] ft260_xfer_status: bus_status 0x20, clock 100 After: [ +11.611642] ft260_i2c_write_read: off 0x0 rlen 180 wlen 2 [ +0.000005] ft260_i2c_write: rep 0xd0 addr 0x51 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.008001] ft260_xfer_status: bus_status 0x20, clock 100 [ +0.000001] ft260_i2c_read: rep 0xc2 addr 0x51 len 180 rlen 180 flag 0x7 [ +0.008994] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.007987] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.007992] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000206] ft260_xfer_status: bus_status 0x20, clock 100 Suggested-by: Enrik Berkhan Signed-off-by: Michael Zaidman --- drivers/hid/hid-ft260.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c index a354089bb747..91f9087e49dc 100644 --- a/drivers/hid/hid-ft260.c +++ b/drivers/hid/hid-ft260.c @@ -30,12 +30,19 @@ MODULE_PARM_DESC(debug, "Toggle FT260 debugging messages"); #define FT260_REPORT_MAX_LENGTH (64) #define FT260_I2C_DATA_REPORT_ID(len) (FT260_I2C_REPORT_MIN + (len - 1) / 4) + /* - * The input report format assigns 62 bytes for the data payload, but ft260 - * returns 60 and 2 in two separate transactions. To minimize transfer time - * in reading chunks mode, set the maximum read payload length to 60 bytes. - */ -#define FT260_RD_DATA_MAX (60) + * The ft260 input report format defines 62 bytes for the data payload, but + * when requested 62 bytes, the controller returns 60 and 2 in separate input + * reports. To achieve better performance with the multi-report read data + * transfers, we set the maximum read payload length to a multiple of 60. + * With a 100 kHz I2C clock, one 240 bytes read takes about 1/27 second, + * which is excessive; On the other hand, some higher layer drivers like at24 + * or optoe limit the i2c reads to 128 bytes. To not block other drivers out + * of I2C for potentially troublesome amounts of time, we select the maximum + * read payload length to be 180 bytes. +*/ +#define FT260_RD_DATA_MAX (180) #define FT260_WR_DATA_MAX (60) /*